Fuel Cut Feature
#1
06-01-2009, 08:14 PM
Fuel Cut Feature
The following is from Ford about the new 2010 Fusion and one of its new features.
Aggressive Deceleration Fuel Shut-off. The 3.0-liter V-6 also regulates its gas consumption by using aggressive deceleration fuel shut-off for an efficiency improvement of approximately 1 percent. When the driver releases the accelerator pedal to slow down, the system temporarily turns off the fuel. The flow of fuel seamlessly resumes when the vehicle reaches a low speed or when the driver accelerates again. The system uses the transmission to keep the engine running at a low, more efficient operating point whenever possible. This system will be added to the 2.5-liter lineup later in the 2010 model year.
At a Ford Escape Hybrid Forum I read about this feature being used in the Ford Escape Hybrids. It was in a thread about using a ScanGuage-II and some of its setup options. I got a SG-II for other reasons. It seems when fuel cutoff is used the O2s and other sensor inputs are disabled by going into a Open Loop like with a cold engine or WOT.
Although I have a OBD-II scanner that could monitor the Loop Status I used the SG-II. Over about 40mph while coasting a '09 FE goes into Open Loop till you apply the brakes. Not sure if this is the same exact system that's going into the 2010 Fusion or not but it sure does a fuel cut of sorts.
There are times while coasting, I get back on the throttle and it almost feels like the engine died. I'm thinking that this is the fuel cut that I'm feeling and the transition isn't that perfectly seamless!
Aggressive Deceleration Fuel Shut-off. The 3.0-liter V-6 also regulates its gas consumption by using aggressive deceleration fuel shut-off for an efficiency improvement of approximately 1 percent. When the driver releases the accelerator pedal to slow down, the system temporarily turns off the fuel. The flow of fuel seamlessly resumes when the vehicle reaches a low speed or when the driver accelerates again. The system uses the transmission to keep the engine running at a low, more efficient operating point whenever possible. This system will be added to the 2.5-liter lineup later in the 2010 model year.
At a Ford Escape Hybrid Forum I read about this feature being used in the Ford Escape Hybrids. It was in a thread about using a ScanGuage-II and some of its setup options. I got a SG-II for other reasons. It seems when fuel cutoff is used the O2s and other sensor inputs are disabled by going into a Open Loop like with a cold engine or WOT.
Although I have a OBD-II scanner that could monitor the Loop Status I used the SG-II. Over about 40mph while coasting a '09 FE goes into Open Loop till you apply the brakes. Not sure if this is the same exact system that's going into the 2010 Fusion or not but it sure does a fuel cut of sorts.
There are times while coasting, I get back on the throttle and it almost feels like the engine died. I'm thinking that this is the fuel cut that I'm feeling and the transition isn't that perfectly seamless!
#2
06-02-2009, 09:44 PM
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a large number of vehicles have been doing this for years, they will shut off fuel to the injectors when you let off the accelerator at higher rpms and then re-introduce fuel at lower rpms. Ford must just be doing this in a more aggressive manner to save fuel even further than the usual way that it has been done in the past.
With my Ford Fusion and my Ford Escape I believe Ford also varies valve timing to provide less engine braking when you let off the accelerator completely. This is to provide greater coasting range with less drag from the engine compression. I think it re-engages to provide more engine braking when you get into lower rpms or try to use the brakes. That may be some of the rough transition that you are feeling when you go to use the accelerator again, it takes a brief second to make the change. The transmission is likely altered at the same time as well.
With my Ford Fusion and my Ford Escape I believe Ford also varies valve timing to provide less engine braking when you let off the accelerator completely. This is to provide greater coasting range with less drag from the engine compression. I think it re-engages to provide more engine braking when you get into lower rpms or try to use the brakes. That may be some of the rough transition that you are feeling when you go to use the accelerator again, it takes a brief second to make the change. The transmission is likely altered at the same time as well.
#3
06-02-2009, 10:40 PM
How much more aggressive can they get or are they rehashing old technology in this PR about the 2010 Fusion? I'm sure you notice that they don't advertise the Escape very much.
I'm not sure about this all now because here's a article that states that the 2009 Ford Flex is the first to use this fuel cut system: http://allworldcars.com/wordpress/?p=6162. More Googling shows this latest fuel cut system on many '09 Ford products. Patents from Ford date back into the late ninties, early systems had problems and the newer system are very complex!
I'm not sure about this all now because here's a article that states that the 2009 Ford Flex is the first to use this fuel cut system: http://allworldcars.com/wordpress/?p=6162. More Googling shows this latest fuel cut system on many '09 Ford products. Patents from Ford date back into the late ninties, early systems had problems and the newer system are very complex!
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