21/10/12

Overview: Volkswagen Golf

The all-new Volkswagen Golf has been unveiled in Berlin, four years after the current model débuted and 36 years after the original model more or less redefined the small family car in the early years of the hatchback. Over 29 million Golfs have been sold.

Despite offering more room for passengers and more on-board technology, new production techniques contribute to the Mk VII Golf being up to 100kg lighter than the car it replaces. The new Golf is also safer, thanks not just to a stronger body structure (which is also 23kg lighter) but also to the usual raft of standard and optional passive and active safety systems which are available off-the-shelf from electronics giants like Bosch and Hella.

The new Golf is built on the so-called MQB (Modularer Querbaukasten) platform or Modular Transverse Matrix. This standardises many vehicle component parameters across brands and vehicle classes, and allows access to new powertrains and technologies, including innovations in the areas of safety and infotainment.

At 4255mm long, the new Golf is 56mm longer than its predecessor, with a 59mm longer wheelbase of 2637mm. The front wheels are 43 mm further forward, helping to generate more interior space, while the new Golf is also 13mm wider, at 1799mm, and 28 mmlower, at 1452mm. This helps to create a 10 per cent improvement in the drag co-efficient; in the case of the Blue Motion model, this is now 0.27 Cd.

Inside the Golf there is more room than previously. Rear legroom is improved by 15mm, and the front seats have been moved 20mm further back, benefitting taller drivers. Front shoulder room is improved by 31mm to 1420mm — at the rear it is 30mm wider — and elbow room increases by 22mm to 1469mm — there is 20mm more in the rear. There is more room for luggage, too: the boot is 30 litres larger, at 380 litres, with a sill height of 685mm. The front passenger seat can also optionally fold fully forward, creating a loadspace which is up to 2412mm long.

In the cockpit, the centre console is now angled more towards the driver, giving them easier, more ergonomic and direct access to auxiliary controls, including the new generation of touchscreen infotainment systems that is available on the Golf. All Golf models now have touchscreen systems as standard, starting in the U.K. with a 15cm colour display system, and rising to the range-topping satellite navigation system with 20cm colour display. It operates with finger gestures that will be familiar to smartphone users. Features include DAB digital radio, auxiliary inputs (including USB), Bluetooth telephone preparation and access to vehicle trip information.

Between the front seats, space is increased by virtue of the new electronic parking brake; this has an auto-hold feature. The compartment under the centre armrest optionally includes a universal phone holder with inductive aerial, which not only increases the signal strength of a phone placed in it, but also reduces the drain on the phone’s battery.

The new Golf also features a number of new standard safety systems, while optional systems include many previously only available on vehicles in a class above.

Standard on all new Golf models is a multi-collision brake system. This automatically brakes the vehicle after a collision, to reduce kinetic energy significantly and thus minimise the chance of a second impact. Research in Germany shows that around a quarter of accidents involving personal injury are multi-collision events. Also standard from SE trim upwards is the PreCrash system that made its debut on the Touareg. If it detects the possibility of an accident, it pre-tensions seatbelts and closes the windows and sunroof, leaving just a small gap, to ensure the best protection from the airbags.

Other electronic aids include Adaptive Cruise Control (standard in the U.K. from SE models upwards), which uses radar sensors to maintain a set distance from the vehicle in front; Front Assist, which can bring the vehicle to a complete stop and operates at speeds of up to 150km/h (93mph); and City Emergency Braking, which operates at up to 30km/h (19 mph), and can reduce or prevent the chance of accidents occurring. A Driver Alert System, as introduced on the Passat, monitors the driver’s inputs, to detect any signs of tiredness; while a camera-operated Lane Assist system can help keep the car in a specific lane, providing countersteering assistance where necessary. A Dynamic Light Assist system optionally masks the vehicle’s high beam lighting, making for good illumination without dazzling on-coming traffic.

The Golf’s steering now uses a variable ratio system that offers more agile steering in dynamic driving situations, while ensuring high-speed stability, and easy manoeuvring in town: the steering becomes higher-geared as lock is applied. Specify the latest generation Park Assist, and the new Golf will park itself in a space no more than 80cm longer than the vehicle.

For the first time, the Golf is also available with driver profile selection, which allows the driver to choose from four modes — Eco, Sport, Normal and Individual; if a DSG gearbox is fitted, a fifth option — Comfort — is also offered. Each of these modes alters the throttle mapping and engine management (among other parameters) to the chosen style, so in Eco mode, for example, the engine management, air conditioning and ancillary systems are controlled to achieve maximum fuel efficiency.

Powering the Golf is a new range of petrol and diesel engines, all of which incorporate stop-start and kinetic energy regeneration systems, charging the battery on the overrun. At launch, the petrol engines are a 1.2-litre TSI 85PS unit returning 4.9l/100km (around 57.6mpg and 113g/km), and a 1.4-litre TSI 140PS unit with Active Cylinder Technology, which can deactivate two of the cylinders, and achieves up to 4.8l/100km (58.9mpg and 112g/km). The launch diesel engines are a 1.6-litre unit with 105PS, which returns 3.8l/100km (74.3mpg and 99g/km), and a 2.0-litre 150PS unit which returns 4.1l/100km (68.9mpg and 106g/km).

In detail

Volkswagen stresses the efforts that have been made to reduce the kerb mass of the car. The result is that up to 100kg has been saved, model-for-model. The body-in-white weighs 23kg less.

If you divide the car up into the primary areas of electrical, engines, running-gear and superstructure, weight savings (depending on model) are as follows:

  • Up to 6.0kg — Electrical
  • Up to 26.0kg — Running-gear
  • Up to 37.0kg — Superstructure
  • Up to 40.0kg — Engines

In pure arithmetic, the total potential saving is thus even as much as 109kg, though in practice the limit is 100kg for a ‘real’ car with a standard specification.

