摘要
基于增压直喷汽油机，通过实测缸内压力信号，探讨了其燃烧放热规律，着重分析了转速和负荷对气缸压力和放热率的影响。试验结果表明：当发动机负荷较低（20％～50％）时，负荷升高，缸压峰值明显增大，缸压峰值对应的曲轴转角变化存在较大波动，转速对缸压峰值的影响均较小；当发动机处于较高负荷（50％。100％）时，负荷进一步提高，缸压峰值对应的曲轴转角逐渐推后，最大缸压增大幅度趋于缓慢，且转速对缸压峰值的影响趋于明显。发动机转速增大，瞬时放热率峰值逐渐减小，随着负荷的增大，放热始点推后；在60～80°CA范围内，由于缸内工质吸热，导致累积放热率略有下降。
Based on the turbocharged GDI engine, by measuring cylinder pressures, the rules of heat re- lease rate have been studied, and this paper concentrated on analyzing the effects of engine speed and load on cylinder pressure and heat release rate. Results show that when engine load is relatively low （about 20- 50% ）, with the increase of load, max cylinder pressure increases obviously, the crank angle of max cylin- der pressure changes visibly. The effect of engine speed on max cylinder pressure is unconspicuous. When engine load is relatively high （about 50-100% ）, with load increasing, the crank angle of max cylinder pressure increases, cylinder pressure＇s rate of increase tends to mild, and the effect of engine speed on max cylinder pressure tends to be obvious. With engine speed increasing, maximum of transient heat release rate decreases. With engine load increasing, the initial point of heat release rate is postponed. Because of heat absorption of mixture in cylinder, the accumulated heat release rate decreases mildly between 60 to 80 °CA ATDC.
出处
《小型内燃机与车辆技术》
2015年第3期6-10,共5页
Small Internal Combustion Engine and Vehicle Technique
基金
国家高技术研究发展计划(863计划)资助项目(2012AA111702)
国防重点实验室基金(9140C330203120C33120)
关键词
涡轮增压
缸内直喷
汽油机
气缸压力
放热率
Turbocharged, Direct injection, Gasoline engine, Cylinder pressure, Heat release rate
