Engine – Design

Design and Function

Applies to: 2007–2011; B8444S

Engine block

The cylinder heads and valve covers are made of aluminum.

The seal between the cylinder head and cylinder block occurs using two cylinder head gaskets, one for each cylinder head. The cylinder head gasket is made up of three layers of stainless steel. Two outer and a center which act as a seal around the cylinders. The outer surfaces of the gasket are covered by a rubber layer which functions as a seal. The seal between the other planes is made using liquid gasket.

The engine has two cylinder banks. The left cylinder bank is slightly offset compared to the right. This allows the use of the vehicle's existing member system and crumple zones.

The engine has double pairs of overhead camshafts - one intake camshaft and one exhaust camshaft in each cylinder head. The camshafts are chain-driven.

The cylinders are numbered in the order in which they are installed on the crankshaft when seen from the front (from the camshaft's timing gear).

The engine has four valves per cylinder. The valves are angled at 19 degrees. The valve diameter of the intake valves is 35 mm and the exhaust valve's is 30 mm. The valves are stellite coated. The valve stem diameter for both inlet and exhaust is 5.5 mm.

The combustion chamber is the "Pent roof" type. Together with the V arranged valves this gives optimal and fast filling and direct flushing via the intake channel followed by the combustion chamber (cross-flow) and exhaust channel.

The squish surfaces together with the centrally positioned spark plug provide optimal combustion of the air/fuel mixture, low knock sensitivity and low, stable exhaust emissions.

Cylinder head

The engine's two cylinder heads are in principle mirror images of each other. The cast oil galleries in the cylinder head ensures good oil supply to the camshafts and the mechanical valve lifters.

Cylinder block

The cylinder block is made of cast aluminum. It has a stiff rib structure for better rigidity and thereby better sound and vibration properties.

The cylinder block has eight cast-iron cylinder liners molded into the cylinder block. They cannot be replaced.

The coolant jacket goes halfway down the cylinders to ensure quicker heating and thereby reduce hydrocarbon emissions. Certain sections of the coolant jacket are deeper to reduce the risk of the cylinder deformation.

Intermediate section

The intermediate section is made of aluminum. The crankshaft bearing caps are integrated in the intermediate section. The bearing caps are made of cast iron. The caps are fixed with four screws per cap.

Oil sump

The oil pan is made of pressed aluminum. It has baffles to prevent the oil moving too much. Because of the exterior dimensions of the engine, the oil pan has a unique shape in order to hold the necessary oil volume. The oil pan is made in two parts for manufacturing reasons.

An electric oil level sensor is located in the pan. There is also a normal oil dipstick for manual checks of the oil volume.

Pistons and connecting rods

The pistons are cast and are made of a light metal alloy. The piston mantle is coated with graphite. The first groove is hard anodized to minimize wear.

The piston is equipped with two compression rings and a three piece oil ring.

The connecting rods are forged. The contact surface between the bearing cap and the connecting rod is treated. Guide pins contribute to good alignment. The connecting rod bearings are aluminum bearings. The bearings are lead free.

The piston transfers the compressive force of the ignited fuel/air mixture to the crankshaft via the connecting rod. The piston rings form a seal so that the fuel/air mixture does not force its way down past the piston. The top ring ensures a seal between the piston and the cylinder. The second ring also seals and scrapes away any oil during the downward movement of the piston. The third ring makes sure the oil drains via the drain hole.

The pistons are oil-cooled. This is necessitated by the short distance between the piston head and the top piston ring.

Crankshaft and balancer shaft

1. Balancer shaft
2. Crankshaft

The crankshaft is made of carbon steel with a nitride hardened surface. The crankshaft bearings have separate caps, the intermediate section of the cylinder block makes up the lower half of the bearing. The crankshaft has five main bearings where the third also acts as an axial bearing. The main bearings are aluminum bearings.

The crankshaft has offset pins. Two connecting rods are mounted on each crankshaft pin with an internal offset of 30°.

Big-end bearings and axial bearings are lead-free.

Two splined joints are located at the front end of the crankshaft, the inner one drives the oil pump. The timing chain gear is located on the outer joint.

S80

The crankshaft has a two part vibration damper consisting of a hub and an active mass. The crankshaft vibration damper drives the auxiliary belt.

XC90

The crankshaft has a three part vibration damper consisting of a hub and two active masses. The hub is located between the inner and outer masses. The crankshaft vibration damper drives the auxiliary belt.

The 60 degree angle between the two cylinder banks means that the engine is equipped with a balancer shaft. This is to give the vibration characteristic which corresponds to a 90 degree V8. The balancer shaft is located in the center of the engine, above the crankshaft. The balancer shaft rotates in the opposite direction to the crankshaft. It is driven by the crankshaft using the same chain that drives the intake camshafts. The balancer shaft rotates at the same speed as the crankshaft.

The balancer shaft is made of spherolitic cast iron (nodular iron).

Camshafts and valve system

The engine has double pairs of overhead camshafts, one intake camshaft and one exhaust camshaft in each cylinder bank. The intake camshafts are located in the middle of the engine while the exhaust camshafts are placed on the outside.

The camshafts are made of cast iron. They are hollow to keep the weight down. Each camshaft pair is mounted in its respective cylinder head with five loose bearing caps per camshaft.

The camshafts work directly on the valve stem via the valve lifters. There is a certain amount of play (valve play) between the valve depressors and the cam lobes. Valve play is adjusted to make up for the longitudinal differences between the valve and cylinder head that occur upon warm-up. The valve depressors are solid and made of steel.

Each camshaft has a CVVT unit. The reset angle is 40.5 crankshaft degrees for the intake camshafts and 42.5 crankshaft degrees for exhaust camshafts.

• Intake camshafts open -8° to 32,5° before top dead center (BTDC) and close 60° to 19.5° after the bottom dead center.
• Exhaust camshafts open 62° to 19.5° before bottom dead center and close -10° to 32.5° after the top dead center (TDC).

Camshaft chain drive

The crankshaft drives the intake camshafts and the balancer shaft using a camshaft chain (1). The camshaft is tensioned by a hydraulic chain tensioner. The tensioner is supplied with oil from the normal lubrication system. The camshaft chain is lubricated with oil via a separate nozzle (2).

The intake camshafts in turn drive the respective exhaust camshafts via their chain (3). This intermediate drive means that the outer exhaust camshafts can have smaller pulley wheels which reduces the size of the engine. The intermediate drive chains each have their own hydraulic tensioner. The tensioner is supplied with oil from the normal lubrication system.

A cover seals the area for the camshaft chain drive.

The system requires no maintenance during the entire life of the engine. Both the chain guide and the chain tensioner have plastic inserts on the treads for quiet operation.

Lubrication system

The lubrication system has a large supply line with a strainer which prevents large contaminants from reaching the oil pump.

The oil pump (1) is driven by the crankshaft. The oil pump is a rotor pump with integrated pressure control valve. The valve opens at approximately 5.0 bar and prevents excessively high pressure which could damage the oil cooler.

The oil cooler is a flat oil cooler. The space for oil and coolant is divided alternately between the plates.