The greatest weight reduction is achieved from the engines and superstructure. It is particularly interesting to look into the details of the superstructure (car body and interior) and the 37kg saved here, as it shows how lightweight design that is compatible with large-scale production can be achieved in 2012.

  • 0.4kg — Dashboard (20 per cent. lighter)
  • 1.4kg — Module cross-member (beneath dashboard)
  • 2.7kg — Air conditioning
  • 7.0kg — Front and rear seats (depending on version)
  • 23.0kg — Body
  • 2.5kg — Miscellaneous

Volkswagen made the dashboard 20 per cent. lighter thanks to a new thermoplastic foam injection process — the load-bearing, sandwich-like structure beneath the surface consists of this material. At the same time, this component is 20 per cent. more rigid.

Mounted on the module cross-member are both the steering gear and the dashboard. Altogether the cross-member weighs 5.8kg. The reduction in weight was achieved with a lightweight design approach using finite element analysis for the steel components, dealing with wall thicknesses and structural design measures, such as corrugations.

Using methods such as finite element analysis, Volkswagen is emulating structures found in nature, where the natural world is able to attain a high strength-to-mass ratio.

The Golf’s entire air conditioning system has been redesigned and, as noted, is 2.7kg lighter. They also run very quietly (up to 5dB(A) lower), they reach the desired temperature significantly faster and are very energy-efficient — up to 4A less — which is down to the use of a new type of blower control with ‘intelligent climate control’. The 2.7kg weight reduction is achieved by such design modifications as reducing wall thicknesses of various system components, reducing the diameters of pressure lines, a new fastening system and a light heat-exchanger.

The seating system is also new. Along with numerous minor modifications to the seats, mass was reduced, especially in the rear backrests, to save a total of up to 7kg. Once again, the finite element method and high-strength steels combined with laser welding made it possible to reduce wall thicknesses and tweak profile geometries. Engineers achieved weight savings of over 15 per cent. in this way, and by using lighter backrest latch mechanisms.

The passenger cell of the body must obviously be strong to achieve the best possible safety and comfort. Torsional rigidity is important for handling, while light weight determines fuel consumption. Making a structure strong, light and affordable is harder in the mass-market where exotic alloys would be too expenive. Expensive materials like aluminium, magnesium or carbon-fibre are more or less out of the question for bodyshells in this segment. Volkswagen relies on what it calls the ‘Modular Transverse Matrix’ (MQB in German), the use of high-strength steels and advanced production methods. This approach yields a 23kg reduction in mass of the car body structure without additional costs, while satisfying more stringent crash and rigidity requirements, and with a slightly larger structure.

Of the 23kg that has been saved:

  • a 12kg saving derives from the use of high-strength and advanced high-strength steel grades and the reduction of sheet metal thickness;
  • 4kg is saved by only using materials where they are needed; and
  • 7kg is saved by optimising profile and surface geometries.

The share of high-strength steels has grown from 66 per cent. to 80 per cent. compared to the Golf Mk. 6. Volkswagen has built up its understanding of ultra-high-strength, hot-formed parts since the Golf Mk. 6 and has invested in its manufacturing facilities. The share of these parts, which are up to six times as strong as conventional steel parts, has grown from six per cent in the Golf Mk. 6 to 28 per cent. in the new Golf. Also, new advanced high-strength steels are available on the market today that did not exist when the previous model was being developed. These represent another nine per cent of the new Golf’s bodyshell. The advantage of these extremely strong steels is that the finished parts made of them can be designed to be considerably thinner than before and still handle the stresses of a crash. Nearly the entire safety architecture of the new Golf consists of these steels. Hot-forming saves a total of 12kg in mass.

The second lightweight design strategy — to use material only where it is needed — is an obvious one. Efforts include varying the sheet metal thickness within a part; this is done at the rolling mill of the steel supplier, which delivers a tailored blank — a rolled blank with variable thickness — to the hot-forming facility. One advantage compared to conventional tailored blanks is that eleven zones can be produced within a cross-member, each with tailored sheet thickness. The transitions between the different sheet thicknesses are uniform here and do not exhibit any abrupt changes in strength. The savings for just these parts is 4kg.

Geometries of the load-bearing structure and surface parts have been optimised for many years. Continually improved virtual methods in the development process can be used to use existing installation spaces more effectively. Take the example of the longitudinal frame member. Making better use of the mounting space between the engine and the front of the chassis has allowed a 25 per cent. increase in profile cross-section, which in turn enabled the use of thinner stock. Nonetheless, the entire front structure of the new Golf can absorb more energy in a frontal crash, thanks to geometry that is developed using finite element analysis. In the case of surface parts such as the bulkhead and the floor, acoustically effective corrugation patterns were introduced that also make the sheet metal more rigid and in turn lead to a reduction in the need for sound insulating material. These examples result in a mass reduction of 7kg.

Welding processes and innovative tools make a contribution towards the quality of the bodyshell. Some new techniques are making their début in the new Golf. These include the laser clamp welder: this tool enables what are referred to as wobble welds, which are able to produce the joint between parts on a short flange. The ‘wobble’ is the sinusoidal path of the laser weld seam.

Hot-formed parts have an extremely high tensile yield strength of 1000MPa. This is over six times the strength of conventional deep-drawn steels and up to four times the strength of conventional high-strength steels. In the hot-forming process, a red-hot blank, heated to approximately 950°C, is inserted in the forming tool, formed in a work process and then quickly cooled in the tool. Excellent material properties can be realised.

We always found the sixth generation Golf to be a very civilised car, and Volkswagen claims to have equalled its refinement in the new model. Interestingly, no actual improvement is claimed. Simulation tools were employed to evaluate component layouts with regard to their comfort and acoustics early on. This type of evaluation analyses parameters such as vibrations and sound pressure, which are perceived directly by the driver and passengers in the car. As a result, it was possible to maintain the level of acoustic comfort of the previous model to the new Golf, despite the weight savings.

