Engine Auto Stop Inhibit Algorithm Based on Current Demand
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Solution Overview
Problem
Existing engine auto stop systems in micro-hybrid vehicles may cause fuel economy inefficiencies due to premature engine shutdowns when electrical load current demands exceed battery capabilities during engine stop/start events, leading to voltage drops and potential system failures.
Innovation Solution
A controller system that estimates the current demand of vehicle electrical loads and compares it to a threshold current to determine whether to inhibit engine auto stops, preventing shutdowns if the demand exceeds the threshold and allowing shutdowns if it remains below, thereby maintaining battery voltage within safe limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is stopped during idle intervals to improve fuel economy, then fuel consumption is reduced, but voltage drops and potential system failures occur when electrical load current demands exceed battery capabilities
Solution Approach 1:
The controller estimates the current demand of electrical loads before the engine auto stop is executed and compares it with a threshold current. This preliminary assessment prevents engine shutdown when electrical demand would exceed battery capabilities, avoiding voltage drops and system failures while still enabling fuel-saving stops when conditions are favorable.
2Loss of energy
If the engine is stopped during idle intervals to reduce idle time, then fuel economy is improved, but premature shutdowns occur when electrical load demands exceed battery capabilities
Solution Approach 1:
The controller continuously monitors and estimates the current demand of electrical loads, using this feedback information to make intelligent decisions about engine auto stop execution. By comparing estimated current demand with a threshold, the system optimizes the balance between reducing idle energy loss and maintaining operational efficiency, preventing premature shutdowns when electrical demand is high.
Data Source
AI summary
A vehicle includes an engine and at least one controller. The at least one controller periodically determines an estimated current to be demanded by vehicle electrical loads during an auto stop of the engine, compares the estimated current with a threshold current, and inhibits an auto stop of the engine if the estimated current is greater than the threshold current for a predetermined period of time.