A "bypass valve car" refers to a car equipped with a hydraulic bypass valve in its brake system, designed to maintain braking ability in the event of a pressure loss in either the front or rear brakes. More specifically, the term most likely refers to cars with a bypass valve connecting the front and rear brakes.
Here's a more detailed explanation:
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Function: The primary function of the bypass valve is to ensure that at least one set of brakes (front or rear) remains operational if the hydraulic pressure in the other set fails. If pressure is lost in one brake circuit, the bypass valve diverts brake fluid to the functioning circuit.
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Mechanism: The bypass valve typically operates using a spring-loaded mechanism. This mechanism opens when the pressure difference between the front and rear brake circuits exceeds a predetermined threshold (either too high or too low pressure in one circuit).
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Purpose: The main reason for having a bypass valve is safety. By ensuring that at least one set of brakes is always functional, the car remains controllable even in the event of a brake line rupture or other hydraulic failure.
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Example Scenario: If a brake line bursts in the front brake circuit, the bypass valve will close off the front circuit and direct all available hydraulic pressure to the rear brakes, allowing the driver to stop the vehicle, albeit with reduced braking power.
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Importance: While modern cars have sophisticated anti-lock braking systems (ABS) and other electronic brake force distribution (EBD) systems that provide superior braking performance and safety, bypass valves offer a simple, mechanical failsafe to prevent complete brake failure.
In essence, a bypass valve in a car's braking system acts as a safety net, ensuring some braking capability is retained even in the presence of a hydraulic pressure loss in either the front or rear brakes.
