Re: What MPG people getting on 4WD FEH's?
 

Gary I am in Kentucky and in no way a hypermiler. I get between 34 and 35 mpg in city driving here. As you know, I got my FEH not too long after you. I started out around 32/33 mpg but then the winter hit here and I was down to 29/30 all winter long. I am now back up around 34/35. I am sure most of this due to the warmer weather but I think I am probably getting smarter about how I drive as well. I still need to try and work on my technique a lot more. I doubt I will ever get the mileage you do but it sure would be nice to get up towards 40. Either way though, I am quite happy with 34/35 and if I never exceed that I will still love this vehicle.

Re: What MPG people getting on 4WD FEH's?
 

This winter was brutal cold, single digits for a long time, teens for highs during the day....my FEH was parked in my unheated garage at night but in a deep freeze at work all day. I was mid 20's mpg all winter...I got it just as it got cold so I didn't even see 30's mpg until it warmed up :( I've never seen even mid 30's with my 09' AWD....but when I say "city" driving it's not like NYC or anything...i'm still in the country so it's a bit of stop and go if I'm in a town for errands then back to 40-60mph on the highway or backroads to get home....and alot of my nearly 6K miles so far have been highway driving for work where unless I'm missing something I don't seem to find many options to increase my mpg, some coasting here and there but I need to get where I'm going so it's cruise control most of the way.....I really do wish I could stay mid 30's around where I live though :(

Re: What MPG people getting on 4WD FEH's?
 

I looked on Cleanmpg and found one person that had a '07 FWD FEH with ~38,000 miles who averaged 36mpg and now owns an '09 FWD since 2/8/09 and averaged 34mpg in 15 - 45 degree F temps.
http://www.cleanmpg.com/index.php?page=garage&displayunits=MPG(US)&viewcar =2802

I'd say he stands a good chance to average 40mpg or better year round base on his past '07 FEH year round averages. I had a 45 LMPG average in my '05, but that was with straight gas mostly. I think on E10 I would have averaged 40 LMPG in my '05 FEH. I do increase my '05 mileage 3-5mpg when I use desertdog's technique with lots of EV driving.

You guys with the '09 FEH should know I don't accelerate much in EV and use Carl's blip to start the engine even from a stop. This builds my battery for EV cruising under 40mph. This will greatly increase your city mileage when it warms up for you.

GaryG

Re: What MPG people getting on 4WD FEH's?
 

You guys with the '09 FEH should know I don't accelerate much in EV and use Carl's blip to start the engine even from a stop. This builds my battery for EV cruising under 40mph. This will greatly increase your city mileage when it warms up for you.

GaryG[/quote]


OK, What's Carl's blip?

Mark

Re: What MPG people getting on 4WD FEH's?
 

OK, What's Carl's blip?

Mark[/quote]

Every time the engine restarts from EV mode the computer has the electric motors adjust your speed smoothly to prevent NVH during the transition to the gas mode. This is what I believe is happening because the drain on the battery is sometimes over a full 1% of the battery SoC. If your driving to get the full benefit of EV in city driving and get the best MPG possible, this drain of 1% can hold your MPG down a lot. When you start the engine by your key while in Park, the battery SoC does not drain 1% like a restart from EV. In addition, the '09 FEH will restart from EV anytime you shift to "L" and here again the battery does not drain like the automatic transfer from EV while in "D". The bottomline is to recover the battery SoC without losing this 1% each time the engine restarts from EV.

Back around September of '08 desertdog (CarlD on Cleanmpg) posted a technique he discovered that would eliminate the large drop in battery SoC after a restart from EV. He called it a reverse "Fake Shift" in his post and said he just does a quick blip to the accelerator pedal to restart the engine before it restarts on its own from EV. I think he said he used it to prevent having to sit at a stoplight while the engine was running to charge the battery. When I first tried this blip I didn't think it worked so I gave up real fast. After seeing this big loss everytime I was getting a restart I started working on Carl's blip more and got it to work sometimes. Well, it started working more and more and I've perfected it so it works almost every time now. I use it every time to restart the engine from EV now and my tank mileage has gone from ~48.5 to as high as ~53.4mpg in my '09 FEH burning E10. That's a lot of 60 - 65mpg trips when you average 52mpg tanks over 2 - 3 weeks of cold start-ups and highway driving.

