Last post on Oct 01, 2013 at 10:26 AM
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Ford Explorer, Ford Explorer Sport, Ford Explorer Sport Trac, Car Buying, SUV
#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.
#90 of 716 Re: 2011 Ford Explorer-Talk to Ford here! [nvbanker]
Feb 13, 2011 (6:12 am)
Ridgelines...??? Any more interesting input on the 2011 Exploer?
#91 of 716 Re: 2011 Ford Explorer-Talk to Ford here! [nvbanker]
Feb 13, 2011 (1:00 pm)
I'd be tempted, REALLY tempted, if it were R/awd or even just RWD alone. Maybe, in a pinch, even if it were SH-AWD
#92 of 716 Delay in delivery of 4 WD 2011 Ford Explorers
Feb 13, 2011 (3:26 pm)
What is the delay with the preordered 4WD 2011 Ford Explorers? We have been told for weeks that our preordered 2011 Ford Explorer is on a quality hold. Whats the problem that these vehicles are not being released for delivery?
#93 of 716 Re: Delay in delivery of 4 WD 2011 Ford Explorers [kay4147]
Feb 13, 2011 (4:16 pm)
I stopped by a local dealer today, and they have half a dozen or so on the the lot. Maybe the hold is something to do with a feature specific to your order?