자동차 배기가스의 증가요인인 실화발생을 감지하고 실화가 발생하는 기통까지 판별하기 위하여 종래에는 크랭크각속도를 측정하는 방법을 이용하였으나 이 방법은 고속의 회전시 감지가 어려운 문제를 가지고 있다. 이러한 문제를 해결하기 위해서 본 논문은 이산 월쉬-푸리에(Walsh Discrete Fourier Transform; WDFT)를 이용하여 고속의 엔진회전수에서도 실화발생여부를 판단 가능하게 하였고, 월쉬함수의 Moving window방식을 이용하여 다기통 실화발생에 대한 기통판별까지 가능하게 하였다. 이상의 내용을 시스템으로 구현하여 무부하 Idle상태와 운전상태(Drive)에서 시험한 결과도 실화발생여부를 감지하는데 기존의 방법보다 더 효과적임을 알 수 있었다.
The primary cause of air pollution by vehicles is imperfect combustion of fuel. One of the most usual causes of this imperfect combustion is the misfire in IC engins. The U.S. EPA(Environment Protection Agency) and the CARB(California air Resources Board) have imposed regulations for the detection of misfiring in automotive engines. The OBD-II regulations require that misfire should be monitored by the engine diagnostic system, and that the goal of OBD-II is to alert the driver to the presence of a malfunction of the emission control system. Several solutions to the misfire detection problem have been proposed for the detection of misfires. However, the performance of these methods in the presence of misfire is not altogether clear. This paper presents a precise method and system for internal combustion engine misfire. Present invention based upon measurements of engine roughness as derived from crankshaft angular velocity measurements with special signal processing method. Crankshaft angular velocity signals are processed by WDPT, so that the more reliable misfire detection than the time domain analysis. Experimental work confirms that it is possible to apply the WDFT for the detection of misfires in no-load idle and road testing.
