Volvo’s made a concept engine that produces 450 horsepower with just 4 cylinders. Volvo
Volvo’s long had a reputation for building safe, if boring, cars. But its Chinese owners have been pumping money into the place, leading to new cars, new engines, and new safety technologies that make Sweden sound like a new Silicon Valley.
The automaker burnished its rep with some cool safety and infotainment innovations in the flagship XC90, but it’s totally stunned us with the High Performance Drive E Powertrain Concept engine. That’s a really fancy way of saying absurdly powerful four-banger. Although Volvo’s concept displaces just 2.0 cylinders, it produces 450 horsepower. That’s 15 more than the 5.0-liter V8 in the new Ford Mustang GT. How’d the Swedes do it? They bolted three turbochargers—three!—on the thing.
For those of you who aren’t gearheads, turbochargers are a well-established way to boost power with an eye toward conserving fuel. Simply put, a turbo forces more air into the engine—resulting in more powerful combustion—using a fan turned by the car’s exhaust. The downside is they don’t work particularly well at low engine speeds, and it can take awhile (relatively speaking) for that fan to spool up, so you get what’s called turbo lag—that momentary pause between getting on the gas and feeling that additional thrust.
We’ve seen plenty of twin-turbos before. Volvo’s innovation is adding a third—third!—turbo. But this one doesn’t charge the engine. It charges the other turbos. It’s electric, hence the name “e-booster,” and sends air into the two conventional turbos to improve their performance below 3,300 RPM, filling out the torque curve and eliminating that pesky lag problem.
It’s very clever, but it’s just the start. Volvo’s also created a 48-volt electrical system, instead of the conventional 12-volt, to drive that e-turbo. The beefier electric system also will allow the automaker to improve electric power steering systems and stop/start technology, but that big step forward will take five to 10 years to fully introduce. That’s why the three—three!—turbo engine is still a concept.
Bright Future, Shiny Present
So although we have to wait for that firecracker of an engine, the engines Volvo’s building now are impressive in its own right. The program started in 2010, when Ford sold Volvo Cars (it bought the division in 1999) to Chinese auto conglomerate Geely. Ford promised to continue supplying engines, but said Volvo would need its own by 2015. Volvo engineers used that five-year reprieve to ponder the future of automotive drivetrains, and what they might do with piles of Chinese money and a clean sheet of paper.
First, Volvo studied how its customers truly drive. The outgoing XC90 SUV had a powerful V8. Volvo found its drivers rarely pushed the engine past 4,000 RPM, and even then it was largely for heavy acceleration like getting onto the highway or trying to get home by curfew. Because V8s do their best work near the top of the rev range, Volvo customers rarely experienced the engine’s peak torque or horsepower. They did, however, experience peak gas consumption. “When the customer drives with a very heavy powertrain,” says Michael Fleiss, Volvo’s vice president of powertrain, “they’re never using the sweet spot of the engine. Instead, it’s idling all the time, running in a very inefficient area of the engine maps.”
The third turbocharger in Volvo’s concept engine powers the other two. Volvo
To design cars that deliver the performance customers want and need, Volvo decided to abandon V8s and V6s entirely. Now it focuses on four-cylinder models that deliver far better fuel efficiency and match how normal people drive. A smaller engine lets Volvo “bring the sweet spot of efficiency more in the direction of where our customers are using the engine,” Fleiss says.
The 2015 XC90 is the first of this new generation of Volvos. It’s powered by a 2.0-liter four-cylinder engine with a turbocharger and a supercharger. (While the turbo works best when the engine’s already going, a supercharger forces in air with power generated by the engine itself, so increased boost is available from idle.) The supercharger runs from idle to 3,500 RPM. Above that, an integrated clutch disengages the supercharger, allowing the turbocharger to take over.
The result is an engine that delivers more power at both low and high revs, without downsides like turbo lag. The XC90 also comes with an optional plug-in hybrid component that boosts both fuel efficiency and performance, giving drivers some 400 combined horsepower, 320 of which come from the small gasoline engine.
The XC90 comes with the Drive-E, the first of a new generation of Volvo engines. Volvo
The XC90′s engine is the first of the new generation, which will roll out across the brand’s lineup in the next few years. Engineers designed eight engines—four gas, four diesel—that will share a common engine block design and modular parts that can be switched in and out Legos. That saves money, which Volvo says it’s invested in other things, like the giant touchscreen interface in the new XC90.
There is a downside to using turbo and superchargers, and electric motors: With more moving parts, there are more things to go wrong. Fleiss isn’t worried, though. “There is more technology in there,” he says, but “no issue at all with durability.” Every powertrain runs through the same tests as all Volvo engine systems have. We’ll have to wait and see on this one, but Volvo is known for producing robust powertrains, including the one in the 1966 P1800 that reached three million miles last year.
There’s more good stuff on the way, Fleiss says. Technology cribbed from Formula One racing, like advanced turbo-energy recovery systems, could be coming in the next decade or two. “First we need to understand if it’s really value for money, is it robust enough for car life and so on.”
Until then, we’ll settle for this new wave of super-small, super-powerful engines.
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