COVER You STORY will find
theVW figuresMultivan mentioned in this article in the German issue of ATZ 12/2003 beginning on page 1144.
Der neue Volkswagen Multivan
The New Volkswagen Multivan In summer 2003 Volkswagen Commercial Vehicles launched the campaign for its new models with the new Multivan. The group's largest multi-purpose vehicle is a luxury vehicle and will join the ranks of VW's other new premium vehicles, the Phaeton and the Touareg. Given its practical interior functionality, its size and motoring properties, the new Multivan occupies a vehicle segment its classic predecessors created for themselves: the segment for maxi vans.
1 Introduction
By Erwin Pape, Ernst-Peter Otto and Gabriela Heiser
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On the 23rd April 1947, the Dutch importer, Ben Pon, made some rudimentary drawings of a vehicle type that had previously never been seen in the world: a front wheel drive vehicle with rear engine and box body shape. These drawings were the start
of a new vehicle category that is now in its fifth generation. And from the latest development, it is already clear that the T5 or Multivan following the T4 too is a benchmark and trendsetter in its class. Despite its fresh design, the new Multivan immediately has a familiar feel to it. The geometric lines, the tight shutlines of
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the doors, bonnet, tailgate and lights, the large glass panels, the wider track and body give it an unmistakable, dynamic character. Table 1 shows the exterior dimensions and weights. The interior is distinguished by an innovative design, sumptuous materials and close attention to detail, and with its clear layout and symmetry, the ideal in high functionality and quality is given. The Multivan structure is made up of four equipment levels: ■ Multivan with one sliding door, sidewall folding table, air conditioner ■ Multivan Comfortline with two sliding doors, multifunction table, two swivel seats, leather steering wheel ■ Multivan Highline with leather/ Alcantara equipment, wood, electric sliding doors, 3-zone Climatronic, anti-theft alarm system ■ Multivan Business full range of equipment for communications and luxury.
shafts. Due to the fact that these gearboxes are filled-for-life, they are completely maintenance free. All gearboxes have a single plate clutch, which operates from a dualmass flywheel. The only exception is the 2.0 litres petrol engine with the MQ250 gearbox. In this vehicle category, the automatic gearbox is the first of its kind in the world with transverse installation and 6 speeds. Intelligent selection by means of two planetary gear sets and a minimum number of friction coupling elements allow a very compact form. A four-wheel drive system is also available for the new Multivan. This utilises the trusted Haldex coupling from the Golf platform. It supports all traction control systems and can transmit a maximum torque of up to 2000 Nm to the rear axle. Table 3 shows the available engine/gearbox combinations.
2 Engines and Transmissions
3 Running Gear
The Multivan can be fitted with a choice of three diesel engines, high in torque, weight optimised and low in fuel consumption, or a choice of two smooth running petrol engines with increased power output. Combined with an innovative 6-speed manual or automatic gearbox, performance and comfort have been improved yet even further. The performance data are listed in Table 2. The Diesel engines are a 1.9 litres four cylinder TDI engine with 77 kW and 250 Nm, a 2.5 litres five cylinder TDI engine with 96 kW and 340 Nm at 2000 rpm and a 2.5 litres five cylinder TDI engine with 128 kW, with the same basic form, but which develop 400 Nm at 2000 rpm. Same as 96 kW engine in its basic form but develops 400 Nm at 2000 rpm. The Petrol engines are a 2.0 litres four cylinder engine with 85 kW and 170 Nm at 2600 rpm and a V6 3.2 litres engine with four valve technology and 173 kW with 315 Nm at 2950 rpm. The new Multivan features a choice of two newly developed manual gearboxes and one automatic gearbox with three performance levels. The MQ250 gearbox is a newly developed 5-speed manual gearbox for 4-cylinder engines. It has a torque capacity of up to 250 Nm. A new inner selector mechanism and synchronisation were developed to improve comfort in selecting gears. The MQ500 gearbox is installed in conjunction with the R5 and V6 engines. It is the first manual gearbox of its kind with 6 gears and transverse installation and has a maximum torque output of up to 500 Nm. The extremely compact dimensions are thanks to a new layout of the gears and
The completely new concept of the running gear is distinguished by track stability, agility and safe handling, thereby giving the new Multivan the typical driving properties of a conventional car. Anti-roll bars at both axles, Figure 1 and Table 4, reduce the roll axis of the vehicle while suspension comfort is improved by load-dependent dampers.
