How is PHEV mileage calculated

1126 Views 19 Replies 6 Participants Last post by PCM, 23 d ago

BlazeForth

Discussion Starter · 1 mo ago

I see this on screen. I wonder is 31.7 total mpg including the petrol and electric. Or it's just petrol only and 2.4 mile is for electric only.

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Townsmcp

· #2 · 1 mo ago

2.4 miles/kWh is electric only
31.7mpg is blended petrol and electric. The way to confirm this is put the car into EV only, make a note of the mpg, and drive for a while without using petrol. You will see the 31.7mpg will start to increase. For example, I have seen my mpg around 82mpg and then driven electric only for a few days and the mpg has gone back up to 99mpg

BlazeForth

Discussion Starter · #3 · 1 mo ago

Townsmcp said:
2.4 miles/kWh is electric only
31.7mpg is blended petrol and electric. The way to confirm this is put the car into EV only, make a note of the mpg, and drive for a while without using petrol. You will see the 31.7mpg will start to increase. For example, I have seen my mpg around 82mpg and then driven electric only for a few days and the mpg has gone back up to 99mpg

Oh, I was confused as they shown separately. Thank you for clearing that up. One more thing, so how can I see the petrol mpg only?

Townsmcp

· #4 · 1 mo ago

I don’t think you can. If you go into Information (top of the Mazda menu), you can then go into more in-depth stats/graphs but again it is blended stats for petrol/electric and separate electric.
I guess the only way would be to put the battery into 100% regen but then you would be using petrol to keep the battery topped up so mpg would suffer

BlazeForth

Discussion Starter · #5 · 1 mo ago

Townsmcp said:
I don’t think you can. If you go into Information (top of the Mazda menu), you can then go into more in-depth stats/graphs but again it is blended stats for petrol/electric and separate electric.
I guess the only way would be to put the battery into 100% regen but then you would be using petrol to keep the battery topped up so mpg would suffer

Yeah, even the driving stats shows fuel efficiency and Electric efficiency as separate, which is really confusing for a normal customer.

UKPhil

· #6 · 1 mo ago

Townsmcp said:
2.4 miles/kWh is electric only
31.7mpg is blended petrol and electric. The way to confirm this is put the car into EV only, make a note of the mpg, and drive for a while without using petrol. You will see the 31.7mpg will start to increase. For example, I have seen my mpg around 82mpg and then driven electric only for a few days and the mpg has gone back up to 99mpg

The 2.4 is also blended. If I do a run 50/50 EV ICE the end of journey stats are high for both categories. I guess it individually dives the fuel and power units into the same total miles for the journey.
What I have never figured out is how the predicted range is worked out. Today it said 270 miles with full tank and full battery. 40 miles on battery. That suggests only 230 miles on 11 gallons!

BlazeForth

Discussion Starter · #7 · 1 mo ago

UKPhil said:
The 2.4 is also blended. If I do a run 50/50 EV ICE the end of journey stats are high for both categories. I guess it individually dives the fuel and power units into the same total miles for the journey.
What I have never figured out is how the predicted range is worked out. Today it said 270 miles with full tank and full battery. 40 miles on battery. That suggests only 230 miles on 11 gallons!

That's like 20mpg 😑, which is really low.

Do you know if there is any ongoing issues showing incorrect total mileage in cluster? The reason I'm asking is because last day when I refuelled it showed 250 miles in total. We did around a 240 mile journey and it still shows 130 miles in total.
It was a mix of motorway and A road, also another thing I did is when I'm on a 60-70 mile road I turn on recharge to 80% and in sports mode. When I'm in town I turn it down to 30 something and switch to Normal mode which uses EV most of the time. Intially I was shocked, but now I'm in doubt if there is something wrong. The above snap I shared is what I got in my info for mpg.
Regen braking is set to high as well.

UKPhil

· #8 · 1 mo ago

Nothing wrong as such. I have seen that on lots of long mainly ICE runs.
I have an unproven theory. When I fill up, its close to home usually, and the trip has been mainly on EV. BUT I often use a bit of ICE to join a dual carriage way and get up to speed. A cold engine working hard will not get much MPG. The expected range is calculated on last 5 miles or so fuel usage rate and the remainder of the tank (which also keeps maybe 1 or 2 gallons back for reserve).
Therefore the expected range will be very small. Because of the cold engine.
I did get a range of 350 once and thinking back I had filled up after a gentle cross country run so the engine was warm.
I largely ignore it and use the fuel gauge which seems fairly accurate (also with a bit reserved below zero). I think the algorithm for a hybrid has a hard time predicting the future based on the past.
I never use recharge and only sport mode when overtaking or joining fast roads. Splitting out my electric and fuel use I think I'm getting around 2.5 mpKw now its warmer and about 37 mpg petrol.
For a car this size I'm happy. For comparison my CX5 auto did almost exactly that.
Because I have a good tariff my last 490 miles mainly short trips, gave me the equivalent of 65 mpg.

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Noah4x4

· #9 · 1 mo ago

On a 240 mile motorway journey last week I started with a combined range of 250 miles and still had an estimated 80 miles remaining at its conclusion. My (petrol) fuel gauge suggested a third full, with EV battery having 11 miles (having used the charge button a few times). Combined range is a complete nonsense, and EV range often understated. All I know is my combined cost is less than I was paying in my diesel, but not significantly so. Let’s hope electricity prices fall as predicted in July.

