改善柴油机扭矩特性的探讨

Study on the Improvement of the Torque Characteristics of Diesel Engine

为了提高柴油机的扭矩储备系数,作者通过对喷油泵出油阀削扁密封锥面、削扁减压环带进行大量的试验,最后选择了削扁密封锥面和削扁减压环带相结合的改进方案,并对这种改进后的出油阀进行了喷油泵试验和配机试验.试验结果表明,改进后的出油阀提高了喷油泵的平均有效喷射压力和高压油管内的压力传播速度,增加了最大扭矩工况点的供油量,同时能保持标定工况时供油量基本不变,这使柴油机的扭矩储备系数大大增加.配机试验还表明,改进后的出油阀在提高柴油机动力性的同时,能够保持燃油消耗率和低速时的烟度值基本不变.

The performance of the fuel injection system has a direct effect on the combustion and emission of diesel engines;the velocity characteristic plays an important role during the engine-pump matching process,and the fuel injection characteristic of the fuel injection systemis closely correlated to the performance of the whole vehicle.The pump is the key component of the fuel injection system,and we have developed several ways including the modification of the fuel delivery valve,the modification of the plunger and the modification of the speed regulator to improve its pepformance in order to adapt it to the request of the diesel engine.The author has done plenty of experiments on the fuel delivery valves with flat-cut sealing cone-shaped surfaceon,the fuel delivery valves with flat-cut sealing decompression zone,and on the fuel delivery valves with reduced-sized decompression zone.The first two methods are applied together into the final modified valve.The results reveal that the improved fuel valve can improve the fuel injection pump's average effective injection pressure and increase the diffusing velocity of the pressure wave in the high-pressure pipe.It can also increase the torque reserve coefficient without fuel rate and stack gas increase.