The technology inside the Mercedes-Benz S 400
of sustainable mobility. It’s the world’s first series-produced passenger car fitted with a 120-volt
lithium-ion battery.
Our pleasurable canter through time and space is underpinned by a modified version of the 3.5-liter engine from the S 350 producing 205 kW/279 hp.
The 6-cylinder unit is backed up by a disc-shaped electric motor developing an additional
15 kW/20 hp. The electric motor can send up to another 160 Nm
of torque to the crankshaft of the internal combustion engine when the driver presses down fully on the accelerator. The engine has barely reached its idling speed of 690 rpm by the time the internal combustion engine and electric motor have together drummed up 385 Nm of torque. A glance at the fuel consumption display confirms our suspicions: the electric motor also helps to save fuel, especially over inter-urban routes. The 3-phase AC external rotor magneto motor backs up the main engine in response to changes in parameters such as engine speed and accelerator position, and transfers a carefully calculated portion
of power to the crankshaft. If green arrows lighting up
in the display instead of red indicate that the electric motor is in generator mode, recovering kinetic energy
– like a bicycle dynamo – through a process known
as recuperation.
Lift your right foot and let the car coast, and the battery’s charge display will continue on towards the maximum end of the scale. The figures tick over even faster under light braking, which ups the output of the generator and prompts the electric motor to increase the braking effect of the internal combustion engine. The disc brakes are only employed if the driver wants to decelerate more quickly and increases pressure on the brake pedal. The recuperated energy is stored in a
grated installation inside the cooling circuit of the air conditioning system. All in all, the battery technology in the S 400 HYBRID represents a milestone along
the road to the mobility of tomorrow. A high-voltage lithium-ion battery already provides the key to efficiency in the Mercedes-Benz S 400 HYBRID. As well as supplying the electric motor with power, it is also connected to the luxury sedan’s 12-volt on-board power supply via a DC transformer. The transformer allows the standard consumers such as the vehicle’s headlamps and power windows to be supplied via
the high-tech battery.
The highly complex control electronics do their work behind the scenes, but their efforts certainly do not go unnoticed at the pumps. Using the 120-volt battery
to supply power to the low-voltage on-board supply means less work for the alternator of the internal combustion engine and thus lower fuel consumption. The S 400 HYBRID also has a trick up its sleeve
when it comes to the irregular conditions of down-
town driving. The ECO start/stop function switches the internal combustion engine off as soon as the brakes are activated and the car’s speed falls below
15 km/h (9 mph).
When the traffic starts to move again, all the driver needs to do is release the brakes - the electric motor restarts the main engine simultaneously with the movement of the driver’s foot.