Friends who understand automotive circuit electronics can help

Keys and trip computers, both with wireless devices.

Each key has its own corresponding ID, which has been written into the key's chip.

Will the trip computer actively check whether there is a keyless signal? At a certain distance, the driving computer senses the signal of the key, and then checks whether the ID is consistent with the ID stored by the driving computer? If it is consistent, you can unlock the door. If it is inconsistent, it will not be opened.

The key control is that after the key chip collects the key switch is pressed, the key will send its own ID and switch information together, and the driving computer can perform the corresponding action after receiving it. This is a wireless signal actively emitted by the key, and the strength is relatively large, so it can be at a long distance.

Generally, the distance is tens of meters, and there are very few hundreds of meters.

The smart key control distance of the car is hundreds of meters away. At this time, the operation embodied in the function is to be manually buttoned;

When you are one meter away from the car with the electronic key, you can open the door by pulling the door handle. At this time, the operation embodied by the function is automatically detected by the car.

Therefore, the smart key of the car uses two sets of signal transmission systems. One set for "remote" use (manual operation) and one set for "short-range" use (automatic car test). When the door is closed and it leaves, the smart key is instructed to activate a "proximity" system, such as Bluetooth.

When returning to the car, the car receives a "Bluetooth" signal that allows it to "open the door by pulling the door handle directly".

FYI)

The function of the automobile circuit is that when the current is too large due to load overload and short circuit fault, the protection device automatically disconnects the power supply circuit to prevent the line or electrical equipment from burning out. Related books include "Automotive Circuit Analysis" published by Chinese Renmin University, which focuses on the reading of automobile circuit diagrams, circuit analysis of major electrical systems of automobiles and automotive circuit troubleshooting and diagnosis methods, which has strong practicality.

In order to make the electrical equipment of the automobile work, according to the characteristics of their respective work and the internal connection between each other, the power supply, circuit protection device, control device and electrical equipment and other devices are connected with the wire and the car body, so as to form a path that can make the current flow, and this path becomes the automobile circuit, and the automobile circuit is mainly composed of power supply, circuit protection device, control device, electrical equipment and wire.

There are two power sources installed on the car, namely the battery and the generator. Its function is to ensure that the electrical equipment of the car can be put into normal operation under different circumstances, and the circuit protection device mainly includes fuses, relays, etc., which play a protective role in the circuit. When the current in the circuit exceeds the specified current, the circuit can be cut off to prevent the wire and electrical equipment from being burned out.

In order to make the electrical equipment of the automobile work, according to their respective working characteristics and the internal relationship between each other, the power supply, circuit protection device, control device and electrical equipment and other devices should be connected with the wire and the car body to form a path that can make the current flow, which is called the automobile circuit.

Circuit protection devices, control devices, electrical equipment, and other devices are connected to form a path that allows current to flow, and this path is called an automobile circuit.

Without professional training, it is difficult for ordinary people to understand. The automotive circuit system is still very complex, and unauthorized maintenance without understanding will seriously damage the car.

In the car, often a wiring harness is wrapped with more than a dozen or even dozens of wires, dense and difficult to distinguish their direction, plus electricity is invisible and intangible, so the car circuit is a very complex thing for many people. But everything has its regularity, and automotive circuits are no exception.

Generally, household electricity is used for alternating current, and the parallel circuit of the two-wire system is implemented, and the electrical appliances have at least two external power cords. From the point of view of the automobile circuit, the negative electrode wire (return line) drawn from the load (electrical appliance) should be directly connected to the negative terminal post of the battery, if such wiring method is adopted, then the wire connected to the negative terminal post of the battery will be as many as hundreds. In order to avoid this, the designers used the metal frame of the car body as the negative pole of the circuit, such as the girder.

Therefore, the automobile circuit is significantly different from the general household electricity: the automobile circuit is all direct current, the parallel circuit of the single-wire system is implemented, and the electrical appliances only need to have an external power cord.

