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MQB-based 7th gen VW Golf up to 100 kg lighter and 23% more fuel efficient than predecessor; Golf BlueMotion delivers 3.2 l/100km (73.5 mpg US) and 85g/km CO2
5 September 2012
|World premiere of the new Golf in the New National Gallery in Berlin. Click to enlarge.|
Volkswagen staged the world premiere of the new Golf in Berlin. The new Golf—the seventh generation of a vehicle that has been on sale since 1974 with sales totaling 29.13 million cars—is based on the Modular Transverse Matrix (MQB, modularen Querbaukasten). (Earlier post.)
Basing the new Golf on the MQB had far-reaching consequences; this Golf was completely redesigned in practically every area—the vehicle body, the interior, the engines, all of the information and entertainment systems and the numerous new driver assistance systems. Weight was reduced by 100 kg (220 lb). Elements carried forward were in the main technical features that were already future-proof in the previous model—the six- and seven-speed direct shift gearbox (DSG), for example.
Volkswagen developed two completely new engine generations that offer a power range from 63 kW / 84 hp to 110 kW / 148 hp for the Golf. Every version is fitted as standard with a Stop/Start system (reducing fuel consumption by up to 4%) and brake energy recovery mode (cutting CO2 by around 4%). With all measures combined it was possible to reduce CO2 emissions by up to 23%. The Golf BlueMotion sets the new efficiency benchmarks for the model series with CO2 emissions of 85 g/km and a combined fuel consumption of 3.2 liters of diesel per 100 km (73.5 mpg US).
This duty to build sustainable cars in large numbers is something that we’ve always been conscious of here at Volkswagen. It was therefore important to us to build the most fuel-efficient Golf ever, which at the same time had to remain affordable. And we’ve succeeded in doing that. The Golf Mk7 is extremely fuel efficient, equipped as standard with the Stop/Start system and brake energy recovery mode and yet—to take Germany as an example—at a base price of €16,975 not a cent more than its predecessor’s entry level model.—Prof. Dr. Martin Winterkorn, Group Chairman, Volkswagen AG
Driver profile selection. For the first time the Golf is now also being offered with a driver profile selection system, a tool with which forward-thinking drivers can achieve a particularly efficient style of driving. There are a total of four—and, in combination with DCC (adaptive chassis control), five—driving modes available: Eco, Sport, Normal, Individual and, in combination with DCC, Comfort.
In the Eco driving profile engine management, air conditioning and other ancillary systems are controlled such that optimum fuel consumption is achieved. In addition on vehicles with DSG when driving in Eco mode there is a coasting function available. If a driver takes his or her foot off the accelerator—for example, when drawing up to traffic lights or on downhill stretches—the DSG disengages and the engine idles. As long as the driver drives appropriately, the Golf’s kinetic energy can thus be put to optimum use.
The gasoline engines. The EA211 family gasoline engines used are exclusively turbocharged and direct-injection TSI engines (four valves, four cylinders). The gasoline engines offered at launch on the new Golf deliver 63 kW / 85 PS / 84 hp and 103 kW / 140 PS / 138 hp. The base model offers an average fuel consumption figure of just 4.9 l/100km (48 mpg US), equivalent to 113 g/km of CO2—0.6 liters less than the previous corresponding model.
For the first time there will also be a Golf with cylinder cut-off (ACT active cylinder management). The model fitted with this is a 140 PS TSI, which already satisfies the future EU6 standard. Average fuel consumption is 4.8 l/100km (49 mpg US), or 112 g/km CO2. By way of comparison: the 18 PS weaker corresponding engine in the already fuel-efficient previous model (90 kW / 122 PS) consumed 6.2 l/100km (37.9 mpg US), or 144 g/km CO2.
