- Feb 2, 2009
Volkswagen Touareg Hybrid with supercharged V6 joining BlueMotion offerings
Click above for a gallery of the Volkswagen Touareg BlueMotion Hybrid
Volkswagen is set to launch a Touareg BlueMotion Hybrid in 2010. The new machine will be the first real production hybrid from the German company and will join the automaker's expanding BlueMotionTechnologies lineup. In addition to the Touareg headliner, VW has announced a diesel-powered Passat BlueMotion, a Passat BlueTDI that's able to achieve 2014 Euro-6 emissions regulations today, and a natural gas-fueled Passat TSI EcoFuel.
The Touareg BlueMotion Hybrid will feature a supercharged 3.0L TSI V6 engine that's shared with the Audi S4 along with a new 8-speed automatic transmission. While many would likely be awfully pleased just to see that drivetrain in the Touareg, the big news is what's sandwiched between them, namely, a 38 kW electric motor that gets power from a 288-volt nickel-metal hydride battery pack.
A similar hybrid system is expected to make an appearance in the upcoming Porsche Panamera and offers up 374 horsepower and 406 lb-ft of torque to all four wheels in this application. That's enough to push the bricklike Touareg to 62 mph (100 km/h) in just 6.8 seconds and, perhaps more importantly, deliver a European combined rating of 26.1 mpg (U.S.). That's an improvement of 25% over the normal Touareg, though it will surely come with a price tag to match. See all the details after the break.
BlueMotionTechnologies - Touareg V6 TSI Hybrid
Prototype: Touareg Hybrid with new V6 TSI can tow 3.5 metric tons
Charged V6 TSI and E-motor drive fuel consumption below 9 liters
Hybrid module was integrated between V6 TSI and 8-speed automatic
Wolfsburg, 02 February 2009
In parallel to pure gasoline and diesel versions, Volkswagen will be bringing the next version of the Touareg to market as a hybrid version too. Average fuel consumption: less than 9.0 liters fuel per 100 kilometers. CO2 emissions: less than 210 g/km. For the first time, there is now a near-production prototype that offers initial glimpses of the full hybrid technology that will be implemented on the future Touareg. This experimental platform has its conceptual basis in the current generation of the SUV. The car's powertrain already embodies many aspects of the future Touareg Hybrid. It will be powered by a new V6 TSI – a highly advanced gasoline direct injection engine boosted by a mechanically-driven supercharger – in tandem with an electric motor. It will have a newly developed 8-speed automatic transmission. Volkswagen will be implementing a parallel hybrid drive on the future Touareg V6 TSI Hybrid. This version of the SUV will have a high-performance, full-time all-wheel drive too.
V6 TSI stands for maximum power with minimum consumption
The V6 TSI on the Touareg prototype is fun to drive and delivers 245 kW / 333 PS at 5,500 rpm. From its 2,995 cm3 displacement, it generates a maximum torque of 440 Newton-meters starting from 3,000 rpm. These characteristics match those of the Touareg with an eight cylinder engine, yet with the V6 TSI it is significantly more fuel efficient. This represents the principle of intelligent downsizing (less displacement plus gasoline direct injection plus inlet boosting) already established by Volkswagen on the globally successful TSI four cylinder engines, and it is now being applied to six-cylinder engines. The results are convincing. The substantial torque delivery that came from using a supercharger becomes even more fascinating with the addition of the E-motor, especially at low speeds. If required, an exceptional amount of torque is available from a standstill – a bonus that comes from a system that is designed for efficiency. To increase further this efficiency, the V6 TSI makes use of a switchable engine water pump. This remains off during the warm-up phase, ensuring rapid achievement of fuel efficient operation.. The pump is integrated into the vehicle's overall heat management system.
