Adaptive Engine Stop-Start Control Using Driver Behavior Cost Functions
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Solution Overview
Problem
Existing engine stop-start systems fail to balance fuel efficiency and driver annoyance, as they often stop the engine too frequently or not frequently enough, leading to minimal fuel savings and inconsistent engine behavior.
Innovation Solution
The system automatically stops and starts the engine based on vehicle operating conditions, adjusting the engine stopping criteria using cost functions that weigh fuel efficiency against driver behavior, such as brake release patterns and acceleration intentions, to optimize fuel conservation and reduce driver annoyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is stopped immediately when vehicle speed is zero and brake is depressed, then fuel conservation is maximized, but driver annoyance increases due to premature stopping before driver expects acceleration
Solution Approach 1:
The engine stopping criteria are made dynamic by adjusting the effective stop threshold based on detected driver characteristics. The controller modifies stopping behavior in real-time based on whether the driver is identified as impatient or patient, allowing the system to adapt between immediate stopping (for fuel saving) and delayed stopping (for driver convenience).
Solution Approach 2:
The system uses feedback from monitoring driver behavior patterns (brake release timing, acceleration requests) to identify driver characteristics and adjust engine stopping criteria accordingly. This closed-loop approach allows the controller to learn driver preferences and optimize stopping decisions to balance fuel savings with driver satisfaction.
2Ease of operation
If the engine is allowed to idle for extended time before stopping, then driver annoyance is reduced by stopping at expected time, but fuel conservation is minimized due to prolonged idle operation
Solution Approach 1:
The system dynamically adjusts the engine stop delay threshold based on driver characteristic detection. For patient drivers who wait longer before requesting acceleration, the controller delays engine stopping accordingly to match driver expectations. For impatient drivers, the controller stops the engine sooner to maximize fuel savings.
Solution Approach 2:
The controller changes the time parameter of engine stopping by adjusting the effective stop threshold based on driver behavior analysis. This parameter modification allows the system to extend idle time when driver characteristics indicate patience, while reducing idle time when impatience is detected, thus optimizing both driver satisfaction and fuel economy.
3Device complexity
If standard engine stopping criteria are applied uniformly to all drivers, then system simplicity is maintained, but fuel efficiency is optimized for only a subset of drivers
Solution Approach 1:
The system performs self-characterization by automatically detecting driver characteristics through monitoring of brake release patterns and acceleration requests. This self-service approach allows the controller to identify whether a driver is impatient or patient without external intervention, enabling adaptive stopping criteria to be applied automatically based on the detected driver type.
Solution Approach 2:
The control system transitions from static, uniform stopping criteria to dynamic, adaptive criteria that automatically adjust based on detected driver characteristics. This dynamic approach allows the system to optimize fuel efficiency for different driver types while maintaining reasonable complexity through automated detection and adjustment mechanisms.
Data Source
AI summary
A method and system for improving automatic engine stopping and starting is presented. In one example, the method adjusts conditions for engine stopping in response to operating conditions that are evaluated according to one or more cost functions. The method may improve vehicle fuel economy and limit driver annoyances.