Originally Posted by
megan
I've read that all the do dad electronics on todays average car has more to do with meeting pollution requirements than improving economy
Not actually true, I'm afraid. Most modern automotive engines use "stratified charge" combustion to get the efficiency - a concept which generates layers of lean and rich mixture inside the combustion chamber to get the lower consumption of the lean-burn with the higher speed of combustion in the rich mixture. It requires very precise metering of injection settings (duration and timing), ignition timing and (in turbocharged engines) cylinder pressures. Parameters like cylinder and intake air temperatures are part of the equation along with throttle demand and demand rate, rpm etc. This is even more true for diesels than for petrol engines (other than the ignition timing, obvs!). Without the "electronic do dads" the fuel consumption would be typically 20-40% higher, especially on short trips. The reduced fuel consumption improves most of the emissions but the more aggressive combustion (higher pressures and temps) does tend to increase the production of nitrates - these are addressed by other means.
PDR