[condor]

Originally Posted by dailydriver

The perceived benefit of filling up early in the morning because of the supposedly denser fuel is an incentive too..

I wont say it is perception, but denser fuel is more in the vechicle's tank than at the fuel station.

While the colder temps May add to the perception of fuel at the pump being denser in the mornings, it is the tanks in our cars that are exposed to the outside temperatures. Due to this exposure, the fuel in the tank would expand as the temperature in the day increases. More so when travelling on the highway during summer months.

So I do try to fill in the morning most times.

[a4anurag]

Originally Posted by vvivek85

Need your valuable suggestion, usually, I will follow the tank full to tank full method of refuelling. However, now the usage of the car is very minimal, in this scenario what method should I follow? If I follow the same method, will the fuel be evaporated due to minimal usage? Appreciate your expert opinion.

What is the current usage?

If the car is not parked under the direct sun then I see no issues but even then overall evaporation loss shouldn't be alarming.

[condor]

A note regarding the top-up method of refuel: Even though many say it is not safe, my take is that, the top-up lasts may be a couple of minutes. Very soon after one moves away from the bunk, the fuel in the neck of the tank will settle down into the tank. Most times, I drive a fair bit after the refuel, so the fuel anyway goes down below the full.

Originally Posted by vvivek85

... usually I will follow tank full to tank full method of refueling. .

Lesser fuel in the tank, more the evaporation. So try keep the fuel full.

[sreenivass]

I generally fill it up to auto cut off. Recently started filling to the brim before going to home town. This way I can avoid refilling enroute, filled to the brim would last until the end of round trip. I make it a point to note where it cuts off and how much is filled beyond auto cutoff.

[Jeroen]

Originally Posted by condor

Lesser fuel in the tank, more the evaporation. So try keep the fuel full.

Not really, these days almost all fuel system are closed, so no evaporation to the outside anymore. Bit of myth still, doing the rounds on many car forums.

Jeroen

[condor]

Originally Posted by Jeroen

Not really, these days almost all fuel system are closed, so no evaporation to the outside anymore.

To say that the vapor escapes on some occasions (like warm/hot day) would be to nit-pick. I myself dont bother much about that. My refuels are more about convenience, like when I am close to reserve And I am near one of my regular bunks.

[Indian2003]

My fuel tank is 80 liters. I alway fill up until the auto cut-off kicks in. I fill up at any time of the day. Some say the fuel is denser early mornings and late nights but the tanks at the station are all underground and keeps a stable temperature.

My car weighs 2700 kilos and plus/minus 100 kilos is hardly noticable to fuel consumption.

I fill up at 1/2 to 3/4 tank to avoid condensation in the fuel tank. I dont use any additives.I normally fill about 60 liter to full.

[anivy]

A circular from the Legal Metrology Division dated 6/March/2023 asks users not to fill the fuel tanks to the brim and instead limit it to the capacity indicated by the manufacturer.
Reasons per the circular below:

i. To prevent Volatile Organic Compound from being leaked in case of volume expansion, as underground tanks at petrol pumps have lower temperature compared to atmosphere.

ii. Gasoline needs space for vapor creation, and if not provided then the output of the engine performance will suffer and unburnt fuel will add to more hydrocarbon pollution.

iii. If a vehicle is filled with full capacity to the brim then the fuel if parked at a slant may leak and may bring about fire being hazardous and explosive.

Source

[masterChief007]

Originally Posted by anivy

users not to fill the fuel tanks to the brim and instead limit it to the capacity indicated by the manufacturer.
Reasons per the circular below:

Isn't the FI/Carb is there for the reason number 2? By the way I do it tank full always (auto cut and round off). And when reaching hill station I top up just at the foot hills (have seen sometimes petrol stations run out of fuel in hills)