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Save Gas - Simple Technique


GaryG

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Pulse and Glide (P&G) is nothing more than accelerate and coast which can save you gas and money and help our environment. All it takes is to accelerate to the speed you need to go and coast down 5 to 10mph (traffic permitting) and accelerate back to your target speed. Some people are getting up to 269% of their vehicles EPA rating with standard gas vehicles by shutting off the engine and coasting in neutral. I don't recommend that because you lose power steering and power brakes but why not just leave the engine running with no load during the coast. Coasting in neutral should not be done in some automatic transmissions but Ford has changed the '09 6 speed so it can be flat towed in neutral with all four wheels down. All FEH's can also be towed all four wheels down in neutral. These vehicle are now being used as toads which are pulled behind RV's because their transmissions don't require circulation of transmission fluid with a pump.

 

The P&G technique does not require slow acceleration but this does not mean you should use hard acceleration either. Most drivers use moderate acceleration which is fine because you don't want to spend a lot of time under engine load getting up to the speed limit. So those thinking all hypermilers have to drive slow are not correct. If their engine is way under powered like the '05 - '08 FEH Atkinson 2.3L, it's best not to accelerate using the electric motor assist if possible. Ethanol (E10) makes moderate acceleration worst for the earlier FEH.

 

Most automatics coast fine in "D" so there may not be any big advantage shifting to neutral. The FEH is designed to charge the HV battery while coasting in "D" using a light amount of regenerative braking. This means the Motor/generator (MG2) is using the front wheel to turn the generator to charge the HV battery. There is a big advantage shifting to "N" in the FEH for coasting because all regenerative braking is eliminated including when you apply the brake pedal. For this reason I shift back to "D" when applying the brake pedal to get that charge when slowing.

 

So, P&G can be done in every vehicle safely without shifting to "N" but works better in the FEH if you do. Also, Ford is now using fuel-cut aggressively when coasting in "D" in their newer models so the '09 FEH should remain in "D" coasting above 40mph.

 

The '09 FEH has the new Atkinson 2.5L which has much more power on E10 and I now can accelerate faster with better efficiency. Using P&G and EV mode properly, I have just increased my mileage in my '09 FWD FEH to a new record of 56mpg. I've also increased my average speed according to my SGII average tank speed.

 

Ford used Wayne Gerdes to Hypermile the Ford Fusion Hybrid with these simple safe techniques and may have started something. I was just hired to hypermile the yet to be released BMW ActiveHybrid X6 AWD with 480 horsepower. That should be interesting!

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Gary:

 

Not sure about a '09 FEH or how it's handled but a '09 FE has DFCO or decel fuel cutoff. From above something like 40MPH, coasting will activate DFCO till you touch the brakes. If one has a Scanguage -II or other scanner, you can watch for a Open Loop Status when DFCO is active. Who knows how long this has been around and used because I've seen Ford patents on DFCO for a Ford Escort in the late ninties! I think that it's been perfected much more since then because of other problems it caused.

 

As far as flat towing goes there has been a major problem with the new 6F35 used in the '09 Escape and '10 Fusion. Some RV'rs are on their third transmission. ATF is blown out the fill tube while being towed even though they follow the manual's instructions. There are TSBs about the problem which amounts to running ATF level at the low end. There is also a new dipstick with added markings. One of the affected owner's was informed by his dealer that Ford has modified the case on the 6F35s to really fix the issue.

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Gary:

 

Not sure about a '09 FEH or how it's handled but a '09 FE has DFCO or decel fuel cutoff. From above something like 40MPH, coasting will activate DFCO till you touch the brakes. If one has a Scanguage -II or other scanner, you can watch for a Open Loop Status when DFCO is active. Who knows how long this has been around and used because I've seen Ford patents on DFCO for a Ford Escort in the late ninties! I think that it's been perfected much more since then because of other problems it caused.

 

As far as flat towing goes there has been a major problem with the new 6F35 used in the '09 Escape and '10 Fusion. Some RV'rs are on their third transmission. ATF is blown out the fill tube while being towed even though they follow the manual's instructions. There are TSBs about the problem which amounts to running ATF level at the low end. There is also a new dipstick with added markings. One of the affected owner's was informed by his dealer that Ford has modified the case on the 6F35s to really fix the issue.

 

Hi Bill

 

The '05 - '08 FEH has limited DFSO but the '09 has aggressive DFSO. When you tap the brakes in your '09 FE the computer must disengage DFSO so the brakes and ABS can function properly. Tapping the brake pedal in the '09 FEH actually causes the '09 FEH to go DFSO above 40mph if the battery SoC is below 46%. Above 40mph with a SoC higher than 46% the '09 goes DFSO 3 seconds after deceleration begins. This prevents the computer from jumping in and out of DFSO so much. I believe the reason Ford programmed this 46% SoC requirement in the '09 FEH was so MG1 could maintain the 1100 RPM idle during DFSO with battery power but by tapping the brake pedal the computer is tricked into thinking MG2 is going to supply power to MG1 for DFSO. The '09 FEH will go DFSO in "L" below 40mph at any SoC. You should try "L" or downshifting in your '09 FE to see if you get DFSO above and below 40mph. If it works, you may have a way of avoiding the brake pedal to slow down and losing DFSO. Let us know!

 

This is the first I've heard that the 6F35 transmission was having problems with flat towing.

