The Failure Analysis And Design Improvement Of LNG Engine Starter Gear

The driving gear as the main components of the transmission system, used to transmit the disc engine flywheel ring gear output torque, high transmission efficiency, compact structure, stable transmission characteristics. In natural gas engine air cylinder mixed gas compression, the mixture in the cylinder gas engine work caused by tooth ring feedback to the alternating resistance torque starter is different; at the same time, the ignition of diesel engine is a compression ignition diesel ignition and burning low, while the ignition gas machine for electronic lighting and natural gas burning high, thus the changes the cylinder compression times during starting of the engine at different times, compressed gas machine is about 4 times of compression times of diesel engine. The reasons of natural gas and diesel engines for driving gear strength requirements are quite different, the driving gear in the gas environment to withstand frequent alternating torque and violent shocks are more likely to cause the driving gear fatigue fracture.Analysis of working process of software on the starter curves were compared using the Pico Log test, find out the diesel engine and gas engine during starting current, the starting torque and drag the average drag, the average compression number of difference, combined with the failure mode analysis, find the reason and the solution plan; at the same time,because of the influence of strong alternating gas machine load, find out from the design parameter optimization of the driving gear promoting best parameter combination drive gear strength.Conclusion DOE test system design is based on the analysis of main fault factors,caused by the driving gear driving gear strength, failure of the engine cylinder number, the average drag when starting current, and the starting resistance torque, the braking torque is caused by minor failure factor of gear. Engine cylinder compression times is the inherent characteristics of gas engine, so as to enhance the average driving current driving gear strength and improve the start has been the main breakthrough will drive gear failure point.Final material research program driving gear design parameters for changing the driving gearfor 20 Cr Mn Ti, reducing gear has 10 teeth, increase the root fillet of R1.5, the modification coefficient is set to 0.8, as the final programme for the improvement of gear in order to improve the average drag; current when starting, the planetary gear transmission system of the Department of motor the ratio changed from 5 to 4.