The amount of emissions of harmful substances into the atmosphere is regulated by strict environmental standards in most countries of the world, including the Russian Federation. To reduce the level of harmful fumes, catalytic converters (or as they are also called catalysts) were created. These devices reduce the amount of harmful substances that enter the air along with the exhaust gases generated during the operation of the internal combustion engine.

Undoubtedly, catalysts are essential components of a car, but their efficiency is due to certain conditions. During the operation of the neutralizer, it is necessary to control the composition of the fuel-air mixture, otherwise the useful element will cease to perform its functions. To keep the device working as long as possible, special oxygen sensors are used, also known as oxygen sensors, O 2 concentration sensors or lambda probes (LZ).

What is a lambda probe

If we talk about what the lambda probe is responsible for, then the easiest way is to describe it as a device that determines the level of oxygen that is contained in the exhaust gases.

The fact is, insufficient air volume in fuel system (λ\u003e 1 - lean mixture) usually results in hydrocarbons and the resulting carbon monoxide not being completely oxidized. If there is oxygen, on the contrary, there is too much in this mixture (λ< 1 - rich mixture), then nitrogen oxides will not decompose into oxygen and nitrogen. Therefore, the presence of LZ in any system is simply necessary.

If we consider what a lambda probe is in a car, based on its design, then the oxygen sensor consists of the following elements:

• Ceramic tip (usually made of zirconia) equipped with protective screens and sampling holes exhaust gases and atmospheric air. These screens are the working elements of the LZ.
• Thermally conductive heating elements that are located inside the ceramic tips.
• Electrical signal current collectors located in the middle of the oxygen sensors.

All these components (except for the sensitive parts of the tips) are closed by a metal body with a thread, thanks to which the part is fixed to the body of the receiving pipe.

The principle of operation of lambda probes

Oxygen sensors are wired with one end connected to the onboard system car, which allows you to "request" data from the LZ about the state fuel mixture once every 2 seconds. As the revs increase, the refresh rate increases.

In fact, the LZ also functions as a galvanic cell. Once installed in the exhaust manifold, the sensor heats up to 400 degrees under the influence of the exhaust gas flows from the engine. In this state, the zirconium tip “activates” and begins to “breathe” with one side of the outside air, and the other with exhaust gases. As soon as one of the electrodes detects a change in the amount of oxygen, a corresponding signal is transmitted to the control system of the machine.

The obtained information on the amount of oxygen in the mixture is analyzed by the control system, which allows maintaining the optimal (stoichiometric) ratio of air and fuel in the combustion chambers of the vehicle.

Helpful! The stoichiometric ratio of oxygen to fuel should be in the order of 14.7: 1.

To provide a more accurate data control, a second sensor is used, which is located behind the catalyst. However, the number of lambda probes can be higher.

How to determine how many oxygen sensors are installed in a car

To find out how many lambda probes are in your car, you can contact a car service, where you will be given a printout with data on LH diagnostics (usually this is a snapshot of the bottom of the car with highlighted sensors). However, you can save money and find them yourself.

First of all, you need to find out in what year the car was manufactured. If you are the owner of a PBX manufactured before 2000, then, most likely, only 1 LP is installed in it. In more modern cars produced after "zero" there are usually 2 or 4 sensors.

To determine their number even more accurately, it is necessary to clarify the engine size. If it is:

• less than 2 liters, then in the car you will find 2 LZ (one will be located in the engine compartment, where you can easily notice it, and the second - under the bottom of the car);
• more than 2 liters, then the car will have 4 sensors (2 upper ones located in the engine compartment and 2 lower ones - under the bottom of the car).

Finding the upper sensors is quite simple (they are most often changed), for this:

• Open the hood of the car.
• Center engine compartment under the plastic cover with the name of the car brand, you will find the car engine.
• Look around the engine and look for massive pipes (exhaust manifold) that adjoin the engine on one side and extend inward on the other.
• Find a small cylindrical part on the exhaust manifold, the length of which will be about 5-7 centimeters. This will be the lambda probe (or several, in this case one sensor will be located on the right and the other on the left).

