With the global promotion of carbon neutrality policies, internal combustion
engine (ICE) of traditional fossil fuel is gradually transitioning to carbon
neutral fuel ICE, and hybrid dedicated engines are gradually replacing
traditional internal combustion engines in the passenger car market. Ultra-lean
combustion supported by active pre-chamber is one of the key technologies for
achieving high thermal efficient over 45% BTE. However, there are still issues
like cold start and PN emissions caused by impingement of liquid fuel injection
in pre-chamber, and there is still room for improvement in thermal efficiency by
less energy of pilot ignition fuel. Gaseous fuel such as hydrogen or methane
have no wetting issues, and can be more easily controlled in terms of the
injection amount in pre-chamber, thereby using a less amount of gaseous fuel as
the pilot ignition fuel could be a solution. Due to the above situation, this
article conducted experiments on a lean burn gasoline engine by injecting
hydrogen or methane instead of gasoline into the pre-chamber to ignite the
gasoline in the main chamber, and investigate its performance, combustion and
emissions. The results show that, there is a best value for both the equivalent
calorific value substitution ratio of hydrogen or methane injection in
pre-chamber and global lambda, which results in lowest fuel consumption. Due to
the fact that hydrogen has a higher activity and none carbon molecule while
methane has a lower activity and property of easily generating soot precursors
through C1 radicals, the performance of hydrogen and methane injection in the
pre-chamber is significantly different: Compared to gasoline injection in
pre-chamber, hydrogen injection in pre-chamber can reduce ISFC and significantly
decrease PN. Methane injection in pre-chamber increases ISFC and PN, the more
retarded the SOI is, the higher the PN results. Hydrogen injection in
pre-chamber can breaking through the limitation of ignition angle being too
forward of traditional pre-chamber in cold start. This article provides data and
solutions for the transition from fossil fuels to carbon neutral fuel step by
step.