Both the negative and load terminals of the battery are connected to a metal frame, which is called "grounding". In this way, the negative wire drawn from the load can be connected nearby, and the current flows back to the negative wire of the battery through the metal frame. With the increasing application of non-metallic materials such as plastic parts in automobiles, many cars now use public grounding network harnesses to ensure the reliability of grounding, that is, the negative wire of the load is connected to the grounding network harness, and the grounding network harness is connected to the negative electrode of the battery.

The automobile circuit implements a single-wire parallel circuit, which is generally viewed, and there are still series, parallel and mixed circuits in the local circuit. In fact, the whole car circuit is composed of various circuits, and each circuit can be listed independently, turning complexity into simplicity. According to the basic use, the whole vehicle circuit can be divided into lighting, signal, instrument, starting, ignition, charging, auxiliary and other circuits.

Each circuit has its own load wire to connect to the control switch or fuse box.

The lighting circuit refers to the circuit system that controls the combination switch, headlamp and small lamp; Signal circuit refers to the circuit system that controls combination switches, turning lights and alarm lights; Instrumentation circuits refer to ignition switches, instrument panels, and sensor circuit systems; The starting circuit refers to the ignition switch, relay, and starter circuit system; Charging circuits refer to the circuit system of regulators, generators, and batteries. The above circuit system is indispensable and constitutes the basic part of the whole vehicle circuit. Auxiliary circuits refer to circuit systems that control wipers, audio, etc.

With the increase of automotive electrical equipment, such as electric seats, electric doors and windows, electric sunroofs, etc., there will be more and more auxiliary circuits.

Automobile circuits are usually composed of power supply circuits, starting circuits, ignition circuits, lighting and light signal device circuits, instrument information system circuits, auxiliary device circuits and electronic control system circuits.

1. Power supply circuit, also known as charging circuit, is a circuit composed of batteries, generators, regulators and charging indication devices, etc., and electric energy distribution (distribution) and circuit protection devices can also be classified into this circuit.

2. The starting circuit is a circuit composed of a starter, a starting relay, a starting switch and a starting protection circuit. The device of starting preheating under low temperature condition and its control circuit can also be included in this circuit.

3. The ignition circuit is a circuit unique to gasoline engine vehicles. It consists of an ignition coil, a distributor, an electronic ignition controller, a spark plug and an ignition switch. The electronic ignition control system controlled by the microcomputer is generally included in the engine electronic control system.

4. The circuit of lighting and light signal device is composed of headlights, fog lights, marker lights, turn signals, brake lights, reversing lights, interior lights and related control relays and switches.

5. The instrument information system circuit is a circuit composed of the instrument and its sensors, various alarm indicators and controllers.

6. The auxiliary device circuit is a circuit composed of various electrical devices set up to improve the safety and comfort of the vehicle. The types of auxiliary electrical devices vary with different models, and the higher the grade of the car, the more complete the auxiliary electrical devices. Generally, it includes windshield wiper and cleaning device, windscreen defrosting (anti-fog) device, air conditioning device, audio device, etc.

The higher-end models are also equipped with electric window lifts, electronically controlled door locks, electric seat adjustments, and electric remote mirrors. Electronically controlled airbags are integrated into the electronic control system.

7. The electronic control system circuit is mainly composed of engine control system (including fuel injection, ignition, emission control, etc.), automatic transmission and constant speed driving control system, brake anti-lock braking system, airbag control system and other circuits.

Automotive Circuit Basics:

1. Power supply circuit: It is composed of battery, generator and voltage regulator and working condition display equipment, etc., and its main task is to supply power to all electrical equipment in the whole car and maintain the stability of power supply voltage.

2. Starting circuit: It is composed of starter, starting relay, starting switch and starting protection device, etc., and its main task is to change the engine from a stationary state to a self-running state.

3. Ignition circuit: composed of distributor, electronic ignition controller, ignition coil, spark plug and ignition switch, etc., its main task is to control and generate enough voltage to break through the spark plug electrode gap, and at the same time send high-voltage electricity to each cylinder spark plug according to the engine working order.

