Technical Spotlight: Volvo’s T6 Four-Cylinder
It’s both supercharged and turbochargedby Mark McNabb, on
Volvo might be best known for safety, but its recent advancements in powertrain technology might compete for recognition. The new T6 four-cylinder is a technological marvel that combines both turbocharging and supercharging to provide a powerful yet fuel efficient engine that pulls like a strong V-6 or mild V-8 while still achieving an EPA-estimated 31 mpg on the highway in the 4,037-pound, AWD luxury sedan known as the S90.
The T6 builds off the foundation laid in the turbocharged T5 four-cylinder, but adds the belt-driven, roots-style supercharger. This is no ordinary blower, though. It uses an electromagnetic clutch within the supercharger’s nose cone that automatically and seamlessly disengages the compressor screws from the belt drive when the engine revs beyond 3,500 rpm. The reason being – superchargers deliver power best at lower engine seeds, but loose grunt higher in the power band. That’s why Volvo employs both a styles of forced induction.
Unlike the supercharger that supplies instant boost down low, the turbocharger works best at higher engine speeds and takes a few milliseconds to make boost. Volvo engineers eliminate any turbo lag by allowing the turbo to begin generating boost at the supercharger is taken offline. The transfer of boost is so seamless the 2.0-liter four-cylinder doesn’t even feel like it employs such whiz-bang witchcraft. It just supplies smooth power at nearly every rpm.
Volvo’s technical specifications say the all-aluminum, direct-injected engine generates 316 horsepower at 5,700 rpm and 295 pound-feet of torque at 2,200 rpm. Variable valve timing on both intake and exhaust ports further help the cause, while more efficiency is squeezed from the T6 thanks to a variable pressure oil pump and electrically driven water pump. Helping keep temperatures in check is a double water jacket design within the cylinder head, allowing more coolant to flow around the ports.
Volvo calls the T6 a “high-feature” engine, but we’d say that’s a gross understatement. Wards Auto thought so too, awarding the T6 with a 10-Best Engine Award for 2016. Volvo S90 customers should note the T6 does require premium fuel, but in the grand scheme, seems like a fair tradeoff for such smooth power in every inch of its 6,500 rpm range. My experience so far has netted a 26.1 mpg combined average, which is above the 25-mpg estimate from the EPA. My tester is estimated to get 22 mpg in town. Not bad; not bad at all.
|Engine||In-line 4-cyl. supercharged and turbocharged|
|Horsepower||320 HP @ 5,700 RPM|
|Torque||295 LB-FT @ 2,200-5,400 RPM|
|0 to 100 km/h (62 mph)||5.9 seconds|
|Top Speed||250 km/h (155 mph)|
|Fuel consumption l/100 km (combined)||7.2|