COVER You STORY will find
Caddy theVW figures mentioned in this article in the German issue of ATZ 4/2005 beginning on page 270.
Der neue Caddy von Volkswagen
The New Caddy from Volkswagen
By Erwin Pape and Carsten Gliesche
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Volkswagen Commercial Vehicles has successfully launched the third generation of the Caddy onto the market, where it competes in the light commercial vehicle segment. It employs Volkswagen’s current A-class modules and is presented in a modern, attractive design, perfect for a small van used on urban runs. The Caddy responds to the particular requirements of its customer group, such as maximum utility at high levels of comfort, superior safety standards, an attractive appearance both inside and out, simple operation, good ergonomics and excellent value for money, something that is a high priority in this segment.
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1 Introduction
The Caddy is a modern all-rounder and expands the Volkswagen Commercial Vehicles product range in the small van segment. The Caddy started out as a new development project at the Simultaneous Engineering Centre (SEC) in Wolfsburg, where Digital Mock-Up (DMU), Virtual Reality (VR) and Digital Data Control Model (DDCM) techniques, as well as the latest systembased processes, were used to bring it to life. The result is the Caddy box-body van – the commercial vehicle variant – the Caddy minibus and the Caddy Life. The Caddy offers three rows of up to seven seats and can carry a maximum load of 750 kg in a load area of up to 3200 litres. 2 Body
The combination of a layered construction, Figure 1, tailored blanks and high-strength panels/steels, as well as the use of laser soldering and bonding methods has greatly enhanced the dynamic natural frequencies and the fatigue strength of the body. In terms of the body’s dynamic rigidity, a value of 35 Hz has been achieved for the first natural torsion frequency. The vehicle includes more than 24 metres of bonded seams. The outer skin of the Caddy’s body is electrolytically galvanised to prevent corrosion. Hot-dip galvanising has been used to protect the floor space and the interior. The Caddy is produced with two basic bodies, the box-body and the minibus. It can be fitted with a large sliding door on both sides. The Caddy box-body van can also be ordered with fixed sidewalls. The sliding door provides an opening 700 mm wide and 1108 mm high. The central door runner is made of high-grade steel. Vehicles with a second sliding door are fitted with an automatic blocking feature that protects the fuel filler flap. When the fuel filler flap is open, the blocking catch swings outwards and prevents the sliding door from opening more than half way. The load/passenger compartment can be accessed at the rear through a tailgate that opens to a height of over two metres. Two asymmetrically split, side-hinged rear doors are available as an alternative. They can be swung through 90° or, with the door stays released, through approximately 170°. A ladder hatch attachment can be ordered for transporting tall, bulky objects. This consists of a frame element, the SMC (sheet moulding compound) surround for the opening roof panel and a pane of tinted safety glass fixed into the panel. The folddown crossbeam is designed to support a
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weight of 500N. A visual indicator guards against operator error by showing if the crossbeam is securely fixed in place. The ladder hatch has been designed so that it can be operated with just one hand. The hatch can be opened to an angle of 40° and easily shut again thanks to a comfortably reachable loop handle. The Caddy minibus body offers a total of nine different structural variants, the Caddy box-body van twelve, Figure 2 and Figure 3. 2.1 Caddy Box-Body Van
The box-body version can be easily recognised from the outside, due to its big, flat side panels, which are free of indentations. These provide a large, uninterrupted space for advertising. The even loading surface is 1781 mm long and offers six load tie-down points. It can be fitted with a removable, anti-slip PUR load bed cover. The sidewalls of the load compartment are fitted with hardboard to half their height. The load compartment offers a maximum volume of 3200 litres at a maximum height of 1257 mm and a maximum interior width of 1558 mm. The through-loading width between the wheel arches is 1170 mm. The load compartment is separated from the driver’s compartment by a fixed plastic partition, which is shaped so as to give the driver maximum room for adjusting his or her seat. The top part of the partition consists of a mesh grille that allows the driver a rear view and includes integrated interior lighting for the front of the load compartment. A half-width partition is also available, with a wooden loading surface on the passenger side. In future, it will also be possible to order a Vario partition with a hinged door, in combination with a folding seat on the passenger side. 2.2 Caddy Minibus and Caddy Life