4. Air conditioning control circuit: It is composed of an electromagnetic clutch of an air conditioning compressor, an air conditioning controller, a control switch and a fan control circuit.

5. The instrument circuit is composed of instruments, indicator tables, sensors, various alarms and controllers, etc., and its main task is to control various instrument display information parameters and alarms.

In order to make the electrical equipment of the car work, according to their respective working characteristics and the internal relationship between each other, the power supply, circuit protection device, control device and electrical equipment and other devices should be connected with the wire and the car body to form a path that can make the current flow, which is called the automobile circuit.

As an automotive circuit technician, in the daily circuit maintenance work, it is generally necessary to use appropriate detection methods to diagnose and eliminate faults according to the two basic principles of circuit principle and color line checking, which can be divided into 7 levels.

1.Determine the range of circuit system to be detected according to the fault phenomenon;

2.Understand the circuit principles and circuit characteristics related to faults;

3.Understand the wire diameter, color, marking, function, and circuit direction of the wire related to the layout of the wire harness related to the fault;

4.Select the detection site and the detection point, so that the detection method is selected accordingly;

5.According to the test results, analyze the location and cause of the fault;

6.Troubleshoot according to the actual situation;

7.Summarize the entire maintenance process and accumulate experience and lessons.

The above 7 processes, the theoretical basis of the first 3 layers, and the practical application of the last 4 layers, complement each other and are indispensable.

The basic composition of the automobile circuit is to connect the wires and connectors of electrical equipment such as power supplies, fuses, switches, and electrical appliances in an orderly manner according to certain rules.

Then, the connection points between the various electrical devices can be used as detection points, but these detection points are located differently in the circuit. Then with electrical appliances as the boundary, several circuit concepts can be introduced:

Circuit: Starting from the positive pole of the power supply and returning to the same negative pole of the power supply through the fuse, switch (controller), electrical appliances (load), etc., or from the positive pole of the power supply to the same negative pole of the power supply through the fuse, electrical appliances, switches, etc., it is called a simple "loop". A circuit system is an orderly combination of individual circuits.

To look at the circuit diagram is to see how various electrical equipment constitute circuits and how each circuit is combined in an orderly manner.

Positive circuit: The part of the circuit between the positive pole of the power supply and the electrical appliance is called the "positive circuit".

Negative circuit: The part of the circuit between the consumer and the negative pole of the power supply is called the "negative circuit".

Positive Detection Point: The individual connection points in the positive circuit are called "positive detection points".

Negative Detection Point: The individual connection points in the negative circuit are called "negative detection points".

Forward control: In a circuit, control equipment such as switches and relay contacts are set in the positive circuit, which is called "positive control".

Negative control: The control equipment such as switches and relay contacts is set in the negative circuit, which is called "negative control".

Uplink circuit: The uplink circuit from a point in a loop to the positive end of the power supply is called an "uplink circuit".

Downlink: Going from a point in a loop to the negative end of the power supply is called a "downlink circuit".

This point can be in a positive circuit or in a negative circuit.

An automotive circuit diagram is a structural schematic diagram of the power system on a car. It uses special symbols for electronic technology to mark the connection and distribution of electrical equipment such as power supply, signal lights, stereos, air conditioners, remote locks, and electric windows on automobiles, as well as switches, fuses, relays, etc.

For a car to run, it needs a drivetrain, tires, steering system, engine power, etc., these are all mechanical systems. The headlights, instrument indications, turn signals, high-voltage ignition, power windows, lighting, horns, various electrical appliances, etc., are connected in series to these electricity users and are collectively referred to as the circuits of the car.

In fact, the circuit is actually when the car circuit board is opened, all the wiring is in it, which is the car circuit.

Hello Car circuit is all the operation of the circuit on the car, such as the turn signal, or the front headlights, or about some air conditioning. Or about some engines, it's all some lines.

In order to make the electrical equipment of the automobile work, according to their respective working characteristics and the internal relationship between each other, the power supply, circuit protection device, control device and electrical equipment and other devices should be connected with the wire and the car body to form a path that can make the current flow, which is called the automobile circuit.