C-HR real world MPG

[FROSTYBALLS]

4 hours ago, AndyRC said:

 I wonder if Toyota will offer a bigger Battery option on the C-HR ? 

The C-HR is in it's fifth year of production, so wouldn't have thought Toyota will offer a larger Battery until the second generation or replacement is due.

[AndyRC]

Took a 2.0L C-HR Design out for a decent test drive of nearly 60 miles , mix of M Way , A/B roads and some town driving , drove at the relevant speed limit and the onboard computer was reading 60.7 mpg,  even  if the computer is 5% optimistic that’s still an impressive 57.7 mpg. The 2.0l engine never felt underpowered and overall very impressed with the car👍

[Charles2021]

I think this requires a little more explanation, I reset the trip computer, filled the tank to full and went on a 150 mile round trip, 90% motorway at a constant 55mph.The trip computer shows an average of 74mpg. Fill the tank full again, do the calculation after working out the fuel used, result 55mpg???

[MyOpinionIsWorthless]

On 6/13/2021 at 4:45 PM, AndyRC said:

Does anyone know the science as to why a bigger wheel diameter reduces fuel consumption? The overall wheel &tyre  diameter does not vary significantly as wheel diameter increases , tyre profile decreases keeping things equal. Bigger alloy does not necessarily equate to more weight , I’ve seen 19 inch oem alloys weigh slightly less than the same design 18inch oem.   I can see how a larger overall mass (wheel and tyre) will decrease MPG but not why a 17 inch will be better than a 19 inch if overall diameter and weight are equal. 🤔

It’s not all about the mass it’s about the inertia. Or rather the energy require to move the wheel through a complete rotation. 

[AndyRC]

2 hours ago, Charles2021 said:

I think this requires a little more explanation, I reset the trip computer, filled the tank to full and went on a 150 mile round trip, 90% motorway at a constant 55mph.The trip computer shows an average of 74mpg. Fill the tank full again, do the calculation after working out the fuel used, result 55mpg???

Agree that the only accurate way is to calculate based on “brim to brim” refills. I always do this with cars I own and compare with the car computer. These have always been optimistic, worst being a Vauxhall Astra at 14% optimistic and the most accurate being on a Golf R  2% optimistic. 

[TonyHSD]

On 6/14/2021 at 7:22 PM, AndyRC said:

Agree that the only accurate way is to calculate based on “brim to brim” refills. I always do this with cars I own and compare with the car computer. These have always been optimistic, worst being a Vauxhall Astra at 14% optimistic and the most accurate being on a Golf R  2% optimistic. 

To get the real world average from the car computer you will need to drive the car more or on few occasions. Because if only done a trip of 150 miles you might had achieved 74mpg average indeed, however before that and after that the real world average will adjust since the car will get used in not so ideal conditions, start at cold, traffic jams, climbing uphill, waiting on traffic lights etc, using air con, the latest uses a lot of Battery power and when on and it’s working hard to cool of the cabin the ice kicks in a lot more often to preserve the Battery for propelling the car and ice uses petrol even when is running as a generator. There are many factors to add to do overall picture of fuel consumption. My car is ultra accurate, but I drive a lot and on long journeys in pretty much all conditions and when compare pump with dashboard are almost equal. 👍

[Charles2021]

Hi Tony, your reply doesn't really make sense. If I drive 150 miles and measure the amount of fuel used I will be able to calculate the exact mpg, anything before or after that journey is not used in the calculation the result is the exact average (mean) mpg over that particular journey. I assume the trip computer makes exactly the same calculation i.e. it measures the fuel used and the distance travelled for that particular journey and then calculates the average mpg, the computer is obviously reset at the start of the journey so everything before and after is not brought into the calculation. The mpg results should be the same in both cases, allowing a few percent for any inaccuracy in determining the full tank level. 

