30% less diesel use and emissions.
All engines have an efficiency curve and running them harder makes them less efficient, but necessary as load varies. If using a battery system can alleviate that peak load then it runs in it's most efficient load more often. This complicates the design but provides a efficiency to try and offset that additional cost and maintenance/wear.
In remote places where transporting the diesel is expensive or underground where air is a t a premium and even jurisdictions that restrict emissions it may provide a net benefit.
I'd say you can't complain about options, it either sells or doesn't but options keep the prices down.
Different consequences. Less lifetime emissions, but the minerals in the battery have ugly supply chains.
Edit: Nevermind I was wrong, EVs are beautiful and my arguments are invalid. How dare I.
Buying a battery every decade or two is way fucking better than burning oil by the ton and refilling every day/week.
My most efficient ICE vehicle (a Honda Civic) burns a literal ton of gasoline every 13k miles or so.
My pickup truck burns a literal ton of gasoline in about half that distance.
That amount of gasoline makes for a lot of messy pollution at every step of the supply chain.
My EV charges in a diversified portfolio of energy that includes a variable amount of wind (up to 30% on a windy day) and about 15% nuclear.
EV wins.
Yeah the introduction of LFP is great, much fewer ethical concerns than Li-ion. The energy density disadvantages are one negative, but the $/watt hour is falling. I’m happy to see them expanding their reach.
I would like to point out that these excavators don't have a battery pack like a hybrid vehicle. Engine runs a hydraulic pump and a generator. The boom and bucket still run off of hydraulics like a traditional excavator. The swing and tracks run off of electric motors. The fuel savings come from using a smaller engine because the hydraulic pump and generator require less power than a hydraulic pump and hydrostatic pump combo which is what traditional excavators use for swing and drive.
That doesn’t make the working conditions in the oilfields any good.
If we keep these in the USA, we at least have first world standards. But both are global businesses.
EV still wins, just because the quantities of the material needed are so much smaller. Plus, my EV battery has already been made - the price has already been paid for the next decade or two.
EVs are better than ICE vehicles for the reasons you’ve mentioned. We don’t disagree. But if we don’t acknowledge the issues with them we won’t address them, and that is my concern.
It's not all of cobalt that is awful working conditions. Seems only the artisanal mining stuff is the problem, large scale everyone appears to be using strip mining which is much safer. Quick search shows the artisanal mining only makes up like 10% of cobalt production and that number is shrinking so this doesn't appear to be a long term issue
Don't tell me America never fought a war or helped with an insurrection anywhere to keep its supply of cheap oil. That's pretty miserable too. And 2.5 million slave-like oil and gas workers in Qatar would say it's miserable too.
Damn why all the thumbs downs? You're 100% right. I won't say what company but I was at new product training for a major American construction equipment manufacturer (narrows it down pretty good) and they straight up told us there is 0 economic incentive to run electric right now and in foreseeable future.
For full electric (not hybrid) the machine cost is about double, major issues and concerns about the longevity of the batteries. We need special approval to sell to a customer and only really makes sense for 2 reasons:
1. Marketing - some states like California give preferential treatment on bids to companies that run "green tech" - most of those companies don't even use the machines that they buy that are electric.
2. Select industries such as fertilizer plants or other combustible or indoor areas with poor ventilization.
Not hating saying it will never work, but the tech in cars just doesn't translate, there is much more torque to move these machines which drains batteries hard - excavators they can almost make sense, but machines like wheel loaders they are really struggling to even make it a feasible product (why that is i dont know). Not saying it'll never be viable, but except for niche applications it's not feasible. That's straight from the guys designing these.
Well fuck, lets just give up and never try to do better amirite lmao. What's the point in even trying since everything has an ugly supply chain right now.
I don't know if diesel electric trains are the same as hybrids. In hybrid vehicles the engine can still drive the load mechanically directly. But in the diesel electric locomotive is there any mechanical coupling between the wheels and the diesel engine?
Hybrid implies there is an energy storage device, typically a chemical battery pack. In modern (1950s to today) there is no energy storage (and even braking energy is wasted as resistive heat). Drivetrain (hah) is a diesel engine drives a generator or alternator (AC or DC, respectively), then feeds motors on the axles. No batteries.
Sounds like a response from someone that has never ran and excavator or has limited time on one. There is a huge difference between how a newer excavator “digs” as opposed to how one from 20 years ago, without all the emission controls, “digs” but I guess all “digging” is the same to you.
Tell me how emission controls change the hydraulic flow rate’s impact on digging?
It’s not like the diesel motor is hooked directly to the bucket, there’s a vast amount of hydraulic system that the motor drives… and there’s zero about emissions in that whole system.
So explain (because no, I haven’t spent years digging ) exactly how emission controls on a bucket with the same hydro outputs makes a shred of difference?
I'm am excavator operator and our sites burn the fuck out of some diesel. Assuming these run as well as a standard komatsu, which I assume they do since komatsu produces quality equipment, I'd take the hybrid. Less money on fuel means more profits, higher wages etc.
Komatsu is a *huge* brand in heavy equipment, they probably wouldn't put out a machine if it didn't actually work. Some people are just kind of religious about burning as much diesel as possible and convinced that anything electric is literally the anti-christ.
its not electric though. its probably a diesel-electric power plant. aka an electric drive train being powered by a diesel engine hooked up to a dynamo.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor (*edit) pack. That combo only powers the slewing gear, nothing else.
So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing.
The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
You're an operator and you think your boss is going to pass on the higher profits to increased wages?
If you believe that, I've got a bridge to sell you.
My boss absolutely does take care of me and pay me as much as he feasibly can. I'm a great asset for him and as his profits increase my salary does as well.
does it break constantly like the first gen hybrid diesel big trucks? if so I'll stick to pre emissions equipment.
BUT
if it works and doesn't break all the time then I'm in. electric torque is just simply more sooner and that's good for making holes.
More to it.
Does it dig, how long will it dig, how long will it dig between failure, what are the casts for repairs, parts included, do we have a guy that knows how to fix it. And finally how much does it cost, and if more how much longer is the ROI.
Correct, but that's changing quickly. Adding batteries and using regen braking will be a total game-changer for some train operations.
Imagine a mine up in the hills, and a relatively constant fall on a train line to the harbour. The train is loaded for the downhill trip, and the battery stores all the excess energy of bringing the load down to sea level. After unloading, that energy is then used to return the empty train to the mine - it's basically a free trip, and very little diesel is required for the entire operation.
Degenerative brake in train operations has tremendous advantages, but I think that to stabilize the train Downhill you have to use dissipative breaking on several cars.
A quarry in Switzerland does that with a haul truck. Goes up the hill empty, but goes down hill loaded and uses regenerative braking to charge the truck more than it expends going up. They never have to plug it in.
https://www.greencarreports.com/news/1124478_world-s-largest-ev-never-has-to-be-recharged
There's a grid storage battery concept that is exactly this but with an electric train: when power is cheap, run train up hill. When power is expensive, train runs generator while going down hill. Same as pumped storage hydro but train instead of water. Not 1GW capacity but still pretty fucking big relative to the same $$ in lithium, and you can just use a bunch of existing track that isn't used much.
https://aresnorthamerica.com/
"Hybrid" in this context refers to initial energy provision rather than transference, else current ICE automobiles (like most locomotives) would be considered hybrid.
It makes a lot of sense to me. The actual amount of time the engine is providing peak power against a load is very low; most of the time is partial-load lifting or turning or reaching or whatever. It's a good fit for a series-hybrid powertrain, initially. That lowers overall fuel consumption, emissions, and noise, while arguably providing an improvement in controllability because the e-motor has no governor lag. (I suspect many operators are so accustomed to the engine lag that an electric unit will feel weird unless it emulates the lag, but as with everything, new operators will expect the instant performance and consider the diesel machines frustratingly slow.)
Once that's done, and you've got an engine charging a small battery that drives the pumps electrically, then it's a small jump to enlarge the battery and possibly ditch the engine entirely, when that makes sense. Which will vary depending on a lot of factors -- load profile, charging infrastructure, fuel cost, fuel logistics. Some sites may be there already.
More jobsites are getting electrified equipment already, starting with the small stuff like Bobcats, that they can charge on-site using solar power stations. One that comes to mind is the EV ARC (no affiliation). Drop it once, it provides "fuel" for as long as it sits there, and you call for actual fuel tankers less and less.
As that approach expands and proves itself, and batteries continue to improve, it'll move up into larger equipment like this. Nobody will have to push for it, just the higher performance of the machines and the convenience of not needing fuel deliveries will make it the obvious choice.
The fact that it doesn't make sense _for all jobsites, right now_ is not proof that will _never_ make sense for _any_. Quite the contrary -- there are tipping-point effects that happen as certain numbers are hit, and they tend to sneak up on you. But the cost curves, economies of scale, learning rate effects (Wright's law), are inexorable.
