My fuel economy master equation

[alpha754293]

Tip #1

Calibrate your speedometer/Odometer. There is a new pinned topic regarding this.

 

Tip #2

Calibrate your fuel fills. Also covered under the same topic.

 

Once you know how much gas it takes from the same pump after 3 fills, and know exactly the variance in your Odometer, then you can precisely calculate how much fuel you are actually using, and ignore the general purpose trip meters. They are there only to serve as a general guide to how the car is doing and are not accurate except in a general manner. Only precise instrumentation on the car will give you true results, and I dont think any of us want to hang $1000's in equipment on our cars just to find out how many actual MPG it gets.

 

Tip #3

Don't use MPG, but use gallons used instead. How many gallons of fuel did you consume this month in this car, that you would have used in your other car. Look at the bigger picture instead of the smaller one. Compare my Flex to the HyTi, Both go roughly the same distance on a tank, but the Flex holds nearly 5 more gallons of fuel. Go 1000 miles and see how many more gallons the one uses over the other, then you will get the bigger picture, wow it cost me XX more to drive this one vs the other one the same distance.

 

Well...you can do the calculation both ways right. It's like that with any data really - that one should look at it both in terms of the "local" effect and then the "global" effect. It's why for statistics, it's equally important to look at the absolute values as well as the percentages because either piece of information by itself is not enough to tell the whole story, but together; it gives meaning to each other and broadens the framework and frames the discussion in a totally different way. That approach basically works for anything/everything.

 

And sometimes, it's also important to read about and find out how such data/statistics were collected as well (since sometimes, the "how" question is just important as the "what/why" questions as it is just as important as the result arising from those questions.)

 

So having said that, the "small" picture is just as important as the "big" picture. Your instantaneous, trip average, running average, on-road average, and lifetime average fuel economies all matter at varying levels. (It's why when people ask me about what I think about my FFH, I tell them that my current lifetime running average fuel economy is 37.8 mpg (according to the trip computer).) If you can hit 50s, the next question is can you keep it that way.

 

And what's interesting about this is that our Group Vice President of Global Product Development, Raj Nair, (while commenting about the C-MAX Hybrid EPA Monroney label downgrade to 43 mpg combined) said that on a 100-mile trip, it only works out to be like 0.2 gallon difference. So, people were making it like it's such a big deal and if you read people's comments throughout the internets, some were saying that we're lying and stuff - but when you frame it in that way where that 4 mpg difference equates to 0.2 gallon actual different per 100 miles; it's interesting to see how people's way of thinking just like "clicks" and switches to an entirely different mindset. (People are interesting that way...)

 

So I use both numbers actually. I track the fuel consumption (at the pump, which btw, also varies too cuz not all pumps are the same, and the auto-shut off doesn't always really quite work like it should) on Fuelly, while at the same time, I let the vehicle trip computers calculating running averages (and displays the instantaneous) as well.

 

if you ignore the "little bits", eventually, a LOT of "little bits" add up to being a LOT. And then it's like..."what the heck happened?"

 

Besides, I also use the "little bit" (the mpgs) to plan when I fill up (and where) so that it's most cost effective. (Yeah, it's like I have pure EV habits, even driving a non-plug-in hybrid.)

 

Whoa firstly do you work for Ford? in that case Good for you.

 

And don't get me wrong when said it was a 'clever trick'. I meant that some owners are under impression that when it shows 0.0 g consumed rather that 0.09 g consumed. They assume its all electric no gas was used, and do not realize that they are seeing a 'truncated' number and not a 'rounded' number ( which would be more accurate representation) in this example would be 0.1 g. This issue threw my charts for a few days till it occured to me how to figure out actual gas consumption.

 

 

Wow great tips on measuring fuel consumption thanks to you and Acdii. Mine is poor-man's way take pics of trip summary and adjust each tank fill if there's variance. So it's more like mpg snapshot of my day to day commute.

 

I believe for summer numbers and relatively new guages its been very close. May be a slight bit off as my calculated gallons consumed vs actual fill is usually less by about +5 to +7% (about 0.7 g per 10 g fill) at the pump. Not sure if that's due to evaporation from the tank, pump calibration or gauge issue, or the mpg number not being accurate (truncated) like gallon number. I consider this as just a small factor.

