Song Baoyu

Optimization of parallel regenerative braking control strategy

Regenerative braking system is the own system of electric and hybrid electric vehicle. The system can restore the kinetic energy and potential energy, used during start and accelerating, into battery through electrical machine. The total brake force is composed of friction brake force on front axel, friction brake force on rear axel and regenerative brake force when a vehicle equipped with regenerative braking system brakes. A control strategy, parallel regenerative brake strategy, was proposed to resolve the distribution of the three forces. The parallel regenerative brake strategy was optimized on Saturn SL1 and then simulated under urban 15 drive cycle. As a result, through optimization the parallel brake strategy is not only safe enough but also can restore the largest amount of the brake energy.

Effect of two-phase liquid lubricant on fatigue life

Abstract This paper investigates experimentally the effect of two-phase liquid lubricating oil with solid additives of carbon or graphite or polytetrafluoroethene (PTFE) powder on contact fatigue life. The results show that the greater the amount of the three additives mentioned above, the longer the contact fatigue life becomes, but after the amount of graphite is greater than 0.5%, the contact fatigue life becomes almost a constant value. It is thought that the mechanism to prolong the fatigue life exists in four aspects: increasing effect of viscosity, decreasing effect of Hertzian contact stress, wedge effect of additive grains and adherent effec of additives on the contact surface.

Optimum design of automobile diaphragm spring clutch

In order to meet the design requirements and characters, the optimum mathematical model of a light carry truckpsilas diaphragm spring clutch is established to decrease its size as far as the engine torque is reliably transferred. The truckpsilas clutch design is optimized by MATLAB optimum toolbox. The 3-D model of the optimized results is established by Pro/E and the finite element analysis is carried out. Itpsilas proved that the design period can be shortened, the clutch size can be decreased and the production cost can be lowered.

The Research of Regenerative Braking Control Strategy for Advanced Braking Force Distribution

Regenerative braking system is the characteristic system of electric and hybrid electric vehicle. The system can restore the kinetic energy and potential energy, used during start and accelerating, into battery through electrical machine. A control strategy witch is based on ideal braking force distribution is proposed. Front wheel and rear wheel can make full use of ground adhesion condition with the strategy when the vehicle brakes. More regenerative braking energy is reclaimed on the premise of ensuring braking efficiency. A simulation model is built in ADVISOR, and then put in vehicle model to simulate. The result proves that more effective braking energy is reclaimed and vehicle fuel economy is improved.

A harmonic injection SPWM method for the high-responsive PMSM control system

In a permanent magnet synchronous motor (PMSM) control system, usually, the phase voltage instruction is limited independently to prevent a three-phase pulse width modulation (PWM) wave from overflowing. This method decreases the efficiency of the bus voltage and causes voltage vector direction errors. To solve these problems, we propose a harmonic injection sinusoidal pulse-width modulation (SPWM). This method uses harmonic injected sinusoidal PWM to improve the utilisation ratio of the bus voltage, and consequently improve system performance. In this paper, we analyse the problem in terms of potential difference. The simulation results show that the proposed method can increase the utilisation ratio of the bus voltage up to 15.4%, and the voltage vector mode obtained with the proposed algorithm is larger than that obtained with the conventional one. The method with harmonic injection consequently improves current response, without affecting voltage vector accuracy. The experiment results validate the proposed method.

Study on loading capacity of the coating-substrate system of vapour-deposited TiN and TiC on bearing balls II. Rubbing method in experiments and analysis

Abstract The critical load of failure Lc is an important index for the loading capacity of a coating-substrate system. In consideration of the fact that a coating-substrate system in practice may take any one form of the four failure modes, coating failure, substrate yielding, interfacial failure or the mixed failure, this paper defines the critical load of failure of a coating-substrate system as the maximum normal load under a certain friction coefficient before any failure occurs. It also puts forward a new method, the rubbing method, to measure Lc. A multifunctional tester, Model CM-1, is developed on the basis of this method. The critical loads of bearing balls with physical vapor deposited (PVD) TiN or chemical vapor deposited (CVD) TiC or CVD TiC + Ti(CxNy) + TiN coatings under different friction coefficients are tested on this machine and their failing processes are analysed. The results show that the rubbing method is a sound new method for the measurement of Lc, and the results agree well with the those of field effect microscopy. The Lc of the CVD coating is greater than that of the PVD coating, and the Lc under smaller friction coefficient f is greater than that under larger f.