For a company that prides itself on its engineering heritage – Volkswagen has been rather late to the hybrid party. It’s a party in which the Japanese are considerably ahead of the game – Toyota is on its second generation Prius while Honda has just released the world’s cheapest hybrid, the Insight. Volkswagen on the other hand has concentrated on developing BlueMotion technologies which, when allied to small capacity diesel engines, meets both the fuel consumption and emission targets without either the cost or complexity of current hybrids.

Hybrids though are what environmentally conscious customers are demanding, especially in the United States – the world’s largest car market – which explains VW’s first hybrid the Touareg V6 TSI Hybrid prototype. The hybrid drive on this prototype will make it to production on the all-new Touareg due next year. OverDrive( April ’09) gives us an insight…

At the heart of the Touareg Hybrid is the V6 TSI petrol engine which uses a combination of petrol direct injection and super-charging to deliver a power output of 333PS and maximum torque of 440Nm. The newly developed engine is mated to VW’s first ever eight-speed automatic transmission specifically adapted for hybrid use. And nestled between the engine and transmission is the hybrid module. Weighing 55kg this module houses the disengagement clutch and electric motor (which also functions as the alternator and starter motor) that adds 52PS of power and up to 300Nm of torque.

Nickel-metal hydride batteries are housed in the boot – they weigh in at 67kg, consist of 240 individual cells and generate 288 volts – and the interplay of all these components is controlled by the hybrid manager integrated into the ECU.

Like the Prius, when you turn the key, the V6 engine doesn’t fire up and the Touareg runs silently only on the batteries. It remains in electric mode at speeds of up to 50kmph but to keep it in electric drive the driver has to be careful not to accelerate too hard, otherwise the V6 engine will kick in. 

When speeds pick up or the batteries don’t have sufficient charge, the engine is started by the electric motor which drags the engine up to a set speed after which the clutch is engaged, cylinders are filled and the motor is fired by enabling injection and ignition. It is a complicated procedure permitted by a high level of electronic sophistication but behind the wheel the transition is silent and jerk-free; almost imperceptible and terrifically refined marvels OverDrive (April ’09).

Claimed fuel consumption is 11.1kmpl in hybrid mode which is a 25 percent fuel saving in city driving and 17 per cent reduction in combined city and highway driving. Co2 emissions are less than 210g/km meeting Euro 5 and American ULEV2 emissions standards. Along with the hybrid drive there are a number of fuel saving techniques employed on the Touareg including stop-start, regenerative braking and coasting assist which disengages the engine during coasting (even at speeds as high as 160kmph) eliminating the mechanical drag effects and reducing consumption. There’s also a switchable engine water pump, redesigned electro-hydraulic power steering, lighter Torsen differential similar to that of the Audi Q7 and a high voltage air-con compressor that keeps the cabin cool even when the engine is switched off.

Of course ultimately the efficiency depends on how well the driver employs all the systems on hand and adapts his driving style. To that effect there is a comprehensive map on the central information display that shows where the power is coming from, what the instantaneous fuel consumption is and coaxes the driver into a more fuel conserving frame of mind.

Of course when you floor it the efficiency plummeted to single digits (the acceleration really is incredible) – and that’s the bottom line – even with all the technology in the world, saving the planet finally boils down to the person behind the wheel concludes OverDrive (April ’09).