Transmission Gearshift Control for Sustained Braking Load
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Solution Overview
Problem
Existing methods for controlling gearshifts in motor vehicle transmissions do not effectively adapt to the operation of sustained-action braking devices, leading to suboptimal integration and braking performance.
Innovation Solution
A method that checks the starting criterion for the sustained-action braking device's operation and adjusts the gearshift strategy by comparing the current workload with threshold values, allowing for direct gearshift to the lowest possible gear or adapting shifting characteristics based on the selected actuation level and service brake conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gearshift strategy is adapted based on sustained-action braking device operation, then the braking performance is optimized, but the control complexity increases
Solution Approach 1:
The control unit checks the starting criterion for sustained-action braking device operation in advance, before the actual braking occurs. This allows the gearshift strategy to be pre-adapted to the braking conditions, ensuring optimal braking performance without adding complex real-time control logic during braking execution.
Solution Approach 2:
The control unit continuously monitors the operation state of the sustained-action braking device and uses this feedback information to adapt the gearshift strategy. By comparing the current workload with threshold values, the system dynamically adjusts gearshift timing and characteristics to optimize braking performance while maintaining manageable control complexity through rule-based decision logic.
2Reliability
If the gearshift strategy is adapted by comparing workload with threshold values, then the braking performance is optimized, but the control logic becomes more complex
Solution Approach 1:
The control unit adapts the gearshift strategy by changing parameters such as gearshift timing, gear selection, and shifting characteristics based on the comparison between current workload and threshold values. This parameter-based adaptation allows optimization of braking performance through quantitative criteria without requiring complex control logic, as the decision-making is based on straightforward threshold comparisons.
3Force
If direct gearshift to the lowest possible gear is performed, then the braking torque transmission is maximized, but the transmission wear increases
Solution Approach 1:
The control unit applies different gearshift strategies to different operating conditions. When sustained-action braking is detected with workload exceeding threshold values, direct gearshift to the lowest possible gear is performed to maximize braking torque transmission. For other conditions, normal gearshift strategies are maintained, thereby avoiding unnecessary transmission wear while ensuring optimal braking performance when required.
Data Source
AI summary
A method is disclosed for controlling gearshifts in a transmission of a motor vehicle. Devising a shifting strategy of the gearshift takes into account the operation of a sustained-action braking device (10). To organize gearshifts in an optimum way having regard to the operation of the sustained-action braking device (10), at the beginning of the operation of the sustained-action braking device (10) it is examined with what starting criterion the operation of the sustained-action braking device (10) was initiated. Depending on the starting criterion identified, a current workload of the sustained-action braking device (10) is compared against an associated threshold value. Alternately, a gearshift is carried out directly to a lowest possible gear of the motor vehicle transmission (4). If the comparison of the current workload of the sustained-action braking device (10) exceeds the threshold value, then the shifting strategy is adapted.