Automobile intake pressure sensor function
Monitor intake manifold pressure
The intake pressure sensor is connected to the intake manifold through a vacuum tube to detect the absolute pressure change in the intake manifold behind the throttle valve in real time. These pressure changes are closely related to the speed and load of the engine, and the sensors convert these mechanical changes into electrical signals that are transmitted to the ECU.
Optimize fuel injection
Based on the pressure signal provided by the sensor, the ECU accurately calculates the amount of fuel required by the engine. When the engine load increases, the intake manifold pressure decreases, the sensor output signal increases, and the ECU increases the fuel injection volume accordingly. Otherwise, it will decrease. This dynamic adjustment ensures efficient operation of the engine under different working conditions.
Control ignition timing
The intake pressure sensor also helps the ECU adjust the ignition timing. When the engine load increases, the ignition advance Angle will be delayed appropriately. When the load is reduced, the ignition advance Angle will advance. This adjustment helps improve the engine's power performance and fuel economy.
Auxiliary air flow calculation
In the Type D fuel injection system, the intake pressure sensor is used in conjunction with the air flow meter to measure the intake volume indirectly, thus calculating the air flow more accurately. This collaborative work further optimizes fuel injection and engine performance.
Fault detection and protection
The intake pressure sensor is capable of detecting abnormal pressure changes in the intake manifold, such as clogs or leaks, and sending signals to the ECU. This helps detect engine failures in time and take protective measures to avoid further damage.
Types and working principles
Common intake pressure sensors include varistor and capacitive types. The varistor sensor changes the resistance through the deformation of the silicon diaphragm and outputs the electrical signal. The capacitive sensor changes the capacitance value through the deformation of the diaphragm and outputs the pulse signal. Both sensors are widely used in modern vehicles for their high precision and fast response.
Sum up
Intake pressure sensor is one of the core components of automobile engine control system, its role is not only limited to monitoring pressure, but also involved in fuel injection, ignition timing, air flow calculation and fault detection. By precisely controlling these parameters, sensors significantly improve engine performance, fuel economy and emissions.
Automotive intake pressure sensor (intake pressure sensor) is one of the core components of the fuel injection system, its failure will cause the engine control unit (ECU) can not accurately adjust the air-fuel ratio. The following are the main symptoms and causes of the fault:
Core symptom presentation
Difficulty or inability to start the engine
Abnormal sensor signals will cause the ECU to fail to calculate the correct fuel injection amount, directly affecting ignition and fuel injection.
If the sensor line is broken or short-circuited, the ECU may completely lose the intake pressure data, resulting in startup failure.
Abnormal power output
poor acceleration or power decline : the sensor cannot adjust the signal with the change of vacuum degree, and the ECU miscalculates the air intake, resulting in the oil injection quantity deviation.
erratic idle speed : When the mixture is too thick or too thin, the engine may jitter or speed fluctuation.
combustion anomaly
Black smoke from the exhaust pipe : the mixture is too thick to cause incomplete combustion, commonly seen in rapid acceleration.
intake pipe tempering : When the mixture is too thin, unburned gas ignits in the intake pipe.
Fault cause classification
The sensor itself
Internal strain gauge or circuit failure (e.g. semiconductor strain gauge failure).
The output signal voltage exceeds the normal range (such as voltage drift).
external associated failure
The vacuum hose is blocked or leaking, which affects the pressure transmission.
Improper installation of the seal ring leads to blockage of the pressure inlet (signal mutation during pressure).
Diagnostic suggestion
Preliminary examination
Observe whether the fault light is on (some models will trigger the OBD fault code).
Check the vacuum pipe connections and sensor wiring harness.
Professional testing
Use the diagnostics to read real-time data streams and compare standard pressure values.
Test whether the sensor output voltage varies with the throttle opening.
tip : If the above symptoms are accompanied by fault codes (such as P0105/P0106), the sensor and related circuits should be checked first. Long-term neglect may result in damage to the three-way catalytic converter or a significant increase in fuel consumption.
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