Load expansion of a dieseline compression ignition engine with multi-mode combustion

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• 作者：Fuyuan Yang ; ^{fyyang@tsinghua.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Changsheng Yao ; Jinli Wang ; Minggao Ouyang
• 关键词：Dieseline ; Load limit ; Partially premixed compression ignition (PPCI) ; Low temperature combustion (LTC) ; Multi-mode combustion
• 刊名：Fuel
• 出版年：2016
• 出版时间：1 May 2016
• 年：2016
• 卷：171
• 期：Complete
• 页码：5-17
• 全文大小：870 K

文摘

This paper presents a study on the upper load expansion and combustion characteristics of a multi-mode combustion engine with dieseline. The partially premixed compression ignition (PPCI) mode with early direct injection and late-injection low temperature combustion (L-LTC) mode with near-top dead center (TDC) direct injection are studied and compared at various loads with sweeps of injection parameters and exhaust gas recirculation (EGR) rates. A single injection strategy and a double injection strategy with small pilot ratios are tested. For both combustion modes, the criteria are set to identify the load limit of clean combustion. The NO_x limit is 200 ppm, and the particulate matter number limit is 100 × 10⁶/cm³. The maximum pressure rise rate is lower than 0.8 MPa/°, and the maximum cylinder pressure is below 16 MPa. In addition, the coefficient of variation for the indicated mean effective pressure (IMEP) should be less than 3% combustion stability. The results indicate that L-LTC has a higher load limit than PPCI for all the test fuels; therefore, the upper load limit of PPCI can be increased using L-LTC. However, the thermal efficiency of L-LTC is lower than that of PPCI. Therefore, a multi-mode combustion strategy is proposed to be the best option for the whole load range. For the small to medium load range, PPCI can achieve a low emissions level and with a higher thermal efficiency than L-LTC; therefore, PPCI is an ideal choice for this range. For the medium to high load range, the L-LTC mode is the only suitable mode due to its low emissions. In the high load range, a simultaneous reduction in NO_x and PM is not possible for both PPCI and L-LTC; therefore, the conventional CI mode has to be used to ensure high fuel economy performance.