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Hybrid Vehicles Honda Civic Hybrid Honda Civic Hybrid MPG-Real World Numbers
475 messages, Last post on Dec 04, 2009 at 3:11 PM
You are in the Honda Civic Hybrid Forum. Your Host is pf_flyer
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I've owned one since new. Mileage peaks soon after purchase, within 5-10 thousand miles as rings seat and compression peaks. The key to reductions in mileage as time passes is the condition of the battery. When the battery begins to fade it begins to lose charge internally - the amount of energy it contributes to propelling the car forward is reduced. When the computer asks for energy the battery responds with reduced voltage under load. The computer reads this lower voltage as meaning the battery has less to contribute (it actually does) and so it asks for less. Meanwhile, the lower voltage causes the computer to spend more time recharging the battery (to bring up its low indicated voltage). This energy comes from fuel burned unless you are coasting downhill. The energy is lost due to reductions in the chemical efficiency, and increased internal resistance in the battery. I've noticed a change in the ratio between the amount of time the battery is charging versus the amount of time the battery is discharging and providing propulsion. Charging (green) goes up. Interesting, their choice of color here. The color that saves fuel is white, the color which uses fuel is green, and interesting juxtaposition. Honda does not wish to be replacing everyone's batteries under warranty, so they program the computer to be very accepting of this lower voltage condition. After all, as other writers have noted, Honda is not promising any certain mileage figure. At some point the battery will fail completely, but before that, the mileage will drop significantly as the battery absorbs charging energy, but gives back little in propulsive force.
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Replying to: gm_nut (Jul 06, 2009 9:11 am) |
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Here's a real puzzler. I have a 2008 Honda Hybrid Civic that I got this past January, bought new, and that just turned 6,000 miles. I replaced a 2008 that was totaled. When I first got it I averaged 47 mpg consistently, (same as the first one, 50 on the highway), because I check the mileage every fillup. All of a sudden my mileage has dropped to around 40-42 and it seems to be getting less and less. Since I live in Florida, the car's air conditioner runs consistently since April. Can use of the air conditioner reduce mileage this much. I talked to the agency and they couldn't explain it. It's maddening! jtisch |
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Replying to: jtisch (Jul 23, 2009 6:13 pm) That is the problem with hybrids, they have to try to make them civilized to drive, to behave like a non hybrid. It takes a lot of technology and compromises to achieve that goal. I live in Idaho, and have the opposite problem, the colder it gets, the worse the mileage, due to the basic fact that a cold engine needs more fuel. The best mileage i get is when its about 85 out and I run with the a/c off and windows open.
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Replying to: mrwaug (Jul 23, 2009 9:11 pm) jt
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Replying to: jtisch (Jul 24, 2009 5:31 pm) I am not sure about Honda, but other manufactures will have a different set of operating perameters during break in, in which you can expect to see lower mpg and horsepower. once you hit 10 to 20k miles, then things start working as they should. But this does not explane why you had high mpg and they are lower now. Try resetting your mpg counter and take it for a drive with the A/C off during the evening or night, this might show you what your numbers might be like without A/C |
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Replying to: KarenS (Jun 20, 2005 11:34 am) Didn't reset any trip meters during the entire 1,800 miles. I noticed on older messages on Forums 2004, 2005 that people were reporting decent mpg. Is something wrong with my new 2009 Civic Hybrid? I also noted on one message long ago, that a long break-in period does very little to boost gas mileage. We do normal combination city/highway driving, no drag racing!!
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Replying to: frednjudik (Jul 25, 2009 11:53 am) Obviously there are the old stand-bys like how you drive and tire pressure. But especially during the summer, many states mandate different approaches to oxygenate fuel for smog reduction. One way is to blend in ethanol. If you are gassing up at a pump that says something along the lines of "contains up to 10% ethanol" then that will be another factor in reducing your gas mileage because ethanol doesn't have the same energy content as gasoline. It's lower. Also, where you fill up matters big time. It's the same issue as what grade of gas you buy. By law, gasoline can have a range of octane values that still qualify it as "regular" or "premium". It's more profitable for vendors and refiners to push those to the low end. If the gasoline you use does not burn as efficiently in your engine, at your altitude, etc, then you will get lower mileage. (And if anyone quips in that it doesn't matter because modern cars have knock sensors, they are incorrect. Even with knock sensors, if you are running a real octane value too low or too high for what your engine runs most efficiently with, your engine will get lower mileage. Retard the timing and the engine is less efficient and you have to put more fuel and air in to get the same power out. Richen the mixture and you are directly lowering the mileage. All knock sensors allow modern engines to do is to keep running without damaging the engine because of pre-ignition, aka detonation and knock.) My personal experience - backed up with the dash gauges, manually verifying the mileage with gallons filled up and mileage driven, and switching between different brands and grades of gas - is that in my area "mid-grade" gasoline from Chevron gets me the best mileage and the difference is enough to more than cover the difference inn price over buying the lowest cost regular, or even just regular at Chevron or other gas stations. It is a very false economy to always hunt the lowest gas prices. What people generally end up with is an inferior grade of gas that actually costs them more in the long run because their mileage is reduced. Also, the brand of tires can make a huge difference as well as the previously-mentioned tire pressure. Some tire rubber compounds are "stickier" and/or the construction of the tire just causes more rolling resistance in a trade off for better handling or whatever. I changed tires on my car and watched my mileage take a consistent 5 mpg hit. It rides nicer and feels like I have more control and maneuverability, but I haven't seen my previously common 50 mpg since. Even with pumping these tires up to the max recommended pressure, my mileage now is right at 45 mpg. The change was like night and day and happened right when I got the new tires. It was frustrating enough that I almost took them right back off and put on new Bridgestones which were what the car came with new. What I put on were Michelins.
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Replying to: refields (Jul 25, 2009 12:21 pm) It may be related to heat, as our temperatures have been in the low 100's for a week and a half, however we drove over to the coast last week for three days where it was in the mid 70's. Thanks for any info. anyone can provide.
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Replying to: frednjudik (Jul 25, 2009 4:58 pm) If you are fueling up at CostCo, on what basis do you exclude fuel quality? Have you tried other brands and grades to do any comparative testing? CostCo is going to be a bargain fuel reseller. I would put CostCo in the same category as buying gas at a convenience store. Maybe their gasoline is the primo stuff, fresh from the refinery and the octane rating spot on what is claimed, but I wouldn't bet on it. And if the temperature has been in the 100's, are you running the air conditioner? Any engine load will reduce mileage. Just for kicks, why not try a mid-grade tank from one of the majors? It will cost you 10-20 cents more per gallon - all of one to three dollars extra - but you might be pleasantly surprised. Then, if you do get better mileage, calculate out the cost per mile of gasoline costs and see which is lower. And if you do get 5 mpg extra, with a 12 gallon tank, that's an extra 60 miles - or a free gallon (1.2 gallons at 50 mpg) of gas and then some. If the difference in cost of a tank of regular and a tank of mid-grade is less than the cost of 1.2 gallons of regular, it's cheaper to run mid-grade.
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