Occasional Fuel Economy Problem with my HCHII
#11
Re: Occasional Fuel Economy Problem with my HCHII
No, what I am saying is that I have had the same thing happen, but it did not last the entire trip as you are describing. In my situation it was due to some level of forced regen. I have been reading this forum and others seem to suggest that there may even be a level of forced regen, that they can feel, but is below the 1 green bar display threshold, so you can not really verify it with the display. Normally in my situation there is 1 bar being displayed and simply letting off the gas more does not bring the mpg meter up above 50mpg. I have had this happen at almost a full SOC, so I think that the computer is not simply monitoring the SOC level (ie voltage), but is actually flow rate into and out of the battery (amperage). I think this is a fairly reasonable theory since both the regen and assist meters must be measuring amperage and not voltage, so obviously the computer would have this data at it's disposal for optimization. I have experienced this issue more when I was driving in a steady state situation with little regen opportunities. My theory is that the computer may be stealing some regen during these situations as it sees a slow negative charge rate situation starting. This is probably more efficient and easier on the battery pack than waiting for the SOC to drop down to 4-5 bars and pulling a large forced regen cycle. That would require more amperage and generate more heat in the battery, not to mention be more noticeable to the customer.
I was also pointing out to you that I have also noticed at times that I was not at the optimal mpg situation due to the CVT gear ratio and rpm settings I was at. Letting slowly off the gas as you described was not enought to get the CVT transmission to switch the ratio. I had to let up fully off the gas, go to full regen and then reapply the gas slowly to get the rpm's down and the mpg back up. Sorry if my attempts to help you insulted you in any way, but I have only had the car for 3 weeks and I am learning a lot every time I drive it.
I was also pointing out to you that I have also noticed at times that I was not at the optimal mpg situation due to the CVT gear ratio and rpm settings I was at. Letting slowly off the gas as you described was not enought to get the CVT transmission to switch the ratio. I had to let up fully off the gas, go to full regen and then reapply the gas slowly to get the rpm's down and the mpg back up. Sorry if my attempts to help you insulted you in any way, but I have only had the car for 3 weeks and I am learning a lot every time I drive it.
Last edited by cherokee180c; 08-23-2006 at 10:01 AM.
#12
Re: Occasional Fuel Economy Problem with my HCHII
I wasn't insulted. I'm just a little bit frustrated at this problem. I can just imagine trying to explain it to a service technician. I'm sure they will look at me like . If it keeps happening, I will just try to pay more attention to all the variables and see if I can figure it out.
Thanks.
Thanks.
#13
Re: Occasional Fuel Economy Problem with my HCHII
My experience is that my drives can be categorized into three levels...
1) "Super" days, where I look at the instant meter and it's always +55 (even climbing mild grades!)
2) "Average" days; usually with the "mild regen" and one green bar
3) And the (thankfully) rare "Stinky" days. Usually associated with 100+ temps, no A/S, etc.
I'd say 25% of my drives fall into the "super" category, 70% fall into the average and 5% are "stinky".
When I do have the average drive... with the one annoying green bar, it seems even if I lightly accelerate (up a slight grade), the bar won't go away. For this reason, I feel it's a form of forced regen. Why else would it indicate a charge, when I'm not decelerating?
Where my situation differs from Mr. Kite's is that I CAN get over 50 mpg without completely backing off the throttle (mostly depending upon the grade). If I'm on level to slight downgrade, I can get 50mpg or better, even with the mild forced regen. Of course, the more downgrade you have, the more regen... and the harder it is to determine if it's "forced" or not! I can usually tell, though, since I'm driving the same route every day. One day I'll be getting two regen bars and 50 mpg... the next ("super") day I'll be getting one regen bar and 60 mpg on the same stretch.
Of course, some of this could be other outside factors (winds, temps, speed, etc.), but these are usually quite consistent for me from day to day.
1) "Super" days, where I look at the instant meter and it's always +55 (even climbing mild grades!)
2) "Average" days; usually with the "mild regen" and one green bar
3) And the (thankfully) rare "Stinky" days. Usually associated with 100+ temps, no A/S, etc.
I'd say 25% of my drives fall into the "super" category, 70% fall into the average and 5% are "stinky".