The oil filter (2) is a loose filter element placed in a housing. The overflow valve for a blocked filter is in the cover.

Fuel system

A specially designed fuel system is used to reduce the height of the engine.

The fuel system is made of stainless steel to ensure reliability. The fuel hose is made of nylon to reduce the weight of the engine.

Intake system

An induction system with two modes is used to increase torque at low engine speed. Both the intake manifold and the equalizer tank are made of aluminum.

A moveable damper is located in the common area of the intake pipe. The damper separates the area lengthways into two chambers. The damper is controlled from completely closed to completely open, with no intermediate position. Up to an engine speed of 3200 rpm the damper is closed and the damper is open at higher engine speeds.

By dividing the area into two separate chambers, the area functions as two secondary intake pipes. The primary pipes are the cast pipes which lead to the inlet valves of the respective cylinder's intake valves from the collection volume. A closed damper provides secondary pipes while an open damper gives short secondary pipes.

Engine speeds up to 3200 rpm

The combined length and volume of the pipes is tuned to the piston movement and the valve opening times. The result is that the air pulses in time with the valve opening times. this means that the air is pumped into the cylinders when the inlet valves are open. The system gives a high a volumetric efficiency, that is, fills the cylinders and therefore produces a high torque.

In order not to disturb the pulse frequency the left chamber supplies 1, 4, 6 and 7 while the right chamber supplies cylinders 8, 3, 5 and 2, this is to interact with the firing order 1-8-4-3-6-5-7-2.

Engine speed (RPM) greater than 3200 rpm

At engine speeds greater than 3200 rpm the throttle opens. At these speeds the character of the pulses change character at the same time as a greater volume is required to supply the cylinders with air. The whole area/volume now supplies all cylinders. The common volume and the shape of the pipes is designed to exploit the pulses which occur in this engine speed (rpm) range.

If the damper does not open at 3200 rpm there is marked deterioration in performance from 3200 rpm up to 5000 rpm.

Throttle body

The throttle body is made of cast aluminum. The position sensor, which is located under the plastic cover, reads the position of the throttle disc and two engine connections that turn the throttle disc. The throttle disc position is determined by how much the driver depresses the accelerator pedal. The throttle body is warmed via engine coolant.

Cooling system

1. Cylinder block
2. Right cylinder head
3. Electric coolant pump
4. Heat exchanger (passenger compartment)
5. Preheating crankcase ventilation
6. Throttle body
7. Upper cooling hose
8. Bypass pipe
9. To cylinder head
10. Radiator
11. Oil cooler
12. Lower cooling hose
13. Thermostat housing
14. Coolant pump
15. Left cylinder head
16. Expansion tank with level sensor
17. Air bleed circuit

The engine is cooled used reversed cooling, that is, the cylinder head is cooled first. The system gives fast heating and contributes to reducing emissions.

The radiator is made of aluminum to withstand thermal fatigue as the radiator is alternately cooled with cold air and heated with hot coolant. The cooling system is regulated by a mechanical thermostat, which is located in the thermostat housing. The thermostat housing, in turn, is located on the inlet side of the coolant pump, between the radiator and the coolant pump.

The heart of the thermostat is a wax body which expands when energy, in the form of heat, is applied. A jiggle pin is located in the thermostat. Any air in the cooling system can be evacuated from the system using the jiggle pin.

Cold air is sucked through the cooler using an electric engine cooling fan installed on the fan shroud behind the radiator. The engine cooling fan is brushless and has six fixed stages. It is controlled by the engine control module (ECM).

Oil cooler

The oil cooler is round and has an inlet and outlet for oil as well as for coolant. The oil cooler is structured in layers, with alternating layers of coolant and oil flow. Because the oil cooler has very small slits, there is a large pressure drop here.

Auxiliaries belt

1. Generator (GEN)
2. Belt tensioner
3. Servo pump
4. Water pump
5. air conditioning (A/C) compressor.

All auxiliary units, the alternator, servo pump and A/C compressor are directly mounted in the engine block. They are driven by the vibration damper via an auxiliaries belt. This solution gives a compact design.

The coolant pump is also driven by the auxiliaries belt.

The auxiliaries belt has a mechanical belt tensioner.

Exhaust system

The exhaust system is made of double-layer sheeting to keep the temperature down. The inner sheet is 1.0 mm thick while the outer is 1.5 mm thick. There is 4-8 mm of space between the sheets.

An exhaust system extends from each cylinder bank. Each side consists of a manifold with close-coupled catalytic converter, pipes, bellows and a rear catalytic converter. Both sides join to form a common pipe after the rear catalytic converter.

The pipes are designed in such a way that the gas flow from the cylinders is not disruptive and there is good flow distribution to the catalytic converters. Bellows in front of the two rear catalytic converters absorb engine movements and compensate for manufacturing and assembly tolerances.

A catalytic converter consists of perforated stones of ceramic or metal (known as substrate). These are coated with a surface enlarger (washcoat) on which the precious metals platinum, palladium and rhodium, the catalysts, are applied.

The catalytic converter has an extra heat shield toward the radiator fan to reduce the temperature.

Four oxygen sensors are used to regulate the engine and monitor the catalytic converter. There is an oxygen sensor upstream and downstream of each close-coupled catalytic converter.

The two banks are almost exactly the same length to ensure good sound. The exhaust system provides the engine's characteristic V8 sound.

Applies to: 2007–2012; B5254T10, B5254T6

Engine

The entire engine is made of aluminum.

The engine has a compact "pent-roof" designed combustion chamber and V-arranged valves. This gives optimal and fast filling and direct flushing via the inlet manifold followed by the combustion chamber (cross-flow) and the exhaust channel.

The squish surfaces together with the centrally positioned spark plug provide optimal combustion of the air/fuel mixture, low knock sensitivity and low, stable exhaust emissions.

The engine's oscillation-mounting consists of an engine bracket bolted in the cylinder head. The engine bracket meets a bracket which is secured in the side member. The other attaching point is located between the transmission and body. A third attaching point for absorbing reaction forces and rotational forces in the bearing bracket for the drive shaft.

The cylinder head is "chill" cast, a slightly slower procedure than die-casting. This is so to integrate exhaust, inlet channel, water and oil casing in the design.

The engine is approved according to emission requirements Euro 5. All bearings are lead-free. Screws are Crome 6+ -free.

The bio-ethanol engine is a flexifuel engine. The engine has a new cylinder head with valve seats on the inlet side and new fuel distribution pipe compared to the gasoline engine. These parts have harder surface coating to maintain service life as bio-ethanol (E85) has a corroding effect.

Valve play is slightly less and the fuel injection supply manifolds have more capacity than on a petrol engine. The bioethanol engine has closer service intervals than a petrol engine

The petrol engine is powered by RON 95 fuel. The bioethanol engine is a flexifuel engine and is powered by bioethanol (E85) or RON 95 fuel and all possible mixtures of these two fuels.

