Modern Vespa

Should calculating km/L / mpg include stationary at the lights?

The resultant numbers are quite different (typically about 10%). What feels more natural to you?

I see arguments for and against ...

Excluding stationary seems to give numbers similar to the bike's dashboard. But it's arguably not honest.

Including is more useful for estimating what the trip cost in fuel / how often you'll need to stop.

AND same question for average speed?

PS. This is of course a question of what should my app show. Showing both clutters ui and confuses users.

How many litres per hour typically at idle?

I can't speak for scooters, as I've never idled in place for a long time on one.
However, for a 4-cylinder engine, idling for 8 hours, I calculated it consumed about 2 gallons of fuel.

Idle is 0.6 litres / hour at 1700 rpm

And *very roughly when steady* at 100 kph (gps) it's a little over 5 litres / hour and at 120 around 6 ish. Peak I've reached is 7.2 during *acceleration* to 121 kph / 9100 rpm. These numbers are only presented as a very approx comparison to idle - in reality these numbers are very wobbly


Note:
Litres / hour is reported by the ECU continuously and is very spikey
/ sensitive to the slightest throttle movement when you are trying to keep a steady speed.
This is not a number calculated by me.

There is identical fuel economy at 120 and 100?
Bernoulli says no way.

?

5 does not equal 6

No.
But 100/5 does equal 120/6.
20km/l for both speeds.

Sure, but this is where the word *roughly* comes into it.

Here's a some real data, observe the spikiness due to throttle adjustments to try and keep a constant speed

For me, it would feel odd if idling consumption was omitted from the figures.

My own 520 lbs whale-of-a-bike consumes quite a lot in stop-start city traffic compared to slow speed cruising...and, unfortunately, it does not have any idle stop-start cleverness build-in.

I agree but then I don't get the same numbers as the dashboard nor what piaggio claims in the specs. Users would claim my software is buggy.

I would agree with this ^^^^^^^^
Fuel consumption should reflect the journey end to end, hence stop start feature on the little Vespas. Over 15 yrs ago I visited a big haulage company. They had trackers in the cabs of their drivers and they were disciplining drivers who idled in traffic , rather than stopping the engine.

I thought it was Draconian then, hopefully stop start will have lowered the BP of the fleet managers.

In Europe (especially in Germany) it is more common to indicate the liters used per 100km (i.e. xyL/100km).

Example:
Distance: 743 km
Consumption for this distance: 53 liters
53 l/743 km = 0.0713 x 100 = 7.13 l/100 km

Your average consumption is therefore 7.13 liters per 100 kilometers.

Regardless of whether you calculate the range from one liter/gallon or how many liters/gallons are needed for 100 km/mile: Of course, this always includes the waiting phases at traffic lights, traffic jams, etc.

If you ask this for your app: if it is possible for you, please also enter the European calculation method as an option.

so no one wants numbers that match the dashboard?

Can you chart l/h vs speed?

Blue line on top graph vs red line on bottom graph

According to my observations, on-board computers in all vehicles show overly optimistic (embellished) consumption values, regardless of whether we are talking about city traffic, overland or full speed on the highway. I do not assume that this is only due to the non-calculation of consumption during idle times.

I would also work with selection options here:
1. mirrored value according to display
2. more realistic value
(and this also as L per 100km)

Yes please.

🤦‍♂️

Scroll back and look

Can you chart l/h vs speed, not l/h and speed vs time.

With a little highlighting of stable speed and also minor smoothing