When it launched its new S80 luxury sedan in 2006, Volvo introduced an ultra-compact and efficient 3.2-L inline six-cylinder engine. With characteristic dedication to safety and functionality, Volvo engineered the 16 to fit transversely into the engine compartment, noting that a transverse configuration helps reduce the risk of engine penetration into the passenger compartment in the event of an impact, and also conserves body length to facilitate a roomier, more comfortable passenger
compartment. “Our objective was to reduce engine size, improve performance, and enhance occupant safety,” stated Lief Settergren, S80 Product Manager, Volvo Cars of North America.
Although one could argue that other auto manufacturers share Volvo’s dedication to safety and functionality, it would be difficult to find many examples that are backed up by a ransversely mounted in-line six-cylinder engine. While isolated cases of transversely mounted 16 engines do exist-Daewoo’s Magnus engine, for example-they are rather uncommon. Volvo achieved the 16 engine’s transverse orientation by streamlining the entire installation-engine, transmission, and ancillaries-into as compact a space as possible, and relocating all ancillaries except the alternator to the unused space above the gearbox. Ancillaries are still belt-driven, but overhead camshafts are now chain-driven. Both the chain and the belt are driven by gears at the rear end of the crankshaft, with the gears partially integrated into the engine block. The drive system is integrated into a small gearbox with an intermediate shaft inside the driveshaft. Different gears drive the two shafts, delivering one speed for the camshaft drive and a different speed for the ancillaries. The alternator, installed on the engine block, is directly driven off the same shaft that drives the ancillary belt. The crankshaft damper has also been moved inside the engine block, located at the front of the crankshaft.
To help the S80 meet the conflicting demands of fuel economy, environmental responsibility, and performance, the 16 incorporates cam profile switching, continuous variable valve timing, and a variable intake system. For performanceoriented drivers, an optional4.4-LV8 with all-wheel drive was also offered. Now, Volvo has expanded its options for satisfying those conflicting needs with the introduction of a slightly smaller, turbocharged six-cylinder engine. Modeled after the naturally aspirated 16, the new 3.0-L T6 engine uses the 16 block and cylinder head with different machining, manifolds, and other boltons. The new port-fuel-injected all-aluminum engine has a mass of 419 lb (190 kg) as shipped and 468lb (212.5 kg) as installed. As with any turbocharger, exhaust gases leaving the cylinders spin a turbine on the end of the turbo shaft, causing an impeller at the other end to force compressed air into the induction system.The compressed air effectively increases the
amount of oxygen available in the engine for the combustion process. The boost pressure is controlled by a traditional
wastegate on the compressor side. On the intake side, an electronically controlled dump valve helps reduce the ‘whoosh’
noise when the throttle is released, and allows for more precise boost control.
With twin-scroll technology, the T6 engine’s exhaust gases are divided into two outflows, half from three cylinders and half from the other three cylinders. An air-to-air intercooler helps improve volumetric efficiency through isochoric cooling. With the twin-scroll turbo, the T6 delivers strong low-end torque without the size, complexity, or cost of a large engine displacement or two separate turbochargers. With the addition of turbocharging, Volvo was able to downsize the new engine’s
displacement by 7.5% as compared to the normally aspirated 16. With bore and stroke measurements of 3.23 in (82 mm) and 3.67 in (93.2 mm), respecaei-tively, the T6′s bore-stroke ratio, 0.880, is nearly the same as the 16′s 0.875. The longer stroke, which makes both six-cylinder engines slightly undersquare, helps generate better low-end torque and better overall fuel efficiency. Turbocharged to 0.7 bar (10.1 psi), the T6 delivers 281 hp (210 kW) and 295 lb·ft (400 N·m), the latter over a wide range from 1500 to 4800 rpm. Specific power rating is 73.5 hp/L (54.8 kWIL) and the specific torque is 99.9 Ib ·ft/L (135.5 N·m/L). Introduced with the 2008 S80, the new 3.0-L turbocharged T6 is expected to be offered in other Volvo models in 2009.