Featured Motor Mouth: Hydrogen vehicles are finally getting their renaissance

From the article:

“Agnosticism,” at least as defined by Cummins, means the company’s new engines will run on the fuel of your choice, be it diesel, gasoline, propane, natural gas, or, of course, the topic of this discussion, hydrogen. Indeed, the American trucking giant may well have engineered the ultimate in internal-combustion modularity, Srikanth Padmanabhan, president of the company’s Engine Business division, saying last year that all of these variously-fuelled engines will be identical from the head gasket down. Only the cylinder head and fuelling apparatus need be changed so that they can run on said multiplicity of fuels. For even more specificity, the engine’s block, crankshaft, connecting rods, etc., not to mention external ancillaries such as alternators, oil pumps et al, will all be shared common parts.​

So the driver has a tool kit and changes the cylinder head on the fly?

Bob Wilson

 

Once again, Hydrogen for trucking has long been a good target for hydrogen efforts.

Even there though, electric trucks have been moving in on the short haul trucks.
I wouldn’t call this a renaissance, but a slowing of the bleeding.

I suspect that was poorly worded and meant that the cylinder head needed to be changed once. That the new cylinder head is the secret sauce that allows the engine to use any of the mentioned fuels.

 

That's not how I read it:

they have a high degree of parts commonality. Below the head gasket of each engine will have similar components and above the head gasket will have different components for different fuel types. Each engine version will operate using a different, single fuel.​

 

Having turned a wrench on four different cylinder heads, it is not a trivial task. But then there is the fuel supply and exhaust system differences ... not mentioned.

Bob Wilson

 

Article makes sense and demonstrates the wisdom of flexibility.

Years ago a company I worked for operated on razor thin profit margins but was part of a much larger company.

To cope with high energy prices, we had boilers that would burn fuel oil, propane, natural gas or diesel. The company would stock up holding tanks for a couple of the fuels based on the market prices of the energy. We would then convert the boiler systems to burn the most economical fuel. In that way the company wasn't caught with their pants down for having committed to one energy source. They could also stock up on energy sources when they were at their lowest cost.

 

Yeah, I didn't get the impression an end-user would be buying this vehicle and then swapping parts around to burn different fuels. More like the manufacturer found a way to cut down the complexity of offering versions that can burn different fuels.

 

Hydrogen Renaissance. If the renaissance is anything like the prior ½ century's level of unsuccessfulness at bringing energy costs for hydrogen reformation down .... yea .... we know where this is going. Wake me up in (another) 10 years.

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Cummins designed an engine line that can work with multiple fuels, instead designing a separate line for each fuel. So buying a hydrogen engine from Cummins should be cheaper than one from Brand X. Shared parts between the fuel types could also mean lower maintenance.

The article got, um, over exuberant in regards to conversion between fuels. Their quote, "all of these variously-fuelled engines will be identical from the head gasket down", links to Cummins' announcement which used similar instead of identical. It isn't just a head swap. Converting an in service engine isn't going to be any easier with these. Though the end result will likely operate better on the new fuel than other conversions.

Doesn't address the infrastructure issues.
The article also ignored the emissions question.

The equivalent for trucking would be investing in bi-fuel rigs. Converting internal combustion to a different fuel is more complicated than with external combustion. A company deciding to convert these engines would likely wait until it was the engine's time for a rebuild.

 

i suppose speedway will be building out nationwide hydrogen fueling stations

 

Maybe the point of the article is the ability to have power plants that are capable of using the greatest selection of fuels to become divorced from the concept of just one path to energy independence. Also to take advantage of the most plentiful or economical fuel sources.

Commercial and residential generators easily convert from propane to natural gas with a flip of the switch changing nozzle orifice size - they have combustion engines.

The conversion from diesel to fuel oil may be similar but i am not sure on combustion engines.

Combustion engines are currently able to run on gas or natural gas.

You may be outsmarting yourself.

 

He's either outsmarting himsel, or just reading what the sources actually said.

 

My EV is partially powered by nuclear, solar, hydro, and wind generators. No energy wasting manufacturing of combustible fuels.

Bob Wilson

 

You forgot to mention it is also powered by - king coal - natural gas - diesel fuel and in some instances fuel oil.

If power fails and you need a generator to tank up you will also be powered by gas.

A person with an electric vehicle is no better steward of the earth than anyone else.

I drive a PHEV but it is powered and charged by fossil fuels and unless you are really special you would also be generating human waste products from your body as well as a great deal of general waste that is polluting the earth on a daily basis.

There are many pieces to being an environmental steward .

 

This is exactly the strength of electric vehicles. Electricity is produced with wind, solar, Nat gas, gas, coal, nuclear, hydro, geothermal etc.
This does not describe hydrogen, although flexible engines are better than not.

 

I mentioned bi-fuel. GM once sold a bi-fuel car and truck that could run gasoline or CNG. I've seen portable generators that took propane or gasoline. There have even been a couple hydrogen/gasoline bi-fuel cars. What it takes to run an engine on those fuels is close enough that they don't require complicated systems to use both. The trade off is that the engine is optimized for just one fuel not both; same with flexfuel. The hydrogen models had half the output or guzzled twice the fuel, for example.