It is worth noting that information about what the lambda probe is needed for and where it is located is of interest to car owners far from idle interest. The point is that according to service books different cars these elements need to be changed after a certain run. Typically, LZs that have operated more than 80 thousand kilometers are subject to replacement, however, based on practice, the sensors are able to withstand loads twice as much if you adhere to several recommendations.

How to extend the life of lambda probes and when to change it

Knowing what the lambda probe affects, it is quite easy to determine the malfunction of this element. For example, if you notice that:

• on idle or at low gas the engine runs unstably or completely stalls;
• fuel consumption has increased significantly;
• the dynamic characteristics of the car have deteriorated sharply;
• after the engine was turned off, a kind of crackling appeared in the catalyst area, accompanied by an unpleasant smell of hydrogen sulfide (or, as the common people say, "rotten eggs");

then, most likely, the time has come to change the LZ and this element will not be able to extend the "life". However, if all systems are working properly, then the service life of the sensor can be increased if:

• Use only high quality gasolinerecommended for your vehicle.
• Choose tested fluids with additives, accompanied by certificates of conformity.
• Never use sealants to fix the sensors (especially silicone compounds).
• Do not start the engine several times in a short period of time.
• When checking the functionality of the cylinders, do not disconnect the spark plugs.
• Do not overheat exhaust system machines (oxygen sensors can only withstand up to 950 degrees).
• Do not use chemically active compounds for processing probe tips.
• Make sure that the connection between the sensor and the pipe remains tight.

By adhering to these tips, you will be able to operate the LZ on your car longer.

In custody

One should not neglect such a seemingly simple element from the point of view of design as a lambda probe, since it plays an important role in the functioning of the main systems of the machine. The cost of a new LZ is about 1,500 - 2,000 rubles, so you can save on its replacement if you operate the car, taking into account the recommendations of specialists and make timely diagnostics.

Unfortunately, not all car owners know what a lambda probe is and what it is needed for. A lambda probe is an oxygen sensor that allows electronic system control and balance the correct ratio of air and gasoline in the combustion chambers. It is able to timely correct the structure of the fuel mixture and prevent destabilization of the engine's working process.

This rather fragile device is located in a very aggressive environment, therefore its operation must be constantly monitored, since if it breaks down, further use of the car is impossible. Periodic check of the lambda probe will guarantee the stable operation of the car vehicle.

The principle of operation of the lambda probe

The main task of the lambda probe is to determine the chemical composition of exhaust gases and the level of oxygen molecules in them. This figure should range from 0.1 to 0.3 percent. Uncontrolled exceeding of this standard value can lead to unpleasant consequences.

With the standard assembly of the car, the lambda probe is mounted in the exhaust manifold in the area of \u200b\u200bthe connection of the pipes, however, sometimes there are other variations of its installation. In principle, a different arrangement does not affect the performance of this instrument.

Today, you can find several variations of the lambda probe: with a two-channel arrangement and a broadband type. The first type is most often found on old cars produced in the 80s, as well as on new economy class models. The wideband type sensor is inherent in modern cars of the middle and upper class. Such a sensor is able not only to accurately determine the deviation from the norm of a certain element, but also to timely balance the correct ratio.

Thanks to the diligent work of such sensors, the working life of the car is significantly increased, fuel consumption is reduced and the stability of the retention of speed increases idle move.

From the electrotechnical point of view, it is worth noting that the oxygen sensor is not able to create a homogeneous signal, since this is prevented by its location in the collector zone, because in the process of reaching the exhaust gases of the device a certain number of operating cycles can pass. Thus, we can say that the lambda probe rather reacts to the destabilization of the engine, which it actually subsequently notifies the central unit and takes appropriate measures.

The main symptoms of a lambda probe malfunction

The main symptom of a malfunction of the lambda probe is a change in engine operation, since after its breakdown, the quality of the supplied fuel mixture into the combustion chamber deteriorates significantly. The fuel mixture, in fact, remains uncontrolled, which is unacceptable.

The reason for the exit from the operating state of the lambda probe may be the following:

• depressurization of the case;
• penetration of outside air and exhaust gases;
• overheating of the sensor due to poor-quality painting of the engine or improper operation of the ignition system;
• obsolescence;
• incorrect or intermittent power supply that leads to the main control unit;
• mechanical damage due to improper operation of the car.