The bioethanol engine has a pre-mounted engine block heater that should be used to facilitate starts at low temperatures, In addition, the amount of gasoline in the fuel mixture should increase at temperatures lower than -10°C, to facilitate cold starts. Because bioethanol has a lower energy content than gasoline the engine uses up 40 % more bioethanol compared with gasoline.

Engine block

1. Cylinder head cover
2. Cylinder head
3. Cylinder block
4. Intermediate section
5. Oil pan

The engine block is divided into five parts, where the cylinder head consists of two parts (1 and 2) and the engine block of three parts (3, 4 and 5). The seal between the cylinder head and engine block is a conventional cylinder head gasket, while sealing between the other gasket surfaces is done with liquid gasket.

Cylinder head, camshaft bearing housing

The two camshafts are carried in six bearing races each directly in the cylinder head's two halves. The upper half functions as a combined valve cover and camshaft cap. It has cast oil distribution pipes on the underside which ensures good oil supply to the camshafts and the mechanical valve depressors. The lower half has the maintenance-free mechanical valve depressors, valve springs and valves.

Cylinder block

The engine block is divided into three sections, the cylinder block, intermediate section and oil pan. The mating flange between the cylinder block and intermediate section is in the center line of the crankshaft.

The cylinder block has five cast iron cylinder sleeves cast into the cylinder block which cannot be replaced. The six main bearing seats have cast iron reinforcements in the intermediate section.

On the top of the intermediate section there are cast oil channels which distribute the oil to the main bearings and on via the crankshaft to the big ends.

The oil pan contributes to the rigid construction and acts as additional reinforcement. There is central smooth-bore oil duct for piston cooling.

Oil pan

The oil sump is made of die-cast aluminum with baffles. This is so that the oil will not move too heavily. It is secured in the cylinder block and in between there is a liquid gasket LOCTITE, which ensures sealing between the cylinder block and oil sump. The oil suction line running from the sump is made of plastic. The oil sump is provided with an oil level sensor.

Crankshaft

The crankshaft has six main bearings. The 5th main bearing is a throw-out bearing. At the front end of the crankshaft are two spline joints, the inner of which drives the oil pump. The drive gear for the timing belt and vibration damper is on the outer joint.

Blind splines gives the right position and guides the drive gear. The connecting rods are forged and the cracked joint between the connecting rod and cap provides exact fixation of the caps. The forged crankshafts give maximal strength at the same time as they contribute to a low sound level.

Piston

The piston has a uniform aluminum alloy with graphite coating on the sides. This coating gives a certain friction reduction as well as noise damping. The piston rings are of different material depending on where they are mounted on the piston. The upper compression ring is a nitride steel ring. The lower compression ring is made of cast iron and the oil scraper ring is a design consisting of three parts, all made of nitride steel. The piston pin is made of hardened steel and is kept in place with steel lock rings. The form of the piston is oval and tapered with plane piston top. By reducing the topland area (distance between upper piston ring to piston top), the hydrocarbon emissions from the engine to the catalytic converter have been reduced.

The pistons are oil cooled so that they can have a lower compression height. Oil is led through a valve in a longitudinal channel in the lower section of the cylinder block on the exhaust side. There is a nozzle screwed to the channel at each cylinder. This leads the oil towards the underside of the piston.

Camshafts, Valve system

The camshafts are cast iron. The cam lobes which press against the valve lifters are hardened to tolerate the contact pressure. The valve lifters are steel and mechanical, not hydraulic.

There is a certain amount of valve clearance between the valve lifters and cam lobes. The valve clearance is adapted to compensate for differences in length between the valve and cylinder head due to expansion when warming up. Mechanical valve lifters ensure more precise valve timing, reduced friction, more stable combustion and reduced mass.

The material in the lifters is case-hardened steel. The surfaces between the camshaft and valve are slightly convex to guarantee centered contact.

Camshaft transmission

The timing belt that drives both camshafts and the coolant pump is a conventional single-tooth belt. The camshafts' belt pulleys are secured with three screws in each camshaft. The holes for the screws are oval to enable correct setting of the camshafts' position. Tensioning of the timing belt is obtained using a mechanical belt tensioner. The belt tensioner presses on the belt via a tensioner roller mounted on a lever. The idler roller on the belt's other side prevents the belt from starting to vibrate.

Mechanical belt tensioner

The tensioner consists or a spring and a friction element. The friction element provides the required damping to absorb small oscillations and speed variations. The spring ensures correct belt tension, irrespective of wear and temperature. The belts are made of cord reinforced rubber.

Auxiliaries belt

1. Alternator
2. Servo pump
3. Air conditioning (A/C) compressor

The auxiliary units consist of two belts and three auxiliary units. The auxiliary units (alternator, servo pump and AC compressor) are driven by two Poly-V drive belts. The main belt, which drives the servo pump and alternator, is tensioned by a mechanical belt tensioner mounted on the cylinder block. The belt that drives the AC compressor via a belt pulley on the servo pump is of "flexible" type and thus there is no belt tensioner.

Lubrication system

The oil is led from the oil pan via a suction piece to the oil pump. The oil pump is located on the cylinder block. The oil is then pumped onwards to the oil cooling system and then to the oil filter. The oil flows from the filter through a cast oil duct in the intermediate section to the main bearings. The oil then flows through drilled channels in the crankshaft to the connecting rod bearings.

The camshafts are supplied with oil by a bored channel in the cylinder block. The channel runs through the cylinder head, where it flows out at the bottom of the upper half of the cylinder head. There is a cross duct in the channel to the cylinder head which carries oil to the pistons via a piston cooling valve.

The oil flows on via an oil duct to the bearing for the left-hand camshaft and the valve lifters (intake side). The bearings for the right-hand side camshaft (exhaust side) are supplied by a cast cross duct at the front edge of the upper half. This cast cross duct also supplies pressurized oil to the solenoids for the VVT unit. Drain holes in the cylinder block release the oil from the cylinder head and crankshaft bearing back to the oil pan.

Oil filter

The oil filter holder is made of die cast aluminum. It is on the cold side of the engine. The oil filter cover is plastic. There is a by-pass valve in the cover. An O-ring in the cover ensures that it is sealed.

Piston cooling valve

The piston cooling valve is manufactured in steel with a hardened piston, a spring and a spring stop. A copper washer ensures that oil does not leak onto the cylinder block.

Intake system

The inlet system is divided into two parts, the upper and lower inlet manifold. The upper inlet manifold is made of plastic, and the lower inlet manifold is made of aluminum as this is to protect the fuel injectors in case of a collision.

The inlet system has short pipes and a total capacity of 3.0 liters.

The gasket between the lower inlet manifold and cylinder head is a double gasket with built-in non-return valve.

Throttle body

The throttle housing is die-cast in aluminum. The throttle disc is also made of aluminum. Under the plastic cover there are position sensors that read off the position of the throttle disc as well as two motor connections to the motor that turns the throttle disc, depending on the driver's requested throttle disc angle.

The throttle body (TB) does not need to be cooled, but may need to be heated. An O-ring in the intake manifold ensures the seal between the intake manifold and throttle body (TB).

