Vehicle Torque Control Apparatus Tip-In Shock Prevention
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Solution Overview
Problem
Existing vehicle control systems fail to effectively restrict or prevent 'tip-in shock' and ensure high drivability when the accelerator pedal is operated in a non-driven state, particularly due to inadequate engine torque limiting control during transitions in vehicle speed and transmission gear ratios.
Innovation Solution
A control apparatus that determines the vehicle's state by adjusting a torque threshold value based on running speed and transmission speed ratio, implementing engine torque limiting control when the vehicle is likely to experience tip-in shock and allowing increased acceleration response when it is unlikely, using sensors to detect accelerator pedal operation and setting threshold values to optimize engine torque management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If engine torque limiting control is implemented based on a fixed threshold value, then tip-in shock is restricted or prevented, but acceleration response deteriorates when torque limiting is applied inappropriately
Solution Approach 1:
The patent applies dynamics by making the torque threshold value variable rather than fixed. The threshold is dynamically adjusted based on vehicle running speed and transmission speed ratio, allowing the control system to adapt to different operating conditions. This resolves the contradiction by enabling torque limiting only when actually needed (preventing tip-in shock) while allowing full acceleration response when the vehicle is already in a driven state or at low speeds where tip-in shock is unlikely.
Solution Approach 2:
The patent changes the parameter of torque threshold value from a constant to a variable that depends on vehicle running speed and transmission speed ratio. By establishing a relationship where the threshold increases with vehicle speed and speed ratio, the system accurately determines non-driven states and applies torque limiting control only when appropriate, thus preventing tip-in shock without unnecessarily restricting acceleration response.
2Object-affected harmful factors
If torque limiting control is applied in all non-driven states, then tip-in shock is prevented, but drivability deteriorates due to unnecessary torque restriction
Solution Approach 1:
The patent changes the torque threshold parameter based on vehicle operating conditions (speed and speed ratio). This allows the system to distinguish between actual non-driven states requiring torque limiting and driven states where torque limiting would be unnecessary. By using variable thresholds, the system maintains good drivability while effectively preventing tip-in shock.
Solution Approach 2:
The patent uses feedback from vehicle speed sensors and transmission speed ratio sensors to continuously monitor vehicle state and adjust the torque threshold accordingly. This feedback mechanism ensures torque limiting control is applied only when the vehicle is truly in a non-driven state, preventing tip-in shock without degrading drivability during normal operation.
3Speed
If the threshold value is increased to prevent unnecessary torque limiting, then acceleration response is improved, but tip-in shock cannot be prevented when the threshold is too high
Solution Approach 1:
The patent establishes a functional relationship where the torque threshold value changes based on vehicle running speed and transmission speed ratio. The threshold is set to increase with both speed and speed ratio, which accurately reflects the conditions under which tip-in shock occurs. This dynamic parameter adjustment ensures the threshold is high enough to prevent unnecessary torque limiting (maintaining acceleration response) but low enough to prevent tip-in shock when appropriate.
Data Source
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AI summary
A control apparatus (60) for a vehicle (10) including an engine (12), and an automatic transmission (26) to transmit a drive force of the engine to drive wheels (14), the control apparatus including a vehicle state determining portion (66) configured to determine whether the vehicle is placed in a non-driven state or not, and an engine control portion (62) configured to implement an engine torque limiting control to restrict an increase of a torque of the engine in response to an increase of an operation amount (pap) of a vehicle accelerating member, the control apparatus further including a threshold setting portion (60 configured to set a threshold value (Teth*) of a torque (Te) of the engine such that the threshold value increases with an increase of a running speed (V) of the vehicle and/or a speed ratio (γ) of the automatic transmission, and wherein the vehicle state determining portion (66) determines that the vehicle is placed in the non-driven state when the torque of the engine upon the increase of the operation amount of the vehicle accelerating member is smaller than the threshold value.