[TonyHSD]

2 hours ago, Charles2021 said:

Hi Tony, your reply doesn't really make sense. If I drive 150 miles and measure the amount of fuel used I will be able to calculate the exact mpg, anything before or after that journey is not used in the calculation the result is the exact average (mean) mpg over that particular journey. I assume the trip computer makes exactly the same calculation i.e. it measures the fuel used and the distance travelled for that particular journey and then calculates the average mpg, the computer is obviously reset at the start of the journey so everything before and after is not brought into the calculation. The mpg results should be the same in both cases, allowing a few percent for any inaccuracy in determining the full tank level. 

Ok, let’s accept my theory makes no sense., where the difference then is coming from 74mpg against  55mpg?
Have you noticed sometimes this display numbers are very inaccurate and the car needs more time to settle., shortly after reset they can be very optimistic if you were driving efficiently and on a long trip (like was in your case 55mph motorway ) but if you were driving on mountain roads and climbing uphill those numbers will be around 30’s where your actual mpg would have been around 45. 
These odo numbers are not always accurate, and the car needs more time after reset and driving in various conditions to settle and be as close as possible to the real world.,and then the numbers will stuck again and  this perhaps is a good reason to use old school brim to brim pump to pump measures. 👍

[Charles2021]

Of course the trip computer will use a rolling average although I don't know what distance frame is used. In my example this would not matter as 95% of the journey was on the motorway at a constant 55mph. An earlier post said that in his experience all trip computers were between 2 & 14% "optimistic", in my example it is 32% which seems very high. I would think the computer will measure distance and consumption accurately to within a few percent so all I can assume is that the figures are deliberately inflated. I'm going on a 100 mile trip later, no motorway, so I'll try the measurement again. Filling to the "brim" is prone to error although not enough to cause this difference.

[AndyRC]

37 minutes ago, Charles2021 said:

Of course the trip computer will use a rolling average although I don't know what distance frame is used. In my example this would not matter as 95% of the journey was on the motorway at a constant 55mph. An earlier post said that in his experience all trip computers were between 2 & 14% "optimistic", in my example it is 32% which seems very high. I would think the computer will measure distance and consumption accurately to within a few percent so all I can assume is that the figures are deliberately inflated. I'm going on a 100 mile trip later, no motorway, so I'll try the measurement again. Filling to the "brim" is prone to error although not enough to cause this difference.

You will see different readings between the onboard and calculated depending on the type of journey completed for that tank of fuel.  I always kept a detailed record of milage and fuel used for car expenses at work as we we paid a flat rate per mile. If I bettered the rate I was in profit, didn’t hit it I was losing out.  My experience was that once you had sufficient data to smooth out anomalies , say 10 full tank refills, the difference between the onboard and calculated readings settled down to a pretty consistent % difference.  I never managed to get a better calculated mpg than the mpg the car was showing. So far we’re 99% there with getting a 2.0l C-HR , not just on economy but the way the car drives , particularly in town and stop start urban situations. 

[Charles2021]

Andy, that really doesn't explain it. On my 150 mile trip the "fill to the brim" is correct to within a few percent. The trip computer was reset at the start of the trip so how, what (and why) was the computer measuring during the trip to give a 33% better mpg figure?

[AndyRC]

1 hour ago, Charles2021 said:

Andy, that really doesn't explain it. On my 150 mile trip the "fill to the brim" is correct to within a few percent. The trip computer was reset at the start of the trip so how, what (and why) was the computer measuring during the trip to give a 33% better mpg figure?

Charles.  I can’t explain that anomaly and 33% is a long way out.  I’ve found most onboard computers are usually around 4/5% optimistic.  Do you keep records and do a comparison check on every refill? I’ve been running my son’s old Fiesta EcoBoost for a few months and on very similar types of journeys I’ve seen variations between 2% to  6% and that’s without any Hybrid technology to confuse things, on average it’s around 3% optimistic. Maybe monitoring over a longer period will highlight if yours is always 33% out.  Our C-HR will get used for business so expecting to be doing 15k to 20k a year so that should give some good long term data. 

[GBgraham]

 

This was taken from the MyT app. This was the return leg but the whole trip regularly equates to 65mpg by the trip computer. I've never felt the need to do a full to full calculation. The only thing that surprises me is that these days of the smaller although more powerful and economical engines is that Toyota has decided to stick to the 1.8 and 2.0 engines.  

