LyrArc Article Gist
A technology that has been known for years but with problems to solve before it can go on the road is being developed by automakers. It will increase fel economy by about 15% and reduce emissions of oxides of nitrogen a key smog component. GM is working on getting HCCI which stands for Homogenous-charge Compression- Ignition to work in a gasoline engine. For it to work the combustion process in such an engine has to meet certain conditions, the mixture of air an fuel has to be homogenous and be at certain temperatures. Once this is achieved combustion occurs without a spark. The trick is to get the temperature and gas mixture to just the right homogenous levels so that it sparks and burns efficiently, which at this time is being achieved by computer controls keeping the engine rpm within a certain optimal range of 1000-3000 rpm which covers typical driving. Problems that remain to be tackled are the faint rattling type noise when the engine shifts to spark ignition when its outside this range of rpm, and the emissions reduction at low loads, and handling a range of fuels. GM has made progress upto the advanced engineering and road test phase for the Saturn Aura. German automakers Mercedes and VW are perfecting there own versions of HCCI and Honda is developing its version and its a top priority for these automakers.