What is the abbreviation for air flow meter?

Hello, the abbreviation for Air Flow Meter is MAF

Hello, the English abbreviation of air flow meter is MAF

The science of studying the quality change of things, the law of mutual change of quality is the basic law of the development of the relationship between thingsTherefore, the measurement object is no longer limited to pipeline liquids in the traditional sense, and there is a problem of flow measurement wherever it is necessary to grasp the quantity change.

Flow, pressure and temperature are listed as the three major detection parameters. For a certain fluid, the energy possessed by knowing these three parameters can be calculated, and these three parameters must be checked in the measurement of energy conversion. Energy conversion is the basis of all production processes and scientific experiments, so flow is the most widely used as pressure and temperature instruments.

Energy metering. Energy is divided into primary energy (coal, coal, coalbed methane, liquefied petroleum gas and natural gas), secondary energy (electricity, coke, artificial gas, refined oil, liquefied petroleum gas, steam) and energy-carrying working fluid (compressed air, oxygen, nitrogen, hydrogen, water). Energy metering is an important means to scientifically manage energy, achieve energy saving and consumption reduction, and improve economic benefits.

Flow meters are an important part of energy metering, and water, artificial gas, natural gas, steam and oil are commonly used in these energy sources in an extremely large number of flow meters, which are indispensable tools for energy management and economic accounting.

The function of an air flow meter is to convert the intake air flow into an electrical signal.

The advantage of air flow meters is that the pressure loss is very small and the flow range can be measured. The ratio of the maximum flow rate to the minimum flow rate of the air flow meter is generally more than 20:1, the applicable industrial pipe diameter range is wide, up to 3m, the output signal and the measured flow rate are linear, the accuracy is high, and the fluid flow rate of acid, alkali, salt solution, water, sewage, corrosive liquid, mud and slurry can be measured with a conductivity of 1 s cm.

The principle of the air flow meter:

During the use of an air flow meter, the gas flow is passed through the flow meter to propel the turbine blades to rotate. The number of revolutions of the impeller is directly proportional to the volume of gas passing through the air flow meter. A specially designed patented deflector is installed at the inlet of the flow meter to accelerate the flow of air into the flow meter as the flow rate increases.

The deflector frame is designed to eliminate any potential fluid disturbances such as eddy or asymmetrical flow.

The push force on the turbine blades is also increased at the same time. This ensures that the flow meter is metered with high accuracy within the allowable error range, even in the case of small flow rates. The air flow acting on the turbine blades is axial, and the turbine is mounted on the main drive shaft, which is equipped with high-strength ball bearings.

After the gas passes through the turbine blades, the rotation of the turbine blades is decelerated by the gear set.

The above content reference:

The air flow meter of the car is an important control element of the engine, which is mainly used to detect the air inhaled by the engine, and calculate the air flow rate and transmit it to the engine computer in time, and the computer will send a finger to the fuel injector for fuel injection according to the obtained data.

Air flow meters are used in very old engines (M20, M30, M40), and most engines now use air quality meters. Both air flow meters and air quality meters are called "air meters". Let's talk about the role of an air quality meter.

The air gauge is installed between the air filter and the throttle valve and is used to measure the air quality drawn into the engine, and based on the measured data, it is provided to the DME to calculate the amount of fuel injected to obtain a suitable air/fuel ratio.

At present, the working principle of the common air gauge is: DME relay provides working voltage to the air gauge and heats it to 180 degrees higher than the outside temperature, and when the air flows through, it will cool down the air gauge (the more air, the greater the cooling), so that the resistance value of the air gauge will change accordingly, affecting the current applied to the air gauge. The air meter provides a feedback voltage of 1 5 volts, and the DME uses the feedback voltage to know the amount of air intake and adjust the fuel injection.

The gas flow meter unit is CFM

CFM (cubic feet per minute) is a unit of flow, cubic feet per minute, which refers to the volume of air that the filter passes through per unit of time.

1cfm=。

The volume of air flow through which the filter passes through a unit time is generally expressed in M3 h air volume units in China, and in foreign countries, it is also expressed in the British air volume unit CFM (cubic foot per minute), that is, FT3 min cubic foot minutes, and the two are converted to: 1cfm.