Turbocharger (TC)

The integrated manifold and turbine housing are made of austenite forged steel to tolerate exhaust temperatures up to 1050 °C.

The bearing housing and turbine housing are held together by a V-shaped clamp. The compressor housing is made of die cast aluminum. The bearing housing is cooled by the oil and coolant system to prevent coking in the bearing for the turbine shaft which spins at up to 170,000 rpm.

Flame trap

The flame trap is made of die cast aluminum and integrated with the oil filter. The cyclone separators are plastic and cannot be replaced.

Cooling system

The coolant pump pumps coolant through the cylinder block, and also cools the cylinder head, cylinder sleeves, spark plug wells, intake ducts and fuel injection nozzles.

The coolant flows in at the pump and passes through a number of channels before it collects and then flows out to the thermostat housing. If the thermostat housing is closed, the coolant passes via the by-pass channel directly to the coolant pump to then circulate through the cylinder block again.

In principle, the oil cooler looks the same for the engine as for transmission. An inlet for oil with outlet, also for the coolant. The oil cooler is built in layers where water and oil flow around each other. Due to the very small spaces in the oil coolers, there is a great pressure-drop. When the fuel is combusted in the car's engine, both mechanical work and excess energy are produced. The excess heat is lead away from the engine in the exhausts, through convection to the air in the engine compartment and through transferring to the coolant as well as via the engine oil. The cooling is a closed system.

Oil cooler

The radiator is made of aluminum to tolerate the thermal variances when the radiator is being both cooled by cool air and heated by hot coolant.

Thermostat

The thermostat is in the thermostat housing which is in the connection to the coolant outlet from the cylinder head. At the heart of the thermostat is a wax body which expands with energy in the form of heat. In modern cooling systems, the thermostat begins to expand when the surrounding coolant temperature is 90 °C.

Applies to: 2008–2010; D4204T

Engine, general

See: Engine, general

Lubrication system

Oil pump

1. Oil pump chain wheel
2. Oil pump housing
3. Oil screen
4. Pressure reduction valve
5. Mounting screws
6. Blind cover plug.

The oil pump is located on the transmission side of the engine, in the oil trough.

An oil pressure control valve is built into the oil pump housing. This valve opens at an oil pressure of approximately 800 kPa.

The oil pump is a rotor pump. It is powered by the camshaft via a short chain.

Oil filter

1. Oil filter housing
2. Oil cooler

The oil filter is a filter insert. There is a duct in the oil filter housing that is exposed when the oil filter is disassembled. Any remaining oil runs down into the oil pan and further spillage is eliminated.

The oil cooler is a plate oil cooler. The unit is connected to the coolant system. The coolant is routed through the oil cooler and on to the thermostat housing.

The oil cooler is also a coolant heat exchanger. The unit is located on the side of the cylinder block, level with cylinder 2.

There is a blind cover plug on the oil filter insert for sealing the drain hole for the oil filter housing.

When replacing the oil filter cartridge, the plug is pulled out together with the oil filter cartridge. The oil can run back to the oil trough via the housing, which mean that contaminants through leaking oil are prevented.

The unit is connected directly to the engine cooling system via a connection and a hose.

Oil pressure switch

1. Oil pressure switch

The oil pressure switch is located to the right by the oil cooler.

The minimum oil pressure of 50 kPa is monitored via the oil pressure switch. If this pressure is not achieved, the oil filter remains closed for safety reasons. The switch is connected via a conventional cable to the engine control module (ECM).

Oil injection pipes

1. Banjo screws
2. Oil injection pipes

The piston heads are cooled from beneath with oil from the oil injection pipes. The oil injection pipes are secured with banjo screws in the cylinder block.

The banjo screws are connected to the engine lubrication circuit.

The banjo screws contain valves that open the supply to the oil injection pipes when the oil pressure is approximately 50 kPa.

Fuel system

1. Fuel volume control valve

2. High pressure pump

3. Fuel pressure control valve

4. Drive shaft with eccentric

5. Internal feed pump

A. Fuel return

B. Connection for fuel rail

C. Inlet from the tank

The pump consists of the following main components:

• Internal feed pump that draws fuel from the tank via the fuel filter to the high-pressure pump. The feed pump also supplies the high-pressure pump with fuel for lubrication. The pump is a vane-type pump
• The fuel volume control valve, which regulates the fuel flow to the high-pressure pump according to the current need
• The high-pressure pump, which supplies the fuel rail and the injectors with fuel at high pressure
• The fuel pressure control valve, which regulates the fuel pressure from the high-pressure pump before the fuel reaches the fuel rail and the injectors.

1. Injector
2. Fuel dosing valve
3. High-pressure control valve
4. Diesel pump
5. Fuel rail
6. Fuel pressure sensor.

The engine has a common rail injection system from Siemens.

The diesel pump contains an integral feed pump, which feeds the fuel from the tank to the diesel pump.

Diesel pump

1. High-pressure outlet for fuel rail
2. Inlet from fuel filter
3. Fuel volume control valve
4. Return to fuel tank
5. High-pressure control valve

The diesel pump is located on the transmission side of the cylinder head and is powered directly by the exhaust camshaft via a flange.

The diesel pump has three high-pressure pump elements that are located with a 120° separation.

The feed pump is integrated in the diesel pump and is located on the flange. The feed pump is a vane-type pump.

The fuel dosing valve is located in the inlet channel between the high-pressure pump elements and the feed pump. It is controlled via pulse width modulation by the engine control module (ECM).

The three high-pressure outlets for the high-pressure pump elements have been brought together into a single high-pressure connection.

The high-pressure control valve is located by the high-pressure bore for the fuel rail. The fuel pressure regulator is activated by the engine control module (ECM).

Fuel rail

1. Fuel pressure sensor.

The fuel rail is made from forged steel and is mounted directly in the cylinder block.

The fuel is supplied from the diesel pump to the fuel rail via a single delivery line.

From the fuel rail, the fuel is led to the injectors via four more delivery lines.

Fuel filter

1. Inlet from fuel tank
2. Connection to diesel pump
3. Electrical fuel preheating
4. Drain screw.

The fuel filter is located above the fuel rail and is mounted in a holder on the cylinder head.

The fuel filter has electrical fuel preheating, which is located in the middle of the filter, between the inlet and the outlet connections.

The fuel filter and the housing constitute a single unit that can only be replaced as a complete unit.

The fuel filter has collision protection.

Injectors

1. Delivery line connection
2. Connector
3. Retainer
4. Copper seal
5. Plastic socket
6. Return line connection.

The injectors are located in the center of the top of the cylinder head, and are secured in holders.

The guide sleeves in the lower section of the cylinder head and the plastic sleeves for the injectors provide correct centering.

The seal with the combustion chamber is provided with a copper washer between the injector and the cylinder head. This must always be replaced when installing.

The return lines are secured on the top of the injectors and connected in series to each other.

The use of piezoelectrical material for controlling the injection sequences provides a number of benefits compared to injectors that work with electromagnetism:

• up to four times faster
• only one impulse is required to start injection and one impulse to terminate injection
• low power consumption
• the combination of low current and impulse control means that less energy is required for each injection sequence
• the speed means that the injection times can be controlled extremely precisely, which ensure great accuracy as regards the amount of injected fuel
• the system is not sensitive to electromagnetic effects.

