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Discussion Starter · #1 ·
I already wrote about what I think of the software in general, namely that it is not very user-friendly.
When it comes to the trip computer, I am at a total loss. Granted that I am on my first tank of gas, but the important readings (ave. MPG & miles to empty tank) make no sense. These readings are all over the map from 1 minute to the next. I read in the manual that the miles to empty tank is based on the fuel consumption during the last 20 miles driven!!! Seems to me that that is crazy. Even taking that into consideration, the readings still make little sense.

I would appreciate any feedback on this issue. BTW, I picked up the car with 10 miles on the Odometer & did a RESET immediately. Thanks in advance for any advice.
 

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You'll find differing opinions on here about the accuracy of the trip computer. Some report that it's dead on, others report it's optimistic (I've never seen anyone say that it's conservative). I've noticed my average consumption is usually about 1MPG optimistic (e.g., reads 20 average, but really getting closer to 19). Grab a Scangauge if you really want to get the most accurate results.
 

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I already wrote about what I think of the software in general, namely that it is not very user-friendly.
When it comes to the trip computer, I am at a total loss. Granted that I am on my first tank of gas, but the important readings (ave. MPG & miles to empty tank) make no sense. These readings are all over the map from 1 minute to the next. I read in the manual that the miles to empty tank is based on the fuel consumption during the last 20 miles driven!!! Seems to me that that is crazy. Even taking that into consideration, the readings still make little sense.

I would appreciate any feedback on this issue. BTW, I picked up the car with 10 miles on the Odometer & did a RESET immediately. Thanks in advance for any advice.
My understanding of the trip computer and the miles till empty is it calculates on the previous 20 miles driven. Mine seems to be fairly accurate.
 

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Discussion Starter · #4 ·
How can it be accurate (at least in my situation) if the "miles to empty" changes drastically & continuously with time driven? I'm at a loss!
 

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Well, obviously it will change based on whether you're flooring it off every stoplight or cruising at 60 on the highway. What are you confused about?
 

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I don't recall any reports here that the MPG reading is spot on, only that it's "optimistic". Mine is consistently 1.5 MPG optimistic.

If your engine is cold, as it is starting off on your morning commute the Mile To Empty will drop pretty quick as your MPGs is very poor at this time. Then as the engine reaches operating temperature and you start cruising on the highway you will notice the Miles to Empty slowly decrement or maybe not at all. This reading is constantly in flux as it should be to offer the most accurate distance to empty based on your current fuel consumption. I noticed the same effect on my previous VW and that trip computer was near perfection!
 

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Discussion Starter · #7 ·
Well, obviously it will change based on whether you're flooring it off every stoplight or cruising at 60 on the highway. What are you confused about?
I can be doing 60 MPH on the highway & the miles to empty can change drastically from time to time. In my world that makes little sense.

I was told by my salesman that this is not unusual when starting out with a new car but that after it achieves a proper reading, it kind of resets & all should then be OK. Not in my case! Having said that, I cannot imagine a scenario where miles to empty can be anywhere near accurate (since it is only based on last 20 miles driven) unless one is driving steadily for a long period of time. The computer cannot know what the driving conditions (fuel consumption) are going to be from 20 miles to another 20 miles.

What the computer should be doing is taking a reading ever so often (eg every 20 miles), storing that value, and then taking another reading (next 20 miles) and averaging the 2 readings. It should continue to take readings & taking the average all the way up to n readings. I don't think it is doing that (from what the manual says).
 

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It makes perfect sense. It's simple math. Example:

You begin your trip from your city garage, where you normally get 20 MPG. You have 20 gallons of gas in the tank. The trip computer calculates...

20.0 MPG x 20.0 Gallons of Gas = 400 Miles to Empty

On today's imaginary trip, you have spent 20 miles on the highway, where you are now getting 30 MPG. Since you were getting 30 MPG and you traveled 20 miles, you used 2/3 of a gallon of gas. You now have 19.3 gallons of gas in the tank. The trip computer now calculates...

30.0 MPG x 19.3 Gallons of Gas = 579 Miles to Empty

The way you want it to work would make it less useful to me. I live in a city/urban area and most of the time my average MPG is 19.0 - 20.0. When I take a long highway trip, the trip computer should adjust to tell me how much more gas I have on that trip, not how much further I would be able to go if I was back home in the city. It's just a fancy calculator built into your dashboard. You need to use your brain and look at the situation ahead of you and make your own judgement. The trip computer is there to provide you with some numbers which will help you make that judgement.

One thing that would be nice was if the computer used two different numbers, based on a more advanced model, and kept your average city MPG and average highway MPG and then showed you "Miles to Empty: Between x (city) and x (highway)." But as it is now, it does make sense. It's just doing very simple math.
 

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Discussion Starter · #9 ·
The way you want it to work would make it less useful to me. I live in a city/urban area and most of the time my average MPG is 19.0 - 20.0.
This does not work for me at all. I do a combination of city/urban and highway. My method would work better for me! A more advanced model is definitely needed. This could be achieved with a software update.
 

