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Hi All:

The HCH-II manual states that the tank holds 12.3 gallons, and the following:
"When the (low fuel) indicator comes on, there is about 0.9 US gal of fuel remaining in the tank before the reading reaches E. There is a small reserve of fuel remaining in the tank when the reading does reach E."
Not wanting to find out the hard way exactly how much more and needing roadside assistance, I haven't gone more than 26 miles (a bit less than 1/2 gallon for most of us) after the light (there is still 1 fuel indicator bar left). My tank filling practice is to just fill up until the pump shuts off automatically. When I do this, the fill has never exceeded 10.5 gallons per the pump, which makes me wonder if there is really almost 2 gallons of usable gas left in the tank (>100miles). I've got what could be my best tank yet (62.1mpg at 295 miles driven), and I'd like to see how many total miles I can get out of the tank.

For those of you HCH-II owners, what is the farthest distance you've traveled after the fuel light comes on? (Please include your approximate mpg and/or how many gallons of gas you think you used after the light came on).

Thanks everyone!

Mark

My 7th Gen gas-only civic has gone 50 miles after the light first went on. 12gal in a 13.2 gal tank.

Wayne, when I ran my HCH-I out of gas it took just .2 gallon over the reported tank capacity. I would not think they have any more than .25 gallon over and this is mainly for the pump itself. BTW, I only tank up on the slowest fill and stop when it clicks off the first time. When I ran out I did it the same way.

Mark--

My low-fuel light consistently comes on at approximately 10.1 +/- .1 gallons consumed. That's over the course of 30 tanks.

I believe the stated tank capacity is 12.9 gallons? I think there's more than the 0.9 gallons the US HCH-II manual states.

Last summer year I pushed a tank to 615 miles on a 10.04 gallon refill, for 61 mpg. I probably could've gotten 700-720 miles, but that would've been nerve-wracking. --RN

I've gone 30 miles or so after the gauge reads empty before, since it consistently takes less than 11 gallons to fill the tank from empty and the manual says the tank is over 12 gallons. I think they're just encouraging you not to run out of gas by turning that light on so early.

Usually the light comes on for me when there are two bars of fuel left, and I get between 35 and 50 miles from there until it is empty. I have been hovering around 45mpg's lately, which would just beat combined EPA if I bought the 2008 instead of the 2007.

I've gone about 120 miles after the last bar went away. I still probably had a decent amount of gas left since I was only able to put in 11.8 gallons until the pump first shut off.

There is probably over 2 gallons when the last bar goes away. You could just leave 0.5 to 1.0 gallons depending on how far you want to push it. It's probably just best to approximate your gallons consumed from your display fuel economy and your miles driven on the tank. The tank capacity is about 12.4 gallons if you fill to the first shutoff. Topping all the way off adds about 1.9 gallons giving 14.3 gallons.

The most fuel I have been able to put into my tank is 12.417 gal. to the top of the neck and that was several miles after the last bar went away and I felt I probably should stop. It was also before I started any techniques of hypermiling and was only obtaining 43.00556 mpg.

LL3

My low-fuel light consistently comes on at approximately 10.1 +/- .1 gallons consumed. That's over the course of 30 tanks.

I believe the stated tank capacity is 12.9 gallons? I think there's more than the 0.9 gallons the US HCH-II manual states.


My tank fills since last August have also shown the light come on just after ~10.1 gallons consumed. Based on everyone's observations, I am therefore assuming that it is from this point until the last fuel bar disappears that is the "0.9gallons until the reading reaches empty", and that the "small reserve remaining" is the ~1.3 gallons left.

Wayne- thanks for posting this thread for me while I was having "technical difficulties", and for those responding.
Mark

Just finished the tank.
Overall, got 61.2mpg (personal best so far), and went 674miles on 11 gallons. The fuel low light came on at 646 miles (was 10.5gallons based on 61.5mpg at time), and the last bar went away at 672miles. I know I could have gone further than the 2 miles I did (and could have made a 700mile tank based on your feedback), but was right next to a Costco filling station last night, and had a 36 mile commute to make to work this morning.

Thanks,
Mark

I know the pain, Mark. I filled up last week at 698 miles (with similar mileage to your newest personal best), just because my freeway commute doesn't allow convenient stopping for ~32 miles. (And of course then I would've had to pay NY gas prices!) :(

Just finished the tank.
Overall, got 61.2mpg (personal best so far), and went 674miles on 11 gallons. The fuel low light came on at 646 miles (was 10.5gallons based on 61.5mpg at time), and the last bar went away at 672miles. I know I could have gone further than the 2 miles I did (and could have made a 700mile tank based on your feedback), but was right next to a Costco filling station last night, and had a 36 mile commute to make to work this morning.

