Poor And I Mean Poor Mpg, And Tyre Pressures In Winter Tyres

[Nicolai]

I am really anticipating traffic, trying to use stay in EV mode (car regulates this, not me) and the average includes some A road (50 mph) and motorway driving at 60 mph.

Best autobox I've ever used and quite good mpgs on motorways (60-70 mph) in summer. Love the boot with no load lip. Love CC.

[Ten Ninety]

There is no doubt that this car is built to crawl around commuter land and is probably the reason why we see such widely varying figures from people. Much depends on where you take your car. Heavy traffic is good, the open country is bad for fuel consumption, bad being a relative term of course. Oddly enough this is the opposite of what one would expect from a normal car.

I would respectfully suggest that this is only the case if you look at the periods of time spent in congestion and the open road in complete isolation. I guess many people do this; it's a natural consequence of having all that information on the MFD. For example:

• The driver encounters heavy traffic and the car switches to milkfloat mode whilst creeping along. During this time, the driver sees the instant mpg meter stuck on max and watches the average mpg going up on the MFD. They therefore make a not-unreasonable assumption that the car is giving its best economy under these conditions.
• When the traffic clears and the driver returns to the open road, the ICE of course has to 'pay back' the Battery and diverts power to charging. This causes the instant mpg readouts to be lower, which means the driver sees the average mpg drop again. This confirms their belief that the open road is 'bad' for fuel consumption.

In reality, if the heavy traffic was taken out of the equation then there would be no inefficient 'robbing Peter to pay Paul' between the ICE and the Battery, resulting in a higher overall average for the whole journey. Assuming, of course, that they are driving on the 'open road' in a suitably economical manner and not thrashing along.

As an additional factor, in my experience the more time you spend in milkfloat mode (and I mean actually under electric power, not warp-stealth or coasting) then the bigger the difference between the optimism of the on-board average mpg reading and reality. If all the driver ever uses is the on-board readouts then this will perhaps also steer them towards the belief that town driving is better for economy.

[Aceshigh84]

Agreed. When I first got the car I used to be one of those drivers - how much mpg am I getting right now, and now, and now.

Now I am happy if I can average as close to 60 on the computer per tank full.

I have found that it is luck of the draw most of the time, with factors such as traffic, do you get stuck at lights, does the car in front stop you to turn right etc all playing a small part in negatively affecting that single journey's mpg reading.

Also, there are times when the previous journey was unlucky, but it leaves me with a full Battery, so the next journey I can be on Battery all through the estate roads and onto the main road before the engine fires up. On a cold winters morning this does wonders for the mpg (as long as you then let the engine & oil warm up properly before going into the power band).

Compare all that to a normal petrol or diesel where no matter what time year, day, traffic condition etc is always consuming fuel and I believe that in most circumstances the hybrid is the more efficient overall.

[Ratho1]

In general I would agree with you Jay but even Toyota (read EU cycle ) do not claim any mpg advantage to driving on the open road. Most of the time the engine is doing the work and pulling along the batteries. In town it is the opposite so the normal variation as seen on a pure petrol car is evened out.

Grumpy claims 70-75 mpg from his Prius on the open road in summer. If true that is excellent and is certainly better than I anticipate from my Auris with stupid 17" wheels. It all comes back to that old adage, ignore the computer and do a calculation based on tank to tank fill ups. It's the only way to get an accurate average.

Grumpy, I can only assume that your town average of 50 mpg is caused by a lot of short journeys ( < 5 miles ) and or stopping and starting. That would be the case with any car but in a Prius size that is good. Hence my use of the term "relative". The hybrid system overall beats any alternative at the moment, except perhaps the Ampera system, which is extraordinarily expensive to buy thus losing the point of it all.

[Ratho1]

Hi Colin. My car is only 3 months old. As a matter of interest, how many miles do you have to do before the Battery is fully loaded ? I've done regular 50 mile runs and it never is. It seems to float between half and 3/4 full all the time, which I assumed was normal. Consequently the next day the engine fires up as soon as I have backed out of the garage. Or is this just the time of year ( 5-8c) ? Maybe this is why I struggle to beat 50 mpg, which isn't bad for this time of year but I did anticipate getting nearer 60. You've got me wondering now if the circuitry isn't set properly.

[Grumpy Cabbie]

Ten Ninety, you're so right. It used to drive me bonkers in the taxi job when I'd say I'd get a true 50 mpg in town and passengers would laugh and tell me their Ford ***** (or whatever it was), would get 65 etc. It might driving through town after they'd done a long drive on an A road first, but it certainly wouldn't get more than 35 mpg if they were to spend 10 hours a day in that use.

I remember many a time in my diesel Peugeot watching the mpg average (which i'd reset at every fill up every other day!) slowly drop every time at the lights 32.8....32.6....32.4, then you'd set off and you're down to 28.5, stop at the lights again and 27.9....27.5. It was scarey how quickly it would fall. With the Prius the engine is mostly off when stationary, when slowing down and in slow traffic and it was the addition of all those times that you get the benefit of the hybrid system. A fellow taxi driver had a petrol Avensis automatic and he'd struggle to get over 23 mpg in town use. My hybrid got double!

People also forget that the Prius engine isn't a normal petrol engine and thus it gets better mpgs when on a run on an A road or the motorway. Then you get the addition of the hybrid still offering some assistance even at those higher speeds and that's how you get 60-75 mpg at 50, 60 or 70 mph with ease.

[Aceshigh84]

As far I am aware you cannot fill the Battery 100% by driving, the only time I manage it is when I'm going down a long hill lightly giving the brakes to put as much regen as possible in to the Battery. Even then, the computer will decide when it has had enough and it won't let you charge anymore and will switch to the normal brakes. When driving normally you will never see the top two bars full, or the bottom two empty.

