Exhaust analyzer with their own hands. Homemade CO2 gas analyzer for cars. How the injection injection system works

A simple car single-component gas analyzer is designed to measure the content in exhaust gases only carbon oxide Co, mainly uses the method of afterburring not completely burnt components in exhaust gases. Having sinking CO is performed in the measuring chamber of the device using a special heated thread, while changing the temperature of the thread and characterizes the content of CO in the gases. The accuracy of the readings of such a gas analyzer is small and depends in many respects of the content of another component - hydrocarbon CH.

Figure 3. Schematic diagram of two-component gas analyzer on CO and hydrocarbons

1 - probe; 2 ... 4 - filters; 5 - Pump for the supply of exhaust gases; 6 - measuring cuvette (camera); 7 - source of infrared radiation; 8 - synchronous motor; 9 - obturator; 10 - comparative cuvette (camera) CO; 11 - infrared leap-free CO; 12 - membrane capacitor; 13, 16 - amplifiers; 14 - comparative cuvette (chamber) with N N M; 15 - infrared leopper with NN M; 17, 19 - Indicators of hydrocarbons and CO; 18 - measuring cuvette (chamber) with N N M

Determination of the content of harmful substances in the exhaust gases with modern multicomponent gas analyzers for the vehicle is made without the use of chemical reagents, mainly thermal (infrared) measurement method. The method is based on the principle of measuring the absorption of thermal radiation by various components of exhaust gases. The spectrometric unit of the modern gas analyzer works on the principle of partial absorption of the energy of the light flux, which passes through the gas. Molecules of any gas are an oscillatory system that can absorb infrared radiation only in a strictly defined wave range. Thus, if through the flask with the gas to pass a stable infrared stream, then part of it will be absorbed in gas. Moreover, in this case, only the small part of the entire spectrum of the light flux will be absorbed, which is called the absorption maximum of this gas. At the same time, the gas concentration in the flask is higher, the greater the absorption will be observed.

Measure the concentration of a gas in the gas mixture by measuring the absorption of the appropriate wavelength, the fact that different absorption maxima correspond to different gases. Thus, determine the concentration of each of the gases in the engine exhaust can be measured by a decrease in the intensity of the light flux in the part of the spectrum that corresponds to the absorption maximum of a certain gas.

The spectrometric unit of the device works as follows:

Through the measuring cuvette, which is a tube with closed optical glass ends, pump out the exhaust gases, pre-filtered and purified from soot and moisture. On one side of the tube, the emitter is installed, which is a helix heated by an electric current, the temperature of which is strictly stabilized at one mark. Such a radiator generates a stable stream of infrared radiation.

On the other hand, the measuring cuvette is installed by light filters, which, from the entire radiation stream, are isolated those wavelengths that correspond to the absorption maxima of the gases under study. The flow, after passing the light filters, falls into the IR-radiation receiver, which measures the intensity of this stream and converts it to information about the concentration of gases in the car exhaust.

Since this method is applicable only to measure the concentration of CO 2, CO and CH, in the next step, a mixture of exhaust gases from the measuring cuvette comes in series to the electrochemical type sensors for measuring oxygen O 2 and nitrogen oxides NO x. At the same time, electrochemical sensors produce an electrical signal with a voltage, proportional to the concentration of oxygen and nitrogen oxides.

Thus, measurement of the concentration of all significant gases is performed: CO, CH and CO 2 -Shrometric method, O 2 and NO X - electrochemical sensors. Treatment of signals from the spectrometric unit and electrochemical sensors in a modern gas analyzer is performed using a microprocessor electronic circuit.

After signal processing, the content information is displayed on the instrument screen: CO, CO 2 and 2 - in percent, and CH and NO X - in PPM (Parts Per Million), "parts per million". The designation in PPM is due to the fact that the concentration of such gases in the exhaust is extremely small, and therefore it is inconvenient to use interest to indicate their quantity.

The ratio between percentages and PPM can be described by the following equality:

For example, in the exhaust gases of the usual internal combustion engine of the passenger car, the CH content is about 0.001% -0.01%. The complexity of using such values \u200b\u200band predetermined the mass spread of PPM as a unit of designation concentration.