In all of the above cases, except for the last, failure occurs gradually. Therefore, those car owners who do not know how to check the lambda probe and where it is generally located, most likely, will not immediately notice the malfunction. However, for experienced drivers determining the reason for the change in engine operation is not difficult.

The gradual failure of the lambda probe can be divided into several stages. At the initial stage, the sensor ceases to function normally, that is, at certain operating moments of the motor, the device stops generating a signal, after which the idle speed is destabilized.

In other words, they begin to fluctuate in a rather wider range, which ultimately leads to a loss in the quality of the fuel mixture. At the same time, the car begins to twitch for no reason, you can also hear uncharacteristic claps of the engine, and the warning light on the instrument panel must light up. All these anomalous phenomena signal the car owner about wrong work lambda probe.

At the second stage, the sensor stops working at all on an unheated engine, while the car will signal the driver about the problem in all possible ways. In particular, there will be a noticeable drop in power, slower response when the accelerator pedal is pressed and all the same pops from under the hood, as well as unjustified jerking of the car. However, the most significant and extremely dangerous signal of a lambda probe breakdown is engine overheating.

If all the previous signals are completely ignored, indicating a deterioration in the state of the lambda probe, its breakdown is inevitable, which will cause a large number of problems. First of all, the possibility of natural movement will suffer, fuel consumption will also significantly increase and an unpleasant pungent odor with a pronounced shade of toxicity will appear from exhaust pipe... In modern automated vehicles in case of breakdown oxygen sensor the emergency blocking can simply be activated, as a result of which the subsequent movement of the car becomes impossible. In such cases, only an emergency call for a tow truck can help.

However, the worst case scenario is depressurization of the sensor, since in this case the car's movement becomes impossible due to the high probability of engine breakdown and subsequent expensive repairs. During depressurization, the exhaust gases, instead of exiting through the exhaust pipe, enter the intake channel of the atmospheric reference air. During engine braking, the lambda probe begins to record an excess of oxygen molecules and urgently supplies a large number of negative signals, which completely disables the injection control system.

The main sign of sensor depressurization is loss of power, this is especially felt during high-speed movement, the characteristic tapping from under the hood while driving, which is accompanied by unpleasant jerks and an unpleasant smell that is emitted from the exhaust. Also, the depressurization is evidenced by the visible sediment of soot formations on the body. exhaust valves and in the area of \u200b\u200bcandles.

How to determine a malfunction of a lambda probe is described in the video:

Electronic check of a lambda probe

You can find out about the state of the lambda probe by checking it on professional equipment. For this, an electronic oscilloscope is used. Some experts determine the performance of the oxygen sensor using a multimeter, however, it can only state or deny the fact of its breakdown.

The device is checked during the full operation of the engine, since at rest the sensor will not be able to fully convey the picture of its performance. In case of even a slight deviation from the norm, it is recommended to replace the lambda probe.

Replacing the lambda probe

In most cases, a part such as a lambda probe cannot be repaired, as evidenced by statements about the impossibility of repairing from many car manufacturers... However, the overestimated cost of such a node is official dealers discourages any desire to acquire it. The optimal way out of this situation can be a universal sensor, which is much cheaper than its native analog and is suitable for almost everyone car brands... Also, as an alternative, you can purchase a sensor that was in use, but with the duration of the warranty period, or a completely exhaust manifold with a lambda probe installed in it.

However, there are cases when the lambda probe functions with a certain error due to severe pollution as a result of the settling of combustion products on it. In order to make sure that this is indeed the case, the sensor must be checked by specialists. After the lambda probe has been checked and the fact of its full operability has been confirmed, it must be removed, cleaned and installed back.

In order to dismantle the oxygen level sensor, it is necessary to warm up its surface to 50 degrees. After removal, the protective cap is removed from it and only after that you can start cleaning. Phosphoric acid is recommended as a highly effective cleaning agent, which easily removes even the most stubborn combustible deposits. At the end of the soaking procedure, the lambda probe is rinsed in clean water, thoroughly dried and installed in place. In this case, do not forget about lubricating the threads with a special sealant, which ensures complete tightness.

It is very difficult, so it needs constant support of its efficiency and timely preventive maintenance. Therefore, in case of suspicion of a malfunction of the lambda probe, it is necessary to immediately diagnose its operability and, if the fact of failure is confirmed, replace the lambda probe. Thus, all the most important functions of the vehicle will be maintained at the same level, which will guarantee the absence of further problems with the engine and other important elements car.

