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The technique of using cylinder pressure data for diagnosing the combustion process in a reciprocating internal combustion engine has been used for some time. Much of the early work, however, was qualitative comparisons of the heat release rate diagrams. Only recently have efforts been made to reduce the heat release diagrams to functional or numerical representations which could be used to make fuel-to-fuel and engine-to-engine comparisons. This paper describes work in which cylinder pressure measurements were taken from an operating diesel engine using a high-speed data acquisition system. Combustion chamber pressure measurements were made at approximately 1.0- degree increments over several engine cycles using a real-time data acquisition system. The pressure data were used to calculate apparent heat release and indicated horsepower. Both radiative and convective heat transfer computations were included in the calculational procedures.

The purpose of this work was to develop a series of octane reference fuels for road testing methanol fueled vehicles. Preliminary attempts to measure the research octane number of neat methanol by the standard ASTM test procedure produced anomalous results. This led to a more basic method of measuring the octane number based on the incipient knock compression ratio. The incipient knock method gave research and motor octane numbers of 112 and 88, respectively, for neat methanol. Research octane numbers of several methanol reference fuel blends prepared by adding octane enhancers and depressors were determined. The effects of spark timing and air/fuel mixture temperature on the incipient knock compression ratio of neat methanol were also examined.