Study On The Driving Cycle Of Wuhan City Bus And The Duty Cycle Of The Engine

Driving Cycle and Duty Cycle are mainly applied on the evaluation of the vehicle and engine performance. So in order to make an accurate evaluation on the fuel economy and emission level of the vehicle and engine, the driving cycle and duty cycle have to represent the real condition of the vehicle and engine. Then whether the evaluation on the fuel economy and emission of the vehicle is reasonable or not will directly affect the fuel economy and emission optimization of the vehicle and engine.The Wuhan city bus was chosen as the study target. Based on the vehicle field test, the muti-statistic method was used to develop the driving cycle that can represent the real condition of the Wuhan city bus. And the theory model and field test were used together to validate the developed driving cycle. Then the analysis on the city velocity distribution of the city bus, the speed distribution and torque distribution of the engine were made. At last, the duty cycle of engine was developed depended on the test results. The main tasks covered by this paper as follow:(1) Decision on the test procedure of the Wuhan city bus. This part including the choice of the test road, the establishment of the field test equipment and the calibration of the sensor.(2) Development of the Wuhan city bus driving cycle. In this part, the methods that are applied to develop the driving cycle of the vehicle were analyzed. Then, the method used to develop the driving cycle of the city bus was confirmed and the program of synthesizing the driving cycle was developed. At last, the distribution probability model of the velocity, speed and torque was developed and the factors that affect the average velocity of the bus were discussed.(3) The validation on the validity of the driving cycle was made. In this part, the work flow of establish the vehicle simulation model by AVL CRUISE was introduced and based on the acceleration test and fuel economy test, the vehicle simulation model was calibrated. At last, the simulation results were compared with the test Stat. results to confirm the validity of the city bus driving cycle.(4) Development of the engine duty cycle. In this part, the field test results related to the engine duty cycle was analyzed and based on the stat. results, the duty cycle (15 mode cycle) then can represent the real working condition of the engine installed on the city bus was developed. And the validity of the duty cycle was confirmed by engine bench test.