| Recently, with implementation of the "Western Development" strategy and a large number investment in the infrastructure, transport vehicles and construction machinery which is suitable for high altitude area get more and more attention. As the heart of these vehicles and machinery, the engine which has or has not the performance of the plateau adaptability also get more and more attention. Since the end of last century, the engine has evolved from the original naturally aspirated engine to a turbocharged engine and then to intercoolant turbocharged engine. The performance of the plateau adaptability has become one of the important technical specifications in the process of engine development.The CA6DE-17 diesel engine is a 6 inline cylinder, four-stroke, water cooled, direct injection and intercoolant turbocharged diesel which is jointly developed by FAW technical center and FAW Dalian Diesel Engine Branch Company based on the customer's requirement. As the customer's specific requirements, the engine must meet the application requirements in high altitude. Therefore, in the development process, the project team has set up a research group to conduct the on site investigation at Qinghai-Tibet Plateau and collect enough information about the environment and climate as input data of the diesel engine design. The project team also takes various methods to validate the engine and ensure that the diesel engine has good plateau adaptability performance.In this paper, the plateau adaptability performance of the CA6DE-17 diesel engine is studied. The main content is as following:1, Through studying large amount of materials, the environmental and climatic characteristics of the plateau region were analyzed and studied.2, According to surveys, understood and mastered the natural conditions and road conditions along the Qinghai-Tibet Highway.3, Under the guidance and the help of the instructor, read a large number of references about the plateau engine and did some research about the issues that the plateau engine occurred often. There are six main issues about the plateau diesel engine: 1), over-temperature and speed problem about the booster; 2), acceleration problem in low speed; 3), cold start problem; 4), the cooling system problem; 5), intake system problem; 6), non-metallic parts problem.4, Using CA6DE-17 diesel engine parameters as input data, built up a new model and used GT-Power to do some simulation and analysis about the engine's plateau adaptability performance. By this way, the plateau adaptability performance of the engine was well evaluated theoretically. There are two ways about the calculation: one is to maintain constant fuel supply and analysis the change of air flow under the condition of air pressure dropping caused by high altitude. The other is to ensure the minimum air-fuel ratio limit which will not cause engine smoke and analysis engine torque reduction caused by lack of air feeding. Through analysis and calculation, at an altitude of 3,000 meters, the engine can achieve the maximum power about 170 hp and the maximum torque about 620Nm. it can meet the requirement in the high altitude. However, the torque will drop at low speed because of the thin air. When the engine speed is around 1100 r / min, the engine torque will drop to 300Nm. In this condition, the joint operating line is closer to the engine speed limit line and this means that the 5,000 meters is the limit altitude for the diesel engine.5, Used one CA6DE-17 diesel engine to do high altitude simulation test in the plateau environmental Laboratory of the FAW Dalian Diesel Engine Branch company. Because the laboratory condition is limited, simulation test just can be done in 4,000 meters altitude. After the comprehensive analysis of the testing data, the following conclusions can be drawn:(1) At an altitude of 4,000 meters, the engine power at the rated point (2300 r/min) is 122.06 kW and just 3kW lower than the rated power 125 kW. It is within the tolerance and nearly reaches the maximum power of 125 KW. The engine can meet the plateau use requirements;(2) At an altitude of 3,000 meters, the engine torque around 1400 r/min is 589.17 N ? m, which is 31 N ? m lower than the maximum torque and within the allowed tolerances. At an altitude of 4,000 meters, the engine torque at 1400 r/min is just 411.88 N ? m. But from the view of engine performance characteristics map, the engine torque at 1500 r/min is about 550 N ? m and the engine can meet requirements used in the plateau basically.(3) Above the altitude of 2000 meters and at the low speed about 1100r/min, the engine torque drops because of the thin air. At an altitude of 4,000 meters, the engine torque is 330.78 N ? m. It will cause the reduction of vehicle load capacity and grade ability. At the same time, the vehicle fuel economy becomes worse because of the sharp increase in fuel consumption. But it will not affect the normal use in the plateau and the engine just run in the low speed.(4) The maximum speed of the turbocharger is 120000 r/min and within the allowable range. There are no over-speed and over-temperature problems. Therefore, the CA6DE-17 diesel engine can meet the whole application requirements in plateaus and have a good plateau adaptability performance below the altitude of 4,000 meters.6, Tested the truck CA1122P1K2S which is equipped with CA6DE-17 diesel engine in the plateau region. The main testing items are power test, starting test, idle stability test, engine function test and turbocharger characteristics test, ETC. The maximum testing altitude is 4086 meters. By comparing the test results with those in the plain areas and after comprehensive analysis, the following conclusions can be drew: The starting time of the truck CA1122P1K2S in the plateau is longer than in plain areas and there is the phenomenon of black smoke. The power is also lower than in plain areas. The fuel consumption in the constant speed and other working conditions is higher than in the plain areas, but the variation is small. The real vehicle test results, calculation results, simulation results are basically consistent. Therefore, the CA6DE-17 diesel engine meets the user requirement under adverse environmental conditions such as the cold and hypoxia high altitude environment below the altitude of 4,000 meters. The engine has a good plateau adaptability performance.
|
PDF Full Text Request