Cycle-to-Cycle Variation Study of an SI Engine Fired by Spark Plug and a Non Conventional Device

This paper reports on an experimental investigation of an SI single cylinder engine cycle-to-cycle variations. Two different ignition devices are studied: a spark plug and a non conventional ignition device, PJC (Pulsed Jet Combustion).

In-cylinder pressure is analyzed via a complete heat release rate computation.

A significant decrease in IMEP cycle-to-cycle variations can be achieved only when the initial burning rate is enhanced with PJC device for example. The cycle-to-cycle combustion variations (CA01, PMax, IMEP) are not improved in the same proportions.

The PJC is a firing device which meets the objective of repeatable ultra-lean mixture ignition and development of combustion, but slightly lowers the global efficiency due to the increase of heat losses for high load running points.