Tài Liệu Hệ Thống Xử Lý Khí Thải Selective Catalytic Reduction SCR Động Cơ Diesel Audi

Self Study Programme 622 For internal use only Second generation Audi clean diesel Audi Service Training The SCR system - the key to achieving the tougher EU 6-1 (W), BIN 5, Tier 2 and LEV III emission standards Reducing the nitrous oxide content (NOx) in exhaust emissions is a global challenge facing automobile manufacturers, who are required to meet the new statutory limits set by the Euro standard and equivalent international regulations on exhaust emission limits A modern "Selective Catalytic Reduction" (SCR) emission control system utilises the chemical synthesis product of urea (AdBlue®) to reduce NOx emissions In SCR systems, AdBlue® reacts with the NOx emissions to produce water vapour and nitrogen NOx is short for nitrous oxide gases; they occur during the combustion process in diesel engines and are reduced by means of SCR technology '' 1) AdBlue® is manufactured by a solution of a chemical called urea (also called carbamide) in water Urea is a synthetic product which usually is made from natural gas and used in fertilizers, plastics and cosmetics AdBlue® is not made from recycled agricultural products For exhaust gas aftertreatment in the AdBlue® SCR system, the exhaust system requires additional components such as the heated catalyst1), the water-cooled metering valve, the diesel particulate filter with integrated DeNOx catalytic converter and the ammonia blocking catalytic converter AdBlue® is a registered trademark of Verband der Automobilindustrie (VDA) Installed in a limited number of models only 622_023 Learning objectives of this self study programme: This Self Study Programme describes the design and function of an exhaust gas aftertreatment system adapted for the use of AdBlue® reducing agent Once you have completed this Self Study Programme you will be able to answer the following questions: • What is the function of the heated catalyst? • Which new sensors are integrated in the reduction system? • Why does the exhaust gas temperature have to be relatively high? • What is the function of the ammonia blocking catalytic converter? 622_002 Contents Introduction Emission standard _ Audi models based on the Modular Longitudinal Matrix (MLB) with SCR system _ Exhaust gas aftertreatment by an SCR system Basic design (overall system) _ Exhaust systems Introduction 1.6l / 2.0l TDI engine (EA288) _ 3.0l V6 TDI engine 12 4.2l V8 TDI engine 16 Fuel and reducing agent tank Reducing agent tank 18 Audi Q7 _ 18 Audi A6 ’11 and Audi A7 Sportback _ 20 Audi A4 ’14 22 Audi A8 ’10 and Audi A8 ’14 _ 24 Swirlpot in active tank 27 Sensors and actuators System overview (shown using the 3.0l V6 TDI engine as an example) _ 28 Reducing agent pump V437 _ 30 Reducing agent tank sender G684 (level sender) 31 Particulate sensor G784 with control unit _ 32 Reducing agent injector N474 (metering valve) _ 32 Display strategy Overview _ 35 Messages relating to reducing agent fill level _ 36 Fault warnings _ 37 Service Tools 38 Annex Self Study Programmes 39 The Self Study Programme teaches a basic knowledge of the design and functions of new models, new automotive components or new technologies It is not a Repair Manual! Figures are given for explanatory purposes only and refer to the data valid at the time of preparation of the SSP This content is not updated For further information on maintenance and repair work, always refer to the current technical literature Note Reference Introduction Emission standard The emission standard for motor vehicles limits sets out limits for carbon monoxide (CO), nitrous oxide (NOx), hydrocarbons (HC) and particulate matter (PM) and subdivides vehicles thus into emission classes Specific key numbers are assigned and used, for instance, to calculate road tax and to classify vehicles for low emission zones Emission limits vary according to engine type (petrol or diesel engine) and vehicle type They are subject to ongoing tightening within the European region The values are measured in type tests within the driving cycle, and the vehicle manufacturer has to guarantee the compliance with these limits for a specified period of time and mileage