Media information february 2011
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February 2011 Spotlight AWD The all-wheel-drive system in detail The 4x4 version of the Captiva features the ITCC (Intelligent Torque Controlled Coupling) modern all-wheel-drive system from Japanese supplier JTEKT. The system is also incorporated in the latest generations of the Toyota RAV4 and the Opel Antara. Its key elements are two clutches – an electromagnetic pilot clutch and a hydraulic multi-disc wet clutch. Electronically controlled, they vary the distribution of the propulsion force between the front and rear axles. The advantages of this construction compared with conventional solutions are that it is maintenance-free, compact and lightweight. At the same time, the system responds instantly and prevents tension in the drivetrain, as can happen, for example, with a rigid connection of the axles.
The main components – the PTU (Power Transfer Unit), propeller shaft, rear halfshafts and RDM (Rear Drive Module) with clutches – together weigh no more than 75 kg. Fuel consumption is correspondingly low. With the 2.2-liter turbo diesel engine and manual transmission, the five-seat all-wheel-drive Captiva consumes only 0.3 l/100 km more than its front-wheel-drive counterpart (MVEG mix). The all-wheel-drive system communicates via the high-speed CAN data bus with the electronic control program and receives important information like the rpm of all wheels, the steering angle and the accelerator position, evaluating the data on a permanent basis. Normally, the Captiva is a straight front-wheel-drive vehicle, which means that the clutch to the rear axle is opened. However, if the electronic system identifies a need to intervene, it will, within 100 milliseconds, redistribute the torque between the front and rear axle. Any power ratios between 100:0 and 50:50 are possible.
If the system decides that the rear axle should come into play, the control unit will provide power to the solenoid coil of the electromagnetic pilot clutch, resulting in a magnetic field. The field strength attracts an anchor in the clutch, whereby the force of attraction behaves almost in proportion to the voltage. A mechanism known as the ball-ramp system subsequently functions as a power amplifier. A ball lies in two concave-shaped cams. Because the first cam is pushed upward by the closing pilot clutch, the second is pushed forward axially by the ball. As a result, the multi-disc wet clutch is pressed together. The greater the pressure on the main clutch, the more force is finally transmitted to the rear axle. About Chevrolet Chevrolet is General Motors' largest global brand with annual sales of about 4 million vehicles in more than 130 countries. It is the fourth biggest global car brand in terms of sales and also one of the fastest growing brands in the world. Chevrolet cars combine passion, bold design and practicality. They provide outstanding value for money. After re-launching the brand in Europe in 2005, Chevrolet more than doubled its sales to over 500,000 in 2008. In 2010, Chevrolet grew its market share in Europe to 2.5 percent, selling 477,194 cars. Chevrolet has a network of more than 2,700 dealers and service points in Europe. The Chevrolet line-up includes the Spark city car, the small Aveo, the compact four-door Cruze, the Captiva SUV and the legendary Corvette sports car. In 2011, Chevrolet is launching seven new cars: the all-new Orlando family van, the new Captiva SUV, the Corvette Grand Sport Coupé, the all-new five-door and four-door Aveo, the five-door Cruze, the Camaro coupé and convertible and the award-winning extended-range Volt electric car. Chevrolet's biggest markets in Europe are Russia, Italy, Germany, Spain, France and Turkey. Established in the U.S. by Swiss émigré Louis Chevrolet in 1911, the brand is celebrating its centenary in 2011. More information on Chevrolet can be found at http://www.chevroleteurope.com or http://media.chevroleteurope.com. Contacts: Marc Kempe Dr. Karin Kirchner Chevrolet Europe Chevrolet Europe Phone +41 44 828 2980 Phone +41 44 828 2518 Mobile +41 79 201 5752 Mobile +41 79 605 2557
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