MPG efficiency figures further from 'real world' than ever
Discussion
Manufacturer MPG figures have always been a little ambiguous, but with the rise of PHEV (amongst other factors) these figures are becoming increasingly obsolete and further from real world. This can be both higher and lower, especially with home charging wildly affecting a consumers observed efficiency. It is now getting the point I rarely look at the published efficiency figures before researching new purchases.
Would like to hear from other PH'ers:
1- they have also found published efficiency figures increasingly further from their own real world figures in real-world driving
2- are becoming less interested in these figures on new car purchases
3- what they would change to the testing mechanisms so they could be more closely related to consumers driving habits
Would like to hear from other PH'ers:
1- they have also found published efficiency figures increasingly further from their own real world figures in real-world driving
2- are becoming less interested in these figures on new car purchases
3- what they would change to the testing mechanisms so they could be more closely related to consumers driving habits
Edited by pissonheads on Sunday 5th January 21:57
I do think PHEVs should be tested twice (the second test starting with a depleted battery) to give a better picture of what you're likely to achieve in your mix of driving. The current figures are completely meaningless unless your commute exactly matches the test cycle.
I say that as an owner of one, an Across (Rav4 PHEV), which I rate highly as an all rounder that gives the best of both worlds. If we charge regularly for day to day use we don't use any petrol at all whereas on long trips it's pretty easy to get 50+ mpg which gives you a comfortable hassle free 500 mile touring range.
I say that as an owner of one, an Across (Rav4 PHEV), which I rate highly as an all rounder that gives the best of both worlds. If we charge regularly for day to day use we don't use any petrol at all whereas on long trips it's pretty easy to get 50+ mpg which gives you a comfortable hassle free 500 mile touring range.
Edited by Snow and Rocks on Sunday 5th January 22:32
I don't know why anyone would ever consider manufacturer mpg figures worth looking at.
They might be helpful if you know nothing about cars but beyond that they are meaningless.
No manufacturer has some magic bullet, and if they did they'll sell it to every other manufacturer so within a life cycle or 2 at the most all the same tech is on every car if it provides a reasonable benefit.
So given the approx. weight, size, engine type, engine size and age you can get a fairly good idea what the real world MPG is going to be.
If a vehicle seems to be an outlier with a higher mpg than you'd expect, then chances are it won't materialize in real world driving.
They might be helpful if you know nothing about cars but beyond that they are meaningless.
No manufacturer has some magic bullet, and if they did they'll sell it to every other manufacturer so within a life cycle or 2 at the most all the same tech is on every car if it provides a reasonable benefit.
So given the approx. weight, size, engine type, engine size and age you can get a fairly good idea what the real world MPG is going to be.
If a vehicle seems to be an outlier with a higher mpg than you'd expect, then chances are it won't materialize in real world driving.
Some manufacturers have always been more notorious than others for gaming the test cycles.
For example I recall a test by Autocar or similar some years back between a VW Golf R and the Subaru STI of the time. From memory the official claimed figures were 40mpg for the Golf R and 29mpg for the STI, but on their 'real world' test the Golf did 28 and the STI did 27.5.
For example I recall a test by Autocar or similar some years back between a VW Golf R and the Subaru STI of the time. From memory the official claimed figures were 40mpg for the Golf R and 29mpg for the STI, but on their 'real world' test the Golf did 28 and the STI did 27.5.
Research indicates that the real-world fuel consumption and CO₂ emissions of plug-in hybrid electric vehicles (PHEVs) are often significantly higher than official figures suggest. Studies have found that, on average, PHEVs consume two to four times more fuel and emit substantially more CO₂ in real-world driving conditions compared to their type-approval values.
For instance, a 2020 analysis by the International Council on Clean Transportation (ICCT) reported that PHEVs' real-world fuel consumption and tailpipe CO₂ emissions are approximately two to four times higher than official test values.
Similarly, a 2021 study by the consumer group Which? found that PHEV models were, on average, 61% less efficient in real-world use than official figures suggest.
These discrepancies are attributed to factors such as limited electric-only range, infrequent charging by users, and the additional weight of batteries, which can lead to higher fuel consumption when the internal combustion engine is in use.
The growing body of evidence highlights the need for more accurate testing procedures that reflect typical consumer usage patterns to provide realistic efficiency and emissions data for PHEVs.
For instance, a 2020 analysis by the International Council on Clean Transportation (ICCT) reported that PHEVs' real-world fuel consumption and tailpipe CO₂ emissions are approximately two to four times higher than official test values.
Similarly, a 2021 study by the consumer group Which? found that PHEV models were, on average, 61% less efficient in real-world use than official figures suggest.
These discrepancies are attributed to factors such as limited electric-only range, infrequent charging by users, and the additional weight of batteries, which can lead to higher fuel consumption when the internal combustion engine is in use.
The growing body of evidence highlights the need for more accurate testing procedures that reflect typical consumer usage patterns to provide realistic efficiency and emissions data for PHEVs.