Thanks,
Mark

That is awesome!
It looks like we have the same kind of vehicle, 2007 HCH. Currently, I have driven 665.4 miles on a tank and have 3 bars left. I have ~56 miles to get home but will try to make the gas station (~45 miles) on my drive home. I will post later what the miles is when my light comes on and how much gas I put in. (or if I run out of gas).
This has been my best so far....

Ok! I am feeling pretty good now. I did not run out of gas. My fuel light came on at 684.2 miles with 2 bars. I showed 1 bar at 691.0 miles. The bars dissapeared at 706.8 miles and I made it to the gas station at 710.5 (my best yet) miles. I was able to squeeze in 12.401 gal. which brought it up to the neck.

I hope some of this data helps. I am really enjoying this site and want to help out in any way I can.

God Bless Hypermilers.

LL3

Way to go, LL3! Great info for us who wonder about such things, and continue on for awhile when all the pips go away.:eek:

Thanks,
Bob

Ok! I am feeling pretty good now. I did not run out of gas. My fuel light came on at 684.2 miles with 2 bars. I showed 1 bar at 691.0 miles. The bars dissapeared at 706.8 miles and I made it to the gas station at 710.5 (my best yet) miles. I was able to squeeze in 12.401 gal. which brought it up to the neck.

LL3

LL3- what was your final tank mpg?
Perhaps this should be a separate thread, but besides trying to keep my tank filling practices consistent for purposes of comparing tank to tank, I don't keep filling after the auto shut-off. Besides potentially causing a fuel spill, is there a downside to overfilling the tank?

Thanks!
Mark

Perhaps this should be a separate thread, but besides trying to keep my tank filling practices consistent for purposes of comparing tank to tank, I don't keep filling after the auto shut-off. Besides potentially causing a fuel spill, is there a downside to overfilling the tank?

For tank to tank comparisons, the best way is via the HCHII's display fuel economy. That will yield the most consistent results. Over many tanks, you can calibrate this with your calculated fuel economy.

From a fuel economy perspective, I really do not believe it is advantageous to top off your tank. Topping off is time consuming and it increases the risk of spilling fuel--no matter how careful you are. Also, it can foul the fuel recovery system which can lead to worse emissions. Some will argue that it decreases the amount of times you have to stop to refuel, but I believe this is minuscule. Also, it is offset by the extra weight of gasoline that you will be carrying around.

With the HCHII, you will be carrying around approximately 1.9 gallons of extra fuel. On average, you will be carrying around 10 extra pounds through the course of your driving.

I guess I could try to quantify this a bit more. For my 2nd year of ownership of the HCHII, I drove 11,607 miles and consumed 197 gallons. My average fillup was 10.36 gallons. By topping off (an average fillup of 12.26 gallons), I would have needed to fill up 16 times (instead of the 19 times that I actually did).

The question is, is the gas saved by not having to fill up those extra 3 times more than the gas consumed by carrying around an extra 10 pounds over 11,607 miles? Also, by topping off, you run the risk of fouling your fuel recovery system. I have topped off on occasion, but I still do not think it is clean or offers a fuel economy benefit.

...Also, by topping off, you run the risk of fouling your fuel recovery system. ...

John is absolutely right. While I am still not sure of any benefits I will guarantee that there are negative consequences to be had if done regularly.

In fact, there have been cases where codes were generated due to cracks and leaks in the system caused by the expanding fuel. In a warmer day, the fuel has very little headroom left to expand and the system will develop a leak under that pressure. To make matters worse, even fuel with just 10% ethanol has been found to have a "corrosive" effect on the seals of the gas cap which is in part responsible for the "Gas Cap" warning. Overfilling, spilling and splashing is not good. :(

So, the moral of the story: Perhaps we should not overfill past the first click. ;)

Cheers;

MSantos

LL3- what was your final tank mpg?

Thanks!
Mark

Mark,
My final tank mpg was 57.3, which also was the tripometer reading.


From a fuel economy perspective, I really do not believe it is advantageous to top off your tank. Topping off is time consuming and it increases the risk of spilling fuel--no matter how careful you are. Also, it can foul the fuel recovery system which can lead to worse emissions. [QUOTE]

[QUOTE=msantos;120772]John is absolutely right. While I am still not sure of any benefits I will guarantee that there are negative consequences to be had if done regularly.

