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An experimental study was performed to investigate the effects of various intake charge motion control valves (CMCVs) on mixture preparation, combustion, and hydrocarbon (HC) emissions during the cold start-up process of a port fuel injected spark ignition (SI) engine. Different charge motions were produced by three differently shaped plates in the CMCV device, each of which blocked off 75% of the engine's intake ports. Time-resolved HC, CO and CO2 concentrations were measured at the exhaust port exit in order to achieve cycle-by-cycle engine-out HC mass and in-cylinder air/fuel ratio. Combustion characteristics were examined through a thermodynamic burn rate analysis. Cold-fluid steady state experiments were carried out with the CMCV open and closed. Enhanced charge motion with the CMCV closed was found to shorten the combustion duration, which caused the location of 50% mass fraction burned (MFB) to occur up to 5° CA earlier for the same spark timing.

High levels of hydrocarbon emissions during light load operation keep the direct injection stratified charge engine from commercial application. Previous analytical work has identified several possible hydrocarbon emissions mechanisms which can result from poor in-cylinder fuel distribution. Poor fuel distribution can be caused by erratic fuel injection. Experiments conducted on a single cylinder DISC engine show a dramatic increase in the cycle to cycle variation in injection characteristics as engine load decreases. This is accompanied by an increase in cycle to cycle variation in combustion behavior suggesting that degradation in combustion results from the degradation in the quality of the injection event. Examination of combustion and injection characteristics on a cycle by cycle basis shows that, at light load, IMEP and heat release do not correlate with the amount of fuel injected into the cylinder.

In analyzing the processes inside the cylinder of an internal combustion engine, the principal diagnostic at the experimenter's disposal is a measured time history of the cylinder pressure. This paper develops, tests, and applies a heat release analysis procedure that maintains simplicity while including the effects of heat transfer, crevice flows and fuel injection. The heat release model uses a one zone description of the cylinder contents with thermodynamic properties represented by a linear approximation for γ(T). Applications of the analysis to a single-cylinder spark-ignition engine, a special square cross-section visualization spark-ignition engine, and a direct-injection stratified charge engine are presented.

Liquid fuel flow into the cylinder an important source of hydrocarbon (HC) emissions of an SI engine. This is an especially important HC source during engine warm up. This paper examines the phenomena that determine the inflow of liquid fuel through the intake valve during a simulated start-up procedure. A Phase Doppler Particle Analyzer (PDPA) was used to measure the size and velocity of liquid fuel droplets in the vicinity of the intake valve in a firing transparent flow-visualization engine. These characteristics were measured as a function of engine running time and crank angle position during four stroke cycle. Droplet characteristics were measured at 7 angular positions in 5 planes around the circumference of the intake valve for both open and closed-valve injection. Additionally the cone shaped geometry of the entering liquid fuel spray was visualized using a Planar Laser Induced Fluorescence (PLIF) setup on the same engine.

A prior study (Chon and Heywood, [1]) examined how the design and performance of spark-ignition engines evolved in the United States during the 1980s and 1990s. This paper carries out a similar analysis of trends in basic engine design and performance characteristics over the past decade. Available databases on engine specifications in the U.S., Europe, and Japan were used as the sources of information. Parameters analyzed were maximum torque, power, and speed; number of cylinders and engine configuration, cylinder displacement, bore, stroke, compression ratio; valvetrain configuration, number of valves and their control; port or direct fuel injection; naturally-aspirated or turbocharged engine concepts; spark-ignition and diesel engines. Design features are correlated with these engine’s performance parameters, normalized by engine and cylinder displacement.