cleaner air package
To understand the effect of fuel ratios on combustion products, I find it helpful to look at a graphic like the one posted here: Heat riser affect wideband? - Page 2 - racingfuelsystems.myfunforum.org
You can see that leaner mixes at idle reduce CO and HC but increase NOx.
This is just 60s stuff. Later changes to try to address everything include the higher idle speeds (requiring the idle stop solenoids) to deal with relatively retarded initial timing, temperature controlled air intakes, EGR, cats, etc.
To understand the effect of fuel ratios on combustion products, I find it helpful to look at a graphic like the one posted here: Heat riser affect wideband? - Page 2 - racingfuelsystems.myfunforum.org
You can see that leaner mixes at idle reduce CO and HC but increase NOx.
This is just 60s stuff. Later changes to try to address everything include the higher idle speeds (requiring the idle stop solenoids) to deal with relatively retarded initial timing, temperature controlled air intakes, EGR, cats, etc.
