SCR (Adblue) for EURO 5 diesel engines

SCR – exhaust gas aftertreatment system by spraying an aqueous AdBlue solution into the vehicle’s exhaust system to reduce emissions to Euro 5 levels.

The Euro 5 environmental standard has been introduced in European countries since 2009. According to the standard, manufacturers of heavy-duty and other vehicles are obliged to provide their products with a system capable of meeting the norms of harmful substances in the exhaust gases.
Most manufacturers have opted for exhaust gas neutralization (SCR). Often, you will hear terms such as:

  • Euro 5
  • Urea
  • AdBlue

As a rule, when using such names, we are talking about SCR.

The system is installed on all types of cargo and heavy machinery – mainline tractors, dump trucks, buses, construction machinery, industrial engines (diesel generators, etc.), marine engines. In other words, machinery or plant equipped with a diesel engine will be equipped with an exhaust gas aftertreatment system.

The SCR control unit calculates the amount of solution required for injection, taking into account the current engine operation parameters and the catalyst temperature. The calculated amount of liquid is injected through a nozzle or metering module. The NOx sensor monitors the quality of the exhaust aftertreatment. The SCR control unit communicates with the engine control unit via the CAN bus network to obtain information on engine operation.

With the CAN bus, the control units communicate with each other and make requests to change parameters necessary to ensure the operation of the entire system.

For efficient operation of SCR it is necessary to keep the catalyst temperature above 300 degrees. SCR is not able to increase the catalyst temperature to the required value by itself – therefore, to increase the temperature values, the control unit (5) makes a request for fuel mixture enrichment to the engine control unit (8) via CAN bus. This is how the required temperature value is achieved.

SCR system modes

Fuel mixture enrichment

This mode is required to warm up the catalyst and maintain the required catalyst temperature during SCR operation

Torque limitation

Activated in the event of an SCR malfunction. When this mode is activated, the yellow or red SCR fault indicator lights up on the dashboard and the vehicle’s power is limited by 40%.

Idle speed increase

This mode is necessary to warm up the catalytic converter at idle speed. The idle speed will be increased until the desired temperature is reached.

Operation of the neutralization system (AdBlue)

For proper operation it is necessary to maintain a certain level of AdBlue liquid in the SCR solution tank, and special attention should be paid to the quality of AdBlue solution.

Also, the owner of the vehicle or machinery should periodically carry out technical maintenance: replacement of the liquid filter, diagnostics in order to detect malfunctions.

Causes of SCR failure

⦁ Failure of electronic sensors of the system: catalyst temperature, NOx, AdBlue pressure
⦁ Malfunction of electrical circuits of SCR control unit
⦁ Use of low-quality AdBlue solution, which cannot provide necessary aftertreatment of exhaust gases; presence of third-party liquids (e.g. diesel fuel) in AdBlue solution may lead to pump failure, clogging of lines, injector, metering unit.

Any of these faults will result in torque limitation of the engine.

Ways of disabling SCR

The Euro 5 system is thoroughly researched and there are several options on the market to disable SCR Euro 5. Among these options there are quality, reliable solutions, but there are also knock-offs or outdated, ineffective solutions.

Software disabling

SCR is disabled programmatically by making changes to the vehicle’s firmware.

+ is a fairly reliable method of disabling
– not all car brands support software disabling
– on some cars, such as Scania, with software disabling SCR on the display of the car will burn errors, which simply can not be extinguished (in this case, SCR will be completely disabled)
– on some car models (Scania, Renault, Volvo) after programmed disabling may activate the warm-up function, which increases the idle speed.
– implies that the entire SCR periphery is retained on the vehicle.

Disabling by means of an Adblue emulator

A device that simulates the working processes of the vehicle metering system. The emulator works according to complex mathematical models, is connected to the CAN data transmission line and is able to calculate the necessary parameters for correct engine operation: exhaust gas temperatures, amount of harmful particles, pressure and temperatures of the reagent, air pressure and other parameters necessary to prevent errors resulting in torque limitation.

In other words, the emulator replicates with 100% accuracy the actions and operations that the vehicle’s SCR system performs and transmits information about these processes to the vehicle’s CAN data line. No control unit is able to distinguish the operation of the emulator from the operation of a serviceable system.

+ This method applies to all types of trucks and other vehicles
+ Emulator means disabling SCR without any changes in the car operation (fuel consumption, appearance of fault codes or other engine parameters).
+ Possibility to dismantle SCR elements after disconnection.
– High risk of buying a low-quality emulator, which can lead to increased fuel consumption and/or other malfunctions.

Adblue emulators – how to choose?

Nowadays our market is full of counterfeit copies and emulators of Chinese production, installing them on the car is not recommended.

What is the difference between a quality emulator and a copy or analogs of Chinese production?
A quality emulator does not make any changes in the car’s operation, accurately calculates all temperature modes. Such results are achieved due to the constant work of specialist engineers who update the emulator software in time, so that the emulator perfectly fits the engine model.

Copies of emulators are usually copies of high-quality but outdated emulator models. For example, we managed to find on the market emulators with firmware from 2009! At that time this emulator met all the requirements, but nowadays it is hopelessly outdated, such emulator can incorrectly calculate temperature regimes, resulting in increased fuel consumption and errors.

In order to avoid system failures, reduce fuel and repair costs, save your time and nerves, we recommend installing Limpoff emulators. All our emulators, including first generation emulators, are designed and manufactured from European and American components.

We value our reputation and give a 3 year warranty on all units.

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