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3.1 Front Axle
McPherson suspension struts are installed on the front axle with lower wishbones, an acoustically decoupled suspension subframe, that also contributes towards crash safety, and a four-point pendulum mounting for engine and gearbox with two torque reaction supports. To reduce body roll, an anti-roll bar is installed with a diameter of 23 mm (25 mm on sports running gear). This operates in direct vicinity of the wheels and features a special shape, which makes the anti-roll bar extremely effective. By introducing this component as a standard feature, the front coil springs could be made softer for a more comfortable ride. The front coil springs are installed offset to the axis of the front suspension, which leads to a notable reduction in lateral stress on the dampers and thus positively influences suspension response and driving comfort. By optimal positioning of the suspension struts, a negative steering roll radius was realised as well as a reduction in the road feedback lever arm. The introduction of a 2nd generation wheel bearing made it possible to minimise negative influences on the steering system thanks to a reduction in the bearing clearance. The toe-out variable, responsible for
VW Multivan
the straightening properties and centrepoint response of the steering, is 82 minutes at a steering angle of 20 degrees, and is thereby adapted to the castor angle giving a turning circle of 11.9 m (T4 = 12.1 m). 3.2 Rear Axle
The rear axle of the T5 is a further development of the trusted semi-trailing arm axle from the T4 with miniblock springs and separate dampers. Anti-roll bars are installed as standard for the first time (24 mm in diameter, 28 mm in diameter on sports running gear). The T4 version, constructed from welded sheet metal, has been replaced by a fully cast part. With an increased maximum permissible axle load this allows a reduction in specific material usage. To improve acoustics and comfort, two large rubber bushes are installed in the semi-trailing arm mountings on the body. The rubber bushes in the coil spring and damper mountings on the body and semi-trailing arm are also featured throughout with greater volume to absorb axle vibrations. The vibration dampers, located behind the centre of the rear wheel with a strong incline towards the interior of the vehicle, are of the load-dependent, grooved damper type due to package reasons. 3.3 Road Handling
Even at development stage, there were clearly formulated road handling guidelines (lift and elastokinematics, mounting points etc.) and there was an intensive elementary and fine tuning programme of the running gear during the prototype phase. With conventional running gear technology, this made it possible to achieve an improvement in terms of driving stability, safety, comfort and agility over the vehicle's predecessor; a predecessor that is still greatly respected even by today's standards. With a tendency to understeer, the lift kinematics at both axles are a successful sythnesis of good driving stability and low tyre wear. The elastokinematics of the front axle also give the vehicle understeering properties when it is subjected to lateral forces, Figure 2. The rear axle is set to toe-out, when subjected to lateral forces, due to its design concept. Its minimisation allows large volume, direction sensitive semi-trailing arm bearings, which meet the demands on minimal rolling noise and good rolling comfort. In order to optimise rolling comfort and engine acoustics without the road handling properties being affected adversely, the suspension subframes were decoupled from the body. The mountings were designed as a compromise between fav-
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VW Multivan
ourable acoustics and driving stability. The wishbones of the front axle feature a heavy duty bearing at the front to improve road handling. The trailing arm supension is important to ensure good rolling properties and is further enhanced by the rear kidney shaped bearings that are softened laterally. All bearings and joints are designed with low hysteresis properties and, together with a feature on the suspension struts that counterbalances lateral force, a good suspension response is assured, even over minor bumps. An important element when determining the characteristics of the running gear and balance between the axles is the response of the dampers. Installed on both axles are travel-sensitive grooved dampers that provide good suspension comfort when the vehicle is unladen and supply the necessary degree of damping when the vehicle is fully laden. The dampers are finetuned to each of the different vehicle body and equipment versions. During the dynamic tests, such as sharp steering, lane change, evasive action, slalom etc, a high level of good-naturedness is achieved up to a wide limit range, which gives the driver adequate time to counteract. The permissible towing weight is up to 2,500 kg with consideration to the "critical speed" in terms of driving stability (start of undampened swinging motion of pull). 3.4 Brakes
The brake system of the Multivan consists of single piston floating calipers and ventilated brake discs allround; Table 5 shows the brake data. To improve active safety, a brake assist system has been installed for the first time. It supports the normal braking effect at increased pedal speed, that is during emergency braking situations, by applying additional force and thereby assuring valuable and maybe even lifesaving stopping distance. The maximum brake pressure in the brake master cylinder is built up faster, which eases ABS intervention. The larger tandem brake servo considerably reduces the amount of pressure that has to be exerted on the pedal by the driver. 3.5 Steering
The servo-supported rack and pinion steering is distinguished by low operating forces and high precision. With a ration of 1:15.8, only 3.3 turns of the steering wheel are required from stop to stop. Figure 3 shows a schematic diagram of the steering column. 3.6 Traction Control Systems
