Study On The Evaluation Of Electronic Controlling Diesel Engine Adaptability On Altiplano

Vehicle Performance Evaluation on altiplano is a kind of vehicle adaptation evaluation. It includes fuel economy, emissions and driving, and the diesel engine starting performance, idling stability and reliability affected by the altitude. The evaluation is important in the development process of new products.China's vast territory, from east to west, from south to north, the terrain changes significantly, such as Shanxi and Mongolian Plateau general altitude is 1,000m, Yunnan-Guizhou Plateau 1,000–2,000m , the Qinghai-Tibet Plateau 2,500-4,500 m, in some areas more than 5,000 m. Diesel engines used on heavy truck generally work at an altitude of below l000m, turbocharged diesel engine can performance basically un-affected at an altitude of 3,000m below. The diesel engine exclusively for the Plateau region is able to adapt to the altitude of 4,000m , even reached to 5,000m.The influence of Plateau climate conditions impact on engines has two main aspects:1. the problems arising from the high altitude:1) thin air makes the feed rate reduce, reduces air-fuel ratio, bad combustion, engine power decreased, smoky, carbon deposition serious, oil failure fast lubrication deteriorate, aggravated wear parts, exhaust temperature increased, resulting in engine failure rate increased;2) air density decline caused supercharger speeding, failure;3) low pressure caused lower boiling point ,cooling capacity deteriorated, cavitation intensified;4)the burst and fatigue problem of seals and rubber pieces in low-pressure2. The problems arising from the low temperatures:1) the oil viscosity increased, liquidity worsen ,friction bigger ,engine starting difficultly, and some load fuel consumption increased; 2) low temperature made the battery charge and discharge chemical reaction slow, thereby charging difficultly, discharge capacity smaller, starter power smaller;3) seals aging at low temperature.With diesel engines popular in the plateau region, technicians take a wide range of measures to improve diesel engines to reduce the influence of altitude as much as possible. The naturally aspirated diesel engine is very sensitive to altitude, ordinary diesel engine performance will deteriorate rapidly once used on the plateau with the altitude increasing. Main reason is with altitude higher, the air pressure lower, air density decreased, the engine inflatable declined, when diesel fuel is injected into the cylinder, the cylinder temperature and pressure are low, the time required for the extension of diesel combustion is prolonged, leading to engine working rudely, engine power dropped, fuel consumption increased. Coupled with the oxygen scarcity in cylinder and over-density mixture gas, the fuel consumption is further increased. According to tests, with altitude each addition of 1,000m, the driving force of diesel will drop 8%, fuel consumption increase 5%. To enable naturally aspirated diesel engine in the plateau region to work, we have to take certain measures, such as readjusting the supply advance angle, the controlling of the injection pump oil through the expense of the vehicle driving force, to get good use of effects.With the use of on diesel engines, the coefficient of engine inflatable is largely increased, mixture tends to be normal proportions, combustion is so improved, torque increased 20-30%, fuel consumption dropped 5-10%, restoring power in plateau. But turbo technology itself exist principle limitations. At low speed, the exhaust energy is smaller, supercharger slowing down, and inspiratory gas is insufficient, all of these hold back the engine torque to increase. Therefore, the application of turbo technology increases plateau adaptive capacity, but the oil supply system still needs to be adjusted to optimize engine performance both in low-speed and the high-speed zones. Plateau machine is debugged for the special plateau climatic conditions and the vehicle is known as Plateau vehicle. The law of supply of plateau machine is open-loop controlled which can work only in limit target altitude for a match. With the same laws of supply in all altitudes, this leads to considerable limitations. When used in the lower elevation, it is unable to restore the suitable laws of supply, vehicle performance is poor, and the driver feels bad. With the emergence of diesel engine equipped with management system we can adjust the supply at any time through detecting the inlet pressure, so that the diesel engine will always maintain optimal performance. Used in high-altitude areas, based on ECU inlet pressure parameters, we can adjust the pre-calibration parameters, and the supply of diesel engines to attain performance as good as possible. When traveling to the plains region, the ECU detects inlet pressure returning to normal, adjust the relevant parameters, so to release the ability of diesel engine. In other words, with a diesel engine management system in the plateau region and the plains the supply can switch at any time, obscuring the plateau and plain-machine concept. For vehicle manufacturers, unless targeting special user groups, there is no necessity to further develop plateau cars, only to improve the engine management system calibration, could gain a wide range of altitude, so as to enhance the competitiveness of their products and reduce product development costs.This paper is based on experiences of FAW Technology Center developing plateau vehicle in recent years and the calibration of CA6DL2-35E3 Electronically Controlled Diesel vehicle which meets State III emission standards to discuss the evaluation methods of plateau adaptation and the control methods of performance indicators, and strive to find a simple practical ways to improve as much as possible-the level of control calibration and shorten the calibration cycle and reduce development costs. And in the calibration process, explore the vehicle performance characteristics to provide decision for decision-makers and help sales departments formulate marketing strategies.Through this study, summed up the plateau electronically controlled diesel engine performance evaluation methods, FAW establish their own evaluation system.According to this evaluation method, J6 commercial vehicle CA4180P66K2A matching CA6DL2-35E3 electronically controlled diesel obtains good plateau and plain performance indicators after two rounds of calibration and adaptability tests of 450,000km and gains assessment of FAW and Bosch Corporation, July 15, 2007 is formally in mass production.