Pressure sensor formation effect
Release date: July 6, 2019
Sensor is a kind of detection device, which is divided into many kinds, forming a sensor family. The most widely used sensor is pressure sensor, which can be seen in almost all industries. Sensor is the main way to obtain information in the field of nature and production. The sensor is a kind of detection device, which can sense the measured part and convert it into usable signal according to a certain rule. The sensor is a kind of detection device, which can sense the measured information and transform the detected information into electrical signal or other required information output according to certain rules, so as to meet the requirements of information transmission, processing, storage, display, recording and control requirement. It is usually composed of sensitive elements and conversion elements. Sensor is the first link to realize automatic detection and automatic control, and it is also an indispensable medium in many links.
The output characteristics of the pressure sensor's intake pressure: the D-type injection system (speed density type) is used to detect the intake air volume in the EFI engine. The air intake pressure sensor is not directly detected as the intake flow sensor, but indirect detection. At the same time, it is also affected by many factors. Therefore, in the inspection and maintenance, there are many different prices of the pressure sensor which are different from the air flow sensor, and the faults produced have its particularity. When the engine works, with the change of throttle opening, the vacuum degree, absolute pressure and output signal characteristic curve in the intake manifold change. But what is the relationship between them? Is the output characteristic curve positive or negative? This problem is often difficult to understand, so that some maintenance personnel have a feeling of "uncertainty" in their work. The absolute and pressure in the intake manifold behind the throttle is detected in the D-type injection system.
The rear of the throttle reflects both vacuum and absolute pressure. Therefore, some people think that vacuum and absolute pressure are the same concept. In fact, this understanding is one-sided. Under the condition of constant atmospheric pressure (the standard atmospheric pressure is 101.3kPa), the higher the vacuum degree in the manifold, the lower the absolute pressure in the manifold. The vacuum degree is equal to the difference of atmospheric pressure minus absolute pressure in manifold. The higher the absolute pressure in the manifold, the lower the vacuum in the manifold. The absolute pressure in the manifold is equal to the difference between the atmospheric pressure outside the manifold minus the vacuum degree. That is, atmospheric pressure is equal to the sum of vacuum and absolute pressure. After understanding the relationship among atmospheric pressure, vacuum degree and absolute pressure, the output characteristics of intake pressure sensor are clear.
When the engine is working, the smaller the throttle opening is, the greater the vacuum in the intake manifold is, the smaller the absolute pressure in the manifold and the smaller the output signal voltage. The greater the throttle opening, the smaller the vacuum degree of the intake manifold, the greater the absolute pressure in the manifold and the greater the output signal voltage. The output signal voltage is inversely proportional to the vacuum in the manifold (negative characteristic) and proportional to the absolute pressure in the manifold (positive characteristic).
Pressure sensor is the most commonly used sensor in industrial practice, which is widely used in various industrial automatic control environment, involving water conservancy and hydropower, railway transportation, intelligent building, production automation, aerospace, military industry, petrochemical, oil well, electric power, ship, machine tool, pipeline and many other industries. The principle and application of some commonly used sensors are briefly introduced. Another medical pressure sensor. And we usually use the pressure sensor is mainly made of piezoelectric effect, such a sensor is also known as piezoelectric sensor. We know that crystals are anisotropic and amorphous are isotropic. When some crystal medium is deformed by mechanical force along a certain direction, it will produce polarization effect; when the mechanical force is removed, it will return to the uncharged state, that is, when under pressure, some crystals may produce electric effect, which is the so-called polarization effect. Scientists have developed pressure sensors based on this effect.