Lockup Clutch Control Using Predicted Attainment Time
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Solution Overview
Problem
Existing control systems for vehicles with torque converters and lockup clutches fail to optimally engage and disengage the lockup clutch during automated driving, leading to delays in increasing driving force when needed, especially on uphill roads.
Innovation Solution
A control device that includes an automated drive control unit, a predicted attainment period calculating unit, and a first engaging and disengaging control unit to calculate the time required to reach target inter-vehicle distance or speed and switch the lockup clutch accordingly, ensuring optimal control during automated driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the lockup clutch is kept in the engaged state to suppress vehicle speed variance during automated driving, then ride comfort is improved, but driving force becomes insufficient when needed (e.g., on uphill roads)
Solution Approach 1:
The lockup clutch control system transitions from a static engaged/disengaged state to a dynamic controlled slip state. The slip control unit allows the lockup clutch to operate in a slip state where the input shaft and output shaft rotate at different speeds, enabling continuous adjustment of torque transmission. This dynamic operation allows the system to maintain engine-driven torque amplification through the torque converter while still providing sufficient driving force when needed.
Solution Approach 2:
The system changes the operational parameters of the lockup clutch by introducing controlled slip between the input and output shafts. Instead of maintaining a fixed engaged state, the control unit adjusts the slip amount based on driving conditions, thereby changing the torque transmission characteristics. This parameter change enables the system to optimize both vehicle speed stability and driving force availability.
2Power
If the lockup clutch is switched to the disengaged state to increase driving force through torque amplification, then driving force is improved, but vehicle speed variance increases and ride comfort deteriorates
Solution Approach 1:
The system uses dynamic slip control to gradually adjust torque transmission rather than making abrupt transitions between engaged and disengaged states. The slip control unit modulates the slip amount to smoothly transition torque levels, maintaining vehicle speed stability while providing increased driving force when needed.
Solution Approach 2:
The control unit continuously monitors vehicle operating conditions and adjusts the lockup clutch slip amount in real-time based on feedback. This closed-loop control ensures that vehicle speed stability is maintained while providing sufficient driving force, as the system responds to actual vehicle performance rather than pre-programmed conditions.
3Device complexity
If conventional engaging and disengaging control based on accelerator operation amount and present vehicle speed is used, then control simplicity is maintained, but response delay occurs when switching to disengaged state is needed
Solution Approach 1:
The system performs preliminary assessment of driving conditions by the predicted attainment period calculation unit, which evaluates whether the vehicle can reach the target state within the available time. This preliminary calculation allows the control unit to proactively adjust the lockup clutch state before driving force becomes critically insufficient, reducing response delay while maintaining control simplicity.
Solution Approach 2:
The system replaces conventional mechanical control based solely on accelerator position and vehicle speed with an intelligent control system that incorporates predicted attainment period calculations. This substitution enables faster, more accurate decision-making about lockup clutch state transitions while maintaining overall system simplicity through algorithmic rather than mechanical complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for immediate adjustment of the lockup clutch state to enhance driving force when necessary, thereby optimizing vehicle performance and reducing delays during automated driving.
Implementation Method 1
increasing the driving force by torque amplification of the torque converter
Data Source
AI summary
The electronic control unit includes: an automated drive control unit that performs automated driving control; an predicted attainment period calculation unit that calculates an inter-vehicle distance or a predicted attainment period of the inter-vehicle distance or the vehicle speed until the inter-vehicle distance or the target vehicle speed is reached, when LU clutch is in an engaged state while the automated driving is in progress; and a first connection/disconnection control unit that performs control to switch LU clutch to the released state when the inter-vehicle distance or the vehicle speed is larger than a preset target attainment period, and to continue the engaged state of LU clutch when the inter-vehicle distance or the vehicle speed is equal to or smaller than the target attainment period.