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Gasoline ventilation process directly affect the power of the engine, fuel economy and emissions performance. In this paper, the optimization of the the gasoline intake system pipe length, cavity volume, cam and installation of variable valve device to improve the ventilation process, improve the operating point of the full load output torque, thus improving the performance of the engine's power. The first application of a one-dimensional engine simulation software GT-Power to build a four-cylinder car Gasoline work process analysis model, the calculation and analysis of the inlet and exhaust system piping length and cavity volume change of the intake pipe pressure fluctuations volumetric efficiency, summarize drawn the impact of the law, under the guidance of the law, the optimization of the intake system piping length and cavity volume. The results show that: optimizing the intake system after engine in, high-speed dynamic performance of the region has been greatly improved, but little improvement in dynamic performance at low engine speed. The original engine is traditional valve train, the valve timing can not make the appropriate changes with the engine operating conditions change, which makes low engine speeds can not take full advantage of the effect of fluctuations in the intake pipe to improve volumetric efficiency. Therefore, the analysis on the basis of a variety of variables affect the engine performance in the institutional characteristics of the typical VVT profiling with gas-phase, to determine the structure of the program based on the the camshaft phase modulation VVT implementation based on the engine camshaft phase modulation principle VVT ??technology applications. The calculation results show that the VVT ??technologies can greatly improve the low engine speed, high-speed dynamic performance, further validate the feasibility and superiority of the implementation of the VVT ??technology. In order to further improve the performance of the engine power, the fullness and buffer segment of the cam profile of the original engine optimization. The calculation results show that optimization of the line of the cam type, the pneumatic efficiency of the engine has been further improved, and pumping loss decrease, thereby further improving the power performance of the engine. Optimizes the engine's intake system pipe length, the volume of the cavity, cam and retrofitting variable valve device, the dynamic performance of the engine has been greatly improved, to achieve maximum power 94.32kW/5750r / min, maximum torque of 167.54 N ยท m / 4,000 r / min, respectively, 8.29% higher than the original machine, 5.90%, reaching the level expected by the manufacturers.
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