The influence of the number of spark plugs

piston movement and compression ratio on the indicated work and detonation tendency of a rapid compression and expansion machine was studied through experiment and simulation. The results reveal that multiple spark plugs ignition can shorten the combustion duration and improve the indicated work

but the knock tendency increases obviously. The knock tendency can be reduced by increasing piston velocity to shorten the residence time of piston around top dead center

but the indicated work decreases at the same condition. The combination of the multiple spark plugs ignition with increased piston velocity and high compression ratio as high as 17.5 can improve the indicated work and suppress the knock

optimizing the spark ignition combustion process.