The second-row footwell contains recessed storage compartments with robust, lockable covers. As an optional extra, four storage nets can be screwed to the roof frame of the passenger compartment. These are useful for holding small objects and each comes with two coat hooks. A removable, hinged luggage cover is also available, the rear part of which can be folded back to make loading easier. The Caddy minibus can transport up to seven people in three rows of seats, Figure 4. The passenger compartment includes a three-seat bench as standard. All seats are fitted with three-point safety belts, with the belt for the middle seat integrated into
VW MATERIALS Caddy
the backrest. The fold-down backrests require no mounting brackets on the body. This improves loading access to the luggage compartment and also facilitates easier access for passengers climbing into the third row. Passengers enjoy a superior level of comfort thanks to the high seating position and the ergonomically adjusted padding. The bench is split 2/3-1/3 and each backrest can be independently folded down into a horizontal table position and fixed in place. Each backrest can also be separately tipped forward in order to expand the luggage compartment up to a maximum volume of 3020 litres. The tipping movement is supported by gas-operated dampers and does not require the headrests to be removed. In order to secure them for transport, the seats are fastened to the floor of the vehicle using an integrated support rod. A two-seat bench can be ordered for the third row as an option. It can be quickly locked into place and released without the need for tools, while the backrests can again be folded down into a horizontal position. Just as in the second row, the freestanding backrests again ensure that there are no mounting brackets on the body to get in the way. If the third row of seats has been removed, the seatbelt fittings can be stowed in the side trim, thereby allowing unrestricted use of the luggage space. The Caddy Life is based on the Caddy minibus. It differs in the upgraded equipment level of the body and interior. It has moulded trims in the sliding doors and rear sidewalls; these house additional storage compartments, loudspeaker mounts and a plug socket. The seats are covered with high-quality coloured fabric. Standard equipment includes a second sliding door, remote control central locking, the R100 radio, electric front windows, electrically-adjustable heated door mirrors, a height-adjustable drivers seat with underseat storage drawer, 15” full-size wheel trims, fog lights, fabric-covered door trims with chrome door catches at the front and a large centre console fitted with passenger air vents and rear cup-holders. 3 Equipment and Electrics
The Caddy interior also offers many practical features that mean added benefit for the customer. The use of Volkswagen’s Aclass modules ensures a generous amount of room for the occupants. The vehicle has been designed in such a way that it can be operated with maximum ergonomic comfort, while the high seating position offers an excellent all-round view. There are a range of storage options. In addition to storage compartments on the dashboard and in
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the centre console, there is a large overhead shelf with room for the logbook and several DIN A4 folders. Generous door pockets provide space for drinks bottles up to 1.5 litres in size, contingent upon the model. And depending on the equipment version, there are up to four cup-holders in the centre console. The Caddy’s practical electrical features are controlled via the CAN bus [1]. One feature that deserves special mention is the automatic air recirculation provided by the air conditioning system. When the system recognises that the vehicle is moving backwards, it activates the automatic air recirculation in order to prevent the vehicle’s own exhaust fumes entering the interior. The rear window wash/wipe system is also activated automatically when reverse gear is engaged and the front wipers are on [2]. A manual heating and ventilation system, as well as the Climatic semi-automatic air conditioning, ensure comfortable in-car conditions. Both systems use air conditioning devices of identical construction. In the case of Climatic, the chosen interior