It’s not too bad with modern cars, I’ve found that with mainly motorway miles I’m not too far away.
But if you only do city driving then pure ICE cars will be getting a lot less. The Jazz was the surprising one, being the worst compared to the official figures.
2020 golf 1.5/150 - 45mpg vs 52mpg official
2021 Honda jazz hybrid - 50 mpg vs 62mpg official
2023 Toyota Corolla hybrid - 58mpg vs 64mpg official
But if you only do city driving then pure ICE cars will be getting a lot less. The Jazz was the surprising one, being the worst compared to the official figures.
2020 golf 1.5/150 - 45mpg vs 52mpg official
2021 Honda jazz hybrid - 50 mpg vs 62mpg official
2023 Toyota Corolla hybrid - 58mpg vs 64mpg official
The way CO2 emissions are being calculated for PHEVs has changed as of 1st Jan this year to take into account the huge discrepancy in real world use. Manufacturers have until the end of this year to re calculate. It’s a correction factor to account for how often the cars are plugged in.
This could seriously impact which models remain on sale in the UK I expect, particularly if the current ZEV mandate consultation for allowable hybrids 2030-2035 results in requiring a CO2 cap or fleet average limit.
https://www.autocar.co.uk/car-news/company-cars/so...
This could seriously impact which models remain on sale in the UK I expect, particularly if the current ZEV mandate consultation for allowable hybrids 2030-2035 results in requiring a CO2 cap or fleet average limit.
https://www.autocar.co.uk/car-news/company-cars/so...
Yeah it does seem a bit daft trying to get a single mpg figure that is supposedly indicative of a car's efficiency when it is possible for the car to do a significant distance using no 'g's at all. It's bad enough for pure ICE cars, where a combination of manufacturers gaming the tests and (more significantly IMO), many people's braindead uneconomical driving 'style' means that the official figures can seem like fantasy. With PHEVs you can throw in people like my uncle who never, ever charges his 330e and then complains that 'it's not bad on fuel but nothing like the figures BMW tell you unless you plug it in'. Well yeah. It would be better to give two figures - how far it'll go on battery alone, then what mpg it'll do on the WLTP cycle but starting with the battery as flat as the car will allow it to go. Basically what Snow & Rocks said above.
With hybrids, so much depends on the type of regular driving done, the way the car is set up to change to electric, and the battery range.
I have run a small company fleet for the last 10 years, and all cars have benn either PHEV or BEV.
We got sort of used to PHEV cars from 2016 onwards having a 25 to 45 mile battery range, and so long as they always used the battery first, were dilligently charged every night and were mainly used for shorter commutes or shopping trips, then it was perfectly possibly not to use any petrol at all.
But most of my users were regularly travelling distances to see clients, and frankly the diesel cars the PHEV's replaced gave much better economy thanks to the extra weight of the PHEVs.
Move forwards to 2023, and my MD, who regularly had to cover the country from his home on the Suffolk coast, finally got completely fed up with his BEV Mercedes with a 203 (at best in summer) mile range, leaving his exposed to jeapordy of finding a working charger unoccupied when he needed one, and asked me to change him back to a PHEV. Imagine his shock when the driver delivering the car from a very distant dealership proudly told him that he had covered over 100 miles on battery before it switched to petrol.
To my mind, a PHEV with that sort of battery range is a very interesting proposition, and ought to show decent real world economy if charged dilligently whenever possible.
I have run a small company fleet for the last 10 years, and all cars have benn either PHEV or BEV.
We got sort of used to PHEV cars from 2016 onwards having a 25 to 45 mile battery range, and so long as they always used the battery first, were dilligently charged every night and were mainly used for shorter commutes or shopping trips, then it was perfectly possibly not to use any petrol at all.
But most of my users were regularly travelling distances to see clients, and frankly the diesel cars the PHEV's replaced gave much better economy thanks to the extra weight of the PHEVs.
Move forwards to 2023, and my MD, who regularly had to cover the country from his home on the Suffolk coast, finally got completely fed up with his BEV Mercedes with a 203 (at best in summer) mile range, leaving his exposed to jeapordy of finding a working charger unoccupied when he needed one, and asked me to change him back to a PHEV. Imagine his shock when the driver delivering the car from a very distant dealership proudly told him that he had covered over 100 miles on battery before it switched to petrol.
To my mind, a PHEV with that sort of battery range is a very interesting proposition, and ought to show decent real world economy if charged dilligently whenever possible.
Only ever owned ICE cars, and no hybrids. I've always taken the manufacturers figure and halved it and assumed that's what I'd get.
Not been too wide of the mark.
I don't really drive for efficiency, so halving it to allow for manufacturers lies and also driving it harder than average seems to roughly work out.
Not been too wide of the mark.
I don't really drive for efficiency, so halving it to allow for manufacturers lies and also driving it harder than average seems to roughly work out.