V6 TSI plus E-motor drives fuel consumption below 9.0 liters
The E-motor integrated between the V6 TSI and the 8-speed automatic transmission adds power of 38 kW / 52 PS and up to 300 Newton-meters torque. In so-called boosting – where requests for maximum power and torque (by kickdown or gearshift selector in "S" position) are supported by the engagement of both V6 TSI and electric drive systems – the powertrain briefly supplies a power of 275 kW / 374 PS and the maximum available torque increases to 550 Newton-meters. In this case, the Touareg V6 TSI Hybrid prototype accelerates to 100 km/h in just 6.8 seconds.
The hybrid system of the Touareg was not designed to deliver sports car performance. Its purpose is to deliver very low emissions and fuel consumption values. It may therefore come as a surprise to learn that this exceptional performance is accompanied by an average fuel consumption of less than 9.0 liters per 100 kilometers. CO2 emissions are less than 210 g/km. The Touareg V6 TSI Hybrid will attain the limits of the Euro-5 and American ULEV2 emissions standards.
More than 25 percent better fuel economy
Compared to a conventional SUV of the same size, the hybrid concept yields fuel savings of more than 25 percent in city driving. Development engineers calculate an average savings of 17 percent in combined city, highway and freeway driving. Essentially, there are four parameters with which the Volkswagen prototype achieves this improved fuel economy.
Start-stop system: an integrated start-stop system significantly reduces fuel consumption, especially in urban driving.
Regenerative braking: during braking, the E-motor operates as a generator and recovers energy, which is then stored in the high voltage battery (NiMH batteries). This means that the E-motor recovers a proportion of the energy that would otherwise be rejected in the form of heat through the braking system. It comes into effect progressively during the initial travel of the brake pedal.
The E-motor: The vehicle can operate on the electric motor alone at speeds of up to 50 km/h, which reduces fuel consumption in city driving. In this case the V6 TSI is turned off, and it is disconnected from the transmission by a disengagement clutch. In this condition the Touareg V6 TSI Hybrid operates with zero emissions. Electric current flows from the battery to the E-motor via the power electronics which incorporates a pulse controlled inverter. On the later production version, there are also plans for a special E-switch that the driver can activate for pure electric driving.
Coasting: as soon as the driver removes his or her foot from the gas pedal, a clutch disengages the V6 TSI from the transmission. This is even possible at higher speeds – in the later production version up to about 160 km/h – and therefore in freeway driving as well. This eliminates mechanical drag losses, which in turn makes the Touareg coast significantly better. The driver can convert this directly into improved fuel economy by adopting an anticipatory driving style.
Intelligent energy mix
With regard to powertrain types – and their associated energy flows – besides electric driving and coasting there are two other operating modes: classic driving with internal combustion engine and the boosting that is typical of hybrid vehicles.
When driving with just the internal combustion engine, there are two possible modes of operation. In the first case, the Touareg is driven like a conventional vehicle with the E-motor performing the function of a conventional 12 V alternator, which it replaces, to supply sufficient energy for the vehicle's electrical system and maintain battery charge (in this case a high voltage battery). In the second case, the engine supplies the energy needed to propel the vehicle plus the energy needed to charge the high voltage battery via the E-motor, but at a higher rate, replacing energy taken from battery when in conditions when the E-motor has been operating as an electric motor. This so-called load point shifting makes it possible to operate the engine at a more favorable level of efficiency in the engine load/speed map. The job of hybrid control is now to regulate this alternation of electric driving phases and active charge phases to achieve minimal fuel consumption.
Boosting: when the driver consciously activates a request for maximum power (kickdown or gearshift lever in "S" position), the E-motor supports the V6 TSI beyond the engine's full-load curve. The powers and torques of these two motors are then transferred to the front and rear axles by the 8-speed automatic transmission. As previously mentioned, this briefly makes available a total combined power of up to 275 kW / 374 PS and a maximum torque of 550 Newton-meters.
