(1.Key Laboratory for Power Machinery and Engineering of Ministry of Education,Shanghai Jiao Tong University，Shanghai200240,China;2.Shanghai Marine Diesel Engine Research Institute，Shanghai201108,China)
Under the control of the embedded industrial computer, NI data acquisition card and LabVIEW software were used to realize the acquisition and processing of output signals of nonresonant piezoelectric knock sensor and photoelectric tachometric transducer, and hence the online detection of gasoline knock based on the body vibration detection was realized. The software design of detection system was completed and the knock detection based on LabVIEW was realized through the signal acquisition module, processing module, knock determination module and data storage module. The knock test of a 3cylinder gasoline engine was conducted. By analyzing the vibration signal, the characteristic frequency range and knock threshold were determined and the influencing factors of threshold were further studied. Finally, the online detection of engine knock was conducted. The test results show that the detection system can identify engine knock effectively.
