Anyone know what the mpg display is showing?

[Phevourite]

Much of Harvey's driving is done in pure EV mode. I have brought him to London twice now been intrigued by the mpg reading. I assumed before that what it gave was the consumption for the whole trip. I now realise that cannot be though as that would put the fuel consumption at around the low 20 something mpg. Also; based on previous measurements it suggests that the better I drive then the worse the consumption which does not make sense. Instead I now guess the consumption is the the non-EV part of the journey. Here are the numbers...

o The whole drive was 68 miles
o 25 miles of country roads, 8 miles of city driving and the rest motorway
o Kept the speed very constant and mostly below about 65 mph
o The car managed 60% on EV (so it said)
o That works out at 41 EV miles and 27 non-EV miles
o It claimed 57.8 mpg
o And 4.6kWh for electric consumption

If the 57.8 is for the non-EV parts of the journey then Harvey did manage 144.5 mpg for the whole trip (and ignoring the electricity used). I can believe this and it fits with the claimed official fuel consumption number. I am not so convinced that the batteries managed 40 miles though. Seems rather high. I alternated between "normal" and "save" modes. Using "normal" through the villages and the city. Watching the info display I could see that at times Harvey ran from batteries even in save mode and at other times had the engine driving the car and claiming to be re-charging at the same time. This suggests there is some charge/re-charge stuff going on there which could explain the high EV figure.

Anyone know what the mpg display is reading exactly? Anyone else seeing similar numbers?

 

[Regulo]

In "Save" mode, the car will try to keep the set charge in the battery. It does this by recharging, then running on electric, re-charging, running on electric and so on. If you watch the "miles remaining" on electric whilst in Save mode, you'll see it going up and down by a few miles. That's why you see 40 miles EV - it's including the miles run on EV while in save mode. Figures sound about right to me.

 

[Neverfuel]

Much of Harvey's driving is done in pure EV mode. I have brought him to London twice now been intrigued by the mpg reading. I assumed before that what it gave was the consumption for the whole trip. I now realise that cannot be though as that would put the fuel consumption at around the low 20 something mpg. Also; based on previous measurements it suggests that the better I drive then the worse the consumption which does not make sense. Instead I now guess the consumption is the the non-EV part of the journey. Here are the numbers...

o The whole drive was 68 miles
o 25 miles of country roads, 8 miles of city driving and the rest motorway
o Kept the speed very constant and mostly below about 65 mph
o The car managed 60% on EV (so it said)
o That works out at 41 EV miles and 27 non-EV miles
o It claimed 57.8 mpg
o And 4.6kWh for electric consumption

If the 57.8 is for the non-EV parts of the journey then Harvey did manage 144.5 mpg for the whole trip (and ignoring the electricity used). I can believe this and it fits with the claimed official fuel consumption number. I am not so convinced that the batteries managed 40 miles though. Seems rather high. I alternated between "normal" and "save" modes. Using "normal" through the villages and the city. Watching the info display I could see that at times Harvey ran from batteries even in save mode and at other times had the engine driving the car and claiming to be re-charging at the same time. This suggests there is some charge/re-charge stuff going on there which could explain the high EV figure.

Anyone know what the mpg display is reading exactly? Anyone else seeing similar numbers?

The % EV driving figure is not that accurate if you are trying to rely on it for working out mpg. This is because the % will be affected by just the engine starting, eg to heat the car! fast acceleration! heavy load etc. It doesn't go on the mileage. The MPG figure seems to be quite accurate though, both on auto (which resets itself after 4 hours of the car being turned off), and in manual (which needs you to reset it). I check the manual figure against the miles completed and the fuel used (brim to brim fill ups), monthly and it always spot on - I have never reset the manual mpg figure so it always shows the lifetime mileage of the car.

The mpg figure is showing you the combined EV driving and petrol use for a particular journey, which is why it starts out at --.- (presumably on yours it will now show a 3 figure mpg display, but we don't have that luxury). The mpg figure will then start to drop, the more miles you do. If you use save mode whilst the engine is running and then turn it off once you have built up some SOC, the car will revert to running in EV mode and your mpg will increase accordingly.

I have tried to replicate my mpg figures by using the % EV driving figure and the miles driven from the odometer to see if they match, but they never come close.

 

[DazzyB]

I'm certain that the mpg figure is for the whole journey and combines EV and ICE.

