Denoxtronic 3.1 – Urea Dosing System for SCR Systems

Market Facts

  • Over the next eight years, the number of vehicle applications equipped with Bosch Denoxtronic systems will see growth in the millions
  • Denoxtronic 3.1 projected growth 210%
  • Many systems are starting to come out of OEM warranty, providing opportunity to capture this segment

Customer Benefits

  • Reduction of nitrogen oxide emissions by up to 95%
  • SCR control strategy and AdBlue/DEF Dosing System from the same supplier
  • Minimal emissions: adherence to Tier 2 Bin 5 (USA)
  • Enables fuel-saving and subsequently CO, reducing engine design. The additional cost of the SCR system can be recouped relatively quickly due to this fuel consumption benefit

Components of the Denoxtronic 3.1

  1. Supply Module on AdBlue/DEF Tank Unit
  2. Dosing Module
  3. Control Unit


In order to reduce the environmental burden of toxic substances emitted by motor vehicles, the worldwide limits for missions have been continuously reduced over the past years. The emission limits can be complied with via engine-internal combustion measures or via the treatment of the exhaust gas. Engine-internal combustion measures can lead to conflicts when balancing nitrogen oxide (NOx) emissions, particulate, fuel consumption and noise targets. Exhaust gas treatment helps to resolve these target conflicts while at the same time reducing fuel consumption and CO2, output.

Modern passenger-car diesel engines, with a Common Rail System, have NOx, raw emissions that are 96% lower than those of typical diesel engines of 1990. The SCR (Selective Catalytic Reduction) system with the Bosch Denoxtronic reduces these NOx, raw emissions by up to a further 95%. To do this, the reduction agent AdBlue/DEF is injected into the exhaust gas flow. The Urea Dosing System Denoxtronic 3.1 developed by Bosch has been in series production at several OEMs since mid 2008. Application of the Denoxtronic 3.1 already enables compliance with Tier2 Bin5 limits.

Possible Applications

The Denoxtronic 3.1 is primarily designed for use in passenger cars and in the light-duty segment. Further possible applications exist in the off-highway segment for engines in the range 56 … 100 kW. The OHW requirements must be checked from case to case.


Future Denoxtronic developments will concentrate on optimization of the spray, higher operating temperatures and a greater degree of robustness when the system freezes as well as on cost-optimized solutions.

Functional Principle

The SCR procedure involves mixing the reduction agent AdBlue/DEF. a 32.5% solution of urea in water. with the exhaust gas. With the help of a pump integrated in the Supply Module, the AdBlue/DEF is fed from a tank to the
Dosing Module and from there into the exhaust gas upstream of the SCR catalytic converter. There the urea is converted via thermolysis and hydrolysis into ammonia required for the further reaction. In the SCR catalytic converter, the ammonia reduces the exhaust·gas nitrogen oxides into water and nitrogen.

The electronic control can be integrated into the Engine Control Unit (ECU) or, alternatively. into a Dosing Control Unit (DCU). In the latter case, the Dosing System is supplied with the current engine operating data via a CAN (Controller Area Network) bus and, in addition, processes all the sensor and actuator data requ ired for the Dosing System. The dosing strategy is applied to match the quantity of reduction agent precisely to the engine operating point and to the
properties of the catalytic converter for maximum nitrogen oxide conversion.

Technical Features

Dosing Quantity (min./max.)15… 3, 120 g/h @ 5 bar
AtomizationLess than or Equal to 100 Sauter Mean Diameter
Dosing Readiness:
– After start up
– Defrosting time (-15°C)

Less than or Equal to 30 s
Less than or Equal to 20 min
Ambient Conditions:
– Supply Module/Tank
– Dosing Module
– Short Term (<10 min.)
(with air cooling)
-22…284°F (ambient temperature)
320°F (< 100 h over lifetime)
LifetimeEquals B10:
300,000 km/6,000 h
Operating Voltage12 V
Electrical InterfacesBosch standard connectors, full software support
Injection line between Dosing & Supply ModuleLength 1,000…5,000 mm
Emission TargetEuro 6, T2B5
Technical Features

Jimmy Finch

Dallas Branch Manager, M&D Distributors

Jimmy Finch has over 33 years of experience in Diesel Engine Sales, Service and Repair. His experience started early in life at Texas Fuel Injection Service (an early acquisition of M&D) as a job with a means to an end. Somewhere in that 33 years this job turned into a fulfilling career. He started in the injector clean up department and has held practically every position leading up to his current role as Branch Manager of the Dallas, Texas location.

In his spare time, Jimmy enjoys spending time with his wife of 24 years, Priscilla. They are currently getting ready to make their way into the empty-nesters stage of life. He also enjoys the occasional hunting trip with friends and family and chasing down potential customers by the names off their trucks.

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