Automotive Sensor Classification

Blog | news | Mar 04,2023

The definition of a sensor

A sensor is a detection device that senses the information being measured. And it can convert the perceived information into electrical signals or other required forms of information output according to certain rules. To meet the requirements of information transmission, processing, storage, display, recording, and control.

It usually consists of sensitive components, conversion components, signal conditioning, conversion circuits, and other auxiliary components.

The sensitive element accepts the measured value and outputs other quantities that have a certain relationship with the measured value;
The conversion element converts other quantities from the sensitive element into an electrical signal suitable for transmission and measurement;
Electrical signals are converted into useful electrical signals that can be displayed, recorded, processed, and controlled through signal conditioning and conversion circuits;
Finally, the useful electrical signal is transmitted to other devices for communication.

The composition of the sensor:

Sensitive component: a component that directly senses the measured value and outputs a certain physical quantity that has a certain relationship with the measured value.

Conversion element: The core element of the sensor, which takes the output of the sensitive element as input and converts the sensed non-electrical signal into an electrical signal output. The conversion element itself can be used as a stand-alone sensor, called an element sensor.

Conversion circuit: the relevant circuit involved in converting the electrical signal output by the sensing element into a useful electrical signal for processing, control, recording, and display.

Auxiliary Power: Conversion elements and conversion circuits often require auxiliary power.

Automotive sensors are devices that convert non-electrical signals into electrical signals and transmit various working condition information to the vehicle. Automotive sensors can be divided into body perception sensors and environment perception sensors according to the purpose of use.

Automotive sensors

The body perception sensor improves the informatization level of the bicycle itself so that the vehicle has the ability to perceive itself; according to the input to be measured, it is mainly divided into pressure sensors, position sensors, temperature sensors, linear acceleration sensors, angular acceleration sensors, air flow sensors, Gas sensors, from the working principle, most of these sensors use MEMS solutions.

The environmental perception sensor realizes the ability of the bicycle to perceive the external environment, helps the car computer to obtain environmental information and make planning decisions, and provides support for the intelligent driving of the vehicle; the environmental perception sensor is mainly divided into vehicle cameras, ultrasonic radar, millimeter wave radar, laser Radar and infrared radar, etc.

Body perception sensors are all over the body of the car and are widely used in the power system (new energy vehicles are three-electric systems), chassis systems, and body systems to realize the perception of the car’s own information and make decisions and executions. It is the “nerve end” of the car. At present, the development is relatively mature, mainly based on MEMS sensors.

The source of power is one of the main differences between new energy vehicles and traditional fuel vehicles. The electrical and electronic architecture of new energy vehicles mainly uses current-based electromagnetic sensors related to batteries, motors, and electronic controls.

The power system of fuel vehicles mainly uses measurement Pressure, temperature, and gas sensors are the main ones; the demand for electromagnetic sensors is expected to gradually increase with the increase in the penetration rate of new energy vehicles.

According to the different physical quantities to be measured, the body perception sensors can be divided into various types of sensors such as pressure, position, temperature, acceleration, gas, and flow.

Environmental Perception Sensors Environmental Perception Sensors are produced during the evolution of automotive safety technology from passive safety to active safety.

The main function of the perception sensor is to detect and recognize the surrounding environment of the vehicle, which can be regarded as the eyes of the vehicle. Different types of automotive intelligent driving perception systems have different applicable scenarios, limited scenarios, advantages and disadvantages, and costs, and they form a complementary relationship with each other.

Environmental perception sensors capture external information and provide it to the car computer system for planning and decision-making, mainly including laser radar, car camera, millimeter wave radar, ultrasonic radar, etc.

The vehicle’s intelligent driving perception system offers a basic framework to recognize the environment and generate driving instructions. It converts real-world information, such as visual and physical events, into digital signals.

Pressure Sensor

This data is paramount for the advanced assisted driving system – it is used to make prompt and accurate decisions in order for the executive layer to safely drive the car.

Body Sensing: Pressure Sensor

Automotive pressure sensors that convert pressure signals into electrical signals are mainly divided into two types: capacitive and resistive.

A pressure sensor is a device that senses a pressure signal and converts the pressure signal into a usable electrical signal.