Engine mounts are critical in controlling the transmission of noise from the power unit and gearbox. For the new Golf, the mount elements were completely redesigned, while retaining the pivot bearing concept. Despite reductions in component masses, the performance of the engine mounting system has been improved. Along with reducing the amount of structure-borne noise from the driveline, improvements were made in vibration damping by optimising the geometries of the engine and gearbox mounts. The new engine mount system for the Golf results in smaller movements of the engine assembly.

Clearly, acoustic considerations are part of engine development. In the case of the TDI units, this included measures for acoustic integration of the oxidation catalytic converter, the charge air tube, oil sump and dampers on the firewall side of the crankcase. In addition, partially encapsulating the engine compartment in a sound-absorbent material reduces noise transmission.

The good aerodynamics of the new Golf mean that wind noise is reduced at source, though good sealing is still needed. Volkswagen describes the sealing of the Golf body as ‘elaborate’. However, reducing engine and road noise raises the risk of other sounds becoming more audible — for example, the fan motor, toothed belts or the turbocharger. Volkswagen claims to have reduced or eliminated such background noises at their sources, largely avoiding the need for additional, secondary acoustic measures in these areas.

Just as in the sixth generation Golf, an acoustically effective damping film is used in the windscreen of the new model. This film particularly reduces noise in the frequency range from 2.5kHz to 3.5kHz. In addition, the use of absorbers in the front doors and a new design of door seals has achieved a further reduction in the amount of environmental noise that finds its way into the interior.

Infotainment systems

The new Golf has the first Volkswagen touchscreen with a proximity sensor — the display automatically switches to operating mode as a hand approaches. There are three display sizes — 13cm, 17cm and 20cm. Navigation updates for three years are included.

All systems have a touchscreen as standard. The new device generation is available in six extension levels and in three different display sizes, as we have mentioned. For the first time, Volkswagen is implementing displays that, with the exception of the smallest screen, have proximity sensors: as soon as the driver or front passenger moves a finger near to the touchscreen, the system automatically switches from display mode to input mode. Display mode shows a screen that is reduced to just the essentials. In operating mode, the elements that can be activated by touch are highlighted. The displays also have a function that lets users scroll through lists or browse CD covers in the media library with a wipe of the hand. In designing the new generation of devices, the primary goal was to integrate the most advanced infotainment applications into the car, which should be consistently easy to use despite all of the complexity of today’s systems — that is, they should be totally intuitive and therefore safe to use while driving.

Basic touchscreen — trip computer and interface; standard display (13cm). The standard display in the new Golf is a 5-inch black-and-white unit. The functional scope of the production module includes trip computer information, clock time and date, service menu (oil change status and so on), vehicle settings (e.g., winter tyre warning), adjustment of instrument lighting, language setting, climate control menu, Eco-HMI displays (information on power consumers and tips for an especially economical style of driving) and — depending on the car — steering wheel heating, the visual display for the Park Pilot, and driving profile selection.

Radio systems — proximity sensor starting with 17cm screen. The next level system specification comes as standard starting with the Comfortline model in countries such as Germany and is otherwise available as an option. There are three buttons to the left and three to the right of the touchscreen that are used to activate the ‘Radio’, ‘Media’, ‘Car’, ‘Setup’, ‘Sound’ and ‘Mute’. It also offers a SD card slot, aux-in interface and two push dials (for on/off, volume, mute). This standard module also includes an FM/AM radio, with loudspeakers in the front of the car.

The ‘Composition Colour’ radio has a 13cm display. Similar to the Composition Touch in its device layout, the Composition Colour is also equipped with such features as a colour display, FM/AM radio as well as front and rear loudspeakers and a CD drive (MP3 compatible). The CD drive is located in the glovebox along with the SD card slot.

The ‘Composition Media’ radio has a 17cm screen with a proximity sensor that is integrated across the area beneath the display. The display responds to wiping and zooming gestures, used in similar fashion on modern smart phones. There are now also four buttons to the left and four to the right of the touchscreen; in contrast to the 13cm systems they also enable access — depending on the car — to the ‘Phone’ and ’Voice’ (voice control) menus. The USB and aux-in interfaces are integrated in a separate compartment on the centre console in front of the gear lever; this compartment also offers storage space for a smart phone.

‘Discover Media’ navigation function (13cm): The Composition Media radio can have a navigation module (Discover Media) added to it. The features and functions are identical except for the navigation system that is integrated with European map data and the associated second SD card slot; the navigation computer is located in the glovebox together with the CD player and SD card slot. The price for all units with a navigation module includes updates of the European navigation maps for three years.

‘Discover Pro’ radio-navigation system (20cm): The top radio-navigation system with a large 20cm capacitive touchscreen is known as the Discover Pro. Features installed here — beyond those of the Discover Media — are a DVD drive (audio and video) instead of a CD drive, extended premium voice control (base version is available as an option for Composition Media and Discover Media), 3D navigation and a 64GB flash memory; a UMTS telephone module is available as an option. Integration of the Compact Disc Database from Gracenote also enables playback and management of media. In addition, the Discover Pro also operates as a WLAN hotspot for Internet access with WLAN-capable mobile devices (a smart phone or tablet).

Innovations & high-tech features

The new Golf is the first Volkswagen with a multi-collision brake system. This system, which is standard, reduces the severity of secondary collisions by applying the brakes if the car is shunted.