 

I just saw the note about being on fuel economy team. Sure, if the pay/benefits are good why not. I'm open for being a consultant. I'll keep that in mind. Thanks.

 

Yes sir. (see my disclaimer in my signature). I'm a Global Core Weight Engineer, so my day job actually has very little to do with fuel economy. I only pay attention to it cuz I put ~40,000 miles/year, so it's kinda nice that I don't have to spend quite nearly as much on fuel.

 

If you are relatively tech-savvy, you can actually develop your own app on either an Android device (I think you MIGHT be able to do it with iOS devices as well, but I haven't seen any demonstrations of that - most demos I've seen are with Android-powered devices) where you built (or buy) your own CAN bus reader/translator and then using the app development kit; you can read out a LOT more information than what your IP cluster shows you (via the OpenXCPlatform @ http://openxcplatform.com/).

 

For a couple hundred bucks, you can get yourself basically a 10.1" "IP cluster" and that can probably give you the information that you are really looking for and in greater detail (I would think). It's like the ScanGaugeII; except that you develop your app to suit your needs. Plus, then you can show your friends (if you have the tablet mounted on the center console) and be like "check THIS out!" .... "can your car do that?" :D

 

re: measuring fuel consumption

well...it depends on what level you want to take it to, right? And because a lot of my drives are typically longer, so the first decimal place is enough precision for me. But if you do a lot of city trips, (or enough of them), then that level of precision might not be sufficient for you.

 

re: fuel economy engineer

If you have the qualifications and credentials, and you're serious and interested, I strongly suggest you stop off at careers.ford.com. (Sorry for the sales pitch. haha...never thought myself as much of a "car salesman" or for the car company). But there's a lot of really cool stuff that we're doing here. (2014 Honda Accord Hybrid EPA numbers were just published yesterday. It'll be interesting to see whether they run into the same types of teething pains we were seeing earlier this year.) (Actually, if you search for "fuel economy" for experienced professionals, there are quite a number of positions that are open. It's nice to be leading/being a leader for a change and pushing the envelop. Even *I* can't believe that we're second (behind Toyota) in hybrid sales. Like...wow. That's fantastic news for us!)

 

(Sources: http://automobiles.honda.com/accord-hybrid/

http://www.thedetroitbureau.com/2013/08/ford-trims-c-max-mileage-by-10-offers-goodwill-cash-to-owners/

http://detroit.cbslocal.com/2013/06/02/ford-hybrid-vehicle-sales-break-full-year-record-in-first-five-months-of-2013/)

Edited September 25, 2013 by alpha754293

[majorleeslow]

Maybe we would see that some of the higher MPG # while temps being are related to either short or longer trips compared to the one right next to it.

 

So I wasn't able to create a chart with Temp and Distance showing mpg. But here's a file that shows green for everything above 50mpg and Red for below that number.

I chose the 50 mpg as my fuel gage is showing a slight variance that I discovered lately. about 5-7%.

 

Sorry if its too complicated to read through but thats the simplest way to show that the shorter trips had bad mpg and high temp trips had more bad mpg's than that of low temp (bottom right).

 

You may need to save it on your computer to view it.

 

Edited September 26, 2013 by majorleeslow

[corncobs]

Cool thanks for all this work it looks really interesting. I will take a look tomorrow when I have a PC in front of me right know you are right I can't see much.

[majorleeslow]

 

re: fuel economy engineer

If you have the qualifications and credentials, and you're serious and interested, I strongly suggest you stop off at careers.ford.com. (Sorry for the sales pitch. haha...never thought myself as much of a "car salesman" or for the car company). But there's a lot of really cool stuff that we're doing here. (2014 Honda Accord Hybrid EPA numbers were just published yesterday. It'll be interesting to see whether they run into the same types of teething pains we were seeing earlier this year.) (Actually, if you search for "fuel economy" for experienced professionals, there are quite a number of positions that are open. It's nice to be leading/being a leader for a change and pushing the envelop. Even *I* can't believe that we're second (behind Toyota) in hybrid sales. Like...wow. That's fantastic news for us!)

