Transmission Downshift Control for Auxiliary Brake Faults on Downgrades
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Solution Overview
Problem
Existing vehicle control systems struggle to effectively manage transmission settings and auxiliary brake systems when an auxiliary brake failure occurs, particularly on negative road grades where additional braking is needed.
Innovation Solution
A controller system that monitors the operation of the auxiliary brake system, detects faults, and adjusts transmission settings by downshifting at least two gears to compensate for the loss of auxiliary braking, especially when descending a negative road grade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the auxiliary brake system is used to slow the vehicle, then the braking effectiveness is improved, but the system reliability deteriorates when a fault occurs
Solution Approach 1:
The controller performs preliminary detection of auxiliary brake faults and proactively compensates by downshifting the transmission before the fault fully manifests its braking deficiency. This advance action prevents the vehicle from entering a dangerous state where braking is insufficient.
Solution Approach 2:
The system changes the transmission gear ratio parameter by downshifting at least two settings when auxiliary brake fault is detected. This parameter change compensates for the loss of auxiliary braking force, maintaining overall braking effectiveness despite the reliability issue.
2Device complexity
If the transmission downshifts only one setting to compensate for auxiliary brake failure, then the device complexity is minimized, but the braking performance is insufficient on negative road grades
Solution Approach 1:
The system applies excessive action by downshifting at least two transmission settings instead of the minimal one setting. This ensures sufficient braking performance on negative road grades where a single downshift would be inadequate, while still maintaining relatively simple control logic.
3Ease of operation
If the vehicle maintains current transmission setting during auxiliary brake fault, then the ease of operation is maximized, but the vehicle speed control deteriorates on downhill slopes
Solution Approach 1:
The controller continuously monitors auxiliary brake system status and provides feedback control by automatically downshifting the transmission when a fault is detected. This closed-loop feedback ensures proper speed control on downhill slopes without requiring driver intervention, balancing operational simplicity with effective speed management.
Data Source
AI summary
Systems, apparatuses, and methods for controlling a transmission and other vehicle systems and components based on operation of an auxiliary braking system for a vehicle are disclosed. A controller for a vehicle includes a processing circuit having at least one memory device coupled to at least one processor, the at least one memory device is configured to store instructions thereon that, when executed by the at least one processors, cause the at least one processor to: receive data regarding operation of an auxiliary brake system of the vehicle; determine an auxiliary brake fault condition based on the received data regarding operation of the auxiliary brake system; determine that the vehicle is on or is about to experience a negative road grade; determine a vehicle speed is greater than a requested vehicle speed for the negative road grade; and control a transmission to downshift at least two settings relative to a current transmission setting.