With ACT, at low- and medium-load, two of the cylinders are shut off, which reduces fuel consumption in the EU driving cycle by 0.4 l/100 km. The cut-off system becomes active between 1,400 and 4,000 rpm at a torque level of up to 85 N·m (63 lb-ft)
The diesel engines. The diesel injection engines, also four-cylinder, four-valve versions and here too generally turbocharged, initially deliver 77 kW / 105 PS / 103 hp and 110 kW / 150 PS / 148 hp. The TDI base model with 105 PS delivers average fuel consumption of 3.8 l/100km (62 mpg US), or 99 g/km CO2. The Golf Mk6 achieved this figure only with the BlueMotion model—not, however, with the base model as is the case with the new Golf.
The Golf’s 150 PS TDI offers average fuel consumption of 4.1 l/100km (57.4 mpg US), or 106 g/km CO2.
100 kg weight reduction. Weight reduction in the new Golf was achieved as follows:
- Up to -6.0 kg = Electrical
- Up to -40.0 kg = Engines
- Up to -26.0 kg = Running gear
- Up to -37.0 kg = Superstructure
In purely mathematical terms the total potential saving is thus even as much as 109 kilograms. Due, however, to the configuration options that can be implemented in practice, the maximum achieved in any one vehicle is 100 kg, Volkswagen said. The greatest weight reduction is achieved from the engines and superstructure.
For the superstructure, the reductions came as follows:
-0.4 kg = Dashboard. Volkswagen not only succeeded in making the dashboard 20% lighter thanks to a new thermoplastic foam injection process—the load-bearing, sandwich-like structure beneath the elegant surface consists of this material—but also in making it 20% more rigid at the same time.
-1.4 kg = Module cross-member (beneath dashboard). Mounted on the module cross-member are both the steering gear and the dashboard. Altogether the cross-member weighs 5.8 kg. The reduction in weight was achieved with a lightweight construction concept using steel components. Based on an analysis by Finite Element Method (FEM) computations, the structure of the module cross-member was designed to be as light as possible and as strong as necessary.
Optimal steel wall thicknesses and structural design measures, such as specially worked-in corrugations, improved the rigidity of the cross-member, while also reducing its weight by the 1.4 kg. Utilizing methods such as the Finite Element Method, engineers at Volkswagen are essentially emulating examples found in nature, where the natural world is able to attain an astonishing ratio between the cross-section of a part’s structure and its rigidity—e.g. in a stalk of grass or grain.
-2.7 kg = Air conditioning. The Golf’s entire air-conditioning system has been redesigned and is 2.7 kg lighter. Independent of its weight, all of the Golf air-conditioning units with their highly efficient refrigerant cycles set standards in terms of comfort and efficiency. They run very quietly (up to 5 dB(A) lower), reach the desired temperature significantly faster and are very energy-efficient (up to 4 Amps less) due to a new type of blower control with intelligent climate control. The 2.7 kg weight reduction is achieved by such design modifications as optimized thickness of various system components walls, reduced diameters of pressure lines, a new fastening system and a weight-optimized high-performance heat exchanger.
- -7.0 kg = Front and rear seats (depending on version). Along with numerous minor modifications to the seats, weight was reduced—especially from the rear backrests—to save a total of up to 7 kg. Once again, the Finite Element Method (FEM) and high-strength steels combined with laser welding made it possible to optimise wall thicknesses and profile geometries. Engineers achieved weight savings of more than 15% in this way and by using lighter backrest latch mechanisms.
-23.0 kg = Body. The body must be strong and rigid to guarantee optimal safety and maximum comfort. Nonetheless, its structure should remain lean, so that the overall vehicle is light and efficient. Harmonizing strength and weight continues to be one of the greatest challenges in the automotive world. Highly expensive materials like aluminium, magnesium or even carbon-fiber are therefore excluded in the Golf’s segment. Instead, Volkswagen says, it is relying on the synergies of the MQB, innovative utilization of high-strength steels and advanced production methods. The result is a 23 kg reduction in weight with more stringent crash and rigidity requirements as well as larger vehicle dimensions.
-2.5 kg = Miscellaneous.
New systems for optimized safety and convenience.
