Downhill Vehicle Speed Control by Predicting Auxiliary Brake Demand
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Solution Overview
Problem
In downhill slopes, the braking power of auxiliary brakes in motor vehicles is often insufficient to maintain vehicle speed below a desired level, leading to increased energy consumption and safety risks due to manual braking, which can cause wheel brake overheating and wear.
Innovation Solution
A method and apparatus that retrieve road gradient data and simulate the required braking power to prevent vehicle speed increase, determining the available braking power of auxiliary brakes and controlling vehicle speed or brake actuators to maintain the speed below the desired level, thereby avoiding manual braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If auxiliary brakes are used to control vehicle speed in downhill slopes, then automatic speed control is maintained, but the braking power is insufficient to prevent vehicle speed from increasing above the desired level
Solution Approach 1:
The control system performs preliminary simulation of required braking power based on road gradient data before entering the downhill slope. It determines in advance whether the auxiliary brakes will be sufficient and takes preventive action by controlling the vehicle speed before the downhill section to ensure the auxiliary brakes can maintain the desired speed level throughout the descent.
Solution Approach 2:
The system uses feedback from road gradient data retrieval and simulated braking power requirements to dynamically adjust the vehicle speed control strategy. The control unit continuously monitors whether the available auxiliary braking power is sufficient and adjusts the vehicle speed accordingly to maintain reliable automatic control throughout the downhill slope.
2Reliability
If manual braking is used when auxiliary brakes are insufficient, then vehicle speed can be controlled, but energy consumption increases and wheel brakes may overheat
Solution Approach 1:
The system determines in advance whether manual braking will be needed by simulating the required braking power before entering the downhill slope. If insufficient auxiliary braking power is predicted, the control unit proactively reduces vehicle speed before the downhill section to ensure auxiliary brakes alone can maintain control, thereby preventing the need for energy-consuming manual braking during the descent.
3Speed
If manual braking is used to control vehicle speed, then speed can be reduced, but wheel brake overheating and wear increase
Solution Approach 1:
The control system performs preliminary assessment of auxiliary braking sufficiency before entering the downhill slope. When insufficient braking power is predicted, it proactively controls vehicle speed before the downhill section to ensure the auxiliary brakes can maintain the desired speed level throughout the descent, thereby preventing manual wheel brake usage and avoiding overheating and wear.
Solution Approach 2:
The system converts the potential harm of insufficient auxiliary braking power into a beneficial preventive action by detecting the insufficiency in advance and adjusting vehicle speed before the downhill section. This transforms what would have been a harmful situation requiring manual braking into a controlled scenario where auxiliary brakes suffice, eliminating wheel brake overheating and wear.
Data Source
AI summary
A method for controlling a motor vehicle, comprising: retrieving road gradient data relating to an expected travelling route of the motor vehicle; based on at least the retrieved road gradient data and on a motor vehicle mass, simulating a required value of a braking power related variable, which required value is needed to prevent a vehicle speed from increasing above a preset desired vehicle speed in an upcoming downhill slope; determining an available value of the braking power related variable of at least one auxiliary brake of the motor vehicle; and based on the determined available value and the simulated required value of the braking power related variable, controlling the vehicle speed and/or at least one brake actuator of the motor vehicle such that the vehicle speed does not increase above the preset desired vehicle speed in the upcoming downhill slope.