Audi Debuts Three New Engines for A3 Hatchback

Volkswagen AG's Audi unit has unveiled a trio of new turbocharged four-cylinder engines that are more powerful and efficient than the powerplants they replace. The engines will debut in the brand's redesigned A3 small car in September.

The lineup starts with a 2.0-liter diesel rated at 150 hp and 236 lb-ft of torque. Audi says it achieved a 7% improvement in fuel efficiency by adding a two-stage oil pump, low-friction balance shaft bearings, active cylinder block cooling and "elaborate" needle bearings for the drive wheels of the two camshafts.

The new diesel consumes 4.1 liters of fuel per 100 km (57 mpg) and emits 106 g/km (57.4 g/mile) of carbon dioxide. Audi says the mill can push the A3 from zero to 100 kph in 8.6 seconds.

The second new engine is a 1.4-liter gasoline unit that makes 122 hp and 148 lb-ft of torque. The powerplant, which is about 9% more efficient than the unit it replaces, consumes 5.2 liters per 100 km (45 mpg) and emits 120 grams of carbon dioxide per kilometer (193 g/mile). Design improvements include integrating the exhaust manifold into the cylinder head, reducing turbocharger weight by 4 lbs and using a toothed timing belt designed to last the life of the engine. Audi says engine friction losses were cut 20% compared with the previous engine.

The company plans to later add a variant of the 1.4-liter engine rated at 140 hp and 184 lb-ft of torque and equipped with Audi's "cylinder on demand" system. The technology varies the valve stroke for the second and third cylinders and can shut down both cylinders entirely during coastdown. The system stops the valves in the closed position during light-load conditions and can reactivate them in as little as 13 milliseconds when the accelerator is pressed.

Audi says the transition between two- and four-cylinder operation is smoothed by adjusting fuel injection, ignition timing and throttle valve position. The cutoff system functions across a range from 19 mph in third gear to 81 mph in fifth or sixth gear.

Audi's third engine is the most powerful of the trio. The 1.8-liter gasoline unit produces 180 hp and can deliver 184 lb-ft of torque at speeds as low as 1,250 rpm. The engine boosts the A3 from zero to 100 kph in 7.2 seconds and to a top speed of 144 mph, according to Audi. CO₂ emissions are 130 g/km (209 g/mile).

Like the 1.4-liter engine, the larger four-banger is equipped with direct gasoline injection. But the system operates only during startup and when engine loads are relatively high. Under light-load conditions, secondary injectors feed fuel into the induction tubes ahead of the intake valves. Audi says the dual-injection system reduces particulate emissions and boosts fuel economy about 13%.

Audi says it will add several other engines and powertrain configurations over the next year or two. First up for the European A3 will be a 1.6-liter diesel rated at 105 hp. The four-cylinder powerplant consumes only 3.8 liters per 100 km (62 mpg) of fuel, emitting 99 g/km (159 g/mi) of CO₂.

Other upcoming engines will include a more powerful S-model unit and a super-efficient 110-hp powerplant that burns natural gas and emits only 30 g/km (48 g/mi) of CO₂. Audi says electric and hybrid powertrains also are under development for the A3.