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says a 3-cyl. engine with cylinder deactivation would consume at least 3% less fuel than the same engine without it, and the technology is less expensive than a hybrid powertrain.
Schaeffler wants to use roller finger followers for cylinder deactivation, even in 3-cyl. engines.
Modern cylinder deactivation has been around for about a decade in pushrod V-8s fromand , and has applied the fuel-saving technology to overhead-cam V-6s as well.
With today’s high-output turbocharged 4-cyl. engines capable of 300 hp, it’s conceivable many cars soon could ply American highways during light-load conditions drawing power from nothing but a pair of firing pistons, while the other two go along for the ride.
So if power densities continue climbing as expected and turbocharged 3-cyl. gasoline engines become as stout as some naturally aspirated 4-cyl. engines, then why not deactivate one of those three cylinders?
That’s a question powertrain technology supplierhas been fielding from an increasing number of automaker customers seeking creative ways to jack up their CAFE ratings.
Engineers at Germany-based, which has delivered the switchable valve lifters enabling and previous-generation GM cam-in-block V-8s to cut off air and fuel to half the cylinders, say they are helping customers develop three all-new 3-cyl. engines that will shut down one cylinder during certain conditions.
All the gasoline engines, intended for small cars, employ turbocharging and direct fuel injection.
If customer prototypes are available with these 3-cyl. engines using cylinder deactivation, David Kehr hasn’t driven them yet. Schaeffler’s manager of valvetrain systems is hoping to within six months.
Kehr says he is convinced there are certain conditions when a vehicle can get all the motivation it needs from two pistons pumping, thanks to recent advances in friction and weight reduction. It helps that automakers have been able to quell some of the unique noise and vibration challenges associated with 3-cyl. engines.
“It will make sense when the consumers don’t even know it’s there,” Kehr says of the technology. “To tell someone you’re going to do it, they’d probably have a lot of apprehension. But even with all the cylinder-deactivation applications that have hit the market, I would argue most people don’t even know it’s there.”
Chrysler was first to market 10 years ago this spring with its Multi-Displacement System on the Hemi V-8, narrowly ahead of GM’s Active Fuel Management technology on the small-block. Both automakers claim a fuel-economy gain of about 8%.
GM also used Schaeffler’s deactivation system on a 3.9L cam-in-block V-6 that appeared first in the Chevrolet Impala. But the system bowed out within a few years after its 2007 arrival because of modest fuel-economy gains.
With CAFE standards bearing down, a sense of urgency has forced automakers to consider options that seemed unthinkable not long ago.
Bob Zito, Schaeffler’s engineering director-engine components, says turbocharged direct-injection 3-cyl. engines soon will be capable of 180 hp.’s 1.0L EcoBoost, a 2014 Ward’s 10 Best Engines winner, produces 123 hp.