Study On The Key Technology Of LJ276M Electronic Gasoline Engine For ATV

With the concern of energy source depletion and environment pollution due to the multiplication of vehicles in the world, increasingly strict emission laws have been issuing in all the countries of the world. Electronic technology is a promising way for gasoline engine to achieve strict emissions laws. But up to now the fast and accurate prediction of electronic control parameters and issues related with the improvement of combustion pressure by electronic control such as the reliability of components and the noise suppressing of the engine are still remained optimizations.Now in China, almost all the ATVs (All Terrain Vehicle, ATV) are equipped with the carburetor that are hard to meet the requirement of the strict emissions laws for ATV. In this paper several key technologies for LJ276M electronic gasoline engine applied in ATV including design and optimization of air inlet system, calibration and optimization of electronic control parameters, FEM (Finite Element Method) analysis and optimization of connecting-rod and simulation and improvement of exhaust muffler were studied. Some interesting results are concluding as following:(1) Based on the artificial neural network theory, a novel model was proposed to forecast the electronic control parameters when engine runs at steady-state by using highly nonlinear mapping ability of neural network. After the RBF neural network structure design and the sample training, the model was proved to be an effective way to forecast the electronic control parameters when engine runs at steady-state fast and accurately.(2) The connecting-rod was analyzed and optimized by FEM with the data of maximum combustion pressure in cylinder obtained from the engine indicator diagram testing system. A new FEM method was introduced as:"feature model with Pro/E--before process with Pro/MECHANICA--FEM analysis with ANSYSF--strength proving--accuracy analysis and optimum with Pro/ MECHANICA". The results showed that the reliability of the connecting-rod is greatly increased after optimization. Therefore the new FEM method will benefit similar mechanic engineering problems in future.(3) The LJ276M engine's muffler insertion loss and the press loss simulation models were established. The accuracy and validity of the simulation results were verified with the test results. In order to improve the performance of the original muffler, a new design was accomplished with the help of simulation results.(4) The engine bench testing and vehicle conditions emission testing proved that the LJ276M electronic gasoline engine is better than the original one equipped with carburetor. The maximum power increases by 11%, the maximum torque increases by 9.7%, the minimum fuel consumption decreases by 3%. The emissions at ATV condition are that:CO is 1.16g/km, HC is 0,083g/km, and NOX is 0.047g/km. All the data are 30%below the critical value of CHINA stage III.