When I do have the average drive... with the one annoying green bar, it seems even if I lightly accelerate (up a slight grade), the bar won't go away. For this reason, I feel it's a form of forced regen. Why else would it indicate a charge, when I'm not decelerating?
Where my situation differs from Mr. Kite's is that I CAN get over 50 mpg without completely backing off the throttle (mostly depending upon the grade). If I'm on level to slight downgrade, I can get 50mpg or better, even with the mild forced regen. Of course, the more downgrade you have, the more regen... and the harder it is to determine if it's "forced" or not! I can usually tell, though, since I'm driving the same route every day. One day I'll be getting two regen bars and 50 mpg... the next ("super") day I'll be getting one regen bar and 60 mpg on the same stretch.
Of course, some of this could be other outside factors (winds, temps, speed, etc.), but these are usually quite consistent for me from day to day.
#14
Re: Occasional Fuel Economy Problem with my HCHII
My experience is almost exactly like yours Anahymbrid with the only exception being that I can usually only get 50 mpg when in a forced regen, not over unless going downhill. Some of this may be the fact that the car is only a month old with under 1500 miles and not fully broken in.
#15
Re: Occasional Fuel Economy Problem with my HCHII
Here's a new twist to this issue... this morning I had only four bars on my SOC. That's fairly low. The surprising thing was that I was in "super" mode! No forced regen at all... no green bars at normal cruising. By the time I got to my office, I was back to seven bars. I guess it was all from normal regen by coasting on the few downgrades.
I sure wish I knew the conditions the computer uses to put the car into forced regen mode. It's like a surprise each day!
I sure wish I knew the conditions the computer uses to put the car into forced regen mode. It's like a surprise each day!
#16
Re: Occasional Fuel Economy Problem with my HCHII
Been running into the same confusion, Jeff. It's just not too predictable when the car is going to throw you into auto-charge. I recently posted in cleanmpg about my frustration in the forced charging at high SoC leading to 'forced friction braking'. Post here:
http://www.cleanmpg.com/forums/showt...3743#post13743
But the other suspicions about 'stealth' forced charging are also troubling. Sub-1-green-bar charging that may be on quite often. ANybody else can confirm this?
http://www.cleanmpg.com/forums/showt...3743#post13743
But the other suspicions about 'stealth' forced charging are also troubling. Sub-1-green-bar charging that may be on quite often. ANybody else can confirm this?
#17
Re: Occasional Fuel Economy Problem with my HCHII
Originally Posted by dogarm
Been running into the same confusion, Jeff. It's just not too predictable when the car is going to throw you into auto-charge. I recently posted in cleanmpg about my frustration in the forced charging at high SoC leading to 'forced friction braking'. Post here:
http://www.cleanmpg.com/forums/showt...3743#post13743
But the other suspicions about 'stealth' forced charging are also troubling. Sub-1-green-bar charging that may be on quite often. ANybody else can confirm this?
http://www.cleanmpg.com/forums/showt...3743#post13743
But the other suspicions about 'stealth' forced charging are also troubling. Sub-1-green-bar charging that may be on quite often. ANybody else can confirm this?
Some of us are actually working on HCH-II add-ons that help manage the SoC for this and other reasons. So far the results are pretty good and I expect to have my vehicle modded with the ehnancement soon.
Cheers;
MSantos
#18
Re: Occasional Fuel Economy Problem with my HCHII
Thanks for the confirmation. Regarding the non-resetability, I saw someone who suggested FAS, thinking it would stop the problem, but I've tried twice and it didn't prevent further regen, even at 6-7 bars.. The 6-bar forced regen is annoying the crap outta me. My Civic rarely even goes down to 5 bars, much less 4. It's like the BCM is keeping it in the narrow upper range. MAybe for better battery life, sure, but I don't think it is sensible for FE.
I'm also wondering if the SoC meter is simply inaccurate, much as I have seen often with cell phone meters. So maybe my 6&7th bars are actually a bigger-than-1/8th-charge-sized units, if you know what I mean. So maybe I am draining down lower than I think based on the gauge, but the onboard computer knows better. Just a thought.
Keith
I'm also wondering if the SoC meter is simply inaccurate, much as I have seen often with cell phone meters. So maybe my 6&7th bars are actually a bigger-than-1/8th-charge-sized units, if you know what I mean. So maybe I am draining down lower than I think based on the gauge, but the onboard computer knows better. Just a thought.
Keith
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