Additive tank, applies to S40 (04-), V50, C30 and C70 (06-)

1. Additive Dosing Module (ADM)
2. Additive tank with integrated pump and level sensor
3. Ventilation valve for tank
4. Feeder hose and injector
5. Main fuel tank (diesel)
6. Overflow valve (when filling)
7. Refilling connection for additive

The additive system consists of the additive dosing module (ADM), additive tank, a mechanical injector on the main fuel tank and the feeder hose for additive.

The additive tank is made of polyethylene plastic.

The additive tank has a refilling connection for additive and a ventilation valve. The tank has an overflow valve. This valve releases any excess additive during refilling when the tank is full. There is a pump and level sensor inside the additive tank.

The pump is integrated in the additive tank. It is positioned on the side of the tank housing. The pump cannot be replaced as a separate component. The entire additive tank must be replaced as a single unit.

The level sensor provides the additive dosing module (ADM) with information about the prevailing additive level in the separate tank. The level sensor is integrated in the additive tank. It is positioned on the bottom of the tank housing. The level sensor cannot be replaced as a separate component. The entire additive tank must be replaced as a single unit.

For more information, see Design and Function, Additive Dosing Module (ADM).

Vacuum system

Overview

Hose 1

Hose 2

Hose 3

Hose 4

EGR system

1. Exhaust gas recirculation (EGR) cooler
2. Connector pipe to intake manifold
3. Connector pipe to valve cover / air cleaner (ACL)
4. EGR stepper motor
5. Connection to the cylinder head.

The EGR system consists of an EGR stepper motor, and EGR cooler and a connector pipe to the intake manifold.

Catalytic converter

The catalytic converter is an oxidation catalytic converter which reduces CO and HC emissions.

Its location, immediately after the turbocharger (TC), known as a CCC (Closed Coupled Catalyst), means that the catalytic converter rapidly reaches the correct operating temperature.

Turbocharger (TC)

1. Turbocharger (TC) position sensor
2. Turbocharger (TC) housing
3. Gasket
4. Adapter
5. Oil return hose
6. Retainer
7. Banjo screw
8. Oil line
9. Banjo screw

The turbocharger (TC) control valve steplessly regulates the vacuum in the pressure regulator which control the turbine position, (Variable Nozzle Turbine, VNT).

In principle the valve can vary the pressure from absolute vacuum to atmospheric pressure. This allows the guide rails for the turbocharger (TC) to be regulated steplessly, which means that the desired boost pressure can be achieved.

The engine control module (ECM) controls the position of the control valve and hence also the position of the valve.

Cooling system

Coolant circuit

1. Heat exchanger
2. Thermostat housing
3. Bypass valve (S40 (04-), V50 -2005)
4. Thermostat
5. Shut-off valve
6. Oil cooler
7. Coolant heat exchanger
8. Cooling system expansion tank
9. Cylinder block
10. Coolant Pump
11. Exhaust gas recirculation (EGR) cooler

The coolant flow is dependent on the following components:

• bypass valve (3)
• thermostat (4)
• shut-off valve (5)
• engine coolant temperature (ECT) sensor
• engine control module (ECM).

Due to the high efficiency of the diesel engine and consequently the relatively small heat losses, it can be difficult to maintain a comfortable temperature in the passenger compartment at low outside temperatures. The purpose of the various components is, on the basis of the coolant temperature, to regulate the coolant flow to the heater element in the passenger compartment so that coolant heating takes place as quickly as possible.

Thermostat housing

1. Bypass valve
2. Connection to the cooling system expansion tank
3. Connection to cooler inlet
4. Connection to coolant heat exchanger
5. Connection to cooler outlet
6. Connection to coolant pump
7. Connection to heat exchanger
8. Engine coolant temperature (ECT) sensor.

In order to achieve rapid heating of the coolant, and therefore a comfortable temperature in the passenger compartment, the engine cooling system has:

• a thermostat housing
• an electrically controlled bypass valve
• an electrically controlled shut-off valve.

The thermostat housing is located on the cylinder head on the transmission side of the engine.

The engine temperature sensor is located in the thermostat housing and is secured with a clip. The thermostat housing also houses the thermostat and the bypass valve. The thermostat is a conventional type.

The thermostat housing is made of plastic and cannot be dismantled during service work. The engine coolant temperature (ECT) sensor can be replaced separately.

For further information about the components, see Design and Function, engine control module (ECM).

Coolant Pump

1. Gasket
2. Coolant Pump

The coolant pump is located on the transmission side of the engine and is powered via a toothed belt.

The coolant pump housing consists of an aluminum alloy and is secured using 5 screws.

The pump housing is made of an aluminum alloy. The gear wheel is made of plastic. The gasket between the pump and the cylinder block comprises a metal frame that is coated with rubber.

A rubber-coated metal gasket is used for the coolant pump seal with the cylinder block.

Applies to: 2008–2011; B4204S3, B4204S4

Engine, general

The engine has a variable intake system and an ignition system with directly installed ignition coils. This means that the torque has been increased over the entire rev range at the same time as reducing the fuel consumption.

The engine has mechanical valve lifters and electronic throttle. It has a stepper motor controlled EGR system.

The compact "pent roof" design of the combustion chamber and the V shaped arrangement of the valves provides optimize injection and evacuation. It also provides direct evacuation via the intake passage followed by the combustion chamber (cross-flow) and the exhaust passage. The swirl surfaces of the combustion chamber and the centrally positioned spark plug ensures optimal combustion, low sensitivity to knocking and low, stable exhaust emissions.

It has knock control with knock sensors.

The engine is pendulum mounted on an engine bracket which is secured to the side member. The other mounting bracket is on the transmission and side member.

The sequence for the cylinders starts at the flywheel with cylinder 1.

The bioethanol engine has closer service intervals than the gasoline engine.

The engine has integrated diagnostics for monitoring the exhaust related components. Diagnostics are carried out via the data link connector.

For information on the engine control module (ECM), sensors, and valves, see Design and Function, Engine Control Module (ECM).

Cylinder head and camshafts

The cylinder block is made from an aluminum alloy. It is reinforced to increase rigidity. The bearing shells are secured by bolts on a separate bridge.

The pistons are made of a light-metal alloy and are graphite covered to reduce friction, noise and vibration.

The exhaust circulation pipes are integrated in the cylinder head.

The water cooled EGR valve is on the side of the cylinder head and is checked by an electric motor.

The bioethanol engine has a new cylinder head with new valve seats on the intake side. These components have a harder surface coating to maintain the service life, as bioethanol (E85) has a corrosive effect.

The exhaust valves lean 10 degrees from vertical. The intake valves lean 19 degrees. The asymmetric layout makes it possible to use larger valve diameters.

Double overhead camshafts directly affect the valve stem via the valve lifter.