This is achieved by in-service monitoring and by carrying out recalls in case of systematic faults Some vehicles are subject to limits on evaporative fuel emissions and mandatory On-Board Diagnostics (OBD) Emission limits from the emission standards European Union USA Japan in % Particulate matter (PM) Nitrous oxides (NOx) Nitrous oxides (NOx) Limits in g/mi Limits in g/mi in % Hydrocarbons (HC) and nitrous oxides (NOx) in % Carbon monoxide (CO) Limits in g/km 622_003 Abbreviations LEV ULEV SULEV BIN 5 Low Emission Vehicle Ultra Low Emission Vehicle Super Ultra Low Emission Vehicle Emission standard for California and other US states The term "BIN" stems from the word "bag"; this is because the exhaust gases are collected in bags during emission tests and analysed There are 10 categories ranging from BIN 10 (highest emissions) to BIN (lowest emisisons) Phase-in dates of EU emission standards for diesel engines New types New vehicles EU EU EU EU EU EU EU EU A F J N Q T W ZA1) from 01.09.2009 01.09.2011 01.09.2011 – – – 01.09.2014 01.09.2017 to 31.08.2011 31.08.2014 31.08.2014 – – – 31.08.2017 – from 01.01.2011 01.01.2013 01.01.2014 – – – 01.09.2015 01.09.2018 to 31.12.2012 31.12.2013 31.05.2015 31.12.2012 31.12.2013 31.08.2015 31.08.2018 – Emission limits EU a EU b EU b EU a EU b EU b EU b EU c OBD standard EU EU EU + EU EU EU + EU 6-1 EU 6-2 1) at planning stage Audi models based on the Modular Longitudinal Matrix (MLB) with SCR system 622_014 A4 ’14 A5 ’14 Q5 A6 ’14 A7 Sportback Q7 A8 ’13 A8 ’14 Engine type 2.0l R4 TDI 3.0l V6 TDI 2.0l R4 TDI 3.0l V6 TDI 2.0l R4 TDI 3.0l V6 TDI 3.0l V6 MPI 3.0l V6 MPI 4.2l V8 TDI 3.0l V6 MPI 4.2l V8 TDI SCR tank system manufacturer Inergy Gen. II Inergy Gen. II Inergy Gen. I Inergy Gen. II Inergy Gen. I Inergy Gen. II Inergy Gen. II Röchling Reducing agent active tank x x x x x x Reducing agent passive tank x AdBlue® capacity 20 litres x 22 litres 17 litres 23 litres x 20 litres 27 litres Reference For information on the design and function of the SCR system in the Audi A3 saloon (USA), refer to Self Study Programme 625 "Audi A3 saloon" Exhaust gas aftertreatment by an SCR system Basic design (overall system) Exhaust gas temperature sender (upstream of oxidising catalytic converter) G448 Oxygen sensor G39 Reducing agent injector N474 (water cooled) Engine control unit J623 Oxidising catalytic converter with catalyst heater1) SCR-coated diesel particulate filter NOx sender with control unit G687 Ammonia blocking catalytic converter Catalyst heater control unit 11) J1021 Components The exhaust gas aftertreatment system comprises the reducing agent tank system together with the water-cooled reducing agent injector, a close-coupled heated catalyst1), an SCR-coated diesel particulate filter and an ammonia blocking catalytic converter located upstream of the main silencers 1) Installed in a limited number of models only Multiple temperature sensors are integrated in the exhaust system upstream and downstream of the turbocharger together with the oxidising catalytic converter, the diesel particulate filter, the oxygen sensor and the NOx sender The exhaust aftertreatment process is monitored with the aid of the various sensors Task of the SCR system In the first stage, emissions and fuel consumption are reduced by minimising friction; in the second stage, emissions are minimised by the exhaust gas aftertreatment system To achieve the EU emission limits, new components, sensors and actuators are used to minimise nitrous oxide emissions in addition to the familiar AdBlue® reducing agent Reducing agent filler neck Reducing agent metering system control unit J880 Swirlpot with reducing agent pump V437 Heater metering line Reducing agent transfer pump V436 Reducing agent active tank Reducing agent passive tank 622_025 Exhaust systems Introduction To meet the requisite emission standards, modern exhaust systems are no longer configured simply as silenced exhaust systems, but as exhaust gas treatment and monitoring systems They comprise: The exhaust systems has the following sensors: • Oxygen sensors • NOx sensors • Differential pressure sensors • Oxidising catalytic converter with/without catalyst heater1) • SCR-coated diesel