The readings of the lambda probe are used to adjust the quality and quantity of the fuel mixture in injection systems... Carburetor ones are not equipped with such devices, since they lack electronic control - fuel enters the combustion chambers under the influence of vacuum. In fairness, it should be noted that the exhaust sensor is not installed on some modifications of injection engines. But these are very old cars that do not meet Euro standards.

Features of control systems

Injection motors are considered to be the most economical and efficient today. But this is when compared with carburetor engines... Achieving high performance is obtained due to the fact that there is complete control over how fuel and air is supplied to the combustion chambers. For this, several sensors are installed on the engine and intake system. With their help, all work parameters are checked. power unit... Then the data goes to electronic unit control with a microcontroller. It allows you to analyze all the data in order to correct the operation of the system.

And it should be noted that sensors are installed not only in the intake tract, but also in the exhaust. True, there is only one device - a sensor that measures the oxygen content in the exhaust gases. How much air will be supplied to the cylinders depends on its work. Consequently, the composition of the fuel-air mixture will change.

Sensor design

Now let's take a closer look at the lambda probe, what it is and what is its composition. The device design consists of the following components:

1. The body is made of metal, has a thread and a hexagon (for unscrewing with a wrench).
2. O-ring for sealing.
3. Current collector - for signal measurement.
4. Ceramic insulator.
5. Connecting wires.
6. Sealing sleeve for wires.
7. Contact for supplying power supply to the heating element.
8. External protection screen. It also has a small opening for air intake from the atmosphere.
9. Sensitive part of the sensor.
10. Ceramic tip.
11. Screen for protection. It has a hole in which the exhaust gas enters.

From what purpose the device has, you can understand where the lambda probe is located in the car. Some systems have two sensors - they are installed before and after the collector. Some are equipped with just one device.

What is the device for?

The task of the device is to estimate the amount of oxygen that is not burned out during engine operation. But not everything is as simple as it seems at first glance. In fact, there is no device that can measure the amount of oxygen. And the readings of the lambda probe indicate not how much oxygen is in the exhaust tract, but what the difference is between the voltage on the "reference" part and the active one (located in the exhaust tract).

Most efficiently, the air-fuel mixture will burn only if the ratio of the two main components (air and gasoline) is always the same. The combustion of one liter of gasoline will require an air volume of 14.7 liters. The mixture is called lean if the amount of air is more than necessary and the amount of gasoline is less. And the mixture is considered enriched if there is more gasoline and less air. Any of these conditions affects gas mileage, vehicle throttle response, and engine power.

Engine operating modes

Since the engine does not work in one steady state, the loads are constantly changing, so the proportion is not always observed. To control the amount of air in throttle a lambda probe is installed.

The electronic microprocessor control unit evaluates the composition of the air-fuel mixture only according to the readings of the lambda probe. If the quality does not correspond to the norm, then an adjustment is made, a mixture is supplied that is more suitable for specific regime engine operation. For this, a signal is sent to the injectors to increase or decrease their opening time. In fact, the amount of fuel supplied to the combustion chambers depends entirely on how long the injector solenoid valves are open.

The main elements of the sensor

Structurally, the O2 sensor consists of the following components:

1. Platinum outer electrode that is in contact with the exhaust gases.
2. Housings.
3. An internal platinum electrode that is in contact with atmospheric air (it is taken as a standard).
4. Protective pipe.

Platinum is a fairly sensitive metal that can react to any changes in the composition of the air. By the way, it should be noted that the sensor does not directly measure the amount of oxygen in the exhaust tract. And what processes occur during work - you will find out further.

How the sensor works

If you look closely, the principle of operation of the lambda probe is not very complicated. But it is very difficult to implement the process so that data on the composition of exhaust gases appear at the output. To begin with, the sensor requires the presence of reference air - this is required to "understand" that there are some changes in the composition of the gas. It is for this reason that one sensor consists, in fact, of two - one measures the composition of the air in the atmosphere, and the other in the exhaust tract.

