Drivability And Fuel Economy Analysis For Gear Ratio Optimization Of A Sport Utility Vehicle

Proper matching of automotive powertrain parameters is crucial to its available drivability and fuel economy. Based on commercial CAE tool GT-SUITE, this paper optimized the powertrain gear ratios of a Chinese Sport Utility Vehicle (SUV) Land wind X8, aiming at both improving its drivability and fuel economy.Vehicle modeling, drivability and fuel economy simulation were performed for Landwind X8using GT-SUITE; Comparison of the simulated data and the test data shows that the max relative error of drivability performance indices is2.52%, while that of fuel economy performance indices is2.32%, i.e., both errors are within3%. Thus, the CAE models established are accurate and reliable.Based on the validated models and the design of experiments approach (DOE), power train gear ratios were optimized aiming at improving vehicle arivability and fuel economy performance, the best gear ratios combination was obtained. Following simulation and comparison demonstrates that the maximum vehicle speed has improved by6.2%, the largest climbing grade has improved by11.4%and the0-100kM/h acceleration time has shortened by8.8%, while the mean constant-speed fuel consumption of the vehicle has dropped by1.75%and the NEDC fuel consumption has dropped by1.5%. Therefore, with the best gear ratios obtained, drivability of Landwind X8could be significantly improved, while the fuel economy could also be optimized, the best gear ratios obtained could be very helpful in later engineering implementation.By means of establishing model series and analyzing using combined static and dynamic approach, both accuracy and reliability of the CAE results were significantly improved; the obtained optimization results were also of satisfaction by meeting the customers’ needs on vehicle performance of modern city SUV.