Portable Engine Throttle Control for Run-on Prevention
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Solution Overview
Problem
Portable working machines, such as blowers, experience the Run-on phenomenon and after burn phenomenon due to incomplete engine shutdown, leading to inefficiencies and reduced operability, as existing control systems either fail to prevent these issues or compromise operability.
Innovation Solution
An operating apparatus with a first operating device for the throttle valve and a second device to regulate its position, allowing full closure of the throttle valve during engine shutdown, preventing air-fuel mixture suction and enhancing operability by simplifying the control structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the engine stop switch is operated with the throttle valve at idle opening degree, then the engine shutdown process is simplified, but the Run-on phenomenon occurs due to air-fuel mixture suction into the cylinder
Solution Approach 1:
The system performs preliminary action by automatically closing the throttle valve before the engine stops rotating. When the stop switch is activated, the throttle valve is first set to the fully closed state, preventing air-fuel mixture suction, and then the engine is allowed to stop rotating naturally, thereby preventing the Run-on phenomenon while maintaining simple operation
Solution Approach 2:
A control unit is introduced as an intermediary between the stop switch and the throttle valve. The control unit receives the stop signal and automatically adjusts the throttle valve position, mediating the shutdown process to ensure the throttle valve is fully closed before engine rotation stops, thus preventing harmful Run-on phenomenon without requiring manual throttle adjustment
2Object-generated harmful factors
If the throttle valve is fully closed before engine shutdown, then the Run-on phenomenon is prevented, but the engine shutdown process becomes more complex
Solution Approach 1:
The system implements self-service by automatically managing the throttle valve closure sequence through the control unit. When the stop switch is activated, the control unit autonomously closes the throttle valve and manages the shutdown process without requiring additional manual operations from the user, thereby preventing Run-on phenomenon while maintaining simple user interaction
Solution Approach 2:
The control functions for the throttle valve and engine shutdown are merged into a single automated sequence controlled by the control unit. The control unit integrates the throttle valve control and engine stop coordination, combining multiple control actions into one unified shutdown operation that prevents Run-on phenomenon without increasing user operational complexity
3Object-generated harmful factors
If a separate throttle closure device is added to prevent Run-on phenomenon, then the harmful factors are reduced, but the control handle structure becomes more complex
Solution Approach 1:
The control unit is designed to perform multiple functions: it controls both the throttle valve position and coordinates the engine shutdown sequence. By making the control unit universal, the patent avoids adding separate dedicated devices for throttle closure, thereby preventing after burn phenomenon without significantly increasing control handle structure complexity
Solution Approach 2:
The control unit serves as an intermediary that automatically manages the throttle valve closure without requiring separate manual control mechanisms. This electronic mediation eliminates the need for additional mechanical throttle closure devices, reducing structural complexity while effectively preventing after burn phenomenon through automated throttle control
Data Source
AI summary
An operating apparatus of an engine in a portable working machine improves an operability of a throttle lever while preventing a Run-on phenomenon or the like. The operating apparatus is provided with a first operating device for operating a throttle valve of the engine in a range from a fully closed state to a fully opened state, a switch for switching the engine between an operable state and a stoppable state, and a second operating device for operating the switch. The second operating device is structured so as to regulate an operation position of the first operating device at a time of operating the switch such that the engine is brought into the operable state, and to allow the first operating device to fully close the throttle valve at a time of operating the switch such that the engine is brought into the stoppable state.