Thanks to such a simple system, the sensor “senses” the difference in the oxygen ratio. But in order to control the operation of the engine, it is necessary to send electrical signals to the ECU. The sensor design consists of electrodes and solid electrolytes, therefore, when exposed to them, a reaction occurs. You can even compare a lambda probe (which you already know) with a regular battery. Oxygen acts only as an active element, which is contained both in the atmospheric air and in the exhaust gases (albeit in a smaller proportion).

Chemical reactions in the sensor

If you take a closer look, the readings of the lambda probe are some tension. It changes depending on the percentage of oxygen in the exhaust system. A potential appears on two electrodes. With a decrease in the amount of oxygen, the voltage increases, with an increase, it decreases. The pulse that appears at the output of the device goes to the electronic control unit.

The microprocessor control unit has a built-in memory in which all the main parameters are registered, including the operation of the lambda probe. The controller compares the readings recorded in the memory with those received from the sensor, on the basis of which it corrects the operation of the fuel injection system.

When used, chemical reactions, which makes it possible to simplify the design of the device. At the base is a ceramic tip. Typically, it is made from zirconia or titanium dioxide. The tip is covered with a layer of platinum (that's why the cost of sensors is high). The tip and the spray are two elements that react, they are the electrodes.

Sensor heating: why is it needed?

There are two types of sensors in fuel injection systems - heated and non-heated. Devices without additional heating are divided into two types:

1. With one black wire - a signal is transmitted through it.
2. With two wires: black - signal, gray - ground (minus power supply).

If there is a heating element, then the sensors have the following outputs:

1. Three wires: black - signal, white (2 pcs.) - heating element.
2. Four wires: black - signal, gray - ground, white - heating element power supply.

Why do I need to warm up the sensor? The problem is that it is possible to effectively measure the oxygen content only if the temperature is more than 300 degrees (sometimes it is necessary to warm up more). Only at this temperature can the tip obtain the required conductivity.

How does the sensor injection system work?

In order to provide the desired operating mode, the sensor is placed as close as possible to the exhaust manifold. Thanks to this, the lambda probe is heated, the sensor goes to normal mode work. As you can see, the device does not participate in the operation of the system until the engine warms up.

Before the sensor is switched on, the electronic control unit is guided only by signals from other devices. The disadvantage of working in this mode is that it is impossible to achieve the ideal formation of the air-fuel mixture. Consequently, complete combustion of the mixture cannot be achieved - this leads to the fact that the emissions from the vehicle increase.

And since modern cars must comply with the Euro environmental standards (otherwise they will not be released either on the market or on the roads), it is necessary to complicate the injection system. By the way, this allows you to reduce fuel consumption due to the fact that with the help of a lambda probe (its price is not less than 1,500 rubles), it is possible to achieve complete combustion of the entire mixture entering the intake tract.

Heated device

There are sensor models equipped with heating elements. Thanks to such a simple device, it turns out to quickly reach the optimal temperature. The principle of operation of the lambda probe on VAZ and foreign cars is the same, the heating system allows you to enter the operating mode in a shorter time. Consequently, the amount of harmful emissions is reduced. This ensures that the vehicle meets the environmental standards adopted in Europe. The heating element is powered directly from the vehicle electrical system.

Varieties of devices

There are several types of sensors, they differ only in the type of measurement. Two-point sensors are sensors that allow measurements to be made simultaneously at two locations. Used extensively in older cars. More modern systems motor controllers are equipped with broadband devices, which are more functional and modern.

Basically, broadband probes consist of a point-to-point and terminating ceramic element. The essence of the work does not change - when the oxygen concentration increases or decreases, a corresponding signal is sent to the electronic control unit.

Two sensors in the system

Most modern cars are equipped not only with a lambda probe (price from 2000 rubles and above), but also with a catalytic converter. This is a device that can significantly reduce the amount of harmful substances entering the atmosphere. And in this case, two sensors are installed in the exhaust tract at once - at the inlet and outlet. In fact, they allow measuring the oxygen and CO content before and after the neutralizer. Therefore, the efficiency of the entire exhaust system is thus assessed.

Features of the system

In fuel injection systems, two lambdas can also be used. These sensors measure the oxygen content and make it clear to the electronic control unit in which direction it is necessary to adjust the ignition or the composition of the fuel mixture so that the amount of harmful substances in the exhaust is minimal.

