Audi S4 TDI with 48 Volt Mild-Hybrid-System
Both S models of the A4 family – the Audi S4 Sedan TDI (combined fuel consumption 6.3 – 6.2 l/100 km (37.3 - 37.9 US mpg)*; combined CO2 emissions 164 – 163 g/km (263.9 - 262.3 g/mi)* and the S4 Avant TDI (combined fuel consumption 6.3 l/100 km (37.3 US mpg)*; combined CO2 emissions 166 – 165 g/km (267.2 - 265.5 g/mi)* – are now equipped with a V6 diesel engine as a power package.
The 3.0 TDI combines hefty torque, smooth running and a long range and provides a power output of up to 255 kW (347 PS) and maximum torque of 700 Nm (516.3 lb-ft). It accelerates the S4 Sedan TDI from zero to 100 km/h (62.1 mph) in 4.8 seconds on the way to an electronically governed top speed of 250 km/h (155.3 mph). This combination of power, torque and efficiency makes the Audi S4 TDI unique in the segment.
The electric powered compressor delivers powerful drive-off performance and virtually seamless power buildup when accelerating. As such, it eliminates any turbo lag, providing instant responsiveness in all driving situations. The electric powered compressor is integrated into a new 48-volt main electrical system, which also incorporates the mild-hybrid system. This provides even more efficiency potential than the MHEV system in the 12-volt electrical system on the A4 models. In the S4 TDI this is the next expansion stage in which the mild-hybrid technology will be rolled out based on 48 volts. The 12-volt subsidiary electrical system is connected to the 48-volt main electrical system via a powerful DC/DC converter. For the first time a powerful 48-volt belt alternator starter is being used in the S4 TDI as the heart of the mild-hybrid system with a maximum recuperation power of up to 8 kW when braking.
A compact, air-cooled lithium-ion battery with a capacity of 0.5 kWh, which is located under the luggage compartment floor, acts as an energy management center. The mild-hybrid system on the S models has the potential to reduce customer fuel consumption by up to 0.4 liters per 100 kilometers.