by Jim Kerr
Fuel cells are the ultimate choice for hydrogen-powered vehicles but they still need several years of development. The Saskatchewan Research Council’s (SRC) solution: take a modern vehicle on the roads today and convert it so it will use hydrogen to supplement the existing fuel source. Sheldon Hill, SRC’s Project Leader for the “First Generation Hydrogen Vehicles” led me through the development stages of their latest project vehicle, a 2001 Chevrolet pickup equipped with a Duramax diesel engine.
Hill and the SRC team have several years experience working with alternate energy sources and in the past have focused on propane and natural gas. With the changes in the world economy and the increasing volatility of supply of non-renewable fuel resources, the SRC team decided they needed to look at a hydrogen future.
ECCE Energy Corporation, commissioned them to investigate practical hydrogen applications. One of ECCE Energy Corporation’s objectives is to supply hydrogen fuel at retail fuelling stations but in order to accomplish this, there must be vehicles on the road that can use hydrogen as a fuel. It’s the age-old question. Which comes first: the chicken or the egg? In this case the two must appear at the same time. The development of hydrogen-powered vehicles became part of their goal to provide transportation fuels for the future.
Natural Resources Canada (NRCan) joined the project to aid the research funding. In a time when federal funding is under intense scrutiny, the NRCan funds appear to have been well spent. In only 9 months of a 20-month project, the SRC has been able to put a diesel/hydrogen-fuelled truck on the road and are working on a gasoline/hydrogen vehicle as well. While the project still has much to complete, the results so far are impressive.
How does the truck work? Much of the actual mechanical, electronics and programming are still proprietary information with several potential patents in progress, but Hill was able to share enough information to provide a concept of the operation.
Start with the fuel tank. Cylindrical tanks mounted in the box specifically designed for hydrogen store the fuel at 5000 psi. From there, the hydrogen is regulated and flows to four electronic injectors that spray the fuel into the intake manifold. The hydrogen flows past the intake valve into the engine’s cylinders where it is ignited by the injection of diesel fuel.
The truck runs on both diesel and hydrogen fuel at the same time. By introducing supplemental hydrogen into the cylinder, the amount of diesel injected can be significantly cut back. The diesel injection is used mainly to control the timing of ignition. It sounds very simple but the control system is the heart of the operation. While Hill states that the truck control strategy still needs to be optimized, I found it worked very well even now!
Starting the truck on diesel fuel, you hear the typical combustion knock rattling sound of a diesel engine. After it had warmed up a little, the hydrogen switched on. With the hydrogen, the engine began to run a little quieter and smoother. The GM Duramax already is a quiet and smooth running diesel engine but the hydrogen fuel did make a difference.
On the road, we were able to switch the hydrogen fuel off and on to observe differences in operation. The truck had as much if not more power and the accelerator pedal inputs were more responsive when running a combination of diesel and hydrogen. At highway speeds, the engine also ran quieter. The electronic controls provide flexibility to vary fuel delivery, so horsepower and torque output can remain the same. There seem to be no operational drawbacks to using hydrogen as a supplemental fuel other than the space taken by the storage tanks, and even this could be optimized for production vehicles.
Cost of operation is always important. Hill says it is too early to talk of miles per gallon or cost of fuel, but predicts that hydrogen fuel would be cost competitive with other fuels and be a reliable and renewable source of energy.
Hydrogen safety is a key part of the research project. Hydrogen is a non-odourized gas so gas sensors located both in the storage tank area and under the hood and redundant controls are part of the safety design. In reality, hydrogen is much safer than gasoline. If hydrogen is accidentally released, it dissipates in the air almost immediately, compared to gasoline vapours that remain for some time.
So why use hydrogen? Low exhaust emissions are a desirable benefit but perhaps even more important is hydrogen can be a renewable fuel resource. Electrolysis to produce hydrogen has environmental benefits – we can use wind or solar power and there is a lot of interest in that because of environmental synergies, but the most economical method of producing hydrogen is to reformulate natural gas. The next best way is to reformulate methanol and ethanol. The future could shift from a petroleum-based economy to an agriculture-based economy where methanol and ethanol are king instead of oil.
Short haul commercial diesel powered trucks are seen as a first real commercial market for this technology although it could easily expand to the passenger vehicle market. Will your next vehicle use hydrogen fuel? Hill sees converting 20 to 50 vehicles as a reasonable target in the first year. With substantial investment money, this could potentially expand to 5000 vehicles in the next two years. Maybe it is time to get ethanol production on stream now!