Integrated Ignition and Fuel Shutoff Lever Mechanism
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Solution Overview
Problem
During transport of engine-driven products, fuel can leak from the fuel tank into the combustion chamber and crankcase, diluting engine oil and causing damage, as existing technologies do not effectively prevent fuel flow when the engine is not in use.
Innovation Solution
A carburetor assembly with an integrated ignition and fuel shutoff device, featuring a pivoting lever that manually controls a microswitch to ground the ignition coil and a petcock valve to shut off fuel supply, ensuring the engine cannot start and preventing excess fuel from reaching the combustion chamber and crankcase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing separate fuel shut-off and ignition shutoff devices are used, then the engine can be stopped, but fuel can still leak into the combustion chamber and crankcase during transport, diluting engine oil and causing damage
Solution Approach 1:
The patent combines the fuel shut-off valve and ignition shutoff switch into a single integrated lever mechanism. When the lever is moved to the shut-off position, it simultaneously closes the fuel valve and grounds the ignition coil through a microswitch, ensuring both fuel supply is blocked and ignition is prevented in one action.
Solution Approach 2:
The integrated lever performs preliminary protective actions by simultaneously shutting off both fuel supply and ignition before transport begins. This prevents fuel from entering the combustion chamber and crankcase in advance, eliminating the risk of oil dilution before the harmful effect can occur.
2Reliability
If a single lever controls both fuel shut-off and ignition shutoff, then simultaneous protection is achieved, but the device complexity increases compared to separate controls
Solution Approach 1:
The single lever serves multiple functions: it acts as the operating handle for the fuel valve, the actuator for the microswitch, and the mechanical link that simultaneously controls both fuel shut-off and ignition grounding. This multi-functionality reduces the number of separate components needed while achieving reliable simultaneous protection.
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 effectively prevents engine start-up and fuel leakage during transport, protecting the engine by ensuring the ignition system is shut off and fuel supply is halted, thereby preventing fuel from diluting engine oil and causing damage.
Implementation Method 1
a pivoting lever that manually controls a microswitch to ground the ignition coil
Implementation Method 2
a petcock valve to shut off fuel supply
Data Source
Figure 1
Figure 2
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AI summary
A carburetor assembly includes a carburettor (30), a fuel supply valve (25), a valve member (95) and a normally open switch (45). The fuel supply valve (25) is coupled to the carburetor housing and is fluidly connected to the carburettor (30). The fuel supply valve (25) includes a lever (65) pivotable between first and second positions. The valve member (95) is configured to move in response to the lever (65) such that fuel is allowed to flow to the carburettor (30) when the lever (65) is in the first position and fuel is not allowed to flow to the carburettor (30) when the lever (65) is in the second position. The normally open switch (45) is adjacent the fuel supply valve (25) and includes a switch actuator (85). The lever (65) is configured to engage and release the switch actuator (85) to move the switch actuator (85) between a non-actuated position and an actuated position respectively when the lever (65) moves between the first and second positions.