Fuel consumption accuracy

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alan sh
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Post by alan sh » Sat Apr 30, 2022 3:47 pm

Filled up today. 360 miles (mixture of motorway and town driving) and my fuel app (Fuely) told me I got 44.9 mpg. The internal gauge told me 44.7 mpg - so pretty accurate.

Overall the car shows 42.1 and Fuely shows 42.2.

It's more accurate than my BMW was.

Alan
Alan

I own a 2022 Ultimate Hybrid with Tech Pack - in Red (best colour).
Also have two motorcycles. Honda CB1300 and Honda CBF1000 (also red, of course).

old man
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Post by old man » Sat Apr 30, 2022 4:41 pm

That's heartening to know, I haven't filled mine since I took delivery.
Tucson N Line S 2WD Hybrid

roadster
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Post by roadster » Sun May 01, 2022 8:33 am

The plug in is showing an overall figure of 51 to 52 mpg at the moment but without taking account of the electricity consumed. To be useful there would have to be a record of miles per KW.Hour or to be scientific Miles per Joule assuming we are still not comfortable measuring distance in Kilometres. For now I content myself with calculations that suggest around 30 miles per 14 Kw.H which is costing about the same as 2 litres of petrol so a financial equivalent of very roughly 70 mpg. Not much of a saving but I suppose there are other benefits in the wider sense. If used exclusively in hybrid mode individual journeys show about 41 mpg because of the plug-in's extra weight and complexity.
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madowl
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Post by madowl » Sun May 01, 2022 1:58 pm

roadster wrote:
Sun May 01, 2022 8:33 am
The plug in is showing an overall figure of 51 to 52 mpg at the moment but without taking account of the electricity consumed. To be useful there would have to be a record of miles per KW.Hour or to be scientific Miles per Joule assuming we are still not comfortable measuring distance in Kilometres. For now I content myself with calculations that suggest around 30 miles per 14 Kw.H which is costing about the same as 2 litres of petrol so a financial equivalent of very roughly 70 mpg. Not much of a saving but I suppose there are other benefits in the wider sense. If used exclusively in hybrid mode individual journeys show about 41 mpg because of the plug-in's extra weight and complexity.
Are your figures correct? Say you make journeys of 100 miles per day, 30 of that being pure electric so 70 miles in hybrid mode. The car mpg shows 50mpg but in effect the ICE has only been running for 70 miles which equals 35mpg.
I know the PHEV, in hybrid mode, is less efficient than the full hybrid due to the extra weight etc but should return 45mpg which combined with the ev mode would give you around 65mpg over 100 miles.

roadster
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Post by roadster » Mon May 02, 2022 8:37 am

madowl wrote:
Sun May 01, 2022 1:58 pm
roadster wrote:
Sun May 01, 2022 8:33 am
The plug in is showing an overall figure of 51 to 52 mpg at the moment but without taking account of the electricity consumed. To be useful there would have to be a record of miles per KW.Hour or to be scientific Miles per Joule assuming we are still not comfortable measuring distance in Kilometres. For now I content myself with calculations that suggest around 30 miles per 14 Kw.H which is costing about the same as 2 litres of petrol so a financial equivalent of very roughly 70 mpg. Not much of a saving but I suppose there are other benefits in the wider sense. If used exclusively in hybrid mode individual journeys show about 41 mpg because of the plug-in's extra weight and complexity.
Are your figures correct? Say you make journeys of 100 miles per day, 30 of that being pure electric so 70 miles in hybrid mode. The car mpg shows 50mpg but in effect the ICE has only been running for 70 miles which equals 35mpg.
I know the PHEV, in hybrid mode, is less efficient than the full hybrid due to the extra weight etc but should return 45mpg which combined with the ev mode would give you around 65mpg over 100 miles.
If only it were that simple! The figure that shows up on the instrument panel is just a lifetime average ( or since reset) and how much electrical assistance was used over that lifetime is not quantifiable. So far it seems that if hybrid mode is selected the available traction battery reserve does not change significantly on the journey, but in truth I haven't done a long enough journey in that mode to give a definitive result for mpg. It is possible to use electric mode to bias against starting the engine but it will still kick in if the accelerator pedal is pressed too enthusiastically. I try to anticipate the lower speed parts of a journey and switch to electric for those but I also try to use up remaining charge if I am nearing journeys end.
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madowl
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Joined: Fri Feb 11, 2022 5:45 pm

