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2012 Ford Explorer

EcoBoost 2.0-liter four-cylinder  (Source: Dana60Cummins/Wikipedia)
The new EcoBoost engine option gives up 40 hp to the V6, but betters it in low-end torque and fuel efficiency

With rising gas prices and the government's keen eye on CAFE numbers, more and more fuel efficient vehicles are starting to flood the market. Turbocharging was once relegated to performance cars and diesels, but now manufacturers are starting to adopt the direct injection and turbocharging for their mainstream gasoline engine vehicles. Hyundai has found success by replacing its V6 engine on the Sonata with a 274 hp turbocharged inline-4. Likewise, Ford has found success with its EcoBoost V6 engines in the Taurus SHO, Flex, and F-150. 

Now, Ford is bringing a new 2.0-liter EcoBoost four-cylinder to the recently revamped Explorer crossover. While the Explorer is currently available with a naturally aspirated 3.5-liter V6 that produces 283 hp (@6,500 rpm) and 252 lb-ft of torque (@4,100 rpm), the new EcoBoost generated 240 hp (@5,500 rpm) and 272 lb-ft of torque (3,000 rpm). The new engine is paired with a 6-speed automatic transmission and is only available with front-wheel drive models. 

Many people would likely give up the 40 horses for the added low-end grunt and the fuel economy increase. The V6 is rated at 17/25/20 (city/highway/combined) while the new EcoBoost four-cylinder is rated at 20/28/25. Ford says that these numbers better segment rivals like the Toyota Highlander and the Honda Pilot.

Much like the EcoBoost V6 engine option (which is more expensive than the 5.0-liter V8), the EcoBoost four-cylinder in the Explorer will command a $995 price premium versus the V6.

"Today's SUV buyers place a high priority on miles per gallon, so Explorer has expanded its portfolio of fuel-efficient engines with an all-new EcoBoost offering," said Amy Marentic, Ford group marketing manager. "SUV buyers deserve efficiency with their capability, so Explorer now offers best-in-class V6 and four-cylinder fuel efficiency." 

Ford has seen the sales of its V6-equipped F-150s eclipse those of the larger V8 engines as buyers flock to power and fuel economy -- the company is hoping that that same formula works for the Explorer which has already sold more units in the first six months of 2011 than the old model did in all of 2010. 

Ford is also bringing an EcoBoost three-cylinder engine to its subcompact Fiesta.



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RE: Is it worth it?
By Brandon Hill (blog) on 7/28/2011 11:07:20 AM , Rating: 2
I guess it depends. If people trade in every five years, that is a $3375 savings. That's a lot of beer money :)


RE: Is it worth it?
By Solandri on 7/28/2011 3:04:32 PM , Rating: 4
Not so fast. There's something wrong with those mileage numbers. It says 17/25/20 city/hwy/combined for one engine, 20/28/25 for the other. The difference between city mileage (17 vs 20) is 3 mpg. The difference between highway mileage (25 vs 28) is 3 mpg. Yet somehow the difference between their combined mileage is 5 mpg? That doesn't make sense. There's no algebraic combination of A*city + B*hwy which can give you combined ratings of 20 and 25.

If 17/25/20 is correct, then the weighting to get the combined mileage is A=53%, B=47%. You drive 53 miles at 17 mpg (3.11 gal), 47 miles at 25 mpg (1.88 gal), for a total of 5.00 gallons over 100 miles, or 20 mpg.

But if you apply A=53%, B=47% to 20/28/25, you get 53 miles at 20 mpg (2.65 gal), 47 miles at 28 mpg (1.68 gal), for a total of 4.33 gal over 100 miles, or 23 mpg.

If 20/28/25 is correct, then the weighting for combined mileage is A=30%, B=70%. The 4-cyl engine gets 25 mpg combined. The 6-cyl engine gets 22 mpg. I'll assume this is the correct figure since A and B work out to be round numbers.

So re-doing the annual fuel cost savings, we get:

@18k miles/yr
22 mpg for 1 year = 900 gallons * 3.75/gal = $3068
25 mpg for 1 year = 720 gallons * 3.75/gal = $2700
$368 savings, 2.7 year payback

@12k miles/yr
22 mpg for 1 year = 900 gallons * 3.75/gal = $2045
25 mpg for 1 year = 720 gallons * 3.75/gal = $1800
$245 savings, 4.1 year payback


RE: Is it worth it?
By Solandri on 7/28/2011 3:08:26 PM , Rating: 3
Whoops, forgot to change the gallons used numbers. But the $ amounts are correct.

