Re:Gasoline direct injection, etc., makes electric cars irre...
by gravitycop on Friday January 30, 2009 @01:02PM
(#458406)
>> 3. Modern diesel engines produce way less smog and noise than the average US car or pickup engine.
> Modern diesel engines to not produce less smog than a gasoline engine, they produce more.
I think bdfh42 was referring to the existing fleet (including old vehicles) of registered gasoline-powered vehicles. An important point, though, is that newer vehicles tend to be driven more. To wit: the average new passenger vehicle is driven ~15,000 miles per year, whereas the average registered passenger vehicle in general (new+used) is only driven ~12,000 miles per year. The more a vehicle is driven, the more pollution it emits, so it is important for new vehicles to be cleaner than old vehicles.
Diesel fuel has a higher energy content because it is heavier, this requires a higher ignition temp/pressure that leads to the NOx problems others have mentioned.
Modern diesel engines to not produce less smog than a gasoline engine, they produce more. Diesel engines have two problems that gasoline engines lack: they produce more NOx (due to previously mentioned higher combustion temps) and they produce more soot particulates. There are technologies like particulate filters, exhaust catalysts, and exhaust gas recirculation that can partially solve some of these problems, but they are neither cheap nor widespread at the moment.
You are correct about Bosch introducing GDI to autos though.