You need a SGII with the SoC gauge to time everything. We all know the FEH will restart from EV at 40% SoC so you can't let the battery get that low before you blip the accelerator for a restart. This quick tap signals the engine to start, but it cuts off the message. The stardard full message for the motors to take over all the torque and allow the engine time to adjust is not relayed because there is no longer any need for torque, just the restart message. The engine can't shutdown if the SoC is to low or you quickly reapply the gas pedal for a higher RPM. This can get tricky on the '09 because if the SoC is high enough for EV, the engine will shutdown quickly. Older models don't go EV as fast or as easy.

Here is how and when I perform the accerator blip for a restart:

1. My '05 can accelerate in EV from a stop up to 30mph fairly easy because it's fully broke-in and I've gotten use to doing it. If I draw down the SoC below 40.8% I will let off the gas and shift to "N" for a coast or shift back to "D" for the blip and restart to accelerate.

2. My '09 can't accelerate from a stop near as fast as my '05, so I use the blip from almost all stops. I keep the engine running at or above 1,500rpm to accelerate to a cruising speed. The main thing I saved was that 1% loss if I had just accelerated with the gas pedal without the blip first. Remember the battery SoC operates in EV in general between 40 - 52%, so that 1% is almost 10% of the EV operating range. If I try to accelerate in EV and get a restart, I just loss 10% of my EV operating range and all the gas it takes to recover that 1% SoC. So, anytime I need to increase my speed from the EV mode, I shift to "N" and than back to "D" in decel for a blip restart and accelerate above 1,500rpm.

3. The faster your going in EV determines when you need to shift to "N" to slowdown how fast the SoC drops. For instance, if I'm going 40mph in EV I must shift to "N" at 41% Soc on my SG. The SoC will continue to drop before it gets stable but the idea is to not let it get to 40% for an automatic full message restart and 1% extra loss in SoC. For this reason I stay on the safe side and never let the SoC drop below 40.8% even at lower speeds before shifting to "N" for the glide and back to "D" for the blip restart.

4. It's all about battery SoC management and the quicker you can fill the battery for EV or highway driving the better. Don't waste SoC if you can help it. Once your battery is at 52% on the highway the engine can stop using the generator for charging and get max MPG.

I've expanded Carl's blip to prevent all those 1% losses as much as possible and I can use the savings to drive faster and on highways more when I need to. I have a ball driving my '09 FEH and getting the mileage I log:
http://www.cleanmpg.com/index.php?pa...)&viewcar=2612

GaryG

Re: What MPG people getting on 4WD FEH's?
 

Every time the engine restarts from EV mode the computer has the electric motors adjust your speed smoothly to prevent NVH during the transition to the gas mode. This is what I believe is happening because the drain on the battery is sometimes over a full 1% of the battery SoC. If your driving to get the full benefit of EV in city driving and get the best MPG possible, this drain of 1% can hold your MPG down a lot. When you start the engine by your key while in Park, the battery SoC does not drain 1% like a restart from EV. In addition, the '09 FEH will restart from EV anytime you shift to "L" and here again the battery does not drain like the automatic transfer from EV while in "D". The bottomline is to recover the battery SoC without losing this 1% each time the engine restarts from EV.

Back around September of '08 desertdog (CarlD on Cleanmpg) posted a technique he discovered that would eliminate the large drop in battery SoC after a restart from EV. He called it a reverse "Fake Shift" in his post and said he just does a quick blip to the accelerator pedal to restart the engine before it restarts on its own from EV. I think he said he used it to prevent having to sit at a stoplight while the engine was running to charge the battery. When I first tried this blip I didn't think it worked so I gave up real fast. After seeing this big loss everytime I was getting a restart I started working on Carl's blip more and got it to work sometimes. Well, it started working more and more and I've perfected it so it works almost every time now. I use it every time to restart the engine from EV now and my tank mileage has gone from ~48.5 to as high as ~53.4mpg in my '09 FEH burning E10. That's a lot of 60 - 65mpg trips when you average 52mpg tanks over 2 - 3 weeks of cold start-ups and highway driving.

You need a SGII with the SoC gauge to time everything. We all know the FEH will restart from EV at 40% SoC so you can't let the battery get that low before you blip the accelerator for a restart. This quick tap signals the engine to start, but it cuts off the message. The stardard full message for the motors to take over all the torque and allow the engine time to adjust is not relayed because there is no longer any need for torque, just the restart message. The engine can't shutdown if the SoC is to low or you quickly reapply the gas pedal for a higher RPM. This can get tricky on the '09 because if the SoC is high enough for EV, the engine will shutdown quickly. Older models don't go EV as fast or as easy.