particulate filter • Ammonia blocking catalytic converter In addition, there are several temperature sensors which monitor the temperature levels in the exhaust system The complex open and closed-loop control functions have been integrated into the engine control unit 1) Installed in a limited number of models only 1.6l / 2.0l TDI engine (EA288) Exhaust gas temperature sender (downstream of diesel particulate filter) G648 Flexible pipe Ammonia blocking catalytic converter, see "Ammonia blocking catalytic converter" on page 11 Exhaust gas treatment module, see "Exhaust gas treatment module with SCR system" on page 10 Engine modifications To meet the EU requirements, the existing 2.0l and 1.6l TDI engines have been upgraded to include the following components: • • • • Variable valve timing High pressure exhaust recirculation Cylinder pressure control system 2000 bar injection system Exhaust flap control unit J883 622_006 Reference The design and function of engines from the Modular Diesel System (EA288) are explained in Self Study Programme 608 "Audi 1.6l / 2.0l 4-cylinder TDI engines" Exhaust gas treatment module Versions To achieve the EU 6 emission limits, an NOx aftertreatment system will be integrated into the close-coupled exhaust gas treatment module from the EU 5 engine together with the oxidising catalytic converter and the coated particulate filter Depending on model version, a distinction will be made in future between two EU variants of the close-coupled exhaust gas treatment module: Achieving the EU 6 emission limits requires the use of a Selective Catalytic Reduction (SCR) system • System with NOx accumulator catalyst (NSK) for smaller and lighter vehicles based on the Modular Transverse Matrix (MQB) • System with Selective Catalytic Reduction (SCR) for vehicles based on the Modular Longitudinal Matrix (MLB) with a larger flywheel mass (EU 6 heavy duty) Overview Exhaust gas recirculation servomotor V339 EGR valve EGR cooler Exhaust gas treatment module Turbocharger 622_028 Exhaust gas treatment module with SCR system The substrate of the close-coupled exhaust gas treatment module is made of metal, enabling the module to reach its operating termperature more quickly This metal body is coated with a substrate of metal oxides, e.g aluminium oxide, with additional layers of platinum and palladium These precious metals act as catalysts for hydrocarbons and carbon monoxide Integrating the SCR coating into the particulate filter using copper zeolite enables the system to be positioned close to the engine After cold-starting the engine, the operating temperature of the SCR catalyst is reached more quickly and maintained for longer during low-load vehicle operation Additional engine modifications are required for heating the catalytic converter The reducing agent injector N474 is integrated directly downstream of the oxidising catalytic converter and above the transition funnel, with the result that the entire volume in the funnel is available for carburetion Since air cooling is no longer sufficient due to the high thermal load, the reducing agent injector has a coolant jacket which, in addition to the valve, protects the electrical connection against overheating The reducing agent injector is integrated in the low-temperature circuit of the engine cooling system, see page 34 Design Exhaust gas temperature sender G448 Reducing agent injector N474 (water cooled) Exhaust gas temperature sender G495 Oxygen sensor G39 NOx sender G295 Turbocharger Mixer Oxidising catalytic converter Exhaust gas temperature sender G235 Differential pressure sender G505 Connection for exhaust gas pressure sensor G450 SCR-coated diesel particulate filter 622_022 10 Reducing agent active tank on Audi A8 ’14 To extend the range of the SCR system, a quasi-reserve tank is installed in the spare wheel well in addition to the active tank In this case, the passive tank has been adapted to fit the spare wheel well and total reducing agent capacity has been increased by 12 litres The passive tank does not have any built-in sensors or a reducing agent heater Reducing agent delivery is dependent on the fill level in the active tank and carried out by a transfer pump on the