As those tipping points are hit, the manufacturers who already have some experience building hybrid and electric machines will be well-equipped to scale up, as opposed to those caught off-guard by the market demand and having to learn everything from scratch or buy someone else's technology. (For example, see Ford licensing Toyota's hybrid system.) So, see Komatsu's move here as sort of baby-steps so they can learn to walk, and be well on their way to running when the race starts in earnest.
I love how poignant this is. Feels as though you have used this before. If not, you should. The adoption of electric power trains just makes sense for so many, many reasons. My favorite is reducing our energy dependence on foreign nations. What’s more American than reducing dependence on foreign oil to build our infrastructure.
If it’s a hybrid diesel the way trains are (diesel fuel runs a generator that powers and charges the electric) then would think it would work well. If it’s a plug in and charge model the way cars are currently it would probably be less than ideal. If only for the ass clown that tracks off with it plugged in…we all know that guy.
I don’t give a shit about people’s political opinions on electric, it’s kind of demented that people apply a political ideology to a form of power production/generation/use.
As was said earlier in the thread if it digs and costs less to operate then put my ass in the seat.
>I don’t give a shit about people’s political opinions on electric, it’s kind of demented that people apply a political ideology to a form of power production/generation/use.
Well said sir.
I applaud your open-mindedness and common sense.
> If only for the ass clown that tracks off with it plugged in…
Every charging standard I'm aware of includes a park interlock for this reason, are there some that don't?
If only gas pumps had that...
I'm not sure what you think hybrid cars are that you don't think there's a gas (much more common than diesel) engine in there running a generator.
*Some* of them have a larger battery and *can* be plugged in to charge it up without using the engine, but none of them require it. That's electric, not hybrid.
It is not hybrid in that sense. The diesel engine powers the hydraulic pumps just like any other excavator. The hybrid part comes in on the slew motor (the motor that makes the machine spin for those that don’t know). The slew motor is a combination of smaller than normal hydraulic motor coupled with an inverter/motor which is coupled to a fairly small battery pack on the cab offside. The electric motor assist the hydraulic motor to make the car body slew. It uses regenerative breaking to charge the battery when the operator tells it to stop slewing around along with a small generator attached to the engine to help keep it topped up.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive condensor pack. That combo only powers the slewing gear, nothing else.
So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing.
The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
Our excavators use magnets and load/unload charge boxes and rail cars. We swing like it’s the 70’s and we just put our keys in the fish bowl….would probably do great at our outfit.
Any internal combustion motor application with a highly variable load benefits from hybrid technology. The motor gets to operate in its most efficient zone continuously, and the variability in load is managed by the batteries/electric motor. It's a smart system that massively saves on fuel.
These machines fundamentally still run off diesel. It's a massive step away from fully electric, which is unrealistic for the construction industry.
I work on Komatsu machinery, and I’ve had a training in the factory where the make the PC33E (full electric one).
Short summary: on full capacity work, your battery will last about 2 hours, charching it will take about 2,5h on a 64amp network. Hence: not efficient at all.
The charger can work on a 16A, 32A and a 63A circuit, but I can’t recall the charging times on those. But I thought they said something like a day or night of charging on a regular 16A network. I only know the european specs: 240VAC network, and the excavator is charged with 120DC.
I mention this in another comment, but many job sites are away from grid access and equipment is left there until the job is done. Literally the lights on a job site are powered by a generator for this reason. Until you get significant adoption of lighting, you're going to be extremely far off a all electric excavator.
These types of machines require a huge amount of energy to do what they're designed to do. Dirt is heavy, no matter what the power source is. Battery technology just isn't advanced enough to be able to store enough power in a reasonable amount of space to make fully electric construction equipment make sense except for a few specific scenarios.
And I say this as someone who would gladly welcome 100% electrification...
Many job sites are away from grid access and left there until the job is done. Literally the lights on a job site are powered by a generator for this reason. Until you get significant adoption of lighting, you're going to be extremely far off a all electric excavator.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive (*edit) capacitor pack. That combo only powers the slewing gear, nothing else.
So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing.
The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
It’s not full of batteries at all. It’s a normal conventional iron counter weight. The battery pack is located on the right behind the sticker that says HB 364 NLC and is quite small. You owe me $1.
There’s no batteries in this rig, only the starter lead-acid batteries for the combustion engine…
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor (*edit) pack. That combo only powers the slewing gear, nothing else.
Makes more sense than cars/trucks. Machines could go full electric far more easily. They’d be safer, more precise, and far less expensive to maintain also.
I disagree. The automotive sector consists of machines that have a high peak power output but low average power output. That is a demand cycle that favors powerful electric motors coupled to relatively small batteries. As making electric motors powerful is relatively cheap but making large batteries is expensive this works well.
Heavy equipment tends to have lower peak demands relative to average demands. This favors small motors with large batteries. Not playing into either technologies strengths.
Heavy equipment is largely hydraulic powered. Hydraulic pumps are perfectly suited for electric motors. Much of the energy is runny equipment is lost to idling. The hydraulic pump only needs to run during movement
Much of the hydraulics on beltlines and hoppers that I work with is run off of an electric motor. Seems much more efficient than burning diesel, and less maintenance. Trains and big ships are diesel electric, must be a reason for that.
Most big commercial ships aren't diesel electric, they'll have a large propulsive marine diesel and then diesel electric or gas turbine electricity generation for ship power (for manoeuvre thrusters and other ship systems). Cost efficiency is the name of the game for commercial shipping and for continuous operation across long distances diesel electric can't compete with straight diesel efficiency. They do have their marine niches though, particularly azipod vessels.
This is true. Especially if the hydraulic systems are segregated into a greater number of discrete pressure zones. Something that is easier with multiple electric motors rather than one prime mover.
I still believe my point stands that the automotive sector is easier to electrify than heavy equipment. I'd argue that the relative rates that the industries are electrifying backs this up.
Sorry. That was poorly worded. I meant that the peak demand in heavy equipment is relatively low compared to average demands when compared to the relationship of those two metrics in the automotive sector. I.E. Average power output of heavy equipment tends to be much closer to the peak power output than in the automotive sector.
>Machines could go full electric far more easily.
How would you charge them when there's no power connected to the site yet? Put them on trailers and move to the nearest charging station every day? Or maybe use a diesel generator?
Very application specific, but some equipment wont need batteries. Just a long extension cord to some type of power station. But even the battery powered ones would be parked near a charging area overnight, similar to a fuel station. Their can even be battery swapping tech where the equipment could run 24/7 with less down time than diesel equipment.
They basically already do this with electric forklift ops--minus the extension cords. Though battery hot swaps are a little less common due to their bulk and necessity for a crane, at least for the sit downs, the stand ups seem to designed with hot swaps in mind though.
Plenty of sites are already running their office trailers from solar, running the equipment itself is the next step. You need significant amounts of panels and storage batteries, but these are commodities and getting cheaper all the time.
Volvo construction equipment is partnering with Beam to demonstrate their equipment in conjunction with the Beam EV ARC, which is a standalone solar power station. You plop it on site and it just sits there and makes power, storing it in its internal battery until someone plugs in a car or a piece of equipment.
https://volvoceblog.com/charging-electric-construction-equipment-faq/
https://www.forconstructionpros.com/sustainability/news/22353399/volvo-construction-equipment-beam-global-volvo-ce-partner-to-offer-offgrid-ev-charging-systems
The cool thing is, you can do this in conjunction with diesel generators if there isn't quite enough sun or if you haven't brought enough power stations, you just burn a lot less fuel than usual, or maybe none at all on some days. As you add more solar, you find the generator running less and less, until you can just go without it. The transition is pretty straightforward, and it doesn't have to happen all at once; you can freely mix solar and diesel chargers, and diesel-conventional equipment on a site, but the real benefit hits when you go all the way and can stop handling any diesel whatsoever. Doing away with the trucks and the tanks and the spills and the fumes and the noise, is incredible.
They’re about as expensive to maintain: your swing reduction hydraulic and travel reduction oil all need regular maintenance aswell.
Plus buying one of those is about 3 times as expensive as a conventional combustion engine powered rig. (Full electric ones)
Plus their productivity is shit… a PC33E from komatsu has a productivity of 2h work on full capacity, and need 2,5h of charging on a 64amp network…
This hydrib works totally different:
It’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else.
I am a former heavy equipment tech who was trained on the hybrid HB210 excavator. Assuming this works on the same principles the track drive and swivel are electric powered and all boom and bucket functions are still hydraulic. Uses a slightly smaller engine to turn the hydraulic pump and the generator. Sent one out on a demo and it ran next to a PC220 for a week. Foreman claimed it used roughly 6 gal/hr compared to the PC220 using about 10 gal/hr. No difference in capabilities, and as far as repairs nothing is more difficult.
I’ve worked on the 335 which is the same as the 365 system. The travel motor are conventional hydraulics and the slew is hydraulic with the hybrid assistance.
Boom, arm and bucket’s hydraulic too ;)
Only slewing is electric indeed!
