Improvements Of The Design Method Of Transient Driving Cycles For Passenger Car

Vehicle driving cycles is based on the investigation of vehicle's actual driving conditions and the analysis of the experimental data, and established by statistics methods. Vehicle driving cycles is a core technology of vehicle industry. Studying and developing Vehicle driving cycles based on the traffic characteristic of our country cities will provide basic data for calculating the vehicle emission and fuel comsuming and developing new vehicle types, as well as evaluating the risk mensuration of traffic control.Many universities and scientific research institutions have studied on the design method of vehicle driving cycles. But these methods all have some problems. Learned from the international advanced design methods of vehicle driving cycles, The vehicle operation simulation group of Jilin University process the original experimental data using the principal component analysis method and the fuzzy cluster theory and develop the design method of transient driving cycles according to the satisfaction criterion model and the genetic algorithm. But they only propose the combined design method of short microtrips and have not considered about microtrips that last for long.Based on the combined design method of urban transient driving cycles for passenger car, the paper takes the experimental data of passenger car driving on the real road of Beijing as study object, considering the long trips, develops the tactic design method of transient driving cycles with nonvanishing endpoints microtrips for passenger car. The following works is studied mainly in this paper :1. Based on the analysis of the historical data of driving conditions in Beijing, the actual driving conditions of the passenger cars is investigated. The data contains the velocity, the accelerator pedal opening, the brake pedal opening, the fuel consumption, the engine speed and the gear shifts information is collected by instruments along the representative routes. By preliminary analyzing of the original experimental data, the driving characteristic of passenger cars in different regions of Beijing is analyzed with the average velocity and the two-dimension velocity and acceleration distribution figure of each region.2. Based on the analysis of the long trips of the original experimental data, the definition of the microtrip is extended. By processing the data with the new definition, the microtrip original database is established and the referenced information of driving cycles including fuel consumption of one-hundred-kilometer and gears using rate is obtained. The referenced information of driving cycles provides the basic data for the tactic design of vehicle driving cycles.3. Through processing the microtrip original database using the principal component analysis method, three principal components of each microtrip are obtained. By analyzing the principal components of microtrips using the fuzzy cluster theory, the microtrip clustering database is established.4. The coherence of the two-dimension velocity and acceleration distribution figure is taken as the evaluation object. Considering the microtrips with nonvanishing endpoints, the fitness-function of the genetic algorithm based on the satisfaction criterion model is redesigned to implement the arrangement of microtrips. The coherence of gears using rate is added to the evaluation index system of the designed driving cycles.5. The genetic algorithm toolbox is used to solve the problem. According to the different satisfied value of the designer, two designed cycles of different time length (900s and 1200s) which contains the gear shifts information are obtained. Through the contrast with the other two different designed cycles established by using the the microtrip's primitive definition and the primitive fitness-function of the genetic algorithm, the necessity and rationality of extending the microtrip's definition and redesign the fitness-function of the genetic algorithm is validated.6. Through the compare of different simulation experiments on the VOSS (Vehicle Operation Self-orgnization Simulation) platform, the rationality and correctness of the two designed cycles is validated, which indicates that these designed cycles can be used to bench test and vehicle field test. Consequently, the validity and feasibility of the genetic algorithm's fitness-function redesign is validated.7. Through the compare of the designed driving cycles with the international standard driving cycles, the character of Beijing's passenger car driving cycles is analyzed.