ETC Fault Analysis And Performance Optimization On Heavy Duty Gas Engine

Researching, development and application of heavy-duty natural gas engines are the effective measures to reduce emissions and environmental pollution. Heavy-duty gas engine is on the basis of the gm to keep most of the diesel engine parts, focus on the inlet and exhaust system, distribution agencies were redesigned and all the natural gas engines parts dedicated are associated with the electronic control unit, and gasoline engine dedicated a has certain compatibility. This paper is based on the natural gas engine initial matching BOSCH electronic throttle as the research object, throughing comprehensive testing equipment, FTA(fault tree), DOE full-scale test software and hardware technology in-depth to analysis and optimize the product structure defects.Firstly, the paper according to the natural gas engine electronic control unit control strategy and working principle of the electronic throttle, combining with the characteristics of electronic throttle bench test and vehicle working environment parameters. Choose a suitable power source and origin of device, determines the control parameters, such as valve opening to develop comprehensive testing equipment, and declare invention patent. The equipment is widely used in fault detection analysis.Second, by analyzing the fault product disassembly, clear electronic throttle failure mode. On the analysis of failure mode and its defects show that electronic throttle needle roller bearing(no shaft end seal) structure is the important reason for the product card lag problems, using the DOE test full factorial experiment model of bearing and shaft end structure, and through the electronic throttle static and transient test to validate, ball bearing and skeleton oil seal structure optimization scheme are determined, in order to complete the scheme of the electronic throttle motor matching test.Finally, through the cover board function caused by untight seal failure parts disassembly analysis, an electronic throttle plate sealing ring the compression ratio is calculated, according to the rectangular sealing ring static sealing characteristics, the optimal compression ratio is determined to25%, and the thickness of the rectangular sealing ring sizes determines from 3 mm to 4 mm, compression ratio from 14% to 25%, the new product structure and the suppression of immersion test have completed.The above test results are conform to the product performance parameters, the product in accordance with the relevant standards before release test plan and design to complete the high/low temperature storage, high temperature shock, wet and heat cycle, salt spray, vibration test, durability, resistance to chemical reagent, such as eight type testing, the new structure of electronic throttle type performance meet the requirements of product standards.New structure of the product after the completion of bench test and type test, according to the geographical environment characteristics of the vehicle road test verification, the service life of the road test shows that the new structure of the product structure of older products have obvious growth, on the basis of the original 50000 km extension nearly 1 times, failure rate fell to 0.79% from 2.78% at the beginning, a new structure of the product has been done on WT series heavy card gas engine switch, and gradually widely used in the MT series heavy card on natural gas engine.