Mercedes-Benz to market S 400 BlueHYBRID next year

Steering and climatic comfort remain unchanged, as both the steering servo pump and the refrigerant compressor are electrically powered. Both systems therefore continue to operate even when the vehicle is at a standstill with the engine automatically switched off. The intelligent control logic is able to detect whether the driver is executing a turning or parking manoeuvre. In this case the automatic start/stop function is temporarily deactivated, so that these manoeuvres can be carried out in comfort.

Every braking action generates electric power for the battery

When the vehicle is braked, the electric motor acts as a generator and uses a process known as recuperation to convert the kinetic energy into electrical energy. This energy is stored in the compact yet highly efficient lithium-ion battery, and made available when required.

In the process the electric motor assists the engine braking effect of the internal combustion engine in two smooth, seamless stages: In stage one, on the overrun with no braking action, the electric motor acts as a generator and begins to recuperate energy. Stage two commences as soon as the driver lightly operates the brake pedal: the generator output is then increased proportionally, and perceived as heavier deceleration by the driver. Only when more brake pedal pressure is applied are the wheel brakes activated in addition to recuperation. In this way more electrical energy can be generated, while saving wear and tear on the hydraulic braking system at the same time. To make the best possible use of this double benefit, Mercedes engineers also developed a new braking system with a new brake pedal module for the S 400 BlueHYBRID.

Cleverly located control electronics

Dedicated control electronics are required to operate the 3-phase AC electric motor in the 120-Volt high-voltage DC network. The current converter is accommodated in the space formerly occupied by the starter. As the control electronics heat up as a result of electric currents measuring up to 150 amps, the system is equipped with its own, additional low-temperature cooling circuit.

Mercedes-Benz engineers have accommodated the transformer in the right front wheel arch, where it facilitates the exchange of energy between the 120-Volt high-voltage network and the 12-Volt onboard network – and also allows the option of emergency starting with jump leads if the standard battery should lose its charge. To ensure a consistently high level of electrical efficiency, the transformer is likewise cooled by a low-temperature circuit. The 12-Volt lead/acid battery is installed in the boot, and not only supplies the standard consumers but also the monitoring system for the high-voltage components with energy. Thanks to its interaction with the lithium-ion battery, it is considerably smaller in size and lighter than usual.

Tried-and-tested automatic transmission with a new configuration

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