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UKPhil

· #10 · 30 d ago

Noah4x4 said:
On a 240 mile motorway journey last week I started with a combined range of 250 miles and still had an estimated 80 miles remaining at its conclusion. My (petrol) fuel gauge suggested a third full, with EV battery having 11 miles (having used the charge button a few times). Combined range is a complete nonsense, and EV range often understated. All I know is my combined cost is less than I was paying in my diesel, but not significantly so. Let’s hope electricity prices fall as predicted in July.

Thats how I look at it. Total cost is lower than my CX5, AND if I'm paying 50 grand for a car why am I worrying about a few MPG! In that case I would switch to a Mazda 2 hybrid/Yaris and get well over 80 on a run like my wife.

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BlazeForth

Discussion Starter · #11 · 30 d ago

UKPhil said:
Thats how I look at it. Total cost is lower than my CX5, AND if I'm paying 50 grand for a car why am I worrying about a few MPG! In that case I would switch to a Mazda 2 hybrid/Yaris and get well over 80 on a run like my wife.

Cool, I got yaris hybrid and 58mpg is the maximum I achieved.
but 31mpg combined with plugin battery, is not looking very good. Before trip I couldn't charge my battery to full, but I had 20 mile range. Yet 31mpg seems very low, but let's see.

UKPhil

· #12 · 30 d ago

BlazeForth said:
Cool, I got yaris hybrid and 58mpg is the maximum I achieved.
but 31mpg combined with plugin battery, is not looking very good. Before trip I couldn't charge my battery to full, but I had 20 mile range. Yet 31mpg seems very low, but let's see.

We did 90 miles today around the hills of Derbyshire probably not above 50 all day. The fuel gauge didn't move and the MPG meter showed 79 mpg

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BlazeForth

Discussion Starter · #13 · 28 d ago

UKPhil said:
We did 90 miles today around the hills of Derbyshire probably not above 50 all day. The fuel gauge didn't move and the MPG meter showed 79 mpg

How are you checking it? I drove around 20 miles in normal mode today and this is what drive efficiency shows which is only the EV average. So I believe ev efficiency and fuel efficiency are calculated separately.

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UKPhil

· #14 · 28 d ago

BlazeForth said:
How are you checking it? I drove around 20 miles in normal mode today and this is what drive efficiency shows which is only the EV average. So I believe ev efficiency and fuel efficiency are calculated separately.
View attachment 332

My bad: I was talking about the Mazda 2 Hybrid.
In the CX60. I know my total costs between fil up and can convert to equivalent galls and hence MPG. I can also using the history diagrams slice out the EV miles and then work our the Petrol MPG. Not Perfect but good enough.
Its for my curiosity more than anything else: It is what it is. I can't do anything about it.

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BlazeForth

Discussion Starter · #15 · 28 d ago

UKPhil said:
My bad: I was talking about the Mazda 2 Hybrid.
In the CX60. I know my total costs between fil up and can convert to equivalent galls and hence MPG. I can also using the history diagrams slice out the EV miles and then work our the Petrol MPG. Not Perfect but good enough.
Its for my curiosity more than anything else: It is what it is. I can't do anything about it.

No worries, I believe I'm also getting really good mpg's out of my cx60.

PCM

· #16 · 23 d ago

UKPhil said:
My bad: I was talking about the Mazda 2 Hybrid.
In the CX60. I know my total costs between fil up and can convert to equivalent galls and hence MPG. I can also using the history diagrams slice out the EV miles and then work our the Petrol MPG. Not Perfect but good enough.
Its for my curiosity more than anything else: It is what it is. I can't do anything about it.

Out of interest, what sort of petrol mpg are you achieving?

BlazeForth

Discussion Starter · #17 · 23 d ago

PCM said:
Out of interest, what sort of petrol mpg are you achieving?

I drove most of the part in sport mode, and mainly motorways. I get around 33mpg max.

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PCM

· #18 · 23 d ago

BlazeForth said:
I drove most of the part in sport mode, and mainly motorways. I get around 33mpg max.

Thanks for the quick response!

EdGe

· #19 · 23 d ago

As a driver you just take the miles driven since last fuel stop & divide by mils driven. This is your gas mileage for this tank. It doesn't take into consideration the contribution from Batt/Elec.motor. You just assume that it is contributing to the overall mileage. Engineers will calculate battery/motor contribution, cost of electricity, cost of gasoline, do some math and then give you a number. But all you really care about is that your SUV is giving you 40mpg or better because of the electric assist.

PCM

· #20 · 23 d ago

EdGe said:
As a driver you just take the miles driven since last fuel stop & divide by mils driven. This is your gas mileage for this tank. It doesn't take into consideration the contribution from Batt/Elec.motor. You just assume that it is contributing to the overall mileage. Engineers will calculate battery/motor contribution, cost of electricity, cost of gasoline, do some math and then give you a number. But all you really care about is that your SUV is giving you 40mpg or better because of the electric assist.

Thanks.

It's important to me to know the combined 'real world' mpg I'll be getting for my car. So, when I get it, I'll keep a detailed spreadsheet of the miles driven and the cost of petrol plus electricity. This will enable me (after, say 3 or 4 months) to work out the equivalent mpg for petrol/electric compared to an average gallon of petrol.

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