When it was first used for general use, it was the nineties of the twentieth century. At that time, the world began to pay more attention to the environment, and thus to the quality and quantity of car exhaust. The lambda probe was supposed to be a solution to solve the problem. The innovative solution was a source of pride for producers. Especially who emphasized their pro-ecological approach by placing appropriate markings on cars, indicating the presence of a probe. For car users, all this sounded very mysterious, modern and attracted attention. What is this? What is its operation and why it fails from time to time? Damaged lambda sensor – do you know all the symptoms?
A bit of history, or how it started?
A specific solution was created in 1979. However, widespread use took place only in the nineties of the twentieth century. In the initial period, the lambda probe was used only in gasoline engines. Today it has changed. Due to extremely restrictive combustion standards, several probes are used in diesel and also diesel engines.
What lambda sensor is it and what is it for?
It is an electric sensor that is located in the exhaust system, and more specifically in the exhaust pipe in front of the catalytic converter. The task of the probe is to measure the composition of exhaust gases that come out of the engine compartment.
Internal combustion engines require a mixture of air and fuel that, in simple terms, “explodes” in the engine compartment and contributes to driving the vehicle. The purpose of the probes is also to monitor the amount of air that has not been consumed in the exhaust gases emitted from the engine. The collected information is transferred to the control computer. It on this basis selects the correct composition of the fuel-air mixture.
There should be a mixture in the engine compartment characterized by a strictly calculated ratio, which is 1 (fuel): 14.7 (air). Such a ratio ensures optimal combustion of fuel and, consequently, proper engine operation. It also reduces the amount of harmful substances that enter the atmosphere, including exhaust gases. Incorrectly selected mixture not only affects the quality of exhaust gases, but also can cause engine failure.
Why is the lambda sensor failing?
Damage to a particular device occurs under extreme conditions. Due to the fact that it is located in the middle of the exhaust system, as well as the exhaust system, it is affected by very high temperatures exceeding 300 degrees Celsius. What’s more, such elements as water, road salt, dust that escape from the outside also have an unfavourable effect. According to estimates, the probe is able to survive mostly on a mileage of about 50-100 thousand kilometres. However, the good condition of the engine and the refuelling of high quality fuel can contribute to a significant extension of the life of the device.
Symptoms of damaged lambda sensor
Among the symptoms informing about the damage of the probe, the increase of combustion, which may even exceed 50%, is mentioned first. Another symptom that can be felt by the driver is uneven engine operation. Damaged lambda sensor can be indicated by a red indicator light, which is activated on the dashboard of the car. Sometimes the failure of the device can be assessed on the basis of a coloured film appearing on the probe. The colour observed may indicate the likely cause of the abnormality. And so when we notice the colour:
red – we can suspect the presence of harmful elements in the fuel,
dark brown – then we get information about too rich air-fuel mixture,
green – we know about the leakage of refrigerant fluid,
black and greasy – we are alerted to excessive oil consumption.
Damage to the lambda probe can also be caused by irregularities in mechanical failure of its structure. For example, fusion of cables, bending, corrosion of styles or loosening of gaskets.
Repair of damaged lambda sensor
The repair should be carried out by a mechanic. In modern cars, access to the lambda probe may not be easy. In order to disassemble and replace a damaged device, many elements must be used. An important issue is also the removal of control computer errors. This can not be done without a specialized device.
A malfunctioning probe can not be ignored. Failure to take corrective action may involve high costs. It contributes to greater combustion, which is particularly severe when moving around the city. Failure to repair can also damage the particle filter. That is why it is so important not to ignore any symptoms that indicate a lambda probe failure.
One of the elements of the exhaust system is the silencer. It plays a very important role in the entire exhaust gas extraction process. Engine exhaust systems would not function well without this element. Therefore, to choose the appropriate silencer, which will meet all the standards in the form of appropriate sound intensity or engine performance parameters, please familiarize yourself with its specification. This knowledge will not only be useful for car repair shops that will be able to choose the right silencers.
