Volkswagen Passat teardown (1)

1.4L turbo-gasoline engine: Water-cooled intercooler and displacement management system

2016/10/31

Summary

Engine camshaft of the
Volkswagen Passat
Engine camshaft of the Volkswagen Passat

  A teardown analysis of the Volkswagen Passat (1.4L TSI Comfortline model for the Japanese market) was performed in September 2016 by the Hiroshima Industrial Promotion Organization. The Passat (the 8th-generation model: launched in 2014) received the 2015 European Car of the Year award for excellent driving performance, ride comfort, safety, and utility.

  The Passat is built on the MQB platform, which is also used by the 7th-generation Golf. The platform offers benefits including increased body rigidity and weight reduction that result in excellent dynamic performance, a comfortable ride, and cabin quietness. It is powered by a 1.4L direct injection single-turbocharger engine with a water-cooled intercooler, and delivers a maximum output of 110 kW (150 PS) and 250 Nm (25.5 kgm) of torque. Two of its four cylinders are left idle under low loads to achieve a JC08 mode fuel efficiency of 20.4 km/liter. This report focuses on the water-cooled intercooler, displacement management system, and other engine-related technologies that are featured on the Passat. The next report will focus on the body structure and other elements of the MQB platform.

Previous teardown reports:

Teardown of Toyota's Flagship Sedan
(Part 1) 2.5-liter V6 engine "4GR-FSE" (May 2016)
(Part 2) Chassis technology for high-end rear-wheel drive cars common to Toyota and Lexus vehicles (Jun. 2016)
(Part 3) High-rigidity body structure for crash safety, handling stability, and quietness (Sep. 2016)
(Part 4) Teardown of Toyota’s Flagship Sedan: Photo gallery (Oct. 2016)

4th-Generation Toyota Prius Teardown
(Part 1) Powertrain units miniaturized and lightened to achieve 40km/liter fuel economy (Feb. 2016)
(Part 2) New TNGA platform enhances dynamic performance; advanced aerodynamics and chassis technologies (Mar. 2016)
(Part 3) Body structure based on TNGA, sound insulating, absorbing and damping technologies (Apr. 2016)
Photo gallery (132 parts): Photographs of TNGA parts/components and a list of parts suppliers (May 2016)

Daihatsu Move (Feb./Mar. 2015)
(Part 1): Equipment comparable to B-segment cars
(Part 2): High fuel economy and improved performance
(Part 3): Linear body structure optimizes space

Honda Fit Hybrid (Dec. 2013)
(Part 1): Battery components & brake system
(Part 2): Engine and transmission

VW Polo (Nov./Dec. 2014)
VW Polo Teardown (Part 1)
VW Polo Teardown (Part 2)

Toyota Aqua (Nov. 2012)
Toyota Aqua (Prius c) teardown: Part 1
Toyota Aqua (Prius c) teardown: Part 2

Nissan Note (Sep. 2014)
Nissan Note (Versa Note) Teardown (Part 1)
Nissan Note (Versa Note) Teardown (Part 2)

Nissan Leaf
Nissan Leaf teardown (Part 1) (Feb. 2012)
(Part 2): main components disassembled (Sep. 2012)
(Part 3): body cutaway (Nov. 2012)

Honda Accord Hybrid (Feb. 2014)
Honda Accord Hybrid teardown (Part 1)
Honda Accord Hybrid teardown (Part 2)
Honda Accord Hybrid teardown (Part 3)



Precisely configured compact, downsized turbo-engine

Engine room viewed from
the vehicle's rear
Engine room viewed from the vehicle's rear
Engine room viewed from
the front left of the vehicle
Engine room viewed from the front left of the vehicle


  The 1.4L direct injection single-turbocharger engine is equipped with a water-cooled intercooler that is precisely fit into the engine room, which is common to all models built on the MQB platform. The intake line is laid out in the front of the vehicle and the exhaust line in the rear. Intake air enters the air duct at the front end of the engine room, passes through the air cleaner on top of the engine, and flows in the air duct to the turbocharger between the back of the engine and the dashboard panel. Turbocharged air is sent to the throttle body through the intake pipe at the top of the engine. The throttle body is located at the entrance to the intake manifold that the water-cooled intercooler is built into. The intercooler cools intake air, which is then sent from the intake manifold to the cylinder head.