Gas Flow Meter Principle:

Thermal gas mass flow meters use the principle of thermal diffusion, which is a technology with excellent performance and high reliability under harsh conditions. A typical sensing element consists of two thermal resistance (platinum RTDs), a velocity sensor and a temperature sensor that automatically compensates for changes in gas temperature.

When two RTDs are placed in a medium, the velocity sensor is heated to a constant temperature above the ambient temperature. Another temperature sensor is used to sense the temperature of the medium. The mass flow of gas through the velocity sensor is calculated by the amount of heat transferred by the sensing element.

As the gas velocity increases, the amount of heat taken away by the medium increases. This lowers the temperature of the sensor. In order to keep the temperature constant, the operating current through the sensor must be increased, and the magnitude of this increased current is proportional to the flow rate of the medium.

1.Basic Structure of Air Flow Meter 1Flow plate air flow meter (moving plate type) The flow plate air flow meter is mainly composed of a shell, a flow plate, a temperature sensor, a potentiometer, a micro-motion opening of the oil pump, and a buffer plate.

2.**、Thermal Film Air Flow Meter (LH-AFS) It is made up of 4 thermistors.

2.How the Air Flow Meter Works 1Flow plate type air flow meter (moving plate type) working principle The interaction between the air flow moment m and the spring force n.

Thus, the flow plate works in sync with the throttle. m>n, the plate is open, there is more air, and there is more fuel injection; m Fixed opening, the amount of fuel injected remains unchanged.

The function of the air flow meter is to convert the inhaled air flow into an electrical signal.

The advantage of air flow meters is that the pressure loss is very small and the flow range can be measured. The ratio of the maximum flow rate to the minimum flow rate of the air flow meter is generally more than 20:1, the applicable industrial pipe diameter range is wide, up to 3m, the output signal and the measured flow rate are linear, the accuracy is high, and the fluid flow rate of acid, alkali, salt solution, water, sewage, corrosive liquid, mud and slurry can be measured with a conductivity of 1 s cm.

However, air flow meters cannot measure the flow of gases, vapors, and purified water.

The function of the air flow meter is simply to detect the air intake in the air inlet and transmit it to the ECU in the form of a voltage signal, and then the ECU controls the fuel injection volume of the injector by calculating to achieve the best air-fuel ratio of the mixture into the cylinder for combustion.

The function of the air flow meter is to convert the inhaled air flow into an electrical signal.

The advantage of air flow meters is that the pressure loss is very small and the flow range can be measured. The ratio of the maximum flow rate to the minimum flow rate of the air flow meter is generally more than 20:1, the applicable industrial pipe diameter range is wide, up to 3m, the output signal and the measured flow rate are linear, the accuracy is high, and the fluid flow rate of acid, alkali, salt solution, water, sewage, corrosive liquid, mud and slurry can be measured with a conductivity of 1 s cm.

However, air flow meters cannot measure the flow of gases, vapors, and purified water.

Air flow meters can be broadly divided into the following categories.

1. The vane air flow meter has a simple structure and high reliability, but it has a large volume and large inlet resistance, and the response is slow.

2. The Carmen vortex air flow meter is mainly when a cylindrical or triangular object is placed in the fluid, two columns of rotation in the downstream will be produced in opposite directions, and vortices will appear alternately.

3. The ultrasonic Kármán vortex air flowmeter is mainly installed on both sides of the downstream pipeline of the Kármán vortex generator, and the ultrasonic emission probe and the receiving probe are relatively installed. Due to the effect of Kármán vortex on air density, the time from the emitting probe to the receiving probe of ultrasonic waves is different from that of no vortex later. This phase signal is then processed to obtain a vortex pulse signal.

4. Optical Kármán vortex air flow meter, in the process of generating Kármán vortex, the air pressure on both sides of the vortex generator will change, when the light of the light-emitting diode is illuminated on the vibrating metal foil, the phototransistor receives the light modulated by the vortex, and then outputs the frequency signal representing the air flow.

1. Vane air flow meter.

The structure of the air flow meter is simple and the reliability is high; However, the intake resistance is large, the response is slower and the volume is larger.