In addition, since it can be controlled extremely quickly the E-motor is also used – in the framework of so-called transient compensation – to make positive and negative torque interventions. For example, when the driver makes a positive load request the E-motor briefly boosts the V6 TSI until it has reached its steady-state target value. This allows the Touareg Hybrid to keep accelerating. Negative torque interventions largely replace classic interventions via the internal combustion engine that are not optimal for efficiency, but are needed for occupant comfort during gear shifting or sudden charge changes.
The specific mode that is activated is shown by an energy flow indicator in the display of the RNS 510 radio-navigation system installed in the prototype vehicle.
Basic technical layout of the hybrid drive
Volkswagen has chosen a parallel hybrid drive for use in the Touareg. In contrast to other possible hybrid systems, both off-road properties and unlimited continuous climbing capabilities are assured. With a maximum trailer load of up to 3.5 metric tons, the Touareg V6 TSI Hybrid can also be recommended as an ideal towing vehicle. Furthermore, the parallel hybrid approach offers a higher level of efficiency than alterne hybrid concepts in cross-country and freeway driving.
The powertrain itself primarily consists of the V6 TSI, the 8-speed automatic transmission that is also ideally suited for hybrid and tow vehicle use and the hybrid module integrated between the internal combustion engine and the automatic transmission. The latter weighs 55 kilograms. The compact module houses – in one unit – the disengagement clutch located after the V6 engine and the E-motor.
The interplay of components is "directed" by a hybrid manager. This multi-functional unit is integrated in the engine controller and communicates via the CAN bus lines with units such as the automatic transmission, high voltage battery and so-called power electronics that controls the electric motor. The latter also manages the energy flow between the electric motor and battery. Using the DC/DC converter, the power electronics also ensures that the car's 12V electrical system is supplied via the E-motor or the high voltage battery. Depending on the charge state of the battery (capacity: 6 Ah), vehicle speed and other vehicle-specific parameters, the hybrid manager automatically selects the ideal operating mode based on lightning fast analysis of all signals.
Nickel metal hydride battery in detail
The nickel metal-hydride battery used in the Touareg V6 TSI Hybrid reflects what is currently the best and most practical electric storage system for automobiles. Functional safety, robustness and cost are all factors that favor the high-performance NiMH battery.
The battery is located in a space saving area. On the prototype the cargo floor has been raised by 50 millimeters. The battery weighs 67 kilograms, consists of a total of 240 individual cells and therefore generates a voltage of 288 Volt. An additional duct integrated in the Touareg's interior ventilation system and two separate fans are used to keep the battery within an optimal temperature range. A battery manager continually monitors battery charge by coordinating data with the hybrid manager integrated in the engine controller.
Special power cables connect the battery to the power electronics – located to the left of the engine in the front of the vehicle – to supply the E-motor with energy or – in the reverse case – to charge the battery by E-motor while it acts as a generator when braking (regenerative braking) or by the V6 TSI (via load point shift). In the event of a crash, the high voltage battery is protected by what is known as a "Protect Box". The battery system, which includes the Protect Box, battery and ventilation components, weighs 79 kilograms.
Partial compensation for added weight of hybrid system
To compensate for a portion of the weight of the hybrid components (about 175 kilograms), the prototype exhibits numerous modifications compared to the production vehicle. One example is the full-time 4XMotion all-wheel drive. In today's Touareg, the drive is transferred to the front and rear axles via a transfer box which contains a lockable central differential and a two-speed range gearbox. On the Touareg V6 TSI Hybrid this is replaced by a lighter Torsen differential similar to the one Audi uses on the Q7. All the traditional capabilities of the Touareg are fully preserved, such as its optimal properties as a towing vehicle.
Other changes compared to the production Touareg
Various components have been redeveloped to retain all the traditional convenience and safety-related functions of the standard Touareg in the Touareg V6 TSI Hybrid. For example, the prototype has electro-hydraulic power steering, which does not have to rely on a servo pump driven by the internal combustion engine. In addition, a high voltage air conditioning compressor guarantees comfortable interior temperatures on the Touareg V6 TSI Hybrid, even when the V6 engine is switched off. Instead of an alternator, the DC/DC converter integrated in the power electronics ensures a constant supply of power to the vehicle electrical system.