Engine assembly viewed
from the vehicle's rear
Engine assembly viewed from the vehicle's rear
Engine assembly viewed
from the front left of the vehicle
Engine assembly viewed from the front left of the vehicle


Water-cooled intercooler system with short intake piping

Intake manifold and
throttle body
Intake manifold (cylinder head mounting surface) and throttle body
Intake manifold and
throttle body viewed from above the engine
Intake manifold and throttle body viewed from above the engine


  The intake manifold is located under the air cleaner positioned at the top of the engine. A water-cooled intercooler is built into the intake manifold, which has the throttle body fitted to it. Turbocharged air is sent directly from the turbocharger to the throttle body through the air intake pipe. Intercoolers are generally fitted in front of the radiator at the very front of the vehicle. This means the turbocharged air must travel a long distance, often as far as several meters, from the turbocharger to the intercooler, then back to the throttle body and intake manifold. In contrast, the water-cooled intercooler allows for a far shorter air travel distance while reducing the intake air volume. This reduces the inertial mass of intake air while at the same time improving accelerator response.

  The intake manifold is made of nylon (PA6 GF30) and has an aluminum intercooler built into it. Hot, turbocharged air from the throttle body is cooled as it travels in the aluminum intercooler. The intercooler core is 103 mm tall, 284 mm wide, and 55 mm deep. The intake manifold is manufactured by Polytec Group and the throttle body by Magneti Marelli. The nylon air intake pipe (PA6 GF30) is manufactured by Rochling.

Intake manifold without
the intercooler core
Intake manifold without the intercooler core
Water-cooled intercooler
connected to the intake manifold
Water-cooled intercooler connected to the intake manifold
Water-cooled intercooler
core
Water-cooled intercooler core
Air intake pipe
Air intake pipe (PA6 GF30 manufactured by Rochling)


  The coolant for the water-cooled intercooler has a dedicated radiator separate from the engine coolant. This special radiator is located in the front-end module together with the radiator for engine coolant. It is 420 mm wide, 622 mm tall, and 28 mm thick, which is nearly the same size as the engine coolant radiator (650 mm wide, 455 mm tall, 27 mm thick) that is located behind it. The front-end module has the air-conditioner condenser, radiator for the water-cooled intercooler and radiator for the engine coolant laid out in sequence from the vehicle's front.

Front-end module
Front-end module
Radiator for water-cooled
intercooler
Radiator for water-cooled intercooler (manufactured by MAHLE)
Water pump for the
water-cooled intercooler
Water pump for the water-cooled intercooler
Engine in place
Engine in place (without the front-end module)


Turbocharger (manufactured by Mitsubishi Heavy Industries)

Turbocharger (manufactured
by Mitsubishi Heavy Industries) Turbocharger (manufactured
by Mitsubishi Heavy Industries)
Turbocharger (manufactured by Mitsubishi Heavy Industries)


  The turbocharger, which is manufactured by Mitsubishi Heavy Industries, has a small-diameter turbine designed to start turbocharging at low speeds and deliver maximum torque from 1500 rpm to 3500 rpm. The air duct on the air cleaner side is shaped to ensure resonance effects. Presumably the purpose for this is to reduce vibrational resonance noise or airflow resistance caused by the resonance of intake air. It is a simple structure that lacks features like twin scrolls and variable geometry.

Turbocharger installed in
the engine
Turbocharger installed in the engine
Boost pressure control
valve and exhaust gas turbine
Boost pressure control valve and exhaust gas turbine


Displacement management system (Active Cylinder Technology)

Intake/exhaust camshafts
Intake/exhaust camshafts built into the cam carrier-integrated cylinder head cover
Exhaust camshaft slide
mechanism
Exhaust camshaft slide mechanism


  The engine features a displacement management system dubbed Active Cylinder Technology (ACT). It has become one of the main technical features in Volkswagen's lineup of engines since it was first adopted for the Polo BlueGT in 2012. The system deactivates the lifting of the second and third cylinder camshafts so that their intake and exhaust valves remain closed to stop fuel supply to the engine. This does not reduce the frictional loss of relevant parts as the reciprocal motion of the piston and connecting rod is not interrupted. However, with the valves fully shut, the compression and expansion of the air in the cylinder merely causes the air spring to elongate and contract. In this way, the ACT reduces the loss of energy used in the four engine strokes (intake, compression, expansion, exhaust), and this creates nearly the same fuel-saving effect as reducing piston displacement.

