Vehicle Control System for Engine Overspeed Prevention
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Solution Overview
Problem
Existing vehicle control systems with electronic gear shift and engine overspeed prevention modes limit a driver's ability to use engine braking when towing trailers downhill, as they prevent downshifting to lower transmission ratios to avoid engine damage, thereby reducing the effectiveness of engine braking.
Innovation Solution
A control system that allows the driver to apply brakes proportionally to the engine speed by converting downshift commands into braking force, using a hand-operable control element connected to a controller, which prevents downshifting when engine speed exceeds a threshold and applies braking force to the wheels, allowing for controlled engine speed management without separate brake pedal use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If downshifting is prevented when engine speed exceeds threshold, then engine damage is avoided, but driver's ability to use engine braking is limited
Solution Approach 1:
The control system acts as an intermediary between the driver's downshift command and the transmission system. When engine speed exceeds the threshold, the controller intercepts the downshift command and converts it into a brake application signal instead of executing the downshift, thereby protecting the engine while still providing the driver with a means to control vehicle speed
Solution Approach 2:
The system changes the functional parameter of the gearshift device based on engine speed conditions. Normally the gearshift device controls transmission ratio, but when engine speed exceeds the threshold, its function is dynamically changed to control brake application, allowing the same interface to serve dual purposes under different operating conditions
2Productivity
If downshift command is converted to brake application, then vehicle speed control is improved, but driver interface complexity increases
Solution Approach 1:
The gearshift device is designed with multi-functionality: in normal operation it controls transmission ratio changes, but when engine speed exceeds the threshold it simultaneously serves as a brake control interface. This universal design allows one device to perform multiple functions based on system state without requiring separate controls
Solution Approach 2:
The control system automatically detects when engine speed exceeds the threshold and autonomously converts downshift commands into brake applications without requiring driver awareness or manual intervention. The system serves itself by monitoring its own state and making appropriate control decisions
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
Enables safe and efficient control of vehicle speed while descending inclines by allowing maximum engine braking with proportional brake application, reducing the risk of engine damage and improving driver safety and control.
Implementation Method 1
a wheel of the vehicle, and/or attached vehicle, is braked in response to a downshift command from the driver
Data Source
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AI summary
A control system for a vehicle having electronic gearshift is provided. The system (30;60) comprises a multi-ratio transmission (34) arranged to deliver power from an engine (32) to driven wheels (20) of the vehicle (10) at a selected input-to-output ratio. A gearshift lever is connected to a controller. The system is operable in an engine overspeed prevention mode when the engine speed exceeds a predetermined threshold and in which mode a downshift in ratio is prevented. Any downshift command from the driver when in the engine overspeed prevention mode is translated into a braking force being applied to a wheel of the vehicle (10), and/or attached vehicle (12) such as a trailer.