Honda Civic Hybrid hill strategy
#1
09-20-2005, 07:53 PM
Hill strategy Honda Civic Hybrid
I'm trying to optimize my gas mileage in my 2005 Honda Civic Hybrid with CVT transmission. Going up the hills on country roads in Connecticut is the greatest drain.
I'm trying to determine the optimal speed for long hills that I can't simply coast up with accumulated momentum. On flats and slight inclines there seems to be a "sweet spot" in the CVT gear range at about 42 to 45 mph when the tachometer reads about 1,800 rpm. I can sometimes sustain gas consumption as good as 80 mpg. (If the tachometer is reading higher, I take my foot off the accelerator until the gears shift into a higher gear range and the tachometer drops. With a very light touch on the gas I keep the tachometer around 1,800 and avoid a downshift of the gears and an increase in the rpm. There seems to be a relatively high torque available at this point for the fuel used.)
Long hills seem to be best also around 42 mph although obviously the gas consumption gets much worse as the engine labors even with the IMA boost (which eventually discharges to the 50% on the battery and then the engine even starts recharging the battery a little)..
QUESTION 1: What is the best advice regarding specifics of the IMA boost percentage and speed to seek on long uphills in the country where the speed limit is in the 35 to 50 mph range? (this is already the least hilly route)
QUESTION 2: What about the best strategy for climbing long hills on an Interstate highway where the speed limits are in the 55 mph to 70 mph range?
Many thanks
I'm trying to determine the optimal speed for long hills that I can't simply coast up with accumulated momentum. On flats and slight inclines there seems to be a "sweet spot" in the CVT gear range at about 42 to 45 mph when the tachometer reads about 1,800 rpm. I can sometimes sustain gas consumption as good as 80 mpg. (If the tachometer is reading higher, I take my foot off the accelerator until the gears shift into a higher gear range and the tachometer drops. With a very light touch on the gas I keep the tachometer around 1,800 and avoid a downshift of the gears and an increase in the rpm. There seems to be a relatively high torque available at this point for the fuel used.)
Long hills seem to be best also around 42 mph although obviously the gas consumption gets much worse as the engine labors even with the IMA boost (which eventually discharges to the 50% on the battery and then the engine even starts recharging the battery a little)..
QUESTION 1: What is the best advice regarding specifics of the IMA boost percentage and speed to seek on long uphills in the country where the speed limit is in the 35 to 50 mph range? (this is already the least hilly route)
QUESTION 2: What about the best strategy for climbing long hills on an Interstate highway where the speed limits are in the 55 mph to 70 mph range?
Many thanks
Last edited by drquine; 09-20-2005 at 08:03 PM.
#2
09-20-2005, 08:34 PM
Re: Honda Civic Hybrid hill strategy
when I was playing around in the hills of wisconsin I found the only way to deal with prolonged hills was to just lower my speed and and think light thoughts 
It was tough and I could only eek out about 60mpg Sometimes my speed fell to about 45 so I would accelerate up to 55 or 60 and just allow it to slowly decelleratate. Rinse and repeat as needed.
It was tough and I could only eek out about 60mpg Sometimes my speed fell to about 45 so I would accelerate up to 55 or 60 and just allow it to slowly decelleratate. Rinse and repeat as needed.
#3
09-21-2005, 09:43 AM
Re: Honda Civic Hybrid hill strategy
I've driven rt 84 thru ct lots. (grandma lives on the cape) I know what you mean about the long hills dragging down your average. I found my best bet was to really try and keep my momentum up by getting a good running start (driving with load) of at least 65mph. Then at the bottom of the uphill I'd go right to 40mpg & try to kick in assist to hold 40mpg for the hill. this way I could usually maintain >50mph- especially if I could get in behind a truck to wind break in front of me (not true drafting- about 5 car lenghts back)
if I hit the bottom of the hill at 55-60mph, I was usually at <50mph by the top and worrying about getting run over. This usually nets me 52-56mpg for trips from ny to the cape over 280 miles- though on the cape I can get high 50's to 60mpg so that usually pulls my average up.
locally/suburban- again, momentum is your friend. I try to be going 35-40mph at the bottom of the hill and again maintain 40mpg with boost going up.