Dual sensor systems ensure that the exhaust is extremely low in pollutants. But the complication of the design leads to the fact that its reliability deteriorates. A couple of times they refueled the car with low-quality fuel - they spoiled the catalyst. And then - incorrect readings of the sensors, malfunction of the injection system.

And even if you follow all the requirements, the catalyst will break down sooner or later, since its resource is not very large. And the cost of this element, even on the most budget cars, is transcendental. Therefore, many motorists, in order to save money, cut out the catalyst and replace it with a flame arrester. In fact, this is a regular piece of pipe of suitable dimensions. And so that the second lambda probe does not give an error, they put a snag. This is a spacer that is mounted on the sensor.

With the help of a trick, it turns out to distance the gas flow from the sensor tip. This affects the readings of the element coming to the electronic control unit. Therefore, the microcontroller senses the difference in readings and does not notice the absence of a catalyst.

Major malfunctions

There are several main signs by which one can judge about a malfunction of the lambda probe:

1. Decreased dynamics.
2. Significant increase in fuel consumption.
3. Unstable engine idling.
4. Cracking or clicking noise after stopping the engine.

The downside is that breakdowns of this device are not always recognized by the self-diagnosis system. And check with simple measuring instruments in garage conditions the sensor is simply unrealistic, an oscilloscope is required. Repair cannot be done either. Only a broken wire can be repaired.

Lambda probe is a special oxygen sensor or lambda controller that allows you to monitor and measure the quantitative presence of residual oxygen in the exhaust gases of cars.

The main direction of this device is tracking and transmitting data to the electronic control system about the completeness of fuel combustion and quality, by means of fuel injection. It is through this that the optimal working conditions of the exhaust catalyst are ensured.

The prerequisites for the use of catalysts have become stringent environmental standards for automobile exhaust, since the task of these devices is to reduce carbon dioxide. In order to fully function it is necessary, uniform combustion in the cylinders burned out a strictly defined amount of air with a minimum percentage of deviation.

This precise control of the combustion fuel is ensured by a power supply system with electronically controlled injection. A lambda probe is an oxygen sensor that takes over the function of a controller in the exhaust tract.

Place of installation of a lambda probe

For the maximum efficient measurement of the indicators of the remaining air in the burnt mixture, the oxygen sensor, the lambda probe, must be mounted in the exhaust manifold, located near the catalyst.

The information will be read through the fuel system control unit, which controls the increase or decrease in the rate of fuel injection into the cylinders.

IN modern cars there is an additional lambda probe located at the outlet of the catalyst. This is necessary to increase the accuracy of the mixture preparation.

Operating principle

Oxygen sensors function according to the principle of operation:

• Based on zirconium oxide.
• Titanium oxide based. In this case, if the composition of the exhaust changes, then the electrical resistance changes
• Broadband. It is associated with a change in voltage and current polarity. Its peculiarity is the ability to respond not only to deviations in the composition of the working mixture, but also to its numerical value.

The work of the lambda probe is based on the use of a special galvanic cell, in which a pair of electrodes is located. For one of them wrap goes exhaust gases, and the other is characterized by clean atmospheric air.

The working mechanism of the lambda sensor starts after warming up to 300 or more degrees, at the moment when the zirconium electrolyte becomes a conductor, and the quantitative difference between the oxygen supplied from the exhaust pipe and the atmosphere is aimed at the appearance of voltage on the electrodes.

When the engine starts and warms up, the oxygen sensor does not affect the control of the fuel injection, and the correction is carried out by other signaling devices (sensors for the temperature of the cooling system, throttle position, speed, etc.).

In addition to heated zirconia, there are cold controllers based on titanium dioxide. They are not designed to generate electricity, but to change the air flow resistance, which serves as the main signal card for injection control systems.

The advantage of such a lambda oxygen sensor is that its operation begins immediately after starting the engine, but it has not received widespread acceptance, since it is made in a complex design and is expensive. There is a lambda probe of this type in bMW models, Nissan, and Jaguar.

Reasons for failure

The oxygen sensor can malfunction or start to malfunction for a number of reasons:

• if there is a break in the supply or control electrical circuit;
• there was a short circuit;
• if, when using fuel with additives, a blockage has occurred. Lead, silicone, sulfur become the most harmful;
• due to regular thermal overloads associated with ignition problems;
• mechanical damage occurred after off-road trips.