Engine exhaust systems – construction types of silencers
Two types of muffler designs can be distinguished: the first one is the silencer roll construction. The housing has a round or oval cross-section. A silencer is rolled up and then joined along by rolling the formed overlap. The previously prepared elements are placed inside the silencer and the covers closing the ends of the casing are connected. Pipes are inserted through covers that are part of the silencer centre. They are welded to the housing covers.
The second one is a type of two-bay structure, which is more modern technology. It allows a better fitting of the muffler housing to the car floor plate, thanks to which the air flow resistance is lower. Two-bay dampers consist of two parts of the casing, made by stamping from a cut sheet or a steel strip. In the middle of one of them, baffles and perforated ducts are installed, which lead the exhaust gases. Due to the multi-stage process of creating this type of silencers, it is necessary to use many tools.
Silencers available on the domestic market should meet certain standards: UNECE 59 and local regulations.
Types of exhaust silencers that have the function of reducing noise
In absorption silencer the exhaust flows only through the perforated pipe and through the special openings have contact with the space. Filling with special damping wadding, which is made of steel wool or mineral glass wool. It impedes sudden increases and decreases in pressure due to its surface and inelasticity, which in turn suppresses the movement of particles and contributes to the release of heat. The absorption silencer suppresses sounds above 500 Hz. Its damping capabilities increase until the sounds reach frequencies above the value of 2500 Hz.
The silencer works on the principle of multiple reflections of the sound wave that moves with the exhaust. Losing some of the energy during rebound causes the wave attenuation. It is necessary to set several cross-sectional changes in order to make the effect optimal. This setting will cause a resonance phenomenon, i.e. the frequency of vibrations will coincide with the frequency of natural vibrations in the chamber, where the waves move. There are two types of reflective silencers:
- series resonator – resonant phenomena occur in the main exhaust line,
- bypass resonator – the phenomena occur in the branch pipe from the main duct, which leads the fumes.
During a meeting of two or more vibrations, they overlap, which can be strengthened or extinguished. The vibrating stream of exhaust gases is divided into two streams. One moves with a shorter channel, the other one with a longer one. When the two streams meet, there is interference in the form of blanking.
None of the previously mentioned silencers, suppresses sounds on all frequencies. That is why the created silencers have several methods of damping vibrations.
Engine exhaust systems – silencer damages
The silencer is not immortal or indestructible. Both inside and outside can be damaged by corrosion. Corrosion from the inside is caused by chemical condensate, which is acidic, mainly consisting of solutions of sulfuric acids, nitrous hydrochloric acid and their salts. In absorption silencers, the absorption mat absorbs condensate. In reflective and combined silencers, the condensate drops on the internal ducts of the silencer. Moving the car over unevenness, also affects the load of the muffler. Therefore, the type of steel that directly comes into contact with the condensate determines the lifetime of the silencer. The best choice will be stainless steel sheet or sheet coated with aluminium.
Remarks – assembly of the outlet system
- Even the smallest leak in the exhaust system affects the engine’s operation. All the more when it is near the engine. In case the car is equipped with a catalytic converter and oxygen sensor, leakage contributes to serious consequences, including: the catalyst is unable to remove toxic nitrogen oxides.
- The ingress of air prevents proper exhaust gas analysis.
- We treat sealing pastes as temporary repair of leakage.
- Before painting the outlet systems, the surface should be cleaned and degreased. Use only heat-resisting paints that can withstand temperatures of 800 degrees Celsius and more.
- Spare parts should be mounted using hose clamps. They should be properly mounted and selected.
- For better tightness of pipe connections, it is recommended to use a sealing paste.
- The system heats up during operation due to high temperature and can be extended up to 20 mm. When mounting and suspending the exhaust system, the rear muffler must be moved by this amount so that the pipe end does not hit the vehicle body.
The exhaust system is a very important element that plays an important role in motor vehicles. Therefore, the engine exhaust systems must be properly adjusted so that the car or other vehicle does not get prematurely broken. It is worth getting acquainted with the basic information on this topic. This will facilitate understanding, and can even help in the event of irregularities associated with the exhaust system.