 

[TonyHSD]

1 hour ago, GBgraham said:

 

This was taken from the MyT app. This was the return leg but the whole trip regularly equates to 65mpg by the trip computer. I've never felt the need to do a full to full calculation. The only thing that surprises me is that these days of the smaller although more powerful and economical engines is that Toyota has decided to stick to the 1.8 and 2.0 engines.  

 

Toyota did the right thing to keep bigger displacement engines, they have higher miles resource plus they work in combination with electric motors which takes the harder part of the work of the engine and help efficiency. Small turbo charged engines usually equals shorter life.. plus these are only efficient when not loaded. 1.2t perhaps it’s not a bad one for an average user who drives max of 10k miles a year and likes a manual shifting. 

 

[Cyker]

It's a bit deceptive because, although they are higher displacement on paper, in reality because of the whole Miller/Atkinson-cycle thing, they actually operate more like smaller engines; I estimate the ICE in the 1.5 hybrids is on par with a 1.0, and the 1.8 is closer to a 1.3!

It's because they push out some of the air-fuel charge, so although the cylinder is e.g. 0.5L, it pushes out maybe 0.1-0.2 of that before closing the valve and igniting it. The idea is you burn, say, 0.3L of charge, but take 0.5L of energy extraction, because the longer your expansion stroke the more energy you can extract from the burn - It's partly why diesels are so efficient, because they can have longer expansion strokes than any other type of reciprocating engine, and why petrol exhaust is so much hotter than diesel (Because their relatively short expansion stroke can't extract as much of the burn energy, so it just goes out the exhaust).

Real Atkinson-cycle engines have a very complicated linkage that really makes the compression and expansion strokes different lengths, but faking it with delayed valve-timing like the Miller-cycle is much easier and more reliable.

 

Also, what's this about the 19's getting better mpg than 17s?? Usually it's the other way around!

One of the reasons I'm going from 17s to 15s in my Mk4 is to improve mpg (But also mainly because I have a small heart attack every time I fail to dodge a pothole! What fool thought low-profile tyres would be a good idea on a non-performance car?! Have they not seen the state of our roads?!)

 

[AndyRC]

12 hours ago, Cyker said:

It's a bit deceptive because, although they are higher displacement on paper, in reality because of the whole Miller/Atkinson-cycle thing, they actually operate more like smaller engines; I estimate the ICE in the 1.5 hybrids is on par with a 1.0, and the 1.8 is closer to a 1.3!

It's because they push out some of the air-fuel charge, so although the cylinder is e.g. 0.5L, it pushes out maybe 0.1-0.2 of that before closing the valve and igniting it. The idea is you burn, say, 0.3L of charge, but take 0.5L of energy extraction, because the longer your expansion stroke the more energy you can extract from the burn - It's partly why diesels are so efficient, because they can have longer expansion strokes than any other type of reciprocating engine, and why petrol exhaust is so much hotter than diesel (Because their relatively short expansion stroke can't extract as much of the burn energy, so it just goes out the exhaust).

Real Atkinson-cycle engines have a very complicated linkage that really makes the compression and expansion strokes different lengths, but faking it with delayed valve-timing like the Miller-cycle is much easier and more reliable.

 

Also, what's this about the 19's getting better mpg than 17s?? Usually it's the other way around!

One of the reasons I'm going from 17s to 15s in my Mk4 is to improve mpg (But also mainly because I have a small heart attack every time I fail to dodge a pothole! What fool thought low-profile tyres would be a good idea on a non-performance car?! Have they not seen the state of our roads?!)

