Audi to add 48-volt electrical system to its cars

audi-rs5-tdi-concept

Audi will be adding a 48-volt electrical system to its cars, with examples on how the 48-volt technology will be used in production cars to be revealed later.

“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.”

According to Audi, the 12-volt electrical systems found in all cars are at the 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 3 kW. 12-volt battery power is no longer capable of meeting the demands of new devices such as electric compressors for forced induction.

The 48-volt system that runs separate from the 12-volt system is a solution. A higher voltage means smaller cable cross-sections are needed; this translates into lighter cable harnesses with lower power dissipation. The 12-volt lead battery’s equivalent is a compact lithium?ion battery supplies 48 volts as the energy source during engine?off phases, with a DC/DC converter supplying the 12-volt system. This is paired to a new efficiency-optimized 10 kW alternator.

Systemuebersicht

A 48-volt electrical system was recently showcased with the Audi A6 TDI concept and RS5 TDI concept earlier this year. The concepts were fitted with an electrically-powered compressor for forced induction, which operates independently of the engine load.

In the concepts, an electric charger complements a normal exhaust gas turbocharger arranged in series. The electric charger’s turbine wheel is powered by a small 7 kW electric motor that can accelerate the compressor wheel up to maximum speed in just 250 milliseconds.

The electric compressor is downstream of the intercooler. At very low engine speeds with low exhaust gas energy at the turbocharger, the bypass valve closes and the air is routed to the electric compressor. This can be flexibly integrated into a variety of forced induction concepts.

The result is a 3.0 litre biturbo V6 that can do 385 horsepower and a peak torque of 750 Nm, which peaks from just 1,250 rpm. Boost pressure is available immediately after each change of gears thanks to the interplay between the electric and exhaust gas chargers.

Audi also says they’ve developed solutions to improve dynamic chassis control based on 48-volt technology as well, with applications in this field to showcased soon.

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Paul Tan

After dabbling for years in the IT industry, Paul Tan initially began this site as a general blog covering various topics of personal interest. With an increasing number of readers paying rapt attention to the motoring stories, one thing led to another and the rest, as they say, is history.

 

Comments

  • shawal on Aug 26, 2014 at 11:23 am

    Wow……
    German engineering at its zenith…..

    Shxjfnfosurhsigsixshd idie….technique <<- audi motto…. Or somethibg like dat

    Like or Dislike: Thumb up 1 Thumb down 2
    • Obviously (Member) on Aug 26, 2014 at 12:14 pm

      Vorsprung durch technik. Pretty cool. Sounds like it’ll jack up the cost even more but that’s why this is a premium brand. So, instead of using a supercharger which will leech the engine’s power, they employed an electric charger for low speeds. I wonder if one day they’ll do away with the turbocharger entirely and opt to rely solely on electric chargers. Electrochargers?

      Like or Dislike: Thumb up 4 Thumb down 0
      • Audi main objective is to eliminate turbo lag at low rev / rpm.. Audi found the best solution is using electric motor turbo turbine & control by Engine ECU but I’m very sure they also using synthetic or mineral oil to cold down the electric motor & turbine…

        Like or Dislike: Thumb up 1 Thumb down 0
      • I wouldn’t say it’s impossible but I think the turbo will still be using the exhaust gas to power it with the aid from the electric spool-er. Well, exhaust gas is free so why not keep it? :)

        Like or Dislike: Thumb up 1 Thumb down 0
        • shawal on Aug 26, 2014 at 7:14 pm

          Yep…its still uses exhaust gases to spin the turbine at higher rpms..
          But to eliminate turbo lag, the turbo will spool itself first using electric power

          Autocar tested the rs5 tdi…and they said the results were fantastic

          Like or Dislike: Thumb up 0 Thumb down 0
    • Hundred cds on Aug 27, 2014 at 8:04 am

      Dynamic thinking outside the box…bravo Audi!

      Like or Dislike: Thumb up 0 Thumb down 0
  • Ah Beng supporter on Aug 26, 2014 at 12:36 pm

    Add what also kena smoke from the GSC, sai hei (waste energy).

    Like or Dislike: Thumb up 0 Thumb down 7
  • kadajawi (Member) on Aug 26, 2014 at 12:55 pm

    A stronger battery… could this mean aircon even when the engine is off? It would certainly be nice. Maybe an automatic system that uses the battery for aircon until it gets depleted too much, then the engine turns on automatically in a mode that puts as much power as possible into the generator (the Toyota HSD would be perfect for this, since it can use all the power the engine creates to drive the generator to charge the batteries). That drives the aircon and charges the battery until it is, say, 80% full (to prolong battery life). Then the engine can turn off again.

    Save fuel and emissions while providing good comfort to passengers.

    Like or Dislike: Thumb up 2 Thumb down 0
    • Obviously (Member) on Aug 26, 2014 at 1:37 pm

      The line between hybrids and conventional ICE cars are getting blurred…

      I like the direction it is going in. While it may introduce needless complexity into what are already pretty complicated machines, one does not buy a premium German car for second-rate technology, even if it may be unreliable.

      Like or Dislike: Thumb up 1 Thumb down 0
  • gaviny on Aug 26, 2014 at 2:20 pm

    Audi by far has the most silent diesel engines

    Like or Dislike: Thumb up 0 Thumb down 0
  • Komissar on Aug 26, 2014 at 2:38 pm

    Basically replacing the 12V lead-type with a Li-Ion race car battery (size of handphone). Nothing new to motorsport, but definitely not yet explored into mass production cars yet.

    It’s still expensive tho. For luxury cars like Audi, maybe ppl might pay.

    Like or Dislike: Thumb up 2 Thumb down 0
    • 4G63T DSM on Aug 26, 2014 at 9:55 pm

      Yes, putting a LiON battery is one step forward but the quantum leap is the implementation of high voltage electrical systems. Modern cars have so much electronics that a regular 12V system just can’t keep up, pulling too much amps through wires. Higher voltages are simply more efficient to loss through resistance (same reason why you have high voltage transmission lines). The other issue they will probably look into is the way a standard car’s electrical system is grounded. Grounding to body is a sure fire (pun intended) way for reliability issues.

      What Audi is doing isn’t new… automakers have been trying to do this for the past 2 decades…and the only thing stopping them isn’t technology, it is legacy support.

      As the article already mentions, the benefits are finer and lighter wires (probably with less insulation as it doesn’t heat up as much) and more power hungry options like the aforementioned electric supercharger (or A/C) can be feasibly implemented.

      Like or Dislike: Thumb up 2 Thumb down 0
  • DrCooper on Aug 27, 2014 at 7:27 am

    As well I don’t deny on the efficiency eliminating turbo lag…I think using VGT is much much more effective than this complex system not to mentioned it’s also adding more weight to the car.

    Like or Dislike: Thumb up 0 Thumb down 0
 

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