Audi Planning To Upgrade Vehicle Electric System To 48 Volts

Audi has announced it will be adopting a 48-volt electrical system in its vehicles starting in the near future. The new high-power electrical system is said to give engineers the ability to make sportier, more efficient, and more convenient cars.

“We are using the full bandwidth of electrification in our drive principles strategy,” says Prof. Dr. Ulrich Hackenbert, a Member of the Board of Management for Technical Devel Devel opment at Audi. “Running part of the vehicle electrical system at 48 volts plays a central role in this. It enables us to make more energy available.”

We’ve already seen two examples of Audi vehicles with the 48-volt system; the RS5 TDI and A6 TDI concepts. Both cars are fitted with an electrically powered compressor that gives extra boost to the engine, helping eliminate turbo lag. The compressor is a separate system than the engine, so there is no parasitic loss.

Boosting power won’t be the only benefit. Audi says the upgraded electrical system will help boost advancements in dynamic chassis control systems.

The 48-volt system will even work while the main engine is powered off. A small bank of lithium-ion batteries will supply the juice. A DC/DC converter then integrates the standard, 12-volt electrical system. What’s more, the battery pack also works in conjunction with a new efficiency-optimized alternator, basically turning the vehicle into a mild hybrid system.

Audi says the new system can save owners 0.4 liters of fuel per 100 kilometers, or roughly 0.105 gallons over 62 miles.

Click past the jump to read more about the Audi RS5 TDI Concept

Why It Matters

Cars have been running on the 12-volt system since the 1950s and not much has changed. Introducing a new voltage into the automotive industry may help with developing better subsystems within vehicles such as infotainment, safety, and comfort accessories – or so says Audi. Only time will tell if this switch is permanent or just a passing fad.

Audi RS5 TDI Concept

Audi RS 5 TDI Concept

Press Release

Audi is to upgrade part of its vehicle electrical system from twelve to 48 volts. The move represents another technical building block for facilitating the integration of new automotive technologies while increasing the power and efficiency of its cars.

“We are using the full bandwidth of electrification in our drive principles strategy. Running part of the vehicle electrical system at 48 volts plays a central role in this,” commented Prof. Dr. Ulrich Hackenberg, Member of the Board of Management for Technical Development at Audi. “It enables us to make more energy available. That paves the way for new technologies with which we can make our cars more sporty, more efficient and more convenient to use.”

Audi recently showcased the scope of the 48‑volt electrical system with the technology demonstrators Audi A6 TDI concept and RS 5 TDI concept. Both models are fitted with an electrically powered compressor. This operates independently of the engine load and therefore fundamentally improves the acceleration performance. 48‑volt technology is moreover ideal for realizing convenience systems for dynamic chassis control. Audi will shortly be unveiling a variety of applications in this field.

Audi Planning To Upgrade Vehicle Electric System To 48 Volts

The current state of the art technology has taken 12‑volt electrical systems to their very limits. Especially at low temperatures, all the various static‑load consumers can account for the entire power generated by the alternator, which can deliver up to three kilowatts. The battery power is no longer capable of meeting the demands of new, dynamic‑load consumers such as high‑performance electric compressors.

The solution is a second subsidiary electrical system running at 48 volts, to complement the 12‑volt power supply. The higher voltage means smaller cable cross-sections are needed; this translates into lighter cable harnesses with lower power dissipation. The 48‑volt electrical system features new storage technologies and delivers much more power than the 12‑volt system with lead batteries. That makes it an important element of the Audi strategy of electrifying various stages of the drivetrain. The Group’s developers have already come up with a scalable platform concept, including a version that incorporates the electrically powered compressor.
In currently the highest development version, a compact lithium‑ion battery supplies 48 volts as the energy source during engine‑off phases; a DC/DC converter integrates the 12‑volt electrical system. The lithium‑ion battery operates in conjunction with a new, efficiency-optimized alternator that qualifies the drivetrain as a mild hybrid. Within this concept there are diverse ways of starting, controlling and deactivating the combustion engine as needed. The powerful alternator achieves an energy recovery output of ten kilowatts, far more than is possible at present. That adds up to a saving of up to ten grams of CO2 per kilometer (16.1 g/mi), equivalent to around 0.4 liters of fuel per 100 kilometers (62.1 miles).


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