In fact, there have been cases where codes were generated due to cracks and leaks in the system caused by the expanding fuel. In a warmer day, the fuel has very little headroom left to expand and the system will develop a leak under that pressure. To make matters worse, even fuel with just 10% ethanol has been found to have a "corrosive" effect on the seals of the gas cap which is in part responsible for the "Gas Cap" warning. Overfilling, spilling and splashing is not good. :(
MSantos

Mr. Kite and MS,
I had no idea about all of these negative consequences. I guess I have been fortunate by never having a fuel spill.
I have been searching for a gas station that does not have 10% ethanol but have not found one near my daily drive in Virginia or West Virginia.
Thanks for sharing this information.

LL3

Ok, a sick question - If you run out of fuel in the HCHII, what happens? I it possible to use the Assist electric motor to coast you to the nearest fuel station?

Ok, a sick question - If you run out of fuel in the HCHII, what happens? I it possible to use the Assist electric motor to coast you to the nearest fuel station?

As wonderful as that would be, the answer is, no. The EV is just for assisting the ICE. I hope this answers your question.

LL3

Actually, at the right speeds you could use an EV glide to extend what is essentially a FAS.

Actually, at the right speeds you could use an EV glide to extend what is essentially a FAS.

But if your gas tank was empty, you would not be able to get that, right? You could not just use the EV.

How would that work anyhow? If you were going the right speeds, and with light pressure feathering or pulsing the throttle, with no assist or regen, the valves are shut, right? But there is still an RPM so isn't gas still being used to turn over the ICE?

TIA,
LL3

...I it possible to use the Assist electric motor to coast you to the nearest fuel station?

Actually, we've had a couple of HCH-II owners claiming that they have done so.

Personally, I think it is not the brightest idea to let it run dry just to see if you can ride the pack for a while longer on the HCH-II... just like I think it is a fundamentally bad thing to do so on a Prius II under the same circumstances.

At first thought, I don't see why that cannot happen in principle as long as the car is not keyed off after it ran out of fuel. But if it runs out of fuel after the ICE has warmed up at least up to the point that EV glide can be evoked and sustained then it would appear to be doable.

Obviously, how far you would travel depends on your initial state of charge, but speaking from my own regular experience I can sustain a EV powered glide for the entire duration of my neighborhood at 4-5 pips of EV assist.
As usual, I do so as yet another reward for managing my SoC properly but... on a relatively flat terrain I can squeeze up to 10-15 HP of motive pack power to cover a good distance. The less aggressive the assist and the higher the initial speed, the longer the covered distance.

Cheers;

MSantos

Thanks for clarifying, Manuel -- that was the situation I was thinking of. If you are driving along at highway speeds with a high SOC and you run out, you should be able to extend the coast down substantially.

Thanks for the info MS and RLC. I learn more and more on this site each day. I just hope I never have to be the one to test that theory.:D

LL3

On my HCHII, the light usually means about 3 gallons left. Zero bars means about 2 gallons left. I get nervous after that, though, so I try to fill up quickly.

The most dangerous I've lived was to get to a point where I filled it up 11.8 gallons. Will I ever try for the big 12.0? We'll see...

I decided to push my previous limit a bit in an attempt to get a 700mile tank for the first time. It worked! The gas light came on at 650miles, second-to-last bar disappeared at 654 miles, last bar disappeared at 675miles, and my final tank distance was 713miles @ 63.1mpg.

What I don't fully understand is why when I filled-up at the gas station (my practice is to stop filling when it clicks off), the amount was 10.66 gallons, but 713 / 63.1 is 11.29 gallons. Which is the right amount of gas consumed for that tank?

Mark

Mark, you should always use the miles from the odometer divided by the gallons actually pumped.

Sean-
Odometer miles divided by gallons of gas pumped makes sense.... unfortunately, my entire log on this site (12 months worth) reflects odometer miles divided by mpg calculated by my car. If that is the case, then on my last tank, instead of 713miles / 11.29 = 63.1mpg per the car, it should be 713miles / 10.66gal pumped = 66.88mpg. Is this how you calculate and log your mileage? For this tank of mine, it is a 6% difference! Is this a normal discrepancy?

I guess it leaves me wondering how I should log my mileage now... 1.) continue to log as what my HCHII tells me it is, 2.) leave previously logged tanks as-is and log future tanks as tank miles / gallons pumped, or 3.) edit all previous tanks to log as tank miles / gallons pumped and continue to document this way from now on. I actually could do option three, as I have all gas receipts reflecting actual gallons pumped.

I appreciate your feedback,
Mark

Hi, Mark! I would go with #3 -- the pump is always the official last word in authority. ;)

Personally, I've been including the FCD readout in the notes section for my tanks so that I can track the difference between what the car tells me and what I really accomplish. Most FCDs are slightly optimistic so don't be surprised if your next fill comes in higher than you expect (indicating an underfill this time around).

