Engine Modeling And Simulation Analysis Of Power Train For Car's Equipped With CVT

Automobile has been invented for more than a century in the world. In thelast one hundred years, the technology of automobile had been fast developed. Inthis century, with the increase of peoples living level, the quantity of automobileincrease year-to-year. The environment problems and energy problems caused bythis have troubled many countries'people. It has become an important task for thescientists of automobile technology in the world that how to improve the vehicle'seconomic performance and reduce the harmful exhaust emission.The drive line system design will affect the automobile economic feature,accelerate feature and exhaust feature. The virtue of the drive line system designis the transmission design, for the drive line system change the transform ratiothrough the transmission. The Metal-belt Continuously VariableTransmission(Metal V-belt CVT) can be regarded as the most ideal transmissionwhich cannot be replaced by other types of transmissions, because of itssimplicity and compact structure, easiness to operate and high performance, whichis developing rapidly for its specialty. There will be also a great developingpotentiality and extensive market in China. But in the past, the CVT was limitedby the material problem and machining techniques problem. At present, almost allthe problems have been solved. In addition, with the environment protect andenergy saving idea having been more and more required, the CVT can be moreand more recognized and many automobile manufactories in the world begin toresearch and develop it. In this paper, I analyze and discuss something about theratio control system of Belt-CVT. On the basis of some imitate and experimentsfor it on the CVT experiment platform. First of all, through the matching petrolic'sspeed characteristic test, I can found the numerical model of motor. After thesemodels had been applied to the control system of CVT, I got the object speed ratioand designed the PID controller which can control the variable of speed ratio.Through the imitate model of the entire cars, I analyzed the power capability'schange of the entire cars. In addition, I proved feasibility of the PID controller inthis paper through the correlative bench test. This paper had mostly studied on the petrol engine and CVT, the specificwork is as follow: 1. At first, I have read large quantity of respect references information fromnation and foreign articles. Then I depicted the status, action of drive system aswell as the develop history and forthcoming development trend of thetransmission. In addition, I introduced the basic structure, operation principle ofCVT. And I emphasized the rationale and the control technique of transmission,which supplied the rationale for the research of the CVT's behavioral in thispaper. 2. Load bearing characteristic and speed characteristic is different towarddifferent engines. So the object speed ratio was also different. Matching enginewas studied in this paper. Firstly, according to different throttle angle, carry outthe universal character experiment of this matching engine through speedcharacteristic test. And then analyses the extraneous factors which impacted theengine performance, and did modification process about test data. Secondly, usethe experiment data to build the torque numerical model, gasoline consumptionnumerical model and universal characteristic of the engine using formula fittingprocess. And then speed adjustment characteristic of the engine can be founded,which was the foundation of achieving the best economy and the best powerability for CVT system and the warranty of realizing and simulating of control inCVT system. 3. According to the engine's numerical models, I came up with the besteconomy and power object speed ratio fig of the entire car. Using the lumpedmass method, power driving system has been reduced to the model system whichpossessed two rotating mass. Take no account of the specific implementationprocedure of speed ratio controlling in the transmission, I took the control systemof speed ratio as an ideal system, analyzed the algorithm of the rate's change onspeed ratio, and designed the simple and practical PID controller at the same time.The three controlling parameter as proper, integral, differential was ascertained bysimulation analyses and compares several times. A simulation analysis is theindispensable instruments to analyze the theory in the stage of new production'sdevelopment without forming the test conditions. According to the numericalmodel of engine, the best power capability object speed ratio model, the besteconomy capability object speed ratio model, dynamic model of CVT andparameters of the entire cars, I found the simulation model of the entire car thatequipped CVT in this paper, which included engine sub model, object speed ratiosub model(the best power capability object speed ratio sub model and the besteconomy capability object speed ratio sub model), controller sub model of speedratio, sub model of CVT and entire car. In accordance with this sub models, Iprecede the simulation analyses of power capability on the starting condition,accelerate condition and suffering resistance of the ground as accelerating. 4. Test is an important part in the research of the science. Test is to proof ifthe analysis of the theory is right. In the pedestal test of CVT, I preceded thefollowing test on the constant speed ratio for 0.5, 1.4, 2.3 to demonstrate therationality of PID controller which was designed in the paper. Because of theconfine of the test condition, I haven't done the test of an entire car, and haven'tdemonstrated the power capability simulation analyses on the entire car. The innovation of this paper is as follow: I did the speed characteristic testusing matching engine in the paper at the first time and got the engine numericalmodel, which was the theoretical basis of the next development work on CVT. Inthe control system of speed ratio, I came up with the PID controller which hassimple control structure and is easy to set in the practical situations. The PIDcontroller was firstly used in the CVT of the paper. The result of the simulationanalysis and test has also demonstrated that the practice speed ratio has afavorable responsiveness to the object speed ratio after using the PID designed in...