temperature is automatically maintained even if external conditions change. Climatic is fitted with an ECON(omy) button that allows the driver to switch off the compressor and thereby reduce fuel consumption. In winter, the ECON(omy) mode also switches off the heater booster system. For diesel models a fuel powered heater booster system has been developed with a heat output of 5 kW. The point at which it is activated depends on the outside temperature, coolant temperature and heating requirements. The heater booster warms the coolant and compensates for the lack of heat generated by the diesel engines, which have been optimised for fuel consumption. The interior is therefore heated more quickly, improving occupant comfort at very low outside temperatures. An auxiliary water heater can also be ordered as an optional extra. In terms of combustion, it is based on the same principle as the heater booster system. The coolant piping contains an integrated solenoid valve that, when activated, disconnects the heating circuit from the engine cooling circuit. The coolant will then only circulate between the auxiliary water heater and the heat exchanger in the heating/air conditioning system. When the coolant reaches a temperature of 50 °C, the heater fan is activated and the interior heated to the temperature set on the air conditioning controls. The auxiliary water heater can be programmed by following the menu prompts on the multi-function display and the instrument panel. It can also be activated by pressing the instant heating button on the
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air conditioning controls or via an optional radio remote control. When driving, the auxiliary water heater automatically functions as a heater booster for the engine. 4 Chassis
The Caddy uses many of the new system components from the Volkswagen A-class, notably the modules for the front axle, electric power steering (EPS), braking system (new 11” dual-rate brake servo) and hand and foot controls [3]. Modified for use in the Caddy, and accompanied by the newly developed rear axle, these modules help to ensure optimum driving characteristics. Tried-and-tested Golf technology was adopted for the front axle (suspensionstrut-type axle with triangulated lower wishbones), the only change being an additional ground clearance when unladen of around 30 mm and corresponding adjustments to the springs and shock absorbers. The rear leaf-sprung rigid axle, however, is a new development, Figure 5. This type of axle offers the best compromise between the priorities of through-loading width, space requirements and safety at excessive loads. In order to achieve the desired handling properties – neutral to understeer – the designers took advantage of the roll effect, not forgetting the kinematically improved leaf spring pick-up points. In the minibus versions of the Caddy, the resulting goodnatured driving characteristics are also optimised in terms of ride thanks to the use of PST (position-sensitive twin-system) shock absorption technology – a world first for a volume-production vehicle. This technology features a dual piston system with spiral bypass channels etched onto the inside diameter of the pressure tube, Figure 6. This technology, unlike other road-adaptive shock absorption systems, offers a greater range between “hard” and “soft” in both the extension and the compression stage. It therefore presents considerable advantages, especially for vehicles with a high load-to-weight ratio (high maximum load). Rear axle suspension comprises leaf springs with a stiffness range of 35 N/mm to 46 N/mm. These are fitted as standard and, in combination with Cellasto auxiliary springs, determine the suspension characteristics of the rear axle. The Caddy Life is fitted with a 1+1 progressive parabolic spring, which provides stiffness of 32 N/mm for optimum ride when empty or partially-loaded, and 50 N/mm for optimum load-carrying when fully-loaded. The front and rear axles are fitted with 15” disc brakes. Depending on the engine,