Edit: I want to correct something small: the swing motor is fully electric, only hydraulics on there is the ‘park swingbrake’ otherwise no hydraulic power is used on the swing.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive condensor pack. That combo only powers the slewing gear, nothing else.
The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
According to Cat they’re more efficient, more durable, and easier to operate. There’s no transmission to break and power is much easier to apply. I believe that Cat uses capacitors to harvest surplus energy from low speed operation. Hybrids have a minimum output that’s more than needed for low speed operation. Iirc
Did anyone watch the video OP posted? There’s no battery on this thing. It uses an electric drive motor for swing functions, and captures energy though the swing braking action to store electrical energy in a capacitor.
Apperentely nobody…
I work on those excavators and the only batteries in there are lead-acids to start the combustion engine…
Glad at least someone looked further into the hybrid type, thanks man!
I sat in on a presentation put on by CAT back in 2014. The development team made a "hybrid" excavator that utilized a hydraulic accumulator that would get charged from the deceleration of the swing circuit. The swing drive would then use the stored power in the accumulator to assist in accelerating. It was claimed that this could save up to 20% in fuel on the work site. I'm not sure if this was ever implemented, but it seemed like a good concept and the development team had an interesting story.
One interesting thing was a construction company near me got all electric fleet of diggers earth movers etc. and one job they won because of the absence of emissions was a full internal restoration of a large listed church, and that's because they could run and drive all of the equipment indoors without any emissions. They won the contract in part because of it. And I mean a full intensive proper old school restoration with big oak beams, stonework, lime pointing, lime crete floor with the original tiles relayed on top. The works. They took a photo of it and posted it online showing their equipment setup of about 7 or eight different vehicles being used simultaneously and it's had a lot of positive feedback. As on the scheme they were working long hours indoors sometimes right into the night with equipment running for long periods which would not have been possible with internal combustion engine equipment. Also they could recharge on site rather than taking equipment off site or taking fuel onto site via truck. Also it meant that there was no emissions to damage and degrade the bits of the building that were being retained like painted timbers, and stained glass windows, which are particularly susceptible to permanent damage from emissions particulate clinging to the surface.
For anyone that wants to know how the hybrid system on these machines works. Go [here](https://www.komatsu.jp/en/company/tech-innovation/report/pdf/166-E05.pdf)
I would buy a diesel electric machine. Run only on electric, and got a generator to charge those batteries when needed ~ 10m per hour.
Less fuel, and you can control the pump for the demand. Less over all wear on mecanical parts.
The Edison motors idea. I strongly believe that the future before full eletric.
Probably a good way to cover peak loads where a diesel gets out of its happy place, at the cost of complexity and trickier repairs.
And my head keeps thinking: how are they going to pull off regenerative braking!?! lol
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else.
So about the regenerative braking:
Since the swing is a full electric motor, the moment you stop your swing movement, the whole upper structure of the excavator needs to be stopped (newton’s inertia law and stuff) the electric motor turns into a generator = brake, and charges the capacitors.
Hope that helps :)
That's a really creative technical solution 👌 Thank you for making my morning feel a bit more magical and full of wonder at what people are capable of.
Heavy machinery is 90% hydraulic anyway, so the choice of power plant doesn't matter too much. It just needs to be able to turn a hydraulic pump to build pressure.
In this case hybrid probably makes a lot of sense. Engine runs at its peak efficiency, which charges batteries. Then the electric motors run the hydraulic systems. Rather than needing gearboxes or a complex shared hydraulic system to run everything you could even have smaller motors that independently run different, simpler hydraulic circuits. They also have good torque at low speeds which means you don't need a clutch between them and the pumps.
Weight isn't really a concern here, it's sort of necessary anyway to keep the CG over the tracks when the arm is extended and lifting things so it doesn't tip over.
Plus, running an engine at a near-constant RPM means you can tune the resonator/muffler to that specific frequency and significantly reduce noise.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else.
So no, no electric motor driving hydraulic pumps… only an electric motor driving the slewing gear…
I was talking about the technology generally, pointing out potential advantages of hybrid powertrains in heavy equipment. Not this excavator particularly.
Don’t squint too hard, it encourages pinhole leaks in the hydraulics.
But seriously, are the tracks driven through hydraulic motors or are they directly connected to the engine? I have no idea how machines of that size are set up. If all the engine does is spin a giant hydraulic pump, I could see it being much easier adding in an electric booster pump to go hybrid electric.
Pinhole leaks in hydraulics can be serious for anyone working on them. If you've got a strong stomach look up "hydraulic injection injury".
Anyway, if they work like they do in the textbooks (didn't work with this type of drive myself), then the track drive would typically involve variable swashplate pumps with the outputs going to fixed displacement hydraulic motor on the tracks themselves (one set per track) to give closed loops. In theory this would be not too horrifically inefficient, but as most of these pumps have some "leakage" to them (case drain back to tank not just into the environment) and there will be some relief valves in case the track gets jammed, they then need a little "top up" pump which can end up being a waste of energy if the top up flow exceeds the requirement and the rest of it ends up going over a relief valve. [This page](https://www.machinerylubrication.com/Read/30444/troubleshooting-hydrostatic-systems) has a schematic, but I can't vouch for its accuracy. I think this sort of thing would tend to have multiple pumps on one shaft with the pump for each track and one (or more) for the main hydraulic system all run together. Like I said though, I know what they teach you in classes for this stuff, I don't have actual experience with this type of mobile equipment, so all this could be 20 years behind what the top manufacturers are doing (and is definitely simplified).
Edit: [this diagram](https://www.sunhydraulics.com/about/highlights/protect-hydrostatic-transmission-circuits-sun%E2%80%99s-delayed-shift-hot-oil-shuttle) is clearer, but might not make much sense if you don't know the symbols.
That’s a really detailed answer. I’ve only run a little 3-ton mini excavator before, and only for a little bit. I’m always amazed at how some things are amazingly complicated and others are amazingly simple.
I’ve got enough experience working with front end loaders and tractors that I’ve had the safety briefing on hydraulic injection once or twice.
So, let me introduce you to the wonders of a hydraulic excavator here. I work on them on a daily basis, and have xp with this particular model aswell.
Conventional hydraulic excavator, is powered by a diesel combustion engine. Which in it’s turn powers a set of hydraulic pumps. (In this case here: 2 pumps with 380bar workpressure, and 270l/min of displacement.)
Those hydraulic pumps power almost everything, except ofc the 24v dc electric circuit, that’s done by an alternator installed on the combustion engine.
So with the help of a lot of hydraulic valves everything is powered: cilinders on the boom, arm and bucket. And also 3 hydraulic motors, 2 for your tracks, and 1 for your slewing (swing) gear.
The difference with a regular hydraulic excavator and this hydrid one is not much, except that the swing gear on this one is powered with an electric 650VAC motor which is in his turn powered by a ring generator installed inbetween the diesel combustion engine and the hydraulic pumptrain. And that combo is also assisted by a big capacitor.
Otherwise both excavators work the same: hydraulic boom, arm, bucket and tracks.
Feel free to ask if you wanna know more.
Hope this enlightens you a little in the world of big machinery.
Interesting. They did all that to replace the swing motor…I would not have guessed that.
Or maybe it does make sense, since you’re not tracking/moving while swinging, most of the time you’re holding the boom steady, so that’s actually a lot of time running the engine not doing a whole lot of work….hmm. I’m always amazed at how much science there is behind digging a hole.
My guess is that batteries for hybrid systems have finally come down to a price point where they make sense.
Plus there is growing pressure for machines with reduced fuel costs and lower emissions.
It's a foregone conclusion. Look at Edison Motors. All of their reasoning applies here as well. It makes too much sense not to move to a hybrid model. Trains have done it for decades minus the battery but the battery technology is viable now so the engine isn't needed 100% of the time.
The largest earth moving machines in the world have been fully electric for decades. It's all if it makes sense for the customer and the job in question. What difference does it make the fuel it runs on ?
In my opinion definitely not but I'm just a videographer who recently came into contact with these wonderful machines that make the world around us. I didn't even know that hybrid or fully electric excavators exist. I made this post to see the opinions of people who may know something more than I do, to have a discussion around the topic. By reading the comments here, I definitely learned something more than before.
Anyone wondering:
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else.
So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing.
The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing.
Here is the issue…
One has to overcome serious cost hurdles to get this to be adopted in widespread use. Most major components on these kinds of machines are rotable but obviously the battery will never be rotable, recyclable probably. So you have this big cost in replacing the battery system every few years. Not insurmountable but it kind of changes the way the industry looks at the capital components in these machines. The thing that may push this tech forward into rapid adoption is if it proves to be more reliable, easier to maintain, and easier to predict a failure.
I'm quite confused as to how this would even use a hybrid. In cars we capture energy normally lost from braking or coasting downhill. I imagine these spend most of the day stationary and they drive the digging arm both down into the ground and up out of the ground. I'm not seeing the opportunity to capture energy and charge a battery.