The T5 is fitted as standard with ABS, traction control system (TCS) and engine brak-
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ing control (EBC). The system includes electronic brake pressure distribution (EBDP). In addition, the stability of the vehicle is maintained further by an advanced system that detects braked cornering situations. By combining engine and brake intervention, the TCS achieves an optimum in steering ability, traction and comfort across the whole speed range when the vehicle is accelerated. With the help of brake intervention at each of the wheels, the electronic differential lock (EDS) utilises major differences in friction at the driving wheels for optimal propulsion. Combined with engine torque reduction, the result is an improvement in comfort. In corners, the TCS counteracts the understeer in performance and thereby contributes considerably towards steering stability. The EBC works in a coupled state when the ABS is active. After pressure builds up, the speed of the driving wheels is not increased quickly enough to that of the engine with its braking effect. The result is long lasting wheel slip, which reduces steerability. The EBC system sends a signal to the engine management to increase the engine speed briefly. The driving wheels are released from the engine torque effect, with negative influence, and can therefore transmit greater lateral guiding forces. As an option, an electronic stabilisation programme (ESP) is available, including brake assist system. If by evaluation of the signals ESP detects that there is a risk of instability, the vehicle is stabilised within the scope of physical barriers by intervention in the engine management system or braking of individual wheels. The stabilising counter torque is combined, if necessary, with the driver's braking input. 4 Body
Directionally stable running gear places high demands on stiffness and rigidity of the body. Together they allow a high level of safety and are a prerequisite for good vehicle acoustics. By the use of multi-layered pillars and sills in conjunction with high tensile panels, the dynamic natural frequency and resistance to fatigue was increased. The body structure is of a shell design, Figure 4. This concept allows the most important properties, such as torsional rigidity, fatigue strength and crash response to be achieved efficiently with optimal material usage. The combination of shell design and tailored blanks and the application of laser welding and metal bonding means that a dynamic stiffness in the body of approx. 30 Hz could be achieved in the first torsion natural frequency. This means it is 20%
higher than the T4 even though the number of spot welds was reduced. In addition to the positive effects of laser welding and metal bonding, an optimal reduction in noise generation is achieved thanks to cavity insulation. The underbody trim, new for this vehicle category, improves aerodynamics with a Cd factor of 0.35 and also protects the underside of the vehicle against stone chips. The integrated noise insulation tray reduces exterior noise when the vehicle is overtaking or being overtaken. This concept means that there is no longer a requirement for large volumes of PVC. 5 Interior
The Multivan offers a space concept that combines variability, functionality and comfort. The variable interior offers a multitude of seat layout and storage features thanks to the comprehensive stowage concept and a new rail system integrated in the floor of the passenger compartment. The cockpit, Figure 5, is well presented, functional and ergonomic. It offers, among other things, clear and easy to read round instruments, height and rake adjustment of the steering wheel and a comprehensive range of stowage facilities. The joystick gear selector allows easy access to the rear and offers a high level of ergonomic comfort thanks to short gear changes. The driver and front passenger seats are height adjustable as standard and have an adjustable lumbar support, armrests on both sides and side airbags. To enhance the ergonomic features even further, the front seat adjustment in the longitudinal plane was increased by 30 mm compared to the T4. All passenger seats in the rear are anchored in the rail system and can be positioned freely in the interior. Installed in the front row of seats are two swivel seats, depending on the equipment level, which also feature armrests on both sides. The backrest angle can be adjusted for optimal seating comfort and can also be tilted further to a 66° position to easy entry. A table function can also be created by folding down the single swivel seats or reclining bench seat. For the rear seat row there is a three seater bench seat fitted as standard, which can be easily converted into a sleeping surface, Figure 6. As an option, two fixed single seats can also be ordered. Both the single seats and the bench seat are equipped with stowage compartments in the seat frames. These can be removed to allow a through-loading aperture. The seatbelts in the rear are integrated in the seats, which helps to maintain the
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variability in layout for the sleeping surface and offers the occupants a high level of safety at each position. The basic version of the Multivan follows tradition with one sliding door, which is equipped with a folding sidewall table. In the sidewall are diverse stowage elements such as bottle holder, cupholder and waste bin. The Comfort and Highline versions are equipped as standard with two sliding doors with integrated side windows. The sidewall table is replaced in favour of a multi-function middle table. This is also installed separately in the floor rails and can be positioned freely. The high level of variability of the interior concept is also reflected in the layout of the luggage compartment. Variable volumes are achievable by moving the seats forwards or even removing them altogether to allow a maximum of 4,500 litres. 6 Climatisation
