Vehicle Transmission Shift Threshold Control for Smooth Acceleration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-stage transmission systems, such as automatic and automated manual transmissions, experience torque interruption during acceleration, leading to drivability and comfort issues due to sudden shifts, which current technologies fail to prevent effectively.
Innovation Solution
A transmission control device that dynamically adjusts the shift map threshold based on vehicle state and operation plans to prevent shift-ups during acceleration, thereby minimizing torque interruption shocks by delaying gear shifts until the accelerator is loosened.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If shift-up is performed during acceleration in multi-stage transmission, then gear ratio is optimized for speed, but torque interruption occurs causing drivability and comfort degradation
Solution Approach 1:
The shift map threshold is made dynamic rather than fixed. The ECU adjusts the shift determination threshold based on accelerator depression amount and vehicle state, allowing the shift-up condition to change dynamically. This enables the system to prevent shift-up during acceleration when accelerator depression is large, while allowing shift-up under other conditions, thus resolving the contradiction between speed optimization and drivability reliability.
Solution Approach 2:
The invention changes the parameter of shift determination threshold in the shift map. By adjusting this threshold parameter based on accelerator depression amount and vehicle state, the system prevents shift-up during acceleration phases while maintaining normal shift operations elsewhere, thereby eliminating torque interruption shocks and improving drivability without permanently sacrificing speed optimization capabilities.
2Object-affected harmful factors
If throttle is loosened to mitigate torque interruption shock, then rider comfort improves, but acceleration time increases
Solution Approach 1:
The system performs preliminary assessment of vehicle state and accelerator depression amount before shift-up occurs. By predicting when shift-up would cause torque interruption shock and preventing it in advance through dynamic threshold adjustment, the system eliminates the need for reactive throttle loosening operations, thus avoiding the time loss that would result from such corrective actions.
Solution Approach 2:
The dynamic shift threshold acts as an intermediary mechanism between the driver's acceleration demand and the transmission's shift operation. Instead of directly loosening the throttle to mitigate shock, the system uses the adjustable shift threshold to indirectly prevent torque interruption, thereby maintaining acceleration performance while still protecting rider comfort.
3Device complexity
If shift map threshold is fixed, then control simplicity is maintained, but torque interruption cannot be prevented during acceleration
Solution Approach 1:
The shift map threshold transitions from a fixed value to a dynamic value that changes based on vehicle state and accelerator depression amount. This dynamic adjustment mechanism, implemented through ECU processing of sensor inputs, provides torque interruption prevention capability while maintaining relatively simple system architecture, thus resolving the contradiction between control simplicity and reliability.
Data Source
Figure 1
Figure 2~3
Figure 4
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 50 so as not to perform the shift-up of the transmission 50 during acceleration of the vehicle 1.