Big and green(ish): The Audi A8
Audi is launching a new TFSI engine in the A8
The model, mated to a V6 2.8 TSI good for 210 hp and 280 Nm of torque (about 206 lb-ft.) has a top speed (but only for German Autobahn) of 238 km/h (about 150 mph) and does 0 to 60 mph in 8.0 seconds. As per the green specs, sorry: 8.3 l/100 km as "standard consumption" (I guess EU's combined cycle) which are equivalent to 28 MPG. CO2 emissions are a respectable 199 CO2 g/km.
Just in sake of comparison, the Lexus 600h (UK specs) has a bigger 5.0l V8 engine that has 290 ponies under the hood and 520 Nm of torque (384 lb-ft) yet still runs with 9.3 l/100 km (25 MPG) and 219 CO2 g/km.
Lightweight materials, such as aluminium, are the key for the relatively low weight of the car (1690 kg or 3725 lb). Audi has also enhanced aerodynamics to reduce the air drag coeficient. The engine uses TSI direct injection of gasoline, plus variable lift (valvelift). According to Audi's definition "Valvelift uses sliding cam units mounted on the intake camshaft, which are moved by an electronic control mechanism. Depending on the engine power demand, the valves are opened wide or less wide as determined by the position of the cam units."
Related:
[Source: Audi]
Reader Comments (Page 1 of 1)
rgseidl 12:19PM (8/08/2007)
Few people in Europe buy a car as big as an Audi A8 with a petrol engine. Cars this big are for people who frequently drive long distances on the motorway. 50hp is probably all you need to cruise at 75mph, so a petrol engine will be throttling the intake all the time whereas a diesel will not.
With extreme hypermiling techniques, Jeremy Clarkson actually got an Audi A8 with a twin-turbo V8 (4.2L) from London to Edinburgh and back on a single tank of 19.8 gallons (imperial), which works out to 40.4 MPG (imperial).
http://www.youtube.com/watch?v=b7AKJAu3D30
http://www.youtube.com/watch?v=67JGUbM2kao
By contrast, ToMoCo's single-mode hybrid system does little to improve motorway cruising fuel economy - though it does help in traffic jams.
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MikeW 3:35PM (8/08/2007)
The HSD does improve mileage, there is no torque converter to spontaneosly unlock.
Did you see how much of a problem the hills were for Clarkson, that is where the battery packs would come in.
The only problem with a fixed range transmission, is over ~75mph, the IVT needs to convert the engine's power to electricity, and then shuffle it around, and then back to mechanical motion. (less efficient that just using gears) That is why the IVT in the GS450h & LS600h have dual ranges.
To maintain 75mph, you'd barely need more than 25hp.
Clarkson could have: killed the DRLs, covered the upper grill, attached covers over the rear wheels (leave the fronts for cooling, the Audi is still front heavy ~60/40) and possibly folded the passenger mirror in. (there might be a small drag optimization)
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