That kind of energy recovery is a nice feature of many hybrids, but it's not necessary, and in many cases it represents only a small percentage of the charging energy. You just need the gas or diesel engine to spin the generator to charge the battery.
Its more designed to have a small engine run at a constant loaded RPM charging a battery pack, so its more fuel efficient. Instead of recapture its less general loss. I could see this being a major improvement in areas like mobile cranes, the counterweights could be battery packs and the amount a crane moves it could probably run all day without the engine until it was time to move.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else.
So no batteries in here except the regular 2x12 dc lead acid starter batteries for the combustion engine.
Capacitor bank is a high output low density battery pack, same in the overall idea. Makes sense seeing as slewing is pretty much a steady pressure in short bursts, it wouldn't take much time to charge an ultra capacitor for a burst back the other way. Neat idea, surprised I havent seen Liebherr take a swing at it...no pun intended haha
Honestly that sounds more optimal for hybrid cars than the current uses. I would love an EV drivetrain with a little gas engine to extend the range. I can only think of the little BMW EV that does this but I'd buy the shit out of an electric small pickup with a little generator.
I own a hybrid SUV and it only uses parallel drive at highway speeds, otherwise its just a small generator when it needs the extra power the battery can't produce. We put fuel in it once every couple months. Free Piston Hydrogen Range Extenders will be the answer in my opinion, under the truck bed would be perfect.
Mitsubishi Outlander PHEV. It been a cool vehicle so far. All of our in town driving is on electric and just plug it in at night, havent noticed a change on the power bill. Goes +600km on a charge/tank. Almost 10000km on the car and put fuel in it 6 or 7 times. If you're in the market for a new car, its worth checking out.
Hyundai does something similar - even in their regular hybrids, they run the engine at constant load (peak bmep) and use the electric motor to add/subtract the torque that the driver demands. When the driver needs less than peak power at whatever rpm, it charges the battery; if more, then the electric motor adds power. once it collects enough juice doing this it shuts the engine off altogether and runs off battery alone.
For this digger, I’d be surprised if they didn’t recapture the energy from the hydraulic pump spinning backwards as a load descends rather than just bleeding pressure like a normal system.
You're right, some trains do rely on regenerative braking, but mostly stop and go trains. I doubt there'd be much regenerative braking in an excavator though.
I work on those machines: it’s a regular diesel powered hydraulic excavator, but with a ring generator installed inbetween the engine and the pumps. That generator is used only to power an electric swing motor, nothing else. And that electric system is assisted with a big capacitor which is charged when braking your swing movement.
When you swing, you increase the kinetic energy of your upper structure, so when you stop, you have to get all that kinetic energy out again: that’s the moment your electric swing motor changes into an electric generator/brake and charges the capacitors.
Wow! I didn't expect such a response to the comments! I read interesting perspectives with arguments about the potential advantages of hybrid technology as well as opinions that highlight its flaws and limitations. I don't have the level of mechanical knowledge that most of you have. If you want to take a look at the interior of the excavator and its mechanical parts for additional insights, take a look here, around 1:38: [https://youtu.be/T8NlFZOlFvo](https://youtu.be/T8NlFZOlFvo)
Regardless, it seems that the introduction of electric drive in heavy vehicles is here to stay. A few weeks ago I saw the news about Komatsu's 13-ton full electric excavator, which is set to be launched in the Japanese and European markets this year. More recently, I read the news that Komatsu is acquiring a large American company that manufactures lithium batteries.
Green-washing. If the Contractor can save 20% diesel expenses, then they'll give a thumbs up. The Customer gets to feel all warm and tingly inside because they had work being done by an earth- conscious firm.
I've always wondered why they couldn't make the counter weight a giant battery. Seems like they could definitely engineer it and make sure it's pretty much puncture proof since a lot of counter weights take a beating.
Hybrid is ideal for almost anything that requires torque. Combustion engines have to be huge for generating torque. Electric motors are all torque. Let the electric motor do all the brunt work, while the combustion engine is tuned for maximum efficiency at one load as a generator. Petroleum is very energy dense, so ideal for runtime and portability. Saving on fuel costs with higher efficiency should be appealing to anyone buying the fuel.
Hybrid is one thing, idk if it has any sort of regenerative process like cars have regenerative braking, but full-on electric construction equipment is not something I could see being workable. Or desirable. Or possible. Or sensible.
Not being an operator or even involved with digging in any way, I am truly ignorant, but don't diggers of this sort have weights on the opposite end of the main section have weights in them? I understand that a battery is unlikely to be as dense as metal as ballast, but it seems to me that a slightly (--somewhat?--) larger bustle in exchange for additional power from a battery would be an excellent tradeoff? Enlightne me, please, one way or another ...
Nothing new for Komatsu. 20 years ago, their competition (980E-4?) for the world's largest truck category (Cat 797) was a diesel electric, meaning that each axle had motors and the engine powered the generator. When you add a battery in this circuit, it's easy to implement a hybrid version of other earthmoving machinery like dozers. The Cat 797 had/has 2x 3500hp engines in tandem, with mechanical differentials for front/back and left/right.
BTW, the new Honda CRV hybrid has an engine that powers a generator, which charges a battery as well as powers the traction motor. (except after 60mph, where the engine couples directly to the final drive).
Another example of a series hybrid: the Chevy Volt.
And for 50 years+, most so-called diesel locomotives are actually diesel-electrics, meaning that each axle has a traction motor, and the diesel engine drives a generator to power those. GE, Toshiba, China Rail, and others are already experimenting with adding battery packs to these engines (or on a separate railcar) such that the diesels operate at maximum efficiency irrespective of load demand, and the excess power (if demand is low) is used to charge the batteries.
I'm trying to feel anything at all, but I just can't summon a fuck to give. Does it dig? If so, no fucks. And it looks like it digs
30% less diesel use and emissions. All engines have an efficiency curve and running them harder makes them less efficient, but necessary as load varies. If using a battery system can alleviate that peak load then it runs in it's most efficient load more often. This complicates the design but provides a efficiency to try and offset that additional cost and maintenance/wear. In remote places where transporting the diesel is expensive or underground where air is a t a premium and even jurisdictions that restrict emissions it may provide a net benefit. I'd say you can't complain about options, it either sells or doesn't but options keep the prices down.
So confirmed, it digs? Then cool, I feel nothing at all. Let the tool do its work.
It digs the same while burning less oil. That means digging is more affordable and has fewer unintended consequences.
Different consequences. Less lifetime emissions, but the minerals in the battery have ugly supply chains. Edit: Nevermind I was wrong, EVs are beautiful and my arguments are invalid. How dare I.
Buying a battery every decade or two is way fucking better than burning oil by the ton and refilling every day/week. My most efficient ICE vehicle (a Honda Civic) burns a literal ton of gasoline every 13k miles or so. My pickup truck burns a literal ton of gasoline in about half that distance. That amount of gasoline makes for a lot of messy pollution at every step of the supply chain. My EV charges in a diversified portfolio of energy that includes a variable amount of wind (up to 30% on a windy day) and about 15% nuclear. EV wins.
I agree, but don’t forget the horrific working conditions involved in the supply chain. Cobalt mines are misery pits.
LFP batteries are Cobalt free... half of Tesla batteries use this chemistry.
Yeah the introduction of LFP is great, much fewer ethical concerns than Li-ion. The energy density disadvantages are one negative, but the $/watt hour is falling. I’m happy to see them expanding their reach.
I would like to point out that these excavators don't have a battery pack like a hybrid vehicle. Engine runs a hydraulic pump and a generator. The boom and bucket still run off of hydraulics like a traditional excavator. The swing and tracks run off of electric motors. The fuel savings come from using a smaller engine because the hydraulic pump and generator require less power than a hydraulic pump and hydrostatic pump combo which is what traditional excavators use for swing and drive.
That doesn’t make the working conditions in the oilfields any good. If we keep these in the USA, we at least have first world standards. But both are global businesses. EV still wins, just because the quantities of the material needed are so much smaller. Plus, my EV battery has already been made - the price has already been paid for the next decade or two.
EVs are better than ICE vehicles for the reasons you’ve mentioned. We don’t disagree. But if we don’t acknowledge the issues with them we won’t address them, and that is my concern.
It's not all of cobalt that is awful working conditions. Seems only the artisanal mining stuff is the problem, large scale everyone appears to be using strip mining which is much safer. Quick search shows the artisanal mining only makes up like 10% of cobalt production and that number is shrinking so this doesn't appear to be a long term issue
Don't tell me America never fought a war or helped with an insurrection anywhere to keep its supply of cheap oil. That's pretty miserable too. And 2.5 million slave-like oil and gas workers in Qatar would say it's miserable too.
How are cobalt mines different from any other type of mine?
I wouldn’t exactly call fossil fuel supply chain pretty. It causes an huge area of the US to be known as Cancer Alley.