Each sensor has its own service life and the longer it is, the slower its response to changes in the fuel mixture becomes. The age of the sensor can be clearly seen on direct injection engines. It must be borne in mind that if the bad condition of the oil scraper rings or antifreeze has entered the cylinders, the lambda probe will not withstand the prescribed period and will have to be replaced.

Attention should be paid to the indicators of the lambda oxygen sensor. It is possible to determine that they fail by the carbon dioxide content in the exhaust, which rises sharply from 0.1-0.3% to 3%, and often 7%. If an oxygen sensor is found not to be working, it is difficult to reduce its value without repair or replacement.

Similar difficulties can arise in models with two umbrellas, if at least one of them has malfunctioned, for the working environment you will need to work on a major change in the electronics settings.

Signs of a lambda probe failure

You can determine the malfunction of the oxygen sensor by the following signs:

• a faulty sensor must be changed immediately, otherwise it is fraught with catalyst failure;
• accelerating dynamics worsened;
• intermittent idle detected;
• there are jumps in fuel consumption;
• the toxicity of the exhaust increases, the parameters of which can be determined without special equipment impossible.

So that the lambda probe does not suddenly become unjustified, it must be regularly changed, not heated sensors approximately every 50-80 thousand kilometers; heated every 100 thousand and planar every 160 thousand km. But, there is no need to rush to throw out the old lambda. To do this, you need to check the lambda probe for its real state.

It is recommended to check the lambda sensor and the system that regulates the fuel mixture every 30 thousand km. This will not protect against breakage due to mechanical damage or clogging, but will prevent breakage due to wear.

Timely replacement of the lambda probe is:

• saving up to 15% of fuel;
• reduction to a minimum of exhaust toxicity;
• the ability to extend the resources of the catalyst;
• the ability to improve the dynamic characteristics of the car.

Trouble-shooting

Officially, the technology for repairing lambda probes has not been developed. This means that in the event of a breakdown not in the overhead line, the device should be replaced immediately.

Clandestine service stations have a practice of restoring sensors that have stopped working due to carbon deposits under the protective cap, through the plaque removal technology.

This is done through flushing in phosphoric acid sensor that does not have a destructive effect on the electrodes. Such washing is not always effective, and if the sensor does not come into the working mechanism after it, it must be 100% replaced.

The amount of emissions of harmful substances into the atmosphere is regulated by strict environmental standards in most countries of the world, including the Russian Federation. To reduce the level of harmful fumes, catalytic converters (or as they are also called catalysts) were created. These devices reduce the amount of harmful substances that enter the air along with the exhaust gases generated during the operation of the internal combustion engine.

Undoubtedly, catalysts are essential components of a car, but their efficiency is due to certain conditions. During the operation of the neutralizer, it is necessary to control the composition of the fuel-air mixture, otherwise the useful element will cease to perform its functions. To keep the device working as long as possible, special oxygen sensors are used, also known as oxygen sensors, O 2 concentration sensors or lambda probes (LZ).

What is a lambda probe

If we talk about what the lambda probe is responsible for, then the easiest way is to describe it as a device that determines the level of oxygen that is contained in the exhaust gases.

The fact is that an insufficient volume of air in the fuel system (λ\u003e 1 is a lean mixture) usually leads to the fact that hydrocarbons and the resulting carbon monoxide will not be completely oxidized. If there is oxygen, on the contrary, there is too much in this mixture (λ< 1 - богатая смесь), то оксиды азота не будут разлагаться на кислород и азот. Поэтому наличие ЛЗ в любой системе просто необходимо.

If we consider what a lambda probe is in a car, based on its design, then the oxygen sensor consists of the following elements:

• Ceramic tip (usually made of zirconium dioxide) equipped with protective screens, as well as holes for the intake of exhaust gases and atmospheric air. These screens are the working elements of the LZ.
• Thermally conductive heating elements that are located inside the ceramic tips.
• Electrical signal current collectors located in the middle of the oxygen sensors.

All these components (except for the sensitive parts of the tips) are closed by a metal body with a thread, thanks to which the part is fixed to the body of the receiving pipe.

