Cylinder disabling V-10
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5th Wheeling
Joined: Dec 2008
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From: El Cerro Mission - LL
Cylinder disabling V-10
I have a 2004 F-250 SD with a Triton V-10. My question is .... Can with the new technology out there is there a possibility of a V-10 at cruise speed being able to disable 4 or 5 cylinders and still run with a fuel savings?
Anybody know how to get, find, or do this?
Anybody know how to get, find, or do this?
Posting Guru
Joined: Mar 2005
Posts: 2,060
Likes: 7
From: Burnsville, MN
We've had this discussion several times in the past, and in fact so has Ford.
The immediate problem is that unused cylinders create significant drag as they compress and exhaust air. The main solution to this is some type of variable valve timing, which the V10 doesn't have, although the 5.4 does.
There was even an article a few years ago quoting some Ford VP of development, where pursuing this was discussed, but they were only talking minimal mpg improvement, something like maybe only ten percent.
One fellow even went to far as to test drive his V10 after disabling half his cylinders, and reported no significant mpg improvement. I.e., not enough improvement to make it worth his while to experiment further.
The immediate problem is that unused cylinders create significant drag as they compress and exhaust air. The main solution to this is some type of variable valve timing, which the V10 doesn't have, although the 5.4 does.
There was even an article a few years ago quoting some Ford VP of development, where pursuing this was discussed, but they were only talking minimal mpg improvement, something like maybe only ten percent.
One fellow even went to far as to test drive his V10 after disabling half his cylinders, and reported no significant mpg improvement. I.e., not enough improvement to make it worth his while to experiment further.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
The problem with this type of idea is that setting it up to realize any significant fuel savings requires some tricky valve work.
With the traditional valvetrain you're still compressing and pumping air. This causes a huge parasitic loss that likely would negate any fuel savings you'd see from simply deactivating half the fuel injectors. The other cylinders would have to work harder simply to overcome the parasitic pumping losses of the other cylinders.
Other manufacturers that have a system for this address this in the valvetrain as well. Dodge's MDS has a system where they use oil pressure to effect a change in the valvetrain which causes the deactivated cylinders' valves to stay shut. Therefore the compressed air forces the piston back down again which negates much of the parasitic loss.
Unless you figured a system to hold the valves shut you'll never see any real gains by shutting off cylinders.
With the traditional valvetrain you're still compressing and pumping air. This causes a huge parasitic loss that likely would negate any fuel savings you'd see from simply deactivating half the fuel injectors. The other cylinders would have to work harder simply to overcome the parasitic pumping losses of the other cylinders.
Other manufacturers that have a system for this address this in the valvetrain as well. Dodge's MDS has a system where they use oil pressure to effect a change in the valvetrain which causes the deactivated cylinders' valves to stay shut. Therefore the compressed air forces the piston back down again which negates much of the parasitic loss.
Unless you figured a system to hold the valves shut you'll never see any real gains by shutting off cylinders.
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,678
From: Stephensville WI
Cadillac did it by a solenoid mechanism on the rocker arm, which either connected the valve stem to the rocker arm or disconnected it. A V-10 can't use that technology because of the overhead camshaft.
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