How To Calculate Your Car's Fuel Economy?


Joined
Jan 31, 2012
Messages
1,078
Likes
186
Location
Delhi
Re: How to Calculate Your Car's Mileage?

IMO tank full to tank full method is the best and reliable kindly follow the below mentioned steps for the same:

1) Fill your tank till auto cutoff
2) Set your trip meter to zero
3) Drive around for couple of days (routine one for daily average fuel consumption)
4) Fill the tank from same pump and if possible same machine till auto cutoff
5) Calculate the fuel consumption using your trip meter data and total fuel filled data shown on the dispensing unit.

I hope you find it helpful.

Regards
 
Joined
Aug 2, 2011
Messages
1,228
Likes
440
Location
Bengaluru
Re: How to Calculate Car's Fuel Efficiency?

How can i calculate mileage without using Full to Full method?
Sorry Aneesh. Tank-to-Tank is the best and must say, only possible method to calculate the FE. This is again subject to errors, which are negligible compared to any other method.
 
Joined
Jun 22, 2011
Messages
321
Likes
7
Location
Pune
Re: How to Calculate Your Car's Mileage?

Best Way to use Tank -to- tank or you can call Top to Top method.
Subdivided to

A. Stop filling fuel when sensor in the dispensing pipe feels the fuel the mechanism automatically shut the supply.

B. Stop the dispensing fuel when you visibly see fuel in pipeline of the car.

C. Wait for some times let the fuel bubble settle and again fill fuel.

In above methods I have observed the about 4~5 lts difference though it’s called full tank.
When I got thuck sound of automatic dispenser fuel and reading was approx 32ltrs.
When I see the fuel reaching to border of pipeline reading was close to 37.
After settling the bubbles again filled final reading touched 40 ltrs.
I prefer B method coz observed the silage of fuel in C method.


Always refuel your car at defined fuel station then you will reach to closest figure. It has been observed that fuel dispensing nozzles have no consistency in length and diameter.
 
Joined
Sep 1, 2010
Messages
1,572
Likes
80
Location
Mera Bharat Mahaan
Re: How to Calculate Your Car's Mileage?

Always refuel your car at defined fuel station then you will reach to closest figure. It has been observed that fuel dispensing nozzles have no consistency in length and diameter.
What difference it is going to make, if the diameter is different or length for that matter ?[confused]
 
Joined
Jun 22, 2011
Messages
321
Likes
7
Location
Pune
Re: How to Calculate Your Car's Mileage?

If dispenser length is more earlier cut off and length is less late cut off of fuel supply.
Earlier cut off is less fuel input in tank
Late cut off means more fuel in tank.

Below picture these have a feature of Auto-cut with various length and diameter.
 

Attachments

Last edited:
Joined
Oct 23, 2009
Messages
9,165
Likes
329
Location
Chennai
Re: How to Calculate Your Car's Mileage?

The float mechanism in the fuel gauge will not be accurate always. Especially when it is near the full tank mark. you can notice sudden drop once the needle crosses the half way mark (when on its way to empty). This has a resistor setup controlling the needle movement and always it can be an approximate value only.


Exactly! My car will run for 350KMS in the first half of the tank. In the second half the meter will drop rapidly and i will have to re-fuel around 450-500KMS depending on the conditions.


@ Powerpacked That is why i always follow the first method which you have mentioned. In the second method itself i notice spillage of fuel.
 
Joined
Jun 22, 2011
Messages
321
Likes
7
Location
Pune
Re: How to Calculate Your Car's Mileage?

Yes cooldhaya,
A. Stop filling fuel when sensor in the dispensing pipe feels the fuel the mechanism automatically shut the supply.
To achieve more accurate results this from this method you need to keep other parameters constant same fuel station & same fuel dispenser.

B. Stop the dispensing fuel when you visibly see fuel in pipeline of the car.
This method can be followed at various fuel stations with all kinds of dispensers. Which gives little relaxation as fuel difference is 3-5 ltrs. And that should be always kept in mind for calculation of Mileage.
 
Joined
Dec 24, 2011
Messages
115
Likes
23
Location
Thiruvanathapuram
Re: How to Calculate Your Car's Mileage?

One problem with tank to tank method.. Lets say you fill close to 45 ltrs on a tank full and your average consumption is about 2 litres daily.

It will need another 15-20 days for you to refill within which you will undergo a longer time in idling. This will have impact on the calcualtion and may give a feel that your car is giving lesser than what you expect.

This is just an example to highlight the fuel loss on idling factor.
 
Joined
Oct 20, 2011
Messages
194
Likes
2
Location
Bangalore/Chennai
Re: How to Calculate Your Car's Mileage?

I dont know if it out of topic, how do we check FE for LPG driving?
I assume you are asking for LPG tank mileage. Fill the LPG tank full(this would be known from the pressure gauge). Set trip meter to zero. Use only LPG for driving. When its over fully note down the Kms and drive with petrol.
Mileage = no. of kms / LPG tank capacity lt or kgs [kms per kg or km per ltr]
 
Joined
Jan 31, 2012
Messages
1,078
Likes
186
Location
Delhi
Re: How to Calculate Your Car's Mileage?

