What does a car engine speed sensor mean
The speed sensor of an automotive engine is a key component that converts engine speed into an electrical signal and is one of the important sensors in the automotive electronic control system. It detects the rotational motion of the crankshaft or camshaft, monitors the engine's operating parameters (such as rotational speed, rotation Angle, etc.) in real time, and converts these physical quantities into electrical signals to transmit to the engine control unit, thereby achieving precise control of parameters such as fuel injection and ignition timing, ensuring the efficient and stable operation of the engine.
Core function
It is mainly used to monitor engine speed and crankshaft position, provide reference signals for the control unit, optimize fuel injection volume and ignition timing, enhance power performance and reduce fuel consumption.
Types and Applications
Common types include magnetic sensitive type, photoelectric type, Hall effect type, etc., which are widely used in fields such as automobiles, CNC machine tools, and wind power generation.
A damaged speed sensor can cause systematic faults such as difficult starting, abnormal power, and instrument alarms in the vehicle , directly affecting the engine operation status and driving safety.
Youdaoplaceholder0 Core fault phenomenon
Youdaoplaceholder0 Difficulty in starting : It is manifested as the need for multiple ignitions or stepping on the accelerator to start, as the sensor cannot accurately transmit the crankshaft position signal, resulting in the failure of fuel injection control.
Youdaoplaceholder0 idle speed anomaly :
The engine is shaking significantly and the tachometer pointer fluctuates violently.
It is prone to sudden stalling when waiting at traffic lights.
Youdaoplaceholder0 power performance decline :
Weak acceleration and sluggish throttle response.
The maximum speed is restricted, and a "limping mode" may occur to enforce speed limits.
Youdaoplaceholder0 gives rise to safety hazards
Abnormal increase in fuel consumption : Due to the conservative fuel injection strategy adopted by the ECU, the imbalance of the mixture concentration leads to a 30%-50% reduction in fuel efficiency.
Youdaoplaceholder0 instrument false alarm and system interlocking fault :
The engine fault light, ABS light, battery light and other alarm light groups all lit up collectively.
The gear shifting logic of the automatic transmission is chaotic, and gear jamming may occur.
Youdaoplaceholder0 risk of extreme operating conditions :
Sudden abnormal surge in engine speed during driving (commonly seen in fan speed sensor failure).
When decelerating, the engine completely stalls, causing the steering/braking assist to fail.
Youdaoplaceholder0 Inspection and maintenance points
Diagnostic method
Measure the resistance of the sensor with a multimeter (normal value: 0.7-1.2kΩ).
Check for short circuits or open circuits in the wiring.
Emergency response
Immediately turn off high-power devices such as air conditioners.
Avoid sudden acceleration and drive smoothly to the repair point.
Replacement suggestion
Give priority to original factory parts (with an error rate lower than 0.5%).
When installing, strictly follow the torque standard (usually 8-10N·m).
The rotational speed sensor, with a magnetoresistor as the sensing element, is a new type of rotational speed sensor. The core component adopts a magnetoresistor as the detection element, and then through a brand-new signal processing circuit, the noise is reduced and the function is more complete. By comparing the output waveforms with those of other types of gear speed sensors, the measured speed error is extremely small and the linear characteristics are highly consistent. The object of induction is magnetic or ferromagnetic materials, such as magnetic steel, iron and electrical steel, etc. When the object under test has protrusions (or depressions) of magnetic or ferromagnetic materials, as the object rotates, the sensor outputs a pulse signal related to the rotation frequency, achieving the purpose of speed measurement or displacement detection.
The gear speed sensor has the following features:
High sensitivity, high reliability, long service life and long trigger distance
The signal trigger is made of iron (soft) magnetic material
It can achieve long-distance transportation and has strong anti-electromagnetic interference ability
Good impact resistance and seismic resistance.
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