For ICE cars I have always got the figure(s) the manufacturers state. Same for my EV (Leaf) now. Nissan quotes 120-160 miles on the 39KWH battery and that corresponds to the winter/summer range that I see (I actually get a bit more).
The one car I did find lower was a 1.8L Prius which was a bit poor at motorway speeds, but that was back 12 years ago. If you stuck to 60ish it was great, so it would probably suit real life UK motorways conditions now.
The one car I did find lower was a 1.8L Prius which was a bit poor at motorway speeds, but that was back 12 years ago. If you stuck to 60ish it was great, so it would probably suit real life UK motorways conditions now.
Agreed, that there needs to be a depleted battery mpg test for PHEV. The quoted figures are currently pointless. All I want to know is the battery range and the mpg/performance once the battery range is exceeded.
Particularly as there seems to be a huge disparity in the PHEV systems used. Some will completely deplete the battery resulting in a petrol engine hauling around a useless hybrid system with stunted performance and efficiency, whereas others (such as the Rav 4/Across mentioned) maintain a certain level of charge and act like a self-charging hybrid.
Particularly as there seems to be a huge disparity in the PHEV systems used. Some will completely deplete the battery resulting in a petrol engine hauling around a useless hybrid system with stunted performance and efficiency, whereas others (such as the Rav 4/Across mentioned) maintain a certain level of charge and act like a self-charging hybrid.
FamousPheasant said:
Agreed, that there needs to be a depleted battery mpg test for PHEV. The quoted figures are currently pointless. All I want to know is the battery range and the mpg/performance once the battery range is exceeded.
Particularly as there seems to be a huge disparity in the PHEV systems used. Some will completely deplete the battery resulting in a petrol engine hauling around a useless hybrid system with stunted performance and efficiency, whereas others (such as the Rav 4/Across mentioned) maintain a certain level of charge and act like a self-charging hybrid.
What phev doesn't do that ?Particularly as there seems to be a huge disparity in the PHEV systems used. Some will completely deplete the battery resulting in a petrol engine hauling around a useless hybrid system with stunted performance and efficiency, whereas others (such as the Rav 4/Across mentioned) maintain a certain level of charge and act like a self-charging hybrid.
I think you might have just fallen for Toyota's marketing claims.
Snow and Rocks said:
I do think PHEVs should be tested twice (the second test starting with a depleted battery) to give a better picture of what you're likely to achieve in your mix of driving.
Roger Irrelevant said:
It would be better to give two figures - how far it'll go on battery alone, then what mpg it'll do on the WLTP cycle but starting with the battery as flat as the car will allow it to go. Basically what Snow & Rocks said above.
FamousPheasant said:
Agreed, that there needs to be a depleted battery mpg test for PHEV.
This is exactly what happens; PHEVs are tested with a flat battery, but the figure that gets published is a combination of this value and the value obtained from testing with a fully charged battery.I don't know what the rules are about what must / may / must not be published, but manufacturers absolutely do have separate emissions and fuel consumption figures for depleted and charged battery tests
Edited by deadtom on Monday 6th January 12:20
A colleague bought an Outlander PHEV years ago and worked out that fuel economy once the battery was depleted was averaging in the low 20s! I remember finding it funny because at the time I was driving a 4.2TD straight six full size Land Cruiser and it was (marginally) more economical.
As I said above though, the Toyota system is very impressive and also remarkably simply and cleverly engineered. 306 bhp, 60 in 5.5s, 50m EV range for near free daily driving, 50 mpg+ and 500+ mile touring range that works out cheaper than public charging. Certainly lives up to the marketing for me.
As I said above though, the Toyota system is very impressive and also remarkably simply and cleverly engineered. 306 bhp, 60 in 5.5s, 50m EV range for near free daily driving, 50 mpg+ and 500+ mile touring range that works out cheaper than public charging. Certainly lives up to the marketing for me.
e-honda said:
FamousPheasant said:
Agreed, that there needs to be a depleted battery mpg test for PHEV. The quoted figures are currently pointless. All I want to know is the battery range and the mpg/performance once the battery range is exceeded.
Particularly as there seems to be a huge disparity in the PHEV systems used. Some will completely deplete the battery resulting in a petrol engine hauling around a useless hybrid system with stunted performance and efficiency, whereas others (such as the Rav 4/Across mentioned) maintain a certain level of charge and act like a self-charging hybrid.
What phev doesn't do that ?Particularly as there seems to be a huge disparity in the PHEV systems used. Some will completely deplete the battery resulting in a petrol engine hauling around a useless hybrid system with stunted performance and efficiency, whereas others (such as the Rav 4/Across mentioned) maintain a certain level of charge and act like a self-charging hybrid.
I think you might have just fallen for Toyota's marketing claims.
Certainly some of the Stellantis PHEV systems are pretty poor on a flat battery. For example the Alfa Tonale:
https://www.autocar.co.uk/car-review/alfa-romeo/to...
32mpg and an extra 2.5secs to 60mph with a flat battery.
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