Tips Pls On Tracking Fuel Consumption

[ALNewOwner]

Hello, I just took delivery of a 2007 Prius and am very happy with it so far.

I'd appreciate some tips on how best to track fuel consumption.

I realise that the 'Consumption' screen is one method I can use, and I've worked out how to use the reset button to start a new measurement for the journey I'm on, so that's fine.

However, I've read at least one web newspaper article where someone (in the UK) has run a concurrent second (and maybe third?) average consumption measure, meaning you can, for example, run one that lasts from when you take delivery of the car, and then another for the particular journey you're on.

And on page 147 of my Owner's Manual, it says the following when talking about the Odometer / Trip meters that you see near the speedometer just under the windscreen (ie not on the display in the middle of the car's dashboard). I've 'emboldened' the important bit...

Quote...

This meter displays the odometer and two trip meters.

1. Odometer - Shows the total distance the vehicle has been driven.

2. Two trip meters - Show two different distances independently driven since the last time each trip meter was set to zero.

You can use one trip meter to calculate the fuel economy and the other to measure the distance on each trip. All trip meter data is canceled if the electrical power source is disconnected.

... End Quote

Now perhaps this means that you set one odometer to zero when you fill up the car (tricky to gauge exactly how much you've got in there), and then run the fuel to zero (a bit risky) and work out mpg.

But alternatively, I'm wondering if there's just some functionality of which I'm unaware.

Any thoughts on that particular point, or on the general issue of how to have different mpgs being calculated simultaneously would be much appreciated.

Many thanks, Adam

[hertsnminds]

Not sure if its the same on a Prius but on the verso you have

Odomoter (miles since new)

Trip A

Trip B

Trip A and B can be manually reset by you any time you like, (not sure if they have a max they will run to).

To calculate fuel usage just divide the difference in odometer readings (between fill ups) by the amount of fuel you put in.

e.g.

Odometer reads 100 miles

You put 50 litres on the tank

Next time you fill up

Odometer reads 600 miles

You put 40 litres in the tank

MPG = (600 (Odo 2) - 100 (Odo 1)) / ((50 (litres) / 4.546 (conversion to gallons))

= 500 / 10.998

= 45.46

[gniie]

Not sure if its the same on a Prius but on the verso you have

Odomoter (miles since new)

Trip A

Trip B

Trip A and B can be manually reset by you any time you like, (not sure if they have a max they will run to).

To calculate fuel usage just divide the difference in odometer readings (between fill ups) by the amount of fuel you put in.

e.g.

Odometer reads 100 miles

You put 50 litres on the tank

Next time you fill up

Odometer reads 600 miles

You put 40 litres in the tank

MPG = (600 (Odo 2) - 100 (Odo 1)) / ((50 (litres) / 4.546 (conversion to gallons))

= 500 / 10.998

= 45.46

I agree with your method. I use it myself. A small correction is that in your calculation example you should use 40 lt and not 50 lt to get an accurate reading.

Another small observation is that filling your tank is also vary with the temperature of ambiant environment(outdoor temp). It can increase or decrease the volume of the tank pending on high or low temp. ( is probably a small procentage but it can differ from your onboard computer).

Hope I didn't misslead anyone if I am wrong.

Ta ta

[ALNewOwner]

Thank you both for your thoughts, I'll give that a go...

[hertsnminds]

I agree with your method. I use it myself. A small correction is that in your calculation example you should use 40 lt and not 50 lt to get an accurate reading.

my mistake, you are correct it has taken the 40 litres to get from fill up 1 to fill up 2.

The only other thing to say is make sure you always fill up in the same way. e.g. stop after the same number of times the pump shuts off or always brim the tank. If you brim it on the first fill but not on the next you will not get an accurate calculation.