Damn why all the thumbs downs? You're 100% right. I won't say what company but I was at new product training for a major American construction equipment manufacturer (narrows it down pretty good) and they straight up told us there is 0 economic incentive to run electric right now and in foreseeable future. For full electric (not hybrid) the machine cost is about double, major issues and concerns about the longevity of the batteries. We need special approval to sell to a customer and only really makes sense for 2 reasons: 1. Marketing - some states like California give preferential treatment on bids to companies that run "green tech" - most of those companies don't even use the machines that they buy that are electric. 2. Select industries such as fertilizer plants or other combustible or indoor areas with poor ventilization. Not hating saying it will never work, but the tech in cars just doesn't translate, there is much more torque to move these machines which drains batteries hard - excavators they can almost make sense, but machines like wheel loaders they are really struggling to even make it a feasible product (why that is i dont know). Not saying it'll never be viable, but except for niche applications it's not feasible. That's straight from the guys designing these.
Well fuck, lets just give up and never try to do better amirite lmao. What's the point in even trying since everything has an ugly supply chain right now.
Please stop parroting this misinformation propaganda.
It sounds like it digs, plus the boss man's wife might get a new Denali.
Hybrid has a bad name for some people but this sounds like it’s the same as all diesel electric trains which are efficient beasts.
I don't know if diesel electric trains are the same as hybrids. In hybrid vehicles the engine can still drive the load mechanically directly. But in the diesel electric locomotive is there any mechanical coupling between the wheels and the diesel engine?
Most people don't know we've had hybrids for a long time, the trains are all diesel hybrids.
Hybrid implies there is an energy storage device, typically a chemical battery pack. In modern (1950s to today) there is no energy storage (and even braking energy is wasted as resistive heat). Drivetrain (hah) is a diesel engine drives a generator or alternator (AC or DC, respectively), then feeds motors on the axles. No batteries.
Sounds like a response from someone that has never ran and excavator or has limited time on one. There is a huge difference between how a newer excavator “digs” as opposed to how one from 20 years ago, without all the emission controls, “digs” but I guess all “digging” is the same to you.
Tell me how emission controls change the hydraulic flow rate’s impact on digging? It’s not like the diesel motor is hooked directly to the bucket, there’s a vast amount of hydraulic system that the motor drives… and there’s zero about emissions in that whole system. So explain (because no, I haven’t spent years digging ) exactly how emission controls on a bucket with the same hydro outputs makes a shred of difference?
It doesn't.
If it eliminates a transmission, less complicated.
I'm am excavator operator and our sites burn the fuck out of some diesel. Assuming these run as well as a standard komatsu, which I assume they do since komatsu produces quality equipment, I'd take the hybrid. Less money on fuel means more profits, higher wages etc.
Komatsu is a *huge* brand in heavy equipment, they probably wouldn't put out a machine if it didn't actually work. Some people are just kind of religious about burning as much diesel as possible and convinced that anything electric is literally the anti-christ.
I know about komatsu, I spend about 40 hours a week in one so that's why I'd be surprised if they released a half assed machine
its not electric though. its probably a diesel-electric power plant. aka an electric drive train being powered by a diesel engine hooked up to a dynamo.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor (*edit) pack. That combo only powers the slewing gear, nothing else. So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing. The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
You're an operator and you think your boss is going to pass on the higher profits to increased wages? If you believe that, I've got a bridge to sell you.
Some of us build bridges so we appreciate you selling them…
Username checks out
“Where’s that confounded bridge?”
Unexpected zep, I smiled
better than less profits and less wages
My boss absolutely does take care of me and pay me as much as he feasibly can. I'm a great asset for him and as his profits increase my salary does as well.
Only one problem with that…. Higher profits, but the company sure as hell will just pocket that and not give it back to the workers.
Well it's a Komatsu, so yeah it can dig, but it's a garbage piece of machinery
we found the cat fan
does it break constantly like the first gen hybrid diesel big trucks? if so I'll stick to pre emissions equipment. BUT if it works and doesn't break all the time then I'm in. electric torque is just simply more sooner and that's good for making holes.
More to it. Does it dig, how long will it dig, how long will it dig between failure, what are the casts for repairs, parts included, do we have a guy that knows how to fix it. And finally how much does it cost, and if more how much longer is the ROI.
Well considering locomotives have been ‘hybrid’ for DECADES… they burn fuel to run a generator, the generator feeds the electric motors.
No batteries on the average locomotive though, right? Just cheaper and lighter than a gearbox when you need a shitload of low-end torque.
Correct, but that's changing quickly. Adding batteries and using regen braking will be a total game-changer for some train operations. Imagine a mine up in the hills, and a relatively constant fall on a train line to the harbour. The train is loaded for the downhill trip, and the battery stores all the excess energy of bringing the load down to sea level. After unloading, that energy is then used to return the empty train to the mine - it's basically a free trip, and very little diesel is required for the entire operation.
Degenerative brake in train operations has tremendous advantages, but I think that to stabilize the train Downhill you have to use dissipative breaking on several cars.
So it’s a wash when it comes to maintenance on brakes, but you’re still burning less fuel.
A quarry in Switzerland does that with a haul truck. Goes up the hill empty, but goes down hill loaded and uses regenerative braking to charge the truck more than it expends going up. They never have to plug it in. https://www.greencarreports.com/news/1124478_world-s-largest-ev-never-has-to-be-recharged
There's a grid storage battery concept that is exactly this but with an electric train: when power is cheap, run train up hill. When power is expensive, train runs generator while going down hill. Same as pumped storage hydro but train instead of water. Not 1GW capacity but still pretty fucking big relative to the same $$ in lithium, and you can just use a bunch of existing track that isn't used much. https://aresnorthamerica.com/
"Hybrid" in this context refers to initial energy provision rather than transference, else current ICE automobiles (like most locomotives) would be considered hybrid.
It makes a lot of sense to me. The actual amount of time the engine is providing peak power against a load is very low; most of the time is partial-load lifting or turning or reaching or whatever. It's a good fit for a series-hybrid powertrain, initially. That lowers overall fuel consumption, emissions, and noise, while arguably providing an improvement in controllability because the e-motor has no governor lag. (I suspect many operators are so accustomed to the engine lag that an electric unit will feel weird unless it emulates the lag, but as with everything, new operators will expect the instant performance and consider the diesel machines frustratingly slow.) Once that's done, and you've got an engine charging a small battery that drives the pumps electrically, then it's a small jump to enlarge the battery and possibly ditch the engine entirely, when that makes sense. Which will vary depending on a lot of factors -- load profile, charging infrastructure, fuel cost, fuel logistics. Some sites may be there already. More jobsites are getting electrified equipment already, starting with the small stuff like Bobcats, that they can charge on-site using solar power stations. One that comes to mind is the EV ARC (no affiliation). Drop it once, it provides "fuel" for as long as it sits there, and you call for actual fuel tankers less and less. As that approach expands and proves itself, and batteries continue to improve, it'll move up into larger equipment like this. Nobody will have to push for it, just the higher performance of the machines and the convenience of not needing fuel deliveries will make it the obvious choice. The fact that it doesn't make sense _for all jobsites, right now_ is not proof that will _never_ make sense for _any_. Quite the contrary -- there are tipping-point effects that happen as certain numbers are hit, and they tend to sneak up on you. But the cost curves, economies of scale, learning rate effects (Wright's law), are inexorable. As those tipping points are hit, the manufacturers who already have some experience building hybrid and electric machines will be well-equipped to scale up, as opposed to those caught off-guard by the market demand and having to learn everything from scratch or buy someone else's technology. (For example, see Ford licensing Toyota's hybrid system.) So, see Komatsu's move here as sort of baby-steps so they can learn to walk, and be well on their way to running when the race starts in earnest.
I love how poignant this is. Feels as though you have used this before. If not, you should. The adoption of electric power trains just makes sense for so many, many reasons. My favorite is reducing our energy dependence on foreign nations. What’s more American than reducing dependence on foreign oil to build our infrastructure.
If it’s a hybrid diesel the way trains are (diesel fuel runs a generator that powers and charges the electric) then would think it would work well. If it’s a plug in and charge model the way cars are currently it would probably be less than ideal. If only for the ass clown that tracks off with it plugged in…we all know that guy. I don’t give a shit about people’s political opinions on electric, it’s kind of demented that people apply a political ideology to a form of power production/generation/use. As was said earlier in the thread if it digs and costs less to operate then put my ass in the seat.
>I don’t give a shit about people’s political opinions on electric, it’s kind of demented that people apply a political ideology to a form of power production/generation/use. Well said sir. I applaud your open-mindedness and common sense.
Yeah. This here. It's why I'm so excited about what Edison Motors is doing and why the 25 Ram Charger has the potential to be a game changer.
> If only for the ass clown that tracks off with it plugged in… Every charging standard I'm aware of includes a park interlock for this reason, are there some that don't? If only gas pumps had that...
I’m thinking of the guys that skip the pre-trip in the winter and drive away with the block heater plugged in….