I assume you are asking for LPG tank mileage. Fill the LPG tank full(this would be known from the pressure gauge). Set trip meter to zero. Use only LPG for driving. When its over fully note down the Kms and drive with petrol.
Mileage = no. of kms / LPG tank capacity lt or kgs [kms per kg or km per ltr]
Else you can use tank full tank full method for LPG too get the tank full of LPG, set the trip meter to zero and run around for couple of days and then select the same LPG pump and if possible same timing for filling LPG again to match the exact pressure note down total KG of LPG consumed and from trip meter total KM run divide them, you will get the average LPG consumption per kg.
 
Joined
Feb 8, 2012
Messages
17
Likes
0
Location
Chennai
Re: How to Calculate Your Car's Mileage?

Best Way to use Tank -to- tank or you can call Top to Top method.
Subdivided to

A. Stop filling fuel when sensor in the dispensing pipe feels the fuel the mechanism automatically shut the supply.

B. Stop the dispensing fuel when you visibly see fuel in pipeline of the car.

C. Wait for some times let the fuel bubble settle and again fill fuel.

In above methods I have observed the about 4~5 lts difference though it’s called full tank.
When I got thuck sound of automatic dispenser fuel and reading was approx 32ltrs.
When I see the fuel reaching to border of pipeline reading was close to 37.
After settling the bubbles again filled final reading touched 40 ltrs.
I prefer B method coz observed the silage of fuel in C method.


Always refuel your car at defined fuel station then you will reach to closest figure. It has been observed that fuel dispensing nozzles have no consistency in length and diameter.

Tankfull to Tankfull will give you some how accurate FE of the car.

1) Fill the fuel to the tip of the fuel pipeline, as you mentioned in "c".

2) Reset the trip meter to zero.

3) Take a short drive for 15 mins, (or) say around 15 to 20 kms, and return to the same bunk and fill the fuel from the same filling point as mentioned in 1st line.

( I suggest short trip because,the fuel density plays major role in fuel refilling, the fuel density will not change with in short time. If you refill after a day or two definitely it will change. Moreover our driving style will not vary that much in a short span of drive, somebody will push the car hard acceleration to reach office in the morning and the same person will drive in relaxed mood in the evening. Our mind set also reflects in our driving, so I prefer short span of drive will give somehow accurate FE of the car.)

4) Now calculate the FE = total trip kms/fuel added in second filling.
 

sethumurugan

Honoured Member
Joined
Feb 8, 2011
Messages
3,837
Likes
1,162
Location
Chennai
Re: How to Calculate Your Car's Mileage?

Else you can use tank full tank full method for LPG too get the tank full of LPG, set the trip meter to zero and run around for couple of days and then select the same LPG pump and if possible same timing for filling LPG again to match the exact pressure note down total KG of LPG consumed and from trip meter total KM run divide them, you will get the average LPG consumption per kg.
I assume you are asking for LPG tank mileage. Fill the LPG tank full(this would be known from the pressure gauge). Set trip meter to zero. Use only LPG for driving. When its over fully note down the Kms and drive with petrol.
Mileage = no. of kms / LPG tank capacity lt or kgs [kms per kg or km per ltr]
I would like to bring to your notice that the user manual of my car says that i should fill LPG only upto 75% not full. So from then on am doing the same.

And more over, I do not know how to know whether the tank is full or not? if you mean by presure gauge, does is it mean in the car or LPG dispensing unit? If you mean by LPG dispensing unit, I do not remember seeing anything like that. I will do a check when I visit next time for filling LPG.

If you mean in car, I do not have such one in my car. Instead it has three LED which denotes the level of LPG. So I do not know how I have to fill full tank.

As of now I am filling LPG 10 ltrs every time and reset the trip meter. When the LPG is over, automatically I will get a beap and it will get switch over to petrol. At that time I will note down the trip meter and find the KM run and calculate the milage.
 
Joined
Oct 20, 2011
Messages
194
Likes
2
Location
Bangalore/Chennai
Re: How to Calculate Your Car's Mileage?

I would like to bring to your notice that the user manual of my car says that i should fill LPG only upto 75% not full. So from then on am doing the same.

And more over, I do not know how to know whether the tank is full or not? if you mean by presure gauge, does is it mean in the car or LPG dispensing unit? If you mean by LPG dispensing unit, I do not remember seeing anything like that. I will do a check when I visit next time for filling LPG.

If you mean in car, I do not have such one in my car. Instead it has three LED which denotes the level of LPG. So I do not know how I have to fill full tank.

As of now I am filling LPG 10 ltrs every time and reset the trip meter. When the LPG is over, automatically I will get a beap and it will get switch over to petrol. At that time I will note down the trip meter and find the KM run and calculate the milage.
I did not know that only 75% needs to be filled. So simple method would be to first make the LPG tank empty. Drive using petrol to the Filling station. Fill teh LPG to x litres. Set tripmeter to zero and Drive using only LPG till its over. The FE will be = ( no. of kms / x ) kmpl
 

sethumurugan

Honoured Member
Joined
Feb 8, 2011
Messages
3,837
Likes
1,162
Location
Chennai
Re: How to Calculate Your Car's Mileage?

I did not know that only 75% needs to be filled. So simple method would be to first make the LPG tank empty. Drive using petrol to the Filling station. Fill teh LPG to x litres. Set tripmeter to zero and Drive using only LPG till its over. The FE will be = ( no. of kms / x ) kmpl
Precicely that is waht am doing now. Thanks.
 
Top Bottom