Vehicle Drive Control Device Torque Limiting for Downshift Shock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle drive device control systems experience two-stage acceleration shocks during power-on downshifts, leading to discomfort for drivers and potential worsening of initial responsivity due to delayed torque rise in automatic transmissions.
Innovation Solution
A control device that limits input torque to the automatic shifting portion before the initiation of the inertia phase during downshifts, adjusting the torque limit based on accelerator variation, ensuring sufficient initial response and alleviating two-stage acceleration shocks by varying the input torque according to the accelerator operation speed or amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If input torque is uniformly limited upon power-on downshift, then two-stage acceleration shocks are alleviated, but initial responsivity worsens due to delay in output torque rise
Solution Approach 1:
The patent applies dynamics by making the torque limit value adjustable rather than fixed. The control device dynamically changes the torque limit value based on accelerator operation amount: using a first torque limit value when accelerator operation is small and a second torque limit value when accelerator operation is large. This dynamic adjustment resolves the contradiction by adapting the torque limitation to actual driving conditions, thereby alleviating acceleration shocks while preserving initial responsivity.
Solution Approach 2:
The patent implements parameter changes by varying the torque limit value parameter based on accelerator operation amount. When the accelerator operation amount exceeds a threshold, the system switches from the first torque limit value to the second torque limit value. This parameter change strategy allows the system to optimize both shock alleviation and initial responsivity by selecting appropriate torque limit values according to the driver's acceleration demand.
2Object-affected harmful factors
If input torque is limited before inertia phase, then two-stage acceleration shocks are suppressed, but drive force response becomes delayed
Solution Approach 1:
The patent resolves this contradiction through parameter changes by implementing two different torque limit values. The first torque limit value is applied when accelerator operation is small, providing sufficient limitation to suppress acceleration shocks. The second torque limit value is applied when accelerator operation is large, reducing the limitation effect to ensure prompt torque rise and minimize time loss. This conditional parameter adjustment optimizes both shock suppression and torque response timing.
Solution Approach 2:
The system dynamically adjusts the torque limitation strategy based on real-time accelerator operation detection. By monitoring the accelerator operation amount and switching between different torque limit values, the system achieves dynamic optimization that suppresses acceleration shocks under normal conditions while ensuring rapid torque delivery when the driver demands strong acceleration.
3Power
If throttle position is opened to increase engine torque, then drive force increases, but two-stage acceleration shocks occur during downshift
Solution Approach 1:
The patent applies preliminary anti-action by preemptively limiting the engine torque through throttle control when a downshift is detected. The control device identifies downshift conditions and applies appropriate torque limit values before the downshift completes, preventing the clutch torque capacity drop from causing acceleration shocks. This preliminary intervention maintains engine torque within safe limits while avoiding the harmful two-stage shock effect.
Solution Approach 2:
The system uses feedback by continuously monitoring accelerator operation amount and adjusting the torque limit value accordingly. When the accelerator operation indicates a downshift scenario, the feedback mechanism triggers the application of torque limit values to prevent acceleration shocks, while still allowing sufficient torque delivery to maintain drivability and initial responsivity.
Data Source
AI summary
A control device limiting an input torque to an automatic shifting portion before initiation of an inertia phase in a downshift as compared to a case of not executing the downshift, wherein in an input torque limiting control, if an accelerator variation before a start of the downshift is equal to or less than a predetermined accelerator variation limit, the control device limits the input torque before the initiation of the inertia phase to the input torque at a time of a shifting output commanding the execution of the downshift, and wherein if an accelerator variation before the start of the downshift is greater than the accelerator variation limit, the control device limits the input torque before the initiation of the inertia phase equal to or less than a predetermined input torque limit value larger than the input torque at the time of the shifting output.