%0 Journal Article %T 高压共轨柴油机怠速循环波动特性<br>Cycle variations characteristic of high pressure common rail diesel engine at idle condition %A 韩志强 %A 任川江 %A 曾东建 %A 王 %A 海 %J 长安大学学报(自然科学版) %D 2016 %X 怠速工况因其转速低、进气充量少、残余废气系数大、缸内平均温度低、气流运动弱等特点使得燃油雾化不良，混合气浓度分布不均，循环波动较大，经济性和排放性较差，因此针对车用增压柴油机怠速循环波动特性的研究对优化怠速控制策略，改善柴油机怠速稳定性能具有重要意义。为研究喷油压力、喷油定时以及冷却液温度等对高压共轨柴油机怠速循环波动的影响，在1台4缸水冷高压共轨柴油机上进行了怠速工况循环波动试验，通过测量连续多个循环的缸内压力统计获得的最大爆发压力Pmax、最大爆发压力对应转角φmax、最大压力升高率（dP/dφ）max的循环波动率CoV和波动率δ来评价发动机的循环波动。研究结果表明：怠速工况下，随着喷油压力的增加，缸内燃烧提前，最大爆发压力及其对应转角的循环波动率分别由2.9%、0.2%增加至4.2%、1.9%；在喷油定时从-2°ATDC增加至-14°ATDC的过程中，缸内最大爆发压力的循环波动由3.2%下降到2.3%然后再增加至3.5%，呈现出先减小后增加的变化趋势；怠速循环波动对冷却液温度变化比较敏感，当冷却水温从30 ℃增加到50 ℃时，缸内最大爆发压力波动率δPmax和循环波动率CoVPmax均急剧下降，而冷却水温进一步增加，怠速循环波动逐渐减弱。<br>Idle condition might makes bad fuel atomization, uneven mixed gas concentration distribution, larger cycle fluctuations, and poor economy and emissions because of its low speed, less intake charge, more residual gas coefficient, low cylinder mean temperature and weak air movement. Therefore, the research of idle cycle fluctuation characteristics of turbocharged diesel engine is important for the optimization of idle speed control strategy, and improvement of the stability performance of idle diesel engine. To examine the influence of different injection pressure, injection timing and coolant temperature on cycle-to-cycle variation at idle condition, an experimental study was conducted on a 4-cylinder water-cooled high-pressure common rail diesel engine. The cycle fluctuation of the engine was evaluated by measuring the maximum cylinder pressure, the corresponding crank angle, the cycle fluctuation rate of maximum pressure rise rate, and the fluctuation ratio of the continuous cycle. The results show that at idle condition, the combustion can be advanced and the coefficient of variation (CoV) of maximum cylinder pressure (Pmax) and its position (φmax) increase from 2.9% and 0.2% to 4.2% and 1.9% respectively with the increase of injection pressure. The CoVPmax falls from 3.2% to 2.3% and then increases to 3.5% with the increase of injection timing from -2°ATDC to -14°ATDC. The experimental results also show that the cyclic variation is sensitive to temperature changes. When the cooling water temperature increases from 30 ℃ to 50 ℃, the maximum pressure fluctuation rate and cycle fluctuation rate of the cylinder decrease sharply, but when the cooling water temperature increases further, the idle cycle fluctuation is weakening gradually %K 汽车工程 %K 高压共轨柴油机 %K 怠速 %K 循环波动< %K br> %K automobile engineering %K diesel engine %K idle %K cyclic variation %U http://zzszrb.chd.edu.cn/oa/DArticle.aspx?type=view&id=201409055