485 Audi Vorsprung durch Technik Self Study Programme 485 Audi 1.2l TFSI engine 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 09/10 Printed in Germany A10.5S00.78.
Following on from the A3 with its 92 kW 1.4l TFSI engine which paved the way for small petrol engines with superior torque and high fuel economy by combining turbocharging with direct fuel injection, Audi presents the 1.2l TFSI - yet another engine with TFSI technology for the entry-level segment. Economy and pulling power are still the key success factors, especially in the light of the on-going heated debate on CO2 emissions.
Contents Introduction Specifications _________________________________________________________________________________________________________________________________________________ 5 Engine mechanicals Weight reduction measures _________________________________________________________________________________________________________________________________ 6 Cylinder block _ ____________________________________________________________________________________________________________________________________
Introduction Brief technical description • Newly developed aluminium cylinder block with innovative cast iron cylinder liners • Two-valve cylinder head with inclined overhead valves • Steel crankshaft with reduced conrod and main bearing diameters of 42 mm • Low-friction lightweight crank drive • Positive crankcase ventilation system with oil separator integrated in the cylinder block and cylinder head • Active coolant pump • Easy-to-service split lightweight timing case with plastic and magnesium a
Specifications Torque/power curves 1.2l TFSI engine CBZA Power in kW Torque in Nm 1.2l TFSI engine CBZB Power in kW Torque in Nm Engine speed [rpm] 485_019 Engine code CBZA CBZB Type 4-cylinder inline engine 4-cylinder inline engine Displacement in cm3 1197 1197 Stroke in mm 75.6 75.
Engine mechanicals 114 kg -24.5 kg The 1.2l TFSI engine was developed on the basis of the 1.4l TFSI engine (EA 111). Compared to the 1.4l engine, the 1.2l engine has been reduced in weight by 24.5 kg by adopting various measures (see illustration). 1.4l TFSI (92 kW) Engine parts/attachments -2.5 kg Two-piece timing case -2.
Cranktrain The following modifications have been made compared to the 1.
Chain drive The camshaft is driven by a maintenance-free chain mechanism. The chain is tensioned by a hydraulic chain tensioner. This presses the tensioning rail against the chain below the camshaft gear. The chain tensioner is bolted into the cylinder head from the outside (see Fig. 485_025). The sliding rail on the side opposite the tensioning rail prevents excessive oscillation of the chain.
Cylinder head The change from four valves per cylinder to two-valve technology has reduced friction and saves weight. This has made it necessary, however, to rearrange the injectors and the spark plugs. Based on its experience with the direct injection systems of the TSFI engine family, Audi has taken the specifications for this engine with respect to carburetion, charging motion and combustion rate and transferred them to a two-valve combustion process with non-variable valve timings*.
Components on the cylinder head 6 7 5 1 4 10 12 11 2 3 8 9 14 13 15 19 20 16 21 17 22 18 23 24 25 26 485_016 10
Legend: 1 High-pressure fuel pump 14 Ladder frame (camshaft bearing) 2 Fuel pressure regulating valve N276 15 Support element (intake) 3 Low pressure connection (supply) 16 Roller cam follower (intake) 4 High pressure connection 17 Valve spring (intake) 5 Suspension eye 18 Intake valve 6 Hall sender G40 19 Injectors N30 – N33 7 Cylinder flange screws 20 Roller cam follower (exhaust) 8 Sealing cover 21 Valve spring plate (exhaust) 9 Camshaft 22 Valve steam
Intake valves The intake valve seats have a special shape (valve masking). This ensures that the air can only flow in a certain area inside the cylinders during short valve strokes. In the process, the air is directed towards the cylinder wall, resulting in more intensive swirl and a higher flow rate. This promotes formation of a homogeneous air-fuel mixture inside the combustion chamber.
Positive crankcase ventilation Unlike with the 1.4l 92 kW TFSI engine, an internally controlled positive crankcase ventilation system is employed. A plastic oil separator is bolted to the cylinder block. The oil is separated off from the blow-by gases* in the oil separator and drips into an oil collecting chamber. An oil drain valve prevents the oil from running into the oil pan. This valve is kept closed by the pressure present inside the crankcase.
System overview This schematic diagram includes the crankcase ventilation systems, the vacuum supply and the tank ventilation system. The schematic diagram shows by way of example the system of a vehicle driven by a seven-speed dual clutch gearbox 0AM (S tronic) with a suction jet pump.