 

One can only assume the mover to larger wheels is a marketing/aesthetics thing. I’ve never driven a car that rode better on a larger wheel than a smaller one. This all seams bizarre if larger diameter wheels increase  fuel consumption and emissions when manufacturers are trying to reduce their overall fleet average emissions 🤷‍♂️  

[AndyRC]

14 hours ago, TonyHSD said:

Toyota did the right thing to keep bigger displacement engines, they have higher miles resource plus they work in combination with electric motors which takes the harder part of the work of the engine and help efficiency. Small turbo charged engines usually equals shorter life.. plus these are only efficient when not loaded. 1.2t perhaps it’s not a bad one for an average user who drives max of 10k miles a year and likes a manual shifting. 

 

I’ve only tried the 2.0l version and have found the performance to be more than adequate and overall  feeling very relaxed and unstressed. 

[Catlover]

Those saying larger wheels are fitted by manufacturers are right in saying “it’s the looks”.  Real life scenario….. I travelled 100 miles to a Toyota dealer to get the used car I wanted, a Hypersonic Red Toyota Prius with leather seats and JBL Speakers - which meant I needed an Excel. When we got to the dealer there was two Hypersonic Red Prius next to each other, the Excel and a Business Edition.  The Excel was on 15” wheels (which must have been optional purchase) and the Business Edition was on its standard 17” wheels. So I am looking at the Excel because it was a spec I wanted, including 15” wheels - fed up with the hard ride on the 17” wheels standard on my Prius Gen3 I was trading in.  The wife is looking at the Business Edition saying I like this one”, so I asked why and it was because the wheels look nicer on the Business Edition. And I agreed, the 17” looked nicer, but no way was I getting the B.Ed with 17”.   Not even up for discussion. The Excel on 15” was what we bought.

[Charles2021]

Guys, I think I've got to the bottom of the mpg issue. I assumed that when you reset the average mpg displayed on the small sceen it did exactly that, it doesn't. You have to go into the trip information and past history on the main display and also clear the data there, note, it takes several "clear" presses to reset all the data, then check the small screen display has also been reset. I've just been on a 124 mile trip, no motorway, A roads, hilly in the Peak District. Computer shows 66.7mpg, fill to brim calculation is 62.0 mpg, which sounds about right. 7.6% optimistic.

[AndyRC]

2 hours ago, Charles2021 said:

Guys, I think I've got to the bottom of the mpg issue. I assumed that when you reset the average mpg displayed on the small sceen it did exactly that, it doesn't. You have to go into the trip information and past history on the main display and also clear the data there, note, it takes several "clear" presses to reset all the data, then check the small screen display has also been reset. I've just been on a 124 mile trip, no motorway, A roads, hilly in the Peak District. Computer shows 66.7mpg, fill to brim calculation is 62.0 mpg, which sounds about right. 7.6% optimistic.

Glad that you got to the bottom of the significant difference , will be interesting to hear what the difference is over several refills and different driving conditions. 

[GBgraham]

On 6/18/2021 at 10:07 AM, AndyRC said:

I’ve only tried the 2.0l version and have found the performance to be more than adequate and overall  feeling very relaxed and unstressed. 

 

On 6/17/2021 at 7:50 PM, TonyHSD said:

Toyota did the right thing to keep bigger displacement engines, they have higher miles resource plus they work in combination with electric motors which takes the harder part of the work of the engine and help efficiency. Small turbo charged engines usually equals shorter life.. plus these are only efficient when not loaded. 1.2t perhaps it’s not a bad one for an average user who drives max of 10k miles a year and likes a manual shifting. 

 

Thanks for your thoughts and observations, this the first petrol ICE I've owned apart for a few classics for about 45 years and my first CVT. Although I do wonder how a diesel engine would have performed in conjunction with the hybrid.

 

[TonyHSD]

5 hours ago, GBgraham said:

 

Thanks for your thoughts and observations, this the first petrol ICE I've owned apart for a few classics for about 45 years and my first CVT. Although I do wonder how a diesel engine would have performed in conjunction with the hybrid.