Volkswagen’s XDS transverse electronic differential lock is standard. This is the system used on the previous generation of Golf GTI. Adaptive cruise control includes Front Assist and the City Emergency Braking function. Other assistance systems include the Lane Assist lane-keeping assistant, fatigue detection, traffic sign detection, and the latest generation of the Park Assist system, including warning for obstacles in the vehicle’s surroundings, with a 360-degree display. The automated light functions Light Assist and Dynamic Light Assist are also available. Other new technologies include progressive steering, a driving profile selector with up to five modes (‘Eco’, ‘Sport’, ‘Normal’, ‘Individual’ and, in combination with DCC, ‘Comfort’), an electronic parking brake, a newly developed ergonomic sport seat (called Ergo-Active), a guard against using the wrong fuel in the diesels, a new deluxe climate windscreen that is also a first in this segment, and a new generation of information and entertainment systems.

The Golf’s multi-collision brake system has already won a safety innovation award from Germany’s largest automobile club, the ADAC. Accident research has found that approximately a quarter of all traffic accidents involving personal injury are multiple-collision accidents — that’s to say, there is a second impact after the initial collision. The multi-collision brake system automatically brakes the vehicle when it is involved in an accident in order to stop it or, at least, slow it. Triggering of the multi-collision brake system is based on detection of a primary collision by the airbag sensors. Vehicle braking by means of the multi-collision brake system is limited by the ESC control unit to a maximum deceleration rate of 0.6g. This value matches the deceleration level of Front Assist; it ensures that the driver can take over handling of the car even in case of automatic braking. The driver can ‘override’ the multi-collision brake system at any time; for example, if the system recognises that the driver is accelerating, it is switched off. The automatic system is also deactivated if the driver initiates hard braking at an even higher rate of deceleration. Essentially, the multi-collision brake system applies the brakes until a vehicle speed of 10km/h is reached; it is then switched out.

The proactive occupant protection system is a typical example of a technology that is being transferred from the premium class to the compact class. Volkswagen first implemented the proactive occupant protection system in the Touareg. Now the system is making its début in the Golf. If the system detects a potential accident — for example, by the initiation of hard braking by the brake assistant — the seatbelts of the driver and front passenger are automatically pre-tensioned. When a highly critical and unstable driving situation is detected — such as severe oversteer or understeer with ESC intervention — the side windows and sunroof are closed, leaving a small gap in the windows. That is because the head and side airbags offer their best support with windows and sunroof almost fully closed.

Until now, adaptive cruise control (ACC) was reserved for vehicles in higher segments. Now ACC has arrived in the compact class with the Golf, and is being offered at a relatively low price of €555 (in Germany). The system uses a radar sensor integrated into the front of the car. ACC operates over a speed range from 30km/h to 160km/h and is available with both manual and dual clutch gearboxes. In vehicles with DSG, adaptive cruise control intervenes to such an extent that the car may be slowed to a standstill, depending on the situation. In combination with Lane Assist, it may also automatically pull away in stop-and-go traffic. ACC maintains a preselected speed and a defined distance to the vehicle ahead, and it automatically brakes or accelerates in flowing traffic. The system dynamics can by individually varied by selecting one of the driving programs from the driver profile selector available as an option.

Front Assist is a surroundings monitoring system. It works like ACC with the radar sensor integrated into the front of the car, which continually monitors the distance to the traffic ahead. Even with ACC switched off, Front Assist helps the driver in critical situations by priming the brake system and alerting the driver to any required reactions by means of visual and audible warnings. If the driver fails to brake hard enough, the system automatically generates sufficient braking force to avoid a collision. Should the driver not react at all, Front Assist automatically slows the car so that under ideal conditions the speed of any impact is minimised. The system also assists the driver by an alert if the car is getting too close to the vehicle in front.

The new City Emergency Braking function is part of Front Assist. It scans the area in front of the car using a radar sensor. The new system operates at speeds below 30km/h. If the car is in danger of collision with a vehicle driving or parked up ahead and the driver does not react, the brake system gets primed in the same way as with Front Assist. If necessary, City Emergency Braking then automatically initiates hard braking to reduce the severity of the impact. In addition, if the driver fails to press the brake pedal sufficiently, the system will assist with maximum braking power.

Fatigue detection was first introduced in the current Passat. It detects waning driver concentration and warns the driver with an acoustic signal lasting five seconds. A visual message also appears on the instrument cluster recommending taking a break from driving. If the driver does not take a break within the next 15 minutes, the warning is repeated once. At the beginning of each trip, the system analyses a range of factors, including the driver’s characteristic steering behaviour. Once under way, the fatigue detection system continually evaluates signals such as steering angle. If monitored parameters indicate a deviation from the steering behaviour recorded at the beginning of the trip, the visual and acoustic warnings are delivered.

Lane Assist: In the Golf, this camera-based lane-keeping assistant with steering intervention operates with extended functionality: adaptive lane tracking. If desired, the system can now also maintain continuous tracking support. In addition, where necessary Lane Assist will correct the driver’s steering: as soon as it becomes evident that the driver is leaving the driving lane or is driving over the lane markings without setting the direction indicator, the system gently steers the other way.

Progressive steering: This is Volkswagenese for variable ratio steering, in which the ratio becomes progressively higher as lock is applied. The system is optional. The rack has variable tooth spacing and the system uses a more powerful electric motor.

XDS is a feature originally developed for the Golf GTI. It is an electronic differential lock, now standard in every Golf. It improves both traction and handling. Technically, XDS is a functional extension of the EDS electronic differential lock that was integrated in the ESP system. In fast cornering, as soon as the electronics detects slip at the wheel of the driven front axle located at the inside of the bend, the ESP hydraulics build up pressure specifically at this wheel to restore traction. As a differential lock, XDS compensates for the understeer in quick cornering that is typical of front-wheel drive vehicles.

Volkswagen Golf Mk. I and Mk. VII (to scale).

Electric parking brake: Familiar elsewhere. Instead of a handbrake lever, a control switch plus an Auto Hold switch are located on the centre console. The electric parking brake offers some advantages: eliminating the conventional handbrake frees up more space on the centre console; in addition, the brake is automatically released when driving off, making hill starts easier. The Auto Hold function prevents unintentional rolling from a standstill position.