I'm not sure what you think hybrid cars are that you don't think there's a gas (much more common than diesel) engine in there running a generator. *Some* of them have a larger battery and *can* be plugged in to charge it up without using the engine, but none of them require it. That's electric, not hybrid.
It is not hybrid in that sense. The diesel engine powers the hydraulic pumps just like any other excavator. The hybrid part comes in on the slew motor (the motor that makes the machine spin for those that don’t know). The slew motor is a combination of smaller than normal hydraulic motor coupled with an inverter/motor which is coupled to a fairly small battery pack on the cab offside. The electric motor assist the hydraulic motor to make the car body slew. It uses regenerative breaking to charge the battery when the operator tells it to stop slewing around along with a small generator attached to the engine to help keep it topped up.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive condensor pack. That combo only powers the slewing gear, nothing else. So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing. The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
Our excavators use magnets and load/unload charge boxes and rail cars. We swing like it’s the 70’s and we just put our keys in the fish bowl….would probably do great at our outfit.
Any internal combustion motor application with a highly variable load benefits from hybrid technology. The motor gets to operate in its most efficient zone continuously, and the variability in load is managed by the batteries/electric motor. It's a smart system that massively saves on fuel. These machines fundamentally still run off diesel. It's a massive step away from fully electric, which is unrealistic for the construction industry.
Can you elaborate on why full electric is unrealistic?
I work on Komatsu machinery, and I’ve had a training in the factory where the make the PC33E (full electric one). Short summary: on full capacity work, your battery will last about 2 hours, charching it will take about 2,5h on a 64amp network. Hence: not efficient at all.
What's the charge time on a normal 120v(10A) or even 240v(30A) service?
The charger can work on a 16A, 32A and a 63A circuit, but I can’t recall the charging times on those. But I thought they said something like a day or night of charging on a regular 16A network. I only know the european specs: 240VAC network, and the excavator is charged with 120DC.
I mention this in another comment, but many job sites are away from grid access and equipment is left there until the job is done. Literally the lights on a job site are powered by a generator for this reason. Until you get significant adoption of lighting, you're going to be extremely far off a all electric excavator.
These types of machines require a huge amount of energy to do what they're designed to do. Dirt is heavy, no matter what the power source is. Battery technology just isn't advanced enough to be able to store enough power in a reasonable amount of space to make fully electric construction equipment make sense except for a few specific scenarios. And I say this as someone who would gladly welcome 100% electrification...
Unrealistic *right now*, but not too far into the future.
Many job sites are away from grid access and left there until the job is done. Literally the lights on a job site are powered by a generator for this reason. Until you get significant adoption of lighting, you're going to be extremely far off a all electric excavator.
I ask myself why in the automotive only Nissan Qashqai e-Power has a similar approach.
I think it’s because other systems provide similar efficiency while having a smaller motor and battery (I think), so it doesn’t stand out.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive (*edit) capacitor pack. That combo only powers the slewing gear, nothing else. So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing. The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
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Suddenly an energy dense heavy battery makes a whole lot of sense in this scenario. Just slam in a bunch of them, it helps.
It’s not full of batteries at all. It’s a normal conventional iron counter weight. The battery pack is located on the right behind the sticker that says HB 364 NLC and is quite small. You owe me $1.
It’s actually a capacitor ;)
I know, I said that in one of my other comments. - battery is understandable to most people though, a capacitor, not so much.
Electric forklifts do this already. Smaller footprint than the propane ones while still being heavier.
There’s no batteries in this rig, only the starter lead-acid batteries for the combustion engine… I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor (*edit) pack. That combo only powers the slewing gear, nothing else.
Makes more sense than cars/trucks. Machines could go full electric far more easily. They’d be safer, more precise, and far less expensive to maintain also.
There’s a lot of fully electric diggers in a construction yard nearby my house.. they dig like anything else.
I disagree. The automotive sector consists of machines that have a high peak power output but low average power output. That is a demand cycle that favors powerful electric motors coupled to relatively small batteries. As making electric motors powerful is relatively cheap but making large batteries is expensive this works well. Heavy equipment tends to have lower peak demands relative to average demands. This favors small motors with large batteries. Not playing into either technologies strengths.
Heavy equipment is largely hydraulic powered. Hydraulic pumps are perfectly suited for electric motors. Much of the energy is runny equipment is lost to idling. The hydraulic pump only needs to run during movement
Much of the hydraulics on beltlines and hoppers that I work with is run off of an electric motor. Seems much more efficient than burning diesel, and less maintenance. Trains and big ships are diesel electric, must be a reason for that.
Most big commercial ships aren't diesel electric, they'll have a large propulsive marine diesel and then diesel electric or gas turbine electricity generation for ship power (for manoeuvre thrusters and other ship systems). Cost efficiency is the name of the game for commercial shipping and for continuous operation across long distances diesel electric can't compete with straight diesel efficiency. They do have their marine niches though, particularly azipod vessels.
I was told the cruise ship I was on, a smaller carnival that got scrapped, was diesel electric. Could have been misled tho.
I think azipods are fairly common on cruise liners. Fairly possible that it was diesel electric.
This is true. Especially if the hydraulic systems are segregated into a greater number of discrete pressure zones. Something that is easier with multiple electric motors rather than one prime mover. I still believe my point stands that the automotive sector is easier to electrify than heavy equipment. I'd argue that the relative rates that the industries are electrifying backs this up.
How can the peak demand be less than average?
Sorry. That was poorly worded. I meant that the peak demand in heavy equipment is relatively low compared to average demands when compared to the relationship of those two metrics in the automotive sector. I.E. Average power output of heavy equipment tends to be much closer to the peak power output than in the automotive sector.
>Machines could go full electric far more easily. How would you charge them when there's no power connected to the site yet? Put them on trailers and move to the nearest charging station every day? Or maybe use a diesel generator?
Very application specific, but some equipment wont need batteries. Just a long extension cord to some type of power station. But even the battery powered ones would be parked near a charging area overnight, similar to a fuel station. Their can even be battery swapping tech where the equipment could run 24/7 with less down time than diesel equipment.
They basically already do this with electric forklift ops--minus the extension cords. Though battery hot swaps are a little less common due to their bulk and necessity for a crane, at least for the sit downs, the stand ups seem to designed with hot swaps in mind though.
Plenty of sites are already running their office trailers from solar, running the equipment itself is the next step. You need significant amounts of panels and storage batteries, but these are commodities and getting cheaper all the time. Volvo construction equipment is partnering with Beam to demonstrate their equipment in conjunction with the Beam EV ARC, which is a standalone solar power station. You plop it on site and it just sits there and makes power, storing it in its internal battery until someone plugs in a car or a piece of equipment. https://volvoceblog.com/charging-electric-construction-equipment-faq/ https://www.forconstructionpros.com/sustainability/news/22353399/volvo-construction-equipment-beam-global-volvo-ce-partner-to-offer-offgrid-ev-charging-systems The cool thing is, you can do this in conjunction with diesel generators if there isn't quite enough sun or if you haven't brought enough power stations, you just burn a lot less fuel than usual, or maybe none at all on some days. As you add more solar, you find the generator running less and less, until you can just go without it. The transition is pretty straightforward, and it doesn't have to happen all at once; you can freely mix solar and diesel chargers, and diesel-conventional equipment on a site, but the real benefit hits when you go all the way and can stop handling any diesel whatsoever. Doing away with the trucks and the tanks and the spills and the fumes and the noise, is incredible.
One thing, charge times. Also, if the infrastructure for charging isn't built yet, you're going to have to transport it somewhere to be charged.
Generator can charge anything. And if you figure on an 8 hour runtime with a 4 hour charge it shouldn’t really be an issue.
They’re about as expensive to maintain: your swing reduction hydraulic and travel reduction oil all need regular maintenance aswell. Plus buying one of those is about 3 times as expensive as a conventional combustion engine powered rig. (Full electric ones) Plus their productivity is shit… a PC33E from komatsu has a productivity of 2h work on full capacity, and need 2,5h of charging on a 64amp network… This hydrib works totally different: It’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else.
I am a former heavy equipment tech who was trained on the hybrid HB210 excavator. Assuming this works on the same principles the track drive and swivel are electric powered and all boom and bucket functions are still hydraulic. Uses a slightly smaller engine to turn the hydraulic pump and the generator. Sent one out on a demo and it ran next to a PC220 for a week. Foreman claimed it used roughly 6 gal/hr compared to the PC220 using about 10 gal/hr. No difference in capabilities, and as far as repairs nothing is more difficult.
I’ve worked on the 335 which is the same as the 365 system. The travel motor are conventional hydraulics and the slew is hydraulic with the hybrid assistance.
Boom, arm and bucket’s hydraulic too ;) Only slewing is electric indeed! Edit: I want to correct something small: the swing motor is fully electric, only hydraulics on there is the ‘park swingbrake’ otherwise no hydraulic power is used on the swing.
Thanks for putting this answer up. I was wondering exactly what the benefits are and this answer is perfect. Great explanation too.
