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Ford Explorer, Ford Explorer Sport, Ford Explorer Sport Trac, Car Buying, SUV
#80 of 716 Re: 2011 Ford Explorer [rew1225]
Feb 08, 2011 (8:21 am)
I wouldn't hold my breath were I you.
Even absent the rear drive capability this 2011 Ford Explorer is pretty LARGE and WEIGHTY for a derated/detuned I4 EcoBoost/twinForce Gas-Guzzling engine. Cruise FE, running in derated/detuned mode, is likely to be abysmal if not just plain HORRID.
On the other hand should Ford rethink(***) the design, make it truly and ECO-boost engine, it might still come up short on the HP/torque equation.
*** Maybe use a variable delay technique for intake valve closing, simulate the Atkinson engine mode. 12-15:1 compression ratio during cruise but 9-10:1 to accommodate BOOST at WOT.
Even at WOT and full BOOST the HP/torque numbers look too low for a beasty of this size and weight.
#81 of 716 Re: 2011 Ford Explorer [wwest]
Feb 08, 2011 (8:49 am)
Quite honestly, I am not really sure where you are coming from on some of your thoughts. Printed data shows an engine with 237 HP at 5500 RPM & 250 lb.-ft of torque in a range from 1700 to 4000 rpm. Gas mileage est. hwy of 27 to 28...city at 22 mpg. The ft. of torque of the V6 is rated at 255. I'm willing to wait it out for this engine introduction and then make my decision. Thanks for your input....
#82 of 716 Re: 2011 Ford Explorer [rew1225]
Feb 08, 2011 (1:28 pm)
Ford's published estimate for the 2.0L I4 turbo is 18 city, 26-27 hwy.
The Hyundai Sonata's N/A 2.4L I4 DFI 198HP engine with 11.3 CR gets 35 hwy.
That would mean, to me, that Ford's 2.0L I4 DFI were it N/A and with 11.3 CR should get hwy FE in the same range or even better.
2.0L vs 2.4L should improve FE by 15-20%...?
Then add the extra weight of the new EXplorer back in?
Back to 35MPG hwy.
How much HP does it take to move the new Explorer along briskly on level terrain at 70MPH...?
But the real bottom line is that while a N/A 2.0L DFI engine would provide absolutely STELLAR FE, it would not meet the acceleration criteria of the typical US buyer.
So why not have "both"..??
A 2.4L DFI I4 that runs in Otto N/A mode(***1) for low engine loads/loading, transitions into /Atkinson cycle mode(***2) for moderate engine loads/loading, and then transitions into Miller cycle mode(***3) for heavier (WOT) engine loads/loading, hard acceleration, say.
***1 Native/base compression ratio of ~15:1.
***2 Delayed intake valve closing, effective CR of 12:1.
*** 3 Wastegate closes and additional intake valve closing delay reduces effective non-boost CR to 10:1 to provide for intercooled BOOST
#83 of 716 Re: 2011 Ford Explorer [wwest]
Feb 09, 2011 (6:33 am)
Thanks for the reply. Acceleration criteria for the average buyer a good point; however, with the 250 lb.-ft of torque Ford is quoting supposedly will make it feel like a V6 when accelerating. Not sure why you chose the Sonata sedan comparison engine statistical numbers to the heavier Explorer SUV numbers. I will say you lost me on the "Otto/Atkinson/Miller" paragraph.
#84 of 716 Re: 2011 Ford Explorer [rew1225]
Feb 09, 2011 (9:38 am)
Wanted to compare a non-turbo DFI engine with Ford's turboed DFI. Not a lot of choices.
Otto cycle: With a low cylinder A/F charge fill, the higher the CR is, within reason, the better.
Atkinson cycle: Once the cylinder A/F charge level begins reaching the point wherein detonation, dieseling, is a threat then CR MUST be "effectively" reduced. Delaying the intake valve closing via e/VVT-i, thereby forcing a portion of the charge back into the intake manifold, will not only accomplish that but will also retain a fairly high engine efficiency.
Miller cycle: In order to accommodate intercooled BOOST the CR must now be reduced to something in the range of 10:1. Effective CR under boost will still be, can be, as high as 12:1.
The current RX450h V6 engine and I suppose the HH engine, uses e/VVT-i (Extended Variable Valve Timing w/Intelligence) for transitioning between modes. e/VVT-i is used to vary the intake valve closing timing delay to transition the engine from Otto cycle mode, 13:1 native/base compression ratio, into Atkinson cycle mode, 10:1 effective compression ratio, as the cylinder charge level rises.
The "problem" with an Atkinson cycle engine is that in return for the HIGH engine efficiency you loose PERFORMANCE/POWER. A 3.0L engine is effectively reduced to a ~2.4L engine. But you can return the POWER level to that of the 3.0L by simply transitioning the engine into Miller cycle mode, COMPRESS and COOL the charge that enters the combustion chamber.
#85 of 716 Re: 2011 Ford Explorer [rew1225]
Feb 09, 2011 (9:46 am)
"..supposedly will make it feel like a V6.."
Yes, granted, but...
In order to use intercooled boost to raise the "effective" compression ratio you MUST start with a LOW base/native compression ratio during OFF-BOOST operation. In Ford's case this is ~10:1, absolutely SUB-STANDARD for a DFI engine that can easily have a 12:1 CR.
The majority of highway operational time for this engine will be in detuned/derated mode. POOR FE relative to a non-turbo DFI engine.
I think I'd wait for a DFI V6 (puzzle as to why this isn't already available) and the F/awd system that I can easily convert to RWD with "part-time" 4WD capability
#86 of 716 Re: 2011 Ford Explorer [wwest]
Feb 10, 2011 (6:56 am)
Thanksfor taking the time to really give me a good education on engines, particularly as it relates to what F is doing (or not considering) to the announced I-4 2.0L turbocharged scheduled for introduction on the new 2011 Ford Explorer. I will continue waiting this out before making any decision. Again, your comments and insights are really helpful & I do appreciate it. RW
#87 of 716 Re: 2011 Ford Explorer [rew1225]
Feb 10, 2011 (8:25 am)
Hello rew1225. You may want to get additional information on the subject of engines as the views expressed by wwest are not consistent with the experience and knowlege of others who do have direct industry experience in this field. Best of luck too you.
#88 of 716 2011 Ford I-4 2.0L EcoBoost Engine
Feb 10, 2011 (8:50 am)
THanks for you comments. Please direct me to a site where I can see other comments as it relates to F's alternative eingine (2.0L I-4 EcoBoost)for the new 2011 Explorer. Again, appreciate your input on this subject...rw1225
#89 of 716 Re: 2011 Ford Explorer-Talk to Ford here! [wwest]
Feb 11, 2011 (4:43 pm)
Real truck guys don't drive Ridgelines..... Sorry, they just don't.