The automobile instrument is composed of various instruments and indicators, especially the driver's warning light alarm, etc., to provide the driver with the required vehicle operating parameter information. According to the working principle of the automobile instrument, it can be roughly divided into three generations. The first generation of automotive instrumentation is a mechanical movement watch; the second generation of automotive instrumentation is called an electrical instrumentation; the third generation is an all-digital automotive instrumentation, which is a networked, intelligent instrument with more powerful functions and display content. More rich, wire harness links are much simpler. The following Xiaji network Xiaobian to introduce to you the role of the car instrument, the correct use of the method, the meaning of the color of the light, the classification of the light, the principle, fault diagnosis.
The role of the car instrument, the correct use of the content, etc.
The role of car instruments
1. Display some parameter values of the vehicle, such as vehicle speed, engine speed, fuel quantity, water temperature, etc.
2. The indication indicates whether the vehicle has a fault, or a faulty part, such as an engine fault light such as an engine, ABS, ESP, or automatic box, and the LCD screen displays a fault;
3. Display some operations of the vehicle, such as turn signals, high beam lights, gear positions, etc.
4. Prompt the vehicle for regular maintenance.
Correct use of car instruments
1. Wipe the surface of each instrument frequently. On the one hand, it prevents dust and oil from invading the inside of the instrument and damages the watch core. On the other hand, it is also convenient to observe the dynamics of the instrument pointer.
2. Master the relationship between the performance of each meter and the status of the meter indication and the working status of the engine, in order to judge the working condition of the engine according to the status of the meter, and find the fault location and cause.
3. When the engine starts, it is necessary to observe the dynamics of each instrument, find abnormalities, and deal with them in time; during engine operation and car driving, the dynamics of each instrument should also be observed frequently in order to grasp the working conditions of each related system.
4. Meters with different voltage values shall not be substituted for each other except the ammeter to avoid damage to the instrument.
5. The sensor performance of electrothermal and electromagnetic instruments is quite different. For example, the variable resistance sensor of the electrothermal fuel gauge has a resistance value that decreases with the oil level of the fuel tank, and the variable resistance sensor of the electromagnetic fuel gauge. The resistance value change is reversed; the variable resistance value of the electrothermal oil pressure gauge sensor decreases with the increase of the oil pressure, and the variable resistance value of the electromagnetic oil pressure gauge changes exactly the opposite; the electrothermal water temperature sensor The thermistor has a resistance value of 220 ohms at a water temperature of 50 ° C and a temperature of 20 ohms at a water temperature of 115 ° C. The thermistor of the electromagnetic water temperature sensor has a high resistance value at a water temperature of 100 ° C. The temperature continues. The increase in the resistance value is significantly reduced. Therefore, the electrothermal and electromagnetic instruments and their sensors should be used together and should not be used interchangeably or separately.
6. The water temperature gauge sensor must be well grounded. The wires of the sensor must not be grounded or short-circuited to avoid damage to the water temperature gauge.
7. When installing the oil pressure sensor, the “↑” mark should be turned upwards, otherwise the accuracy of the oil pressure gauge indication will be reduced.
8. The lower terminal of the electromagnetic fuel gauge should be connected to the sensor, and the upper terminal should be connected to the ignition switch. Otherwise, the pointer always points to "0".
9. The movement of the float in the fuel tank should be flexible; the fuel tank and fuel gauge sensor grounding should be reliable. If the grounding is bad, the pointer will always point to the “0” end.
10. When charging the fuel gauge system, the sensor should not be taken out of the fuel tank to prevent the fuel tank from igniting due to the sliding of its variable resistance, causing the fuel tank to ignite or even explode.
11. When the voltage regulator is installed in the instrument circuit, the outer casing should be reliably grounded. When the voltage regulator is damaged, the instrument cannot be directly connected to the power supply to avoid damage to the instrument.
12. The positive and negative poles of the ammeter cannot be reversed. If the car is grounded at the negative pole, the “-” pole of the ammeter should be connected to the live line of the battery (positive), and the “+” pole should be connected to the live line of the alternator.
13. Before the current meter is connected, the contact surfaces of washers, nuts, bolts, etc. should be sanded and cleaned. When installing the nut, it is best to apply a little clean oil to prevent corrosion and easy to disassemble; the flat insulating gasket should be intact, and the insulating gasket and A flat washer should be placed between the spring washers and securely connected to prevent the hair from being hot due to poor contact and even burning the meter and harness.
14. Regular inspection of electrical instruments. In the absence of testing instruments, it can be compared with standard instruments: the indication error of the ammeter should be less than ±20%; the indication error of the oil pressure gauge should be less than ±10% when the oil pressure is 0.2 MPa. When the oil pressure is 0.5 MPa, it should be less than ±20%.
The meaning of the color of the light on the car instrument
1. Green: function indicator light - prompt function (such as reversing radar, cruise system, power mode switch, shifting indicator light, etc.);
2．yellow: fault warning light and function indicator light - for warning function (such as ABS lamp, engine fault light, traction control indicator, etc.);
3．red: fault warning light - a serious warning (such as oil lamp, seat belt indicator, battery indicator, etc.).
Classification of lights on car meters
It is roughly divided into three categories: indicator class, prompt class, and warning class.
1. Indication class: used to explain some basic conditions of the vehicle, indicating the current working state of the vehicle, which is convenient for understanding the functions and status of the vehicle (such as the lighting system indicator, water temperature indicator, fuel quantity indicator);
2. Prompt class: used to indicate that the current state of the vehicle is not normal or the operation is not correct. (such as seat belt reminder light, door opening reminder light);
3. Warning class: It indicates that the vehicle is faulty and needs to be repaired (such as engine fault light and oil lamp).