Temperature Sensor manufacturers how to protect the Temperature Sensor insertion rod is not damaged? Mainly from the following points to strictly control the insertion of the sensor insertion rod depth. As the insertion depth increases, the force to protect the insertion rod increases in square times. Therefore, we only need to measure the temperature when the Temperature Sensor into the rod into the isothermal area of the fluid, without having to insert the center point of the pipeline, which will help shorten the length of the thermometer bag cantilever to achieve the effect of reducing the amplitude of its endpoint The In the case of ensuring the necessary sensor insertion bar strength, optimize the selection of the Temperature Sensor insertion rod diameter.
Most of the Temperature Sensors are plug-in type, the Temperature Sensor in front of the insertion rod is its sensing end, once the damage will seriously affect the Temperature Sensor measurement accuracy. So the use of Temperature Sensors will inevitably occur in the phenomenon of rupture, will directly affect the reliable safe operation. So the Temperature Sensor manufacturers to remind you to install must pay attention to the use of methods:
Through the investigation of the phenomenon of the sensor insertion rod rupture, the reasons for finding the rupture of the Temperature Sensor insertion rod are as follows: the Temperature Sensor insertion rod is subjected to high-speed fluid impact, the load is too large, the stress exceeds the limit, Rupture; the Temperature Sensor insertion rod itself processing defects, resulting in stress concentration, likely to cause the insertion rod break; pipe vibration is too large, resulting in Temperature Sensor insertion rod fatigue damage; fluid flow through the Temperature Sensor inserted rod, induced Temperature Sensor insertion rod vibration, That is, the Temperature Sensor insertion rod natural frequency and fluid vortex shedding frequency resonance. This resonance can cause the Temperature Sensor to insert the rod to damage faster, resulting in fracture. In the D-type EFI system, it is installed in the air filter after the inlet hose; in the L-type EFI system, it is installed in the air flow sensor; some intake air Temperature Sensor installed in the intake pressure sensor The Intake air Temperature Sensor inside, is also a negative temperature resistance coefficient of the thermistor. External sealed with epoxy resin. The connection circuit of the intake air Temperature Sensor and ECU is shown on the right.
1. Detect the resistance
The temperature detection method and requirements of the intake air Temperature Sensor are basically the same as those of the coolant Temperature Sensor. When the unit is inspected, place the ignition switch in the OFF position, remove the intake air Temperature Sensor wire connector, and remove the sensor. Heat the air intake Temperature Sensor with hot air, or hot water, and measure the resistance between the two terminals at different temperatures with a multimeter resistance. The measured resistance value is compared with the standard value. If it does not match the standard value, replace the intake air Temperature Sensor.
2, the detection voltage
(1) Detects the supply voltage. Remove the intake air Temperature Sensor harness connector, open the ignition switch, measure the intake air Temperature Sensor power supply voltage, should be 5V.
(2) measurement input. Signal voltage. Set the ignition switch to the ON position and measure the voltage between the THA and E2 of the ECU in the voltage range of the multimeter. The voltage should be in the range of 0.5 - 3.4V (20 ℃). If it is not within the specified range, you should further check the intake air Temperature Sensor connection line is bad or there is open circuit, short circuit fault.
Because when the diameter of the Temperature Sensor insertion rod increases, the table bag force increases linearly, so when selecting the diameter of the bag, it is necessary to reasonably guarantee the strength of the insertion rod, but also as far as possible to offset the resonance danger zone. Change the cross-sectional shape, the surface processed into a structural type, so that the fluid does not produce vortex shedding phenomenon. Strictly control the quality of maintenance, do a good job of sensor insertion rod material inspection, but also do a good job testing, to prevent welding cracks, cracks and other abnormal accidents. When the system is put into operation, avoid the sudden opening of the valve on the pipeline. In the moment when the valve is opened, the Temperature Sensor insertion rod will bear a great unidirectional force, so when the system is just put into operation, slowly open the valve, so that the system pressure gradually increased, as far as possible to reduce the Temperature Sensor insertion rod The difference between the front and the back of the pressure, to avoid the insertion of the rod due to excessive force caused by the insertion rod break occurred.