Engine exhaust systems – exhaust gases
The exhaust gas is a mixture of gases and solid particles. Solids include those that are not in gas form. Water is also part of the exhaust, because it is its product and most often occurs in the form of steam. Exhaust gases get out of the exhaust systems, which are converted into energy in the process of air-fuel combustion of the resident.
Energies can be divided into three parts. The first one is in the form of vehicle propulsion. The second one is used in the cooling system and the third one escapes with the exhaust gases. In the last two cases, it is mostly lost.
Therefore, energy is noticeable under several forms:
• exhaust temperature;
• hypertension, which is a measure of potential energy;
• the speed of the tide, which in turn is associated with kinetic energy
• vibrations of the exhaust column.
Engine exhaust systems – tasks and features
The main task of the exhaust system is to discharge exhaust gases from the vehicle into the atmosphere. Second task is reduce the noise that occurs during this process. In addition, it should purify the exhaust to such an extent that the harmful components do not exceed the permissible standard specified in the regulations.
In terms of features, the outlet system should be characterized by:
• the most efficient engine operation, which is read in the full range of loads,
• flow resistance should be minimal, so that the maximum engine power will not be a problem,
• minimal heat radiation affecting the correct exhaust temperature,
• lifetime in accordance with its guidelines,
• materials that are used for production can be re-processed without any problems
• low costs.
When the exhaust system is optimally operated, you can increase the engine power and even reduce fuel consumption. The quality of the outlet system is evidenced by a slightly larger residual amount of exhaust gas in the combustion chambers. It is produced during small and medium engine loads (internal recirculation). In the case of heavy engine loads, as much as possible exhaust gases should be removed. Then you can enter the largest amount of mixture into them. That is why regular check on exhaust parts is so important.
The catalytic converter’s task
The catalytic converter is designed to reduce the amount of harmful substances contained in the exhaust. In addition, it suppresses the vibrations of the exhaust, which affects the lower volume of the engine. To ensure sealed connections of the exhaust elements, appropriate exhaust gaskets, exhaust rings, sealing cement paste for the elements of the exhaust system are used.
Water is also one of the exhaust components. Water vapour arises when the flue gas has a high temperature. Unfortunately, the farther away from the engine the temperature is lower, which can cause water to condense. It occurs when the temperature of the outlet element is lower or the same as the temperature that causes the steam to condense. In the exhaust it is 50 degrees Celsius. This can occur in all components that are cooler and the final silencers are most susceptible. The condensed liquid is not water because it contains other substances – it is called condensate. Most of it is produced during urban rides on small sections. The exhaust gases are unable to heat up the exhaust system properly.
Counteracting in the formation of condensate and exhaust back pressure
The basic action is to ensure uniform heating of all elements of the exhaust system. Unfortunately, while the engine is cold, the exhaust temperature is too low to prevent condensation.
It will be helpful to use a special construction of the silencer. It will suck up the condensate from its interior. Helpful means are also those that will limit heat emissions from the exhaust system to the outside. The reduction of thermal energy losses is also possible using properly welded elements.
Differential pressures cause the exhaust to flow because the pressure in the combustion chamber is different from atmospheric pressure. It is necessary to obtain an identical flue gas flow rate and to overcome the flow resistance that occurs during combustion. The differential pressure measured between the inlet and outlet of the silencer or the entire exhaust system for the engine operating at full speed is the resistance of the exhaust flow and is called as back pressure. The exhaust back pressure for a typical exhaust system with a catalytic converter. It should be 30 to 40 kPa, and a typical silencer has a back pressure of 10 kPa.
In recent years, much is said about air pollution, and the fight with them is at its best. The European Union has set itself the aim of improving the state of the environment by introducing regulations regarding the control of admitted vehicles for sale. The emission standards in individual countries are subject to ever more restrictive regulations. What are the current regulations in the emission standards in the EU? And what can be introduced in the future? It’s worth taking a look at the rules in force. In the result you do not become a victim of a smog alert.
What is the euro standards about?
Euro 1, 2, 3
European emission standards is the norm, which applies to limit emissions from cars in the European Union. Solid particles, nitrogen oxides, sulfur oxides, carbon dioxide – all this is covered by the concept of exhaust emissions. Their maximum amount was set with the introduction of the Euro 1 standard in 1992. Two more standards, namely the Euro 2 and the Euro 3, did not make such a big confusion among the producers. Although they could have made it clear that in the future we will need to look at particulate matter more closely. They only showed that cars with a gasoline engine can have more carbon dioxide emissions, while vehicles with a diesel engine have nitric oxide.
The Euro 4 standard, in force since 2006, has started a real revolution. Carbon dioxide in gasoline vehicles was reduced by more than half – from 2.3 g / km to 1 g / km, and in Diesel engines from 0.64 g / km to 0.5g / km. Thus, nitrogen oxides changed, from 0.15g / km to 0.08g / km in gasoline and from 0.5g / km to 0.25g / km in Diesel.
Euro 5 and 6
Another norm – Euro 5, in force since 2011, did not bring any major corrections. Carbon dioxide remained at the same level in gasoline and diesel engines. It is slightly reduced nitrogen oxides to 0.06 g / km and 0.18 g / km, respectively. Only one issue has changed radically. A restriction has been introduced for solid particles in diesel – from 0.025 to 0.005g / km.
The Euro 6 standard currently applies, introduced one innovation. Nitrogen oxides in diesel cars have reduced their permissible concentration to 0.08 g / km. It should be noted that the Euro 6 standard reduces particulate emissions by 97%. In turn, carbon dioxide up to 6 times compared to the first Euro 1.
Control of exhaust emissions
Every car authorized for sale in the European Union passes the homologation track. It verifies that all EU regulations regarding environmental protection, safety and compliance with the production date are met. The tests also include laboratory tests that examine nitrogen oxides and particles that do not exceed 100 nanometres.
However, this method is to be changed. It take place in two stages, and the discrepancy between them should not exceed 2.1. Additionally, in 2020, a new stage will be introduced to examine the margin of error (tolerance). The announced changes affect car companies that need to improve their offers of cars sold.
Emission standards in the EU countries
In most EU countries, there are so-called ecological badges or dust badges. The first appeared in 2006 and over time they gain more and more popularity. They are not only confirmation of the fulfilment of individual Euro standards, but also entitle the owners to enter ecological zones.
Depending on the date of the first registration of the car, these are for example (for passenger cars):
• Euro 4 for Diesel 2006-2010
• norm Euro 1-4 for gasoline 1993-2010
• Euro 5 for Diesel or gasoline 2011-08.2015
• Euro 6 for Diesel or gasoline after 09.2015
You can not enter German and Austrian city centres without having a green ecological badge. It is the responsibility of the local authorities to designate the boundaries of the zones. Sometimes they are cities themselves, sometimes regions (eg Tyrol or Burgenland) or even sections of highways.
Usually the zones are permanent. But in France we will find zones depending on weather conditions (ZPA). There restrictions are in force during the period of increased air pollution. Therefore, being on the Seine, it is worth following local messages.
Each country also sets its own badges and their scale:
• France – 6-levels Crit-Air
• Austria – 6-levels Umwelt-Pickerl
• Germany – 3-levelsUmwelt-Plakette + Blaue Plakette
• Belgium – 1-level REG-Certificate
• Denmark – 1-level EcoSticker
• Spain – 1-level Distintivo Ambiental
• Czech Republic – 1-level Emisni Plaketa
Taking into account the fact that every new euro standard introduced many changes in recent years, we should not expect a reversal of this trend. Emission standards in the EU will change again and again. Especially that society and the European Union are becoming more and more pro-ecological. Therefore, it is not worth combining and exposing yourself to unpleasantness associated with excessive amount of fumes.
The more that there are ways to prevent this. For example, it is enough to have a good quality particle filter and to keep the exhaust system in good condition.
The fight against smog has recently become a common topic in many countries. Therefore, if we see excessive smoke from the car’s exhaust pipe, we should not ignore it. It has a negative impact on the environment. Besides, it may indicate some defect in the catalyst, DPF filter or another element of the exhaust system, or even greater defects, including the engine. A badly diagnosed fault can cause unnecessary and over-the-top repair, which will cost us a lot.
Smoke from the exhaust pipe, diagnostics by color
The colour and smell of smoke often allow us to diagnose a problem. Therefore, anything that comes out of the vehicle’s exhaust pipe cannot be underestimated in excessive amounts.
Blue smoke from the exhaust pipe
One of the most characteristic is blue smoke. Many drivers are terrified at seeing such smoke from the exhaust pipe. Rightly, you should not underestimate the signal that the car gives. When it appears at the morning launch of a car, it suggests burning oil in naturally aspirated engines.
More exactly it indicates to the wear of the elastics/valve seals. The heated engine acts as a sealant, while the cold one causes the droplets of oil to flow into the cylinder, then the blown oil flows out the exhaust pipe. The occurrence of smoke during the increase of the engine’s rotation is usually nothing but destroyed rings. During the addition of gas, the pressure is very high. After some time, the piston may not maintain its tightness, and as a result, the oil will get into the combustion chamber.
Cars equipped with a turbocharger can also experience a blue smoke sign. This condition occurs in the event of a leak. The oil gets then by blowing it together with the air. In this case, it is difficult to determine whether it is a turbine defect or piston rings.
White smoke from the exhaust pipe
White smoke, in turn, does not always indicate any problem. If after starting the engine in the morning white smoke appears, it is possible that it is water vapour, odourless, transparent. Unfortunately, another strong white smoke from the exhaust pipe does not catch up. Then another element comes to the combustion process — water. The standard diagnosis, in this case, is the gasket under the head. However, it is not always set correctly. Car owners who have an EGR cooler (exhaust gas recirculation valve) should take this into account. You can perform a test on the content of exhaust gases in the cooling system. When it comes out positively, prepare for higher costs. It is not enough to just replace the gaskets and perform a number of other tasks like planning, assembly, new timing.
Black smoke from the exhaust pipe
Another one is black smoke, which does not surprise anyone and is mainly assigned to cars with a diesel engine. Very often this happens because driving around the city causes driving below the revolutions of the turbocharger activation. When the black smoke from the exhaust pipe is still emitted after the gas is added, it is the result of inaccurate fuel combustion, i.e. incomplete combustion.
Black fumes can also have a connection to the injection system. This is when faulty injectors or exhaust gas cleaning systems are involved. Vehicles with combustion engines that supply petrol less frequently, but may also experience black smoke. It is possible that the engine then gets too much oil. The key may be a catalytic converter or a DPF filter because they stop the amount of soot being excessive. You need to be aware of the situation that the oil burned in the combustion chamber is the result of the failure of the cylinder head or bottom. At that moment it is worth answering whether the repair will pay off. An important tip is also the use of the correct oil, a simple thing, but sometimes neglected.
The last thing that can be responsible for the emission of black smoke is chip tuning. What is that? It is an improvement of the engine parameters, through interfering with the computer software that controls its work. This is possible because car manufacturers often leave a good deal of stock in terms of parameter adjustment. After overclocking the parameters may damage components such as the crank — piston system, gearbox, turbocharger, clutch, injectors or driveshafts. Catalyst and particulate filter are also exposed. A higher increase in exhaust emissions is observed.
Grey smoke from the exhaust pipe
One more colour of exhaust gases is possible — grey. Most often appearing immediately after starting the engine. The cold engine is then in the so-called suction process. It supplies a rich mixture to the combustion cylinders. If this condition persists for a long time, the engine temperature sensor is most often to blame.
That is why it is important to know what the colours of the smoke from the exhaust pipe mean. Thanks to this, it is possible to save not only time to find the cause of the fault but also money.
A flexible exhaust connector is a small but essential part of the exhaust system. Choosing the right flexible connector will also protect other exhaust components, such as the catalyst, from too fast wear out and reduce the amount of vibrations generated by the engine.
What is a flexible exhaust connector and how does it work?
The flexible exhaust connector is also called the vibration damper. It consists of four layers – two main bellows, outer braid and inner braid or pipe. The main bellows are corrugated tubes that reduce vibrations. A purpose of the braid is to increase flexibility and protect against weather conditions.
The method of assembling the inner braid into the bellows is important. A good quality flexible connector ensures a constant flue gas flow diameter.
The vibrations that the motor produces are transferred to the following components of the exhaust system. The flexible connector is installed behind the exhaust manifold. It is a shield that eliminates some of the vibrations. As a result, further elements – catalyst, silencers and exhaust pipe – are no longer exposed to such high stresses.
What material is the flexible exhaust pipe connector made of?
The flexible connector should be made of high quality SS 304 steel or higher. This guarantees good resistance to vibrations, but also corrosion and high flue gas temperatures (approx. 600-700 °C). This element of the exhaust system will survive up to 4-5 years without any problems.
There are also worse products on the market. Those with a smaller admixture of nickel are more stainless, but also stiffer and less tolerant of vibrations. Another problem with low-grade steel is the quick rusting process. The lifetime of such flexible connector may be even not longer than 3-4 months, especially in countries with variable weather, i.e. where there is heavy rain or snow.
Why is a flexible exhaust pipe connector so important?
As long as the exhaust connector is well-matched and works, everything is fine. Trouble starts when it begins to fail. There may be several reasons:
- it is incorrectly mounted
- made of poor steel, so too stiff
- it just used up
At low-quality steel connectors, a frequent problem is shrinking internal braid, which can reduce the light flow by up to 30%. This, in turn, has an effect on less efficient exhaust emissions, and hence a decrease in engine power.
The shaky motor, which is not suppressed by the elastic connector, transfers the entire load to all parts of the exhaust system. The worst situation is for a catalyst that is not designed for these operating conditions and is closest to the exhaust manifold. As a consequence, the lifetime of the catalyst is reduced, but also silencers, exhaust pipes, handles and hangers.
Last but not least, the acoustics of the car are equally important. One of the first symptoms of abrasion of a flexible connector is knocking under the chassis. This has influence on lower driving comfort and lower driver concentration. And the damage can be done by accident – by hooking a high curb or a stone or gravel spatter from the tires.
Directional or typical connection?
There are two-way and unidirectional connections. The former operate independently, in which direction they are mounted. A directional connectors have a blue border on the exhaust side. The difference is in the arrangement of braid and parameters.
What to look for when replacing the flexible exhaust pipe connector?
If we purchase the connector on our own, we must first measure the length and diameter of the vibration damper. It is best if the measurement is very precise, eg with a caliper. It would be an unpleasant surprise if the new connector turned out to be a few millimeters too short.
Fortunately, this element of the exhaust system is most often universal and fits every brand and model. The length of the flexible connector varies between 60 and 350 mm and the diameter between 38 and 90 mm.
Of course, dedicated vibration dampers are produced for individual brands. We would install special elements in Citroen C5, Audi A4, A3 and A6, Volkswagen Passat and Golf, Renault Laguna, Megane, Thalia and Scenic, Fiat Palio, Punto, Seicento and Siena, Seat Cordoba, Leon, Toledo and Ibiza, Skoda Octavia, Volvo S40 and V40. They have a flange, on the one hand, which eases assembly.
The DPF filter has been introduced for cars with a diesel engine and some with a petrol engine to protect the environment from solid particles’ emission. Unburnt ash and soot are deposited in the filter channels, and cleaner exhaust gases get out. However, the filter capacity is limited, and after about 300-600 kilometres travelled, the filter clogs up. When forced firing is not enough, the car owner faces a classic dilemma — replacement or regeneration of the DPF filter?
Automatic combustion and fuel additives
Typically, the pressure gauge in the filter signals to the computer the need for self-firing. The combustion chamber gets a larger dose of fuel, and thanks to the higher temperature of gases (about 550 deg. C) the soot is burned out. Some advanced DPF filters with an additional injector also dispense fuel directly to the filter. Unfortunately, oil ash does not burn out, and for self-cleaning to occur, you need to drive at a higher minimum speed for 10-15 minutes.
What if we only travel in the urban cycle and do not achieve the speed needed for automatic burnout? There are preparations for filtering on the market. They can be poured directly into the tank or into the filter, after removing the lambda probe. They lower the temperature needed to burn soot. As a result, more solid particles are burnt. Manufacturers recommend using them every three thousand kilometres. However, this is not a permanent solution, but only an inevitable postponement. In the first place, the control lamp on the dashboard will light up. It must not be ignored.
Types of DPF filter regeneration
There are several types of restoring the filter to the correct capacity. Mechanical and chemical regenerations are the most popular and relatively cheapest compared to the necessity of exchange. In addition to forced firing, it is always necessary to dismantle the filter during a renovation. The service technician also evaluates whether the structure of the insert is not damaged, for example, cracked or fused.
There are services that offer forced firing, but the filter cannot be too full. An external computer connected to the engine maintains a speed of about 3,000 revolutions per minute for half an hour. In the event of failure, additional restorative preparations may be used. After this treatment, it is necessary to change the oil. The cost of this regeneration is about 150-200 PLN plus a new oil. It should be remembered that forced combustion does not remove ashes.
Thermal and ultrasonic regeneration
Here it is necessary to disassemble the filter. In thermal regeneration, the cut cartridge is subjected to high temperature — about 700 °C for about 8 to 48 hours. When the process is finished, the filter is welded.
Services using the second method let special chemicals into the cartridge or immerse the filter in water. Under the influence of ultrasound, air bubbles or preparations dissolve impurities. The regeneration process is the longest possible and takes about 12-24 hours. The cost of the service is about PLN 400-500. These methods are not very popular and reputable.
Chemical regeneration / rinsing with water / hydrodynamic method
Using the product for cleaning fireplaces and ordinary pressure washer, we can at best damage the DPF filter. It is better to go to a station where regeneration takes place on a similar basis but under strictly controlled conditions. The clogged filter is placed in a special device connected to the measuring apparatus. Water with a special washing gel is passed through the ceramic insert, first the reverse and then in the direction of the exhaust gas flow. A pressure of the liquid is strictly controlled. The clean filter is subjected to drying at a temperature of about 90°C and cooling. A cost of hydrodynamic regeneration is about PLN 400-500 and gives the best results. Rinsing with water removes approx. 98% of sediments and lasts about an hour.
Replacing the DPF filter
Sometimes regeneration does not fulfil its task or the filter is damaged. Then you have to replace it. A home budget before a large expense can protect the purchase of a replacement filter from a reputable company, instead of a much more expensive original part. The cost of the replacement depends on the brand and model, usually fluctuating between PLN 1,500 and 2,500. We should pass it around 100-150 thousand kilometres without problems.
Buying a used filter always carries a risk. We do not know who and how he cared for it, what course it actually has or is well cleaned. Deciding on the original part for the exhaust system, however, you have to reckon with the costs. Here the price list also depends on the brand — the cheapest about 500-700 PLN, Fiat about 2,500 PLN, Ford, Mercedes about 5000 PLN, BMW, Volvo about 6000 PLN, VW Golf about 8000 PLN, Mitsubishi about 10,000 PLN. Therefore, it seems reasonable to buy a new replacement part, from a reputable company. With the new filter, the car will travel about 150-300 thousand kilometres without problems.
Replacement or regeneration of the DPF filter
Regeneration is much cheaper than replacing the DPF filter. Using the hydrodynamic method of rinsing with water, we get the filter almost like a new one. Then the exchange will be necessary only in case of damage or melting of the cartridge.
Activities of environmental protection began to be undertaken in the United States in the 1960s. The first DPF filter was installed in 1985 in the American Mercedes W126. Unfortunately, the technology was not well-developed at that time, so after two years the idea was abandoned. The reasons were the low efficiency of filters and the frequent need for extra trips to burn soot. Today, technology has gone ahead. So how does the DPF filter work?
How does the DPF filter work?
The ideal situation is when the entire fuel dose is burned to give water vapour and carbon dioxide. However, a car is not a laboratory. So by-products of combustion are carbon soot (carbon oxides) and coal itself, solid particles, nitrogen oxides and hydrocarbons. They used to go directly to the environment. Today they have to go through the DPF filter or re-burn thanks to the ERG valve and then filtering.
The filter itself looks like a catalyst and is part of the exhaust system. At the inlet and outlet there is a special pressure gauge. On the basis of the pressure difference, it assesses the degree of clogging of the filter and, if necessary, starts the self-firing process. Depending on the driving style, this usually takes about 300-600 km. Then it is necessary to drive at a constant speed of 60-80 km / h for about 10-15 minutes.
Inside the particle filter has a ceramic cartridge. It consists of a series of channels. They are alternately closed from the inlet or outlet side. The flue goes to them, the soot and combustion products settle, and the cleaner exhaust gases pass to the neighbouring channels and travel towards the exhaust pipe.
In which cars do not the DPF filter exist?
In the past, no particulate filter was installed or it was done at the owner’s request. All cars produced after 2010 must comply with Euro 5 standards, and thus have a filter. During the transitional period, lower standards, like Euro 4, were also acceptable.
From 2007 to city centres in Germany, and from 2015 in Austria, you can enter only with the “green sticker”, meaning the Euro 4 standard. For models that did not meet this standard, the solution was to install a DPF filter not integrated with the computer. It was cheaper to install, but it did not support automatic regeneration. As a result, after the clogging, the filter had to be replaced each time.
When buying a used car it is worth paying attention to the approval plate. The number in the square determines the degree of pollutant emission. The value 0.5 means the existence of a filter, value 1.2 and more – no filter. Then you should be aware that adding this element will be necessary.
What is the difference between DPF and FAP?
There are several different types of particulate filters. In older models, a simplified DPF filter was fitted, which was not integrated with the car’s electronics. It had to be replaced after each clogging. This is an expensive and troublesome solution in the long run, but it raises the norm from Euro 3 to Euro 4.
The DPF named also as dry filter is the most popular one. We meet him mainly in German brands. It is located near the exhaust manifold. There is a high temperature there, and a slightly larger portion of fuel fed in the exhalation phase is enough to burn soot.
In turn, French cars usually have a wet filter known also as FAP. A special liquid (Infineum or Eolys) is added to the filter, which reduces the temperature required for firing. As a result, self-regeneration is more efficient. In operation, this is the cheapest solution, although it is necessary to regularly refill the liquid. Corporations are slowly moving away from the concept of FAP filters. Eg Peugeot in the series with BlueHDi engines has already put on classic DPF filters.
There are also advanced diesel particulate filters with an additional injector. They can be found, for example, in Renault with a 1.5dCi engine or Toyota with a 2.2 D-CAT engine. At the right moment, a portion of the fuel is injected into the filter, which burns the excess soot and sediments.
Not only the diesel engine is fitted with an exhaust gas cleaning device. Cars fuelled with petrol with direct fuel injection increasingly have a GPF filter. This is due to a much higher ignition temperature. Is this a good way to develop gasoline engines? Opinions are divided.
Is a particle filter needed?
American cities in the 1950s, in the era of massive development and popularity of cars, faced a real environmental problem that was being solved. Similar efforts were made by European constructors. The result is ERG valves and particulate filters that significantly reduce the emission of harmful substances into the air. Thanks to the technological progress and a wide range of parts and exhaust fitting accessories, we have significantly reduced the impact of exhaust gases on our planet. Restrictive standards are not only a whim of officials, but a real need. Therefore, even people with older specimens should consider installing a DPF.