Research On Monitoring And Diagnosing Technology For New Medium-speed Diesel Engine

As the most common power mechanical equipment, diesel engine are widely used for ships, automobiles, power generations, railway tractions, mechanical equipments etc, due to its high heat efficiency, high power per quantity and easy to start. With improve continouly in the diesel engine performance and degree of automation, to ensure their running security is the key to guarantee the safety of equipments. Monitoring and diagnosing technology for the diesel engine can promptly discover the potential failure information, and take necessary measure to avoid the serious accident. in this paper, base on thermal parameters, instantaneous angular speed, torsional vibration and indicator diagram monitoring and diagnosing method on the medium-speed diesel engine are studied, the main research contents of this paper are the following:(1) The research of the monitoring method of diesel engine thermal parameters. MAN B&W 8L21/31 medium-speed diesel engine with its own set of conventional thermal parameters (box next to the machine) monitoring system,In the system design, (box next to the machine) real-time monitoring system transmits directly data to the computer by MODBUS protocol, which realized the real-time monitoring of the conventional thermal parameters. The test results showed that the use of MODBUS protocol on the monitoring of the conventional thermal parameters with well real-time, debugging capability, a lot of data transmission capacity and easy-to-use features etc.(2) The research of diesel engine instantaneous angular speed and torsional vibration monitoring methods. Instantaneous speed measure methods include software method and high-frequency clock counting method, this paper monitor and analysis instantaneous angular speed by high-frequency clock counting method, and the instantaneous angular speed measure error analysis results show that monitoring the counting of instantaneous angular speed by high-frequency clock own small error, high accuracy and convenience of calculation and so on. The fluctuations of the speed can measure each gear torsion angle, and calculate vibration of the shaft angle by integration.(3) The development of the new medium-speed diesel engine monitoring and diagnosis system. The system includes data collection, thermal parameters, instantaneous angular speed, the torsional vibration measurement, indicator diagram and database sub-module, which realized monitor, analysis and process all the major parameters of the diesel engine, and verified system through tests of the system on the MAN B & W 8L21/31 medium-speed diesel engine, test results show that the accuracy of the system to meet the actual analysis.(4) Diesel engine fault diagnosis technology research. Measure and analysis the thermal parameters, Instantaneous angular speed, torsional vibration and indicator diagram through the fault simulation tests on the MAN B & W 8L21/31 medium-speed diesel engine, and diagnosis faults of diesel engine by the instantaneous speed, torsional vibration and indicator diagram of the three fault diagnostic method.