Edited by GaryG
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Hi Bill

 

The '05 - '08 FEH has limited DFSO but the '09 has aggressive DFSO. When you tap the brakes in your '09 FE the computer must disengage DFSO so the brakes and ABS can function properly. Tapping the brake pedal in the '09 FEH actually causes the '09 FEH to go DFSO above 40mph if the battery SoC is below 46%. Above 40mph with a SoC higher than 46% the '09 goes DFSO 3 seconds after deceleration begins. This prevents the computer from jumping in and out of DFSO so much. I believe the reason Ford programmed this 46% SoC requirement in the '09 FEH was so MG1 could maintain the 1100 RPM idle during DFSO with battery power but by tapping the brake pedal the computer is tricked into thinking MG2 is going to supply power to MG1 for DFSO. The '09 FEH will go DFSO in "L" below 40mph at any SoC. You should try "L" or downshifting in your '09 FE to see if you get DFSO above and below 40mph. If it works, you may have a way of avoiding the brake pedal to slow down and losing DFSO. Let us know!

 

This is the first I've heard that the 6F35 transmission was having problems with flat towing.

What could be the difference between limited and aggressive DFCO? The word "aggressive" is even used when talking about DFCO in a ICE only vehicle like one PR about the '10 Fusion! The gains are very small to begin with. DFCO operation like many other operational details isn't explained the Ford manuals.

 

The 6F35 has had other shifting issues also. I had mine in last week to have a TSB installed which was a PCM update concerning the 6F35. It shifts much better now, no harsh 1-2 shift anymore.

Edited by wptski
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What could be the difference between limited and aggressive DFCO? The word "aggressive" is even used when talking about DFCO in a ICE only vehicle like one PR about the '10 Fusion! The gains are very small to begin with. DFCO operation like many other operational details isn't explained the Ford manuals.

 

The 6F35 has had other shifting issues also. I had mine in last week to have a TSB installed which was a PCM update concerning the 6F35. It shifts much better now, no harsh 1-2 shift anymore.

 

"Limited" was my term and "Aggressive" is Ford's term when explaining DFSO (deceleration fuel shut off) in the '09 Escape and '10 Fusion. Your using what other manufactures use which is DFCO (deceleration fuel cut off). I use the term "limited" because the older FEH/MMH only have DFSO when the HV battery is to hot, cold or full and will not take a charge with regen (MG2). Instead of regen storing the energy in the battery it spins the engine RPM up to burn off this energy using MG1. Ford calls this engine braking and I've only seen it in "L" but I don't have long hills to see it in "D" here in South Florida. Fuel does get shut off during engine braking in the older FEH's but only when the battery will no longer take a charge which is rare. That's why I used the term "Limited". Ford used partial fuel shut off for years and you can see that with an Instant MPG gauge reading high MPG. Ford went to complete fuel shut off and designed the transmission and wheels to hold an engine idle so fuel return would be smooth for NVH.

 

I've read hundreds of Ford and other patents on the FEH but many were never put into production. Much of what I've learned about the FEH came from many documents and cannot be found in the Helms FEH manuals. One way I find things is to research the FEH Engineers and read their papers on the subjects. If you go back and look on the Forums I post on, sometimes I provide links and paste what the Ford Engineers are talking about new changes on new models. This was how I decided to buy the '09 FEH back in December of '07 and I started posting the information. The '09 FEH was a big improvement over prior models and I might see a 60mpg tank with up to a 900 mile distance on my daily commute this winter here in Florida. The cooler weather prevents the need for the battery to run the A/C compressor which I have no control over now.

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"Limited" was my term and "Aggressive" is Ford's term when explaining DFSO (deceleration fuel shut off) in the '09 Escape and '10 Fusion. Your using what other manufactures use which is DFCO (deceleration fuel cut off). I use the term "limited" because the older FEH/MMH only have DFSO when the HV battery is to hot, cold or full and will not take a charge with regen (MG2). Instead of regen storing the energy in the battery it spins the engine RPM up to burn off this energy using MG1. Ford calls this engine braking and I've only seen it in "L" but I don't have long hills to see it in "D" here in South Florida. Fuel does get shut off during engine braking in the older FEH's but only when the battery will no longer take a charge which is rare. That's why I used the term "Limited". Ford used partial fuel shut off for years and you can see that with an Instant MPG gauge reading high MPG. Ford went to complete fuel shut off and designed the transmission and wheels to hold an engine idle so fuel return would be smooth for NVH.

 

I've read hundreds of Ford and other patents on the FEH but many were never put into production. Much of what I've learned about the FEH came from many documents and cannot be found in the Helms FEH manuals. One way I find things is to research the FEH Engineers and read their papers on the subjects. If you go back and look on the Forums I post on, sometimes I provide links and paste what the Ford Engineers are talking about new changes on new models. This was how I decided to buy the '09 FEH back in December of '07 and I started posting the information. The '09 FEH was a big improvement over prior models and I might see a 60mpg tank with up to a 900 mile distance on my daily commute this winter here in Florida. The cooler weather prevents the need for the battery to run the A/C compressor which I have no control over now.

They or a PR on the '09 Flex stated that it was the first vehicle to use the aggressive DFCO! Not really. DFCO isn't just turning the fuel off, you have to keep the engine in a state to be able to be revived in a smooth fluid manner. Some of those patents describe some of the problems they have run into.

 

The Ford manuals are what the techs use to repair vehicles and they don't really explain in detail how most systems work.

 

I had a issue with/while coasting to a stop but not stopping but instead getting back on the throttle. "Sometimes" it would as though the engine died, no throttle response then all of a sudden it does. I thought that it was a 6F35 issue and one of the reason I got the update. It done once since the update. I'm thinking that "maybe" it's a glitch coming off DFCO.

Edited by wptski
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