Analysis of Pilot Injection Strategies Effects Mechanism on In-cylinder High Frequency Pressure Oscillations in PPCI Diesel Engine

作者：Chen, Xi Ming; Liu, Long^*; Du, Jing Tao

来源：Journal of Engineering Thermophysics, 2018, 39(9): 2097-2102.

• DI diesel engine
• Heat Release Rate (HRR)
• High frequency HF
• In-cylinder pressures
• Pilot injection
• Pilot injection timing
• Pressure oscillation
• Time frequency analysis

The reasons for combustion noise of diesel engine are aerodynamic load and high frequency pressure oscillations. And high frequency pressure oscillations are the primary factor of combustion noise. In order to research the effect mechanism of pilot injection on high frequency pressure oscillations in PPCI diesel engine. Experiments were performed on a single-cylinder DI-diesel engine with pilot and main injection. A method of wavelet time frequency analysis was used to process the in-cylinder pressure data. And the high frequency pressure oscillations were performed in time-frequency figure. The results show that the influence of high frequency pressure oscillations cannot be reflected qualitatively by heat release rate in the condition of pilot-main injection. And the effects of main combustion on high frequency pressure oscillations are less than the effects of pilot combustion. Besides, the injection strategies of large pilot quantity and advanced pilot injection timing could obtain the minimal high frequency pressure oscillations. In addition, the pressure oscillations of pilot and main combustion are mainly distributed in -4∼16°CA. And frequency ranges of pressure oscillations of pilot and main combustion are mainly concentrated in 4000∼5000 Hz and 6000∼8000 Hz. And the frequency ranges of pressure oscillations of pilot combustion are larger than that of main combustion.

• 出版日期2018
• 单位哈尔滨工程大学