增压柴油机排气压力变化规律的实验研究

Experimental Study on the Rules of Variation of Exhaust Gas Pressure in Turbocharged Diesel Engine

研究采用等压增压系统的多缸柴油机排气压力的变化规律.利用瞬态压力传感器和燃烧分析仪,在某V型8缸增压柴油机上,测量了不同工况下第1缸排气阶段气缸内和排气道出口处的压力随曲轴转角的变化情况.分析结果表明:在相同的转速下,随着负荷增加,排气道出口压力随曲轴转角变化的规律相近,压力的波动幅度增加;随着转速的增加,在排气道出口压力曲线中的波峰和波谷出现的曲轴转角位置向后推移;在某些工况下,缸内排气压力高于排气道出口的压力,而有些工况下,缸内排气压力会低于排气道出口的压力.

The rules of variation of exhaust gas pressure for turbocharged multi-cylinder diesel engines are studied. Gas pressure at the exhaust port and cylinder pressure of the first cylinder are measured synchronously in the exhaust stroke under various operating conditions using instantaneous pressure sensor and the combustion analyzer on a V-type turbocharged eight- cylinder diesel engine. The measured results indicated that the rule of variation of exhaust gas pressure were similar under the same engine speed. Along with increased loads, the fluctuant range of exhaust gas pressure increased. Under different engine speeds, the phase of wave crest and wave trough in the exhaust pressure curve postponed backwards along with increasing engine speed. Under some operating conditions, pressures in the cylinder are higher than gas pressures in the exhaust port on the exhaust period. Under some other operating conditions, pressures in the cylinder are smaller than gas pressures in the exhaust port.