Exhaust emissions from an SI engine operating on gaseous fuel mixtures containing hydrogen

The emission characteristics of a spark ignition (SI) engine operated in turn on H 2 and some of its mixtures with CH 4 and CO are examined experimentally. The role of changes in some key operating variables affecting the production of the pollutants CO, NO x and unburned hydrocarbons are examined and some guidelines for reducing the undesirable emissions are outlined. It is also shown that through determining the concentrations of CO and CO 2 in the exhaust of a hydrogen fuelled engine, the lubricating oil consumption rates can be derived. The effects of changes in equivalence ratio, compression ratio and the onset of knock on oil consumption are described.