Call of the mild
HOW AUDI’S ‘HYBRID’ SYSTEM HELPS THE ECO CAUSE
AUDI A CALLS IT a mild hybrid, and while it doesn’t actually do anything about driving the A4s wheels, the system fitted to our test car is interesting from a technical point of view. It just doesn’t do that much. With a 1.2kWh battery under the boot floor (which is why there’s a can of repair-goop instead of a spare tyre), the A4 can recoup some braking energy and even switch the engine off to coast and harvest for up to about 10 seconds at a time. That allows the electric motor to which the battery is wired to spin the engine over faster when the stop-start function is making itself useful, with the grunt of 5kW rather than the normal, weedy starter-motor fitted to a conventional car. Perhaps the most innovative thing about the system is that it also makes use of the front-facing camera to know when the car in front has started to move in traffic and preps the A4 for blast-off.