The potential for saving energy is considerable: for example, an Audi A3 1.4 TFSI with manual gearbox in conjunction with the energy recovery function can save 0.3 litres of fuel per 100 kilometres – this is equivalent to a reduction in CO2 emissions of approximately 7 grams per kilometre. The system is automatically activated when the ignition is switched on. If the driver doesn’t want to use it, it can simply be switched off at the touch of a button.

This is how it works: brake the car down to a standstill, shift into neutral and release the clutch. The system now switches off the engine and signals this via an indicator lamp. Depress the clutch before continuing the journey – the engine now starts automatically and the indicator lamp goes out again.

The start-stop function only works when …

• the driver’s door and the bonnet are closed
• the driver is wearing a seat belt
• the vehicle has been driven at faster than 4 km/h before stopping
• the vehicle is not pulling a trailer

In some cases the engine will not be switched off, for instance when …

• the engine temperature is still too low
• the difference between the interior temperature and the temperature selected via the air conditioning system is still too great
• the outside temperature is very high or very low
• the windscreen is being de-iced
• the optional parking aid or the optional park assist is activated
• the battery charge is too low
• the steering wheel is at a sharp angle or is being turned
• reverse gear is engaged
• the road is steep

The engine is started automatically by the system when …

• the vehicle rolls forward
• the windscreen is being de-iced
• there is a large difference between the interior temperature and the temperature selected via the air conditioning system
• the brake pedal has been depressed several times in succession
• the battery charge is too low
• power consumption is too high