The principle of operation of lambda probes

Oxygen sensors are equipped with wiring, one end of which is connected to the vehicle's on-board system, which allows you to "request" data from the LZ about the state of the fuel mixture every 2 seconds. As the revs increase, the refresh rate increases.

In fact, the LZ also functions as a galvanic cell. Once installed in the exhaust manifold, the sensor heats up to 400 degrees under the influence of the exhaust gas flows from the engine. In this state, the zirconium tip “activates” and begins to “breathe” with one side of the outside air, and the other with exhaust gases. As soon as one of the electrodes detects a change in the amount of oxygen, a corresponding signal is transmitted to the control system of the machine.

The obtained information on the amount of oxygen in the mixture is analyzed by the control system, which allows maintaining the optimal (stoichiometric) ratio of air and fuel in the combustion chambers of the vehicle.

Helpful! The stoichiometric ratio of oxygen to fuel should be in the order of 14.7: 1.

To provide a more accurate data control, a second sensor is used, which is located behind the catalyst. However, the number of lambda probes can be higher.

How to determine how many oxygen sensors are installed in a car

To find out how many lambda probes are in your car, you can contact a car service, where you will be given a printout with data on LH diagnostics (usually this is a snapshot of the bottom of the car with highlighted sensors). However, you can save money and find them yourself.

First of all, you need to find out in what year the car was manufactured. If you are the owner of a PBX manufactured before 2000, then, most likely, only 1 LP is installed in it. In more modern cars produced after "zero" there are usually 2 or 4 sensors.

To determine their number even more accurately, it is necessary to clarify the engine size. If it is:

• less than 2 liters, then in the car you will find 2 LZ (one will be located in the engine compartment, where you can easily notice it, and the second - under the bottom of the car);
• more than 2 liters, then the car will have 4 sensors (2 upper ones located in the engine compartment and 2 lower ones - under the bottom of the car).

Finding the upper sensors is quite simple (they are most often changed), for this:

• Open the hood of the car.
• In the center of the engine compartment under a plastic cover with the name of the car brand, you will find the car engine.
• Look around the engine and look for massive pipes (exhaust manifold) that adjoin the engine on one side and extend inward on the other.
• Find a small cylindrical part on the exhaust manifold, the length of which will be about 5-7 centimeters. This will be the lambda probe (or several, in this case one sensor will be located on the right and the other on the left).

It is worth noting that information about what the lambda probe is needed for and where it is located is not of interest to car owners because of idle interest. The fact is that, according to the service books of different cars, these elements need to be changed after a certain mileage. Typically, LZs that have operated more than 80 thousand kilometers are subject to replacement, however, based on practice, the sensors are able to withstand loads twice as much if you adhere to several recommendations.

How to extend the life of lambda probes and when to change it

Knowing what the lambda probe affects, it is quite easy to determine the malfunction of this element. For example, if you notice that:

• at idle or low gas, the engine runs unstably or completely stalls;
• fuel consumption has increased significantly;
• the dynamic characteristics of the car have deteriorated sharply;
• after the engine was turned off, a kind of crackling appeared in the catalyst area, accompanied by an unpleasant smell of hydrogen sulfide (or, as the common people say, "rotten eggs");

then, most likely, the time has come to change the LZ and this element will not be able to extend the "life". However, if all systems are working properly, then the service life of the sensor can be increased if:

• Use only high quality gasoline recommended for your vehicle.
• Choose tested fluids with additives, accompanied by certificates of conformity.
• Never use sealants to fix the sensors (especially silicone compounds).
• Do not start the engine several times in a short period of time.
• When checking the functionality of the cylinders, do not disconnect the spark plugs.
• Do not overheat the exhaust system of the car (oxygen sensors can only withstand up to 950 degrees).
• Do not use chemically active compounds for processing probe tips.
• Make sure that the connection between the sensor and the pipe remains tight.

By adhering to these tips, you will be able to operate the LZ on your car longer.

In custody

One should not neglect such a seemingly simple element from the point of view of design as a lambda probe, since it plays an important role in the functioning of the main systems of the machine. The cost of a new LZ is about 1,500 - 2,000 rubles, so you can save on its replacement if you operate the car, taking into account the recommendations of specialists and make timely diagnostics.