Mass air flow sensor. Free Technical Library article

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Mass air flow sensor

Free technical library

Encyclopedia of radio electronics and electrical engineering / Automobile. Electronic fuel injection

Comments on the article

The mass air flow sensor (DMRV 2112-1130010) is a hot-wire type sensor (see photo 1) and outputs a pulse-frequency signal (2-10 kHz) to the controller, which varies in direct proportion to the amount of air passed through it.

The more air passed through the sensor, the higher the frequency of the DMRV signal. Accordingly, the amount of air passed through the sensor depends on the angular position of the throttle valve and the idle speed controller, through which air is supplied to bypass the throttle valve. By the frequency of the DMRV pulses, the controller judges the amount of air entering the engine and, accordingly, regulates the opening time of the fuel injectors, thus ensuring the necessary ratio of air and fuel in the fuel mixture. DMRV includes (see photo 2): 1. Filter retainer ring. 2. Filter. 3. Inlet flange. 4. Sealing rubber ring. 5. Sensor housing. 6. el charge. 7. Thermoelements. 8. Pin connector. 9. Outlet flange. 10. Screws for fastening elements.

Three thermoelements are used in the design of this sensor. One (central) is used to determine the temperature of its environment, and the other two heat the air to a predetermined temperature exceeding the ambient temperature. Mass airflow is determined by measuring the electrical power required to maintain a given temperature rise and converting this power into a pulse-frequency signal. The filter serves to prevent large particles from entering the sensor housing, which can damage the thermocouples. In addition, it acts as an air divider to ensure a uniform air flow. The filter is installed in the inlet flange and fixed with a retaining ring. Sealing rubber rings are installed on both sides of the sensor housing and serve to prevent air leakage. Particular attention should be paid to the O-ring between the sensor body and the outlet flange. If there is air leakage in this place, it may not be taken into account by the system, which will lead to a lean fuel mixture. In this case, it is almost impossible to ensure the optimal operation of the engine, because. the system "January-4" does not provide feedback on the lambda probe. It is rather problematic to identify air leakage without the use of a special multitester.

The DMRV is installed (see photo 3) between the air filter and the air supply hose to the throttle body. To dismantle the DMRV, it is necessary to disconnect the connector with the ignition off, disconnect the air hose and unscrew the two bolts securing the sensor to the air filter. Installation should be carried out in the reverse order of dismantling.

The DMRV resource is not regulated and largely depends on the condition of the air filter. Foreign particles entering the sensor housing can damage it. In the event of malfunctions of the MAF, the error code "33" or "34" is stored in the RAM of the Electric Control Unit, which can be read using the "CHECK ENGINE" lamp in the code reading mode or with a special multi-tester. At the same time, this lamp lights up, and the controller calculates the air flow value from the signals from the throttle position sensor and the crankshaft position sensor.

Symptoms of a malfunctioning DMRV can be an engine stop when shifting gears while the car is moving, engine failures under load and at idle. The "CHECK ENGINE" lamp, at the same time, often does not light up and it can be quite difficult to determine this malfunction with improvised means. When diagnosing a system, it is necessary to carefully study the nature of the engine operation in different modes and compare the response of sensors to a particular symptom. It can be recommended to follow the method of eliminating all possible causes with checking the relevant sensors. It should be borne in mind that the mass air flow sensor is an accurate measuring device and, as practice shows, is "afraid" of blows to the body.

Publication: cxem.net

See other articles Section Automobile. Electronic fuel injection

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

The threat of space debris to the Earth's magnetic field 01.05.2024

More and more often we hear about an increase in the amount of space debris surrounding our planet. However, it is not only active satellites and spacecraft that contribute to this problem, but also debris from old missions. The growing number of satellites launched by companies like SpaceX creates not only opportunities for the development of the Internet, but also serious threats to space security. Experts are now turning their attention to the potential implications for the Earth's magnetic field. Dr. Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics emphasizes that companies are rapidly deploying satellite constellations, and the number of satellites could grow to 100 in the next decade. The rapid development of these cosmic armadas of satellites can lead to contamination of the Earth's plasma environment with dangerous debris and a threat to the stability of the magnetosphere. Metal debris from used rockets can disrupt the ionosphere and magnetosphere. Both of these systems play a key role in protecting the atmosphere and maintaining ... >>

Solidification of bulk substances 30.04.2024

There are quite a few mysteries in the world of science, and one of them is the strange behavior of bulk materials. They may behave like a solid but suddenly turn into a flowing liquid. This phenomenon has attracted the attention of many researchers, and we may finally be getting closer to solving this mystery. Imagine sand in an hourglass. It usually flows freely, but in some cases its particles begin to get stuck, turning from a liquid to a solid. This transition has important implications for many areas, from drug production to construction. Researchers from the USA have attempted to describe this phenomenon and come closer to understanding it. In the study, the scientists conducted simulations in the laboratory using data from bags of polystyrene beads. They found that the vibrations within these sets had specific frequencies, meaning that only certain types of vibrations could travel through the material. Received ... >>

Random news from the Archive

Hyperloop Capsule Speed Record 15.09.2017

On tests of the experimental high-speed transport system Hyperloop, it was possible to reach speeds of up to 355 km / h.

The Hyperloop system places the capsules in an air-exhausted transport tunnel and aims to accelerate them to very high speeds in order to reduce travel times for passengers and cargo.

Enthusiasts of the system claim that the time is not far off when it will be able to reach speeds of up to 1000 km / h.

The idea of the new Hyperloop transport system being developed now was first proposed back in 2013 by the head of Tesla, Elon Musk. This week, in the vicinity of Los Angeles, a special one-mile-long training ground passed the first tests of experimental trains. The fastest train was built by a group of students from Germany.

Once the prototype competition was over, the Hyperloop team allowed the "jump pods" to begin autonomously moving through the test tunnel without human control.

"Push Pods" were formerly used to propel prototypes.

The new record was set by the "jump capsule" in independent movement, even while it has not accelerated. According to Musk, the sight of the capsule moving through the tunnel was "reminiscent of a tugboat race."

Improvement of the route can bring the speed of the capsules up to 500 km/h.

News feed of science and technology, new electronics

We recommend downloading in our Free technical library:

▪ site section Tools and mechanisms for agriculture

▪ magazines Repair of electronic equipment (annual archives)

▪ book amateur kumeter. Akmentynsh A.Ya., 1970

▪ Del's article? Very simply: it is the money of others. Popular expression

▪ article Bonfires and hearths. Basics of safe life

▪ article Network galvanic cell 373, 220/1,5 volts. Encyclopedia of radio electronics and electrical engineering

▪ reference book Service menus of foreign TVs. Book #18

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews