Urea consumption for Mercedes. Urea for diesel - what is it? How much is approximately spent AdBlue reagent in a car?
Ecologists from all over the world are sounding the alarm: 65% of harmful emissions in the atmosphere are caused by motorists. The academic community, in turn, is trying to convince producers: there is an overdue need to develop a new system that will reduce the% of emissions and stop harming the environment. In our country, special environmental standards were introduced, each of which had its own limitations.
And electrification will be one of the pillars on which to build to overcome the next challenge. Carbon dioxide. Another gas. This is due to the greenhouse effect and global warming. It is present naturally. It is sent, for example, to people who breathe and plants at night when the process of photosynthesis is canceled. In vehicles, the catalyst is formed as a residue in carbon monoxide removal processes.
Nitrogen oxides. They go hand in hand with gas oil, because gasoline produces them in almost insignificant quantities. They also enter the atmosphere in the form of gas. They refer to acid rain and beret covering cities. Particles. They also depend mainly on diesel fuel. They can be visualized as a black cloud, which displaces some old diesel during acceleration. For this reason, Euro 6 includes only additional reductions: from 5 milligrams per kilometer to 4, 5, the same maximum set for gasoline cars.
| Environmental standard (regulates the content of harmful substances in exhaust gases) | Introduction date | ||
| European Union | Russia | ||
| Trucks | Fuel | ||
| Euro 1 | 1992 | - | Until 31/12/2012 |
| Euro 2 | 1995 | September 2006 | |
| Euro 3 | 1999 | 01/01/2008 for imported or produced in Russia | Until 31/12/2014 |
| Euro 4 | 2005 | Since 01/01/2013. Euro 3 issued before 31/12/2012 allowed | Until 12/31/2015 |
| Euro 5 | On new cars 01/10/2008 | On all imported 01/01/2014 | From 01/01/2016 |
Euro 5 standard requirements
- NOx 0.06 g / km (2.0 g / kWh)
- WITH 0.8 g / km
- SN 0.05 g / km (PM 0.02 g / kWh)
- The mileage of the car, at which environmental requirements are to be maintained, is 160,000 km.
Requirements of previous standards (Euro-1, Euro-2 and Euro-3) were achieved by:
- simple improvements to the exhaust tract (particulate filters);
- structural changes in the fuel supply system (pump nozzles, individual for each cylinder, high-pressure fuel pumps up to 2000 bar, Common Rail fuel rail);
- gas distribution improvements;
- computer control enhancements (multipoint guns and multiple injection phases).
The next Euro 4 standard was provided by the installation of the SCR system. Manufacturers such as Volvo, Scania and MAN, have resolved the issue of compliance with the EGR recycling system. Harm to the environment was minimized by cooling part of the exhaust gases and returning them to the intake manifold. Consumption rose by about 3%. However, the engines of these Euro-5 cars also remained urea.
A volcanic eruption, among other natural phenomena, also releases particles into the atmosphere. And they are generated, because part of the fuel does not burn inside the engine and ends with the release of exhaust gases. They can cause respiratory conditions.
Weary, and with limited consumption. We launched our test section of industrial cars, in which Enrique Sánchez Parrondo will show us the most effective side of these “asphalt monsters”. The urea solution injectors were improved to prevent stuffing, which sometimes affected the original models. The new 12, 7-liter and 6-cylinder units maintain a solid reputation established by its 11,7-liter predecessors. They have a diameter of 9.3 liters. But with a longer race.
SCR system
SCR system - “Selective Catalytic Reduction” - otherwise selective catalytic reduction. It is designed to reduce the level of nitric oxide, which is contained in the exhaust gases. Neutralization (reduction) reaction occurs selectively: decreases in exhaust gas only nitric oxide (NOx) content!
Undoubtedly, one of the strengths of this truck, since the answer is fast, accurate and corresponds to what you are asking for an accelerator. Electro-hydraulic drive for automatic clutch mounted on the gearbox. The automatic clutch works independently of the driver’s ability and is programmed to engage with the lowest engine speed. Therefore, if necessary, the engine speed increases to start the car without jerks. The engine management system ensures that the clutch never slips during a shift maneuver, but is used only to disconnect the gearbox from the engine.
This compound is converted to nitrogen (N2) and water (H2O). To this end, a reducing agent is continuously injected into the gas stream in front of the catalyst (this is an aqueous solution of urea, which freezes at -11 ° C). Urea is in a separate additional plastic tank. A 50 liter tank is filled to 80%.
AdBlue urea consumption is 4% of the total diesel consumption of Euro-4 and about 6% of Euro-5. This is 1.5 - 2 liters for every 100 kilometers. When heated to 250 ° C, the reduction catalyst reaches a working t◦. Note that in the city mode it is practically not achievable. Next, the engine control unit will receive data on the exhaust gas t◦ before the recovery catalyst from the t◦ sensor.
These functions effectively protect the clutch and other components of the kinematic chain from mechanical damage. The five-point retarder has an inlet for the engine attached to the latter. It is very soft and stable when stored in a descent, fully synchronized with the gearbox, without the help of the service brake and engine brake, there are no problems to maintain the desired speed during descent. If you need help with engine braking, if the speed needs to be significantly reduced, the engine brake is 261 kW at 400 rpm, but only with this help the service brake is needed for circulation of the population or with retention.
Urea will be injected if:
The catalyst reached 250◦ (working t◦);
A sufficient amount of liquid urea for injection is provided.
Injection will stop if:
Exhaust gas flow is low (at idle);
T◦ of exhaust gases is reduced too much, and the working t◦ of the catalyst is not reached.
AdBlue urea solution is an aqueous urea solution of 32.6%. Under pressure of 5 bar, it is pumped through a pump through a heated pipeline to the nozzle. The latter is controlled by the engine control unit and injects a metered amount of urea into the exhaust gas pipe. Received urea picks up the flow of exhaust gases, so that the first is evenly distributed by the mixer.
The system helps the driver by applying greater braking force and better utilization of the available friction. From the above remarks and in accordance with the results obtained, of course, that such a unique driving, not everyone can afford it, either within a few hours of driving, or within a few hours of rest. Of course, a 31 cm tunnel with an engine is not very convenient when accessing a bed or another part of the cabin, but the holes in the interior are sufficient for the national route, provided that not four or five a week away from home, in this case, if we are small .
1. In the area between the reducing catalyst and the urea nozzle (hydrolysis area), urea decomposes into carbon dioxide (CO2) and ammonia (NH3) - it goes further to the reduction of nitric oxide. This reaction occurs due to thermolysis (decomposition of the compound under the action of heating) and hydrolysis (decomposition of the compound under the action of water). After urea injection, the water evaporates first. During thermolysis, an aqueous solution of urea (reducing agent) will decompose into ammonia and isocyanic acid: CO (NH2) 2 b NH3 + HNCO (urea b ammonia + isocyanic acid).
The bed is comfortable, eliminating missing access problems. It is strange that a typical opening for a large water bottle next to the driver is replaced by two openings for small bottles, and if you want to carry a large bottle, it should be at the door, but no compartment is defined for it. Easy to reach by driving, because it has a lot of settings on the seat and on the steering wheel. From the driving position, you have all the controls within easy reach. The use of cruise control and retarder is very intuitive and easy to use, which makes driving easier at certain times.
2. The hydrolysis reaction is the reaction of isocyanic acid with water contained in the exhaust gases. As a result, another ammonia molecule and carbon dioxide arise: HNCO + H2O b NH3 + CO2 (isocyanic acid + water b ammonia + carbon dioxide).
3. In the catalyst, ammonia reacts with nitrogen oxide. As a result, nitrogen and water are formed. The efficiency of the SCR system determines the NOx sensor (sensor of nitric oxide content).
The front umbrellas are waving and, perhaps, somewhat small, so at certain times of the day they do not perform their function as we do. The side visor has the same system, but here it is possible to equip the curtain, which is more convenient to adjust the height. Visibility is good, and with rear-view mirrors you don’t lose any detail about what is happening outside.
These large doors improve access to storage compartments. In addition, if it is not fully closed, the driver is warned about the warning lamp on the dashboard. All information is in your hands. On the toolkit screen, if you want to follow the course of your route while driving, breaks, consumption, average speed, etc. you have all the data, the screen is the most complete and easy to use on the market.