I did do some experiments over a local mountain where I couldn't get a running start (stop & turn at bottom, with windey road). there the best results seemed again to be trying to keep the fcg as high as possible- but I usually ended up going 20mph at the top of the hill, which was unacceptable if another car was behind me. plus then the car downshifts and uses more gas anyway.
I think you really need to experiment with your own individual hills and approaches to work out what is the most fuel efficient and safe.
hope this helps. where in ct are you? east or west? I'm near the TZ bridge.
Kate
if I hit the bottom of the hill at 55-60mph, I was usually at <50mph by the top and worrying about getting run over. This usually nets me 52-56mpg for trips from ny to the cape over 280 miles- though on the cape I can get high 50's to 60mpg so that usually pulls my average up.
locally/suburban- again, momentum is your friend. I try to be going 35-40mph at the bottom of the hill and again maintain 40mpg with boost going up.
I did do some experiments over a local mountain where I couldn't get a running start (stop & turn at bottom, with windey road). there the best results seemed again to be trying to keep the fcg as high as possible- but I usually ended up going 20mph at the top of the hill, which was unacceptable if another car was behind me. plus then the car downshifts and uses more gas anyway.
I think you really need to experiment with your own individual hills and approaches to work out what is the most fuel efficient and safe.
hope this helps. where in ct are you? east or west? I'm near the TZ bridge.
Kate
#4
09-21-2005, 09:46 AM
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Re: Honda Civic Hybrid hill strategy
https://www.greenhybrid.com/learn/ar...fficiency.html
(With minor modifications)
(With minor modifications)
Climbing a Hill
Bigger hills are the second main MPG killer. If this is a familiar route, perhaps you can find a different road going around the hill. Pick a route that doesn’t add significant distance to your trip. Raise the FCD whenever it is possible and try for just 2 or 4 MPG even if only temporarily in mid-hill. Most hills have flatter areas as you climb. Learn to watch for these flatter areas and take advantage of them whenever possible.
Use the IMA on hills very sparingly. If Assist comes on you are pulling hard and need to try and squeeze just two or four more bars out of the FCD meter. Sometimes you just can’t avoid it but back off as soon as you can.
The CVT can do some fairly unpredictable things climbing a big hill. If the FCD is down to one segment below 40 I can usually lock some Assist in at that point. Sometimes I can back off to 40 MPG and still have the Assist locked in, keeping my speed schedule up the hill. Feather back as the hill begins to flatten out near the top.
If it is a common daily route then experiment with climbing those familiar hills using no Assist at all. Often times it can be done and if you stay off of the Assist you'll see some real fuel savings. You don't know if you don't try.
Don't continually change the throttle position in mid-hill by very much- keep it fixed into position.
Drive with the load. Don’t maintain speed climbing hills. Try to guess the time it will take to reach the crest. Also decide the minimum speed required at the crest.
As you climb the hill, slow down gradually and attempt to time it so the minimum speed is reached near the top. Hills are not linear from bottom to top so some minor FCD adjustments are made.
In heavier traffic, often times 18 wheel trucks will drive with the load and will be going slower in the right lane up a big hill. If you follow at a safe distance then it appears that the truck is going slow, not you. Same goes with any slower vehicle in the right lane.
If you reach the top of a tall hill and find a short flat area that leads to another big hill you are at a disadvantage because of your minimum speed. Accelerate as easy as you can on the flat area and time the next crest as you did for the first hill.