You didn't want to have the oil in the fuel lines on shut down with a fryer grease diesel, so those conversions were bi-fuel. Kerosene/diesel shouldn't be hard. A spark ignited and a compression ignited bi-fuel will get tricky. Which is what a diesel/hydrogen engine would be.

Cummins isn't making bi-fuel engines in this case. They are making an engine 'platform' that can be optimized for many fuels with modular components. Changing the fuel an engine uses after it leaves the factory will as much of a task as converting any other engine though. It might actually cost more as the Cummins change will involve more than just the fuel injection system. It will make better use of the new fuel after the rebuild though.

The scenario in the article isn't about switching fuels for short term price swings. It is switching for long term forces, like regulations. Buy a diesel bus with this engine today, and if diesel use in the city is banned 5 or 10 years later, rebuilding the engine and bus for CNG or hydrogen might be a viable option because of the engine's core design.

 

The earth is what it is but I can make choices that keep my green money in my wallet:

• "king coal" - going bankrupt because other sources are cheaper (see Blackhawk, Blackjewel, Cambrian, Cloud Peak, Piney Woods, Trinity)
• "natural gas" - cheap energy also fires my house furnace
• "diesel fuel" - expensive, used on isolated islands and remote locations
• "fuel oil" - even less practical, expensive

I have an automatic, 16 kW, emergency generator. Local electricity costs $0.12/kWh but my benchmark showed the generator burns $0.45/kWh of natural gas. The 2016 generator uses a cheap, two cylinder, air cooled engine. Regardless, you are welcome to call me a "steward of the earth" but don't expect a response.

So here are my recent charging history and costs:

• Covers an 11 day, 4,600 mile trip to Las Vegas, Los Angeles, Phoenix AZ, Sanford AZ, Vicksburg MS, and home in Huntsville AL.
  • Longest drive to Albuquerque NM, 1,300 miles in 30 hours
  • Stayed in motel with free EV charging and breakfast
  • To Las Vegas, 1,888 miles for $166 SuperCharger fees

So for the past year:

• ~13% are free charging at local shops and opportunities along routes

So this is what charging electricity costs:

• Local, Huntsville driving, ~5 mi/kWh
  • $0.12 / 5 ~= $0.024 / mi :: $2.40/100 miles
• Cross country, 75 mph interstate, 40F, ~4 mi/kWh
  • $0.35 / 4 ~= $0.0875 / mi :: $8.75/100 miles

Thanks to the magic math of partial fractions for the year:

• $0.00 * 13% (the App requires a non-zero value for Other which is free.)
• $2.40 * 46% = $1.104 / 100 miles
• $8.875 * 41% = $3.639 / 100 miles
• $4.743 per 100 miles for year

Call me a "steward of the earth" and I don't care. Call me a cheap to drive car owner and I'll vigorously agree.

Bob Wilson

 

This multi fuel design likely came from cummins participation in super truck II program and their experience with both diesel and natural gas engines.
https://www.cummins.com/news/2021/08/10/supertruck-ii-team-reaches-never-achieved-55-brake-thermal-efficiency

They have been building natural gas engines for years and there is no reason that they should not share many parts with their diesel engines. A hydrogen engine other than compression and air fuel mix ratio is the same as a natural gas engine. This hydrogen version of the engine is slated for commercialization in 2027, and since regulations in states like california and even many european nations may ban liquid fuel engines around 2040, this gives them a way to future proof. A truck owner can do an top overhaul conversion and still keep the bulk of the truck engine.

daimler's freightliner has been the most efficient in super truck II. The engine hasn't been approved for comercial yet. Freightliner also has the eCasscadia bev semi truck. They are buying cummins fuel cells to modify this as hydrogen truck. A hydrogen ice still produces NOx which requires EGR and further pollution control, using a fuel cell eliminates these costs but reliability, up front costs, and maintenence currently are more expensive. Given a 100 kwh battery am aerodynamic semi should be able to get by with just 2 or 3 small fuel cells like are used in the mirai. The big question is regulation and subsidies for hydrogen fueling and hydrogen fuel. Companies are getting prepared for governments to impose hydrogen.

Oh and you can build a flex fuel diesel and spark ignighted higher efficient engine. Wasailia does this for ship engines, but these are low speed engines so differences in valve timing aren't important and the spark plugs don't seem to hurt efficiency of these huge engines when burning diesel. It just is they are extremely expensive. The cummins diesel/gasoline/natural gas/hydrogen through a top overhaul makes a lot of sense if you want to sell a diesel truck today, but allow conversion if regulators decide its important.

Super truck III program has started. I'm expecting these will be phevs which will allow for less engine maintenance. I expect Freightliner will use some of the e-turbo technology other dymler company mercedes helped develop for f1. Its super truck II system already has a 48V system and the electric supercharging, and using the turbo as a generator when less power is needed from the engine, should allow it to operate most of the time at a low rpm efficient miller cycle, with less pollution before emissions control than variable turbos.

 

How bad can NOx get with a vehicle engine? Saw a statement than a natural gas turbine using hydrogen blends could have the NOx levels climb 600%. A three way catalytic converter won't help has it need CO and hydrocarbon inputs to work.

 

If your exhaust system is built to include diesel then it will be a 2 way cat for hydro carbons and carbon monoxide, and an SCR unit to remove the NOx. Even lean burn hydrogen will produce a lot less NOx than diesel. If it was hydrogen only you don't need the 2 way cat, just the SCR unit.