Dynamic Light Assist — dynamic main beam control: Using a camera mounted behind the windscreen, the system analyses the traffic ahead and the oncoming traffic. Based on this data, the main beam automatically comes on at speeds of over 60km/h and stays on unless main beam would cause dazzle to another driver.

This is how Dynamic Light Assist works: with the help of the camera, the main beam modules of the bi-xenon headlights with dynamic cornering lights are masked only in those areas that the system has determined could potentially disturb other road users. This function is implemented by a pivoting masking aperture between the reflector with the xenon filament and the lens. Along with lateral swivelling of the entire module and independent control of the left and right headlights, this additional aperture geometry is able to mask the light source and thereby avoid dazzling traffic ahead or any oncoming traffic.

Light Assist — main beam control: For models that have headlights without cornering lights, Light Assist is available — the base version of the main beam assistant. Light Assist analyses traffic ahead and oncoming traffic using a camera behind the windscreen and automatically controls activation and deactivation of the main beam (from 60km/h).

Traffic sign detection initially made its début in the Phaeton. In the new Golf it will be available in combination with a navigation system, because the traffic signs are shown in the display of the active navigation window. If the system detects any speed limit or ‘No overtaking’ signs, up to three of these will get shown on the instrument cluster in front of the driver and on the navigation system display. This will also include all additional information and the signs will appear in a logical order: those that immediately apply (e.g., a 130km/h speed limit) get shown in first place, while signs that only apply at certain times (e.g., ‘80km/h when wet’) appear in second place. If the rain sensor registers that it is starting to rain, the traffic sign that is now most pertinent — the ‘when wet’ sign — moves up into first place.

The latest version of the Park Assist parking assistance system now facilitates not only assisted parking parallel to the carriageway, but also reverse parking at right angles to the road. In addition, Park Assist 2.0 is also equipped with a braking and parking space exit function. The system can be activated at speeds of up to 40km/h by pressing a button on the centre console. Using the indicators, the driver selects the side on which the car is to be parked. If, using the ultrasound sensors, Park Assist detects a large enough parking space (a manoeuvring distance of 40cm, front and rear, is sufficient), the assisted parking can begin: having put the vehicle into reverse, all the driver has to do is operate the accelerator and brake. The car takes care of the steering. Acoustic signals and visual information on the multifunction display assist the driver. If a collision is looming, the system can also actively apply the vehicle’s brakes.

Making its début with the new Golf is the second generation of Dynamic Chassis Control. It is the first vehicle in the Volkswagen Group in which this new system is being deployed. DCC still offers the three driving modes of ‘Comfort’, ‘Normal’ and ‘Sport’, which are now selected and displayed via the touchscreen on the centre console as part of the higher-level ‘Driving Profile Selection’ function. In the ‘Individual’ driving profile, the DCC mode can even be assigned other driving profile properties. The DCC system adaptively controls the damper valves, and thereby the setting of the damper characteristic, based on a further developed and refined Volkswagen control algorithm. DCC uses the input signals from wheel displacement sensors and accelerometers as well as vehicle information from the Chassis-CAN bus; it uses these values to compute and set the ideal damping force.

In the new Golf, the DCC chassis was lowered by 10mm compared to the normal chassis, and along with specific dampers, it also has its own spring and anti-roll tuning. For the MQB platform, the DCC system was extended to add a version with the modular lightweight suspension (for models with less than 90kW in power), which is being introduced for the first time in the new Golf. So far as the sensors are concerned, some parameters have been changed; designs of the wheel displacement sensors were adapted to the new MQB suspensions, and they were weight optimised. The body accelerometers were converted from three analogue lines to two digital lines; the DCC control unit was redesigned in its hardware configuration, components and layout. A new generation of processors operating at 180MHz gives control with one-millisecond cycles.

Volkswagen has developed an entirely new air conditioner for the seventh generation Golf. The primary objective was to reduce noise and weight while increasing efficiency. In addition, the new system would be designed to be more compact in its construction. Fluid dynamic simulation was used to modify the cross sections of internal air conditioner components to reduce net pressure losses. This progress also led to a noise level reduction of up to 5dB(A) and to a reduced need for the electric blower — thereby a gain in efficiency. In addition, the use of a pulse-width modulated blower reduced current consumption by 4A on average. An improvement in acoustics was realised compared to the previous model by specific fluid dynamic studies of the recirculation air flaps. Partially reduced wall thicknesses of the polypropylene housing, a new fastening design without complicated brackets, and the use of higher performance, lightweight heat exchangers led to significantly lower weight of the new air conditioner. The system package was improved by such measures as a new filter layout above the blower in the air intake channel; this makes the system 140mm narrower here. This enabled a uniform layout of electrical system components between left-hand drive and right-hand drive vehicles, and it created more space in the foot area. A high-performance heat exchanger as well as reduction of heat losses in the refrigerant cycle, demand-based use of electrical auxiliary heating and an innovative thermal management system has also improved heating performance. Compared to the previous model, the interior of the new Golf heats to a ‘pleasantly warm’ temperature (?) 30 per cent. faster.

In addition, the refrigerant cycle was completely redesigned for maximum efficiency gain, weight reduction and manufacturing convenience. The refrigerant cycle consists of a highly efficient compressor and condenser as well as an internal heat exchanger. Design of the refrigerant lines was also altered; one effect was a considerable weight saving. Also, along with improvements to the system design, another benefit of the efficient refrigerant cycle is that it cools the interior significantly faster.

The new Climatronic system of the Golf regulates the interior temperature automatically via two-zone temperature control — separate for driver and front passenger. The intensity of the climate control can be influenced by selecting a profile — ‘Gentle’, ‘Moderate’, ‘Intensive’. The fully automatic control unit operates with various sensors — a sun sensor, air quality sensor and new humidity sensor. The sun sensor detects the intensity and direction of solar radiation, and the system is controlled accordingly.