I do the same 60 mile journey every day to work. If I start with full charge and drive "sensibly" the mpg figure by the end can be around 73mpg. If I start out with no charge and do the whole trip on ICE the mpg is 30-35MPG.

There's no way your car could be doing 57.8mpg on the ICE only part of that journey (unless it's all downhill). Sorry.

 

[Phevourite]

I'm certain that the mpg figure is for the whole journey and combines EV and ICE.

I do the same 60 mile journey every day to work. If I start with full charge and drive "sensibly" the mpg figure by the end can be around 73mpg. If I start out with no charge and do the whole trip on ICE the mpg is 30-35MPG.

There's no way your car could be doing 57.8mpg on the ICE only part of that journey (unless it's all downhill). Sorry.

I have to admit that nearly 60 mpg does seem ridiculously high for the petrol-only parts of the journey. Then again 23 mpg seems ridiculously low. Especially given how carefully and gently I was driving. This 23 figure is what the mileage would be for the ICE section if I calculate petrol sections based on an overall 57.8 mpg. It could be that the percentage EV value is very misleading. If it were 40% instead of 60% then the consumption would be about 34 mpg which is not that great either.

 

[Phevourite]

In "Save" mode, the car will try to keep the set charge in the battery. It does this by recharging, then running on electric, re-charging, running on electric and so on. If you watch the "miles remaining" on electric whilst in Save mode, you'll see it going up and down by a few miles. That's why you see 40 miles EV - it's including the miles run on EV while in save mode. Figures sound about right to me.

That cycling certainly fits with what I saw. There were a lot of gentle up/down slopes through the villages and it seemed to run the engine up hill and use battery power down even though the slopes were sometimes quite gentle. Good to hear that you think the numbers sound right Regulo.

 

[Phevourite]

I have tried to replicate my mpg figures by using the % EV driving figure and the miles driven from the odometer to see if they match, but they never come close.

Maybe this is not a useful method then Neverfuel. It is a pity that it doesn't work because it is fascinating to try and maximise the mileage.

 

[anko]

EV% is not just miles driven on grid electricity, but includes miles driven on energy generated while driving. So, even when you take off with an empty battery, you could still expect 20 - 40% EV driving, depending on circumstances. When you try to calculate fuel consumption back to the periods of non-EV driving, the resulting number will include the gas used to generate electrical power for the periods of EV driving. You should expect relatively high numbers there. Don't know about MPG, but while driving 100 km/h in parallel mode, instantaneous fuel consumption can easily be 11 l/100 km or more.

Botom line: it does not make a whole lot of sense to calculate this number and evaluate it outside of it's context

 

[Neverfuel]

Think of it like this:

Your journey was 68 miles - forget how it breaks down into different types of road etc.

Let's say you get 20 miles of grid provided EV driving - that's infinite mpg according to the car.

So you have driven 48 miles on a mixture of petrol and car generated electricity. Approx 30 % of the 68 miles were pure EV. To know your actual mpg, you need to know how much fuel was used.

If we take the car mpg as being accurate, it recorded 57.8 mpg (which was only consumed during 48 miles of the trip). If you divide 57.8 by the number of litres in a gallon (4.55) you get 12.7 miles per litre. If you then divide your total mileage (68) by miles per litre (12.7) you will get the number of litres used - 5.35.

Bearing in mind that you used 5.35 litres over the course of 48 miles, we can now work out the petrol consumption of the engine during that part of the trip. 48 / 5.35 = 8.97 miles per litre x 4.55 (litres in a gallon) = 40.8 mpg for the part of your trip without grid provided EV.

To work out what the actual mpg of ICE (without car generated EV) is now a different matter and you can probably see that the EV dial indicating 60% is way out of the ball park. That's why I don't use it in my calculations, as it can't make sense when you do the calcs.

The figures you use will always be based on assumption apart from knowing accurate odometer readings; filling brim to brim and recording the amount of fuel used; and, when you really get bored, working in the electricity usage to work out your MPGE!

Enjoy your car, hope this helps.

Everyday is a school day! :lol:

 

[Regulo]

Everyday is a school day! :lol:

Please, Sir, I want to go home!

 

[anko]

Think of it like this:

Your journey was 68 miles - forget how it breaks down into different types of road etc.

Let's say you get 20 miles of grid provided EV driving - that's infinite mpg according to the car.

