Automatic Transmission Shift Control Using Transverse Acceleration Compensation
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Solution Overview
Problem
Existing methods for raising shift-down points in automatic transmissions during vehicle deceleration fail to adequately account for transverse acceleration, leading to inconsistent shifting behavior when braking in bends, which can be disruptive, especially in dynamic driving styles.
Innovation Solution
A method that detects vehicle deceleration and cornering values to determine a compensated shift-down point, calculating a total force using deceleration and transverse acceleration, and selecting gears based on this compensated point to ensure timely shifting into lower gears during bends, even with reduced deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If shift-down points are raised as a function of deceleration only, then torque utilization is improved, but shifting behavior becomes inconsistent during cornering
Solution Approach 1:
The patent modifies the shift-down point calculation by introducing a compensation factor that changes based on transverse acceleration parameters. The compensated shift-down point is calculated as: compensated_shift_down_point = base_shift_down_point + compensation_factor * transverse_acceleration. This parameter change allows the system to adapt shift points to cornering conditions while maintaining torque utilization benefits.
Solution Approach 2:
The patent introduces a compensation factor as an intermediary element that mediates between the base shift-down point (determined by deceleration) and the actual shift-down point during cornering. This intermediary accounts for transverse acceleration effects and adjusts the shift point accordingly, ensuring consistent shifting behavior across different driving scenarios.
2Speed
If shift-down points are raised during braking, then dynamic driving capability is improved, but shifting performance deteriorates in bends
Solution Approach 1:
The system dynamically changes the shift-down point parameter based on transverse acceleration magnitude. During cornering, the compensation factor adjusts the shift-down point to account for reduced available deceleration, maintaining optimal shifting performance. The adjustment ensures that shifts occur at appropriate rotational speeds even when braking in bends, preserving dynamic driving capability.
3Use of energy by moving object
If deceleration-based shift control is used, then torque utilization is optimized, but cornering forces are not compensated
Solution Approach 1:
The patent creates a universal shift control mechanism that handles both straight-line braking and cornering scenarios through a single compensated shift-down point calculation. The system multiplies the compensation factor by transverse acceleration to generate an adjustment that works across different driving conditions, making the control strategy adaptable to various situations while maintaining optimized torque utilization.
Data Source
AI summary
A method for controlling an automatic transmission of a vehicle includes detecting a deceleration of the vehicle; detecting a cornering value of the vehicle; determining, as a function of the deceleration and as a function of the cornering value, a compensated shift-down point of a rotational speed at which shifting into a relatively low gear of the transmission occurs; and selecting a gear as a function of the compensated shift-down point.