|
The trouble with lean burn in North America is NOx emissions. All current North American gasoline vehicles AFAIK, run at stoichiometry (actually, the mixture 'dithers' in a narrow band either side), which permits the catalytic converter to both oxidize CO and unburned hydrocarbons and reduce NOx. Running more than a few percent lean lean makes this impossible with conventional technology (although some strategies adopted to bring '08 diesels up to US/Canadian standards may be applicable) The same Direct Injection gasoline engines which use lean burn in Europe are calibrated to run at stoichiometry in NA.
|