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Technical Paper

A Synthetic Control Method for Hydrodynamic Transmission with Lock-up Clutch for Chinese City Bus

1996-10-01
962175
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.
Technical Paper

Dynamic Modelling on Energy Storage System of High Speed Flywheel for Powertrain of Fuel Economy in City Bus

1993-11-01
932962
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.
Technical Paper

In Cylinder Gas Motions Via Non-Isotropic Turbulent Modeling and Experiment

1989-09-01
891915
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.
Technical Paper

Numerical Analysis of Stresses within the High Speed Flywheel in the Regenerative Braking System of a City Bus

1995-11-01
952599
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.
Technical Paper

On Dynamic Characteristics and Electronic Control of Chinese City Bus Powertrain Consisting of Hydro-dynamic Transmission with Lock-up Clutch

1996-10-01
962174
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.
Technical Paper

The Power Transmissive Principle of Saving Energy Transmission System for Hybrid Vehicles with an Energy Storage Flywheel

1990-10-01
902281
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.
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