The new Audi SQ7 TDI, new partner for the turbochargers - the electric powered compressor

With 320 kW (435 hp) and 900 Newton meters (663.8 lb-ft) of torque, the Audi SQ7 TDI is the most powerful diesel SUV on the market. It combines first-class performance with low consumption and maximum dynamics. A number of new technologies work in conjunction to make this possible.
“In many fields of technology, the Audi SQ7 TDI is at the head of its class,” said Dr. Stefan Knirsch, Audi Board Member for Technical Development. “Its newly developed V8 engine is the first in the world to use an electric powered compressor. This was made possible by the 48 volt electrical subsystem, which also provides the energy for the electromechanical active roll stabilization. With these innovations, the SQ7 TDI once again demonstrates Vorsprung durch Technik,” said the Audi Board Member.

Enormous power: 900 Newton meters and 320 kW (435 hp) 

The Audi SQ7 TDI sets new benchmarks with 320 kW (435 hp) and 900 Newton meters (663.8 lb-ft) of torque – the latter between 1,000 and 3,250 rpm. It accelerates like a sports car from 0 to 100 km/h (62.1 mph) in 4.8 seconds; top speed is 250 km/h (155.3 mph) (governed). In the NEDC, it consumes just 7.2 liters per 100 kilometers (32.7 US mpg), which corresponds to CO2 emissions of 189 grams per kilometer (304.2 g/mi). The new eight-speed tiptronic provides for fast and efficient gear changes. At higher speeds, it allows coasting in neutral.

The new 4.0 TDI produces its power from a displacement of 3,956 cc. The two turbochargers are activated selectively according to the sequential charging concept. This combines high efficiency with dynamic power development. Control is via the Audi valvelift system (AVS), which here is making its debut in a TDI. At low engine speeds, only one conventional turbocharger is active. As rpm increases, the AVS activates the second exhaust valve in each cylinder, which until then had been closed. This directs hot exhaust to the second turbocharger, activating it.

New partner for the turbochargers: the electric powered compressor

An electric powered compressor (EPC), in which a compact electric motor drives the turbine wheel, supports the turbocharger whenever it cannot draw enough energy from the exhaust flow. The big diesel engine thus develops its immense power spontaneously with no turbo lag. The electric powered compressor provides the engine with the boost pressure needed for the dynamic delivery of power in less than 250 milliseconds. Its compressor wheel spins up to 70,000 rpm. The power is therefore available immediately when the driver presses the accelerator, which is also very apparent when starting off. The power for the electric powered compressor comes from a 48 volt electrical subsystem, another innovation in the Audi SQ7 TDI. A compact lithium-ion battery stores the energy.

The new V8 TDI features new high-tech solutions in all areas. Its intake side is on the outside; the exhaust side with the two turbochargers are in the inner V. This layout provides for short gas paths and spontaneous response. The common-rail system generates up to 2,500 bars of injection pressure. More fuel enters the combustion chamber, increasing specific output while simultaneously reducing emissions at part load. Continuously variable thermal management and sophisticated measures in the crankshaft and camshaft drive reduce friction.

Largest range in the segment: the driver assistance systems

The range of driver assistance systems available in the Audi SQ7 TDI is extremely diverse – 24 solutions are dedicated to composed, relaxed driving and safety. The standard Audi pre sense city offers a predictive warning and emergency braking system for accident avoidance and the protection of pedestrians. The adaptive cruise control maintains the interval to the car ahead at speeds between 0 and 250 km/h (155.3 mph).

In slow-moving traffic on well-paved roads, the traffic jam assist relieves the driver by temporarily taking over the steering in many situations. The predictive efficiency assistant uses precise information from the immediate vicinity for consumption-optimized driving. Other top innovations are the turn assist, park assist, exit warning and cross traffic assist rear.