Not to argue but I think most of the 91 follows a river.
Rivers go downhill very gradually.

 

True... but probably not enough to be significant in this case. GPS confirmed altitude at my office (just off the 91) is 60 feet. At my home exit off the 91, it's 367 feet. At my home, it's 857 feet.

307' of rise in 20 miles shouldn't mess things up too much. That's only 0.3% grade. It's that last 490' that's the real mpg killer! That's a 5.5 grade (but parts of the climb are up to 9.6%!). Painful to watch all my hard work for the day vaporize in under five minutes!

 

Raising a ton and a half of metal 307 feet up requires the same energy whether it happens over 20 miles or over 20 feet, or zero feet (lifting the car straight up). (Of course the engine does not have the ability to lift it straight up.)

Think of how much energy it takes to push you car one foot.
Now imagine how much more energy it would take to LIFT it one foot.

Forgive me if you've already mentioned this, but have you tested freeway-only portion, each way?
I'd guess your uphill direction is worse than your downhill.

And I agree that that 490 is a MPG killer, but that 307 feet has an effect too.

 

I am in a similar situation, though I must climb up about ~800', then back down 100' on the way home (up 100', down 800' to reach the freeway onramp), much of that at about 10% grade, and with several stop signs. Repeated dash calculations have confirmed that this consistently costs me between 10-15% of my fuel economy, depending on how many shorter trips I need to make, as compard to living at the bottom of the hill. Even using every trick in the book, I was hard pressed to exceed 50mpg for more than a tank, especially considering all of the rest of my commute has hills, in some cases nearly as large (meaning I cycle my battery to <1/3 SOC then back to full multiple times a day) there's no time I ever drive on a copmletely flat section at all. Though none of the hills have as much of an impact as the one I live on.

The main difference with the steeper ones is that the regnerative capability on the Hybrid is not enough to recapture all the energy -- I still pick up speed very quikcly if I am cooasting down with full regen (brakes lightly tapped). On the very gradual hills, you can simply back off the throttle a little bit or even glide ('06), so mileage impact is not too bad. On hot days however, I "ride" the max air-conditioner with full blower on recirc all the way down, that helps brake the car, and makes the car very cold, meaning the A/C doesn't need to work hardly at all to maintain cabin temp for the whole rest of the drive.

Averaging mid 40s consistently in those conditions for a car rated for 48 mpg, while other drivers with similar commutes and driving styles are averaging 28mpg on cars rated for about 35mpg is hard to complain about. Although the Civic Hybrid regen capacity is not as much as it could be -- it's much better than zero. I also go through brakes about 4 times less often as the other people on the hill.

 

Excellent point! I never thought about it that way... and yes, I do better in the morning drive (down stream) then the afternoon.

 

Hey DT,

If you are really picking up too much speed, and want more regen (assuming you are not at maximum regen), rather than hitting the brakes, even lightly, you may want to drop the shifter to S rather than D (assuming you also are at a safe speed) to cause the revs to increase (with the valves closed and no gas being used) causing the extra energy to add maximum regeneration and slowing you down without any brakes being used.

Just a thought.

Can someone tell me what the "S" stands for? I know the D is drive and the L is low, but the S? I know it's in the manual but I have no desire to read it until this weekend


Typical Guy and Computer Geek, I know.

Best,

Michael

 

In theory, 'S' is 'Second', but it's rather silly to call it that on a CVT, so some of us have taken to calling it 'Sport' instead. Whether or not the name is suitable has yet to be decided.

 

I thought "S" was for "Sport mode". By the way, using "S" does work well for this purpose. Just remember to switch back to "D" before you get to a light, or AutoStop won't engage!!!

 

I am pretty much always at full regen either in D or S, though I will go to "S" mode if I'm picking up too much speed and don't need A/C, in order to save the brakes. However, from a fuel-efficiency standpoint, that's still kinetic energy wasted as heat (in the engine block) rather than stored as chemical energy.

 

And what does the "S" stand for???? Please???