When driving on the highway or freeway, a constant, moderate speed is more efficient and
economical than constantly accelerating and braking. Usually you can reach your destination just as
quickly by driving at a moderate, but steady speed.
The cruise control system can assist in maintaining a uniform driving style.
Moderate use of extra electrical loads
Comfort inside the vehicle is nice and important, but it is important to use them in an environmentally
conscious manner.
Some devices can increase fuel consumption when activated (examples):
x Climate control system (air conditioner): If the climate control system has to produce starkly
contrasting temperatures, it requires a large amount of energy, which is generated by the engine. The
temperature in the vehicle should therefore not be extremely different from that of the outside
temperature. It may be helpful to ventilate the vehicle before driving and then to drive a short distance
with the windows open. After that, switch on the air conditioner with the windows closed. Keep the
windows closed when driving at high speeds. Open windows increase fuel consumption.
x Switch off seat heating once it has served its purpose.
x Switch off the windshield and rear window defroster as soon as the windows are free of fog and
ice.
Additional factors that increase fuel consumption (examples):
x Malfunctioning engine control.
x Driving in the mountains.
x Towing a trailer.
Fuel-efficient driving
Fig. 249 Fuel consumption at 2 different outside air temperatures.
Driving
situations Requirements and conditions Vehicle behavior
– CAReful use of E-MODE button
⇒ fig. 251.
The high-voltage battery discharges quickly
with the E-MODE button switched on. This
can increase fuel consumption since driving
in electric mode is preferred in this case,
even though the combustion engine would
be more efficient.
Driving on
country roads
and highways.
– Conscious easing off of the
accelerator, to enable longer sailing
distance.
By easing off the accelerator, the
combustion engine is automatically
switched off and de-clutched. The vehicle
glides without engine power.
- Reducing speed by easing off the
accelerator early and not by
braking.
Sailing possible. Reduction of speed this
way is more fuel-efficient than through
braking.
- Avoid speeds of over about 160
km/h (99 mph).
Efficient sailing is possible with a speed of
about 160 km/h (99 mph) .
- CAReful selection of gear (S).
Sporty driving style with activated sport
programme increases fuel consumption.
Efficient sailing in sport programme with
combustion engine automatically switched
off is possible with a speed of about 70
km/h (43 mph).
Driving in cold
months.
- Do not warm up the combustion
engine by running it with the
vehicle stationary.
The temperature of the combustion engine
increases very slowly, but fuel consumption
increases considerably.
– CAReful use of heating for
windshield and the rear window,
outside mirror, seat and steering
wheel.
This prevents energy from being lost and
saves energy for the electric motor.
- Never leave the vehicle in a
garage over night.
This prevents the high-voltage battery and
the vehicle interior from cooling down too
much. The optimal temperature of the high-
voltage battery is reached quicker at the
beginning of the journey and the
combustion engine can be switched off
quicker when the vehicle interior is
sufficiently heated.