Here is how and when I perform the accerator blip for a restart:

1. My '05 can accelerate in EV from a stop up to 30mph fairly easy because it's fully broke-in and I've gotten use to doing it. If I draw down the SoC below 40.8% I will let off the gas and shift to "N" for a coast or shift back to "D" for the blip and restart to accelerate.

2. My '09 can't accelerate from a stop near as fast as my '05, so I use the blip from almost all stops. I keep the engine running at or above 1,500rpm to accelerate to a cruising speed. The main thing I saved was that 1% loss if I had just accelerated with the gas pedal without the blip first. Remember the battery SoC operates in EV in general between 40 - 52%, so that 1% is almost 10% of the EV operating range. If I try to accelerate in EV and get a restart, I just loss 10% of my EV operating range and all the gas it takes to recover that 1% SoC. So, anytime I need to increase my speed from the EV mode, I shift to "N" and than back to "D" in decel for a blip restart and accelerate above 1,500rpm.

3. The faster your going in EV determines when you need to shift to "N" to slowdown how fast the SoC drops. For instance, if I'm going 40mph in EV I must shift to "N" at 41% Soc on my SG. The SoC will continue to drop before it gets stable but the idea is to not let it get to 40% for an automatic full message restart and 1% extra loss in SoC. For this reason I stay on the safe side and never let the SoC drop below 40.8% even at lower speeds before shifting to "N" for the glide and back to "D" for the blip restart.

4. It's all about battery SoC management and the quicker you can fill the battery for EV or highway driving the better. Don't waste SoC if you can help it. Once your battery is at 52% on the highway the engine can stop using the generator for charging and get max MPG.

I've expanded Carl's blip to prevent all those 1% losses as much as possible and I can use the savings to drive faster and on highways more when I need to. I have a ball driving my '09 FEH and getting the mileage I log:
http://www.cleanmpg.com/index.php?pa...)&viewcar=2612

GaryG[/quote]

Thanks!

Mark

Re: What MPG people getting on 4WD FEH's?
 

That would be me:D. Sure hope I can get over 40mpg after it get broken in!

Overall I am at 33.7mpg with 3,300 miles total on the '09. Worst tanks were 30.7mpg and 31.2mpg back in late Feb early March. This was a combination of low temps (10-20 degrees) and having it in for service for O2 sensor problems (see engine light thread here on GH). The car was in for service twice and they did quite a bit of test driving the second time. Good news is there has been no engine light in over 1500 miles since they replaced the exhaust manifold and second O2 sensor.

All other tanks have been all over between 33.3mpg and 36mpg. Temps are thankfully increasing, but winds have been awful as they usually are here this time of year.

Most of my daily driving is highway (two lane) and interstate. City driving is only about 20-25%. I try to do 60mph or less if traffic permits.

-- Rick

Re: What MPG people getting on 4WD FEH's?
 

Gary,

This is interesting. I've been a little disappointed with how much RPM I seem to need on the interstate to maintain 60mph. When level (which isn't very often) I need to be 1800rpm or over and can only show instant mpg in the low to mid 30s.

This may be because I am hitting the interstate at less than 52 SoC. My morning route to work starts with 10 miles of two-lane highway with rolling hills before I get to the interstate. I have been coasting down hill to take advantage of fuel cut. The SGII shows 9999iMpg and open loop going downhill when I take my foot off the accelerator. If I shift to N, it stays 9999/open loop most of the time. I'm probably maintaining or gaining speed better on the downhill, but I do notice that SoC is dropping quite a bit whenever I coast in N. So, usually I'm well below 52 SoC by the time I get to the interstate.

I know you have mentioned that shifting to N eliminates fuel cut, but that's not what I am seeing on my SGII. Problem is I am taking an SoC hit in the process. Do you know what causes the SoC to drop?

Anyway, I'm going to go back to coasting downhill in D, conserve SoC and see if that improves things on my interstate runs.

Thanks,

Rick

Re: What MPG people getting on 4WD FEH's?
 

The battery is not charged when you are in neutral (N), so of course the SoC would fall. The owner's manual is pretty clear on not using N for an extended time because of this. Battery is only charged by the ICE when in D, L or P. Not sure about reverse.

Hope that helps you. :)

-Tony

Re: What MPG people getting on 4WD FEH's?
 

Thanks for the response. I know it's not charging in N, but the thing is the drop seem to be a lot faster than it was in my 2007.

Thanks,

Rick