active tank The passive tank is not filled via the reducing agent filler neck like the active tank It has to be filled separately The passive tank can be filled during the service event using filling unit VAS 6542 or the filler bottle (Kruse bottle) Overview Transfer line from active tank Bleeding line to reducing agent active tank Connector in bleeding line Reducing agent transfer pump V436 Pasisve tank filler neck (not colour coded) 622_027 26 Swirlpot in active tank The swirlpot is installed in the reducing agent active tank from below and houses the following components: • Reducing agent pump V437 • Reducing agent pressure sender G686 • Reducing agent tank heater with heating mat Z102 • Reducing agent filter • Reducing agent tank sender G684 • Reducing agent temperature sender G685 Pumping operation Reducing agent heater The reducing agent pump (SCR metering pump) is configured as a brushless or electrically commutated three-phase motor It pumps the reducing agent to the reducing agent injector N474 via an SCR pressure sensor The pressure sender for the reducing agent metering system G686 measures the outlet pressure of the metering pump to the reducing agent injector within a pressure range from -0.5 bar to approx 9.0 bar (relative) The reducing agent temperature sender G685 measures the reducing agent temperature within a range from -40 °C to 80 °C As the reducing agent freezes at -11 °C, the reducing agent metering system is equipped with a heater The swirlpot has an integrated heating mat which heats the swirlpot together with all its internal components (resistance heater) The metering line to the external reducing agent injector N474 is heated by a resistance heater Overview Reducing agent pump V437 Reducing agent tank heater Z102 Thermo mat strips Reducing agent tank sender G684 Reducing agent temperature sender G685 622_015 27 Sensors and actuators System overview (shown using the 3.0l V6 TDI engine as an example) Sensors Air mass meter G70 Engine speed sensor G28 Hall-effect sensor G40 Powertrain CAN databus Coolant temperature sensor G62 Radiator outlet coolant temperature sensor G83 Temperature sender for engine temperature control G694 Fuel temperature sender G81 Oil pressure switches 1 + 2 F445, F446 Fuel pressure sensor G247 Accelerator pedal position sensor G79 Accelerator pedal position sensor G185 Exhaust gas recirculation potentiometer G212 Brake light switch F NOx sender G687 Private bus Brake servo pressure sensor G294 Charge pressure sensor G31 Intake air temperature sensor G42 Oxygen sensor G39 Reducing agent tank sender G684 Reducing agent pressure sender G686 Reducing agent temperature sender G685 Exhaust gas temperature sender G495 Engine management control unit J623 EGR temperature sensor G98 Exhaust gas temperature sender G235 Exhaust gas temperature sender (downstream of diesel particulate filter) G648 Exhaust gas temperature sender (BIN 5 only upstream of cat) G448 Differential pressure sender G505 Auxiliary signals: – Cruise control system – Speed signal – Start request to engine control unit (Kessy + 2) − Terminal 50 – Crash signal from airbag control unit 28 Diagnostic port Actuators Injectors, cylinders – N30, N31, N32 Injectors, cylinders – N33, N83, N84 Automatic glow period control unit for J179 Glow plugs 1 – 3 Q10, Q11, Q12 Glow plugs 4 – 6 Q13, Q14, Q15 Oil pressure regulating valve N428 Throttle valve control unit J338 Fuel metering valve N290 Fuel pressure regulating valve N276 Thermostat for mapped engine cooling F265 Exhaust gas recirculation servomotor V338 Cylinder head coolant valve N489 Exhaust gas recirculation cooler change-over valve N345 Exhaust turbocharger control unit J724 Intake manifold flap motors and V157, V275 Control unit for catalytic converter heater J10211) Catalytic converter heater Z1191) Auxiliary signals: – Air-conditioning compressor – Auxiliary coolant heater – Fan settings + – Auxiliary air heater element Z35 Electro/hydraulic engine mounting solenoid valve, left and right N144, N145 Reducing agent metering system control unit J880 Reducing agent injector N474 Reducing agent line heater Z104 Reducing agent pump V437 Reducing agent transfer pump V436 Reducing agent tank