Study On The Prediction Method Of The Fuel Economy Of The Vehicle Based On The Real-time Performance Of The Engine

The improvement of the vehicle fuel economy is an important goal to achieve energy savings, and it depends on the measurement accuracy of vehicle fuel consumption. However, the methods of measurement in most countries are based on engine fuel consumption, and the measurement based on vehicle in the actual operating conditions is still an unsolved technical problem. In addition, the using of simulation methods to forecast vehicle economy in vehicle development stage requires detailed test data like engine universal characteristic as a support, which leading to high development costs and long development cycle. The accurate prediction of engine fuel consumption in all operating conditions is the key to solve the problem.In this Paper, the study of the links between vehicle and engine economic is based on the vehicle theory. Based on the internal engine theory and engine performance Parameters database, the internal relations between engine performance Parameters and operating Parameters is analyzed, the common law of engine operating Parameters is summarized, powerful simulation abilities of GT-SUITE is used, and new methods to forecast fuel economy is proposed.First of all, according to the vehicle kinematics general equation, this Paper determines the factors affecting vehicle movement, describes the relationship between the vehicle economy and engine performance Parameters, establishes theoretical basis of forecasting vehicle fuel economy. Secondly, this Paper analyzes the internal relations between engine performance Parameters and operating Parameters and determines the key operating Parameters which have an impact on engine performance, the summary and analysis of common law is made based on the three advanced turbocharged gasoline engine bench test data. Then, this Paper proposes engine-car simulation methods to couple the common law and establishes engine-car model based on GT-DRIVE simulation model. In the last, the Paper verifies the prediction method based on fuel economy common law by using the conventional GT-DRIVE vehicle fuel economy simulation method.The results show that: the common law can reflect actual engine Part load operation conditions and the calibration of engine model can be more accurate by using it. Compared with the general economic approach, this method can forecast vehicle fuel economic without the limitation of the engine displacement, as a result, by using this method can improve R&D efficiency, shorten development cycles and reduce development costs.