What is the function of the intake manifold pressure sensor?
2 Answers
The intake manifold pressure sensor, abbreviated as MAP, is a key component in the D-type fuel injection system of gasoline engines. Its function is equivalent to that of an air flow meter, primarily used to measure the amount of air entering the engine and provide this data to the engine control computer as the basis for controlling fuel injection quantity and ignition timing. Below is more information about the intake manifold pressure sensor: 1. The working principle of the intake manifold pressure sensor involves measuring the absolute pressure in the intake pipe to determine air density. Combined with the engine's speed, it calculates the amount of air entering. This indicates that the manifold between the throttle and the intake valve in a typical engine is generally in a vacuum state. 2. Except for turbocharged engines, the intake power in ordinary gasoline engines comes from the suction of the pistons. In other words, the piston end is the active end, while the throttle is usually closed, leading to demand exceeding supply and thus creating a vacuum in the manifold. Even when the throttle is fully open, due to the resistance of air flow and certain lag, with the active end being the piston, a vacuum is still generated.
The intake manifold pressure sensor acts like a tiny monitor in your car, specifically measuring the changes in air pressure within the intake manifold. It relays this information in real-time to the engine control unit (ECU), which then determines the precise amount of fuel needed to match the incoming airflow. When functioning properly, your car runs smoothly, fuel-efficiently, and with ample power. However, if it fails, fuel delivery becomes erratic, causing engine shuddering, sluggish acceleration, and even a dramatic spike in fuel consumption. Once, while driving to the mountains, my car kept hiccuping—turned out this sensor was faulty. After repairs, it ran smoothly again. During routine maintenance, ask your mechanic to check it to avoid the risk of breaking down mid-journey. Don’t underestimate its small size; it plays a crucial role in daily driving safety and your wallet.
