Explorer concept’s new engine offers greener future.
2008 Ford Explorer America Concept |
Automotive engineering is all about trade-offs. You want to build something bigger, you normally wind up with more weight. More features? A higher price tag. To improve performance, meanwhile, you sacrifice fuel economy and emissions. At least that's the traditional equation.
With its EcoBoost technology, however, Ford engineers apparently are adopting new math. An array of new engines will not only boost power but increase mileage while also reducing harmful emissions. The technology will make its formal debut at this month's Detroit auto show. More significantly, the automaker plans to begin rolling EcoBoost out on a half-million Fords, Lincolns, and Mercurys annually over the next five years.
EcoBoost actually isn't an entirely new technology, at least not to Europeans, who are already familiar with the concept of direct injection technology. It's also been starting to show up in the U.S., where Cadillac offers a DI 3.6-liter V-6 option for its 2008 CTS sedan. But pairing direct injection with turbocharging is a significant advantage, nonetheless.
Some engineering basics might be helpful here. In a gasoline-powered engine, fuel and air are mixed together prior to being pumped into each cylinder's combustion chamber. Then the volatile blend is compressed and ignited, providing the power that eventually turns the car's wheels. In a DI engine, air is drawn into the cylinder on its own, and only after the intake valve is closed, is a shot of fuel squirted into the combustion chamber through special injectors.
EcoBoost adds another touch, by turbocharging - pre-compressing - the air before it goes into the cylinder. That's a traditional formula for improving performance. But normally, it has its downsides, notably something called turbo lag. You might have experienced this when stomping on the accelerator of a turbocharged car: a brief hesitation at launch, followed by a sudden and sometimes disconcerting burst of power.
Ford's Dan Kapp, director of powertrain research, and overseer of the EcoBoost project, says the new technology "effectively eliminates turbo lag," while still delivering the performance boost turbochargers are capable of producing.
Take the 3.5-liter V-6 EcoBoost engine, which will reach market later this year on the new Lincoln MKS. It will produce 340 horsepower and 350 pound-feet of torque. A more conventional Ford 3.5-liter V-6 makes just 265 horsepower.
There are two ways to use EcoBoost technology, which is also known as gasoline turbo direct injection, or GTDI. It can be used as a performance feature, much like Cadillac is using its (non-turbocharged) direct-injection engine in the CTS.
Ford will take a very different approach. Think of EcoBoost, says Kapp, "as a small engine that thinks big." In times past, Ford might have gone with a V-8 for its new MKS, which will be the first production use of the direct injection system. When you want performance, there's plenty of power, Kapp continues, but under normal driving conditions, you'll get the mileage of a V-6, in this case, about a 20-percent gain over the comparable V-8.
Ford has so far developed two versions of EcoBoost, the 3.5-liter V-6 as well as a small in-line four pumping out 275 hp and 280 lb-ft of torque, about what you'd normally expect from a beefier six-cylinder.
Ford isn't the only automaker looking for ways to deliver the holy grail of better mileage, performance, and emissions. And pressure on manufacturers will only increase now that federal lawmakers have agreed to a sharp increase in the Corporate Average Fuel Economy, or CAFE, standards. But many of these solutions are complex and costly and generate relatively meager gains in mileage.
There are, of course, added costs to going with both turbocharging and direct injection, acknowledges Ford's Kapp. But they're offset by being able to utilize a smaller engine: a V-6 instead of a V-8, a four-cylinder instead of a six-cylinder. On top of that, EcoBoost is largely based on existing conventional Ford powertrain hardware. The block for the two 3.5-liter V-6s are, for example, the same.
In the future, Kapp notes, it would be possible to develop completely unique EcoBoost engines. A more rugged block, for example, might allow even more turbo boosting, and thus generate more power. But for now, Ford believes it has a cost-effective formula that will deliver what consumers want - and tough new mileage regulations require.
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