VW Tiguan Teardown: 1.4L TSI engine
Modular structures for drive systems and cylinder blocks
In February 2019, a teardown investigation of the VW Tiguan was conducted by the Hiroshima Industrial Promotion Organization as one of its benchmarking activities. The Tiguan is VW’s crossover SUV, the sales of which are expanding against the backdrop of the increasing popularity of SUVs worldwide. Sales of the current model rapidly increased, especially in Europe in 2016 and in the North Americas and China markets in 2017. In 2018 the global sales of the Tiguan were up by 10.8% from the previous year to 770,000 units,180,000 units of which were sold in Europe, 103,000 units in the U.S. and 303,000 units in China (based on MarkLines’ sales volume by model data).
VW developed the new EA211 engine family in line with the introduction of its new MQB (Modular Transverse Matrix) platform strategy. This engine family is comprised of 3 engines with displacements of 1.0L, 1.2L, and 1.4L engines respectively, which are adopted for a wide variety of vehicle models from the A to C class segments.
The Tiguan model used for this benchmarking activity is also based on the MQB platform, equipped with the 1.4L TSI engine from the EA211 engine family. Although this engine has basically the same specifications as the engines mass produced since the introduction of MQB in 2012, it maintains its market competitiveness. In this report, an overview of the major features and main structures of the engine will be presented.
|VW Tiguan teardown|
The EA211 engine plays a key role in the realization of the objectives of the MQB platform strategy. The engine achieves modularization of advanced technologies to maintain long-term marketability, and modularization of structures to increase the efficiency of product development and production processes. This report focuses on the modular components of the engine.
In addition to this report, details of each components of the same engine are introduced in the reports listed below.
Volkswagen Passat teardown (1) 1.4L turbo-gasoline engine (October 2016)
This report introduces the overviews of the distinctive engine packaging, main engine specifications, the various technologies adopted, and the principal structural parts of the 1.4L TSI engine.
Regarding the packaging of this engine, the engine is now mounted with the exhaust side facing backwards and tilted at an angle of 12 degrees. Also, the mounting position of the engine and transmission share the same modular construction as that of the other engines. As a result, in addition to the Tiguan, the modular design is also adopted on the Golf and Passat models.
As for the main engine specifications, the base engine is a long stroke (with a stroke/bore ratio of 1.07) design with a compression ratio of 10 to improve the engine’s thermal efficiency. An intercooler turbocharger is equipped to improve the output power, realizing a power (110kW) output equivalent to that of a 2L displacement engine and a torque (250Nm) equivalent to that of a 2.5L engine. Fuel specifications require the use of unleaded premium gasoline (RON95).
Main specifications of the 1.4L TSI engine
|Modular structure of the 1.4L TSI engine|
Various technologies were introduced into the engine design such as TSI (Turbocharged Stratified Injection), and technologies to reduce pumping losses and mechanical friction.
TSI technology allows an engine to be downsized by the combination of direct fuel injection, an intercooled turbocharger, and Dual VVT. The engine realizes high knock performance and a high compression (CR=10) while having a turbocharged configuration.
The technology used to reduce pumping loss is based on active cylinder management to control the engine to operate on 2 cylinders under city driving conditions, with relatively low engine load as well during idling stop-start.
Reduction of friction losses are achieved with technologies such as reduction of the journal diameter of the crankshaft, weight reduction of the reciprocating system, reduction of the sliding friction of the piston skirts, rocker arms with built-in needle bearings, and the reduction of auxiliary belt tension by adopting an alternator de-coupler.
For the main engine architecture, a modular structure is adopted. The engine uses the same configuration as the other engines in the EA211 engine family to reduce cost by fully levering the effect of any synergy realized from the engine development, procurement, to final production phases.
Below are introduced the various technologies of the modular architecture of the engine.
Drive system module
The valve train and accessories are composed of 2 drive systems.
Drive system for the valve train
|Drive system of the valve train|
The valve train is of the DOHC type, with the engine adopting a Dual VVT system wherein VVT is used on both the intake and exhaust cam shafts, independently controlling the intake/exhaust valve timing. Optimization of the effective compression ratio and residual gases is achieved by controlling the overlap angles of the intake and exhaust valves and the late intake valve-closing. For camshaft timing drives, a timing belt is used rather than a chain belt to achieve weight reduction as well as realize a 30% reduction in friction losses.
Drive system module of engine ancillary components
|Drive system for ancillary components|
The alternator and the A/C compressor are attached directly to the cylinder block instead of with brackets, realizing a compact and lightweight design/structure. Also, the engine ancillary components are driven with a 6-groove ribbed V-belt. The decoupler is attached to the alternator and suppresses the impact torque due to the rotational torque fluctuations of the alternator. This design results in a 50% reduction in belt tension compared with conventional systems and is intended to reduce frictional losses.