there is an option of two floating calliper designs with ventilated disc brakes for the front axle. The rear axle is fitted with an aluminium floating calliper brake with integrated handbrake function and a sturdy brake disc, ensuring that it can cope well with the maximum axle load of 1250 kg. The brake system is fitted with the Continental-Teves MK 70 M-ABS system (including EBD, TCS and EBC), again selected from existing platform modules and fitted as standard. Caddy minibus customers have the option of ordering an ESP control system (MK 60). This has been taken from an existing platform and modified to meet the requirements of the Caddy. The Caddy’s Electronic Stabilisation Program includes the following features, which are familiar from the Golf: ■ ABS: Anti-lock brake system ■ EBD: Electronic brake pressure distribution ■ ESBS: Electronic stabilisation program (braking only) ■ TCS: Traction control system ■ EDL: Electronic differential lock ■ EBC: Engine braking (effect) control ■ HBA: Hydraulic brake assist ■ LDE: Low-dynamic ESP ■ Overboost: Hydraulic auxiliary boosting. The use of electric power steering, or EPS for short [4], means that less strength is required for parking manoeuvres and provides a solid feel for the road, even at high speeds. The fact that EPS adjusts to each situation results in a drop in fuel consumption compared to conventional hydraulic steering systems. Other advantages are the small unit size and the disappearance of the need for hydraulic oil and peripheral components. Furthermore, the diagnostic capability of the steering system makes it possible to quickly and accurately identify damage during servicing, thereby avoiding the need for an expensive new part. 5 Vehicle Safety
A key focus of development, in addition to body rigidity, was crash safety. The Finite Element Method (FEM) was used to define features that would specifically improve the performance of the bodyshell structure and restraint system under crash conditions. In the event of a head-on collision, the stable passenger cell structure remains intact. This is achieved in part thanks to reinforced window surrounds in the door openings and high-strength panels in the sill areas, while the floor has been further strengthened in order to reduce footwell deformation. In the event of a side-impact
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6 Engines and Transmission Table: Engine data of the VW Caddy
collision, the side reinforcements in the doors provide the best possible protection for occupants. The Caddy features three-point safety belts in all seats. Front occupants are protected by front and side airbags, as well as belt tensioners with belt force limiters. The crash characteristics of the steering column and the foot controls have also been improved [3]. Isofix attachments for the outside seats in the second row complete the safety equipment. These allow child seats to be form-fitted into the vehicle structure. The passenger-side airbag can be deactivated by operating a key switch in the glove compartment. A deactivation light will then show on the centre console. 6 Engines and Transmission
Four different drive units can be installed in the Caddy, Table: 1.4-litre and 1.6-litre petrol engines, delivering 55 kW and 75 kW respectively, a direct unit injection natural-
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ly-aspirated 2.0-litre diesel engine (SDI) with 51 kW, and a unit injection 1.9-litre TDI with 77 kW. The latter can pull a trailer load of up to 1500 kg. The engines meet the Euro 4 standard and are equipped with a service interval display that indicates when the next service is due. All four units are fitted with a five-speed manual gearbox as standard, which has been modified for the different engine torque levels in each case.
The vehicle and safety equipment employs the latest technology in order to meet the requirements of demanding commercial vehicle users as well as family- and leisure-oriented car users. References [1]
7 Summary [2]
With the launch of the new Caddy, Volkswagen Commercial Vehicles has introduced a new class of small van. Big on the inside, compact on the outside, it offers many different uses and is at the same time easy to operate. The new Caddy comes in a range of structural variants, has a large load area and employs new technology components, thanks in part to the use of the current Volkswagen mid-size platform.
[3]
[4]
Behrend, P.; Hoffmann, C.; Krömke, C.; Valentini, H.-D.: Bordnetz und Vernetzung im neuen VW Golf (On-board computer and networking in the new VW Golf).In: Der neue Golf: Special issue of ATZ and MTZ on the new Golf, October 2003, pages 90-92 Falz, F.; Schönfeld, P.; Schrödter, A.; Ortmann, F.; Klempt, A.: Licht und Sicht im neuen VW Golf (Light and vision in the new VW Golf – wiper system). In: Der neue Golf: Special issue of ATZ and MTZ on the new Golf, October 2003, pages 96-97 Rischbieter, F.; Maus, D.; Manz, H.; Blumberg, S.; Hoffmann, F.; Schebsdat, K.; Van de Weerd, M.; Klopp, H.: Das Fahrwerk des neuen VW Golf (The chassis of the new VW Golf). In: Der neue Golf: Special issue of ATZ and MTZ on the new Golf, October 2003, pages 74-89 Kwasny, O.; Manz, H.: The Electromechanical Steering System of the VW Touran. In: ATZ Worldwide (2003), issue no. 5, pages 464-470
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