Motor Vehicle Starting Aid Control via Rotational Direction Detection
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Solution Overview
Problem
Existing methods for controlling a motor vehicle's starting aid struggle to balance preventing roll-back on inclines with maintaining drive comfort and reliability, often resulting in increased fuel consumption and mechanical complexity.
Innovation Solution
A method that reduces braking pressure in a motor vehicle by detecting the rotational direction of the output shaft, using a predetermined gradient for initial release and adjusting based on detected signals to ensure safe roll-back prevention while enhancing comfort and reliability, with optional safety and comfort modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the braking pressure is reduced slowly to prevent roll-back on inclines, then the vehicle safety is improved, but the drive comfort deteriorates and fuel consumption increases
Solution Approach 1:
The braking pressure reduction is made dynamic by detecting the rotational direction of the output shaft. The system transitions from a static slow release (safe but uncomfortable) to a dynamic release that adapts to actual vehicle movement conditions, allowing fast release when safe and slow release when needed
Solution Approach 2:
The system uses feedback from the rotational direction detection of the output shaft to control the braking pressure reduction. The detection unit provides real-time information about vehicle movement, allowing the control unit to adjust the release rate accordingly - this closed-loop feedback resolves the contradiction by making safety dependent on actual conditions rather than predetermined fixed rates
2Adaptability or versatility
If a mechanical switch is used to detect switching mode changes on the brake, then the grade detection capability is improved, but the device complexity increases and reliability decreases
Solution Approach 1:
The mechanical switch on the brake is replaced with an electronic detection system that monitors the rotational direction of the output shaft. This substitution eliminates the mechanical switch and its associated complexity while maintaining the ability to detect grade conditions through electronic sensors and control units
Solution Approach 2:
The rotational direction detection system serves multiple functions: it detects grade conditions, determines vehicle movement state, and controls the braking pressure release. This multi-functional approach replaces the specialized mechanical switch with a more versatile electronic system that reduces overall device complexity
3Ease of manufacture
If the braking pressure is reduced according to a fixed gradient, then the control simplicity is improved, but the adaptability to different road grades deteriorates
Solution Approach 1:
The fixed gradient control is transformed into a dynamic control system that adjusts the braking pressure reduction based on detected rotational direction. The system maintains simplicity in implementation while adapting to different grades through real-time detection feedback rather than pre-programmed fixed gradients
Data Source
AI summary
The invention concerns a method for controlling a starting aid of a motor vehicle, in particular of a bus. The release of the starting aid takes place as follows: reduction of the braking pressure in accordance with a predetermined first gradient; simultaneous detection of the rotational direction of an output shaft of a transmission of the motor vehicle or of another component which rotates as a function of the rotational speed of the drive wheels; upon detection of a rotational-direction signal which indicates forward travel of the motor vehicle, continuation of the reduction in the braking pressure in accordance with the predetermined first gradient and upon detection of another signal, continuation of the reduction of the braking pressure by way of a second gradient which is reduced in comparison with the first gradient or an increase in the braking pressure.