Vehicle Transmission Control for Spontaneous Shifting
Solution Overview
Problem
Existing methods for operating vehicle transmission devices lack spontaneity in adjusting to a driver's desired operating state, particularly during manual shifting modes, as they do not adapt well to varying vehicle operating conditions, leading to inefficient gear changes and reduced tractive force.
Innovation Solution
A method that automatically changes transmission ratios based on current vehicle operating parameters compared to stored parameters, allowing manual adjustments by the driver, with features like earlier downshifts during braking and varying delay times based on deceleration and braking pressure to enhance spontaneity and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple sequential actuations of the selector lever are required to engage the required transmission ratio, then the transmission device can be controlled precisely, but the ease of operation deteriorates due to the need for multiple actions
Solution Approach 1:
The control unit stores the driver's shifting requests in a buffer and processes multiple requests simultaneously. When the driver actuates the selector lever multiple times, each request is stored and then executed in sequence without requiring the driver to wait for each individual shift to complete, effectively performing preliminary storage of actions to reduce perceived delay
Solution Approach 2:
The system uses a timer to manage periodic processing of buffered shifting requests. After a predetermined time period, the control unit checks for stored requests and executes them in sequence, creating a periodic action cycle that balances rapid response with controlled execution of multiple shifts
2Adaptability or versatility
If cyclical additional upshifts or downshifts are requested after a delay to improve spontaneity, then the adaptability improves, but the ease of operation deteriorates due to independent performance from operating state
Solution Approach 1:
The system dynamically adjusts the delay period and timing of cyclical shifts based on real-time operating state parameters such as vehicle speed, acceleration, and driver input patterns. The control unit monitors current operating conditions and modifies the timing characteristics of additional shifts to match the dynamic driving situation, making the system both spontaneous and context-appropriate
3Power
If downshifting occurs at higher vehicle speeds during braking to exploit braking effect, then the power improves for deceleration, but the reliability deteriorates due to potential engine damage from excessive speed
Solution Approach 1:
The control unit performs preliminary checks of engine speed and transmission ratio before executing downshifts during braking. The system evaluates whether a downshift would cause the engine speed to exceed safe limits and prevents the downshift if it would damage the engine, while still allowing downshifts that provide beneficial braking effect within safe operating parameters
Solution Approach 2:
The system continuously monitors engine speed, transmission ratio, and braking force as feedback parameters. Based on this real-time feedback, the control unit dynamically adjusts the downshifting strategy, allowing downshifts that enhance braking effect while automatically preventing shifts that would push engine speed beyond safe operating limits, thus balancing power and reliability
Data Source
AI summary
A method for operating a transmission of a vehicle drivetrain. A transmission ratio can be automatically changed during an operating state depending on a comparison of current operating state parameters with operating parameters stored in a control unit, and can be manually changed depending on a driver's request. Accordingly when the driver requests a change of the transmission ratio, the transmission ratio changes, and a timer starts. If the driver continues the ratio change from an actual transmission ratio value toward a larger or smaller transmission ratio value, the current operating parameters are compared with the stored operating parameters. Upon this comparison, the transmission shifts to higher ratios in comparison to the operating parameters stored in a control device at higher vehicle speeds, and/or a delay between sequential, cyclical transmission ratio changes varies depending on a vehicle deceleration and/or braking pressure in the region of a vehicle brake.