Technical Paper
The Effects of Fuel Atomization, Vaporization, and Mixing on the Cold-Start UHC Emissions of a Contemporary S.I. Engine with Intake-Manifold Injection
1995-10-01
952482
Engine-out, cold-start (from 20°C) UHC emissions from a contemporary 2.0 4-cylinder engine with swirl control were measured with FID and FT-IR. The steady-state, end of test operation was 1500 rpm, 2.6 bar BMEP (25% load) and stoichiometric mixture. Four fuel systems were employed pintle-type port-injected gasoline, air-forced port-injected gasoline, port-injected propane, and premixed propane. These fuel systems were chosen to separate effects of fuel atomization, vaporization, and fuel-air mixing. Each system was optimized with respect to injector targeting, injection timing, mixture enrichment, and spark advance. Open-valve injection timing increased UHC emissions more with the pintle-type injector than with the air-forced, system. UHC emissions with propane injection were minimized with open valve injection.