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Just use my method, when the gas gauge gets low, fill up :)
 

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Discussion Starter · #12 ·
Just use my method, when the gas gauge gets low, fill up :)
You forgot the end of your sentence: AND divide the # miles driven by the # gallons to fill up......

Having said that, the more I think about this joke of a trip computer, the more I just have to laugh.
This is the golden age of computing. All the trip computer does is divide the last 20 miles driven by the gas consumed. This is not "computing", it is arithmetic in its simplest form.

In 1980, using the ORIGINAL IBM PC, I designed a software program for a medical device which treated cancer with heat (500 KHZ Radio-frequency). The program monitored temperature at different locations in the tumor & fed back the data to regulate the power being delivered to the tumor.

Today, there are software programs being used to "teach" a user's habits. Example, voice recognition. This could be used to "teach" a driver's driving habits over time. In any case, a somewhat simple algorithm could be used to do a much better job than is currently being done (example, the algorithm I suggested earlier in this thread).

Hopefully, Volvo will get with the program (although I'm not holding my breath). I need to find who to write to at Volvo.
 

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You forgot the end of your sentence: AND divide the # miles driven by the # gallons to fill up......
Yes...because those are the hardest things nowadays: multiplication and division.

Having said that, the more I think about this joke of a trip computer, the more I just have to laugh.
This is the golden age of computing. All the trip computer does is divide the last 20 miles driven by the gas consumed. This is not "computing", it is arithmetic in its simplest form.

In 1980, using the ORIGINAL IBM PC, I designed a software program for a medical device which treated cancer with heat (500 KHZ Radio-frequency). The program monitored temperature at different locations in the tumor & fed back the data to regulate the power being delivered to the tumor.
I bet you that the '80 ORIGINAL IBM PC was not able to stop your car if it saw a pedestrian in front. Nor could it play an mp3, nor could it do various other stuff that our mighty Volvo can.

Today, there are software programs being used to "teach" a user's habits. Example, voice recognition. This could be used to "teach" a driver's driving habits over time. In any case, a somewhat simple algorithm could be used to do a much better job than is currently being done (example, the algorithm I suggested earlier in this thread).
Hopefully, Volvo will get with the program (although I'm not holding my breath). I need to find who to write to at Volvo.
What you, my friend, are forgetting is that *no* drive is the same. None. Even if you were driving the exact same way all the time, traffic in its dynamic nature cannot be predicted. You surely must see that. One day you're in a traffic jam and one day you're not. Your driving style does not change but the mpg surely will. What would you have the computer learn?
And that's assuming that your driving style stays constant.

Also, the car *is* learning your habits and applying what it learned where it can - like the gearbox deciding when to upshift or when to hold a lower gear, for example.
It also learns and adjusts on the type of gas you put in. And probably other stuff that we don't know
 

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I hate how the trip computer doesn't have the S70's trip computer, where the trip goes to over 1000km.

Regarding the MPG, the trip computer in my S60 is optimistic by about 0.5L/100km to 1L/100km.

Distance to empty is well, always an estimate as it depends on your driving style and where you're doing the driving. I always take it with a grain of salt unless I have the low fuel warning light on.
 

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Discussion Starter · #15 ·
So, yesterday I'm driving on Rte #1 on a 3 mile stretch doing 45-55 mph. I maybe stopped at 1 light. During this stretch, the MILES TO EMPTY went (in order) from 80 --> 100 --> 90 --> 105 --> 85. Does this make any sense?
 

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In almost 10 years of being on this forum this is hands down the best thread I've ever read. Thanks for continuing to keep it going. I don't know. Sounds like a pretty serious problem. Maybe take the car back and ask for a refund?
 

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John, that's pretty simple and it makes perfect sense. It means, "You have somewhere between 80 and 105 miles to empty depending on how you drive. If you plan on going more than 80 miles, you should probably get some gas. If you plan on going more than 105 miles, you should definitely get some gas." It doesn't mean, "While you were driving, your car has now manufactured enough gasoline to go another 20 miles!" "Oh, wait, I spilled some of that gas I made, now we can only go 90." "Good news, everyone! I made even more gas and now we can go 105!" No. It doesn't mean that. Though my girlfriend and I had a great conversation in the car last weekend about how amazing it would be if cars could suck emissions out of the air, use a negative energy machine, and convert those emissions to more gasoline.
 

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Discussion Starter · #19 ·
To: DWBF1 & matt1122

You can make as much fun of me as you are free to do, but as someone who knows computing, it makes no sense (given that the Trip computer makes its calculations based on the last 20 miles driven) that the MILES TO EMPTY would change by up to 25% over a distance of 3-4 miles driven at an almost constant speed of 45-55 mph. Cheers.
 

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How about contacting someone at Volvo to answer these questions? My quick Google searching has turned up quite a few Volvo software engineers; surely some of them are contactible in some sense.

(It'd be a lot easier if I had some understanding of the corporate structure; a web developer wouldn't be much help when we need the guy who wrote the actual trip computer software.)
 
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