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Forum » EV Forums » Tech Log

Air Hybrid Engine

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Written on: 18 October 2008 [22:00]
ecoadmin Administrator Topic creator registered since: 20.07.2007 Posts: 505	I discovered recently in a local newspaper an article introducing the air hybrid engine technology. Interesting stuff I thought and kept on reading... Together with Bosch, a car part supplier, and supported by the Federal Office for Energy in Switzerland, a team of scientsts is working on a prototype of such an engine. A similar if not the same type of engine is developed by the Scuderi Group. http://www.scuderigroup.com On their website it says that they also collaborate with Bosch, so it seems there is a link somewhere.... How does it work: The air hybrid engine will cost about 20% more compared to a normal petrol engine. The advantage over parallel and serial hybrid technologies using electric motors is mainly the price. Hybrids like the Toyota Prius are relatively costly. In countries like China or India such a car is too expensive for most people. Although it is expected that battery costs will come down over time, a car with hybrid technology is likely to have a higher price tag due to its complexity. But lets go back to the air hybrid technology. The stored compressed air in the pressure tank serves as energy storage. The stored air pressure can be used to directly power the piston engine. The fuel consumption is lowered by approx. 30%. In-town consumption is lowered even more to 50%. Due to its simplicity and modest cost, the engine could particularily be of interest to developing countries. A traditional petrol engine converts only 17% of the stored energy in the fuel into motion. According the scientists an efficiency of up to 35% is possible. The low efficiency is mainly caused by oversized/overpowered engines in todays cars. These engines are most of the time operated at low power settings and operate thus int a partial-load operating range. The air hybrid engine could be reduced in its size by 50% and still produce the same output as a regular engine. At low power settings the engine management system closes some of the fuel inlet valves. The pistons then work like a compressor and they recharge the pressure tank. Due to this, a higher load results for the remaining cylinders (i.e. they become more efficient). When accelerating, the compressed air is used to move the pistons directly or to provide the combustion chamber with fresh air. This is specially useful at low sppeds and rpm settings when the turbocharger is not yet outputting its optimum power. Do you think the auto makers will show an interest in this technology? I can't see a reason why they shouldn't... ecocarforum.com - Green Car Network
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Written on: 19 October 2008 [18:52]
childress Administrator registered since: 14.08.2007 Posts: 131	Well, I've never seen one in real-life, and that alone gives me a pretty high hurdle of skepticism to overcome -- I can go out and buy a child's electric car kit (or solar car kit) and see it in action, and that it is very simple. I know that when I was looking at a hydrogen-powered fuel cell bicycle (Manhattan Scientifics), one of the things (after I bought stock) that alarmed me was the high pressures the hydrogen was required to be at (300psi), and wondering about what it would do to my body in a crash (I've had 80-100psi bicycle tires/twike tires blow and been temporarily deafened)... Then there's the question of longevity of the hybrid engine, and training local repair personell to be able to fix it. Commute suck? Twike it; You'll like it! http://www.uiuc.edu/goto/twike
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Written on: 21 October 2008 [10:55]
Lensman registered since: 31.05.2008 Posts: 75	One of the reasons using compressed air to power a car is very inefficient is because when air is compressed, it heats up. This energy is lost when the compressed air cools; and furthermore, the cooling causes it to lose pressure. Then, when the compressed air is released to expand in a cylinder, the temperature drops again-- which again results in a loss of some of the energy in the compressed air. This seems to me to be a fundamental physical limitation. I don't see how one could ever get around it. Whether it's a dedicated "air car", or else it's using compressed air to power what otherwise is a gas engine, I don't see that there can be any real difference. Compressed air is a very inefficient way to power a car, and I don't think that's ever going to change. [This article was edited 1 times, at last 21.10.2008 at 10:56.]
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