Crankshaft sensor_Crankshaft sensor type_Crankshaft sensor role in the car

The Crankshaft Sensor is a bridge for the intelligent development of the automobile. The crankshaft Sensor is also called the Crankshaft Position Sensor. The crankshaft position sensor is one of the most important sensors in the engine electronic control system. It provides the ignition timing (ignition advance angle) and confirmation. The signal at the crankshaft position is used to detect the top dead center of the piston, the crank angle and the engine speed. The structure of the crankshaft position sensor varies from model to model and can be divided into three categories: magnetic pulse type, photoelectric type and Hall type.

And what are the applications and functions of these three types of sensors in the car, the following small series for everyone to unlock.

The structural principle of the crankshaft position sensor:

The number and technical level of crankshaft sensors determine the performance of modern vehicle control systems and provide a strong guarantee for improved vehicle performance. The sensor is the information source of the automotive electronic control system. It is a key component to promote the high-tech, electronic and automation of automobiles. It is also one of the core contents of the research in the field of automotive electronics technology. The sensor can recognize the changes of the outside world and the system itself in time, and measure the temperature, pressure, position, speed, volume flow and Other information in real time and accurately, and transmit the information to the computer for processing, thereby realizing the electronic control of each system of the automobile.

First, the magnetic induction type:

Magnetic Inductive Sensor Working Principle: The magnetic sensor is based on the principle of electromagnetic sensor. It is measured by magnetoelectric interaction and converted into a sensor that induces electromotive force. It is also called inductive transmitter and electric sensor. The base type of this type of sensor is a Speed Sensor that measures line speed directly. Because there is an intrinsic connection between velocity and displacement and acceleration, that is, there is an integral or differential relationship between them. Therefore, if an integrating circuit is connected to the measuring circuit of the induced electromotive force, its output is proportional to the displacement; if a differential circuit is connected in the measuring circuit, its output is proportional to the acceleration of the motion. In this way, such magnetic sensors can be used to measure the displacement or acceleration of motion. Magnetoelectric sensors, sometimes referred to as electric or inductive sensors, are only suitable for dynamic measurements. Because it has a large output power, the matching circuit is relatively simple; the zero position and performance are stable; the operating frequency band is generally 10 to 1000 Hz. The magnetoelectric sensor has a bidirectional conversion characteristic, and the reverse conversion effect can be used to form a force (moment) generator and an electromagnetic exciter. According to the law of electromagnetic induction, when the W匝 coil moves in the constant magnetic field, the magnetic flux passing through the coil is Φ, and the induced potential e in the coil has the following relationship with the flux change rate dΦ/dt: E=-w (dΦ/dt)

According to this principle, it is possible to design two types of structures, a variable magnetic formula and a constant magnetic formula, to constitute a magnetoelectric sensor that measures linear velocity or angular velocity. There are two kinds of such structures, 1. Variable magnetic structure: (a) Rotary type (variable magnetic); (b) Translating type (variable air gap) 2. Constant magnetic general structure: (a) Moving coil type; (b) Moving iron type.

At the same time, the crankshaft position sensor is also one of the most important sensors in the engine electronic control system. It provides the ignition timing (ignition advance angle) and the signal for confirming the crankshaft position for detecting the top dead center of the piston, the crank angle and the engine speed.

The magnetoelectric induction speed sensor and the crankshaft position sensor are installed in the distributor in upper and lower layers. The sensor consists of a permanent magnet induction detection coil and a rotor (a timing rotor and a speed rotor) that rotates with the distributor shaft. The timing rotor has one, two or four teeth and other forms, and the rotating rotor has 24 teeth. The permanent magnet induction detecting coil is fixed on the distributor body. If the speed sensor signal and the crankshaft position sensor signal are known, as well as the operating sequence of each cylinder, the crankshaft position of each cylinder can be known. The rotor signal disc of the magnetoelectric induction speed sensor and the crank position sensor can also be mounted on the crankshaft or camshaft.

two. Hall effect type:

In automotive ignition systems, there is an ignition system that triggers with a Hall signal generator, the signal generator of the system. It is made by applying the Hall effect principle, so it is also called Hall-type electronic ignition system. The Hall signal generator works by using the Hall effect of the Hall element, that is, by using the Hall generator only when the DC voltage and the magnetic field act simultaneously, a voltage signal is generated in the generator, and this signal causes the engine to generate an ignition signal.

