4MOTION, the four-wheel drive system from Volkswagen, offers enhanced active safety and driving pleasure. In 2006 the new Passat will be available in three different engine versions with the latest 4MOTION system. The top model of the Passat range, the 184 kW / 250 PS Passat 3.2 V6 FSI 4MOTION, has the most effective form of power distribution as standard. The 4MOTION drivetrain is available as an option with the Passat 2.0 FSI (110 kW / 150 PS) and the Passat 2.0 TDI (103 kW / 140 PS). The permanent four-wheel drive system is available for the Passat saloon and estate in combination with all equipment lines (3.2 V6 FSI 4MOTION: starting with the Comfortline).
4MOTION took over from syncro
Permanent four-wheel drive also enhances the handling of the Golf, Sharan, Multivan, Phaeton, and Touareg. Volkswagen has been building Passat's with four-wheel alongside front-wheel drive for over two decades; the first model, the Passat estate GT syncro, was launched in 1984. To date over 256,000 Passat drivers worldwide have opted for four-wheel drive.
4MOTION is powerful
The Passat comes equipped for the first time with a 4MOTION system featuring Haldex coupling. The coupling, which is fitted directly in the rear axle, is considerably more compact and the system works quickly, sensitively, and quietly. Four-wheel drive also delivers major advantages for towing trailers. The Passat 3.2 V6 FSI 4MOTION, for example, pulls a hefty maximum trailer weight of 2 200 kg on uphill grades of up to 12 percent. Its gross weight rating for the rear axle is 1 220 kg. For the Passat 2.0 TDI 4MOTION a maximum trailer weight of 2 000 kg is allowed on uphill grades of up to 12 percent and 2 200 kg on up to 8 percent grades - in each case 200 kg more than with the front-wheel drive Passat 2.0 TDI. All Passat's with a towing attachment also have ESP with special trailer stabilisation as standard.
4MOTION is adaptable
The central element of the 4MOTION system is a multi-plate wet coupling (in an oil bath). It is called the Haldex coupling as it was developed together with Swedish systems partner Haldex who have worked with Volkswagen for many years. The Haldex coupling has the major advantage of being electronically controlled and having a very fast response. This allows it to work very effectively in conjunction with the anti-lock braking system (ABS), the traction control system (TCS), the electronic differential lock (EDL), and the electronic stability programme (ESP) – all these assistance systems are fitted as standard in the Passat.
4MOTION is always active
As soon as differences in the speeds of rotation between the front and rear axles occur two annular piston pumps are activated which build up pressure in the multi-plate coupling (Haldex system) thus "coupling" the two axles to each other. The transmitted torque can be varied by adjusting the pressure on the coupling plates, thus controlling the flow of power between the front and rear axles. The coupling provides an infinitely variable torque transfer between the front and rear axles. In extreme cases up to 100 percent of the available torque can be transmitted to the rear axle. In the normal case with the vehicle travelling in a straight line at a constant speed with no differences in the wheels' grip, 90 percent of the available torque is transmitted to the front axle and ten percent to the rear axle. The Haldex coupling is driven by the propshaft.
4MOTION is fast
The coupling responds to "commands" from the 4MOTION electronic control unit extremely quickly. As soon as the Haldex coupling registers front axle slip, the required torque is transmitted to the rear axle. The compact coupling can transmit a torque of 3 200 newton metres to the rear axle.