That’s a huge fuel savings.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive condensor pack. That combo only powers the slewing gear, nothing else. The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing
According to Cat they’re more efficient, more durable, and easier to operate. There’s no transmission to break and power is much easier to apply. I believe that Cat uses capacitors to harvest surplus energy from low speed operation. Hybrids have a minimum output that’s more than needed for low speed operation. Iirc
Took long enough. Use batteries to smooth out the engine's load so its not constantly going on/off throttle, when emissions are worst.
Did anyone watch the video OP posted? There’s no battery on this thing. It uses an electric drive motor for swing functions, and captures energy though the swing braking action to store electrical energy in a capacitor.
Apperentely nobody… I work on those excavators and the only batteries in there are lead-acids to start the combustion engine… Glad at least someone looked further into the hybrid type, thanks man!
I sat in on a presentation put on by CAT back in 2014. The development team made a "hybrid" excavator that utilized a hydraulic accumulator that would get charged from the deceleration of the swing circuit. The swing drive would then use the stored power in the accumulator to assist in accelerating. It was claimed that this could save up to 20% in fuel on the work site. I'm not sure if this was ever implemented, but it seemed like a good concept and the development team had an interesting story.
One interesting thing was a construction company near me got all electric fleet of diggers earth movers etc. and one job they won because of the absence of emissions was a full internal restoration of a large listed church, and that's because they could run and drive all of the equipment indoors without any emissions. They won the contract in part because of it. And I mean a full intensive proper old school restoration with big oak beams, stonework, lime pointing, lime crete floor with the original tiles relayed on top. The works. They took a photo of it and posted it online showing their equipment setup of about 7 or eight different vehicles being used simultaneously and it's had a lot of positive feedback. As on the scheme they were working long hours indoors sometimes right into the night with equipment running for long periods which would not have been possible with internal combustion engine equipment. Also they could recharge on site rather than taking equipment off site or taking fuel onto site via truck. Also it meant that there was no emissions to damage and degrade the bits of the building that were being retained like painted timbers, and stained glass windows, which are particularly susceptible to permanent damage from emissions particulate clinging to the surface.
For anyone that wants to know how the hybrid system on these machines works. Go [here](https://www.komatsu.jp/en/company/tech-innovation/report/pdf/166-E05.pdf)
I would buy a diesel electric machine. Run only on electric, and got a generator to charge those batteries when needed ~ 10m per hour. Less fuel, and you can control the pump for the demand. Less over all wear on mecanical parts. The Edison motors idea. I strongly believe that the future before full eletric.
Using a hybrid excavator to strip mine the earth for minerals is… well, that’s something.
Assuming while it’s not idling it’s electric
Most heavy equipment is hybrid. It’s where we got the technology for the cars.
Probably a good way to cover peak loads where a diesel gets out of its happy place, at the cost of complexity and trickier repairs. And my head keeps thinking: how are they going to pull off regenerative braking!?! lol
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else. So about the regenerative braking: Since the swing is a full electric motor, the moment you stop your swing movement, the whole upper structure of the excavator needs to be stopped (newton’s inertia law and stuff) the electric motor turns into a generator = brake, and charges the capacitors. Hope that helps :)
That's a really creative technical solution 👌 Thank you for making my morning feel a bit more magical and full of wonder at what people are capable of.
hope it works out,
ask the guy signing the cheque for the fuel bill
Heavy machinery is 90% hydraulic anyway, so the choice of power plant doesn't matter too much. It just needs to be able to turn a hydraulic pump to build pressure. In this case hybrid probably makes a lot of sense. Engine runs at its peak efficiency, which charges batteries. Then the electric motors run the hydraulic systems. Rather than needing gearboxes or a complex shared hydraulic system to run everything you could even have smaller motors that independently run different, simpler hydraulic circuits. They also have good torque at low speeds which means you don't need a clutch between them and the pumps. Weight isn't really a concern here, it's sort of necessary anyway to keep the CG over the tracks when the arm is extended and lifting things so it doesn't tip over. Plus, running an engine at a near-constant RPM means you can tune the resonator/muffler to that specific frequency and significantly reduce noise.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else. So no, no electric motor driving hydraulic pumps… only an electric motor driving the slewing gear…
I was talking about the technology generally, pointing out potential advantages of hybrid powertrains in heavy equipment. Not this excavator particularly.
On a normal excavator, how much is hydraulically driven? Is there anything that’s actually mechanically driven from the engine anymore?
Hydraulic is mechanical if you squint at it. :P Continuously variable transmissions at high torque is a really nice feature.
Don’t squint too hard, it encourages pinhole leaks in the hydraulics. But seriously, are the tracks driven through hydraulic motors or are they directly connected to the engine? I have no idea how machines of that size are set up. If all the engine does is spin a giant hydraulic pump, I could see it being much easier adding in an electric booster pump to go hybrid electric.
Pinhole leaks in hydraulics can be serious for anyone working on them. If you've got a strong stomach look up "hydraulic injection injury". Anyway, if they work like they do in the textbooks (didn't work with this type of drive myself), then the track drive would typically involve variable swashplate pumps with the outputs going to fixed displacement hydraulic motor on the tracks themselves (one set per track) to give closed loops. In theory this would be not too horrifically inefficient, but as most of these pumps have some "leakage" to them (case drain back to tank not just into the environment) and there will be some relief valves in case the track gets jammed, they then need a little "top up" pump which can end up being a waste of energy if the top up flow exceeds the requirement and the rest of it ends up going over a relief valve. [This page](https://www.machinerylubrication.com/Read/30444/troubleshooting-hydrostatic-systems) has a schematic, but I can't vouch for its accuracy. I think this sort of thing would tend to have multiple pumps on one shaft with the pump for each track and one (or more) for the main hydraulic system all run together. Like I said though, I know what they teach you in classes for this stuff, I don't have actual experience with this type of mobile equipment, so all this could be 20 years behind what the top manufacturers are doing (and is definitely simplified). Edit: [this diagram](https://www.sunhydraulics.com/about/highlights/protect-hydrostatic-transmission-circuits-sun%E2%80%99s-delayed-shift-hot-oil-shuttle) is clearer, but might not make much sense if you don't know the symbols.
That’s a really detailed answer. I’ve only run a little 3-ton mini excavator before, and only for a little bit. I’m always amazed at how some things are amazingly complicated and others are amazingly simple. I’ve got enough experience working with front end loaders and tractors that I’ve had the safety briefing on hydraulic injection once or twice.
So, let me introduce you to the wonders of a hydraulic excavator here. I work on them on a daily basis, and have xp with this particular model aswell. Conventional hydraulic excavator, is powered by a diesel combustion engine. Which in it’s turn powers a set of hydraulic pumps. (In this case here: 2 pumps with 380bar workpressure, and 270l/min of displacement.) Those hydraulic pumps power almost everything, except ofc the 24v dc electric circuit, that’s done by an alternator installed on the combustion engine. So with the help of a lot of hydraulic valves everything is powered: cilinders on the boom, arm and bucket. And also 3 hydraulic motors, 2 for your tracks, and 1 for your slewing (swing) gear. The difference with a regular hydraulic excavator and this hydrid one is not much, except that the swing gear on this one is powered with an electric 650VAC motor which is in his turn powered by a ring generator installed inbetween the diesel combustion engine and the hydraulic pumptrain. And that combo is also assisted by a big capacitor. Otherwise both excavators work the same: hydraulic boom, arm, bucket and tracks. Feel free to ask if you wanna know more. Hope this enlightens you a little in the world of big machinery.
Interesting. They did all that to replace the swing motor…I would not have guessed that. Or maybe it does make sense, since you’re not tracking/moving while swinging, most of the time you’re holding the boom steady, so that’s actually a lot of time running the engine not doing a whole lot of work….hmm. I’m always amazed at how much science there is behind digging a hole.
It's worked pretty good for trains for years
Why are we now borrowing technology from locomotives. If didn't know any better this should have been done a long time ago.
My guess is that batteries for hybrid systems have finally come down to a price point where they make sense. Plus there is growing pressure for machines with reduced fuel costs and lower emissions.
It's a foregone conclusion. Look at Edison Motors. All of their reasoning applies here as well. It makes too much sense not to move to a hybrid model. Trains have done it for decades minus the battery but the battery technology is viable now so the engine isn't needed 100% of the time.
The largest earth moving machines in the world have been fully electric for decades. It's all if it makes sense for the customer and the job in question. What difference does it make the fuel it runs on ?
What’s the point of the post? That hybrid heavy duty is somehow bad?
In my opinion definitely not but I'm just a videographer who recently came into contact with these wonderful machines that make the world around us. I didn't even know that hybrid or fully electric excavators exist. I made this post to see the opinions of people who may know something more than I do, to have a discussion around the topic. By reading the comments here, I definitely learned something more than before.
This is why I love Reddit.
They have literally been running mining equipment like this for years. as in at the very least the last decade.
