What is the Function of an Automotive Vacuum Pump?
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The function of an automotive vacuum pump is to generate negative pressure, thereby increasing braking force. For vehicles powered by diesel engines, since the engine uses compression ignition, it cannot provide the same level of vacuum pressure at the intake manifold, necessitating the installation of a vacuum pump to supply the vacuum source. The vacuum pump is primarily used for power assistance. On one side, it continuously extracts air (approaching a vacuum, though absolute vacuum is impossible), while on the other side, it maintains atmospheric pressure. This creates negative pressure, generating a suction force or a pushing force, thus achieving power assistance. Introduction to Vacuum Pumps: A vacuum pump refers to a device or equipment that uses mechanical, physical, chemical, or physicochemical methods to evacuate a container and achieve a vacuum. In simpler terms, a vacuum pump is an apparatus that improves, generates, and maintains a vacuum in a sealed space through various methods. A vacuum booster pump is a large-diameter chamber, mainly composed of components such as the pump body, rotor, slider, pump cover, gears, and sealing rings. Note: Inside, there is a diaphragm (or piston) with a push rod in the middle, dividing the chamber into two parts—one connected to the atmosphere and the other linked to the engine intake manifold via a pipe. Working Principle of Automotive Vacuum Pumps: For vehicles with gasoline engines, which generally use spark ignition, a relatively high vacuum pressure can be generated at the intake manifold, providing sufficient vacuum source for the vacuum-assisted braking system. However, for vehicles powered by diesel engines, because the engine uses compression ignition, the intake manifold cannot provide the same level of vacuum pressure, requiring the use of a vacuum pump to supply the vacuum source. Additionally, some engines designed to meet certain automotive emission and environmental requirements also need a vacuum pump to provide adequate vacuum source to ensure the vehicle operates properly. The vacuum pump primarily outputs the pressure generated by the power servo system. However, in cases where the vacuum pump fails to function normally, the hydraulic system can still be manually operated to provide power assistance.
