Diaphragm Carburetor Bubble Discharge Path
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Solution Overview
Problem
Diaphragm-type carburetors face issues with fuel vapor bubbles forming in the metering chamber due to temperature fluctuations, leading to unstable fuel pressure and lean air-fuel mixtures, which can cause engine speed reduction and stoppages, and existing solutions do not completely address these issues.
Innovation Solution
A diaphragm-type carburetor with a bubble discharge path equipped with check valves and a pump mechanism that uses the pulsation pressure from the crank chamber or intake pipe to withdraw and discharge fuel vapor bubbles from the metering chamber, synchronizing with the throttle shaft's opening and closing operations to prevent bubbles from entering the intake passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the metering chamber is filled only with liquid fuel to achieve stable pressure, then fuel pressure stability is improved, but fuel vapor bubbles may still form due to temperature fluctuations and pressure changes, leading to lean air-fuel mixtures and engine performance issues
Solution Approach 1:
The patent extracts and removes fuel vapor bubbles from the metering chamber using a dedicated bubble discharge path equipped with check valves and a pump mechanism. This separates the harmful vapor phase from the liquid fuel, allowing the metering chamber to maintain stable liquid fuel pressure while actively eliminating vapor bubbles that would otherwise cause lean air-fuel mixtures and engine performance issues.
Solution Approach 2:
The patent introduces a bubble discharge path with check valves and a pump mechanism as an intermediary system between the metering chamber and the external environment. This intermediary mechanism selectively removes fuel vapor bubbles while maintaining the liquid fuel supply, resolving the contradiction between pressure stability and vapor elimination without disrupting the primary fuel metering function.
2Object-affected harmful factors
If existing bubble discharge techniques are used, then some fuel vapor removal is achieved, but the air-fuel mixture becomes excessively lean and fuel pressure becomes unstable
Solution Approach 1:
The patent employs a feedback mechanism where the pump mechanism is activated by pulsation pressure from the crank chamber or intake pipe, which naturally correlates with engine operation cycles. The check valves provide one-way flow control that responds to pressure differentials, creating a self-regulating system that removes vapor bubbles only when and where needed, preventing excessive lean conditions while maintaining fuel pressure stability.
Solution Approach 2:
The bubble discharge system utilizes the engine's own pulsation pressure from the crank chamber or intake pipe to drive the pump mechanism, eliminating the need for an external power source. The system serves itself by using the natural pressure fluctuations during engine operation to activate vapor bubble removal, ensuring the process occurs automatically without external intervention or additional energy consumption.
3Reliability
If a pump mechanism is added to discharge fuel vapor bubbles, then bubble removal effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent merges the bubble discharge function with the existing fuel pump system by using the same pump mechanism for both fuel delivery and vapor bubble removal. The bubble discharge path is integrated into the existing carburetor structure, combining multiple functions (fuel pumping, vapor removal, pressure regulation) into a unified system that reduces overall complexity despite adding bubble discharge capability.
Solution Approach 2:
The pump mechanism is activated automatically by pulsation pressure from the engine's crank chamber or intake pipe, eliminating the need for separate control systems, motors, or external power sources. This self-service activation method adds minimal complexity while achieving reliable bubble discharge effectiveness synchronized with engine operation cycles.
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
This solution stabilizes fuel pressure and prevents lean air-fuel mixtures, ensuring consistent fuel supply to the engine and improving engine operation by securely removing fuel vapor bubbles without affecting engine operation timing.
Implementation Method 1
A diaphragm-type carburetor with a bubble discharge path equipped with check valves and a pump mechanism that uses the pulsation pressure from the crank chamber or intake pipe to withdraw and discharge fuel vapor bubbles from the metering chamber
Implementation Method 2
a bubble discharge path connecting the metering chamber to at least one other predetermined discharge portions and provided with a check valve in each of an inlet side and an outlet side
Implementation Method 3
a metering chamber having a diaphragm and a lever mechanism and provided with fuel at a desired constant pressure
Data Source
AI summary
The carburetor prevents an air-fuel mixture from becoming excessively lean and prevents a fuel pressure from becoming unstable, thereby making it possible to stably supply a fuel to an engine, in a diaphragm-type carburetor with a pressure regulator. A diaphragm-type carburetor includes a fuel pump using a pulsation pressure generated in a crank chamber of an engine or an intake pipe as a driving force, and a metering chamber having a diaphragm and a lever mechanism and provided with fuel at a desired constant pressure. The diaphragm-type carburetor includes a bubble discharge path connecting the metering chamber to other predetermined discharge portions and with a check valve in each of an inlet side and an outlet side. A bubble removing pump is connected to the bubble discharge path, withdraws the bubble to the bubble discharge path from the metering chamber in conjunction with a closing or opening operation of a throttle shaft by a driver or operator and discharging the withdrawn bubble to the discharge portion in conjunction with an opening or closing operation of the throttle shaft.