The gas analyzer is a complex device whose quality is primarily determined by the accuracy and reliability of the spectrometric unit. The spectrometric unit is the most complex and expensive part of the device, therefore, during operation, it is very important to create conditions for its safety and durability. Says, moisture and other mechanical particles, settled on the walls of the block, lead to a noticeable scattering of the indications of the spectrometric unit, and ultimately - to its breakdown. Therefore, before getting into the measuring unit, the exhaust gases must undergo special training, which is usually out of several stages:

rough purification of exhaust gases. It is performed using a filter that is installed at the input to the instrument or directly in the sample intake probe. At this stage, the exhaust gases are cleaned of soot and other large mechanical particles.

cleaning exhaust gases from moisture. It is performed using a moisture separator that can have a variety of designs. At this stage, the flow of gases is separated, and the drops of moisture are removed, which are condensed on the inner surfaces of the probe, as well as the connecting hose. Deleting condensate from the drive is made either automatically or manually operated.

thin filtering. With the help of a fine cleaning filter, the final filtering of the smallest mechanical particles is performed. Fine cleaning filters can be several, while they are installed successively by each other.

Found in the internet here is such a program. Someone tried? Well, what thoughts on this program? Description and screens below

Gas analyzer based on the enlightenment coefficient of infrared rays through the filter film. Such a primitive method for measuring the percentage of CO2 in the engine exhaust gives a greater error, but easy to manufacture. Factory gas analyzers with high accuracy determining CO2 content cost about 300 dollars, and this you can collect yourself from simple parts. After the manufacture, settings and testing of this gas analyzer of discrepancies in the measurement with the present turned about 0.5% in one direction or the other.

For simplicity of the manufacture of a gas analyzer, all the calculated part, tincture and display of the result is done by the method.

The assembly scheme and the gas analyzer connectivity to the computer.

Filter manufacturing

The most difficult in the manufacture will make a filter film that will have to pass only those infrared rays that were refracted by carbon dioxide (CO2). For the manufacture of the film you need:

1. 2nd gramman

2. Aluminum powder 0.5 grams

3. Epoxy resin (already divorced with a hardener) of a transparent color of 10 grams.

All this is mixed in the scalable package and applied to ordinary glass. The thickness of the frozen film should be 0.2 mm

Other components

Remember that the diode must be infrared, it is easy to find, distinctive features, it is white. When sunbathing he has no glow. (In everyday life, such diodes put into remote controls).

Phototransistors look different, the main thing is that it has a working range of frequencies of the received radiation was like an infrared LED. Now come to any radio store and tell me infrared optocoupler (infr. LED and phototransistor).

Since our scheme is satisfied primitive, it will be very sensitive to temperature changes and the temperature sensor has been made for greater accuracy. In this scheme, the temperature measurement sensor from the usual DT-838 Digital Multimeter tester is used (the usual cheap "Cesca" for 200 rubles). Of course, the thermistor or thermal transistor can be used as a sensor, but then large deviations can be obtained as in this scheme, testing and tuning was carried out with a temperature sensor from "Cesca".

Data processing

Next after connecting the device to a computer, run the program "FRIZO gas analyzer". Select the COM port to which everything is connected and press the start, if the sensor is successful, the program will show that the connection is installed.

Congratulations on your successful assembly, installation and setting of the gas analyzer, you can now install the sensor in the car exhaust pipe measure the percentage of CO2 in exhaust gases. Remember that the accuracy of the device + -0.5%.

The gas analyzer is an electronic optical device for measuring the volume fraction of components in the exhaust engine gases.

Gas analyzes are 1,2,3,4,5-component. Measured exhaust components: CO, CH, CO2, O2, NOX. We know that all modern gasoline cars (with the exception of cars with direct fuel injection into cylinders and layer-by-layer mixture) on the steady modes (except for the full load mode) should operate with a stoichiometric ratio of air / fuel (lambda equal to 1). Moreover, the accuracy of maintaining this ratio is sufficiently high (lambda \u003d 0.97-1.03). Lambda is an integral parameter to estimate the quality of the working mixture. And the combustion quality of the mixture can be estimated according to the composition of the exhaust gases. For diagnostic tasks, 4 and 5 component gas analyzers will be correct, and those that are capable of calculating the lambda coefficient will be used.

