* Electrically Operated Solenoid Valve: This is the most common type, especially in modern vehicles and machinery. The switch activates a solenoid, which is an electromagnet. When the switch is activated, the solenoid energizes, creating a magnetic field that moves a plunger, blocking the fuel line. When the switch is deactivated, the solenoid releases, and fuel flow resumes. This method is clean, reliable, and allows for remote operation.
* Manually Operated Valve: Simpler systems might use a manually operated valve. This could be a lever, knob, or wheel that physically blocks or opens the fuel line. These are less common in modern applications due to their lack of remote operation capability and potential for leakage.
* Gravity-Fed Systems with a Shutoff Valve: In gravity-fed systems (where fuel flows from a tank above the engine), a simple valve can be placed in the fuel line. Closing this valve cuts off the fuel supply. This is a low-tech solution and prone to leakage if the valve isn't properly sealed.
Regardless of the specific mechanism, the fundamental principle remains the same: interrupting the fuel supply to prevent the engine from combusting fuel and thus stopping its operation. The cutoff switch is typically used as a safety feature, to prevent fuel leaks in case of an accident, or for emergency shutdowns. It can also be used intentionally to stop the engine in various situations.