Automotive pressure sensors are employed in engines to detect changes in atmospheric pressure and turbocharger increases. According to the various technical standards, they are commonly categorized into two types: resistive pressure sensors and capacitive pressure sensors. These components are often used in the engine’s intake manifold.

pressure, detect the oil pressure of the suspension system, detect the tire pressure in real-time, measure the combustion pressure of the mixture in the cylinder, etc.

Body Sensing: Position Sensors

A position sensor is a device that measures where a component is operating or moving.

There are five main working principles of automotive position sensors:

♦ Hall effect,
♦ Magnetoresistance effect,
♦ Photoelectric,
♦ Capacitive,
♦ Electrothermal.

According to different uses, it can be divided into crankshaft position sensor, throttle position sensor, vehicle height and angle position sensor, liquid level sensor, orientation sensor, seat position sensor, etc.

Body Sensing: Automotive Temperature Sensors

Temperature Sensors: The most widely used temperature sensors on vehicles are thermistor temperature sensors. Automotive temperature sensors convert temperature signals into usable output signals.

According to the working principle, they can be divided into thermistor type, thermocouple type, and thermosensitive ferrite type. Among them, thermistor-type temperature sensors are the most widely used.

According to different application scenarios, thermistor temperature sensors can be divided into intake air temperature sensors, coolant temperature sensors, interior and exterior temperature sensors, evaporator outlet temperature sensors, exhaust temperature sensors, etc.

Body Perception: Automotive Inertial Sensors

Inertial sensors are used to measure changes in the motion of an object within inertial space. These devices work based on whether or not the observed movement is linear.

Inertial sensors are divided into linear acceleration sensors and angular acceleration sensors;
According to the number of measurement axes, they are divided into single-axis, double-axis, and three-axis acceleration sensors.

Combining linear acceleration sensors, angular acceleration sensors and other measuring components can meet the needs of automotive safety control and navigation systems.

Specific applications include automotive airbags, ABS anti-lock braking systems, electronic stability programs (ESP), and electronically controlled suspension systems wait.

Linear acceleration sensor:

A linear acceleration sensor, also known as an acceleration sensor, is a device that measures the inertial force inside the sensor and calculates the acceleration data.

According to the working principle, different acceleration sensors can be divided into AC response type and DC response type.

The sensing mechanism of AC acceleration sensors usually uses piezoelectric elements, which are divided into voltage-output piezoelectric sensors and charge-output piezoelectric sensors;

DC acceleration sensors can be divided into capacitive and piezoresistive according to different sensing technologies.

Angular (acceleration) speed sensor:

An angular acceleration sensor, also known as an angular speed sensor, is essentially a gyroscope.

The gyroscope is an angular motion detection device that uses the momentum moment (generated by the rotation rotor) to detect the angular motion of the sensitive shell relative to the inertial space around one or two axes orthogonal to the rotation axis.

It can be used together with the accelerometer to form an inertial navigation system. A major factor in the accuracy of a navigation system.

Body perception: Airflow sensor

The airflow sensor, also known as the air mass flow meter, can be used to detect the intake air volume of the engine and is one of the most important sensors of the EFI engine.

The airflow sensor is usually installed on the intake pipe, which converts the intake air quantity signal into an electrical signal and transmits it to the ECU for the ECU to determine the fuel injection quantity and ignition time.

To electronically adjust the gasoline injection engine so that it can basically obtain the best concentration of the mixture under various rotation conditions, it is necessary to measure the amount of air inhaled into the engine at every moment, which is the key for the ECU to calculate (adjust) the fuel injection quantity in accordance with.

If the airflow sensor or the circuit fails, the ECU cannot get a good intake signal, and the fuel injection volume cannot be adjusted properly, which will cause the mixture to be too rich or too lean, make the engine rotate abnormally, and even cause parts to be damaged.

Airflow sensors are divided into the volumetric type and mass type, among which the volumetric type includes vane type, Karman vortex type, and measuring core type, and the mass type includes hot wire type and thermal mode.

Body perception: Gas sensors

A gas sensor is a device that detects information such as the type and concentration of gas.

♦ Gas sensors can be divided into
♦ Semiconductor gas sensors,
♦ Solid electrolyte gas sensors,
♦ Catalytic combustion gas sensors,
♦ Electrochemical gas sensors,
♦ Optical gas sensors, etc.

The different technical principles are divided into

♦ Oxygen sensors,
♦ NOX sensors,
♦ Lean mixture sensors,
♦ Smoke concentration sensors,
♦ Diesel engine smoke sensors.

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