Engine Warm-up Control via Intake Air Temperature Feedback
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Solution Overview
Problem
Conventional engine warm-up operation control systems for air-cooled general-purpose engines are inefficient due to ambient temperature influences on cylinder head temperature, leading to inappropriate fuel injection amounts and prolonged warm-up times, resulting in increased fuel consumption.
Innovation Solution
A control apparatus and method for a general-purpose internal combustion engine that calculates a warm-up correction coefficient based on engine speed and throttle opening, using a maximum output fuel injection amount searcher to optimize fuel injection and correct the coefficient, ensuring appropriate fuel injection amounts for efficient warm-up operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the warm-up correction coefficient is calculated based on cylinder head temperature, then the fuel injection amount can be corrected during warm-up operation, but the calculated fuel injection amount becomes inappropriate when ambient temperature significantly influences the cylinder head temperature
Solution Approach 1:
The patent changes the parameter used for warm-up correction from cylinder head temperature to intake air temperature. This parameter substitution resolves the issue where cylinder head temperature is influenced by ambient temperature, as intake air temperature directly reflects ambient conditions and provides a more accurate basis for calculating the warm-up correction coefficient under varying ambient temperatures.
2Reliability
If the fuel injection amount is increased during warm-up operation to ensure proper engine warming, then the engine can reach operating temperature, but the warm-up operation continues longer than necessary when the correction coefficient is inappropriate, increasing fuel consumption
Solution Approach 1:
The patent implements feedback control by continuously monitoring intake air temperature and using it to dynamically adjust the warm-up correction coefficient. This feedback mechanism ensures that fuel injection amount is precisely controlled based on actual warm-up conditions, preventing both insufficient warming and excessive fuel consumption during warm-up operation.
3Device complexity
If the warm-up correction coefficient is calculated using cylinder head temperature, then the system can operate with simple temperature sensing, but the system lacks adaptability to different ambient temperature conditions
Solution Approach 1:
The patent makes the temperature sensing system universal by using intake air temperature, which naturally reflects ambient temperature conditions. This single temperature parameter serves multiple functions: it indicates ambient temperature, determines warm-up correction coefficient, and adapts the system to different environmental conditions, eliminating the need for multiple temperature sensors or complex adaptation mechanisms.
Data Source
AI summary
In an apparatus for controlling a general-purpose engine used as a prime mover of an operating machine, the apparatus regulating a throttle opening such that an engine speed is converged to a desired engine speed, calculating a basic fuel injection amount based on the engine speed and throttle opening, and controlling engine warm-up operation by correcting the basic fuel injection amount with a correction coefficient to calculate a warm-up time fuel injection amount after engine start is completed and injecting fuel by the calculated amount, a fuel injection amount with which the engine output becomes maximum is searched based on the throttle opening regulated in response to increase/decrease operation of the warm-up time fuel injection amount conducted when the engine speed is constant; and the correction coefficient is corrected using the searched fuel injection amount. With this, a warm-up correction coefficient appropriate for the engine warm-up condition can be calculated.