The function of the automotive temperature sensor
Real-time monitoring of temperature and optimization of vehicle systems
Automotive temperature sensors optimize engine performance, ensure safety and enhance comfort by sensing temperature changes in different parts and transmitting signals to the electronic control unit (ECU). The following is a classification of its main functions:
Engine performance optimization
Youdaoplaceholder0 Coolant temperature sensor (water temperature sensor) : Monitors the coolant temperature of the engine. The ECU adjusts the fuel injection volume, ignition timing and idle control valve accordingly. At low temperatures, it increases the fuel injection volume and starts the ignition earlier; at high temperatures, it prevents detonation.
Youdaoplaceholder0 Intake air temperature sensor : Detects the temperature of the air in the intake pipe, corrects fuel injection and ignition timing to ensure the optimal air-fuel ratio.
Youdaoplaceholder0 Transmission oil temperature sensor : Monitors the temperature of the hydraulic oil in an automatic transmission, assists in shift control and oil pressure regulation to prevent damage from high temperatures.
Safety protection and fault prevention
Youdaoplaceholder0 Exhaust temperature sensor (catalytic temperature sensor) : Monitors the temperature of the catalytic converter and triggers an alarm when abnormally high temperatures occur to prevent catalyst failure.
Youdaoplaceholder0 EGR exhaust gas recirculation temperature sensor : Detects the recirculation exhaust gas temperature (normal 100-400℃) to ensure the normal operation of the EGR valve and reduce nitrogen oxide emissions.
Youdaoplaceholder0 Thermosensitive ferrite temperature sensor : Controls the start and stop of the radiator fan to prevent the coolant from overheating.
Comfort and environmental conditioning
Youdaoplaceholder0 External temperature sensor : Installed on the front bumper or the front panel of the cab, it detects the ambient temperature for the automatic air conditioning ECU to adjust the temperature difference inside the vehicle (for example, the air conditioning is activated to cool down when the outside temperature is 5℃).
Youdaoplaceholder0 Temperature sensor in the vehicle : Located in the ventilation duct of the vehicle, it feeds back temperature data to maintain passenger comfort.
Youdaoplaceholder0 Solar/evaporator temperature sensor : Monitors the temperature at the air conditioning outlet or the surface of the evaporator to intelligently control the operation of the compressor.
Driving Information and Fault diagnosis
Data such as the water temperature sensor will be displayed on the dashboard to alert the driver of abnormal conditions (such as engine overheating).
When a sensor malfunctions, the ECU records the fault code for easy maintenance and diagnosis.
Youdaoplaceholder0 Summary : Automotive temperature sensors, through technologies such as thermistors (like NTC type) and thermocouples, achieve full-chain temperature control from the engine core system to the passenger cabin environment, with efficiency, safety and comfort.
The core manifestations of car temperature sensor failure include: difficult starting, abnormal idle speed, incorrect water temperature display, reduced power and increased fuel consumption, etc. It is necessary to repair or replace the sensor in time to ensure the normal operation of the engine.
Main fault manifestations and solutions
Youdaoplaceholder0 Start-up and idle problems
Youdaoplaceholder0 Difficulty in cold start : When the water temperature sensor malfunctions, the ECU fails to obtain the correct temperature signal, resulting in abnormal fuel injection volume adjustment and imbalance of mixture concentration.
Youdaoplaceholder0 Unstable idle or excessively high : A faulty intake air temperature sensor can cause the ECU to misjudge the fuel injection volume, resulting in a mixture that is too rich/too lean, and subsequently causing idle jitter or abnormal increase in engine speed.
Youdaoplaceholder0 Water temperature gauge and power anomaly
Youdaoplaceholder0 Abnormal water temperature gauge display : The pointer is stuck at the limit value (e.g. 120 ° C) or simply does not respond, which may be due to failure of the thermistor inside the sensor or interruption of signal transmission.
Youdaoplaceholder0 Insufficient engine power : The ECU may activate the protection mechanism upon receiving the wrong water temperature signal, limiting the torque output (e.g. Fault code P003D), resulting in weak acceleration or torque limitation.
Youdaoplaceholder0 Heat dissipation and energy consumption issues
Youdaoplaceholder0 Abnormal operation of cooling fan : The ECU misjudges that the fan keeps working at high temperatures or does not start at all at low temperatures, which may cause the engine to overheat or the air conditioning system to malfunction.
Youdaoplaceholder0 Increased fuel consumption : Incorrect temperature signals cause fuel injection to deviate from the optimal state, incomplete combustion of the mixture, and increase fuel consumption over time.
Youdaoplaceholder0 Other accompanying symptoms
Youdaoplaceholder0 Engine fault light on : Abnormal sensor signal will trigger fault codes (e.g. P01D6, P028F, etc.), need to be checked further by diagnostic instrument.
Youdaoplaceholder0 Emission problem : Black smoke coming out of the exhaust pipe during sudden acceleration, often due to an overly rich mixture caused by a malfunction of the intake temperature sensor.
Suggested maintenance process
Youdaoplaceholder0 Preliminary inspection : Use a multimeter to measure whether the resistance of the sensor conforms to the thermosensitive characteristics (such as resistance decreases as temperature rises) to determine if there is physical damage.
Youdaoplaceholder0 Fault code reading : Obtain specific fault codes (e.g. P003D) through the OBD interface to locate sensor or associated circuit problems.
Youdaoplaceholder0 Component replacement : If the sensor fails, the same model component needs to be replaced (note the difference in plugs between 12V and 5V sensors).
Youdaoplaceholder0 System check : Check the ECU control logic and harness connections to prevent false alarms due to loose connections or short circuits.
In case of engine overheating or a significant drop in power, it is recommended to stop the vehicle immediately and contact professional maintenance personnel to prevent further damage to key components such as the ECU or thermistors.
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