Automatic Downhill Speed Control for Vehicle Grade Energy Absorption
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Solution Overview
Problem
Vehicle operators must manually adjust throttle and/or apply brakes to maintain constant speed while traveling downhill, which is inconvenient and requires continuous attention.
Innovation Solution
An automatic downhill speed control system that absorbs grade-induced energy by comparing the current vehicle speed with a target speed using a feedback controller, triggering retarding or regenerating devices when the throttle is released and specific conditions are met, such as a minimum speed and deactivation of anti-lock brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual throttle adjustment and brake application are used to maintain constant vehicle speed downhill, then vehicle speed control is achieved, but operator attention and continuous manual intervention are required
Solution Approach 1:
The system enables self-service by automatically detecting downhill conditions through sensor inputs (throttle position, vehicle speed, brake status) and autonomously activating retarding devices without requiring operator attention or manual intervention
Solution Approach 2:
The control module continuously receives feedback from sensors monitoring throttle position, vehicle speed, and brake pedal status, using this information to dynamically adjust retarding device activation and maintain desired vehicle speed downhill
2Use of energy by moving object
If retarding and regenerating devices are activated to absorb grade-induced energy, then fuel efficiency is improved, but system complexity increases
Solution Approach 1:
The control module serves multiple functions by integrating detection of downhill conditions, determination of appropriate retarding strategies, and coordination of both retarding and regenerative devices within a single control unit, reducing overall system complexity despite multiple components
Solution Approach 2:
The system merges retarding device control and regenerative device control into a unified control strategy, where the control module coordinates both device types to absorb grade-induced energy, maximizing fuel efficiency while managing system complexity through integrated control
3Extent of automation
If automatic downhill speed control is implemented, then operator attention is reduced, but additional control conditions and safety checks are required
Solution Approach 1:
The control module performs preliminary checks of multiple conditions (throttle position, vehicle speed, brake status, anti-lock brake state) before activating automatic downhill speed control, ensuring safety and appropriateness before autonomous operation begins
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Automatically maintains vehicle speed while traveling downhill, reducing the need for operator intervention and improving fuel efficiency by using regenerative energy storage in hybrid vehicles.
Implementation Method 1
A feedback controller compares a predefined vehicle target speed with a current vehicle speed to generate an error signal... to absorb the grade-induced energy
Data Source
AI summary
The present invention provides a method for automatic downhill speed control or ADSC adapted to automatically absorb grade-induced energy so that the vehicle operator is no longer required to take action to maintain generally constant vehicle speed. ADSC is preferably triggered if the throttle is released and the vehicle accelerates. The specific amount of throttle release necessary to trigger ADSC is variable but may, according to a preferred embodiment, be set at 85% throttle reduction. According to another preferred embodiment, ADSC is not triggered unless the throttle is released for a predetermined amount of time such as, for example, 5 seconds.