Vehicular Power Transmission Jump Shift Control
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Solution Overview
Problem
Existing control apparatuses for vehicular power transmitting systems fail to ensure a high degree of control response for jump shift-down actions in automatic transmissions, particularly when the engine speed is below a predetermined lower limit, leading to inhibited shift-down actions and sequential shift-down operations.
Innovation Solution
A control apparatus that determines whether a jump shift-down action should occur and compares the total sequential-shift-down-operation time with the total jump-shift-down-action time, generating a shifting command to perform the jump shift-down action if it is shorter, ensuring a higher control response by selecting the operation completed at an earlier time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a jump shift-down action is inhibited when engine speed is below a predetermined lower limit, then the operating speed of the first electric motor is prevented from excessively rising, but the control response of the automatic transmission portion is degraded
Solution Approach 1:
The control apparatus dynamically adjusts the shifting strategy by comparing the time required for jump shift-down action with the time required for sequential shift-down operation. When the jump shift-down can be completed faster than sequential operation, the inhibition is lifted and jump shift-down is permitted, even when engine speed is below the lower limit. This dynamic time-based comparison allows the system to optimize between preventing excessive motor speed rise and maintaining fast control response.
Solution Approach 2:
The control apparatus changes the decision parameter from a static engine speed threshold to a dynamic time comparison. Instead of solely relying on engine speed being above a predetermined lower limit, the system now considers the relative timing of jump shift-down versus sequential shift-down operations. This parameter change enables the system to permit jump shift-down actions under specific time conditions, thereby improving control response while still managing electric motor speed rise through the time-based assessment.
2Reliability
If sequential shift-down operation is performed instead of jump shift-down action, then the electric motor speed rise is controlled, but the total shifting time is increased
Solution Approach 1:
The control apparatus dynamically selects between jump shift-down action and sequential shift-down operation based on a time comparison. When the jump shift-down can be completed in less time than sequential operation, the system chooses jump shift-down, accepting the electric motor speed rise. When sequential operation is faster, the system chooses sequential operation to control electric motor speed. This dynamic selection optimizes the trade-off between time loss and electric motor speed control.
Solution Approach 2:
The control apparatus changes the decision criterion from fixed engine speed thresholds to a flexible time-based comparison. By evaluating whether jump shift-down time is shorter than sequential shift-down time, the system adapts its shifting strategy to current operating conditions. This parameter change allows the system to minimize total shifting time when jump shift-down is feasible, while still controlling electric motor speed rise when sequential operation is more efficient.
Data Source
AI summary
A control apparatus for a vehicular power transmitting system including an electrically controlled differential portion having an electric motor, and an automatic transmission portion, the control apparatus including shift control portion operable upon determination that a jump shift-down action of the automatic transmission portion directly to a target gear position while skipping at least one intermediate gear position should take place and upon inhibition of the jump shift-down action, to generate a shifting command to perform the jump shift-down action when total jump-shift-down-action time required for the jump shift-down action is shorter than total sequential-shift-down-operation time required for a sequential shift-down operation consisting of a shift-down action to each intermediate gear position and a shift-down action from the last intermediate gear position to the target gear position, and a shifting command to perform the sequential shift-down operation when the total jump-shift-down-action time is not shorter than the total sequential-shift-down-operation time.