Carburetor Control System for Stable Cold Idling
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Solution Overview
Problem
Conventional carburetor control systems face instability in choke valve opening due to intake negative pressure pulsation during cold idling, leading to inefficient fuel injection and unstable engine idling.
Innovation Solution
A carburetor control system that mechanically opens the choke valve to an intermediate degree, synchronized with the throttle valve's idling position, using a drive arm and choke return spring to stabilize the fuel injection, thereby ensuring a stable and fuel-efficient cold idling state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the set load of the relief spring is set as small as possible to facilitate the opening of the choke valve with intake negative pressure, then the choke valve can open more easily, but the degree of opening of the choke valve becomes unstable due to the pulsation of the intake negative pressure
Solution Approach 1:
The patent introduces an intermediary mechanism (the relief mechanism with relief spring) that mediates between the intake negative pressure and the choke valve. This intermediary structure allows the choke valve to respond smoothly to pressure changes while filtering out the unstable pulsations, achieving both easy opening and stable operating position.
Solution Approach 2:
The patent changes the parameter of spring load (set load) of the relief spring to an optimal value that is not too small. This parameter adjustment allows the relief mechanism to effectively smooth out the pulsation of intake negative pressure while still enabling the choke valve to open easily when needed, resolving the contradiction between ease of operation and stability.
2Loss of energy
If the set load of the relief spring is set sufficiently small to prevent excessive fuel injection, then fuel efficiency improves, but the degree of opening of the choke valve becomes unstable due to intake negative pressure pulsation
Solution Approach 1:
The patent optimizes the parameter of relief spring load to a specific range that balances fuel efficiency and stability. By setting the load to an appropriate value (not sufficiently small), the system prevents excessive fuel injection while maintaining stable choke valve operation, resolving the contradiction between fuel efficiency and operational stability.
Solution Approach 2:
The relief mechanism acts as an intermediary that controls the relationship between intake negative pressure and fuel injection. It smooths out the pulsations before they can cause unstable fuel injection, thereby enabling fuel-efficient operation with stable choke valve positioning.
3Productivity
If the choke valve is controlled to a fully closed state by the automatic choke device during cold idling, then fuel injection is maximized for cold start, but the engine cannot maintain a stable and fuel-efficient idling state
Solution Approach 1:
The patent introduces dynamic control of the choke valve opening degree during cold idling. Instead of maintaining a fully closed state, the system dynamically adjusts the opening to an intermediate position using the relief mechanism, allowing the engine to transition from a high-fuel-injection cold start state to a stable, fuel-efficient idling state.
Solution Approach 2:
The patent changes the operating parameter of the choke valve from a binary state (fully closed or fully open) to a controlled intermediate opening degree. This parameter adjustment enables the engine to maintain both adequate fuel injection for cold start and stable, fuel-efficient idling operation simultaneously.
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
The system achieves stable and fuel-efficient cold idling by optimizing fuel injection through the intermediate choke valve opening, reducing fluctuations and improving engine performance.
Implementation Method 1
a choke return spring urging a choke lever for opening and closing a choke valve in a direction to close the choke valve
Implementation Method 2
an automatic choke device connected to the choke lever to open the choke valve in accordance with an increase in temperature of the engine
Data Source
AI summary
A carburetor control system includes: a governor device that is coupled to a throttle lever, opens a throttle valve when an operation of an engine is stopped, and opens or closes the throttle valve in accordance with a rotational number of the engine when the engine is in operation; a choke return spring urging a choke lever in a direction to close a choke valve; and an automatic choke device opening the choke valve in accordance with an increase in temperature of the engine. In the carburetor control system, the throttle lever is provided with a drive arm pivoting the choke lever, during a cold operation of the engine, to a position where the choke valve is at an intermediate degree of opening in operative connection with the throttle lever being pivoted by the governor device to a position where the throttle valve is at a degree of opening for idling or a position in a vicinity thereof. Accordingly, it is possible to mechanically open the choke valve to a predetermined intermediate degree of opening, when the engine is in a cold idling state, in operative connection with the throttle valve, so as to be capable of ensuring a fuel-efficient and stable idling state.