Engine Start-Stop Control via Brake Pedal Force Thresholds
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Solution Overview
Problem
Current engine start-stop systems are inefficient as they cannot accurately anticipate when an engine should be shut down, leading to short, unproductive shutdowns that consume more fuel than they save, and excessive idling causes engine wear and reduces fuel economy.
Innovation Solution
A computer-implemented method that allows drivers to signal engine start-stop devices to turn off or restart the engine by varying brake pedal force, using a combination of fast and slow filters to interpret the driver's intent based on brake pedal force thresholds, ensuring engine control only when the vehicle is stopped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If automatic engine stop-start systems are implemented, then fuel economy can be improved during idle periods, but the systems cannot accurately anticipate when engine shutdown is appropriate, leading to short unproductive shutdowns that consume more fuel than they save
Solution Approach 1:
The system uses feedback from brake pedal force sensors to continuously monitor driver braking behavior and adjust engine control decisions accordingly. The ECU processes real-time brake force data to determine driver intent, creating a closed-loop control system that improves the accuracy of engine shutdown timing based on actual driver actions rather than relying solely on predetermined conditions.
Solution Approach 2:
The system enables the driver to directly control engine shutdown and restart decisions through their natural braking actions. By applying increasing force to the brake pedal after the vehicle stops, the driver self-initiates engine shutdown without requiring separate controls or complex system interpretations, making the system serve the driver's intent directly.
2Object-affected harmful factors
If engine shutdown is triggered by brake pedal detection, then engine wear from idling can be reduced, but the system may misinterpret normal braking as engine shutdown requests
Solution Approach 1:
The system dynamically adjusts the interpretation of brake pedal force based on the vehicle's motion state. During vehicle deceleration, normal braking forces are expected and do not trigger engine shutdown. Only after the vehicle comes to a complete stop does the system consider increasing brake force as a potential engine shutdown request. This dynamic state-dependent interpretation prevents misidentification of driver intent while accurately detecting genuine shutdown requests.
Solution Approach 2:
The system establishes predetermined force thresholds that must be exceeded to trigger engine shutdown, creating a clear distinction between normal braking and shutdown requests. By setting these thresholds in advance and requiring sustained force above the threshold after stopping, the system prevents premature or accidental engine shutdown while maintaining sensitivity to genuine driver intent.
3Reliability
If multiple threshold values are used to determine engine shutdown, then false triggers can be avoided, but the system complexity increases
Solution Approach 1:
The brake pedal force range is segmented into multiple zones with different meanings: normal braking forces during motion, moderate forces after stopping, and high forces indicating shutdown intent. By dividing the force spectrum into distinct segments with specific threshold values, the system achieves reliable differentiation between various driver actions without requiring complex algorithms, as each segment has clear boundaries and interpretations.
Data Source
AI summary
This invention provides a computer implemented method which allows the driver to request engine shut down and engine and restarts the engine of a motor vehicle by changing driver brake pedal force, that is, the force which the driver applies to the brake pedal, after the vehicle has stopped. After the vehicle has stopped, changes in the driver brake pedal force are compared to threshold values to determine if the driver is requesting an engine stop or an engine start.