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Engine combustion behaviors were investigated when the mixture condition at the intake port was varied. This experimental study was performed for several engine variables including types of cylinder head (gas motions), spark plug loction and MBT timing. Among the variables for the mixture condition at induction were the fuel/air mixture ratio (excess air factor) and the portion of atomized liquid fuel out of total fuel in the mixture. The engine operation was analyzed by obtaining the mean effective pressure, thermal efficiency, heat release history, stability of combustion, and lean misfire limit.

The instantaneous heat transfer through the piston was measured in a motored direct injection-type diesel engine. The engine piston was equipped with a fast-response thermocouple on the surface and at a specified distance below the surface thermocouple at a number of locations. In order to record and process the measurement of temperature and cylinder pressure, a personal computer (PC)-based data acquisition system was connected to the probes, A special linkage device was designed and implemented to connect the thermocouple wires between the bottom of the connecting rod and a stationary point on the oil pan. The surface heat flux was calculated using a one-dimensional conduction model with the measured temperature boundary conditions. The in-cylinder pressure data was used to calculate the cylinder air temperature and the instantaneous film heat transfer coefficient was calculated by using those in-cylinder measurements.

Visualization of in-cylinder reaction processes and performance analysis of a direct-injection Diesel engine equipped with a high injection pressure (HIP) unit were conducted. The study was directed towards evaluation of high-power-density (HPD) engine design strategies, which utilize more intake air operating at rich overall fuel-air ratios. Two separate engine apparatus were used in this study: a Cummins 903 engine and a single-cylinder optical engine equipped with the same family engine components including the cylinder head. The engines were mated with an intensifier-type HIP fuel system fabricated at Rutgers which can deliver fuel injection pressure of over 200 MPa (30,000psi). The one-of-a-kind high-speed four-band infrared (IR) imaging system was used to obtain over fifteen hundred sets of spectral digital movies under varied engine design and operating conditions for the present analysis.