Search Results

For the vehicle equipped with stepped automatic transmission (SAT) that has a fixed number of gears, gearshift schedule is crucial to improve the comprehensive performance that takes into account power performance, fuel economy, and driver’s performance expectation together. To optimize and individualize the gearshift schedule, an optimization method and an improved performance evaluation approach for multi-performance gearshift schedule were proposed, which are effective in terms of reflecting the driver's expectation on different performance. However, the proposed optimization method does not consider the influence of the road slope on the comprehensive performance. As the road slope changes the load of vehicle that is different from the load when a vehicle runs on a level road, the optimized gearshift schedule without considering road slope is obviously not the optimal solution for a vehicle equipped with SAT when it runs on ramp.

To improve the comprehensive performance of vehicles equipped with stepped automatic transmission (SAT), the optimization of gearshift schedule should take into account various performance such as power performance, fuel economy, etc. In addition, the SATs would become more acceptable if the optimized gearshift schedule could also be individualized to reflect the driver’s expectation on vehicle performance to a reasonable extent. For the purpose of ensuring the comprehensive performance and improving the individual-ability (i.e., the ability to adapt to different driver’s performance expectation) of vehicles equipped with SAT, a linear weighted method has been proposed to construct a performance evaluation function, which applies different weights to represent driver’s expectation on performance by using these weights to multiply the normalized value of each sub-performance index.

The clutch-to-clutch gear-shift process of dual clutch transmission (DCT), which consists of the overlapping of the engagement of the incoming clutch and the disengagement of the outgoing clutch, is a vital stage for the shift quality improvement. The paper investigated an integrated control strategy for the gear-shift process that takes into account the influences of oil pressure of dual clutches and engine speed on shift quality. Firstly, the evaluation indices for the shift quality of DCT were summarized, and the factors affecting the shift quality were analyzed. Secondly, an integrated control strategy for dual clutches pressure and engine speed was proposed. Through analyzing the states of clutch in the gear-shift process and the desired traction torque for different gears, the strategies of variable oil pressure and invariable oil pressure were determined for every gear-shift process.