18k miles/yr @ 22 mpg = 818 gallons

12k miles/yr @ 22 mpg = 545 gallons
12k miles/yr @ 25 mpg = 480 gallons


RE: Is it worth it?
By Stiggalicious on 7/28/2011 3:25:10 PM , Rating: 1
The EPA's numbers are still quite plausible, actually.

When you completely change the engine dynamics for a car, the mileage dynamics also change.
Sure, the minimum mileage can change by only 3, and the maximum can change by only 3, but the change in engine can also cause its mixed mileage to shift more towards highway mileage. Turbocharged engines usually do that since they're more efficient while delivering a higher amount of power than while delivering a lower amount. If you notice that the peak power/torques are also at lower RPMs, that means it's working closer to its peak efficiency more of the time.

To help visualize, enjoy this simple, er, visualization. The bars are city/highway, and the * is mixed.
V6:
| * |
Ecoboost:
| * |

It's still quite valid that the mixed mileage can shift more than both the minimum and maximum.


RE: Is it worth it?
By Solandri on 7/28/2011 4:02:55 PM , Rating: 5
quote:
Sure, the minimum mileage can change by only 3, and the maximum can change by only 3, but the change in engine can also cause its mixed mileage to shift more towards highway mileage.

Nope, the "EPA combined" mpg is just a straight algebraic combination of their measured city and hwy mileage. I finally found it:
http://www.epa.gov/fueleconomy/420f04053.htm#calc

It's just 55% city, 45% hwy. So the correct figures would be 17/25/20 and 20/28/23.


RE: Is it worth it?
By tastyratz on 7/29/2011 10:31:35 AM , Rating: 2
I think you are close but not quite. Turbocharged engines are more *mechanically* efficient by utilizing losses, but they are not more *fuel* efficient making the same power at 100% engine output. Don't forget the turbocharger is not a free lunch, while it uses waste exhaust gas energy to spin it does so by placing a restriction in the exhaust and in off boost in the intake as well. This piled on the fact that you need less efficient air fuel ratios and timing to support a denser charge per liter lead to less fuel efficiency. Anytime you are in boost to get max power, you use more fuel than another engine of equal power NA uses.
Generally NA engines have a bsfc of .50 at peak, turbocharged might be .60.

Also overall fuel efficiency for light driving in a non stressed turbo engine that is not making boost will be better because it is a smaller engine I am totally on board with that.


RE: Is it worth it?
By Spuke on 7/29/2011 11:09:05 AM , Rating: 2
quote:
This piled on the fact that you need less efficient air fuel ratios and timing to support a denser charge per liter lead to less fuel efficiency.
How does this change on direct injected engines?


RE: Is it worth it?
By tastyratz on 7/29/2011 4:01:44 PM , Rating: 2
direct injection allows for a more precise mixture and flexibility, but you can't get away from needing a richer mixture under power for engine safety/reliability. the biggest benefit I think of direct injection is the precision control of the injection event relative to crank angle. This allows full flexibility and leaner cruising mixtures. high pressure turbocharged events benefit from the better atomization so you can run a leaner mixture than before per say, but it still needs richer at wot compared to a similar NA engine


RE: Is it worth it?
By Spuke on 7/29/2011 6:25:00 PM , Rating: 2
quote:
but it still needs richer at wot compared to a similar NA engine
Thanks for the explanation.


RE: Is it worth it?
By JediJeb on 7/29/2011 5:00:31 PM , Rating: 2
Where fuel efficiency increases come in relative to turbo versus NA engines is that with the increased torque you can get away with a higher gear ratio so you travel farther per revolution of the engine. It is a trick that some people are using when putting the 4 cylinder Cummins (Bread Truck) engines in vehicles. They crank up the boost and the fuel injectors which should be using more fuel, but they also put in crazy high gear ratios and get better fuel efficiency in the end.

Same reason I can get fair mileage from my F150, because I can run in 5th gear at 30 mph or lower. Even in town I can do a quick 1,3,5 shift and be in overdrive for most of the distance between stoplights. It isn't as easy to get away with that in the V8 5.0L trucks because their torque curve maxes out at much higher rpm than my I6 4.9L.


RE: Is it worth it?
By Philippine Mango on 7/29/2011 12:21:19 AM , Rating: 2
The actual equation the EPA uses is 45% highway driving 55% city driving but thanks to your math, you came close. Just an FYI


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