  The photo to the upper-left shows the intake camshaft (top) and the exhaust camshaft (bottom) fitted to the cam carrier which is integrated with the cylinder head cover. The exhaust camshaft is shown without the cam cap. Two cams for the second and third cylinders are installed coaxially and are switched to activate or deactivate the corresponding intake and exhaust valves.

  The photo on the upper-right shows an enlarged image of the cams of the exhaust camshafts for the second and third cylinders. Each of these have a circular cam next to a triangular cam. The two cams are made to slide along the camshaft to activate and deactivate the corresponding valves. The triangular cam opens and closes normally, but the circular cam does not have a valve-lifting lobe and the valves always remain closed. The black plastic part seen next to the cam is the mechanism used to cause the axial slide movement of the cam.

  The photo to the lower-right shows the mechanism for cam axial slide movement. Actuators for switching over the two cams are located at the top of the camshaft. A pin fitted in each actuator is pushed into the black plastic groove in the upper-right photo. This causes the camshaft to slide axially and select the cam appropriate to the situation as shown in the photos on the lower-left.

Displacement management
system
Displacement management system (ACT): Camshaft slides to switch between the two cams
Source: VW
Displacement management
system
Displacement management system (ACT)
Source: Audi
A black plastic groove for
sliding the camshaft
A black plastic groove for sliding the camshaft is seen in a hole at the top of the cylinder head cover for the actuator movement.
Camshaft slide actuators
Camshaft slide actuators located at the top of the cylinder head cover
Camshaft slide actuator
Camshaft slide actuator for the displacement management system (ACT)


Variable valve timing mechanism

Variable valve timing
mechanism
Variable valve timing mechanism (left: exhaust camshaft, right: intake camshaft)
Variable valve timing
mechanism
Variable valve timing mechanism at the front of the engine (on the right side of the vehicle when installed)


  The engine has a phase angle adjuster for both the intake and exhaust camshafts. The cylindrical camshaft phase angle adjuster is fitted inside the toothed belt-driven sprocket and can alter the inner camshaft angle relative to the angle of the outer sprocket. Pressure is regulated in two hydraulic chambers inside the adjuster, and these operate the device so it changes the inner and outer camshaft angles. The hydraulic pressure itself is controlled by a hydraulic solenoid valve that is at the top of the cam carrier-integrated cylinder head cover.

Hydraulic solenoid valves
Hydraulic solenoid valves at the cylinder head cover top
Hydraulic solenoid valve
Hydraulic solenoid valve


Exhaust manifold-integrated cylinder head

Cylinder head top
Cylinder head top (with valves and rocker arms in place)
Cylinder head bottom and
exhaust ports
Cylinder head bottom and exhaust ports


  The photo to the upper-left shows the top of the cylinder head with the intake and exhaust valves, as well as the rocker arms (roller rockers) attached. The cam carrier-integrated cylinder head cover that the camshafts mentioned above are connected with is fitted to the top of the cylinder head. The photo to the upper-right shows the bottom of the cylinder head. The exhaust ports are bundled into one at the exit, which reduces the required exhaust manifold part count. The turbocharger is mounted directly to the exhaust exit in the photo. The lower part count and insulation of exhaust gas heat before it is sent to the turbocharger helps to reduce energy loss and the need for thermal protection of adjacent parts. The Passat has a conventional pent-roof type combustion chamber with the fuel injection nozzle from the direct injection injector opening at the center along the periphery of the intake valve. As many as five cylinder head gaskets are used, presumably to absorb any dimensional change caused by thermal contraction due to differences in temperature between the cylinder block and cylinder head.