2. Carmen vortex air flow meter.

The so-called Kármán vortex refers to the vortex that occurs alternately in two columns of rotation in opposite directions downstream of the fluid when a cylindrical or triangular object is placed in a fluid.

3. Optical Carmen vortex air flowmeter.

During the creation of the Kármán vortex, the air pressure on both sides of the vortex generator changes. When the light of the light-emitting diode is illuminated on the vibrating metal foil, the reflected light on the metal foil received by the phototransistor is the light modulated by the vortex, and its output is demodulated to obtain a frequency signal representing the air flow.

4. Ultrasonic Carmen vortex air flowmeter.

Ultrasonic emission probes and receiver probes are mounted opposite each other on both sides of the downstream tubing of the Kármán eddy current generator. Due to the influence of Kármán vortex on air density, the ultrasonic wave will be sent from the transmitting probe to the receiving probe later than the non-vortex probe, resulting in phase difference. By processing this phase signal, a vortex pulse signal can be obtained.

5. ** type air flow meter.

Working principleWhen there is no air flow, the bridge is in equilibrium, and the control circuit outputs a certain heating current to the first resistance rh; When there is air flowing, because the heat of RH is absorbed by the air and becomes cold, its resistance value changes, the bridge is out of balance, if the temperature difference between the resistance and the inhaled air is kept unchanged and a certain value, it is necessary to increase the current flow through the resistance IH. Therefore, the current IH is a function of the air quality flow.

6. Hot film air flow meter.

The working principle of the hot film air flow meter is similar to that of the ** type air flow meter, which works with the Wheatstone bridge. The difference is that the hot film type does not use platinum wire as the first grade, but makes the first resistor, compensation resistor and bridge resistor on the same ceramic substrate with a thick film process.

7. Target air flow meter.

When the air flows in the measuring tube, the pressure difference between its own kinetic energy and the target produces a force on the target, which causes a slight displacement of the target piece, and the magnitude of the force is proportional to the square of the flow rate of the medium.

An air flow meter is an appliance that converts the flow of inhaled air into an electrical signal. The advantage of air flow meters is that the pressure loss is very small and the flow range can be measured.

The ratio of the maximum flow rate to the minimum flow rate of the air flow meter is generally more than 20:1, the applicable industrial pipe diameter range is wide, up to 3m, the output signal and the measured flow rate are linear, the accuracy is high, and the fluid flow rate of acid, alkali, salt solution, water, sewage, corrosive liquid, mud and slurry can be measured with a conductivity of 1 s cm. However, air flow meters cannot measure the flow of gases, vapors, and purified water.

There are four main types of air flow meters:

1. Leaf type air flowmeter: it is mainly a flowmeter for flow measurement according to Faraday's law of electromagnetic induction;

2. Carmen vortex air flow meter: mainly when a cylindrical or triangular object is placed in the fluid, two columns of vortices will be generated in the downstream of this object in opposite directions and alternately;

3. ** type air flow meter: place a section of heating platinum in the air channel, because the heat is absorbed by the air, the heating element itself cools down, and the more air circulated, the faster the heating element cools down; ECM changes the current supplied to the heating element according to the temperature of the inlet air and the amount of air intake, maintains a certain temperature difference between the temperature of the air and the heating element, and senses the flow of air by measuring the current of the heating element.

4. Hot film air flow meter: This is similar to the ** air flow meter, which uses the Wheatstone bridge;

Among them, the hot film air flow meter does not use platinum wire as the first grade, but the first resistance, compensation resistance and bridge resistance are made on the same ceramic substrate with a thick film process; In addition, hot-wire, hot-film, and thermally resistive air flow sensors have a fast response time and can reflect changes in air flow in milliseconds.

Especially in Japanese cars, ** type air flow meters are very common.

Classification of air flow meters:

1. Mass air flowmeter MAF, referred to as L-type;

2. Volumetric air flowmeter MAP, referred to as D type.

Leaf Air Flow Meter Carmen Vortex Air Flow Meter ** Air Flow Meter Thermal Film Air Flow Meter.

Measuring core air flow meter.