 

My experience with Honda car few years ago was very good. I drove it very rash much more than any other cars and it met the window sticker even in cold temps. But back then the Ethanol allowed wasn't 10% legally. I think that was a big factor. But it was one reliable little car. Unfortunately it drowned in a flood and was a total loss. But lately they're sacrificing Fuel economy for more HP and the price is too high with lesser features than other cars. Not sure how it will do against the Korean brands.

 

It would be interesting to see if they have issue with meeting the window sticker.

Edited September 26, 2013 by majorleeslow

[majorleeslow]

Cool thanks for all this work it looks really interesting. I will take a look tomorrow when I have a PC in front of me right know you are right I can't see much.

 

I don't know how to share may be throw it on a file cause I sure can't see anyting. Believe me I've tried a few ways but all of them shrink the image.

 

 

So I hope this zip version works.

 

temp-mpg.zip

[alpha754293]

 

My experience with Honda car few years ago was very good. I drove it very rash much more than any other cars and it met the window sticker even in cold temps. It was one reliable little car. Unfortunately it drowned in a flood and was a total loss. But lately they're sacrificing Fuel economy for more HP and the price is too high with lesser features than other cars. Not sure how it will do against the Korean brands.

 

It would be interesting to see if they have issue with meeting the window sticker.

 

Yeah, it's a bit of a paradox when you really think about it. Toyota might have actually been one of the first to start that - cuz when they first launched the Prius in North America, a lot of people laughed at it. (A lot of people still laugh at it, albeit probably for different reasons). Second and third gen have more power than the first gen Prius and I think that the reality is that in the North American market; people are still very much concerned about power - even on ecoboxes. [to someone that owns a Prius] "How much does your car have?" [if it were me thinking...] "does it matter/who cares???" but people still ask. Actually when I took my Fusion out to the track day with the Shelbys, some people DID ask me how much power/torque the engine/electric motor has. Part of it is the culture, but part of it is also like kinda knowing "when" to ask. (Considering the Japanese street racing scene, they're not exactly all econoboxes either; and they have a thirst for power just like any other. But I would be surprised if the Japanese people bother to ask how much power a Prius has (or some of their smaller city cars).) Course, one could also argue that our roads and the way we drive is very different as well, and that's also very valid, but power and fuel economy often are polar opposites as a competing force.

 

Which is also why when the 3rd gen Prius came out and it hit the magical 50 mpg combined - that was a HUGE deal.

 

I LOVE it when they're now having a full on mid-size sedan fuel economy war. This is awesome!

[majorleeslow]

You are absolutely right. Everyone likes to have just that little extra power for their mpg target. Which was the major factor in me buying the fusion rather than the Prius. this is bcauz they are already used to the lower fuel economy from past owned cars.

 

But if you ask me now if i'll go back to a lower mpg car, I'll surely think about it a 1000 times. Most likely say no to lower mpg. One just gets used to it..

Edited September 30, 2013 by majorleeslow

[alpha754293]

You are absolutely right. Everyone likes to have just that little extra power for their mpg target. Which was the major factor in me buying the fusion rather than the Prius. this is bcauz they are already used to the lower fuel economy from past owned cars.

 

But if you ask me now if i'll go back to a lower mpg car, I'll surely think about it a 1000 times. Most likely say no to lower mpg. One just gets used to it..

 

The only way I might go do a slightly lower mpg car is if I was switching out my FFH for a Fusion Energi PHEV. It's EPA rating is lower than the FFH, but if I can drive 21 miles on all electric (my commute to work is only 15 miles), so it might be worth it. But it also costs quite a bit more than my FFH does already.

[murphy]

It's been almost 6 months since I got my Energi. I've burned about 4 gallons of gas in that time. One 35 mile destination and one 20 mile destination. All of the rest has been local destinations of 11 miles or less. If it wasn't for two 260 mile trips in November and December I could probably go a year on the original tank of gas.

[majorleeslow]

Its inedible that you only fill single digit in months. However what made you but Energii instead of the volt which comes out much cheaper after the rebate and has longer range?

 

For me having the 5th seat is a big factor. And don't have the extra$$$ to throw at it.

 

Just curious.

[murphy]

Price does not enter into my decisions any more. I spent enough years being frugal. Now I buy what I want. My first car was a Ford, the next two were Plymouths, all of the rest have been Fords. A long time ago I worked for Philco-Ford, which no longer exists, so my leaning is toward Ford. I have never owned any other brand.

