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Two features to facilitate chemical reactions at low temperature, non-thermal plasma and the weak dependency of photocatalyst on temperature, have been exploited by many researchers to effectively decompose hydrocarbon emissions emitted until the light-off of a three-way catalyst in spark ignition engines. To develop a realizable emissions reduction reactor, as part of such effort, this study investigates for the three model gases, propylene, n-butane and acetylene: 1) the conversion efficiency of the emissions reduction reactor, which utilizes the effect of dissociation, ionization-by-collision of the non-thermal plasma and the photocatalytic effect of TiO2, and 2) the concentrations of the products such as acetaldehyde, acetic acid, polymerized hydrocarbons and NO2. The operating parameters to obtain the plasma energy density ranging from 7.8 to 908 J/L were varied.

Knock control algorithms were developed for a spark-ignition engine. Spark timing was controlled using cylinder block vibration signal. The vibration signal of a 1.5 L four cylinder spark-ignition engine was measured using an accelerometer which was attached to the cylinder block. The maximum amplitude of the bandpass-filtered accelerometer signals was used as the knock intensity. Three different spark-ignition engine knock control algorithms were tested experimentally. Two algorithms were conventional algorithms in which knock threshold values were predetermined for each engine condition. Spark timing was retarded and advanced depending on the knock intensity in one algorithm and the knock occurrence interval in the other algorithm. The third algorithm was a new algorithm in which knock threshold values were automatically corrected by monitoring knock condition.