 

Hi, 

there are few cars with that combination although they are not a Toyota products and very different hybrid technology. Some even has a starter motor and gears (Mercedes, Audi) and you can hear the starter is turning the engine. For efficiency owners has complained that a simple diesel is more economical in real world in comparison with their hybrids., perhaps due to the complexity of these hybrid drivetrains. Not sure if it’s going to be healthy for a standard Diesel engine to be a part of the Toyota hybrid system and work under constant stop start conditions., plus the noise, vibrations and overall pollution created by the burning of heavy oil. Diesel burning process is dirty, best way to reduce these emissions is to eliminate that process, no diesel 👌👍

[AndyRC]

We have signed the order for a 2.0L C-HR today which should hopefully be with us in around 2 weeks. As it will get used for business and pleasure , up to 20,000 miles per year,  we will be keeping accurate records of mpg so will be able to report in due course. 

[Cyker]

You're not wrong TonyHSD! In theory a diesel hybrid would be cheaper to run and more economical than any other kind of drivetrain, including BEVs - Could easily get MPG into the hundreds!

The problem is in real life, unless you had some sort of engine heater, the start-stop nature of the hybrid would mean it will never get up to operating temperature, and a cold diesel engine has terrible efficiency. On especially cold days in winter, I could drive my Mk1 diesel Yaris half-way to work before the cold engine light went out!

The only way I could see it working is if it was a tiny 2 cylinder with a mahoosive turbo, as the high load and small displacement would hopefully warm it up fast enough to remain efficient, but if my Mk4 Yaris is anything to go by even that might not be enough as even with the tiny Battery in the Mk4 I've been able to drive in town on Battery only for so long the petrol engine has cooled down to 2 bars!

For me the Mk4 is in the sweet spot - I can hoon it around and still have an average tank mpg in the 70's; Although I've gotten higher MPGs in my old Mk1 D4D, that was on steady motorway runs and not hooning about! I think diesel will still beat it for a long run, but in a mix of town, A-roads and country roads the Mk4 is really strong.

The kicker is my journeys involve hills, and that was one area the Mk3 Yaris Hybrid was awful at - Throw a hill or incline at it and the mpg would tank. Barely seems to make a dent with the Mk4!

The TNGA hybrids really are very good...!

[TonyHSD]

17 hours ago, Cyker said:

You're not wrong TonyHSD! In theory a diesel hybrid would be cheaper to run and more economical than any other kind of drivetrain, including BEVs - Could easily get MPG into the hundreds!

The problem is in real life, unless you had some sort of engine heater, the start-stop nature of the hybrid would mean it will never get up to operating temperature, and a cold diesel engine has terrible efficiency. On especially cold days in winter, I could drive my Mk1 diesel Yaris half-way to work before the cold engine light went out!

The only way I could see it working is if it was a tiny 2 cylinder with a mahoosive turbo, as the high load and small displacement would hopefully warm it up fast enough to remain efficient, but if my Mk4 Yaris is anything to go by even that might not be enough as even with the tiny battery in the Mk4 I've been able to drive in town on battery only for so long the petrol engine has cooled down to 2 bars!

For me the Mk4 is in the sweet spot - I can hoon it around and still have an average tank mpg in the 70's; Although I've gotten higher MPGs in my old Mk1 D4D, that was on steady motorway runs and not hooning about! I think diesel will still beat it for a long run, but in a mix of town, A-roads and country roads the Mk4 is really strong.

The kicker is my journeys involve hills, and that was one area the Mk3 Yaris Hybrid was awful at - Throw a hill or incline at it and the mpg would tank. Barely seems to make a dent with the Mk4!

The TNGA hybrids really are very good...!

Just discovered, the Mercedes E300De has a serious problems with injectors, wide spread and costly repair if out of warranty. Diesel engines cars are more efficient in long motorway trips, however once you mix the journeys as you say with town driving or traffic jams and they loose the lead against the hybrids, plus they do require more maintenance, the diesels of today are not the ones from the past that needed minimum attention and just a clean fuel, now they are  over engineered and complicated tech that are prone to failure or expensive maintenance in relatively short period of time. Toyota hybrids are currently best to buy and own from new if you want ice car, otherwise Tesla and the rest of the bev . Diesel engines should be left for heavy duty machines, tracks, lorries, ferries etc.