Pent-roof type combustion
chamber
Pent-roof type combustion chamber
Five cylinder head
gaskets
Five cylinder head gaskets


Water pump for engine coolant

Water pump
Water pump
Water pump as fitted to
the cylinder head
Water pump as fitted to the cylinder head


  Water pumps are generally fitted to the cylinder block, but the water pump on the Passat's engine is fitted to the back (facing the transmission). This design may have been chosen to drive the pump pulley from the camshaft at twice the speed of the crankshaft, as this increases the vane speed and also makes it possible to reduce its. The pump-drive pulley is located behind the pump vane (in the photo to the left) and is belt-driven by the pulley on the camshaft (in the photo to the right). Judging from its layout when assembled, the water pump is positioned above the transmission in a space where room can be made for other parts.

Cylinder head mounting
surface of the water pump
Cylinder head mounting surface of the water pump showing the camshaft-driven pulley, and coolant inlet and outlet ports
Water pump mounting
surface of the cylinder head
Water pump mounting surface of the cylinder head


High-rigidity cylinder block

Cylinder block
Cylinder block
Cylinder block top
Cylinder block top


  The cylinder block is a die-cast aluminum Siamese type. The black plastic part in the photo on the left is the blow-by gas oil separator.

Oil baffle plate under the
cylinder block
Oil baffle plate under the cylinder block
Cylinder block bottom
Cylinder block bottom with crankshafts, bearing caps and connecting rods in place
Cylinder block top
Cylinder block top
Crankcase side of the
cylinder block
Crankcase side of the cylinder block


High-rigidity oil pan for reducing overall engine vibrations

Cylinder block mounting
surface of the oil pan
Cylinder block mounting surface of the oil pan
Oil pan bottom
Oil pan bottom


  The die-cast aluminum pan has an extremely rigid structure. Efforts are being made to increase the rigidity of aluminum die-castings, but no other aluminum pans for mass-market vehicles are as thoroughly ribbed as the one used for the Passat. Volkswagen's intention is to increase rigidity, which thereby resists vibrations around the cylinder block and crankshafts, and reduces vibrational resonance and noises. A balance shaft is often used to offset vibrations in four-cylinder engines, but this is not the case with the Passat. Although the thinking and approach may be entirely different, increasing the engine's rigidity must have required the same cost and weight as using a balance shaft.

  The photo to the lower-left shows the joining surface for the transmission (DCT). The joining surface bulges downward to match the shape of the oil pan. The photo to the lower-right shows the engine joined with the transmission (DCT). Rigidity is increased not only in the joining surface but also along the entire length of the engine to reduce vibration of the two units. The integration of the oil pan and the cylinder block increases the joined rigidity of the two units, as well as the rigidity of the unit as a whole. One of the reasons for the nearly vibration-free ride of Volkswagen or Audi models powered by this engine may be persistent effort on the part of the engineers to increase the rigidity of the oil pan and other engine components.

Transmission joining
surface with the engine
Transmission joining surface with the engine
Engine joined with the
transmission (DCT)
Engine joined with the transmission (DCT)
Oil pump fitted to the oil
pan bottom
Oil pump fitted to the oil pan bottom
Oil pump
Oil pump


  The oil pump is fitted to the bottom of the die-cast aluminum oil pan. It is chain-driven by the front-most sprocket (located opposite from the transmission) inside the crankcase. A steel sheet oil pan undercover is fitted to the oil pan. Since the oil pan undercover is the lowest part of the engine assembly, in the unlikely event that the plastic undercover is cracked, the steel panel deforms when stones or unforeseen hard objects collide with it to limit damage to the structure of the die-cast aluminum pan above it as much as possible. An oil level sensor (manufactured by HELLA) is located in the oil pan undercover.

Top of the steel sheet oil
pan undercover
Top of the steel sheet oil pan undercover
Bottom of the steel sheet
oil pan undercover
Bottom of the steel sheet oil pan undercover


Dual-mass flywheel

Dual-mass flywheel as
installed in the engine
Dual-mass flywheel as installed in the engine
Dual-mass flywheel
Dual-mass flywheel


  This engine tends to emit rattling sounds when it is running with two cylinders deactivated, or the multiple gears of the dual-clutch transmission (DCT) are idling or under other low-load conditions. A large-diameter dual-mass flywheel is used to offset this problem.



