Vehicle Shifting Delay Control for Step-Variable Transmission
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Solution Overview
Problem
The existing control apparatuses for vehicles with step-variable transmissions face challenges in reducing shifting shocks during shift-down actions, especially when the battery charging amount is limited, as the regenerative control of the second electric motor is insufficient to absorb excess output, leading to potential shifting shocks.
Innovation Solution
A control apparatus that delays the generation of the shift-down command to implement a power-on shift-down action, adjusting the delay time based on the output state of the drive power source, inertia power, consumption power, and battery state to stabilize the output and reduce shifting shocks, while also considering the risk of deterioration in shifting control response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regenerative control of the second electric motor is used to absorb excess output during shift-down action, then the rate of rise of input shaft speed is restricted and shifting shock is reduced, but when battery charging amount is limited, the excess output cannot be sufficiently absorbed and shifting shock still occurs
Solution Approach 1:
The control apparatus delays the generation of the shift-down command relative to the determination moment. By postponing the shift-down command generation timing, the excess output from the drive power source during the inertia phase is reduced, allowing sufficient absorption by the regenerative control of the second electric motor even when battery charging capacity is limited, thereby preventing shifting shock
2Reliability
If the shift-down command is delayed to reduce shifting shock, then the excess output is better absorbed by regenerative control, but the shifting control response may deteriorate
Solution Approach 1:
The control apparatus dynamically adjusts the delay time based on multiple parameters including the output state of the drive power source, inertia power required during shift-down, consumption power of coupling devices, and battery state. This dynamic adjustment optimizes the balance between reducing shifting shock and maintaining acceptable shifting control response under different operating conditions
3Device complexity
If a fixed delay time is used, then the control is simple, but it cannot adapt to different operating conditions and may cause either excessive delay or insufficient shock reduction
Solution Approach 1:
The control apparatus changes the delay time parameter based on the actual operating conditions, including drive power source output state, inertia power requirements, coupling device consumption power, and battery state. This allows the system to adapt to different operating conditions and optimize shifting shock reduction effectiveness
Data Source
AI summary
A control apparatus includes a shifting delay control portion configured to delay a moment of generation of a shift-down command to implement a power-on shift-down action of the step-variable transmission, with respect to a moment of determination to implement the power-on shift-down action, for thereby reducing a shifting shock of the step-variable transmission in the process of the power-on shift-down action. The shifting delay control portion adjusts a delay time from the moment of determination to implement the power-on shift-down action to the moment of generation of the shift-down command, on the basis of at least one of an output state of the drive power source; an inertia power required in the process of the power-on shift-down action; a consumption power to be consumed by the coupling devices; and a state of a battery to and from which an electric power is respectively supplied from and to the motor/generator.