So you have driven 48 miles on a mixture of petrol and car generated electricity. Approx 30 % of the 68 miles were pure EV. To know your actual mpg, you need to know how much fuel was used.

If we take the car mpg as being accurate, it recorded 57.8 mpg (which was only consumed during 48 miles of the trip). If you divide 57.8 by the number of litres in a gallon (4.55) you get 12.7 miles per litre. If you then divide your total mileage (68) by miles per litre (12.7) you will get the number of litres used - 5.35.

Bearing in mind that you used 5.35 litres over the course of 48 miles, we can now work out the petrol consumption of the engine during that part of the trip. 48 / 5.35 = 8.97 miles per litre x 4.55 (litres in a gallon) = 40.8 mpg for the part of your trip without grid provided EV.

Uhhh ..... Non-GRID MPG = (Total trip MPG) / (total trip miles) * (non-GRID miles): 57.8 / 68 * 48 = 40.8

Next time, wouldn't that be a lot easier?

To work out what the actual mpg of ICE (without car generated EV) is now a different matter and you can probably see that the EV dial indicating 60% is way out of the ball park. That's why I don't use it in my calculations, as it can't make sense when you do the calcs.

Not that far out of the ball park. Look at it this way: 60% of 68 miles would be 40.8 (a different 40.8 this time :mrgreen: ) EV miles. 20 of those are assumed to be GRID miles, so 20.8 should be non GRID EV miles. These 20.8 miles are 41.7% of the total amount of non GRID miles (48). That should not be unachievable, if you take it easy ....

Add it all up and it totally makes sense:

40.8 MPG over 48 miles, of which 41.7% is EV. That means 23.8 MPG when you only look at the pterol miles. According to http://mpg.webix.co.uk that means 11.9 l/100km. Didn't I say something about 11 km/100l or more :mrgreen: Totally realistic.

Now you have 40.8 MPG over non-GRID miles. That is a nice figure. Does it really matter wether it is 25% EV and 30.6 MPG over petrol miles and not for example 50% EV and 20.4% MPG over petrol miles? Not for our wallets. But it would matter in the sense that the car probable wouldn't able to do 25% over 30.6, because during the time the engine was running it would be running at a lower load and thus less efficient.

 

[Neverfuel]

Think of it like this:

Your journey was 68 miles - forget how it breaks down into different types of road etc.

Let's say you get 20 miles of grid provided EV driving - that's infinite mpg according to the car.

So you have driven 48 miles on a mixture of petrol and car generated electricity. Approx 30 % of the 68 miles were pure EV. To know your actual mpg, you need to know how much fuel was used.

If we take the car mpg as being accurate, it recorded 57.8 mpg (which was only consumed during 48 miles of the trip). If you divide 57.8 by the number of litres in a gallon (4.55) you get 12.7 miles per litre. If you then divide your total mileage (68) by miles per litre (12.7) you will get the number of litres used - 5.35.

Bearing in mind that you used 5.35 litres over the course of 48 miles, we can now work out the petrol consumption of the engine during that part of the trip. 48 / 5.35 = 8.97 miles per litre x 4.55 (litres in a gallon) = 40.8 mpg for the part of your trip without grid provided EV.

Uhhh ..... Non-GRID MPG = (Total trip MPG) / (total trip miles) * (non-GRID miles): 57.8 / 68 * 48 = 40.8

Next time, wouldn't that be a lot easier?

I wanted to introduce the litres bit for the OP to introduce the concept of checking fuel level against mileage.

To work out what the actual mpg of ICE (without car generated EV) is now a different matter and you can probably see that the EV dial indicating 60% is way out of the ball park. That's why I don't use it in my calculations, as it can't make sense when you do the calcs.

Not that far out of the ball park. Look at it this way: 60% of 68 miles would be 40.8 (a different 40.8 this time :mrgreen: ) EV miles. 20 of those are assumed to be GRID miles, so 20.8 should be non GRID EV miles. These 20.8 miles are 41.7% of the total amount of non GRID miles (48). That should not be unachievable, if you take it easy ....

Add it all up and it totally makes sense:

40.8 MPG over 48 miles, of which 41.7% is EV. That means 23.8 MPG when you only look at the pterol miles. According to http://mpg.webix.co.uk that means 11.9 l/100km. Didn't I say something about 11 km/100l or more :mrgreen: Totally realistic.