Vacuum supply The lack of brake boost due to the vacuum being too low is compensated by the ESP hydraulics through active brake pressure build-up. The necessitates gauging the pneumatic pressure in the brake servo. The difference between the pneumatic pressure and the ambient pressure is a direct measure for the maximum achievable brake boost. A pressure difference of zero means that the brake servo has reached its saturation point*.
Oil supply Oil circuit Oil pump The smaller main and conrod bearing dimensions and the twovalve drive train with only a single camshaft significantly reduce engine oil requirements. The Duocentric oil pump is mounted at the bottom of the cylinder block and driven by the crankshaft via a maintenance-free toothed chain drive. This allows a smaller oil pump to be installed and the average work output to be reduced by approx. 50 % compared to the closed-loop pump.
Oil filter As with the 1.4l TFSI engine, a filter module with oil filter cartridge is employed in the 1.2l TFSI engine. The oil filter cartridge is accessible from above to allow easy servicing. To ensure that no oil runs down the engine when replacing the oil filter, a return channel in the timing case cover opens when the filter cartridge is released. This allows the oil to flow directly into the oil pan. This channel is sealed by a spring-loaded seal when fastened.
Air supply Intake manifold volume has been kept to a minimum for rapid exhaust turbocharger response. Charge pressure is controlled by the charge pressure actuator V465. The rapid response of the electrical charge pressure actuator ensures that the wastegate opens quickly in overrun mode, thereby reducing the pumping effort of the turbocharger.
Charge pressure actuator V465 with charge pressure actuator position sensor G581 Charge pressure actuator V465 with charge pressure actuator position sensor G581 The charge pressure actuator is an integral part of the exhaust turbocharger. Its purpose is to regulate the charge pressure.
Charge pressure control function The charge pressure control determines the air mass which is compressed by the exhaust turbocharger and pumped into the cylinders. Exact charge pressure control is provided by two pressure sensors each fitted with an intake air temperature sender. Wastegate closed The wastegate* remains closed until the nominal charge pressure is reached.
Calculating the charge pressure The charge pressure is calculated in the engine control unit using the signals from: • charge pressure sender G31 with intake air temperature sender 2 G299 • intake manifold pressure sender G71 with intake air temperature sender G42 The signal from the ambient pressure sender in the engine control unit is used as a correction variable.
Cooling system Overview The 1.2l TFSI engine has two independent cooling systems which are connected and disconnected by nonreturn valves and a flow restrictor: • the charge air cooling system • the engine cooling system which, in turn, is subdivided into two circuits. Due to the presence of the flow restrictor and nonreturn valves, it is necessary to vent the entire system using VAS 6096 or using the "test program" on a vehicle diagnostic tester after carrying out work on the cooling system.
Engine cooling system The separate coolant flows inside the cylinder head and inside the engine block allow different temperatures to be achieved in both of these components by using a thermostatic housing with dual thermostats. The cylinder head thermostat begins to open when the coolant temperature reaches approx. 80 °C. It achieves its maximum opening cross-section at a temperature of 135 °C. On the other hand, the thermostat for the cylinder block begins to open at 87 °C.
Engine cold After cold-starting the engine, the active coolant pump is activated, thus stopping the coolant flow. The coolant flows through the coolant pump, the cylinder block and the heater heat exchanger, and then back to the coolant pump. Parallel to this, the coolant flows through the oil cooler. If no heating is requested, the engine heats up very quickly. If heating is requested, coolant circulation is stopped for approx. two minutes. Both thermostats are closed.
Engine warm, a thermostat opens If the coolant has reached a temperature of 80 °C, the cylinder head thermostat opens. The main radiator is now integrated in the coolant flow.
Engine warm, both thermostats open When the coolant in the cylinder block reaches a temperature of 87 °C, the thermostat for this circuit opens with the result that the cylinder is now incorporated into the coolant circulation system.
Thermal management The task of the thermal management system is to enable the engine to attain its operating temperature quickly since this improves fuel economy and reduces exhaust emissions. Thermal management is implemented by stopping the circulation of coolant during the warm-up phase: • up to a coolant temperature of 90 °C at "heater off" • up to 2 minutes at "heater on" This is implemented technically by using an active coolant pump.
Function Basically, the active coolant pump works in much the same way as a conventionally driven coolant pump, i.e. with permanent mechanical drive. No coolant flow The coolant flow is interrupted by sliding an orifice plate over the pump vane. The orifice plate is actuated by vacuum and spring pressure. When the adjustment mechanism is activated (vacuum), the orifice plate counteracts the spring pressure and covers the pump vane. Coolant circulation is now interrupted.