New assistance systems include the multi-collision brake—the Volkswagen Group is the only carmaker to implement such a system as standard in a compact car—a proactive occupant protection system, standard XDS electronic differential lock (as found in the previous-generation Golf GTI), ACC adaptive cruise control plus Front Assist and a City Emergency Braking function, Lane Assist lane-keeping assistant, fatigue detection, traffic sign recognition and the latest generation of the automatic parking assistant ParkAssist including OPS (360 degree display) as well as the automated light functions Light Assist and Dynamic Light Assist.
There are other new technologies as well, such as progressive steering (optimized dynamic performance and better comfort), the selection of driving profile with five modes (‘Eco’, ‘Sport’, ‘Normal’, ‘Individual’ and, in combination with DCC, ‘Comfort’), an electronic parking brake, a newly developed ergonomic sport seat (ergoActive seat), a guard against using the wrong fuel in the diesels, a new climate comfort windscreen that is also a first in this segment and a new generation of information and entertainment systems.
Multi-collision braking system. The Golf’s multi-collision braking system has already won a safety innovation award from Germany’s largest automobile club (ADAC). Studies in accident research have found that approximately one-fourth of all traffic accidents involving personal injury are multiple-collision accidents.
The multi-collision braking system automatically brakes the vehicle when it is involved in an accident in order to significantly reduce its residual kinetic energy. Triggering of the multi-collision braking system is based on detection of a primary collision by the airbag sensors. Vehicle braking by means of the multi-collision braking system is limited by the ESC control unit to a maximum deceleration rate of 0.6 g. This value is the same as the deceleration level provided by Front Assist. The driver’s ability to control the car is thus assured even when automatic braking is triggered.
The driver can ‘override’ the multi-collision braking system at any time; for example, if the system recognizes that the driver is accelerating, it gets disabled. The automatic system is also deactivated if the driver initiates hard braking at an even higher rate of deceleration. In essence, the multi-collision braking system applies the brakes until a vehicle speed of 10 km/h is reached. This residual vehicle speed can be used to steer to a safe location after the braking process.
Proactive occupant protection (PreCrash). Proactive occupant protection is a typical example of a technology that is being transferred from the luxury class to the compact class. Volkswagen first implemented the proactive occupant protection system in the Touareg. Now the system is making its debut in the Golf, making it one of the few vehicles in its class anywhere in the world to offer such a protection system.
If the proactive occupant protection system detects a potential accident situation—such as by the initiation of hard braking via an activated brake assistant—the seatbelts of the driver and front passenger are automatically pre-tensioned to ensure the best possible protection by the airbag and belt system. When a highly critical and unstable driving situation is detected—such as severe oversteer or understeer with ESC intervention—the side windows (except for a small gap) and sunroof are closed. That’s because the head and side airbags offer optimal support and thereby achieve their best possible effectiveness with windows and sunroof almost fully closed.
Adaptive cruise control. Until now, adaptive cruise control (ACC) was reserved for vehicles in higher segments such as the Volkswagen CC or Phaeton. Now ACC has arrived in the compact class with the Golf. The system uses a radar sensor integrated into the front of the car. ACC operates over a speed range from 30 to 160km/h (19 to 99 mph) with a manual gearbox and from 0 to 160 km/h with DSG (dual clutch gearbox).
On vehicles with DSG the Adaptive Cruise Control intervenes to such extent that depending on the situation the car gets slowed to a standstill and in Stop-and-Go mode automatically pulls away. ACC maintains a preselected speed and a defined distance and 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 on the new Golf.
Front Assist. Front Assist works like ACC with the radar sensor integrated into the front of the car, which permanently monitors the distance to the traffic ahead. Even with ACC switched off, Front Assist helps the driver in critical situations by preconditioning the brake system and alerting the driver by means of visual and audible warnings to any required reaction. If the driver fails to brake hard enough, the system automatically generates sufficient braking force to avoid a collision. Should the driver, meanwhile, not react at all, Front Assist automatically slows the car so that under optimum conditions the speed of any impact is minimised. The system also assists the driver by providing a warning if the car is getting too close to the vehicle in front. The new City Emergency Braking function is part of Front Assist.