heater Z102 Oxygen sensor heater Z19 Fuel pump relay J17 Fuel predelivery pump G6 Auxiliary fuel pump relay J832 Auxiliary fuel pump V393 622_012 1) Installed in a limited number of models only 29 Reducing agent pump V437 The reducing agent pump V437 (metering pump) is housed inside the swirlpot Integrated in the swirlpot: reducing agent pump V437 A so-called "brushless motor" is used in the metering pump This type of electric motor is also known as an electrically commutated three-phase motor The brush assembly of copper plates and carbon brushes has been replaced by intelligent electronics 622_059 Function The engine control unit activates the SCR metering pump electronics by sending CAN signals to the SCR control unit, which in turn activates the components by means of analogue signals To make the rotor rotate, a three-phase AC field must be generated This means that the brushless motor actually acts as a three-phase AC motor, and the three-phase AC field is generated artificially The stator coils are activated in such a way that a rotating magnetic field is generated in the stator coils The rotor is forced by the permanent magnet pairs to continuously realign itself and thereby follow the magnetic field lines This causes the rotor to rotate Functional principle Coil winding circuits Stator The position of the rotor is detected by the reducing agent metering system control unit J880 via the de-energised coil pair This feedback signal is also known as a "back EMF" signal (EMF = ElectroMotive Force) Rotor Output stage Electronic control unit 622_061 Back EMF signal Permanent magnet Coil 622_060 30 Reducing agent tank sender G684 (level sender) All switches open (full) Switches and No restart The upward movement of the float is limited by a retaining disc When the reducing agent expands in frosty conditions, the retaining disc gives the float enough freedom of movement to allow for expansion Fill level characteristic Resistance The second-generation SCR level sender differentiates between seven individual reducing agent levels ranging from "empty" to "full" The downward movement of the float is limited by the design of the level filter housing Switch Switch Switch Switch 2, reserve Switch 1, "empty" AdBlue® level Installation location and design Float with magnets 622_051 Retaining disc Reducing agent tank sender G684 622_016 Refilling Depending on model and tank system, between three and four 0.5 gal Kruse bottles (5.7 l – 7.6 l) are needed to refill the tank and thereby reset the sensors The relevant information is displayed on the adhesive label in the fuel filler flap One gallon (gal) is the equivalent of about 3.8 litres Adhesive label for European spec models (example) Adhesive label for US spec models (example) 622_062 622_052 31 Particulate sensor G784 with control unit (to be introduced at a later date) The particulate sensor is integrated in the exhaust downstream of the particulate filter and allows for diagnosis of the particulate filter Method of operation The sensor element works on the resistance measurement principle Deposited soot particles form electrical pathways between the electrode chambers, to which an electrical current flows The sensor element is regenerated by regular heating The diagnostic software responsible for the diesel particulate filter assesses the performance of the diesel particulate filter based on the measured electrical current 622_045 Reducing agent injector N474 (metering valve) The metering system reducing agent (AdBlue®) in an exhaust system includes a control valve, a metering valve and a cooling unit The cooling unit configured as a cooling jacket It is integrated in the engine coolant circulation system and provides for effective cooling of the metering valve Electrical connection Connection for AdBlue® line Coolant flows through the injector along coolant ducts With this so-called counterflow cooling system, the cooled coolant enters the injector at the bottom and flows through the injector before being released back into the cooling system at the top of the injector Coolant outlet Coolant inlet AdBlue® outlet 622_038 32 Connection to the cooling system of the 3.0l V6 TDI engine on the Audi A8 ’14 