Predictive Engine Stop Control for Fuel Economy
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Solution Overview
Problem
Automatic engine stopping in vehicles can result in prolonged engine cranking times when the battery is low or the engine cranking system is degraded, leading to decreased fuel economy and occupant dissatisfaction.
Innovation Solution
Implementing a method to prohibit automatic engine stopping when estimated engine cranking time exceeds a threshold, using predictive algorithms based on battery state of charge, cranking current, and starter motor resistance to ensure shorter cranking times and maintain fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If automatic engine stopping is implemented to conserve fuel, then fuel economy is improved, but engine cranking time may be prolonged when battery state of charge is low or cranking system is degraded
Solution Approach 1:
The system performs preliminary assessment of battery state of charge and cranking system condition before enabling automatic engine stop. By evaluating these parameters in advance, the system prevents engine stops that would result in prolonged cranking times, thereby maintaining both fuel economy benefits and acceptable restart performance.
Solution Approach 2:
The system continuously monitors battery state of charge, cranking current, and engine restart performance to dynamically adjust automatic stop decisions. This feedback mechanism allows the system to learn from actual cranking times and adapt to aging components, preserving fuel economy while avoiding excessively long cranking events.
2Use of energy by moving object
If automatic engine stopping is permitted without restrictions, then fuel economy gains are maximized, but occupant satisfaction decreases due to objectionable long cranking times
Solution Approach 1:
The system changes the operational parameters of automatic engine stop based on real-time conditions. By adjusting the decision criteria for engine stopping based on battery state of charge, temperature, and historical cranking performance, the system optimizes the balance between fuel economy and occupant comfort dynamically rather than using fixed rules.
3Device complexity
If engine cranking system components are allowed to degrade, then system complexity is reduced, but engine cranking time exceeds threshold and system functionality is compromised
Solution Approach 1:
The system performs self-diagnosis and self-adjustment by monitoring its own cranking performance and battery conditions. It automatically adapts to aging components by adjusting automatic stop decisions based on actual cranking times and electrical system performance, allowing the system to maintain functionality without additional complexity from external monitoring systems.
Data Source
AI summary
A method for allowing or prohibiting automatic engine stopping and starting is presented. In one example, an engine cranking time is predicted and compared to a threshold value to determine whether or not automatic engine stopping and starting is to be allowed or prohibited. The predicted engine cranking time is a metric for judging whether or not vehicle occupants might find a possible subsequent vehicle operation delay objectionable due to an engine starting event.