Engine Start Control Around Centrifugal Clutch-In Speed
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Solution Overview
Problem
Existing manual-recoil type working machines require time to start the engine and have limited control over air and fuel supply, leading to inefficient engine starting.
Innovation Solution
An engine starting system with a centrifugal clutch and control device that accelerates the engine to a rotation speed higher than the clutch-in speed, then suppresses it to equal or below that speed, adjusting air and fuel supply through a throttle valve and fuel valve, with feedback control to stabilize the rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lift-up member is operated to increase throttle opening degree to start the engine, then the engine can be started, but the starting process takes time and control is limited
Solution Approach 1:
The control device performs preliminary actions by automatically adjusting the throttle opening degree and fuel supply before the engine reaches operating speed. The system pre-configures optimal air-fuel mixture ratios and throttle positions during the starting phase, eliminating the need for manual throttle operations and reducing starting time.
Solution Approach 2:
The control device continuously monitors engine rotation speed and adjusts throttle opening degree and fuel supply in real-time based on feedback from speed sensors. This closed-loop control ensures optimal air-fuel mixture during starting while automatically adapting to changing engine conditions, enabling quick and reliable engine startup.
2Speed
If the engine is accelerated to high rotation speed, then the engine starts quickly, but the rotation speed exceeds clutch-in speed causing clutch engagement issues
Solution Approach 1:
The control device applies preliminary anti-action by detecting when engine rotation speed approaches clutch-in speed and proactively reducing fuel supply and throttle opening degree to prevent excessive speed buildup. This anticipatory control prevents clutch engagement shocks and protects the centrifugal clutch from damage while maintaining quick starting performance.
Solution Approach 2:
The control device dynamically adjusts the throttle opening degree and fuel supply based on real-time engine rotation speed. The system transitions from aggressive fuel injection during acceleration to restrained supply near clutch-in speed, creating a dynamic control strategy that optimizes both starting speed and clutch protection throughout the engine startup sequence.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick and appropriate engine starting, even for users with low skill, by simplifying the starting operation and ensuring the engine reaches a usable state rapidly.
Implementation Method 1
a centrifugal clutch configured to transmit a driving force of the engine to a driven device
Data Source
AI summary
Provided is an easy engine starting system including: an engine; a centrifugal clutch configured to transmit a driving force of the engine to a driven device; and a control device configured to adjust output of the engine. When the engine is to be started, the engine is accelerated at start engine output which enables the engine to reach a rotation speed higher than a clutch-in rotation speed. The control device has suppression control of suppressing, at the start engine output, the rotation speed to a rotation speed equal to or lower than the clutch-in rotation speed.