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Starting from the real vehicle working conditions and taking that engine works at the optimum economic line as a foundation, this paper gives the power transmissive principle of hybrid vehicle with energy storage flywheel working in process of accelerating, uniformly running and braking, derives the relationship of the ratio and time in continuously - variable transmission(CVT) under working conditions of adjusting engine load, recovering and releasing energy etc., and provides the theoretic foundation for transmission system of flywheel energy storage vehicle to realize optimum economic control.

A new design method is proposed for a semi-tracked air-cushion vehicle for soft terrain by using a flexible bind, which offers more flexibility in designing. This paper describes the design principle focusing on optimizing the total power consumption of the vehicle. The relationships of load distribution and power consumption are analyzed. The prototype experiments showed that the proposed design can meet the demand of tractive and transport efficiency with its optimal state of using minimum total power consumption and meanwhile maintaining ride comfort.

A newly developed GYB-100 hydrodynamic transmission consisting of DFZFB-323 torque converter with lock-up clutch and power shift gearbox for Chinese city bus has been put into operation. The locking-up process of the torque converter is a transient one, and it will bring great shudder to powertrain and thus reduce the lifespan of the clutch. Measures must be taken to eliminate the shudder. In this paper, the city bus powertrain is supposed to be a concentrated mode, i.e, a spring-mass system having multi-degrees of freedom. From analysis of dynamic characteristics of the lock-up clutch it gives that the friction characteristics of the lock-up clutch are of main importance for avoidance of shudder and the proper control of oil pressure operating the lock-up clutch and oil-filling time will lead to improved friction characteristics. The judgement of quality of the lock-up clutch is presented. Using modern control theory, we get optimal control schedule of the lock-up clutch.

In this paper,the flywheel is considered to be linear elastic composition in accordance with its operating characteristic, mechanical and mathematical model are presented,the finite element method is employed to carry out the numerical analysis of steady and unsteady stresses within the high speed flywheel in the regenerative braking system of a city bus,and these provide the basis foŕ its structural modification and further rational design.

In cylinder gas motion of an open chamber diesel engine is modeled via a newly developed non-isotropic turbulent flow approach. The theoretical treatment is based on the turbulent kinetic energy-dissipation-random model of Reynolds stress (k - ε - R) which incorporates the non-isotropic fluctuating characteristics of gas movement during a compression stroke of a direct injection diesel engine. The validity of the model was compared to the experimental measurement obtained on an axisymmetric reentrant bowl chamber engine configuration. The experimental data fit much more closely to the established non-isotropic behavior in contrast to the traditional isotropic approach.

The city buses start and stop frequently, therefore significant amount of kinetic energy is wasted on friction plates. In order to retrieve this amount of energy, various feasible and efficient energy storage systems have been suggested by researchers to reuse the energy to improve the efficiency of the city bus. Due to small size, high energy density, cleanliness and easiness to absorb/reuse the energy, the storage system of flywheel is hopeful to be coming into wide use. In this paper, a dynamic model is analyzed to study the characteristics of the system using time series. Finally, comparison between simulation and experiment is given.

Based on the tire cornering properties in steady state condition, a theoretical model of non-steady state tire cornering properties (NSSTCP) with small lateral inputs is presented. The outputs of the model are lateral force and aligning moment, while the inputs are yaw angle and lateral displacement (or turn slip and slip angle). The deformation characteristics of contact patch are analyzed in non-steady state condition. The flexibility of tread and that of carcass are both taken into account. The deformation of carcass is assumed to compose of translating part, bending part and twisting part. The tests of NSSTCP including pure yaw motion and pure lateral motion are realized with step inputs of yaw angle and slip angle respectively and test data is then transformed into frequency domain. The model is validated through comparing the computational results with test frequency response.

The use of hydrodynamic transmission with lock-up clutch for a Chinese city bus leads to good fuel economy and ease of operation. Many examples have shown that the microprocessor-based control system used in a vehicle powertrain has the advantage with high control speed over a manual one, but most of the time, its control qualities are poor, especially when outside conditions change. In this paper, a synthetic control method for hydrodynamic transmission for a Chinese city bus is proposed with respect to control qualities of lock-up control. The lock-up control process is divided into two steps, i.e., ‘estimate’ step and ‘fine’ step, so we can apply different control schedules to realize different control demands and get better control qualities.

A generalized theoretical model of tire cornering properties is presented in steady state condition with lateral deflection of tread and complex deformation of carcass under consideration. The model is suitable for full range of vertical load and slip angle. Six parameters are defined to represent the characteristics of tire stiffness, contact pressure distribution and carcass deformation. The model is validated against test data. Some simplified models, e.g. brush model, HSRI model when longitudinal force is zero, Fiala model etc., can be derived as some specific cases of this model. The analytic model provides a sound foundation for semi-empirical expression and gains insight into study of vehicle system dynamics.