Sean-
I updated my log.... on average (last 12 months), I found my iFCD to underestimate my mileage (compared with calculating using total distance/gallons gas pumped) by 3.7%. Thanks,
Mark

Hey, that's a nice improvement! It's also interesting to see that your FCD is not optimistic -- what type of terrain do you normally drive and what is the average trip length?

Hi Sean;

Unlike most (if not all) other hybrids, the HCH-II almost always underestimates the FE 99.0% of the time.

Cheers;

MSantos

Really? I wasn't aware of that! My Insight seems to wander around an average that is pretty much right on...

Yes, it is true.

In fact, I found it almost unbelievable when my 2006 actually over-estimated the FE for the very first time after some highway driving during this summer.

I guess it depends mostly on the driver and driving regimen but for the average HCH-II this under-estimation is quite normal and a good piece of HCH-II trivia. ;)

Cheers;

MSantos

I drive with rush-hour traffic 37miles each way to work. First 4 miles are 40mph rds to the expressway, then ~30 miles expressway (I usually drive 55-60mph), then ~3 miles 40mph surface streets again. On the way to work, there is a slight downward slope overall, and upward on the way home.

I admit that I am pleased to have learned that my iFCD underestimates my overall FE. I felt like I was really using all techniques I had seen and learned on this site, but not achieving the results that many others have been. I got an engine block heater right around New Years, which helped significantly in the colder weather. Another driving change that I made only this spring that significantly bumped up my FE was to NOT use cruise control (which in retrospect I had lazily been using from Sept 07), in favor of DWL and monitoring the iFCD like a hawk, backing off to hold my mpg in the 80-100mpg range as much as possible. At first, my foot/lower leg got pretty tired of this, but have gotten used to this, and can't see myself getting lazy again, given the FE increase I experienced! I am always scouring this site to try and find any HCHII FE tricks that I haven't yet come-across, but admit it's getting harder. Notably, I have not purchased a scangauge. I have been thinking about it, for my wife, who dries an 08 Odyssey. I'm not sure how much additional FE benefit I would get from it. What do you think?

Mark

Hi Mark,
I came to the same conclusion, and our mpg on the same year/make of car looks about the same. I am working on raising it into the 60's...a lot of hard and sometimes frustrating work. The only thing I do not like is using the EPA average that was assigned for our cars in 2007. Even they admitted later that these numbers were off. I think they are somewhere between 42/45 instead of 49/51. Any way you look at it though, we are kicking butt!

LL3

LL3-
I agree we are doing well! When I read wayne's thread where he got to test-drive a HCHII (http://www.cleanmpg.com/forums/showthread.php?t=13754&page=4 ) and got 70+mpg over 500 miles, I can't help but to think there are more tricks of the trade for us to improve on! :D

Mark

This is absolutely correct. Our HCH-II underestimates while our Prius usually overestimates.

Regarding more tricks for high MPG, I suggest looking at some of Msantos discussions. In the summer months,
70's and 80's are very possible.

Cheers!!

Hi Sean;

Unlike most (if not all) other hybrids, the HCH-II almost always underestimates the FE 99.0% of the time.

Cheers;

MSantos

I have run the '08 HCH to no lights twice and on one of those occasions ran 20 miles before the fill up. I have never taken more than slightly over 11 gallons. I wonder why there are reporting discrepancies between individual cars of the same type.

The car says that the overall MPG since first birthday is 51 mpg. But on the reported miles and gallons here I'm over 53. I do not mind the under-reporting but at first I got anxious when I had a "bad" tank.

How would that work anyhow? If you were going the right speeds, and with light pressure feathering or pulsing the throttle, with no assist or regen, the valves are shut, right? But there is still an RPM so isn't gas still being used to turn over the ICE?

TIA,
LL3

No. When you go down a hill, and ease up on the gas pedal, you will see the instantaneous fuel consumption gauge (I always leave that display up, if the engine were to overheat, I'm sure that the computer would let me know) start to climb. At some point, there is a tiny "bump" and the bars zoom up to 100 MPG. That bump is the engine turning off all fuel, and switching the intake valve timing to minimize pneumatic losses. At that point, it is using ZERO gasoline, until you press harder on the pedal. The engine is still spinning, it has to, because, unlike the Prius, the traction motor/generator is built into the engine flywheel. But, it can run with no fuel consumption when going down hills, coasting to a light, etc. When going down gradual hills, you may need to press very lightly on the gas to keep the normal regenerative braking from slowing you down. You can even apply electric power only, with VERY light pedal pressure, to make it over the top of a hill, and do a series of hills with a general downward trend, without starting the engine at all.

Jon

yes the instrument panel will beep (like when you drive with the park brake on) and the display will change to the thermometer