Reducing agent injector N474 10 11 14 13 15 12 16 17 622_029 Key: Front heater heat exchanger Rear heater heat exchanger Coolant circulation pump V50 Transmission oil cooler (ATF heat exchanger) Gearbox coolant valve N488 Injector for reducing agent N474 Non-return valve Coolant expansion tank Coolant temperature sender G62 Cooled coolant 10 11 12 13 14 15 16 17 Heated coolant EGR cooler Coolant shutoff valve Alternator Engine oil cooler Oil temperature sender G8 Temperature sender for engine temperature regulation G694 Coolant thermostat Coolant pump ATF 33 Connection to the cooling system of the 2.0l V6 TDI engine on the Audi A8 ’14 Reducing agent injector N474 10 12 13 11 622_030 Key: Coolant temperature sender G62 Coolant thermostat Charge air cooling pump V188 Injector for reducing agent N474 Intercooler integrated in intake manifold Intercooler coolant radiator Coolant pump Cooled coolant 34 10 11 12 13 Heated coolant Non-return valve Throttle valve Engine oil cooler Radiator Radiator fan V7 Radiator fan V177 ATF Display strategy Overview Depending on the fill level of the reducing agent tank, various messages are displayed in the instrument cluster, some requiring the assistance of a special workshop or that the reducing agent tank be refilled with AdBlue® Faults in the SCR system are also indicated by corresponding messages The various messages are summarised in the table below The style of display can vary depending on model and instrument cluster version SCR warning strategy, text messages and audible signals Remaining range Display from 2400 km or 1500 miles Warnings given via the display in the instrument cluster are also indicated by a gong tone The remaining range is decremented in increments of 100 km or 100 miles A warning is given via the display at intervals of 400 km or 400 miles, or every 8 hours from 1,100 km or 700 miles The remaining range is decremented in increments of 50 km or 50 miles A warning is given via the display at intervals of 100 km or 100 miles, or every 8 hours from 1,000 km or 600 miles The remaining range is displayed together with a buzzer tone and a warning that it will not be possible to restart the engine when the remaining range expires The remaining range is decremented in increments of 50 km or 50 miles A warning is given via the display at intervals of 100 km or 100 miles, or every 4 hours from 200 km or 100 miles Once the reducing agent range decreases to less than 200 km or 100 miles, the remaining range is decremented in increments of 10 km or miles A warning is given via the display at intervals of 20 km or 10 miles, or every 8 hours at 0 km or 0 miles A warning that it will not be possible to restart the engine is given via the display in the instrument cluster and a buzzer tone sounds three times Colour 35 Messages relating to reducing agent fill level The displayed remaining range is calculated based on the residual amount of reducing agent in the tank and the rate of reducing agent consumption When the reducing agent range drops to 2400 km or less, a warning is sent to the instrument cluster The warning is repeated on the basis of elapsed time or distance Fill level, stage This driver warning appears if the AdBlue® level is sufficient only for the remaining range indicated via the driver information system AdBlue® must be added The displayed remaining range is calculated based on the residual amount of reducing agent in the tank and the rate of reducing agent consumption, starting at 2400 km Refill AdBlue Range 2,400 km See owner's manual The remaining range is displayed in increments of 100 km 622_055 Fill level, stage This driver warning appears if the AdBlue® level is sufficient only for the remaining range indicated via the driver information system AdBlue® must be added Otherwise, you will not be able to restart the engine after the indicated range has expired The remaining range is displayed in increments of 50 km Refill AdBlue No restart in 1000 km See owner's manual 622_056 Fill level, stage This driver warning is displayed if the AdBlue® reducing agent tank is empty AdBlue® must be added Otherwise, the engine will not restart after turning off the ignition Refill AdBlue No restart See