Research And Development Of Hill Start System For Heavy Truck With AMT

The AMT (Automatic Mechanical Transmission) has attracted increasing interest from automotive research. Compared to traditional Manual Transmission (MT), the AMT can improve the driving comfort and shift quality. Compared to other types of automatic transmission, such as AT (Automatic Transmission), CVT (Continuously Variable Transmission), etc., AMT has some advantages such as low cost, hight efficieny, etc. The AMT can be manufactured on the traditional manual transmission manufaction line. Therefore it will spread over China in recent years with low investment.Hill starting is encounted frequently when driving. For the manual transmission, the quality of hill-start shows whether the driver is skilled. For the AMT, the quality of hill-start is the key evalution index to show the competitive advantage. A large numer of experiments were carried out to study the performance of the vehicle when start up on the slop road. Based on the analysis for the manual transmission and the performance of the truck equipped with AMT, hill start control strategy was proposed in the dissertation. The control strategy includes the controller of the cluch and brake.There is little research publishing on the evaluation of the hill start for the heavy truck. It is very necessary to build an evaluation system for the hill start. It is very helpful for the development of the AMT. This paper proposed an evaluation system for the hill start. A large number of experiments are carried out to get the subjective value. The correlation of the subjective value and objective value was studied. And the method to get the subjective value from objective value was proposed in the dissertation.The dissertation presents a detailed AMT model composed of various components from multi-domains like mechanical systems (clutch, gear pair etc.), pneumatic actuation systems (clutch actuation system, parking brake system, etc.). Various components and subsystem model, such as the engine, AMT, wheels, brake systems etc., are integrated into an overall vehicle system model according to the transmission power flow and control logic. The simulaion with the control strategy was carried out to study the performance of the hill start. The performance on the road with 5% and 16% is very well, and shows the correctness of the control strategy. The dissertation developed a hill-start system based on a 4*2 truck. The system includes parking brake system, hill start magnetic valve, the software and hardware of the transimission control unit (TCU), etc. The experiment show that SHS developed in this paper can aviod the coasting, and can gain a good quantity for hill-start.