Liquefied petroleum gases (LPG) and natural gas (NG) were used as a fuel for a spark ignition type (Prodit). The effect of some design and operation variables on the emitted CO emissions from a spark ignition engine was investigated. The studied parameters were compression ratio, the equivalence ratio, engine speed and spark timing variation. The emitted CO was studied at an engine higher useful compression ratio, which was for gasoline 8:1. The results were compared to the engine output when it was run at the higher useful compression ratio for LPG and NG. The study results indicate that the CO emissions maximum values lay always on the rich side equivalence ratios and its concentrations become low at lean operation. CO concentrations were lower than emitted emissions from gasoline engine. The most significant effective parameter on the CO concentrations is the equivalence ratio.

Liquefied petroleum gases (LPG) and natural gas (NG) were used as a fuel for a spark ignition type (Prodit). The effect of some design and operation variables on the emitted CO emissions from a spark ignition engine was investigated. The studied parameters were compression ratio, the equivalenc...