owner's manual 622_053 36 Fault warnings An SCR system fault immediately triggers the remaining range display, regardless of the actual tank fill level The SCR system fault is activated if one of the following event memory entries is indicated: The remaining range is decremented by the distance covered and is not dependent on reducing agent consumption • A fault in an SCR system component relevant to operation, e.g the delivery pump, the reducing agent injector, the pressure sensor, the pressure regulator, the SCR control unit or wiring and the CAN interface • A large difference between nominal and actual reducing agent consumption • Detection of a reducing agent misfill System malfunction If the AdBlue® tank has been filled with a fluid other than AdBlue® and a misfill is detected by the system or a system fault exists, a driver warning is displayed AdBlue: System malfunction 622_057 System fault with imminent restrictions on engine starting This driver warning is displayed if the vehicle has only the remaining range indicated in the driver information system Proceed to the nearest authorised Audi service centre and have the fault corrected Otherwise, you will not be able to restart the engine after the indicated range has expired After another 50 km have been covered, the yellow warning lamp comes on to indicate a system fault AdBlue: System malfunction No restart in 1000 km See owner's manual 622_058 System fault with restrictions on engine starting This driver warning is indicated if a misfill has been detected or if a system fault exists Proceed to the nearest authorised Audi service centre and have the fault corrected Otherwise, the engine will not restart after turning off the ignition AdBlue: System malfunction No restart See owner's manual 622_054 37 Service Tools VAS 6557 SCR vacuum box VAS 6532 SCR test box 622_036 622_037 Extracting AdBlue® from the SCR system Assessment of the SCR system in connection with "Guided Fault Finding" VAS 6542 AdBlue® filling unit VAS 6606 198-pin isolating box -1- and VAS 6606/10 Test adapter -21 2 622_035 Filling the reducing agent tank prior to pre-delivery vehicle inspection or during a relevant service event T40268 Wrench 622_039 Removing the swirlpot from the SCR tank 38 622_034 Diagnostics of control units with 198-pin terminals (UDS control units) Annex Self Study Programmes For further information about the technical features of Audi EU 6 diesel engines with SCR system, refer to the following Self Study Programmes SSP 428 Audi 3.0l V6 TDI engine with ultra low emission system (EU6, LEV II, BIN5) Order number: A08.5S00.56.20 • Information on the design and function of an SCR system How to handle AdBlueđ face to face with the customer and in the service workshop SSP 479 The Audi 3.0l V6 TDI engine (second generation) Order number: A10.5S00.72.20 Information on the 3.0l V6 TDI engine • Mechanicals • Oil supply • Air circulation and charging • Common rail injection system • Cooling system SSP 608 The Audi 1.6l and 2.0l 4-cylinder TDI engines Order number: A12.5S00.92.20 Information on the 2.0l R4 TDI engine • Mechanicals • Oil supply • Air circulation and charging • Common rail injection system • Cooling system SSP 625 Audi A3 saloon Order number: A13.5S01.09.20 Information on the 2.0l R4 TDI engine in the MQB • SCR tank with in-tank SCR dosing module • Exhaust system 39 All rights reserved Technical specifications are subject to change Copyright AUDI AG I/VK-35 service.training@audi.de AUDI AG D-85045 Ingolstadt Technical status 10/13 Printed in Germany A13.5S01.06.20 622 Audi Vorsprung durch Technik ... Selective Catalytic Reduction (SCR) system • System with NOx accumulator catalyst (NSK) for smaller and lighter vehicles based on the Modular Transverse Matrix (MQB) • System with Selective Catalytic. .. emission limits A modern "Selective Catalytic Reduction" (SCR) emission control system utilises the chemical synthesis product of urea (AdBlue®) to reduce NOx emissions In SCR systems, AdBlue® reacts... 10 Ammonia blocking catalytic converter An ammonia blocking catalytic converter with a combined SCR and oxidising catalyst coating is located downstream of the SCR- coated diesel particulate filter