The camshafts are driven by the crankshaft by a chain that has a fixed guide on the slack side and a hydraulic tensioner on the driven side to maintain valve times and reduce noise. There is also a chain with a spring loaded tensioner that drives the oil pump. The system is maintenance free during the service life of the engine. Both the chain guide and the chain tensioner have plastic inserts on the runners to ensure quiet operation.

Camshaft operation

1. Exhaust side's camshaft pulley
2. Camshaft chain
3. Intake side's camshaft pulley
4. Chain guide
5. Crankshaft pulley
6. Hydraulic chain tensioner
7. Chain tensioner arm

The engine has chain driven camshafts. The camshaft chain is tensioned by a hydraulic chain tensioner that is supplied with oil from the engine oil circuit.

The double overhead camshafts are driven by the camshaft by a maintenance free chain drive.

The camshaft drive is covered by an aluminum front. The camshaft's oil seal is integrated in the aluminum front, which is installed with the seal.

The valve lifters are made of steel and are mechanical, not hydraulic.

The material in the valve lifters is case-hardened steel. The surfaces between the camshaft and valve are slightly convex to guarantee centered contact.

The camshaft's sprocket is attached by 4 screws in each camshaft.

Intake manifold

1. EGR gasket
2. Gasket for intake manifold
3. Swirl throttle
4. Connection pipes
5. Vacuum regulator for swirl damper
6. Control arm

The intake pipe consists of three welded shells made of glass fiber polyamide plastic. The base material is mixed with a large proportion of recycled material.

The intake pipe has integrated swirl dampers that reduce the cross-section on the inlet at low speeds. This produces an increased intake of air at low engine speeds.

The increased intake causes the mixture to ignite nearer the spark plug, which means lower fuel consumption and less exhaust gases.

The swirl dampers are adjusted by a vacuum regulator by the intake manifold.

The system is affected by a solenoid. The swirl dampers allow the correct amount of air the pass. When the engine is switched off the swirl dampers are open.

On the upper section of the swirl damper, there is a spring that ensures that the engine receives air even when the swirl damper is fully closed.

The intake manifold is sealed by five rubber gaskets, four for the intake pipes and one for the EGR connection. These must be replaced at service.

The circulating exhaust gases are evenly distributed between the four intake pipes for the fuel rail.

The intake pipe optimizes gas exchange and minimizes the noise level.

The intake pipe is designed for volumetric efficiency at full load and optimal EGR recirculation for all relevant driving conditions.

Crankshaft

1. Crankshaft
2. Crankshaft seal
3. Front cover
4. Vibration damper
5. Center screw for the crankshaft
6. M6 screw

The crankshaft is made of cast iron. It has five shaft bearings and four counter weights.

The crankshaft's vibration damper is in the same unit as the rotor, which indicates the crankshaft's position. It is secured at the crankshaft by a clamping bolt.

The center screw must be replaced if it is removed. The vibration damper is adjusted into place using an M6 screw. This screw must not be used as a support when tightening the center screw, as this can damage the cam cover.

Connecting rod

The connecting rod is made of sintered steel. The narrow end is stepped to minimize weight and therefore the mass forces.

The big end is very well dimensioned and does not need dividing into different weight classes.

Piston

The piston is optimized for low weight. The first oil channel is hard-anodized to reduce wear.

The piston pin is case-hardened and has a conical inner contour to reduce its weight. The piston skirt is covered in graphite to reduce friction and play, which also reduces noise.

The pistons are cooled by oil from the spray nozzles that are integrated in the diaphragm between the main bearings.

Dual mass flywheel

The engine is designed to minimize noise and vibration. The engine is therefore equipped with a dual mass flywheel.

Cylinder head cover

1. Oil filler cover
2. Mounting for ignition coil
3. Camshaft position sensor

The oil filler cover is secured on the valve cover by a bayonet lock.

Cylinder block

The cylinder block is cast in aluminum alloy. It is designed to increase stability.

The cylinder block has four cast-iron cylinder liners cast in the cylinder block and cannot be replaced.

The oilway and drain plug are cast in the cylinder block.

An aluminum bearing bridge contributes to the high rigidity and provides a stable lower mounting for the clutch cover.

The cylinder walls run down over the crankshaft center to increase rigidity. The cast-iron cylinder sleeves are accurately cast in the aluminum block.

Valve system

The double overhead camshafts have five main thrust bearings and are made of cast-iron.

The cam lobes act directly on the valve stem via mechanical valve lifters.

Shims are not required to adjust valve clearance. Instead, graded valve lifters are already installed during production to achieve the correct valve clearance.

The contact surfaces of the valve lifters are covered in phosphate, which provides better lubrication and minimizes wear.

The valve stem is nitrated to reduce wear.

All components in the valve system are designed with low weight. The valve system is maintenance free during the service life of the engine.

The camshaft profile is optimized for the contact forces between the cam flank and the valve lifters.

Oil pan

1. Protective cover

A protective cover is installed under the A/C compressor.

The oil sump is made of die cast aluminum. The cylinder block and oil sump are optimized for low noise levels and maximum rigidity.

Lubrication system

The oil pump is mounted in the cylinder block and is chain driven via the crankshaft. Nozzles spray oil onto the underneath of the pistons to cool the pistons down.

The oil is led from the oil pan via a suction piece to the oil pump. The oil pump is located on the cylinder block. The oil is then pumped onwards to the oil cooling system and then to the oil filter. The oil flows from the filter through a cast oil duct in the intermediate section to the main bearings. The oil then flows through drilled channels in the crankshaft to the connecting rod bearings.

The camshafts are supplied with oil by a bored channel in the cylinder block. The channel runs through the cylinder head, where it flows out at the bottom of the upper half of the cylinder head. There is a cross duct in the channel to the cylinder head which carries oil to the pistons via a piston cooling valve.

The oil flows onwards via an oil duct to the bearing for the left-hand camshaft and the valve lifters (intake side). The bearings for the right-hand side camshaft (exhaust side) are supplied by a cast cross duct at the front edge of the upper half. Drain holes in the cylinder block release the oil from the cylinder head and crankshaft bearing back to the oil sump.

Oil pump

1. Oil pump
2. Gasket
3. Outer rotor
4. Inner rotor

The oil pump is of the rotor type. The oil pump lubricates the engine. It runs smoothly and can create the high pressure that is necessary for optimum lubrication.

Oil filter

1. Gasket
2. Oil pressure contact
3. Oil filter housing
4. Oil filter

The oil filter holder is made of die cast aluminum. It is on the cold side of the engine, on the cylinder block. The oil filter is a metal filter, which is replaced as one unit.

Fuel system

The gasoline engines run on RON 95 fuel.

The bioethanol engine is a flexifuel engine and runs on bioethanol (E85) or RON 95 fuel and all possible mixtures of these two fuels.

The engine is equipped with a non-return fuel system.

Bioethanol engine

The bioethanol engine has a new fuel rail compared to the gasoline engines. The intake pipe has a harder surface coating to maintain the service life, as bioethanol (E85) has a corrosive effect. The valve clearance is slightly less and the injectors have a greater capacity than in the gasoline engine.