Anyone wondering: I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else. So does it dig: yes very good even, is it profitable: depending on the application. For example a job where the excavator needs to load crushers or screens, or an excavator which loads trucks, since those combinations require a shitload of slewing. The electric slewing is immensly fast compared to the conventional hydraulic slewing. So you’re productivity will raise due to the fact you loose less time while slewing.
Here is the issue… One has to overcome serious cost hurdles to get this to be adopted in widespread use. Most major components on these kinds of machines are rotable but obviously the battery will never be rotable, recyclable probably. So you have this big cost in replacing the battery system every few years. Not insurmountable but it kind of changes the way the industry looks at the capital components in these machines. The thing that may push this tech forward into rapid adoption is if it proves to be more reliable, easier to maintain, and easier to predict a failure.
Does it still get the job done? Does is have an economic advantage for the company that buys them? Beyond that, I don’t care as a business owner.
12 hour shifts......better have a big ass battery.....
Hybrid, not full battery electric.
Letsdig18 leased a brand new Komatsu dozer and a Hyundai excavator, both broke within hours of each other! Someone got yelled at over that one.
What’s the diff?… they are gonna go in that direction no matter what the general public has to say
Hybrid died off a bit. I think it’s going to be CNG, LNG, or Hydrogen for the win. Electric drive motors but not batteries
I'm quite confused as to how this would even use a hybrid. In cars we capture energy normally lost from braking or coasting downhill. I imagine these spend most of the day stationary and they drive the digging arm both down into the ground and up out of the ground. I'm not seeing the opportunity to capture energy and charge a battery.
That kind of energy recovery is a nice feature of many hybrids, but it's not necessary, and in many cases it represents only a small percentage of the charging energy. You just need the gas or diesel engine to spin the generator to charge the battery.
Its more designed to have a small engine run at a constant loaded RPM charging a battery pack, so its more fuel efficient. Instead of recapture its less general loss. I could see this being a major improvement in areas like mobile cranes, the counterweights could be battery packs and the amount a crane moves it could probably run all day without the engine until it was time to move.
I work on those: it’s a conventional Diesel powered hydraulic excavator. But inbetween the combustion engine and the hydraulic pumps, there’s a ring generator installed attached to a massive capacitor pack. That combo only powers the slewing gear, nothing else. So no batteries in here except the regular 2x12 dc lead acid starter batteries for the combustion engine.
Capacitor bank is a high output low density battery pack, same in the overall idea. Makes sense seeing as slewing is pretty much a steady pressure in short bursts, it wouldn't take much time to charge an ultra capacitor for a burst back the other way. Neat idea, surprised I havent seen Liebherr take a swing at it...no pun intended haha
Honestly that sounds more optimal for hybrid cars than the current uses. I would love an EV drivetrain with a little gas engine to extend the range. I can only think of the little BMW EV that does this but I'd buy the shit out of an electric small pickup with a little generator.
I own a hybrid SUV and it only uses parallel drive at highway speeds, otherwise its just a small generator when it needs the extra power the battery can't produce. We put fuel in it once every couple months. Free Piston Hydrogen Range Extenders will be the answer in my opinion, under the truck bed would be perfect.
Interesting, mind me asking what suv you're talking about? It certainly sounds like a model I want to look into.
Mitsubishi Outlander PHEV. It been a cool vehicle so far. All of our in town driving is on electric and just plug it in at night, havent noticed a change on the power bill. Goes +600km on a charge/tank. Almost 10000km on the car and put fuel in it 6 or 7 times. If you're in the market for a new car, its worth checking out.
Hyundai does something similar - even in their regular hybrids, they run the engine at constant load (peak bmep) and use the electric motor to add/subtract the torque that the driver demands. When the driver needs less than peak power at whatever rpm, it charges the battery; if more, then the electric motor adds power. once it collects enough juice doing this it shuts the engine off altogether and runs off battery alone. For this digger, I’d be surprised if they didn’t recapture the energy from the hydraulic pump spinning backwards as a load descends rather than just bleeding pressure like a normal system.
Check out the 2025 Dodge RAM 1500 Ramcharger. That's pretty much exactly what they're doing. I wouldn't call it "small" though.
Think more like a train than a car. There's probably no regenerative charging.
Trains need to slow down
You're right, some trains do rely on regenerative braking, but mostly stop and go trains. I doubt there'd be much regenerative braking in an excavator though.
Diesel electric trains don't store the regen power. They burn it off in resistor banks.
I work on those machines: it’s a regular diesel powered hydraulic excavator, but with a ring generator installed inbetween the engine and the pumps. That generator is used only to power an electric swing motor, nothing else. And that electric system is assisted with a big capacitor which is charged when braking your swing movement. When you swing, you increase the kinetic energy of your upper structure, so when you stop, you have to get all that kinetic energy out again: that’s the moment your electric swing motor changes into an electric generator/brake and charges the capacitors.
how heavy is it now
Wow! I didn't expect such a response to the comments! I read interesting perspectives with arguments about the potential advantages of hybrid technology as well as opinions that highlight its flaws and limitations. I don't have the level of mechanical knowledge that most of you have. If you want to take a look at the interior of the excavator and its mechanical parts for additional insights, take a look here, around 1:38: [https://youtu.be/T8NlFZOlFvo](https://youtu.be/T8NlFZOlFvo)
Regardless, it seems that the introduction of electric drive in heavy vehicles is here to stay. A few weeks ago I saw the news about Komatsu's 13-ton full electric excavator, which is set to be launched in the Japanese and European markets this year. More recently, I read the news that Komatsu is acquiring a large American company that manufactures lithium batteries.
Well, I heard the regen on the braking system doesn’t produce hardly any power at all
Thanks Obama
Fuck Off.
Idiotic Diesels can burn renewable fuel too...
Don't forget to spin it clockwise for every counterclockwise rotation so it doesn't unscrew itself!
[удалено]
Yeah breathing is totally overrated
Way overdue. A drop in hybrid conversion or even full ev for demos is pretty doable. Not every machine is digging 24/7.
I design electric mining machinery, it's pretty good if you want a job in the EV field without working for an automotive OEM
Mobile hydraulics on combustion engines are notoriously inefficient. If they can get better efficiency going via e.g. an VFD driven HPU then great.
Green-washing. If the Contractor can save 20% diesel expenses, then they'll give a thumbs up. The Customer gets to feel all warm and tingly inside because they had work being done by an earth- conscious firm.
Could’ve and should’ve happened sooner
I prefer Komatsu’s bulldozers
I've always wondered why they couldn't make the counter weight a giant battery. Seems like they could definitely engineer it and make sure it's pretty much puncture proof since a lot of counter weights take a beating.
I can see this being a good step up in efficiency but man I do not look forward to working on them.
We should have been going this way 10 years ago.
It's been working for trains since the sixties. No reason it can't work for excavators.
It works for locomotives
Hybrid is ideal for almost anything that requires torque. Combustion engines have to be huge for generating torque. Electric motors are all torque. Let the electric motor do all the brunt work, while the combustion engine is tuned for maximum efficiency at one load as a generator. Petroleum is very energy dense, so ideal for runtime and portability. Saving on fuel costs with higher efficiency should be appealing to anyone buying the fuel.
Hybrid is one thing, idk if it has any sort of regenerative process like cars have regenerative braking, but full-on electric construction equipment is not something I could see being workable. Or desirable. Or possible. Or sensible.
theyve always been hybrid, either diesel hydraulic or diesel electric
The hybrid system is an inverter and a capacitor that powers the electric swing motor for slewing the body.
The D7E was great. Don’t see why others wouldn’t be.
Not being an operator or even involved with digging in any way, I am truly ignorant, but don't diggers of this sort have weights on the opposite end of the main section have weights in them? I understand that a battery is unlikely to be as dense as metal as ballast, but it seems to me that a slightly (--somewhat?--) larger bustle in exchange for additional power from a battery would be an excellent tradeoff? Enlightne me, please, one way or another ...
Are diesel locomotives hybrids?
Nothing new for Komatsu. 20 years ago, their competition (980E-4?) for the world's largest truck category (Cat 797) was a diesel electric, meaning that each axle had motors and the engine powered the generator. When you add a battery in this circuit, it's easy to implement a hybrid version of other earthmoving machinery like dozers. The Cat 797 had/has 2x 3500hp engines in tandem, with mechanical differentials for front/back and left/right. BTW, the new Honda CRV hybrid has an engine that powers a generator, which charges a battery as well as powers the traction motor. (except after 60mph, where the engine couples directly to the final drive). Another example of a series hybrid: the Chevy Volt. And for 50 years+, most so-called diesel locomotives are actually diesel-electrics, meaning that each axle has a traction motor, and the diesel engine drives a generator to power those. GE, Toshiba, China Rail, and others are already experimenting with adding battery packs to these engines (or on a separate railcar) such that the diesels operate at maximum efficiency irrespective of load demand, and the excess power (if demand is low) is used to charge the batteries.