Audi Straps Electric Compressor to Mild Hybrid System
Audi has added an electric compressor to reduce turbo lag to one its most powerful mild-hybrid SUV models.
The new SQ5 TDI and range-topping SQ5 TDI Vorsprung model will boast a 3.0 V6 TDI engine with 347PS, electrically powered compressor, classic turbocharger and 48V mild hybrid technology. This replaces the previous bi-turbo engine with a single turbo charger supported by the compressor that claims split-second response to throttle demands. Coupled with the cars’ mild hybrid electric powertrain, the mid-size SUVs claim a 0-62mph sprint time of just 5.1-seconds on the way to an electronically limited top speed of 155mph and CO2 output of as low as 172g/km.
Pulling power, too, is impressive with a huge 700 Nm (516.3 lb-ft) torque from as low as 2,500 rpm. Under WLTP test conditions Audi claims the cars will return up to 34.4mpg (28.6mpg US).
A 48-volt mild hybrid system is based on that already seen in the A6, A7 and A8 models and stores energy in a lithium-ion battery with an electrical capacity of 10 Ah located beneath the luggage compartment floor. An AC/DC converter connects the conventional 12-volt electrical system.
The carmaker says the biggest benefit of the electrically powered compressor is delivered at engine revs below 1,650rpm where the single turbo would struggle to provide sufficient boost. By placing the compressor in the air intake channel downstream of the intercooler and close to the engine, should the turbo boost be too low, the compressor’s 7kW electric motor will kick in accelerating the compressor wheel to 65,000 rpm in just 300 milliseconds and producing a boost pressure of 1.4 bar.
— Paul Myles is a seasoned automotive journalist based in London. Follow him on Twitter @Paulmyles_