For autodiagnosuit, the 4-component gas analyzer is indispensable. It helps to look inside the combustion chambers of the working engine and determine how the process of burning fuel and air mixture is. This mixture should, if possible, completely burn in the engine so that the maximum possible engine power can be achieved with a minor fuel consumption and hold the harmful substances from the very beginning with such insignificant, as it is possible. Absolutely perfect combustion is impossible even with an ideal air-fuel mixture, since it is too small for this, even with the best constructive design and optimal adjustment of all components important for combustion. From the theoretical point of view, the combustion would be perfect with the ratio of the weight of fuel and air 1: 14.7 or, representing in the volume, 1 liter of fuel mixed with 10,000 liters. This ratio denote Lambda.

The analyzed gas enters the analyzed cuvette where the components defined, interacting with radiation, cause its absorption in the corresponding spectral ranges. The radiation streams of the characteristic areas of the spectrum is released by interference filters and is converted to electrical signals proportional to the concentrations of the analyzed components. The electrochemical sensor when reacting with oxygen issues a signal proportional to oxygen concentration. The value of L is calculated by the gas analyzer automatically according to the measured CO, CH, CO2 and O2.

Modern high-class gas analyzers, except reliability and convenience in work, have many additional features. They can measure the rotational speed of the engine, the oil temperature, as well as to memorize the intermediate measurement protocols and transmit results to a personal computer or print them on the built-in printer.

Very important from the point of view of the performance of the gas analyzer is its reliability. Since, in its device, a gas analyzer is a complex electronic device to repair it on its own, as a rule, it is impossible and have to contact the company service center, which is extremely inconvenient, so when choosing a gas analyzer model, you should pay attention to its protectedness from external influences and pre-training block gases.

Hello everyone! In this article, I will tell you how to make a simple gas leakage sensor with your own hands from available details.
Probably, now even any schoolboy knows that such a dangerous gas as methane has no smell, and detect it in the air without special devices is simply not possible. Methane is the main component of natural gas. Methane, the same gas that flows through the pipes and at your home, for the low change that smelling additives specially add to it so that it can be found to be detected by the sense of smell.

But if you can teach it, then why do you ask the sensor you? The fact is that a person can teach the already dangerous concentration of gas. The sensor has the same sensitivity. And if there is a small leakage of gas in the room for several hours - this concentration may not be smell, but there will be 100% danger of an explosion. To avoid this to avoid and descending the novice gas concentrations in the air and use gas availability sensors.
This, of course, most likely a test project that shows the basic principle of working with a gas sensor, but no one will prevent you from improving and make a serious project from it.
I will give a list of parts and materials that are necessary for the construction of our sensor. (Link to the store)
1. .
2. Battery 9V and connector.
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4. .
5. .
6. (Any structure N-P-N is suitable).
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11. Other materials such as soldering iron, solder, flux and wires.

From the article you will learn how the lambda probe is made with your own hands and whether it is worth installing it on your car. From how qualitatively combines the fuel-air mixture in the engine, its efficiency depends. It is very important to choose the optimal proportion of the content of gasoline and air depending on the load on the engine.

If in the old cars, all the quality settings and quantity of fuel depended on the adjustments of the carburetor, then in modern things are somewhat different. Everything is given in the reliable hands of microprocessor equipment and a huge number of sensors.

How the injection injection system works

You can select the several most important nodes that are in the injection system:

1. Fuel tank.
2. Fuel in one case with pump and filter.
3. Fuel ramp (installed in the engine compartment on the intake manifold).
4. Nozzles providing gasoline mixture in combustion chambers.
5. Control block. As a rule, it is mounted in the car's cabin, allows you to control the supply of the fuel and air mixture.
6. The exhaust gas production system, which ensures the complete destruction of harmful substances.

It is in the latter that the lambda-probe is deceived. With your own hands ("Lancer 9" or "Lada" you have, it does not matter) to make it can be quite simple. But it is necessary to realize all the consequences of the installation of the "plug". Lambda-probe freezing with their own hands on the "prior" can be made and simple design, in any case it will have a significant impact on the engine work.

How many sensors in the car

Mounted in a system of exhaust gases of modern cars with an injection fuel injection system. The system can be both one and two oxygen sensors. If one is installed, it is located after a catalytic neutralizer. If two, then before and after.

Moreover, one measures the percentage of oxygen immediately at the output from the cylinders and sends its signal to the electronic control unit. The second, which is mounted after the catalyst, is required to adjust the readings of the first.

