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Eberspächer introducing diesel fuel-cell APU at IAA; planned market introduction in US in 2017

Basic elements and operating principle of the diesel fuel-cell APU. Click to enlarge.

At the upcoming IAA in Hanover, automotive supplier Eberspächer is presenting a fuel-cell APU (auxiliary power unit) for commercial trucks that converts diesel efficiently to electricity and thereby supplies the required power to all on-board consumer components such as the air-conditioning system or the refrigerator units.

As a result, the load for electricity generation can be taken off the engine or generator with a resulting decrease in fuel consumption and emissions. In future generations of trucks, components still driven mechanically today could thus be powered electrically at considerably less expense, the company suggests.

Currently, the need for auxiliary power is usually met on the road via a generator. In stationary periods, a diesel auxiliary power unit or, in the worst case, the idling engine takes over the supply of on-board electricity and air-conditioning. The diesel-engine APU usually drives the air-conditioning compressor mechanically via a belt and produces electricity.

Eberspächer’s fuel-cell APU generates electrical power without mechanical power losses from the diesel in the truck tank quietly with NOx, carbon monoxide and soot particulate emissions 90% less compared with a diesel-engine APU. The control electronics limit electricity production to what is actually required.

The application concept. Click to enlarge.   Interior of the APU. Click to enlarge.

The maximum output is 3 kW, the possible efficiency is up to 40%. The system can be used as a supplier of energy not only during stationary periods but also on a permanent basis. When the truck starts driving, the fuel-cell system starts as well, supplying all the consumers of electricity. This relieves the generator, which would otherwise require approximately double the amount of fuel to provide the electrical power as the diesel fuel-cell system, Eberspächer says.

The longer the fuel-cell system runs and the more power is called off, the more it enhances the overall efficiency and cost effectiveness of the vehicle.

The basis of the Eberspächer APU is a high-temperature fuel cell that can generate electricity from the syngas resulting from diesel reforming. In the reformer, the diesel is first mixed with air; the mixture then flows through a catalytic converter. This process generates fuel gas containing hydrogen and carbon monoxide. The technology required for this process is based on the core competencies of the Eberspächer Group.

The mixture formation is based on our know-how in the area of fuel-operated pre-heaters, whereas in catalysis our exhaust technology skills are brought to bear.

—Dr. Klaus Beetz, COO Eberspächer Climate Control Systems

The electrification of commercial vehicles is an important aspect in further fuel and CO2 reduction in the transport sector, and the diesel fuel-cell APU is an important part in this future strategy, Eberspächer says.

Many energy-intensive consumers previously coupled with the drive engine—such as the cooling water- and hydraulic pump or the compressed-air system—could in the future be operated considerably more efficiently using electricity from the mobile fuel-cell system. Even the air-conditioning compressor, today coupled with the engine, plus an additional auxiliary cooling system could be replaced by a single electrical AC system for driving and stationary operation.

The output of the drive engine would then almost exclusively take care of propulsion, which would reduce consumption further. Thanks to the switch from mechanically to electrically driven components, the weight distribution in the truck could also be bettered. And, because the battery is constantly in an ideal charging state during fuel-cell operation, the batteries lifetime lasts longer and the truck cuts out more rarely.

At the present time we’ve not yet reached the end of development. But currently we’re pressing ahead with the systems development together with a well-known commercial vehicle manufacturer. Before this year is over we’ll be carrying out extensive practical testing and are planning to launch the fuel-cell APU initially on the US market at the end of 2017.

—Dr. Beetz


Ed O'Malley

3kW to provide air conditioning and cab electricity? Or cab heating, cab electricity and main engine block heating? I do not think it is nearly enough. When I was manufacturing diesel APU's we provided 25,000 BTU/hr cooling through a belt-driven compressor and it was barely enough to keep the cab comfortable when parked in 100+ degree sunlight. That took probably 6kW of power all by itself. And they do not mention the price of this APU, but I bet it is way up there. An installed diesel APU, back in 2005-2008 anyway was around $9,000.


25,000BTU/hr is an energy flow of 7.3kw.
That is one heck of a lot of cooling.
My flat uses perhaps 1kw.

I suspect that your 7.3kw is also at the point of generation, which was then transmitted not too efficiently to a not very efficient air conditioning system.

As you say, the early fuel cell systems are going to be expensive, so the their is plenty of incentive to optimise the balance of the system.

Fuel cell costs are dropping fast so and so should costs of these APU's.

Roger Pham

It probably requires only only 1 kW of power to remove 3 kW of heat, depending on the efficiency, so 7.3 kW of cooling power is well within the 3-kW power of the APU.

This is a good stop-gap solution until all of trucking will be done by H2-FC.


As I noted, I would guess that is power at the generation source before losses, so the cooling power is likely only a portion of that, which covers not running the Fuel cell at maximum output much of the time, as they don't like that.
1.5-2kw would be my guess as the normal output, which should be fine with modern efficient heat pumps and so on.