When information from the air quality sensor indicates that the concentration of nitrogen oxides or carbon monoxide in the outside air has exceeded a defined limit, then the recirculation flap of the Climatronic system closes. The addition of a humidity sensor offers the great advantage that for the first time it is also possible to control the heating function with recirculation mode. This results in significantly quicker heating of the interior without fogging of the windows.

The humidity sensor is also used to run the air conditioning compressor at a lower power level, as needed, reducing energy consumption. Here, the Climatronic automatically deactivates the compressor as soon as it is not needed to reach the desired temperature, or if there is no risk of window fogging and a preset limit for humidity is not exceeded in the interior. For the first time, air conditioning components that are relevant to fuel economy are then only activated as needed and controlled to reduce energy consumption in all operating modes. The interplay of all components of the new air conditioning system leads to considerable fuel savings compared to the previous model.

An optional deluxe climate windscreen is being offered for the new Golf. This new windscreen combines the advantages of conventional wire heating with those of heat-insulating glass. Wires are no longer embedded in the glass; rather, an extremely thin, electrically conductive layer is used that can be heated in the glass laminate. In cold weather, this function prevents fogging; it also accelerates defrosting. In the summer, the new windscreen results in less heating of the interior, because the extremely thin coating reflects solar radiation. Along with an increase in comfort, fuel economy also benefits, since the air conditioning does not need to supply as much cooling power.

Of passing interest is the optional panoramic tilt/slide sunroof. It offers ventilation and opening functions, does not have any effect on the torsional rigidity of the car and has the visual effect of lengthening the windscreen. The tinted, heat-insulating glass reflects 99 per cent. of U.V. radiation, 92 per cent. of incident heat radiation and 90 per cent. of incident light. Apparently, according to a study conducted by the Medical University of Siena, Italy, roof opening systems in a car contribute towards a feeling of general well-being. We would add that they contribute to a general feeling of annoyance when driving beneath a row of trees because of the flashing effect; but who are we to argue with the Medical University of Siena?

Engines

Volkswagen has developed two completely new generations of engines for the seventh generation Golf. All are turbocharged direct-injection units; all are equipped with a stop-start system (giving savings of around four per cent.) and kinetic energy regeneration, which charges the battery on the overrun (worth around three per cent.).

Two notable engines are a 1.4 TSI with 140PS and a 1.6 TDI with 110PS. The 140PS TSI is the first Golf engine to feature the optional automatic cylinder deactivation (ACT); thanks to this new technology and the reduced overall mass of the new car it consumes 4.7l/100km (equivalent to 109g/km CO2). The 110PS TDI in the new Golf BlueMotion returns a combined rolling-road fuel consumption of 3.2l/100 (85 g/km CO2). Standard manual gearboxes are five- or six-speed units, depending on the engine. Most of the TSI and TDI engines may also be combined with an automatic dual-clutch gearbox (DSG).

The new petrol engines are of the EA211 engine series. The offer 85PS, 105PS, 122PS and 140PS. The 140PS version can be ordered with the automatic cylinder deactivation, or ACT, as an option; this reduces fuel consumption by up to 0.5l/100km.

The new diesel engines are of the EA288 engine series. Outputs of 105PS, 110PS and 150PS are available.

For the first time, a driving profile selector is being offered in the Golf. Four profiles are available, or five in conjunction with dynamic chassis control: Eco, Sport, Normal and Individual; with DCC, a Comfort setting is also available. In the Eco driving profile, the engine controller, air conditioning and other auxiliary units are controlled to reduce fuel consumption. In addition, vehicles with DSG have an additional coasting function in Eco mode; when the driver releases the accelerator pedal, the DSG disengages and the engine idles. This makes good use of the car’s kinetic energy — at least, in theory. But diesel engines cut off their fueling on the overrun provided the engine speed is above idle, and petrol engines do the same at rather higher crankshaft speeds, so any fuel used maintaining idle on a descent or slowing for a junction is actually wasted.

The base engine of the Golf is a turbocharged, direct injection engine producing 85PS between 4300rpm and 5300rpm. The rolling-road fuel consumption of the new 1.2 TSI is 4.9l/100km (equivalent to 113g/km CO2). Turbocharging has boosted torque compared to the old entry-level 1.4 MPI from 132Nm to 160Nm; this is delivered between 1400rpm and 3500rpm. The new engine is 1.5l/100km more economical — a fuel savings of 23 per cent.

An 85PS TSI engine was also available as an option in the previous model; compared to this version, and with an identical power output, fuel consumption has been reduced by 0.6 l/100km.

Next up is the 1.2 TSI with 105PS. On the rolling road, the Golf with this engine consumes 4.9l/100km (equivalent to 114g/km CO2). This represents a saving of 0.3l/100km compared to the previous model. The maximum power of this engine is available from 4500rpm to 5500rpm; torque of 175 Nm is delivered between 1400rpm and 4000rpm.

As an alternative to the standard 6-speed manual gearbox, this engine can be ordered with a seven-speed DSG; in this case, fuel consumption is reduced to 4.8l/100km (112g/km CO2).

The 1.4 TSI with 122PS delivers its maximum power between 5000rpm and 6000rpm. Maximum torque is 200Nm, available from 1400rpm. Rolling-road fuel consumption is 5.2l/100km (equivalent to 120g/km CO2), which is 1.0l/100km less than in the previous model. A seven-speed DSG is available as an option; it reduces fuel consumption by an additional 0.2l to 5.0l/100km (116g/km CO2).

