OK, so I have approx 700mi on my HCH, and according the the trip computer I have averaged 43.5MPG. My daily commute is 100mi round trip and approx 50% highway.

On my way in today (prior to getting on the higway) I was averaging approx 51mpg per the trip computer, which is typical from what I have seen. When I got on the highway I put the car through it's paces. The Tach was reving up to a 5500RPM and max assist was also occuring, then I gently started easing off. When I settled in @ 65MPH, the trip computer showed me to have lost less than 1MPG overall, no biggie. I am cruising at 65MPH, and no matter what I tried, the Instantaneous FE meter was displaying 7bars or the equivalent of 35MPH. I think I could have gotten that from a gas engine '06 Civic....

The entire 25 miles or so on the higway I tried to go increase the FE. I went up in speed and then back down again, I lowered the speed to 62MPH overall, I tried using cruise. The FE on the trip computer just kept dropping....

So the factors that were apparent to me were:
1) I opened it up on the on ramp and held it there for about 30 seconds. I don't think this should have any effect, but since I have not done it before I thought I would ask.
2) Humidity was up, which again, I do not think this would have much effect until I use the A/C, which I did not engage at all.
3) The direction I travel on the highway is directly west, prior to that it is mostly N, N/W, so perhaps this was a small factor (wind?)
4) Lastly, the Batt condition was the lowest it has been, at 4 bars at the beginning of the trip, up to 5 bars before getting on the highway, and 6 bars shortly after I was on the highway, so the regen was a little more apparent than usual...

I have never seen such low FE numbers prior to this trip, so that is why I ask. My guess is a cross wind and additional charging was the culprit in the decreased FE.

I hope the more experienced here will share their thoughts....

 

What were the RPMs required to sustatin 65mph? With a CVT, the transmission should be in the optimal gear at all times, so RPMs should directly translate into how much power you are using. I believe the top gear ratio for 65mph on the 2006 model is about 2000 RPMs.

Another possiblity is that your tire pressure may have dropped over time. If your tires are underinflated, that could add a lot of drag to your system. It will be a big help to pump up your tires in the morning when the car is still cold from anywhere between the reccomended number posted on the driver side door (minimum, probably 32psi) to the pressure rating on the tire (maximum, 44-50psi depending on brand). Higher pressure means better fuel economy and handling, at the expense of noise and ride comfort. Go as high as you are comfortable with to get the best mileage.

If you were to have some underinflated tires, combined with a headwind, combined with heavy sustained charging (this can be very signifianct), that right there is a recipe for disaster, as the small engine inside the Civic is very sensitive to load changes -- and would need to wind up to a higher, inefficient RPM range to produce additional power. It may be best to try to minimize motor assist use elsewhere to cut down on this charging.

Did you enter the freeway from a dead stop on a short ramp up a very steep hill? If not, it's very unusual to need to accelerate at WOT like that. I would suggest if your battery is nearly full, go ahead and accelerate normally, but if your battery is already somewhat low, demanding maximum assist will only cost you more in the long-run as that will need to be "paid back" with charging. You can try shifting into "S" to accelerate onto the freeway, this will rev up the gasoline engine sooner and not require as much assist to get the job done. While this will cost you more gas initially, since you have a long steady drive where will not be able to replenish the electric assist with regenerative braking, it should work out slightly in your favor.

Driving at 65mph steady on the freeway for 25 miles or more should typically average in the high 40s to low 50s MPG. Also, was the 36mpg an average for both directions or only one way? It could be possible you were gaining elevation very slightly.

 

Ez2 you can follow this link and download a video I made last year:
https://www.greenhybrid.com/discuss/...7&postcount=32
Although the video is rather boring, it does show the FCD and traffic among other things for you to compare with.

Lakedude also has a video that might be helpful.

Probably the main thing that sticks out to me regarding your description is:
One can work very hard and do all the right things for many miles, and blow any achieved FE with WOT.
Cross winds also drag you down.

I was wondering why your SOC was so low.
Unless you live in a very mountainous region are you pushing it hard?
If so, that could also be a contributing factor.

 

EZ -

My experience has been that when you start any trip with 4 bars - you are almost immediately kicked into what I call forced regeneration. This continues even though you may get the SOC up to 6 or 7 bars. It does kill your mileage for that trip. The most frequent way that I end up at 4 bars is all the short distance and stop and go driving I do (uses a lot of assist to get going multiple times, but the car doesn't get up to temp to have the regen braking kick on until my trip is almost over).

Wind and hills are also definite killers. Beyond that - not sure I can add much other than to make sure you have gotten an updated mileage reading (approx every 10 second the avg MPG meter updates - so at higher speeds this is almost every .2 miles). If you opened the car up WOT - did the mileage gauge actually "register" this reading as soon as you looked at it - or did it kick in 7 seconds later? might be something to try again if you're curious. The second CAM band kicks in about 3500 rpm and I try to keep mine below that range always (emergencies excluded) in order to maximize mileage.

Eric

 

Actually, I had driven only a few short trips over the last couple of days, and I am guessing that is what caused the low reading on the SOC display.

 

The two things that drag down mileage for me so far are the following;

1. Use of airconditioning in the recirculating air mode at 70 or below.
2. Excessive trunk Weight.

 

Quote:

What factor(s) contibute most to lower FE?

1) High speed (the biggest factor)
2) Accessive acceleration
3) Late braking
4) Low tire pressure
5) Rain
6) Cold
7) Headwind
8) Airconditioning (Not outdoor temp, the hotter outside the better)
9) Using the heater
10) Stop and go driving
11) Failing to FAS (a big one)
12) Letting the engine warm up

 

I would just like to add that in the colder areas a blockheater will help when its between 40 and 50 I have the block heater on a timer to run for 1hour. within 2 blocks im up to 3 bars on the temp gauge and auto stop feature starts working sooner than before. Above 50 there is not much benefit. In my 20 mile each way commute. I showed about a 2mpg increase on that tank since installing block heater. Now that warmer weather is here I will have to wait till fall to check further with the increase in mpg. I metered what the block heater used in electricity my killawatt meter recorded 2.4kwhrs for 5days use.Thats just under .20c at .08c a kilawatt. This is the cheap version of a plugin hybrid

 

Actually, this is another potential benefit of a plug-in hybrid, the car itself could have the built-in block heater, with timers, and warm the engine as well as charge the batteries. Any extra regenerative braking power that could not be charged into the battery could be dumped into the engine-heater wires to act as a big resistor, if warm-up is needed, as well. This would save the brakes more, and heat the engine faster in cold weather. That would be quite important actually as the plug-ins woudl need to start and stop the engine much more frequently due to having more aggressive electric "assist", they'd also have more of a tendency to "cool off" in that time, and running at idle when all the power, save for hard accelerations and high-speed steady-state cruising, is coming from the electric motor would be a waste.

 

Nice thinking, with a flaw. When a plug in hybrid runs in electric mode there will always be plenty of battery capacity to absorb a charge from regenerative braking. It's highly unlikely that that there will ever be "extra regenerative braking power that could not be charged into the battery".