Rolling Down a Hill
Always plan ahead. If I know the decline is immediately followed by a steep uphill I will usually begin my decent with as much MPG as I can or in FAS or N, then before I reach the bottom I'll add enough accelerator and gain momentum for the onslaught of the incoming hill. If the hill flows down to a long, flat road at the bottom I'll hold my built momentum.
Bigger hills are the second main MPG killer. If this is a familiar route, perhaps you can find a different road going around the hill. Pick a route that doesn’t add significant distance to your trip. Raise the FCD whenever it is possible and try for just 2 or 4 MPG even if only temporarily in mid-hill. Most hills have flatter areas as you climb. Learn to watch for these flatter areas and take advantage of them whenever possible.
Use the IMA on hills very sparingly. If Assist comes on you are pulling hard and need to try and squeeze just two or four more bars out of the FCD meter. Sometimes you just can’t avoid it but back off as soon as you can.
The CVT can do some fairly unpredictable things climbing a big hill. If the FCD is down to one segment below 40 I can usually lock some Assist in at that point. Sometimes I can back off to 40 MPG and still have the Assist locked in, keeping my speed schedule up the hill. Feather back as the hill begins to flatten out near the top.
If it is a common daily route then experiment with climbing those familiar hills using no Assist at all. Often times it can be done and if you stay off of the Assist you'll see some real fuel savings. You don't know if you don't try.
Don't continually change the throttle position in mid-hill by very much- keep it fixed into position.
Drive with the load. Don’t maintain speed climbing hills. Try to guess the time it will take to reach the crest. Also decide the minimum speed required at the crest.
As you climb the hill, slow down gradually and attempt to time it so the minimum speed is reached near the top. Hills are not linear from bottom to top so some minor FCD adjustments are made.
In heavier traffic, often times 18 wheel trucks will drive with the load and will be going slower in the right lane up a big hill. If you follow at a safe distance then it appears that the truck is going slow, not you. Same goes with any slower vehicle in the right lane.
If you reach the top of a tall hill and find a short flat area that leads to another big hill you are at a disadvantage because of your minimum speed. Accelerate as easy as you can on the flat area and time the next crest as you did for the first hill.
Rolling Down a Hill
Always plan ahead. If I know the decline is immediately followed by a steep uphill I will usually begin my decent with as much MPG as I can or in FAS or N, then before I reach the bottom I'll add enough accelerator and gain momentum for the onslaught of the incoming hill. If the hill flows down to a long, flat road at the bottom I'll hold my built momentum.
Last edited by Hot_Georgia_2004; 09-21-2005 at 09:51 AM.
#5
09-21-2005, 05:32 PM
Re: Honda Civic Hybrid hill strategy
Tom - Climbing a long hill you think it is best to coast down to 45 then accelerate to 65 and cycle through that process? My impression is that speeding up takes more energy than a steady speed. My hunch is that we need to identify the "best" speed and then grin and bear the gas consumption at that speed until the hill lets up. - Doug
Last edited by drquine; 09-21-2005 at 05:35 PM.
#6
09-21-2005, 05:43 PM
Re: Honda Civic Hybrid hill strategy
Kate & Hot_Georgia - These techniques are what have enabled me to move from 38 mpg (first tank) to 55 mpg (current tank). Getting good speed going downhill and then having good momentum on the next hill up is very effective. I'm getting good at estimating the momentum and gas necessary to be moving at the lowest acceptable speed at the next crest. However, even on the least hilly road there is at least one long steady hill going both ways to work for which momentum is killed early and some speed has to be selected and paid for in gas. As I noted in my question, it seems to me that about 42 mph is the speed at which regardless of the slope I get the best mpg. Tomorrow I will experiment with trying to minimize the IMA (I'd thought that taking it to about 50% got the best mpg) and see how I do. Currently I have it worked out that the long hill gets me drained down on the battery to the 50% mark where the engine starts trying to recharge. (I commute from near Danbury to Shelton). Subsequent hills get me fully charged so every day both ways I go from full to 50% chatge and back.
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