The basic equipment consists of a manual air conditioning system with an additional heater for the passenger compartment. All air conditioning units are distinguished by a high output of warmed or cooled air. To support the heating, a fuel burning auxiliary heater is installed. The 3-zone Climatronic, Figure 7, fitted as standard in the Highline version, allows the temperature on the driver's and front passenger's side to be regulated individually. Integrated in the system are functions such as residual warmth utilisation and automatic air recirculation and sensors to detect harmful emissions. The pollen and activated charcoal filters are located on the pressure side behind the fan. Vents in the B pillars with fan support in the doors keep the side windows free of condensation: The auxiliary coolant heater and auxiliary heater can be activated via remote control. In addition to central operation from the cockpit, a separate operator unit in the light strips of the rear headliner allows regulation from the rear. Furthermore, each passenger has the option of changing the headliner vents to direct or indirect output. Integrated in the A/C and light strip are also halogen reading lamps, which can be directed individually for each seat. 7 Safety
Great care and attention was placed on the safety features of the body and these comprise many single measures. The longitudinal members act as main load carriers, which are programmed to deform specifically in an accident. The stiffness of the longitudinal members is maintained continu-
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ally to the occupant cell. This results in optimal distribution of crash energy in the case of an accident. At collision speeds of up to 15 km/h, two deformation cups in each bumper absorb the impact energy so that the longitudinal members behind them are not damaged. The reinforced wheel housing increases stability in the doorframe. This makes it easier to open the front doors after an accident and thereby aids rescue of the occupants. Large volume sill panels, side impact members in the doors and the high seating position, inherent for this type of vehicle, offer the best protection for occupants at both the left and right side of the vehicle. A new feature is the decoupled suspension subframe on the front axle, which is bolted to the body via vibration absorbing bearings. Seated on this suspension subframe is also the main part of the power unit. In addition, it also serves as a second, lower crash level. The steering column is equipped with deforming crash elements. It folds together in a front collision by means of telescopic shafts. A deformation element in the upper steering column offers additional travel of up to 50 mm with a defined force-travelmap for the driver. The dash panel is designed to absorb energy to minimise head and body injuries as far as possible. The new Multivan is fitted as standard with driver/front passenger, side and curtain airbags, Figure 8. The front passenger airbag can be deactivated by means of a key lock in the glove compartment if a child's seat is secured at the front. The seat-integrated seatbelts of the single seats feature a child safety function. This prevents repeated retraction of the belt and thereby makes it possible to safely attach standard child seats. In addition, each single seat features Isofix mountings, which allow external child seats to be integrated in the vehicle structure. The advantage is that incorrect operation of the restraining systems is largely avoided. 8 Electrical/Electronic System
The wide range of functions are based on CAN bus technology. This allows electronic elements to communicate with each other. The innovative digital voice enhancement (DVE) system, Figure 9, allows the passengers to converse freely even at high vehicle speeds or high external noise levels. The hands-free device gives all occupants the opportunity to follow telephone conversations – and also to participate in them. The output telephone signal and also the voice input signal in the vehicle are cleaned of disturbances to a high level. The DVE sys-
MATERIALS
tem recognises where the voice input originates from, the relevant microphone is then activated and the signal is combined with the audio signal. The technical basis for this feature is a radio or radio navigation unit and the sound system of the Multivan. 9 Recycling/Environmental Protection
As with all new models from the Volkswagen Group, the new Multivan features a fully galvanised body. The galvanised panels are all treated with the proven corrosion protection system. This is made up as follows: Zinc phosphate application, cathode dip paint, water-based filler coat, waterbased colour coat and two-pack clear coat. The cavities are preserved by means of the Volkswagen patented wax flooding system. These and other measures allow a three year guarantee on the paintwork and a twelve year guarantee against rust perforation. The use of an underbody trim cover made from polypropylene means that there is no longer a need for PVC corrosion protection measures on the vehicle underside. Environmental measures across the entire life-span resulted in ecological advantages by the use of these new variants. This means that in terms of recycling, for example, a considerable improvement was made. The new dash panel consists exclusively of polypropylene. The use of a single material for the entire structure means recycling is made easier as complicated separation and sorting of the sandwich construction is no longer necessary. Thanks to the application of the newest materials and technologies, the material odour in the interior was practically eliminated. 10 Forecast
The complete model range of the new T5 from Volkswagen comprises the derivatives shown in Table 6. Information about the commercial vehicle and 4motion will be provided in a later edition. ■
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