With the development of electronic technology and social progress, automotive electronic control systems become more and more popular. The technology of sensors is most crucial in the electronic control system. Now people expect intelligent, multi-functional, miniaturized, integrated sensors. These sensors gradually become essential parts of the car engine.
Nowadays, the car electronic control system, a crucial technical part of the vehicle development, is more and more popular. Engine sensors are essential in the electronic control system. Sensors accurately control and test helpful information such as pressure, air intake, acceleration, position, vibration, speed and temperature of the vehicle system on time, which essentially improves comfort and plays a crucial role in safe driving. We show you the pressure, mass air flow, speed and temperature sensor - four types - to explain the present situation of such vital car parts.
Many parts of the car are under pressure during driving. Pressure sensors test the oil pressure, cylinder pressure, turbo engine boost ratio, atmospheric pressure, negative cylinder pressure, etc. The primary purpose of getting these figures is to ensure routine driving. Pressure sensors convert the pressure of water or gas into an electrical signal. They send the signal to the ECU. The whole process is under control and in monitoring.
There are two types of pressure sensors in the automotive electronic control system: resistive strain gauge pressure sensor and semiconductor piezoresistive effect pressure sensor. The former goes into service at high pressure. The latter goes into service at low pressure. Besides these two, surface acoustic wave sensor (SAW), linear variable differential transformer sensor (LVDT) and capacitive pressure sensor are also practical. SAW has good digital output, high resolution and sensitivity, enough reliability, low power dissipation, light weight and small size. The sensor works stably under high temperatures and tests the pressure of the suction valve. It is an ideal pressure sensor. LVDT has good digital output, poor anti-interference. The capacitive sensor has good adaptability and dynamic response, high input energy. It tests air pressure, liquid pressure and negative pressure. The measurement range is 20-100kPa.
In the electronic control system, the mass air flow sensor tests the amount of air that the engine inhales. The engine speed and the air intake decide the primary ignition advance angle and the fuel quantity. The air intake has a significant impact on the working engine. There are several types of MAF: Kármán vortex, hot wire, membrane, laminar flow elements, etc. MAF sensors generally install between the throttle body and the air filter. The engine tests the air intake by the velocity density method and the mass flow method. The latter is more popular now. In this method, the air flow meter tests air intake directly. The calculation standard is the ratio of the measured air flow to the engine speed.
The wheel speed sensor is typical of all kinds. It tests the wheel speed, then deduces the driving speed. The engine speed and the air intake decide the primary ignition advance angle and the fuel quantity. The engine speed affects the working engine. The practical wheel speed sensors are semiconductor magnetic transistor, optical, reed switch, Hall Effect type, magneto-resistive, etc. The metrics are usually measured with deviation at the speed of more than 100km/h. In this condition, the non-contact photoelectric speed sensor goes into service. This type of sensor has high accuracy and minor errors.
Temperature sensors test the catalytic temperature, fuel temperature, cooling water temperature, intake gas temperature, engine temperature, etc. There are three practical temperature sensors: thermocouple resistance, thermistor and wire-wound resistance. The thermocouple resistance sensor has a wide range of temperature measurements. The sensor is highly accurate, but the cold end treatment should work with the magnifying glass. The thermistor sensor has good response and high sensitivity, but it has a low adaptation temperature and poor linearity. The wire-wound resistive sensor has high accuracy but poor response. Commercialized temperature sensors are metal or semiconductor membrane air temperature sensor, ferrite sensor and thermistor sensor.
In the modern world, people pay attention to functionality, energy efficiency, environmental protection and safety when they buy cars. These needs are constantly increasing. As a result, the electronic control system is widely popular. The future development direction of this electronic facility is intelligent, multi-functional, miniaturized and integrated. The development of ECU leads to the continuous progress of sensors. It is necessary to develop new sensors with low cost, high reliability and accuracy.
Materials are essential for sensors. We want to produce high-performing sensors with complex materials. In recent years, magnetic, intelligent, ceramic, semiconductor sensitive and synthetic atomic molecular materials are more popular. One-dimensional, single-crystal materials transfer to composite, crystal, and multi-crystal materials. New low-cost, high-performing materials with acute effects should be used in the future.
Intelligent sensors use the microprocessing technology, so they have information processing and testing functions. Intelligent sensors generally integrate a series of peripheral circuits such as signal drive loops, processing and detection on a single chip. They have new functions such as self-adaptation, self-diagnosis, logic judgment and data processing. These sensors send the processed and analog signal and carry out self-correction for time drift, non-linearity and temperature drift of the information, signal amplification, and processing. They have strong resistance to electromagnetic interference, which ensures the quality of the sensor signal, provides high accuracy. Intelligent sensors are easy to use. They have small size, high performance and versatility.
With the field of sensors is expanding, the assembly technology of semiconductors, precision processing, lithography, diffusion, vapor deposition is crucial. The single component and single function converts to the multi-functional, integrated direction. The basis for multi-functionality is integration. The semiconductor processing technology integrates conversion elements, information processing, power circuit elements, and sensitive elements on a single chip.
The miniaturization of sensors integrates micron-level data processing devices, signal conditioners and sensitive components in a single chip by micromachining technology. Miniaturized sensors have good integration, low price and small size, so they are more accurate. Now the practical miniaturized sensors test biological, chemical, thermal, magnetic and mechanical quantities. They have good market potential.
The core of the automotive electronic control systems is the sensor technology, which is constantly developing in intelligence, multi-functionality, miniaturization and integration. High-tech automotive sensors have a broad prospect.