How to calculate MPG
#41
06-04-2006, 08:01 AM
Re: How to calculate MPG
Originally Posted by CGameProgrammer
EPA also "shows" the Accord Hybrid losing 4 mpg by getting a sunroof, but that's not true at all -- it's just a sign of the inaccuracy of EPA testing.
A heavier vehicle gets worse mileage.
The EPA test results is used for comparison purspose and is accurate.
The city mileage is better than highway's among the HSD(THS) vehicles on EPA tests. I never seen any reverse result of accuracy on the EPA test results.
I have driven Priuses, Civic Hybrids (2005 & 2006), the Accord Hybrid, and the Camry Hybrid. Believe me, HSD gets better highway mileage than IMA with all else being [more or less] equal. Perhaps you should drive the vehicles you talk about, but I bet you haven't driven the Hondas.
I have driven Honda hybrids, so what?
I never said HSD is worse than IMA. They are almost same.
City driving is not "any speed below 42 mph". I have achieved well over 40 mpg many times, but only on the rare occasion that I can take a long commute where there's very little traffic. When there is traffic, 35-37 mpg is the absolute best I can do, and I do better on the highway. That's because traffic often stops unexpectedly, so I can't always coast, and I'm certainly not the kind of person to make traffic much worse by holding it up to accelerate in EV mode. That kind of practice pisses everyone off, including me. The Prius accelerates fairly acceptably with electric power alone, but the Camry usually does not (the threshold when the engine comes on seems to vary).
Of course, driving in Japan may be different?
Of course, driving in Japan may be different?
It is your decision how to drive your car. You drive your car using your gasoline.
Ken@Japan
Last edited by ken1784; 06-04-2006 at 08:04 AM.
#42
06-04-2006, 08:16 AM
Re: How to calculate MPG
That is what I would expect as well. If that is a correct assumption why would it matter if its topped off or not? That shouldn't have any affect on the calculation. Hence, the questions 
.
.
Originally Posted by spiff72
I have a fuel economy/trip computer in my 02 Trailblazer, and I am fairly certain that there is a sensor that is monitoring the amout of fuel being used (instantaneously). I don't think that it is based on the fuel gage - I think this would be far too inaccurate.
It then keeps track of the cumulative instantaneous values, and uses those to calculate the average MPG.
It then keeps track of the cumulative instantaneous values, and uses those to calculate the average MPG.
#43
06-04-2006, 08:23 AM
Re: How to calculate MPG
I think that the effect it has on calculations is that your "hand calculated" figures can be inaccurate (vary from the TCH's figures) the because the amount of fuel used will vary from tank to tank because of the pump shut-off variations.
Topping off will give more consistent values from tank to tank, since the gas pump isn't what decides when to stop -- YOU do!
Topping off will give more consistent values from tank to tank, since the gas pump isn't what decides when to stop -- YOU do!
#44
06-04-2006, 08:28 AM
Re: How to calculate MPG
On another note, I think I would trust the internally calculated numbers, since it isn't really calculating per tank - it is calculating based on fuel used. The amount of fuel replaced during each fill-up really becomes meaningless, since the internal calculations don't "care" whether you filled up the entire tank filler neck when you filled it up.
#45
06-04-2006, 03:10 PM
Re: How to calculate MPG
Originally Posted by ken1784
I don't understand your point.
Again,I would like to say to all HSD(THS) divers that please try to learn how to drive your vehicle in city(below 42 mph).
It is your decision how to drive your car. You drive your car using your gasoline.
Again,I would like to say to all HSD(THS) divers that please try to learn how to drive your vehicle in city(below 42 mph).
It is your decision how to drive your car. You drive your car using your gasoline.
#46
06-04-2006, 06:21 PM
Re: How to calculate MPG
Originally Posted by CGameProgrammer
So you've figured out a way to accelerate in EV mode without doing it really really slowly, holding up traffic, pissing off tons of people, and increasing commute time?
