Sometimes you just never know where you'll dredge up technical details on vehicles that carmakers haven't yet launched.
Technology conferences can be a good source. Take, for instance, the Advanced Automotive Battery Conference (AABC) held last week in Pasadena, California.
A battery systems engineer from Audi laid out full details of the hybrid-electric drive system in the upcoming Audi Q5 Hybrid, a vehicle that has been described only at Audi technology seminars for invited audiences and hasn't officially been revealed to the public.
The only public sign of the 2012 Audi Q5 Hybrid so far, in fact, has been a video teaser. Despite rumors, Audi's first-ever hybrid was not unveiled at the 2010 Los Angeles Auto Show last November.
Instead, it will be launched in Europe this spring, probably at the Geneva Motor Show, and will go on sale in Europe and North America at the end of the year.
The Q5 Hybrid is the second generation of the Volkswagen Group's hybrid development efforts. The first generation produced the 2011 Volkswagen Touareg Hybrid and the 2011 Porsche Cayenne S Hybrid, based on larger crossovers than the mid-sized Q5.
While those vehicles used a 3.0-liter supercharged V-6 engine and a nickel-metal-hydride battery pack, the new Q5 Hybrid uses a smaller 208-horsepower, 2.0-liter direct-injected and turbocharged four-cylinder engine, along with the group's first-ever lithium-ion battery pack.
The 2.0-liter four is similar to the smaller of the two engines offered in U.S.-market Q5 models (the other is a 270-hp, 3.2-liter V-6). But Audi has adapted it to hybrid use by fitting electrically-driven ancillaries for such functions as power steering and air conditioning.
44-hp electric motor
Directly behind the engine is a 33-kilowatt (44-hp) motor-generator unit, followed by a 8-speed Tiptronic automatic transmission whose torque converter has been replaced with an oil pump. The engine coolant system also cools the electric motor.
The engine and transmission modifications ensure that all vehicle systems continue to function even when the engine switches off, either at rest or during periods of "gliding" when the car is propelled only on electricity under light load at speeds up to 62 miles per hour.
The maximum electric range of the Q5 Hybrid is slightly less than 2 miles, under the right combination of speed, load, and temperature conditions.
Less than 300 pounds more
With the 1.3-kilowatt-hour lithium-ion battery pack weighing in at just 77 pounds, the entire hybrid system adds less than 300 pounds to the weight of the base Q5.
The pack is air-cooled, but Audi has fitted the battery with its own air-conditioning system, which cools it far more quickly than forced-air cooling would.
Consumption on the European test cycle was 33.6 miles per gallon, though EPA ratings are likely to be lower due to differences in the tests. Audi's performance figures say the Q5 Hybrid does 0 to 62 mph in 7.1 seconds, with a top speed of 138 miles per hour.
Audi plans to offer a battery warranty of at least seven years, according to its presentation.