Vehicle Transmission Shift Map Control to Prevent Torque Interruption
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Solution Overview
Problem
Existing transmission control systems for vehicles with multi-stage transmissions experience torque interruption during acceleration, leading to drivability issues and discomfort due to sudden torque changes, which current technologies fail to prevent effectively.
Innovation Solution
A transmission control device with a shift threshold setting unit that adjusts the shift map based on the vehicle's operation plan and surrounding state to prevent shift-ups during acceleration, using a predicted upper limit vehicle speed and relative speed to determine optimal shift timing, thereby minimizing torque interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If shift-up is performed during acceleration to improve transmission efficiency, then power transmission is improved, but torque interruption shock occurs deteriorating drivability and riding comfort
Solution Approach 1:
The system performs preliminary detection of acceleration states before shift-up occurs. When acceleration is detected, the control unit preemptively adjusts shift timing or suppresses shift-up, preventing torque interruption shock before it occurs. This is achieved by monitoring accelerator depression amount and vehicle speed to identify acceleration phases, then modifying shift control accordingly.
2Object-affected harmful factors
If throttle is loosened before shift-up to reduce torque interruption shock, then riding comfort is improved, but acceleration time increases
Solution Approach 1:
The invention extracts the harmful element (throttle loosening action) from the shift control process. Instead of loosening the throttle before shift-up, the system directly controls shift timing based on detected acceleration states. This removes the unnecessary intermediate action that caused delayed acceleration, allowing the vehicle to maintain full throttle while preventing torque interruption shock through intelligent shift timing control.
3Reliability
If shift threshold is lowered to prevent shift-up during acceleration, then torque interruption is prevented, but transmission efficiency decreases
Solution Approach 1:
The system dynamically adjusts shift thresholds based on real-time driving conditions rather than using fixed thresholds. During detected acceleration phases, the shift threshold is temporarily raised to prevent shift-up. During normal cruising or deceleration, the threshold returns to standard values for optimal efficiency. This dynamic adaptation allows the system to prevent torque interruption only when necessary, maintaining high transmission efficiency in other operating conditions.
Data Source
AI summary
The present invention provides a transmission control device for a vehicle capable of changing a threshold of a shift map for determining shift-up, thereby preventing occurrence of the shift-up during depression of an accelerator and preventing occurrence of a torque interruption. In a transmission control device for a vehicle 1 including a T/M-ECU 50 which automatically performs shift control for switching a plurality of shift gears of a transmission 20 for shift-up or shift-down, the T/M-ECU 50 has a shift threshold setting unit 54 which sets a shift threshold to be used for the shift control, on the basis of an operation plan or a surrounding state of the vehicle 1, and the shift threshold setting unit 54 sets the shift threshold to perform the shift control on the transmission 20 so as not to perform the shift-up of the transmission 20 during acceleration of the vehicle 1.