Fuel system System overview High-pressure fuel pump High pressure fuel rail Fuel pressure sender G247 Injectors 1 – 4 N30 – N33 To engine control unit Fuel pressure regulating valve N276 Fuel filter Battery (positive) 485_003 Fuel pump control unit J538 Fuel predelivery pump G6 Injectors N30 – N33 The configuration of the injectors, and in particular the orientation of the six individual jets, has been adapted to the engine.
Engine management Overview of the Simos 10 system on the Audi A3 Sensors Charge pressure sender G31 Intake air temperature sender 2 G299 Intake manifold pressure sender G71 intake air temperature sender G42 Engine speed sender G28 Hall sender G40 Throttle valve control unit J338 Throttle valve drive angle sender with electronic power control G187, G188 Charge pressure actuator position sensor G581 Clutch position sensor G476 Powertrain CAN databus Accelerator pedal position sensor G79 Accelerator pe
Actuators Fuel pump control unit J538 Fuel predelivery pump G6 Injectors for cylinders 1 – 4 N30 – N33 Ignition transformer N152 Engine control unit J623 with ambient pressure sender Throttle valve control unit J338 Throttle valve drive for electronic power control G186 Motronic power supply relay J271 Fuel pressure regulating valve N276 Charge pressure actuator V465 Coolant circuit solenoid valve N492 Additional coolant pump relay J496 Coolant circulation pump V50 Control unit in dash panel insert J
Engine control unit J623 The engine control unit J623 uses the Simos 10 system. It supports the UDS (UDS = universal diagnostic component) diagnostic data protocol. The ambient pressure sensor is also integrated in the engine control unit. All components can be tested electrically using the V.A.G 1598/39 adaptor cable and the V.A.G 1598/42 test box.
Ignition system The ignition system is simple in design and has a very favourable cost-benefit ratio. It is already used on a number of models within the VW Group. It is a mapped ignition system with static high-voltage distribution and cylinder-selective adaptive knock control. The engine control unit monitors the ignition process and sends a signal to the power output modules. These modules open and close the primary current of both ignition coils.
Ignition transformer N152 The ignition transformer for static voltage distribution is bolted on the intake manifold. Its task is to simultaneously ignite the air-fuel mixture via the spark plugs. The ignition angle is set individually for each cylinder. Effect of failure If the ignition transformer fails, the engine will be shut down. There is no substitute function for the ignition transformer. A diagnostic trouble code is stored in the ECU fault memory and the exhaust warning lamp K83 is activated.
Service Special tools Counter-hold tool 3415 with adaptor 3415/2 Torque wrench VAS 6583 485_048 485_049 The counter-hold tool and the adaptor can be used to hold the belt pulley securely in place and to slacken or tighten the belt pulley fastening screw. The electronic torque wrench can be used, for example, for tightening the screws of the lower and upper timing cases.
Scope of maintenance Maintenance work Interval Engine oil change interval with LongLife oil up to 30,000 km or 24 months depending on SID1) (change interval is dependent on driving style) Engine oil to VW standard 50400 Engine oil change interval without LongLife oil Fixed interval of 15,000 km or 12 months (depending on which occurs first) Engine oil to VW standard 50400 or 50200 Engine oil filter change interval during every oil change Engine oil change quantity (for customer service) 3.
Annex Glossary All terms shown in italics or by an asterisk (*) in this Self-Study Programme are explained here. Blow-by gases These are also referred to as leakage gases. When the engine is running, the blow-by gases flow from the combustion chamber and into the crankcase, bypassing the piston. They are produced by the high pressures which occur in the combustion chamber and constitute absolutely normal leakage around the piston rings.
Test your knowledge 1. Which of the following statements regarding the mechanical coolant pump is correct? □ □ □ a) The mechanical coolant pump has been deleted. The electrical coolant circulation pump V50 performs the task of the mechanical coolant pump. b) The mechanical coolant pump is shut down when the engine is cold-started, thus allowing the engine to heat up more quickly.
Summary With the 1.2l TFSI engine, Audi offers an engine developed within the Volkswagen Group in the 100 kW class. It is a small and, therefore, economical unit. Nevertheless, it is a performance engine and, above all, it meets the required emission standards. All development objectives were achieved: • • • • The engine was first employed on the VW Golf and subsequently on all A0 and A class Group models. Compared to the competition, the 1.2l TFSI engine is one of the front runners.
485 Audi Vorsprung durch Technik Self Study Programme 485 Audi 1.2l TFSI engine 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 09/10 Printed in Germany A10.5S00.78.