SCR system shutdown: is it possible?
Without consequences for the SCR machine can not be disabled. Otherwise, you will have to face the following problems:
1. The engine control unit will generate an error (when the power is off to the SCR system, the CAN bus and individual sensors). Engine power will be limited to 60%, and consumption will increase to 40 l / 100 km.
Tractors and combines Cranes Machines for ports and airports Excavators and machinery used in mines or in the construction sector. Known in the agricultural sector as a leader in the field of mineral fertilizers. This degree of purity is provided by more thorough production and distribution processes than those used in the production of agricultural urine.
These processes justify a different sale price. We have a full range of solutions for tractors and machinery. Check in advance if you can refuel your tractor or off-road equipment at such sites, since you can usually only fill trucks and buses with trucks. We know their working conditions, and because of this we have developed a wide range of equipment to suit your needs, whether in the fields, in farms or on construction sites, even if you have little storage space or you do not have electricity.
2. It is also impossible to mix the solution on your own. At the exit is formed not entirely clear liquid.
3. instead of urea - aqueous distillate.
4. The reagent filter is AFTER the pump, not the BEFORE. If the filter is clogged, the pump will squeeze the reagent into the case of the block - pump where the processor is located. What happens next, we think, is not worth explaining.
It also depends on the model and engine type. Different suppliers also offer different strategies and approaches to the market. Because of the required quality, it is produced in a way that is much cleaner than that used in agricultural fertilizers.
That is why it is sold at a completely different price. In addition, urea production requires a lot of energy; Mostly natural gas. Variations in the price of crude oil, natural gas and ammonia have a direct effect on urea prices. Warning: Do not use urea solution. First of all, do not use urea, which is produced for fertilizer, as it will not be of sufficient quality for your engine and can lead to very expensive failures.
5. installation of an emulator that feeds into the engine control unit averaged sensor readings and simulates a pump and a level sensor or simulates the freezing of the system. The pump itself will stand in the tank will be empty. The machine will almost believe in the health of the system, therefore, does not activate emergency mode (ingine spesial limited). But ... an error about the incorrect operation of the system will still burn, and the flow will be increased. After all, the EGR system has its own separate NOx sensor. He recognizes your cunning plan and limits the flow of fuel (not critical). The drop in capacity will not be critical, but the expense will grow unnoticed. The same will happen in case of imitation of the system freezing. The car, or rather, its electronic brains will see a discrepancy between the readings from the street air sensors t◦.
It is very different from urea, which is used in natural fertilizers, which is not so clean. New regulations set stricter emission limits for heavy duty diesel vehicles. To comply with them, vehicles with new technologies and low-sulfur diesel are required. Here we reveal all doubts.
Ecological benefits for society. This requires changes in engines, new exhaust after-treatment systems and low-sulfur diesel fuels. How long can Euro 3 cars be sold? What changes will be applied in vehicles to meet new emission limits? The law requires new technologies for trucks and buses. With this system, part of the exhaust gas is returned to the inlet, reducing the combustion temperature from the removal of nitric oxide.
CONCLUSION: you will save 4% fuel consumption. But at the same time, you definitely lose the guarantee and remain with vague prospects for the engine. Advice from experienced drivers of dump trucks - do not experiment, it will be more expensive for you!
Currently, there is an extensive environmental campaign in the EU countries. Millions of cars around the world emit large amounts of harmful substances into the atmosphere every year. Of course, in the city the refusal of movement by car is hardly possible, but reducing the damage from exhaust seems to be a feasible task. To this end, relevant regulations and standards have been developed. But from year to year they only become tougher, which has become a real problem for car companies. This led to the emergence of AdBlue urea and SCR technology.
In addition, the exhaust system requires a more complex turbocharger system and a diesel particulate filter. As for the material in the form of particles, the pollutant decreases during combustion by the engine itself. What is the best technology? Both technologies have advantages depending on the application of the vehicle. Each manufacturer has chosen the most suitable for its products and sets its strategy, taking into account mainly the costs and operating conditions of the truck.