Exhaust system

The exhaust system primarily consists of four sections: manifold, three-way catalytic converter (TWC), heated oxygen sensors (HO2S) and muffler. The exhaust system is manufactured from chromium steel sections welded together.

The pipes are specific lengths so that the gases flowing from the cylinders do not interfere with each other and so that there is also good flow distribution in the three way catalytic converter (TWC). There is a boot on the three way catalytic converter (TWC) to absorb engine movements and any manufacturing and installation tolerances.

The entire exhaust system is manufactured in chromium steel. A three-way catalytic converter (TWC) consists of perforated ceramic beads or metal substrates. These are coated with a Wash-coat and then a further coating of the catalytic inert metals, platinum, palladium and rhodium. Heated oxygen sensors (HO2S) are used to control the engine and monitor the three-way catalytic converter (TWC). There is one heated oxygen sensor (HO2S) before and one heated oxygen sensor (HO2S) in the three-way catalytic converter (TWC).

The three-way catalytic converter (TWC) consists of a metal monolith and is located directly on the exhaust manifold. The location halves the heating time during cold starts. This reduces cold emissions.

Exhaust pipe

The exhaust pipe is welded stainless steel pipes. Low weight and high heating capacity are achieved by thin pipe walls.

Cooling system

The radiator is made of aluminum to tolerate the thermal variances when the radiator is being both cooled by cool air and heated by hot coolant.

The cooling system is controlled by a mechanical thermostat. The cooling system expands when energy, in the form of heat, is supplied.

The coolant pump pumps coolant through the cylinder block, and also cools the cylinder head, cylinder sleeves, exhaust bridge spark plug wells, intake ducts.

The coolant flows in at the pump and passes through a number of channels before it collects and then flows out to the thermostat housing. If the thermostat housing is closed, the coolant passes via the by-pass channel directly to the coolant pump to then circulate through the cylinder block again.

When the fuel combusts in the vehicle's engine, the result is both mechanical work and excess energy. The excess heat is taken away from the engine via the exhaust gases by convection to the air in the engine compartment and also by transfer to the coolant and engine oil. The cooling system is a closed system.

Thermostat housing

1. Thermostat housing
2. By-pass hose

The mechanical thermostat allows the engine's cooling temperature to adjust according to the engine's requirements.

Lower cooling temperatures are required at full load. A high cooling temperature is associated with a high oil temperature.

Auxiliaries belt

S40, V50, C30

The alternator is driven by a separate Poly-V belt and has a mechanical belt tensioner. The coolant pump is also driven by this belt.

The low mounted AC compressor is driven by an elastic Poly-v belt without belt tensioner.

S80 (07-), V70 (08-)

The generator, AC compressor, servo pump and coolant pump are driven by the crankshaft via a common auxiliaries belt.

Applies to: 2009–2011; B5254T11, B5254T8

Engine

The entire engine is made of aluminum.

The engine has a compact "pent-roof" designed combustion chamber and V-arranged valves. This gives optimal and fast filling and direct flushing via the inlet manifold followed by the combustion chamber (cross-flow) and the exhaust channel.

The squish surfaces together with the centrally positioned spark plug provide optimal combustion of the air/fuel mixture, low knock sensitivity and low, stable exhaust emissions.

Unique spark plugs made from materials with high corrosion resistance are used.

The engine's oscillation-mounting consists of an engine bracket bolted in the cylinder head. The engine bracket meets a bracket which is secured in the side member. The other attaching point is located between the transmission and body. A third attaching point for absorbing reaction forces and rotational forces in the bearing bracket for the drive shaft.

The cylinder head is "chill" cast, a slightly slower procedure than die-casting. This is so to integrate exhaust, inlet channel, water and oil casing in the design.

The engine is approved according to emission requirements Euro 5. All bearings are lead-free. Screws are Crome 6+ -free.

The Bioethanol engine is a flexifuel engine. The engine has a new cylinder head with new valve seats on the inlet side and a new fuel rail compared to the gasoline engine. The fuel rail and schrader valve for draining the fuel system are made of stainless steel. These parts have harder surface coatings in order to retain service life because bioethanol (E85) has a corrosive effect. The EVAP and fuel pipes are partially covered by a Kevlar cover as protection against the higher temperature of the catalytic converter.

Valve play is slightly less and the fuel injection supply manifolds have more capacity than on a petrol engine. The bioethanol engine has closer service intervals than a petrol engine

The petrol engine is powered by RON 95 fuel. The bioethanol engine is a flexifuel engine and is powered by bioethanol (E85) or RON 95 fuel and all possible mixtures of these two fuels.

The bioethanol engine has a pre-mounted engine block heater that should be used to facilitate starts at low temperatures, In addition, the amount of gasoline in the fuel mixture should increase at temperatures lower than -10°C, to facilitate cold starts. Because bioethanol has a lower energy content than gasoline the engine uses up 40 % more bioethanol compared with gasoline.

Engine block

1. Cylinder head cover
2. Cylinder head
3. Cylinder block
4. Intermediate section
5. Oil pan

The engine block is divided into five parts, where the cylinder head consists of two parts (1 and 2) and the engine block of three parts (3, 4 and 5). The seal between the cylinder head and engine block is a conventional cylinder head gasket, while sealing between the other gasket surfaces is done with liquid gasket.

Cylinder head, camshaft bearing housing

The two camshafts are carried in six bearing races each directly in the cylinder head's two halves. The upper half functions as a combined valve cover and camshaft cap. It has cast oil distribution pipes on the underside which ensures good oil supply to the camshafts and the mechanical valve depressors. The lower half has the maintenance-free mechanical valve depressors, valve springs and valves.

Cylinder block

The engine block is divided into three sections, the cylinder block, intermediate section and oil pan. The mating flange between the cylinder block and intermediate section is in the center line of the crankshaft.

The cylinder block has five cast iron cylinder sleeves cast into the cylinder block which cannot be replaced. The six main bearing seats have cast iron reinforcements in the intermediate section.

On the top of the intermediate section there are cast oil channels which distribute the oil to the main bearings and on via the crankshaft to the big ends.

The oil pan contributes to the rigid construction and acts as additional reinforcement. There is central smooth-bore oil duct for piston cooling.

Oil pan

The oil sump is made of die-cast aluminum with baffles. This is so that the oil will not move too heavily. It is secured in the cylinder block and in between there is a liquid gasket LOCTITE, which ensures sealing between the cylinder block and oil sump. The oil suction line running from the sump is made of plastic. The oil sump is provided with an oil level sensor.

Crankshaft

The crankshaft has six main bearings. The 5th main bearing is a throw-out bearing. At the front end of the crankshaft are two spline joints, the inner of which drives the oil pump. The drive gear for the timing belt and vibration damper is on the outer joint.

Blind splines gives the right position and guides the drive gear. The connecting rods are forged and the cracked joint between the connecting rod and cap provides exact fixation of the caps. The forged crankshafts give maximal strength at the same time as they contribute to a low sound level.

