Kia Sonet: Trying to understand how my car calculates mileage

Is it simple average of Accumulated Average & Last Drive Average?

BHPian tchkreddy recently shared this with other enthusiasts.

While I understand from various forums that DTE is not very accurate due to lot of parameters impacting it, I'm curious as to how it gets calculated in first place. It is basically Fuel * Average Mileage.

I was trying to figure out which Average Mileage it picks from in my Kia Sonet HTK+. Since both 'Remaining Fuel' and 'Average Mileage' are both reported by car only, I wanted to freeze one to discover another, so used full tank method.

Here are the numbers before refuelling.

• DTE: 49
• Accumulated Avg: 9.1 (Trip meter with manual reset)
• Last Drive Info Avg: 18.2 (Trip meter reset on every ignition)
• Fuel Economy Avg: 9.8 (Trip meter reset on refuelling)
• I did a full tank with 40.74 L

Now DTE is 604. Means a jump of 555 km.

555/40.74 = 13.6 kmpl

Can anyone help me with how it derived 13.6?

Is it simple average of Accumulated Avg & Last Drive Avg? (18.2 + 9.1)/2 ?

Here's what BHPian Rehaan had to say on the matter:

The "algorithm" used for calculating DTE is bound to be more complex than a linear equation.

Tweaks to combat human psychology, as well as the manufacturer's liability will be (in terms of stranded drivers!) will be worked in.

Each manufacturer would have a different formula too -- which is why owners feel that certain cars have a much more reliable DTE than others.

In other words, its incredibly unlikely that you'll be able to reverse-engineer the formula, despite your best testing efforts.

Read BHPian comments for more insights and information.