The 8-speed automatic transmission was also specifically tuned for hybrid use. Among other things, it received a special torque converter with larger lock-up system, an auxiliary electric oil pump (to maintain a supply of oil when the V6 TSI is switched off), a transmission heater to reach optimal operating temperature faster, and a modified transmission controller.
Car is started by electric motor
The E-motor now takes over the role of engine starter motor. This job is especially challenging, since restarting of the V6 TSI must be executed with a high degree of smoothness and precision to maintain comfortable transitions between the various modes of propulsion. As soon as the engine is to be restarted, the transmission's lock-up torque converter is put in the "Slip" position and the E-motor's speed is increased to a setpoint value prescribed by the transmission controller. Only then does the engine controller receive an enable to actuate the disengagement clutch. The E-motor "drags up" the V6 TSI by subsequent engagement of the clutch and, as soon as the cylinders fill, the engine is started by enabling of injection and ignition. The E-motor's torque is increased by the amount of the momentary torque transferred by the disengagement clutch during the drag operation and – after the internal combustion engine has started – it is reduced again in response to the increase in engine torque. When positive engagement occurs at the disengagement clutch, the lock-up torque converter is engaged again. All of this sounds complicated, and it is complicated, but the system operates in such a way that the driver and occupants are completely unaware of its contribution to smooth progress. And that is just how things should be.
Passat BlueMotion: Here a common rail TDI (81 kW/110 PS) provides for 4.9 liter fuel consumption and CO2 emissions of just 128 g/km. The Passat BlueMotion (starting at 26,750 €) has a Start-Stop system and conforms to limits of the Euro-5 emissions standard. Its range of over 1,400 kilometers on one tank of fuel is a minor sensation – travelers starting out in Berlin will not be looking for a gas station until shortly before Rome. Naturally, the Passat BlueMotion will also be available as a wagon (starting at € 27,900).
Passat BlueTDI: Its 105-kW diesel is ahead of its times; that is because Volkswagen is introducing the first TDI to conform to limits of the Euro-6 emissions standard that does not take effect until 2014. Aboard the Passat BlueTDI (starting at € 29,225), a SCR catalytic converter reduces nitrogen oxides to less than 80 mg/km. Fuel economy of the sedan shifted by a 6-speed gearbox: 5.2 liter/100-km (CO2 emissions: 137 g/km). Further options: the "BlueTDI" will also be available as a wagon (starting at € 30,375), and it will be available with a 6-speed DSG.
Passat TSI EcoFuel: The Passat TSI EcoFuel is ushering in a new era of cars powered by natural gas. Until now, one of the drawbacks of cars powered by natural gas is that their performance can be rather unexciting. Thanks to its 110 kW strong high-tech engine, the Passat TSI EcoFuel combines a maximum speed of 210 km/h with excellent fuel economy and finally puts an end to these limitations. The car accelerates to 100 km/h in just 9.7 seconds. Despite its great agility, the world's first turbocharged and supercharged direct-injection engine configured for natural gas operation is satisfied with just 4.4 kilograms of natural gas, which is about € 4.25 per 100 kilometers. With a 7-speed DSG, the Passat breaks the magic CO2 limit of 120 g/km in this class (6-speed transmission: 4.5 kg/100-km and 123 g/km CO2). If the natural gas on board should run low before the next fill-up station, the engine controller switches over to gasoline mode. The car has a total range of more than 900 kilometers. The Passat TSI EcoFuel will be offered at a starting price of € 29,975; on the Wagon it is € 31,125.
All data and equipment contained in this press release apply to models offered in Germany. They may differ in other countries. All information is subject to change or correction.
TDI, TSI, DSG and Twincharger are registered trademarks of Volkswagen AG or other companies of the Volkswagen Group in Germany and other countries.