Piston

The piston has a uniform aluminum alloy with graphite coating on the sides. This coating gives a certain friction reduction as well as noise damping. The piston rings are of different materials depending on where they are mounted on the piston.

The upper compression ring has a chromed nitrided steel ring. Together with the anodising of the piston's upper ring groove is an adaptation for ethanol operation. Ethanol operation periodically causes a major fuel dilution of the engine oil which leads to reduced lubrication. Together with the high mechanical and thermal loads the reduced lubrication increases the risks of engine damage.

The lower compression ring is made of cast iron and the oil scraper ring is a design consisting of three parts, all made of nitride steel. The piston pin is made of hardened steel and is kept in place with steel lock rings.

The pistons are oil cooled so that they can have a lower compression height. Oil is led through a valve in a longitudinal channel in the lower section of the cylinder block on the exhaust side. There is a nozzle screwed to the channel at each cylinder. This leads the oil towards the underside of the piston.

The form of the piston is oval and tapered with plane piston top. By reducing the topland area (distance between upper piston ring to piston top), the hydrocarbon emissions from the engine to the catalytic converter have been reduced.

Camshafts, Valve system

The camshafts are cast iron. The cam lobes which press against the valve lifters are hardened to tolerate the contact pressure. The valve lifters are steel and mechanical, not hydraulic.

The exhaust valve is adapted for turbo operation and has a valve stem material that can withstand high exhaust temperatures. The inlet valve has a stainless steel valve stem material to prevent corrosion.

The valve seats are made from a hard material to tolerate high stresses.

There is a certain amount of valve clearance between the valve lifters and cam lobes. The valve clearance is adapted to compensate for differences in length between the valve and cylinder head due to expansion when warming up. Mechanical valve lifters ensure more precise valve timing, reduced friction, more stable combustion and reduced mass.

The material in the lifters is case-hardened steel. The surfaces between the camshaft and valve are slightly convex to guarantee centered contact.

Camshaft transmission

The timing belt that drives both camshafts and the coolant pump is a conventional single-tooth belt. The camshafts' belt pulleys are secured with three screws in each camshaft. The holes for the screws are oval to enable correct setting of the camshafts' position. Tensioning of the timing belt is obtained using a mechanical belt tensioner. The belt tensioner presses on the belt via a tensioner roller mounted on a lever. The idler roller on the belt's other side prevents the belt from starting to vibrate.

Mechanical belt tensioner

The tensioner consists or a spring and a friction element. The friction element provides the required damping to absorb small oscillations and speed variations. The spring ensures correct belt tension, irrespective of wear and temperature. The belts are made of cord reinforced rubber.

Auxiliaries belt

1. Alternator
2. Servo pump
3. Air conditioning (A/C) compressor

The auxiliary units consist of two belts and three auxiliary units. The auxiliary units (alternator, servo pump and AC compressor) are driven by two Poly-V drive belts. The main belt, which drives the servo pump and alternator, is tensioned by a mechanical belt tensioner mounted on the cylinder block. The belt that drives the AC compressor via a belt pulley on the servo pump is of "flexible" type and thus there is no belt tensioner.

Lubrication system

The oil is led from the oil pan via a suction piece to the oil pump. The oil pump is located on the cylinder block. The oil is then pumped onwards to the oil cooling system and then to the oil filter. The oil flows from the filter through a cast oil duct in the intermediate section to the main bearings. The oil then flows through drilled channels in the crankshaft to the connecting rod bearings.

The camshafts are supplied with oil by a bored channel in the cylinder block. The channel runs through the cylinder head, where it flows out at the bottom of the upper half of the cylinder head. There is a cross duct in the channel to the cylinder head which carries oil to the pistons via a piston cooling valve.

The oil flows on via an oil duct to the bearing for the left-hand camshaft and the valve lifters (intake side). The bearings for the right-hand side camshaft (exhaust side) are supplied by a cast cross duct at the front edge of the upper half. This cast cross duct also supplies pressurized oil to the solenoids for the VVT unit. Drain holes in the cylinder block release the oil from the cylinder head and crankshaft bearing back to the oil pan.

Oil filter

The oil filter holder is made of die cast aluminum. It is on the cold side of the engine. The oil filter cover is plastic. There is a by-pass valve in the cover. An O-ring in the cover ensures that it is sealed.

Piston cooling valve

The piston cooling valve is manufactured in steel with a hardened piston, a spring and a spring stop. A copper washer ensures that oil does not leak onto the cylinder block.

Intake system

The inlet system is divided into two parts, the upper and lower inlet manifold. The upper inlet manifold is made of plastic, and the lower inlet manifold is made of aluminum as this is to protect the fuel injectors in case of a collision.

The inlet system has short pipes and a total capacity of 3.0 liters.

The gasket between the lower inlet manifold and cylinder head is a double gasket with built-in non-return valve.

Fuel pump, tank unit

The tank unit has a sealed contact ring to prevent corrosion

The fuel pump is demand controlled and has an integrated filter

Throttle body

The throttle housing is die-cast in aluminum. The throttle disc is also made of aluminum. Under the plastic cover there are position sensors that read off the position of the throttle disc as well as two motor connections to the motor that turns the throttle disc, depending on the driver's requested throttle disc angle.

The throttle body (TB) does not need to be cooled, but may need to be heated. An O-ring in the intake manifold ensures the seal between the intake manifold and throttle body (TB).

Turbocharger (TC)

The integrated manifold and turbine housing are made of austenite forged steel to tolerate exhaust temperatures up to 1050 °C.

The bearing housing and turbine housing are held together by a V-shaped clamp. The compressor housing is made of die cast aluminum. The bearing housing is cooled by the oil and coolant system to prevent coking in the bearing for the turbine shaft which spins at up to 170,000 rpm.

Flame trap

The flame trap is made of die cast aluminum and integrated with the oil filter. The cyclone separators are plastic and cannot be replaced.

Cooling system

The coolant pump pumps coolant through the cylinder block, and also cools the cylinder head, cylinder sleeves, spark plug wells, intake ducts and fuel injection nozzles.

The coolant flows in at the pump and passes through a number of channels before it collects and then flows out to the thermostat housing. If the thermostat housing is closed, the coolant passes via the by-pass channel directly to the coolant pump to then circulate through the cylinder block again.

In principle, the oil cooler looks the same for the engine as for transmission. An inlet for oil with outlet, also for the coolant. The oil cooler is built in layers where water and oil flow around each other. Due to the very small spaces in the oil coolers, there is a great pressure-drop. When the fuel is combusted in the car's engine, both mechanical work and excess energy are produced. The excess heat is lead away from the engine in the exhausts, through convection to the air in the engine compartment and through transferring to the coolant as well as via the engine oil. The cooling is a closed system.

Oil cooler

The radiator is made of aluminum to tolerate the thermal variances when the radiator is being both cooled by cool air and heated by hot coolant.

Thermostat

The thermostat is in the thermostat housing which is in the connection to the coolant outlet from the cylinder head. At the heart of the thermostat is a wax body which expands with energy in the form of heat. In modern cooling systems, the thermostat begins to expand when the surrounding coolant temperature is 90 °C.