The Hall sensor is a magnetic field sensor fabricated according to the Hall effect. The Hall effect is a kind of magnetoelectric effect, which was discovered by Hall in 1879 when studying the conductive mechanism of metals. Later, it was found that semiconductors, conductive fluids, etc. also have this effect, and the Hall effect of semiconductors is much stronger than that of metals. Various Hall elements made by this phenomenon are widely used in industrial automation technology, detection technology, information processing, etc. aspect.

Used in automotive engines:

a signal sensor in the distributor;

(2) The engine speed and crank angle sensor and the ignition pulse trigger are used in the distributorless ignition system;

(3) making various switches;

(4) for automobile speedometers and odometers;

(5) as a speed sensor in an anti-lock braking system (ABS);

(6) Position sensor and current commutator in the brushless DC motor for vehicle;

(7) for various liquid detectors;

(8) For current detection of various electrical loads and diagnostics of their working conditions;

(9) In the OBD-II type on-board diagnostic device, the engine is turned off;

(10) A speed sensor in an automatic braking system (instead of a hand brake);

(11) A current controller for battery charging. It can also be used in navigation systems, transmission control, automatic control of automobile production lines, and inspection of flexible road surfaces.

three. Photoelectric type:

The photoelectric sensor converts the measured change into a change of the optical signal, and then controls the light signal into an electrical signal by means of the photoelectric element. Such as photoelectric switches, light-sensitive resistors, photodiodes, photovoltaic cells, optical fibers, etc. Photoelectric sensors are widely used in the field of detection and control. They are sensors that use photoelectric components as detection elements. They have the advantages of fast response, high precision, non-contact, etc., and they have many parameters to measure, simple structure and flexible form. This article lists the application of photoelectric sensor technology in some fields. It also expounds the current development status and development trend of sensor technology.

The role of photoelectricity in automotive engines:

The role of photoelectric applications and automobiles is divided into the following four races.

3.1 photoelectric car Height Sensor

The active suspension system can control the suspension actuator by the electronic control unit ECU according to the vehicle height, vehicle speed, steering angle and speed, braking and other signals, so as to make the suspension stiffness, the damping force of the damper and the height of the vehicle. Change to make the car have good ride comfort and operational stability.

3.2 photoelectric steering sensor

The photoelectric steering sensor is mounted on the steering shaft tube and is used to detect the intermediate position, the direction of rotation, the angle of rotation and the speed of rotation of the steering wheel. In the electronic control suspension, the electronic control device determines the lateral force of the vehicle when steering according to the Vehicle Speed Sensor signal and the steering sensor signal to control the roll of the vehicle body.

3.3 photoelectric light sensor

The photoelectric light sensor uses cadmium sulfide (CdS) as a semiconductor component. When the light is irradiated with cadmium sulfide (CdS), the resistance value changes accordingly (the resistance value is large when the surrounding environment is dark, and the resistance value becomes small when it is bright), and the ambient light can be illuminated. The change is converted to a change in resistance value and is input to the controller in the form of an electrical signal. The photoelectric steering sensor is mounted on the steering shaft tube and is used to detect the intermediate position, the direction of rotation, the angle of rotation and the speed of rotation of the steering wheel. In the electronic control suspension, the electronic control device determines the lateral force of the vehicle when steering according to the vehicle speed sensor signal and the steering sensor signal to control the roll of the vehicle body.

3.4 Photoelectric speed sensor

Photoelectric speed sensors are used in digital speedometers, consisting of light-emitting diodes, phototransistors, and visors mounted on the speedometer drive shaft. The digital speedometer is mainly composed of a fluorescent tube, an electronic control unit, an integrated circuit IC, and the like. The pulse signal output from the vehicle speed sensor is transmitted to the speedometer, and the speed is displayed on the fluorescent display screen, and the signal is input to the odometer, fuel gauge, thermometer, and the like.