Caption: Figure 12: Temporal variation of ratio of specific heats: (a) lean mixture
and (b) rich mixture.
You might also find that spark plugs are fouling easily, even with a lean mixture
set for taxiing.
Thus, the late fuel injection forms a stratified mixture in the cylinder, where fuel vapor is carried towards the spark plug location such that a slightly rich mixture exists there; with a very lean mixture
at other locations and an over lean mixture
in the cylinder .
The fuel advancing helps in the high load conditions to release low HC for 40% SFME same time the release of HC is more for both 20% SFME and 40% SFME in injection advancing and it may be due to the lean mixture
As for the rationalization for why the ACIS is called for, he explains, "As you add more exhaust gas and lean mixture
out, the mixture is more difficult to ignite, and it burns really slow.
Meanwhile, a lean mixture
is one where is some air is left after combustion is completed.
The lean mixture
also provides a more complete combustion process resulting in reduced CO and hydrocarbon levels in the exhaust.
Towards lean mixture
CO levels are approximately constant at a low level of about 0.5% or less.
Because fuel additive improves the reaction of fuel lean mixture
with surrounding oxygen, gas temperature slightly increases and, consequently, more unburned fuel vapours as airborne aerosols appear in the exhausts.
For lean-burn engines, the venturi and ECV5 are used with a wide-range [O.sub.2] sensor to maintain a constant lean mixture
. This mixture can be programmed to change with engine load as the signal requires.