If you're using 25kBTU/hr to remove solar heat from the cabin, it means someone was a nitwit and forgot to put the sun shield up.

In all seriousness, this looks good by itself and looks like it would also play very nicely with a hybrid drivetrain.  Dumping excess power to the hybrid battery while the engine was off would allow it to stay off longer and reduce the periods of low-throttle (thus inefficient) operation.


So we have a fossil fuel reformer creating hydrogen and carbon byproducts(hydrocarbons, co, etc.)then an H2 FC generator to handle the electrical load.

Not long before the oil companies have their FC plan in it's final phase, an FCV that runs directly on fossil fuels by reforming H2 on-board to replace the ICE and generate power for EV drive line on Hybrids.

Why, nothing really changes; now you can still fill up at the pump with fossil fuel and the oil companies can go right on destroying the World.


We should have Open Fuel Standard so that we can use methanol in engines, but using it in this is the next best thing. Methanol can be made without using crude oil, in fact we can make synthetic diesel without using crude oil. If you make it out of biomass the CO2 emitted is absorbed by the plants as they grow.

Roger Pham

One thing will change: Renewable-energy H2 will be cheaper and then much cheaper than petroleum in the next few years once FCV's will create a market for it, with economy of scale and competition.


Roger, so long as RE requires support from tax credits or feed-in tariffs, neither it nor anything made from it will be cheap.



They will certainly not be cheap initially.
However there is nothing which makes them inherently expensive, as there is no high pressure fuel tank, and progress on reducing/eliminating precious metals in catalysts is rapid.

Whilst they may not be cheap, idling regulations mean that they should be commercial as production builds up and costs drop.


The need for "excess" power for a large, US-styled sleeping cab is all about pulldown. Cabin pulldown on a soaked aircraft, 98% hot day at a high (e.g., Denver) airport sizes the air flow requirement for aircraft APUs; it usually is a tougher requirement than engine starting, IIRC.

For those of you with EVs having an energy usage display, you can clearly see it. It's been a very mild summer, but I have observed 1.5kW peaks for the a/c when parked on a freshly blacked parking lot for an hour at 90degF.

Put this truck in the rest area of an I10 stop on an August afternoon, driver goes in for dinner and a shower and comes out to get ready to settle in. He will need a couple of tons of cooling to get his "residence" tolerable within 15 minutes or so.


If you use HTPEM the membranes are less expensive and the requirements for less CO are reduced. The balance of plant costs are less because the water created is steam, so you don't have to do a lot of water management keeping the membranes moist so they don't dry out and become damaged.


If I have a 50 mile commute to work and I have a 70 mile range EV but there are no recharge stations, no problem. I leave the car parked in the lot recharging with an HTPEM.


I think it will be a long while before you run your car on a diesel FCEV.
They weigh a ton!
Probably literally for anything capable of powering a car.


I should have added, the technology is fine for an APU in a truck, but nowhere near the power weight ratio needed to power a car.


Diesel to PEM fuel cells don't weigh a ton, the unit in the Volvo C30 can use diesel and it does not weight a TON.
I thought you were the scientist with the numbers and proof?


Welcome back Mr Ed O'Malley. Do you have any updates about the Motiv engine that generated so much excitement here?

And I might wonder whether the CO reformed from this type of APU would not be most useful in boosting the acceleration of the main engine. The load and driving conditions of trucks arguably vary far more than in cars. CO might also be a good complement to a natural gas fuel system (which would accommodate a dual fuel diesel/CNG system). The hydrogen would be best for the electrified power component.


I never said the commuter car would use diesel, it could use methanol. A 3k unit would charge the EV while it is parked at work for 8 hours, that was my point.

Maybe THIS is why I have not gotten through to people for eight years on here, they don't read, they don't understand and they don't care. I just hope others from Facebook and elsewhere take the time to read people's posts.


And you were the guy who never over-reacts!
That ludicrous interpretation of what I had to say is yours, as you dislike me telling people who are absolute to check their facts and stop talking nonsense.

I simply gave a top of the head assessment.
If you have better information, provide it and stop being an ass.

I have nowhere said that those who think that diesel fuel cells are 'nonsense which has to be stopped'.


The power cell that SJC id referring to in his own inimitable fashion so that aggression is always someone else, not him, as his manner of address is always perfectly angelic appears to be the Powercell S2:


The specs for the bigger units in the range appear to be within the range of providing cruising power, not just ancillary.

I can't spot how much they weigh, so if anyone has data it would be useful.


BTW, not only did you choose to grab a piece of the action in a dispute which was nothing to do with you, you have now chosen to drag it into another thread.

That is something that with the exception of Kit P I rarely do.

And it is me who is keen on causing trouble, not you?

Roger Pham

In bumper-to-bumper traffic, the idling Diesel engine is not anywhere near its peak efficiency. If a modest-size electric motor/generator can be placed between the engine and the transmission, then the APU can power the truck completely to allow the engine to stop. Braking regen recup energy for slow-speed stop-and-go traffic to reduce demand from the APU and increase efficiency.

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