A more powerful 140PS version of the 1.4 TSI is available. This unit already meets the limits of the Euro 6 emissions standard. Maximum power is delivered between 4500rpm and 6000rpm; combined fuel consumption is the same as the 12w2PS variant, at 5.2l/100km (119g/km CO2). Fitted with the 7-speed dual clutch gearbox, fuel consumption is reduced to 5.0l/100km (116g/km CO2). This engine will also be offered in a second version with automatic cylinder deactivation (ACT). Fitted with ACT, NEDC fuel consumption drops to 4.7l/100km (equivalent to 109g/km CO2). The Golf 1.4 TSI also returns these figures with the optional seven-speed DSG. The TSI offers a maximum torque of 250Nm between 1500rpm and 3500rpm.

The EA211 petrol engine series

The new engine family comprises three- and four-cylinder units. The engines of the EA211 series made their premiere at Volkswagen with the production launch of the Up as a three-cylinder MPI.

Fuel consumption values and CO2 emissions of the EA211 engines were reduced by 8 to 10 per cent, in part due to reduced internal friction, lower mass and improved thermal management; in conjunction with the innovative new cylinder deactivation system (ACT), the savings potential can be as much as 23 per cent.

The engines of the EA211 series are also characterised by a new mounting position. In the familiar petrol engines of the previous EA111 series, the (‘hot’) exhaust side was at the front, and the engines were mounted with a forward tilt. By rotating the cylinder head, EA211 engines are now tilted towards the firewall, like the EA288 diesel engines, at an identical inclination angle of 12 degrees. A positive result is that Volkswagen can now standardise the exhaust line, driveshafts and gearbox mounting position.

The EA211 is a complete redesign; only the cylinder spacing of 82mm was carried over from Volkswagen’s successful EA111 engine series. That the engine is also compact is reflected in its mounting length, which has been shortened by 50mm. This is an advantage that passengers in the new Golf will experience directly in the form of a more spacious interior, because it was possible to shift the front axle forward (relative to the hip-point). An aluminium block reduces mass by up to 16kg; thanks to an ultra-rigid crankcase made of die-cast aluminium, the new petrol engines are especially lightweight at 97kg (1.2 TSI) and 104kg (1.4 TSI). On the 1.4 TSI, the weight advantage compared to the grey cast iron counterpart from the EA111 series is as much as 22kg. This approach to lightweight design extends down to the smallest details: engine developers reduced the main bearing diameter of the crankshaft on the 1.4 TSI from 54mm to 48mm; the crankshaft itself was lightened by 20 per cent., while the weight of the connecting rods was reduced by 30 per cent. The rod bearing pins are bored hollow. The aluminium pistons, now with flat piston crowns, were designed for reduced mass.

By fully integrating the exhaust manifold into the cylinder head, the coolant heats up quickly from a cold start, warming both the engine and the car’s climate control system. At high loads, the exhaust gas is cooled by the coolant, which reduces fuel consumption by up to 20 per cent.

Volkswagen has designed the EA211 with a dual-loop cooling system. The head and block are cooled by a high-temperature loop with a mechanically driven coolant pump, while a low-temperature loop, powered by an electric pump, circulates coolant to the intercooler and turbocharger housing as needed. Passenger compartment heating comes from the cylinder head circulation loop, so that it warms up quickly.

Volkswagen uses a very narrow single-scroll compressor for turbocharging. This reduces the mass of the cylinder head turbocharger component group. On the EA211, the intercooler is integrated in the induction pipe which is made of injection-moulded plastic. The advantage of this arrangement is more rapid pressure build-up.

Internal friction is an important element in engine design. In the case of the EA211, the camshafts are driven by a single stage, low-friction toothed belt design with a 20mm wide belt and load-reducing profiled belt wheels. Thanks to its high-end material specification, this toothed belt’s service life reliably spans the entire life of the vehicle. Actuation of the valve drive via roller cam followers and an anti-friction bearing for the highly loaded first camshaft bearing also lead to reduced friction.

To ensure that the engine takes up as little mounting space as possible, ancillary components such as the coolant pump, air conditioning compressor and alternator are screwed directly to the engine and the oil sump without additional brackets, and they are driven by a single-track toothed belt with a permanent tension roller.

To reduce emissions and fuel consumption, and to improve torque in the lower rev range, timing of the intake camshaft on all EA211 engines can be varied over a range of 50 degrees crankshaft angle. On the 1.4 TSI with 140PS, the exhaust camshaft is variable as well. Engine response at low crankshaft speeds benefits from variable valve timing.

Five-hole injection nozzles deliver fuel at up to 20MPa. Up to three individual injections are delivered to each of the cylinders by means of a stainless steel distributor bar.

In designing the combustion chamber, Volkswagen paid attention to achieving minimal wetting of the combustion chamber walls with fuel.

Alfa Romeo attempted active cylinder management in the 1980s, but the results were not impressive and the idea was not brought to market. Thus Volkswagen is the first car-maker to implement such a system, on the 1.4 TSI 140PS. Temporarily deactivating the second and third cylinders can save over 0.5l of fuel per 100 km, depending on driving style. The system is active between 1400rpm and 4000rpm and with an engine load of up to 85Nm. Volkswagen claims that this covers 70 per cent. of driving states in the NEDC driving cycle — though not necessarily in real life. All mechanical switchover processes take place within one camshaft rotation; depending on engine speed, this takes between 13ms and 36ms. Accompanying interventions in ignition and throttle valve processes smooth the transition.

Altogether, the components of active cylinder management weigh just 3kg. Their actuators, the camshafts and their bearing frames are integrated in the cylinder head; two low-friction bearings reduce shaft friction. Only with direct injection is cylinder deactivation practicable in the form being implemented today.

The EA288 diesel engines

The entry-level Golf diesel is a 1.6 TDI with 105PS. Rolling-road fuel consumption over the NEDC cycle is 3.8l/100km (equivalent to 99g/km CO2). Its maximum power is available between 3000rpm and 4000rpm, and its maximum torque of 250Nm is maintained between 1500rpm and 2750rpm. As an option, this model can be ordered with Volkswagen’s seven-speed dual-clutch gearbox. In this case, combined fuel consumption is marginally worse at 3.9l/100km (equivalent to 102g/km CO2).