The principle of functioning of the lambda probe

All automotive electronics, which is responsible for the correct formation of the mixture, is involved in the distribution of fuel in the nozzles. Using the oxygen sensor, the required amount of air is determined to formed a high-quality mixture. Due to the thin settings of the lambda probe, it is possible to achieve a high degree of environmental friendliness and efficiency.

Fuel combines completely, on the outlet of the pipe almost clean air is plus ecology. The exact dosage of air and gasoline is a win in fuel economy. Of course, there is a stable engine operation with oxygen sensors. But due to the fact that it is manufactured from precious metals, its cost is extremely high. And when it fails, the replacement will turn into a penny. Therefore, the thought arises: "But there is a lambda-probe lambda, with their own hands (VAZ-2107 even needs to replace the oxygen sensor) it will not be difficult to make it."

Design features of the oxygen sensor

The appearance of this device is simple - the long electrode-housing, from which the wires are departed. On the housing, platinum spraying (it is about this precious metal and was discussed above). But the internal device is more "rich":

1. Metal contact that connects wires to connect with an active electrical sensor element.
2. Seal of dielectric to ensure safety. It has a small hole through which air enters the body.
3. The zirconium electrode of the hidden type, which is inside the ceramic tip. When current flows through this electrode, it is heated to a temperature in the range of 300 ... 1000 degrees.
4. Screen protection with hole for removal of exhaust gases.

Types of sensors

Two main types of oxygen sensors, which are currently used in automotive techniques:

1. Broadband.
2. Two-point.

Regardless of the type, they have a practically identical device internal. External similarities, as you understand, are also available. But the principle of operation is significantly different. Broadband oxygen sensor is an upgraded two-point.

It has a pumping component, which, due to voltage fluctuations, gives a signal to the electronic control unit. On this element, current flow can either amplify or become weaker. At the same time, a small amount of air enters the gap and analyzed. It is at this stage that the concentration of CO in the spent gas occurs. But sometimes it is made and the lambda-probe lambda-probe is installed. "Chevrolet Lanos", for example, works with it stably and does not produce errors after filling with poor gasoline.

Sensor definition of oxygen sensor

Of course, this element is not eternal, despite its high cost and platinum in the composition. Of course, the lambda probe is no exception and one great moment can order for a long time. And some symptoms will be manifested:

1. Radically increases in the exhaust gases, the level of content of CO. If an oxygen sensor is installed on the car, and the level with extremely high, this suggests that the control device has failed. It is possible to determine the content of harmful substances only with gas analyzers. But for personal purposes it is unprofitable.
2. Sharply pay attention to the on-board computer. See what the current consumption of gasoline. This is the easiest way. You can also judge the frequency of refueling.
3. And the last feature is a lamp-littered lamp on the dashboard, signing about the presence of malfunctions in the engine.

If there is no ability to analyze exhaust gas using a special device, you can make it visually. Light smoke is a sign that in the fuel mixture too much air. Black speaks about a large number of gasoline. Consequently, one can judge the wrong operation of the system. But the picture is different if there is a lambda probe cheating. With your own hands ("Volkswagen", VAZ, "Toyota" - for any car) This device is made quite simple.

Causes of breakdowns

It is worth paying attention to the fact that the oxygen sensor is in the epicenter of fuel burning. Consequently, the composition of gasoline has a significant impact on the lambda probe. If gasoline contains many impurities, does not correspond to GOST, low quality, then the oxygen sensor will give an error or incorrect signal to the electronic control unit. In the worst case, the device fails. And it happens because of the high lead content, which is deposited on the sensor and breaks its functioning. But there may be other causes of breakdowns:

1. Mechanical impact - Vibrations, too active operation of the car, lead to damage or enroll the case. Implement repair or recovery is not possible, rational output is the purchase of new and installation.
2. Incorrect operation of the fuel feed system. If the fuel-air mixture does not completely burn, the soot begins to settle on the lambda probe body, and also gets inside through the air intake holes. Of course, the first time helps cleaning the device. But if it needs this procedure more and more often, you will have to install a new device.

Try time from time to time to diagnose your car. In this case, for you there will be no unexpected failure of any element.

