As a direct result of this level of interest, many individuals and companies have begun to market devices and concepts for using hydrogen to run their every day vehicles. There are two main systems, with quite different technical variations.
The first, and most straightforward concept, is to simply substitute hydrogen for petrol or diesel. Hydrogen is made by electrolysis, either on-board from the alternator electrical supply or at home using mains electricity, and then burnt in the engine. The energy released drives the vehicle in the usual way. In principle this system does of course work. The problem is that the whole process is very inefficient, and the energy you get from burning the hydrogen alone cannot possibly be enough to supply the energy required to make the hydrogen in the first place.
With an on-board system, the engine is only about 40% efficient at best, and the alternator perhaps 90%, so even if you assume the electrolysis is 100% efficient you only get back about a third of the energy you put in. There is also a considerable amount of weight added to the vehicle with this system.
Another system uses the hydrogen as a supplement to the petrol or deisel (as a combustion enhancer). The concept of this system is that adding quite small amounts of hydrogen to the fuel/air mixture cause improvements to the burn, which in turn leads to better economy and reduced emissions. This system obviously weighs a fraction of the on-board system.
Many devices that produce hydrogen via on-board electrolysis feed not pure hydrogen, but a mixture of hydrogen and oxygen, to the engine. This mixture (two parts hydrogen to one part oxygen) is commonly known as Brown’s Gas. Several reputable studies have been done into the concept, and there is no doubt that adding hydrogen to a petrol / air mix in the correct ratio gives the following benefits:
- Better ignition
- Higher flame speed
- Reduced tendency to knock
- Natural de-coking effect on head and valves
- Cleaner exhaust emissions
- Increased economy
These substantial improvements in power and economy can actually be verified – Arvin Meritor claim up to 20-130%.
So, this is a great technology and we should all rush out and bolt hydrogen generators onto our cars? I didn’t say that….If the system fits your car and you have an interest in doing your part for the environment, then you can benefit financially from fitting this system to your car. The lower fuel costs alone are worth the effort but you will actually clean the inside of your engine and prolong the life of engine and catalytic convertor by the addition of hydrogen to the burn process. Add to this the benefit to your local environment and it seems like a no-brainer….but the choice is still in your hands.
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