The electric range of the Volt would make no difference since I don't need that distance for my usual driving. I looked at the Tesla but they are way behind their stated plan for building a charging infrastructure.

 

It's not a rebate, it's a tax credit. It your tax bill at the end of the year is less than the tax credit you don't receive all of the tax credit.

[alpha754293]

It's been almost 6 months since I got my Energi. I've burned about 4 gallons of gas in that time. One 35 mile destination and one 20 mile destination. All of the rest has been local destinations of 11 miles or less. If it wasn't for two 260 mile trips in November and December I could probably go a year on the original tank of gas.

 

That's awesome!

 

Price does not enter into my decisions any more. I spent enough years being frugal. Now I buy what I want. My first car was a Ford, the next two were Plymouths, all of the rest have been Fords. A long time ago I worked for Philco-Ford, which no longer exists, so my leaning is toward Ford. I have never owned any other brand.

The electric range of the Volt would make no difference since I don't need that distance for my usual driving. I looked at the Tesla but they are way behind their stated plan for building a charging infrastructure.

 

It's not a rebate, it's a tax credit. It your tax bill at the end of the year is less than the tax credit you don't receive all of the tax credit.

 

Price still factors into my calculations (I wished that I was already at the state where price didn't factor in being in my early 30s) haha...

 

And the remark about it being a tax credit is so true! Which, BTW, for me as a Canadian, I don't get it unless I can talk someone into buying one for me in the States (due to residency restrictions).

[murphy]

 

Price still factors into my calculations (I wished that I was already at the state where price didn't factor in being in my early 30s) haha...

 

Save as much money as you can for the next 30 years and you can get there.

In my case that included buying a new car about every 10 years.

:)

[alpha754293]

Save as much money as you can for the next 30 years and you can get there.

In my case that included buying a new car about every 10 years.

:)

 

Yeah...it's easier said than done though.

 

The current plan is that I'm going to be replacing my current FFH with a PHEV in 10 year's time. By then, of course, who KNOWS what technoolgy will be available.

[majorleeslow]

Price do not enter into my decisions any more. I spent enough years being frugal. Now I buy what I want. My first car was a Ford, the next two were Plymouths, all of the rest have been Fords. A long time ago I worked for Philco-Ford, which no longer exists, so my leaning is toward Ford. I have never owned any other brand.

The electric range of the Volt would make no difference since I don't need that distance for my usual driving. I looked at the Tesla but they are way behind their stated plan for building a charging infrastructure.

 

It's not a rebate, it's a tax credit. It your tax bill at the end of the year is less than the tax credit you don't receive all of the tax credit.

Good for you, it would be nice to be able to do that.

 

Regarding tax credit, I don't believe that's true. You get the full tax credit (thanks) as long as your vehicle falls under the maximum units allotted for tax credit.

 

I definitely think its a direct credit and has nothing to do with how much one owes.This is just a way of the govt to say thanks for being the beta tester... :)

 

But this discussion is for a separate topic. And i'm by no means a tax advisor.

Edited October 8, 2013 by majorleeslow

[alpha754293]

Good for you, it would be nice to be able to do that.

 

Regarding tax credit, I don't believe that's true. You get the full tax credit (thanks) as long as your vehicle falls under the maximum units allotted for tax credit.

 

I definitely think its a direct credit and has nothing to do with how much one owes.This is just a way of the govt to say thanks for being the beta tester... :)

 

But this discussion is for a separate topic. And i'm by no means a tax advisor.

 

Umm...dunno about that. Tax credits usually work if there's enough income for the tax credit to work with/against. It's ESPECIALLY useful if you owe the government money (i.e. tax due > tax paid to date at the end of the year).

 

As an example, I'm a single male working in Michigan, but living in Ontario. So, I don't have resident taxes that are due, but standard Michigan state, US Federal, Medicare, and Social Security are all deducted. And then I take the standard deduction because an itemized deduction is actually worse for me. And then on the Canadian side, because all of my income is "foreign" income, so I get full credit for it, which means that I have no Canadian income, and therefore; nothing to deduct tax credits against.