The water pump, typically located in front of conventional engines, is mounted at the rear side of the engine which results in a simplified ancillary drive at the back of the engine.
Cylinder head cover module
|Valvetrain module and ACT (active cylinder management)|
The cylinder head cover is a modular structure with the camshaft integrated inside the cylinder head cover.
To achieve lightweighting, the camshaft is made of the cam lobe portion and the shaft portion, and for cylinders No1 and No4, the camshaft is manufactured by press-fitting both parts.
Cylinder management is realized by deactivating the No2 and No3 cylinder valves. A cam lobe for driving and a cam lobe for valve deactivation are provided on the cam and switched on or off by sliding the cam lobe on the shaft by using electromagnetic actuators.
A ball bearing is used on the camshaft axle on the pulley side to reduce friction losses. By application of these technologies, the system aims to improve fuel consumption by 10~20%.
Cylinder block module
The cylinder block module is comprised of 3 parts: the cylinder head, cylinder block and the water pump module.
To reduce friction losses, the valve train adopts the roller rocker arm design. The design of this roller rocker arm and hydraulic lash adjuster is a common design shared across automakers and is believed to be supplied by Schaeffler.
The exhaust manifold is integrated into the cylinder head. With this design, more heat is exchanged from the exhaust gas to the coolant, enabling quicker engine warm up during cold starts, which improves cabin heater performance. The design also aims to improve fuel efficiency by reducing the exhaust gas temperatures during high-speed driving. This is also one of the key technologies to resolve issues related to engine downsizing.
Combustion related parts
The combustion chamber on the cylinder head side is of the typical pent-roof type combustion chamber design. The high-pressure injector has 5 nozzle holes, positioned between the intake ports, and the fuel is injected towards the direction of intake tumble flow. To optimize the placement of the high-pressure injector, intake valves, and the ignition plug inside the combustion chamber, a mini spark plug with an outer diameter of 12mm (M12) is used.
The high-pressure injection pump is driven by the camshaft. Multiple fuel injection pulses and injection pressure are controlled according to engine operating conditions.
The combustion chamber on the piston side has a medium concave shape without any projections. The design reduces the adhesion of fuel film on the wall and reduces PM emissions, which is a problem in direct fuel injection engines.
|Piston-side combustion chamber||Piston-side combustion chamber|
|High pressure injector||High pressure injector pump|
The aluminum alloy cylinder block is molded with cast iron cylinder liners. The oil cooler mounting area and the block ventilation structure are integrated on the side of the block, and fixtures such as external piping are omitted as much as possible.
|Cylinder block||Cylinder block side face|
The engine cooling system is a two-circuit cooling system, with one coolant circuit for cylinder bore cooling and the other for combustion chamber cooling. The coolant is controlled by separate thermostats set at different temperatures, which improves engine warm-up performance.
The crankshaft is forged, with a relatively slender axle diameter and an induction-hardened bearing. Although efforts were put into lightweighting and friction reduction, rigidity of the crankshaft is low and NVH performance is considered an issue. Due to this concern, the cylinder block structure supporting the crankshaft is designed with high rigidity.
Water pump module
|Water pump module and water pump pulley|
The water pump module is comprised of the water pump and the thermostat casing. The water pump for engine cooling is mounted at the rear of the engine and is driven by a belt through the water pump pulley mounted on the exhaust camshaft. The thermostat for the two-circuit cooling of the engine is built into the casing.
Intake and turbo module
The module is comprised of the turbocharger and the intake manifold.
The turbocharger is specified as a compact single-scroll turbine and is mounted on the exhaust manifold that is integrated into the cylinder head. The control of the turbocharger wastegate is operated by an electrical actuator that has been specifically optimized for low-end torque and with improved transient response characteristics. As a result, a maximum torque of 250Nm at 1500rpm is achieved, with a response time of 2.5s to maximum torque. Furthermore, the λ＝1 operating region is expanded to the turbocharging region, thereby improving fuel economy.
|Intake manifold with built-in intercooler|
The intake manifold is made of plastic manifold with a built-in intercooler. The charged intake air from the turbocharger passes through the throttle valve, enters the intake manifold, and after being cooled by the intercooler is finally guided to the combustion chamber. The intercooler is water-cooled with a very compact construction.
Teardown, VW, Tiguan, MQB, Engine, Downsizing, Drive system, VVT, Timing System, Timing Belt, Alternator, Compressor, Cylinder Head Cover, Camshaft, Engine Valve, Cam lobe, Bearing, Cylinder deactivation, Cylinder Head, Exhaust Manifold, Fuel Injection, Fuel Pump, Spark plug, Cylinder block, Crankshaft, Engine Cooling Module, Water Pump, Water pump pulley, Thermostat, Turbocharger, Wastegate, Air Intake System, Intake Manifold, Inter Cooler, Throttle valve
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