Aaron Brzozowski 
When it comes to vehicles that tow and haul, eliminating tailpipe emissions is a bit of a tricky thing because battery packs are, at the end of the day, rather large and heavy. The size and weight penalties are a reality for battery-electric passenger vehicles too, of course, but they’re especially important for commercial vehicles, where they directly affect the maximum rated payload. The solution, according to one Belgian-owned automotive supply business Punch Group, could be hydrogen-powered Duramax diesel engines.
Automotive News Europe recently spoke to Belgian engineer Guido Dumarey, founder and CEO of Punch Group, which owns a variety of automotive supply facilities across Europe. One of those facilities – a powertrain engineering complex in Turin, Italy that Punch bought from General Motors after its retreat from the European market – is working to convert the mighty General Motors 6.6L Duramax diesel engine, found in vehicles like the Chevrolet Silverado HD and GMC Sierra HD, into a clean, hydrogen-burning powerplant.
That Duramax diesel-based hydrogen engine will serve as the range-topper to a family of hydrogen powerplants that will also include a 2.0L four-cylinder and a 3.0L V6. Power output for the engine family is expected to range from about 110 to 540 horsepower.
The Technical Challenges of Hydrogen
Granted, Dumarey admits that there are plenty of technical hurdles to overcome. For instance, he says, “hydrogen burns seven times faster than diesel, so you need to decrease the temperature in the combustion chamber” for proper combustion. “Water injection is a proven technology to do this, but a negative side effect is that this creates corrosion.”
And then there’s the matter of lubrication, which is “another potential issue for an engine that tends to be very dry,” Dumarey says. “Spray lubrication is the only solution.”
The rest of the GM Duramax diesel engine needs relatively little to effectively run off of hydrogen, according to Dumarey. This includes some minor changes to the cylinder head, and of course, a reworking of the injection and control systems.
As for why Punch Group is working on converting diesel engines instead of gasoline ones to run hydrogen, there are two main reasons: accessibility – because Punch already holds the right to sell the 6.6L Duramax diesel everywhere except the US – and durability. “Modern diesels are designed to last for 350,000 km,” Dumarey explains, “while gasoline engines [are] designed to last for about 250,000 km.” And Dumarey predicts that as more and more countries cut transportation emissions by limiting or banning the sale of new internal combustion vehicles, more diesel plants around Europe will inevitably pop up for sale.
So, will we ever see a hydrogen-fueled Punch Duramax diesel engine in the North American-market Chevrolet Silverado HD or GMC Sierra HD? It’s a possibility; Punch Group doesn’t have the rights to the diesel 6.6L Duramax in the US, but it does have the US rights for its hydrogen-powered version, and the presumably low take-rate might mean that it wouldn’t make sense for GM to develop and manufacture its own, different hydrogen-fueled Duramax V8. But don’t hold your breath for any of Punch’s hydrogen engines to land in any light passenger vehicles any time soon. Dumarey doesn’t believe there’s a compelling case as a light vehicle emissions solution because of the hydrogen fuel tank. While light in weight, is large enough that packaging becomes a challenge. Which is why we’ve so far seen a focus on hydrogen fuel cell vehicles in large commercial trucks.
“While the weight of the tank is a fraction of a battery pack – about 50 kg versus several hundred kilograms for the batteries – the tank requires a space of approximately 100 liters,” Dumarey says. “This is a significant packaging challenge if you want to house the tank in the trunk of a sedan. It’s even more problematic with hatchbacks.”
