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Selection of gearshift point plays an important role in the field of automatic transmission technology, which directly affects the vehicle dynamic and economic performance, etc. In order to designing optimal gearshift strategies for conventional passenger vehicles equipped with stepped automatic transmission, in this paper, the vehicle power demand was defined under different environment, different driving intention and different vehicle operating conditions. Dynamic programming (DP) method is used to solve the optimal static gearshift decision sequence based on the simplified model of powertrain system. The drivability is respected by imposing an inequality constraint on the power reserve limit and the fuel economy is the objective function. Considering the change of vehicle additional load and road slope, the gearshift strategy based on power reserve is proposed.

In order to solve the problem of frequent shifting for heavy-duty commercial vehicle Equipped with Automatic Manual Transmission (AMT), AMT override shift control strategy for heavy-duty commercial vehicles based on power demand was proposed. Power demand was calculated based on parameters such as engine speed, torque, speed, load, and travel ramp. Under the premise of satisfying the dynamic nature, with the goal of fuel economy, the target gear was determined. The shift strategy has been applied to the development of Beiqi Futian AMT prototype vehicle. The results showed that: this strategy can achieve more than 1 gear upshift and more than a multi-gear downshift, the frequency of shifts was reduced.