Simultaneous in-cylinder and exhaust cycle resolved non-dispersive infrared and flame ionization detector experimental sampling results during cranking and startup in a port fuel injection co-operation fuel research engine

Abstract

Optimization of in-cylinder air—fuel mixture preparation in port fuel injected engines during all phases of operation is critical for maximizing engine performance while minimizing harmful emissions. In this study, a co-operative fuels research (CFR) gasoline engine is used to evaluate torque and measure in-cylinder and exhaust CO, CO2, and unburned hydrocarbons under various fuelling and spark conditions during cranking and startup phases. Fast flame ionization detectors and non-dispersive infrared fast CO and CO2 detectors are used as the principal diagnostics. Measured component trends are shown with detailed explanations. CFR engine exhaust unburned hydrocarbon levels are shown to be 3 to 7 times higher for startup than for steady state operation depending on spark timing and fuelling. Torque is found to be relatively insensitive to fuelling within 5 per cent of stoichiometric. Additionally, in-cylinder and exhaust CO levels are strong functions of startup enrichment. Exhaust CO, much easier to measure than in-cylinder CO, could be used to meter fuel more tightly during startup in order to reduce undesirable emissions. Exhaust CO levels can be at or below stabilized engine steady state levels depending on fuelling levels. Exhaust CO2 measurements are found to be not reliable indicators of in-cylinder conditions.