 

It's a bit off-topic, but it's (I think) VERY relevant because it's important that people know and understand how the tax credit is going to work in THEIR situation; which if you read all of the news articles about it and stuff, and people's comments, you'd think that it's like an automatic given. And I'm not so sure that it is. I'd probably have to read more about how you'd actually go and claim that, but the best bet is probably to consult a tax advisor to get a professional's advice.

[hybridbear]

Regarding tax credit, I don't believe that's true. You get the full tax credit (thanks) as long as your vehicle falls under the maximum units allotted for tax credit.

 

I definitely think its a direct credit and has nothing to do with how much one owes.This is just a way of the govt to say thanks for being the beta tester... :)

 

But this discussion is for a separate topic. And i'm by no means a tax advisor.

Alpha is correct. To qualify for all of the C-Max Energi $4007 tax credit you must have enough income to owe $4007 in federal income tax after all your other deductions and credits. The tax credit can lower your federal tax burden to $0 for that tax year but it cannot make it negative. And from what I've read it appears that there is no way to split the tax credit over multiple years. This is why my parents are taking extra withdrawls from their 401k plans this year so that they have enough income to take advantage of the entire tax credit. Since all year they've been paying taxes on their Social Security income this means that they'll get back as a refund basically all of the taxes they paid in 2013. My goal is to calculate the income they need so that they don't withdraw more than needed and can get their 2013 tax burden as close to $0 as possible while still taking advantage of the entire credit.

 

Either way... :backtotopic:

[majorleeslow]

Alpha and HB, that does make sense. One would think guys who end up buying a plug-in usually (almost all the time) owe more than that.

 

On the topic again.... my car does not like temps under 50 my mpg is very difficult to keep over 50. plus my trips got shorter avg around 10 mi. which is also showing on my avg number. :(

 

I did finalize on an equation that good for stats, one that gives me the exact mpg impact from each trip I take. Can share that if anyone's interested.

 

BUT still haven't found a good solution for SOC.

Edited October 17, 2013 by majorleeslow

[hybridbear]

Alpha and HB, that does make sense. One would think guys who end up buying a plug-in usually (almost all the time) owe more than that.

 

On the topic again.... my car does not like temps under 50 my mpg is very difficult to keep over 50. plus my trips got shorter avg around 10 mi. which is also showing on my avg number. :(

 

I did finalize on an equation that good for stats, one that gives me the exact mpg impact from each trip I take. Can share that if anyone's interested.

 

BUT still haven't found a good solution for SOC.

The under 50^oF weather is impacting us too.

 

I'm interested to see your updated equation.

[acdii]

The under 50^oF weather is impacting us too.

 

I'm interested to see your updated equation.

Same here, it was 45* and I only managed 44.3, its also misty wet too, so that didn't help.

 

 

 

Still better than 34!!! :happy feet:

[majorleeslow]

Same here, it was 45* and I only managed 44.3, its also misty wet too, so that didn't help.

 

 

 

Still better than 34!!! :happy feet:

 

Or 21 for the gassolilic Fusion.

[acdii]

Made a new grill cover today, so we shall see if it helps with temps being cold next week.

[alpha754293]

I think that the hardest part about it being cold isn't the car. It's ME! lol.... brrrrr. It's hard to drive when it around 1 or 2 C (34-36 F) in the mornings. Between the windows fogging up and my freezing my butt/hands off...it's like I need the heater on, which of courses, takes the fuel economy down.

 

And it'll be a different story once I put the winter tires on too (because the factory stock tires on the 18" aluminum wheels start off with only 10/32" tread depth, which isn't a lot at all), and I don't want to take the unnecesary risk of trying to drive with that in the winter even though they're supposed to be rated all seasons (M+S).

 

But it doesn't appear that my fuel economy numbers are dropping down as low as 35 mpg average.

[acdii]

The grill covers and cold weather are working. Even with the heat on I am still staying above 40. I do need to work more at it to stay above 44, but even when I dont, 43 isnt bad at all. I just wish the windshield would stop fogging up, thats what brings the MPG down.

[majorleeslow]

Hi everyone.. long time no msg.. been busy with stuff. finally got around getting back.. wanted to post this updated mpg averages I've been getting over the different temparature ranges.

 

hope it gives you some more understanding.