The method of simulating the loading of boosted diesel engine during start-up at low ambient temperatures

The paper discusses the method of simulating the loading of boosted diesel engine during start-up at low ambient temperatures. To improve the reliability of the experimental evaluation of the results of diesel qualities the device simulating resistance to crankshaft turn over from the side of transmission elements of object was developed. The device provides the ability to control and change the moment of resistance to crankshaft turn over. The method of start-up testing of high performance engine with the device in a climatic chamber was developed. The engine is equipped with prior-start preparation and start-up facilitation systems. Loading parameters for type 12ChN15/16 engine object. In accordance with the test program 20 experiments were conducted at ambient temperatures of 5, minus 5 and minus 20 °С. The results of experimental studies confirmed the effectiveness and adequacy of the proposed method. It was revealed that crankshaft breakaway torque during engine acceleration does not depend on load of engine and oil viscosity (in the range of ambient temperatures during testing) and is determined by moment of inertia of the rotating masses. During diesel turn over load pressure is provided almost simultaneously with the start of engine crankshaft breakaway. Loading of device pump by pressure of 14 MPa leads to an increase of resistance to crankshaft turn over moment at an ambient temperature of minus 20 °С to 9% (from 883 to 970 N·m). According to the results of testing the recommendations for further improvement of the device to simulate loading of boosted diesel engine during start-up at low ambient temperatures were given.

diesel, engine starting characteristics, testing, climatic chamber, loading device