4.Conclusions
In this paper, the combustion difference cylinder-to-cylinder was analyzed to study the effect of MSP, inlet air temperature and engine speed on the DMDF engine performance. The main results are summarized as follows: 1. The pressure difference cylinder-to-cylinder and the UED increases gradually with the increase of MSP under various engine load. The COV increases with MSP under low engine load, and the COV curves vary very little under low MS Punder 75% and 100% engine load, and a significantly rise appeared when MSP further increases .In the DMDF engine, theim balance of methanol entered into each cylinder is one of the main reason that causes pressure unevenness of 4 cylinders. 2. The increase of intake air temperature enlarges the difference of peak pressure cylinder-to-cylinder, and the difference is mainly caused by 1# and 4# cylinder. In the meantime, the COV of each cylinder decreases with the increase of inlet air temperature. The UED increases gradually with the increase of intake air temperature, but the UED is usually lower than 8% at various intake air temperatures when MSP is less than 40%. It suggests the inlet air temperature in the range of 35–80°C is proper when MSP less than 40%. 3. The difference of pressure cylinder-to-cylinder decreases with the increase of engine speed, and causes the UED for various MSP decreases simultaneously. And the increases of engine speed can reduce the difference of combustion phase fo r different MSP. It can be considered raising MSP at high engine speed in order to gain better engine economy.