Motorcycle engines are required to have high output levels but low exhaust gas emission levels. Measuring the combustion condition proves useful for understanding the engine's operating condition. We developed a compact, high-performance combustion analyzer for measuring the combustion condition of motorcycle engines. This newly developed combustion analyzer is capable of analyzing the indicated mean effective pressure at each engine cycle at the engine speeds exceeding 10,000 rpm required of a high-performance motorcycle engine. Its compact size makes it easily applicable for onboard use, allowing measurement in any operating condition, including circuit travel, which has never been possible with conventional combustion analyzers.
We used this new combustion analyzer to measure combustion condition not only on a chassis dynamo but also during circuit travel, when the motorcycle and engine are subjected to much harsher operating conditions. In comparison with such conventional measurement data as engine speeds, throttle position, and air-to-fuel ratio, the information we obtained allowed us to grasp the combustion condition during transitional operation for each engine cycle. Such instantaneous and detailed information that has been impossible to obtain with conventional measuring methods proved extremely effective for improving the engine combustion condition, including the transitional characteristics.
This paper describes examples of its practical application.