- It is inefficient to accelerate slowly.
- It is inefficient to accelerate in EV mode.
- It is efficient to accelerate briskly.
- It is inefficient to accelerate with battery assist, please try to avoid using battery power.
Then please teach me. Also, I drove on the highway a long trip and got 39 mpg, but the EPA highway estimate is 38 mpg. I must have been doing it incorrectly; can you please teach me how to drive on the highway?
Also, please note that the EPA number is reduced by 22% from the actual test result.
Our recommendation for highway driving is shown following post.
https://www.greenhybrid.com/discuss/...67&postcount=3
Ken@Japan
Last edited by ken1784; 06-04-2006 at 06:23 PM.
#47
06-04-2006, 07:31 PM
Re: How to calculate MPG
Originally Posted by ken1784
We found that...
- It is inefficient to accelerate slowly.
- It is inefficient to accelerate in EV mode.
- It is efficient to accelerate briskly.
- It is inefficient to accelerate with battery assist, please try to avoid using battery power.
- It is inefficient to accelerate slowly.
- It is inefficient to accelerate in EV mode.
- It is efficient to accelerate briskly.
- It is inefficient to accelerate with battery assist, please try to avoid using battery power.
The EPA number can't be compared with real mileage. It is for comparison purpose between different vehicles.
#48
06-04-2006, 08:13 PM
Re: How to calculate MPG
Originally Posted by CGameProgrammer
I do all that, but you see, the TCH gets 2-10 mpg while accelerating at low speed. When I have to stop and go often and unexpectedly (like by traffic, or lights turning yellow/red right when I get near them) then mileage hurts alot.
Exactly. Usually, the difference between EPA and real-world is much greater for city driving than it is for highway driving. Someone might get 6 mpg worse than EPA city when city driving, but only 2 mpg worse for highway. So even if the EPA city score is 2 mpg higher than highway, that person would still do better on the highway than the city.
Exactly. Usually, the difference between EPA and real-world is much greater for city driving than it is for highway driving. Someone might get 6 mpg worse than EPA city when city driving, but only 2 mpg worse for highway. So even if the EPA city score is 2 mpg higher than highway, that person would still do better on the highway than the city.
Bob also reported that "The Prius has significantly better city performance than highway numbers."
http://home.hiwaay.net/~bzwilson/prius/#MPG%20Route
Anyway, I'm trying to be a kind of evangelist to tell people how to drive HSD(THS) vehicle collected by our know-how since 1997.
Ken@Japan
#49
06-05-2006, 06:56 AM
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Posts: n/a
Re: How to calculate MPG
"hand calculated" figures can be inaccurate (vary from the TCH's figures) the because the amount of fuel used will vary from tank to tank because of the pump shut-off variations.
True, but over time with many tank fillings, the error is small by hand calculating. That's why I'm not paying much attention yet to the milages on the data base as most are at 1 tank and on one tank you could be off by 1 or 2 mpg's with just a couple of squeezes of the pump. Also on that first tank you don't really know if it was full when the dealer gave you the car unless you went out and immediately topped off the car. That alone, even over 2700 miles could account for getting me over 38.
I calculated the other night that my average over 2700 miles would go up by almost 0.5 mpg (getting me over 38) with just 1 less gallon of gas. The pursuit of the "ultimate" number is not really profitable, simply fun.
True, but over time with many tank fillings, the error is small by hand calculating. That's why I'm not paying much attention yet to the milages on the data base as most are at 1 tank and on one tank you could be off by 1 or 2 mpg's with just a couple of squeezes of the pump. Also on that first tank you don't really know if it was full when the dealer gave you the car unless you went out and immediately topped off the car. That alone, even over 2700 miles could account for getting me over 38.
I calculated the other night that my average over 2700 miles would go up by almost 0.5 mpg (getting me over 38) with just 1 less gallon of gas. The pursuit of the "ultimate" number is not really profitable, simply fun.
