Analysis And Detection Of Knock Signal For Electronically Controlled Gasoline Engine

The knock detection system makes spark advance angle approach critical knock, avoids strong knock in gasoline engine, and improves the power performance and fuel economy performance. In this paper, knock detection is studied on CAC480 electronically controlled gasoline engine. Knock detection method is presented. This paper includes two parts, the first part introduces test result and data analysis of knock detection based on engine test bench, the second part introduces software and hardware design and development of knock detection system. In chapter 1, the reason why knock occur in gasoline engine is explained, some damages caused by knock are listed, and the trend of knock detection in the world is introduced in brief. In chapter 2,the signal character of knock, detection method and detection threshold are introduced, and the conception of characteristic frequency of knock is discussed. The data acquisition system used during the test process is also introduced. In chapter 3,the methods and steps of knock detection are introduced. Some charts and tested data are presented. The test data are analyzed and some important conclusions are obtained. Characteristic frequency and knock detection threshold are discussed In chapter 4,the hardware development of the knock detection system is introduced in detail. In chapter 5, the software development of the knock detection system and monitoring system are introduced in detail.