Main powertrain parts

Piston, connecting rod Piston, connecting rod
Piston, connecting rod


  Pistons, connecting rods, crankshafts, and bearing caps with conventional designs are used in the Passat.

Crankshaft
Crankshaft
Bearing caps
Bearing caps


Air cleaner, air duct

Air cleaner exterior
Air cleaner exterior
Air cleaner interior
Air cleaner interior

  The air cleaner is located above the engine to minimize the ducting distance from the fresh air inlet at the upper edge of the front-end module to the air cleaner and turbocharger. The air duct is fitted with a resonator designed to reduce intake air sound at specific frequencies. The air cleaner is manufactured by MANN+HUMMEL and all plastic parts, including ducting, are made of PP-TD20.

Air duct
Air duct (air cleaner to turbocharger)
Fresh air duct
Fresh air duct


Engine auxiliary components and electrical components

Blow-by gas oil separator
Blow-by gas oil separator
Blow-by gas oil separator
Blow-by gas oil separator mounting surface of the engine block

  The blow-by gas oil separator is mounted to the side of the cylinder block (on the front of the vehicle). It is manufactured by MANN+HUMMEL and made of PA6.6/6 MN25 GF15. The water-cooled oil cooler is mounted above the blow-by gas oil separator.

Water-cooled oil cooler
Water-cooled oil cooler
Water-cooled oil cooler
Water-cooled oil cooler as installed in the engine

  Nearly all electrical components associated with the engine, including the engine ECU, are manufactured by Bosch. The ignition coil is manufactured by ELDOR. A negative pressure pump (manufactured by HELLA) is used for purposes including brake boosters and the turbocharged engine.

Engine ECU
Engine ECU (manufactured by Bosch)
Ignition coil
Ignition coil (manufactured by ELDOR)
Alternator
Alternator (manufactured by Bosch)
Starter motor
Starter motor (manufactured by Bosch)
Intake pipe air
temperature sensor
Intake pipe air temperature sensor (manufactured by Bosch)
Negative pressure pump
Negative pressure pump (manufactured by HELLA)


Exhaust system

Catalytic converter with a
front tube
Catalytic converter with a front tube
 Center mufflers (2) and
rear muffler
Center mufflers (2) and rear muffler

  The No.1 catalytic converter is located directly behind the turbocharger outlet. An O2 sensor (manufactured by NGK Spark Plug) is mounted to both the inlet and outlet of the No.1 catalytic converter.

  The pre-muffler is a general-purpose part, while the center and rear mufflers are stamped to different dimensions. Most Japanese automakers use general-purpose mufflers with uniform sections that are circular or ellipsoidal and an internal structure adapted for specific models. In contrast, most European automakers use mufflers that are manufactured using original dies. Stamped mufflers are more costly as they require dies, but are sometimes preferred since the muffler volume can be made as large as required. This makes it easier to achieve exhaust loss and a silencing effect at the same time as acoustic tuning. European automakers, particularly Volkswagen, have a small number of vehicle families resulting in a large production quantity per model. This leads to low die cost per vehicle, which justifies the relatively high cost for mufflers.

  The No.1 and No.2 catalytic converter parts are supplied by multiple manufacturers including Volkswagen (containers), CORNING (carriers) and UMICORE (precious metals). The pre-muffler, center mufflers, and rear mufflers are manufactured by TENNECO.

O2 sensor in front of No.1
catalytic converter
O2 sensor in front of No.1 catalytic converter (manufactured by NGK Spark Plug)
No.1 catalytic converter
No.1 catalytic converter (Containers manufactured by VW, carriers by CORNING, precious metals by UMICORE)

No.2 catalytic converter
No.2 catalytic converter (Containers manufactured by VW, carriers by CORNING, precious metals by UMICORE)

Pre-muffler
Pre-muffler (manufactured by TENNECO)
Center muffler
Center muffler (manufactured by TENNECO)
Rear muffler
Rear muffler (manufactured by TENNECO)

 

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Keyword: VW, Passat, MQB, teardown, Displacement management system, Water-cooled intercooler

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