City Emergency Braking function. The City Emergency Braking function, now available for the Golf for the first time, is a system extension of Front Assist and scans via radar sensor the area in front of the car. The new system works at speeds below 30 km/h. If the car is in danger of collision with a vehicle driving or parked up ahead and the driver fails to react, the brake system gets preconditioned in the same way as with Front Assist. If necessary, the City Emergency Braking function then initiates full application of the brakes in order 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. This system, which was first introduced in the current Passat, 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 behavior. Once under way, the fatigue detection system continually evaluates signals such as steering angle. If monitored parameters indicate a deviation from the steering behavior recorded at the beginning of the trip, then visual and acoustic warnings are produced. Independent of this monitoring, whenever the system is activated it recommends a driving break to the driver after 4 hours of continuous driving.
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—used for the first time in the Golf—can now also maintain continuous tracking support, which optimises comfort and convenience. 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. Conventional steering systems operate with a constant gear ratio. However, the new optional steering system in the Golf operates with a progressive gear ratio. This noticeably reduces steering work in maneuvering and parking. On country roads with lots of bends and in turning, meanwhile, the driver will notice a gain in dynamic performance due to the more direct gearing; the driver also does not need to turn the wheel as much.
Technically, progressive steering differs from the basic steering system by the rack and pinion’s variable tooth spacing and a more powerful electric motor. Its functional difference: unlike with constant steering ratios, which by necessity always represent a compromise between dynamic performance and comfort, here the steering rack’s toothing is modified by the steering stroke. As a result, the transition between indirect steering behavior in the mid-range (straight-line driving) and direct steering behavior at larger steering wheel angles is designed to be progressive, which, as mentioned above, enables significantly more agile steering behavior in dynamic driving situations. Parking the car thus becomes more comfortable, as the wheel needs to be turned less.
Variable ratios have long been known in the area of hydraulic steering systems; however, the tuning of such a steering system is subject to very tight limits, so that the driver is not overtaxed by the transitional behavior. With the Golf’s new progressive steering system, the combination of the steering rack’s progressive steering ratio and the tuning potential of an electro-mechanical steering system is systematically exploited in the Golf to realize optimized steering behavior that is sporty yet practical in everyday driving.
Electric parking brake. The electric parking brake is already applied in larger Volkswagen cars, such as the Passat or Tiguan. Now, this handbrake is also making its way into the Golf. Instead of a handbrake lever, there is a main control switch plus an Auto Hold switch on the center console. The electric parking brake offers numerous advantages: eliminating the conventional hand-brake frees up more space on the centre console; in addition, the brake is automatically released when driving off, making hill starts easier. Last but not least, the Auto Hold function prevents unintentional rolling from a standstill position.
Dynamic Light Assist. Via a camera on 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 65 km/h (40 mph) and stays on. With the help of the camera, the system masks the main beam modules of the bi-xenon headlights with dynamic cornering lights only in those areas that it calculates could potentially disturb other road users. This function is technically implemented by a pivoting masking aperture between the reflector with the xenon filament and the lens. Along with lateral swiveling 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. For models with headlights with no dynamic cornering light, the base version of the automatic main beam assistant is available. Light Assist analyses traffic ahead and oncoming traffic—via a camera in the windscreen —and automatically controls activation and deactivation of the main beam (at 65 km/h and above).
Road sign recognition. Road sign recognition initially made its debut in the Phaeton. In the new Golf it will be available in combination with a satellite navigation system. If via a camera integrated in the windscreen near to the rear-view mirror the recognition system recognizes any speed limit or ‘No overtaking’ signs, up to three of these will get shown on the combined instrument panel in front of the driver and on the navigation system’s display.
This will also include all additional information and the signs will appear in a logical order: ones that always apply (e.g. a 130 km/h speed limit) get shown in first place, while signs that only apply at certain times (e.g. 80 when wet) appear in second place. If the rain sensor registers that it is starting to rain, the traffic sign that now comes into force, i.e. the ‘When wet’ sign, moves up into first place.
Park Assist 2.0. The latest version of the 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 40 km/h (25 mph) by pressing a button on the center 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 maneuvering distance of 40 cm front and back 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. Beeps 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.
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