The Golf Blue Motion uses a variant of the 1.6 TDI with more sophisticated injection kit which offers 110PS. Combined fuel consumption is 3.2l/100km (equivalent to 85g/km CO2). As always, these are dynamometer figures. This engine’s torque output is 250 Nm — the same as the 105PS unit and delivered over the same rev range. The Golf Blue Motion is available only with a manual gearbox — a five-speed unit.

The two-litre TDI with 150PS delivers a combined fuel consumption figure of 4.1l/100km (equivalent to 106g/ km CO2). This unit has two balancer shafts. Maximum power is available between 3500rpm and 4000rpm; maximum torque of 320Nm is delivered between 1750rpm and 3000rpm. This Golf is available with an optional dual-clutch gearbox (the high torque six-speed DSG); thus equipped, the car’s combined fuel consumption rises to 4.4l/100km (equivalent to 117g/km CO2).

The 150PS turbodiesel of the EA288 series replaces the excellent EA189 unit which offered 10PS less. The new engine consumes 0.2l/100km less on the dynamometer, with CO2 emissions reduced by 8g/km. Like the new EA211 petrol engines, the only dimension of the Golf’s new four-cylinder diesels that is the same as that of the previous model is the cylinder spacing. Many components were designed to be modular thanks to the new modular diesel component system (MDB). They include emissions-relevant components such as the fuel injection system, turbocharger and intercooler within the induction manifold module. In addition, a complex exhaust gas recirculation system is used (with a cooled low-pressure EGR). Also new on all Golf TDI engines is the layout of emissions control components to locate them nearer to the engine. To fulfil various emissions standards worldwide, an oxidation catalytic converter, a diesel particulate filter and NOx storage catalytic converter are used.

Along with reducing hazardous emissions, Volkswagen has designed all sub-assemblies of the new TDI for minimal internal friction. These actions include piston rings with less pre-tension and the use of low-friction bearings for the camshaft (drive-side) and — in the two-litre version — for the two balancer shafts. In the oil circulation loop, energy usage is reduced by the use of an oil pump with volumetric flow control.

During the warm-up phase, the thermal management system uses separate cooling circulation loops for the cylinder head and the cylinder crankcase as well as an on-demand coolant pump which can shut off completely. Thus the TDI engines reach operating temperature quickly and the interior of the car gets warmer more swiftly in the winter. Another independently controlled cooling loop enables on-demand control of charge air temperature with additional emissions control benefits.

Dual-clutch gearboxes (DSG)

For a detailed description of the Volkswagen seven-speed dual clutch transmission, click here.

Most engines of the new Golf can be paired with a dual-clutch gearbox (DSG). It is either a six-speed or seven-speed DSG, depending on the maximum engine torque.

Besides the number of forward gears, other technical aspects differentiating the two DSG units include the clutch type. While two dry clutches are used in the 0AM seven-speed DSG, the high-torque 02E six-speed DSG has a dual clutch that runs in an oil bath.

Running-gear

The new Golf platform is known internally as the Modular Transverse Matrix — ‘transverse’ referring to the driveline. Running-gear for the new car is an evolution of existing practice, with weight-saving being a significant aim.

A new rear suspension was developed for the engine versions with less than 122PS. This is known as the ‘modular lightweight suspension’, and it weighs just 38kg. For the more powerful engine versions, the ‘modular performance suspension’ is used — this weighs 49kg. In front, Volkswagen has used a McPherson system; the lower wishbones are new, and it features a track-stabilising scrub radius. All components have been reworked. The result, despite not using aluminium components, is a weight saving of 1.6kg. This was made possible by, for example, the use of high-strength steel in the transverse links and an innovative ‘bionic’ (inspired by nature) design approach to the pivot bearings. A subframe is centrally positioned on the front axle; its frame — designed for maximum transverse rigidity — handles loads from the engine mounts and steering as well as loads of the front suspension components.

The tubular anti-roll bar has a new range of spring rates. The rubber bearings are vulcanised directly onto the painted anti-roll tube; this improves acoustic properties. With the 16-inch and 17-inch brakes, a new aluminium pivot bearing was also developed. The use of aluminium and the bionic design of this pivot bearing enabled a weight reduction of 2.8kg.

The new modular lightweight suspension consists of a transverse profile that is open at the bottom, into which an insert plate is welded at the outer ends. Different torsion rates for different versions are obtained by different lengths of the insert plates. This yields a considerable weight advantage compared to a welded-in tubular anti-roll bar. The use of a transverse profile that is open at the bottom in the layout also provides good roll-steer behaviour and high transverse rigidity. By using high-strength steels and innovative design methods, Volkswagen succeeded in significantly increasing rigidities compared to previous suspensions of this construction type. Despite this, its weight was reduced. Compared to the modular performance suspension of the Golf versions with more engine power, a weight saving of 11kg is achieved here.

The rear suspension of the seventh generation Golf has been further developed from the perspectives of improved kinematics, acoustics, mass distribution and ‘modularity’. However, nothing has changed with regard to its fundamental approach of consistently separating longitudinal and transverse rigidities. The low longitudinal rigidity has been preserved by the soft axle control of the trailing link; this was a necessary precondition for further improving ride comfort. The transverse rigidity of the modular performance suspension has been improved by the use of new tuning for the tie rod bearing. Tracking and camber values are individually tuned by excentric screws on the spring link and at the upper transverse link according to requirement for each vehicle type.

Key design changes to the rear suspension are the connections of the tubular anti-roll bar and the suspension damper, which are now made at the spring link. This reduces forces within the suspension; there are also significant package advantages. In addition, the suspension was made 4.0kg or 8 per cent. lighter in weight by structural changes to many components and the use of high-strength steels.

• We will append a table of technical data when the information becomes available.

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