Post by madowl » Tue May 03, 2022 7:37 pm

roadster wrote:
Mon May 02, 2022 8:37 am
madowl wrote:
Sun May 01, 2022 1:58 pm
roadster wrote:
Sun May 01, 2022 8:33 am
The plug in is showing an overall figure of 51 to 52 mpg at the moment but without taking account of the electricity consumed. To be useful there would have to be a record of miles per KW.Hour or to be scientific Miles per Joule assuming we are still not comfortable measuring distance in Kilometres. For now I content myself with calculations that suggest around 30 miles per 14 Kw.H which is costing about the same as 2 litres of petrol so a financial equivalent of very roughly 70 mpg. Not much of a saving but I suppose there are other benefits in the wider sense. If used exclusively in hybrid mode individual journeys show about 41 mpg because of the plug-in's extra weight and complexity.
Are your figures correct? Say you make journeys of 100 miles per day, 30 of that being pure electric so 70 miles in hybrid mode. The car mpg shows 50mpg but in effect the ICE has only been running for 70 miles which equals 35mpg.
I know the PHEV, in hybrid mode, is less efficient than the full hybrid due to the extra weight etc but should return 45mpg which combined with the ev mode would give you around 65mpg over 100 miles.
If only it were that simple! The figure that shows up on the instrument panel is just a lifetime average ( or since reset) and how much electrical assistance was used over that lifetime is not quantifiable. So far it seems that if hybrid mode is selected the available traction battery reserve does not change significantly on the journey, but in truth I haven't done a long enough journey in that mode to give a definitive result for mpg. It is possible to use electric mode to bias against starting the engine but it will still kick in if the accelerator pedal is pressed too enthusiastically. I try to anticipate the lower speed parts of a journey and switch to electric for those but I also try to use up remaining charge if I am nearing journeys end.
No, not simple but still possible to get a better calculation on longer journeys.

roadster
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Location: South Coast

Post by roadster » Sun May 08, 2022 3:48 pm

Here is an interesting test of PHEV consumption. Today I took a journey of 45 miles each way. Very close to identical condition and the same route in both directions. It included about 30 miles of motorway each way but because of extra speed limits and traffic conditions most of the motorway miles were at just over 60 mph with about 6 miles at 70+. For the outward journey I used hybrid mode so the engine fired up immediately and very little if any battery reserve was used. Result for the hybrid only leg - 44 mpg. On the return run I used automatic mode with the engine not being used until motorway speeds and then not very much. Result for automatic leg - 70 mpg! What is more only 50% of the battery capacity was consumed.

An amazing result even for ECO mode. I also used cruise control for most of the journey and only used air-conditioning for a short time. Were the end of journey figures accurate? I have no idea. These are summer time figures in almost perfect conditions and using E5 Shell.
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alan sh
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Post by alan sh » Sun May 08, 2022 5:47 pm

I just did a 260 mile journey. Mostly motorway (M62, M60, M62, M6, M42) sitting at 70 mph but with about 60 miles of roadworks (M6) sitting at 60. No real holdups and active cruise control for most of it.

Overall consumption was 47 mpg. Which is better than my old BMW X3 would have done. On the way down to Coventry, I had air con turned off - on the way back, it was turned on. No real difference in mpg that I could determine.
Alan

I own a 2022 Ultimate Hybrid with Tech Pack - in Red (best colour).
Also have two motorcycles. Honda CB1300 and Honda CBF1000 (also red, of course).

madowl
Posts: 88
Joined: Fri Feb 11, 2022 5:45 pm

Post by madowl » Mon May 09, 2022 5:04 pm

roadster wrote:
Sun May 08, 2022 3:48 pm
Here is an interesting test of PHEV consumption. Today I took a journey of 45 miles each way. Very close to identical condition and the same route in both directions. It included about 30 miles of motorway each way but because of extra speed limits and traffic conditions most of the motorway miles were at just over 60 mph with about 6 miles at 70+. For the outward journey I used hybrid mode so the engine fired up immediately and very little if any battery reserve was used. Result for the hybrid only leg - 44 mpg. On the return run I used automatic mode with the engine not being used until motorway speeds and then not very much. Result for automatic leg - 70 mpg! What is more only 50% of the battery capacity was consumed.

An amazing result even for ECO mode. I also used cruise control for most of the journey and only used air-conditioning for a short time. Were the end of journey figures accurate? I have no idea. These are summer time figures in almost perfect conditions and using E5 Shell.
It is difficult to work anything out accurately. One thing I find strange though is why on the return leg you didn't use the battery to exhaustion as this is marginally cheaper and less emmisions?

roadster
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Joined: Fri Feb 04, 2022 3:01 pm
Location: South Coast

Post by roadster » Tue May 10, 2022 9:10 am

madowl wrote:
Mon May 09, 2022 5:04 pm
It is difficult to work anything out accurately. One thing I find strange though is why on the return leg you didn't use the battery to exhaustion as this is marginally cheaper and less emmisions?
I wanted a consistent experiment. In effect I travelled 15 miles on electric power and 30 on petrol so taking the car's reported consumption figure of 70mpg I used 45/70 gallons but it actually covered 30 miles so the real petrol consumption was 30 divided by 45/70 = 30 X 70 / 45 which is approximately 46.7 mpg which can be directly compared to the hybrid only figure of 44 mpg. The conclusion being that the automatic mode is more efficient than hybrid only mode by a small margin. However this is only true if there is reserve left in the traction battery because at a battery level of 12 to 15 % automatic mode would in effect revert to hybrid.

In these particular conditions the most efficient way of making this 90 mile round trip would have been to start with a full battery and leaving the car in automatic mode which would have resulted in the traction battery being effectively depleted by the end of the trip. Suggesting that the optimal distance between charging would be about 90 miles when on longer journeys.
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