Based on a gasoline direct injection

exhaust gas turbocharged and downsized high efficient engine

comparing tests of low end torque

combustion and economic

emission performances at middle speed have been done when the conventional spark plug ignition and the pre-chamber system were assembled into the engine respectively. The effects of pre-chamber ignition and spark ignition on the engine performances differences were explored and analyzed. The results indicate that at 1500r.min-1、BMEP 2Mpa operation point

combustion constant volume efficiency is enhanced with peak fire pressure increasing

and combustion phase is advanced by 7.1°CA

resulting in brake specific fuel consumption(BSFC) improved by 24g/kWh. When the engine operates at 2000r.min-1 loads

pre-chamber can improve combustion cycle of variation(CoV) and shorten burning duration

also the combustion phase is advanced remarkably at big load

getting fuel benefit of 7g.kWh-1 with bake thermal efficiency increasing from 36.9% to 37.5%

while BSFC floats up a little bit at light load. When turning to gas emissions

NOx increases by 15% when pre-chamber system is used

and HC decreases by 36%

while CO emission keeps relatively stable

only decreasing a little bit at big load.