Diagnostics of faults

Of course, the most accurate response about breakdowns will give only diagnostics on specialized equipment. But it is possible to identify the sensor breakage yourself and it is enough to read carefully about the characteristics of the sensor and its characteristics. But the lambda probe is extremely rarely established. With your own hands (VAZ-2114 or any other car, if you have), you can make a shower cap from the remedies literally. The troubleshooting algorithm is:

1. Open the hood and find the exhaust manifold. It is necessary to carry out work on the cooled engine, as you can get serious injuries. Find on the catalytic neutralizer lambda probe.
2. Spend an external inspection. Pollution, soot, light raid - signs of incorrect operation of the fuel system. Moreover, the last sign suggests that too much lead in the gases.
3. Conduct the replacement of the oxygen sensor and diagnose the entire fuel system again. If contaminants are not observed, you need to continue troubleshooting.
4. Disconnect the sensor plug and attach a voltmeter to it with a scale of up to 2 volts. Run the engine and increase the revolutions up to 2500 per minute, then reduce up to the idle value. The change in voltage should be insignificant - in the range of 0.8..0.9 volts. If there is no change, or the voltage is zero, you can talk about the sensor breakage.

You can also judge breakdown by other characteristics. In a vacuum tube, create artificially vacuum. In this case, the voltage must be very low - less than 0.2 volts.

Oxygen sensor resource

To ensure uninterrupted and stable car work, you need to regularly conduct a technical inspection. For example, lambda probe needs inspection every 30,000 mileage kilometers. Moreover, he has no more than one hundred thousand resource - it is not necessary to operate a car with an old sensor - it will only lead to the fact that the engine will have to repair much earlier. And the question arises - will the lambda probe be suitable for your car? You can make such a device in a few minutes with your own hands on Kalina.

But there is one nuance. The motorist cannot guarantee the fact that the fuel that he fills the car, high-quality. Of course, everyone got used to pour that gasoline, which is sold at his favorite refueling. But who knows what kind of composition from gasoline, which spill there? Therefore, try to trust the "brand" refueling, which will be delivered by your name. But if there is no good refueling, then you will have to be content with what is available. And the burning Lamp of the DVS error is a frequent phenomenon, to get rid of which will help the installation of a deception.

Homemade

It all depends on what means you have. It is worth noting that the lambda-probe freeze can be on the VAZ itself can be the most democratic, it still works reliability. The cheapest option is homemade. Bronze housing is manufactured. This metal is better to choose, as it has a very large resistance to heating. Moreover, the size of this discharge should be exactly the same as the sensor itself, the exhaust pairs did not sucplerse. In fact, it is a simple hole with a small hole - no more than three mm. This space bucket is screwed into the sensor. And the lambda probe itself is installed in the spacer.

Between the sensor and the hole in the disc is a layer of ceramic crumb, on which the catalyst layer is applied. Due to this passes through a thin hole and oxidized by the crumb. The result is a significant reduction in the level of CO. Therefore, a standard oxygen sensor is deceived. But such devices can be installed on budget cars. More expensive cars should not be subjected to alterations.

Electronic destruction

But if there are skills in the installation of electrical circuits, you can make a self-made device. You will need only one of these two elements - a resistor or condenser. But this is not suitable for all lambda probe. With your own hands (Subaru Forester or VAZ, it does not matter) It is possible to make it one of the proposed options. But be careful, because the misunderstanding of the work of the face will affect the functioning of the entire control unit. And if not sure, it is better to purchase ready-made on the microcontroller. It is good because it can independently carry out the following actions:

1. Estimate gas concentration on the first sensor.
2. Next occurs the formation of a pulse that corresponds to the signal that was obtained earlier.
3. Displays averaged readings for the electronic control unit, which allow the engine to work normally.

Electronic Control Block Firmware

The most effective way is to completely change the program in the control unit. The essence of the whole procedure is to get rid of completely or partly from any reaction to the change in the readings coming from the oxygen sensor. But pay attention to the fact that the warranty disappears on the car. Therefore, for new cars, this method, as, however, is not suitable for any other.

Conclusion

And most importantly - think whether it is worth the heater? Do I need to do such a detail at all as a lambda probe cheating, do it yourself? "Lancer 9", say, the car is not a budget, but a high class, so whether there is a meaning of violating his design with various homemakes? Is it reasonable? If there is money on an expensive car, then there must be tools and to maintain it in working condition. If not so, then why did you get such a car?