Now you have 40.8 MPG over non-GRID miles. That is a nice figure. Does it really matter wether it is 25% EV and 30.6 MPG over petrol miles and not for example 50% EV and 20.4% MPG over petrol miles? Not for our wallets. But it would matter in the sense that the car probable wouldn't able to do 25% over 30.6, because during the time the engine was running it would be running at a lower load and thus less efficient.

I get what you are saying (actually just a minor correction 20.8 / 48 = 43.33% - not that it makes much difference overall). My point is more about the fact that the car could generate 43% of its own energy over 48 miles, way out with the Mitsubishi quoted figures and just doesn't seem to ring true from a common sense perspective, IMHO.

 

[Neverfuel]

The other thing that concerns me about relying on the EV % figure! is that you could sit on your drive and start the car! but it starts up the heater. The engine will only run at 1100 rpm if you don't move, yet the EV % figure moves down. I don't think there is a direct 1:1 relationship between distance an % EV, I think there may also be a time element.

 

[anko]

I get what you are saying (actually just a minor correction 20.8 / 48 = 43.33% - not that it makes much difference overall). My point is more about the fact that the car could generate 43% of its own energy over 48 miles, way out with the Mitsubishi quoted figures and just doesn't seem to ring true from a common sense perspective, IMHO.

Forgot to type in the ".8" of the "20.8" when doing the math (or having the math done for me) :|

But what quote are you referring to? I was not aware of Mitsu quoting a number for max %EV .....?

In the mean time, please look at the next picture. This is for a 90 km drive, just a little shy of the 68 miles. Don't you think this could be reflecting 60% EV over the full trip and / or 40% of the trip beyond GRID range? Perhaps even in terms of distance travelled?

Like I said, I see (at 100 km/h steady pace) > 11 l/100 km in parallel mode, where overall consumption turns out to be little over 7 l/100 km. For this you need almost 40% EV driving.

The other thing that concerns me about relying on the EV % figure! is that you could sit on your drive and start the car! but it starts up the heater. The engine will only run at 1100 rpm if you don't move, yet the EV % figure moves down. I don't think there is a direct 1:1 relationship between distance an % EV, I think there may also be a time element.

Never checked whether it does. I take your word for it . But even if %EV is affected by this, it doesn't matter a whole lot. Like I said, does it matter whether it is 25% EV over 30.6 MPG or 50% EV over 20.4% MPG? As long as the end result is the same. One thing is clear to me: it does not make sense to compare instantaneous fuel consumption of a hybrid car with that of a normal car.

 

[Neverfuel]

The other thing that concerns me about relying on the EV % figure! is that you could sit on your drive and start the car! but it starts up the heater. The engine will only run at 1100 rpm if you don't move, yet the EV % figure moves down. I don't think there is a direct 1:1 relationship between distance an % EV, I think there may also be a time element.

Never checked whether it does. I take your word for it . But even if %EV is affected by this, it doesn't matter a whole lot. Like I said, does it matter whether it is 25% EV over 30.6 MPG or 50% EV over 20.4% MPG? As long as the end result is the same. One thing is clear to me: it does not make sense to compare instantaneous fuel consumption of a hybrid car with that of a normal car.

Totally with you on that one Anko, which Is why I chose to use cost per mile, as I know how much the car costs me in petrol and electricity, and I can see the monthly trends. Mpg is only really calculable when you brim the tank and compare it to your last reading, we really cannot be fully aware of when the ICE kicks in and be expected to remember the exact conditions of why and when by the time we are analysing data.

I am currently keeping a log for the entire month of every journey, how much on EV before the ICE kicks in, outside air temp, starting EV calc, ending EV calc, mileage completed, cost per charge and MMCS charge bars used. That is difficult enough to remember to get the data when you get in or exit the car. I also have starting lifetime MPG from the beginning of the month and will take readings for the ending MPG + litres used brim to brim in the month and obviously mileage.

I will keep you posted on that one, but so far it seems that, even though I do not change my driving style, and most of my journeys have been local this month (under the EV capable range), there are many spurious readings, even with similar temperatures and exactly the same journey / traffic.

My thought is to try and graph the degradation in charge vs range during the winter months and the lower SOC effect on fuel consumption (as well as the occasional engine start for heating - not often, or for long on mine as it's a 4hs).

Thoughts and additions?