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Mixture preparation is a key contributor to both the combustion and emissions in automotive gasoline engines. The air-fuel ratio near the spark plug may have an effect on combustion characteristics since it is related to early flame development. Therefore, cycle resolved measurements of equivalence ratio near the spark plug is particularly important for better understanding of its contribution on combustion and emissions. This paper describes how we determined the in-cylinder equivalence ratio from the measured hydrocarbon concentration near the spark plug using a Fast Response Flame Ionization Detector (FRFID). The procedures established were then applied to a limited range of engine operating conditions, and the cycle resolved equivalence ratio near the spark plug was determined from the measured hydrocarbon concentration.

In this study, experiments have been conducted to investigate parameters that effect the catalytic reaction of methane. Parameters considered were catalysts, catalyst additives, space velocity and exhaust gas components (NO, CO, H2O, O2, CO2). Catalysts used in the experiment were Pd and Pt metal loaded on γ-Al2O3 on a cordierite monolith. Methane conversion efficiency was improved for the Pd series catalyst with additive of La and Zr. With Pd/Pt catalyst, the presence of nitric oxide and water vapor showed an inhibitory effect on methane oxidation. Methane conversion efficiency decreased rapidly over 60000 h-1 space velocity.

A 40MFLOPs DSP(Digital Signal Processing) based data acquisition and engine control system with 2-microprocessors (one for DSP, the other for host computer) has been developed for the rapid acquisition of analog data from an engine with ECU. With the use of a DSP system, it has been demonstrated that high speed data acquisition by 8 channels (0.8MHz/CH) as well as real time display and real time processing of various thermodynamic & knocking analyses are successfully performed. The engine operating conditions are to be changed through a serial communication interface, and performance of an engine can be analyzed as a function of time or crank angle. As a result, the correlations between engine performance and various engine operating conditions can be obtained with high speed and ease.

Combustion of a spark ignition engine is often idealized by a constant volume process. However, due to piston motion, constant volume combustion can not be realized in an actual engine cycle, and this leads to a loss in thermal efficiency when compared to an ideal Otto cycle. In this paper, such a loss associated with piston motion, termed as time loss, is rigorously studied for spark ignition engines of different piston motion mechanisms. It is found that the time loss of a conventional slider crank engine amounts to maximum 9 % of the total loss depending upon operating conditions. Especially, in the limit of long crankshaft, where piston motion follows a perfect sinusoid, it is shown that the time loss decreases by 2 - 5 %. To determine the dominant factors affecting the time loss, also investigated are the effects of major performance parameters such as compression ratio, combustion start and duration.