To cope with new emission limits, the sulfur content must be significantly lower for the gas treatment systems to function properly. So what are the changes in diesel? The main change is the reduction of sulfur content. Can a new low sulfur diesel be used on older cars? Yes, they also offer advantages: reduced emissions of material particles, less wear on rings and cylinders, in addition to longer life and less wear on lubricating oil.
Initially, car concerns tried to change the system of supply of diesel fuel and gas distribution in such a way as to reduce the volume of hazardous compounds in the exhaust gases. However, in the future, this task is much more complicated. But a selective catalytic neutralization method came to the aid of manufacturers, in which special equipment is installed on the machine, which is responsible for injecting urea into the exhaust system, as a result of which the negative impact of exhaust gases on the environment is greatly reduced.
In principle, it is completely inexpedient, because in addition to increasing the amount of emissions, it will impede the catalyst and filter. Will it be easy to find new fuel in the whole country? It is a urea-based liquid reagent specific for use in the automobile. It is introduced into the catalyst using the necessary dosing system in vehicles with Euro technology.
The catalyst produces a chemical reaction that converts nitric oxide to nitrogen and water vapor, which significantly reduces pollutant emissions. How much will be estimated consumption of this product? It will be available in the main networks of service stations throughout the country, in official representative offices and specialized seminars throughout the country. It is harmless and can be processed without problems. It is odorless, does not irritate the skin, is not explosive or polluting.
Why urea is needed
AdBlue product is a special reagent used in all diesel engines that meet Euro-4 and Euro-5 standards and include a cleaning SCR system. It is an aqueous solution of urea, which plays a major role in the process of catalytic neutralization. Thanks to its use, it becomes possible to obtain an environmentally safe exhaust, prolong the engine operation period and increase its efficiency.
Do not store in metal containers that may oxidize. It is important to read and follow the instructions for use and processing listed on the product packaging. Depending on the type of vehicle, the engine may lose 25% or 40% of its torque until the tank is properly filled.
The engine will work only with a product made in accordance with the specifications. This equipment is mandatory in Euro 5 vehicles and is constantly monitored, having the ability to register more than 200 possibilities of failure, especially those associated with the subsequent processing of gases.
Now let's talk about why urea is needed for trucks. Note that at present, almost all trucks are equipped with SCR-converters, thereby increasing the operational characteristics of the machine itself and its motor, and engine elements receive protection from carbon. Urea is poured into a dedicated tank located next to the car engine.
As a rule, the volume of the tank is 120 liters. The AdBlue product is quite economical and no more will be needed. This volume is enough for a run of 8 thousand kilometers. The basic principle of the use of this reagent is the accuracy of compliance with the attached instructions and the use of only the original product. It also matters how clean the tank into which urea is poured, and from what materials it is made.
Waste gas cleaning stages
High efficiency of the AdBlue product is based on 2 cycles. At step 1, urea is injected into the stream of exhaust gases leaving the combustion chamber. Due to the high temperature, a chemical reaction is triggered, as a result of which urea is converted to ammonia. At the last, 2nd step, hazardous nitrogen oxides in exhaust gases, through the effects of catalyst and ammonia, pass through an oxidation reaction and are converted into ordinary water and nitrogen — usual and safe substances. Here is a brief description of what makes urea for diesel, why it is needed.
Urea in diesel engines is used to achieve maximum compliance with exhaust gas purity standards Euro-4, Euro-5 and Euro-6. And thanks to the enormous cost-effectiveness of SCR-technology, this product has gained great popularity among automotive companies all over the world.
But for our country, this product is not considered the most suitable, since urea has certain disadvantages:
- AdBlue needs additional refueling, and in Russia it can be purchased far from everywhere, and its quality does not always meet the requirements. At the same time, AdBlue consumption is equal to 5-7% of fuel consumption;
- This product freezes at -11 ° C, so it is difficult to use it in the Russian winter;
- Bad smell from the exhaust system;
- When the AdBlue tank is heated, ammonia vapors appear, irritating the eyes, skin and mucous membranes;
- AdBlu toxicity, its ability to cause chemical burns when exposed to the skin;
- There are too many fakes on the domestic market, so there is a high probability of system failure.
- In the end - it is unnecessary and considerable costs.
Related Articles
