|October 24, 2007
Audi metroproject quattro: Drivetrain
Characteristic Audi sportiness plus a whole new dimension in efficiency – it is all down to the novel combination of a state-of-the-art turbocharged FSI engine with an electric motor and innovative control electronics.
Under the bonnet of the Audi metroproject quattro sits a four-cylinder TFSI with a capacity of 1.4 litres and a turbocharger. This engine is an advanced version of the unit that made its series production debut in the Audi A3 only a few months ago. Whereas the 1.4 TFSI musters 92 kW (125 bhp) in the A3, it delivers 110 kW (150 bhp) at 5,500 rpm in the study. Its peak torque of 240 Nm is on tap over a broad rev band from 1,600 – 4,000 rpm.
The Audi engineers have long since proven the performance potential of turbocharged FSI technology, both on race tracks around the world and out on the road. Indeed, a jury of experts awarded the accolade of "Engine of the Year" to the 2.0 TFSI for the third year in succession in 2007.
The new 1.4 TFSI builds on this very same concept in order to maximise efficiency on the one hand and performance on the other. Multi-hole injectors result in very homogeneous mixture formation and extremely efficient combustion. This is also an effective means of helping to cut pollutant emissions.
The integrated turbocharger promises optimised responsiveness and even more harmonious torque build-up. 80 percent of peak torque can be summoned up from as low down as 1,250 rpm, in other words barely above idling speed. And despite its power, the 1.4 TFSI sets new benchmark standards in its class for its acoustic output too.
Front-wheel drive + rear-wheel drive = quattro
Power transmission to the front wheels is the task of the sporty Audi S-tronic Direct Shift Gearbox. It allows drivers to make lightning-fast gear changes, without a clutch pedal and without any interruption in the power flow. Gearshifts can also be fully automated if desired. If drivers wish to change gear manually, they can do so by using the shift paddles mounted on the steering wheel. Reverse and Park, meanwhile, are engaged using the shift lever knob on the centre console.
When running on the combustion engine alone, drive power is delivered to the study's front wheels. If it is being propelled purely by the electric motor, on the other hand, the vehicle is transformed into a rear-wheel-drive car. The 30 kW (41 bhp) electric motor transmits its power directly to the rear wheels; the differential compensates for any slip on one side.
When the two drive units are working in unison, however, the Audi metroproject is transformed into a genuine quattro and can count on all the benefits of four-wheel-drive system. This ensures that the high torque of 440 Newton metres in total – 240 Nm from the 1.4 TFSI plus an extra 200 Nm from the electric motor – is transformed into the required level of tractive power when accelerating.
Overrun, or the regeneration phase as it is known, is one of this vehicle concept’s most important instruments for optimising efficiency: the braking energy released during deceleration phases is transformed back into electrical energy instead of it being released as heat and wasted.
The Audi metroproject quattro can in principle run self-sufficiently, using mixed operation of the combustion engine and electric motor. Thanks to intelligent control of the two drive units, energy regeneration as well as the automatic start/stop facility, fuel consumption drops by around 16 percent compared to a vehicle running on the petrol engine alone. Although the components of the electric motor add around 70 kilograms to the overall weight, the study still only burns 4.9 litres of premium fuel per 100 km in mixed mode, while CO2 emissions average just 112 g/km.
Pure electrical operation over shorter distances, however, is a particularly attractive alternative offered by this vehicle that benefits the environment and the owner's wallet alike – all the more so considering that the performance achieved in this mode and the range of over 100 kilometres are perfectly satisfactory. "Refuelling" the Audi metroproject quattro from power sockets alone, therefore, produces an unequivocal result: even allowing for the relatively high domestic electricity costs in Germany, it is still possible to achieve a saving of around €6.50 for every 100 km – or 70 percent – compared to the price of premium fuel.
The equipment, data and prices stated here refer to the model range offered for sale in Germany. Subject to amendment; errors and omissions excepted.