Parameter Optimization Of Automotive Powertrain System Based On Torsional Vibration

With the continuous improvement of the automobile industrial development and people’s living standards, the requirement of people to the performance of the car is not only power, economy, security, but the increasingly seeking to the improvement of ride comfort (NVH). Aiming at the low speed car roar problem caused by a FR vehicle powertrain torsional vibration and in order to solve the problem of internal noise, this paper have optimized the parameters of power transmission system to controlling the torsional vibration of the vehicle.Aiming at the problem of this paper, this paper establishes two kinds of optimization strategies. The one is single frequency multi point optimization that the objective function is the two order torsional angle amplitude of the main reducer input end and the flywheel end are the smallest, when the engine speed is 1500rpm. The another is broadband multi-point optimization that the objective function is the two order torsional angle amplitude of the main reducer input end and the flywheel end are the smallest, when the engine speed is range from 900rpm to 3000rpm. Based on these two kinds of optimization strategies, the optimization mathematical model of the power transmission system is established and the common optimization methods are introduced.According to the characteristic of the requirement of high accuracy and small target number of the single frequency and multiple points optimization, the rigid flexible coupling model of the power transmission system is established by the traditional modeling method. Through simulation calculation, having grasped the torsional vibration characteristics, and the validity of the model is verified by comparing with the experimental results. On this basis, in ADAMS/insight module, this paper has used Box-Behnken design, central composite design (CCF), D-Optimal design, Latin hypercube design to carry out simulation test, after comparing the results of DOE simulation test, the Latin hypercube method is used to carry out the single frequency and multiple points optimization of the power transmission system, the optimization effect is obvious.According to the characteristics of the complex process and the large target number of broadband multiple points optimization, and the torsional vibration calculation theory, the lumped mass model of the power transmission system is established in MATLAB, through simulation calculation, having grasped the torsional vibration characteristics, with the comparison of rigid flexible coupling model calculation value and experimental value, having verified the accuracy of the model, the advantages and disadvantages of the two kinds of simulation models are also analyzed and compared. On this basis, the Pareto genetic algorithm in MATLAB is used to carry out the broadband multiple points optimization of the power transmission system, the optimization effect is obvious.The single frequency and broadband multiple points optimization results were compared, finding that broadband multiple points optimization effect is good, the optimization period is short, and the operation is simple, so increased about half shaft stiffness of two variables using broadband multi point of transmission system to further optimize, the optimization effect is further improved, and finally determine the scheme as the optimal solution.In summary, in order to solve the problem of noise caused by torsional vibrations inside the car, in this paper, the power transmission system is optimized by single frequency and broadband multiple points optimization, by comparing and analyzing the broadband multiple points optimization is better. On the basis of the above, the optimal scheme is given. The above work can not only directly conduct the rectification of object vehicle, but also provide reference to analyze and solve the similar problems.