As for the engine running straight away, that could be any number of things: is the Battery "empty" (only 2/3 bars full), have you got the climate control on auto (and set to provide heat), have you switched on the window demist.

I have gotten into the habit of always pushing the ev button when I start the car, if there is enough charge the car will let me stay on ev, if not the engine starts up a few seconds later. I hardly use the climate control from a cold standstill (the seat heaters are just as good), and I try not to use the front window demist unless I really have to. Being in a garage you should be fine without the demisters. Some people just leave the cc off and manually set fans low speed pointing the windows.

One last thing, when on ev mode in really cold weather from a cold start, the car will drop out with the excessive acceleration warning when you get about 75% of the green eco band. This has caught me out a couple of times on junctions because it is the only time I have ever known the car to actually hesitate while it switches to the engine.

[Grumpy Cabbie]

Hi Colin. My car is only 3 months old. As a matter of interest, how many miles do you have to do before the battery is fully loaded ? I've done regular 50 mile runs and it never is. It seems to float between half and 3/4 full all the time, which I assumed was normal. Consequently the next day the engine fires up as soon as I have backed out of the garage. Or is this just the time of year ( 5-8c) ? Maybe this is why I struggle to beat 50 mpg, which isn't bad for this time of year but I did anticipate getting nearer 60. You've got me wondering now if the circuitry isn't set properly.

It is said it takes about 15,000 miles before the car is fully run in and achieving its best economy. I'd agree with that.

Also it is very important to ensure your tyres are at the correct pressures. Many dealers seem to insist on filling them to 30 psi al round, when some models require 33psi and some 35psi. Tyre pressures make a BIG difference. Check them every couple weeks as temperature makes a difference.

Don't try and out smart the hybrid system. Trying to keep it in electric will give immediate improvement in economy BUT will then cause an overall drop as the car has to run the engine more to top up the lower Battery. Drive normally and gently and let the car work it out (it really does) and you will get good economy. I remember being told that years ago when I got my Prius and ignored it. I'd then find I got better mpg's if I was distracted from my mpg quest (such as talking with a passenger).

Your economy will be lower in winter. I found Eco Mode made a slight improvement in town use as it switches the engine off earlier, reduces heat and a/c levels and restricts the accelerator. But in winter it will take longer to heat the car up. Your compromise - do you want it warmer or more efficient? :)

The car gets the heat from the engine. In summer it gets the a/c from the Battery. In winter a hybrid is less economical than it is in summer but it is still much more economical than a petrol or diesel of similar size overall. Wait until summer!

[Nicolai]

15,000 miles to be run in? Why does a hybrid require longer run-in than a conventional car?

[Aceshigh84]

Maybe because in a normal car the engine and associated components are in use from day one all the time, yet because of the hsd in a hybrid they are not, so they take longer to run in.

[Joseph D]

As far I am aware you cannot fill the battery 100% by driving, the only time I manage it is when I'm going down a long hill lightly giving the brakes to put as much regen as possible in to the battery. Even then, the computer will decide when it has had enough and it won't let you charge anymore and will switch to the normal brakes.

This is true, the only time you will get the top bar filled is going down an incline, with or without additional regen through braking. It depends on the length and gradient of the decline.

When driving normally you will never see the top two bars full, or the bottom two empty.

You should be able to get green bars regularly when driving, though. The key is, as GC says, not to try and out smart the system. You generally won't be able to.

I noticed a while ago that I seemed almost never to get green bars, like I remembered I used to and then one day the 12v Battery gave out (in my Prius). I replaced it myself with a 45aH Bosch S4 155 Battery from Europarts and immediately my mpg's jumped by about 10 and I again started to stay in the green range much more frequently.

So, if you are not seeing green bars on your HV in the MFD regularly, then my advice would be to check your 12v Battery with some thorough tests. It may not be fully dead, but it may well be on its way out.

HTH.

[Ten Ninety]

In general I would agree with you Jay but even Toyota (read EU cycle ) do not claim any mpg advantage to driving on the open road. Most of the time the engine is doing the work and pulling along the batteries. In town it is the opposite so the normal variation as seen on a pure petrol car is evened out.

Grumpy claims 70-75 mpg from his Prius on the open road in summer. If true that is excellent and is certainly better than I anticipate from my Auris with stupid 17" wheels. It all comes back to that old adage, ignore the computer and do a calculation based on tank to tank fill ups. It's the only way to get an accurate average.

You're right about the EU cycle being equivalent for urban and non-urban but, as we know, that doesn't exactly reflect reality. In summer time, as GC has indicated, it is easily possible to exceed the EU figures for mile after mile on the open road whereas the urban figure can only be achieved for relatively short durations. These cars can do so much more than just 'pull along the batteries' on the open road; I don't think that's a very fair description of how they work at all.

I should also point out that (for the moment at least) I'm still on stupid 17" wheels myself. They might be a daft choice for Toyota to have fitted, but they don't make it impossible to get 75 or even 80+ mpg on a good summer run with the right dose of luck that Colin described earlier.

As you will undoubtedly have realised, I'm a bit of a saddo when it comes to economy. I've spent a long time researching, applying and practising different techniques over the years; firstly in a 3-cylinder diesel then a turbo petrol and now a hybrid. If you're not happy with the economy you're getting in a hybrid specifically then it might be worth putting some hours in, reading about how the Americans do hybrid hypermiling; there's a vast tract of knowledge out there which is sometimes counter-intuitive and often inappropriate for UK roads, but which can still make a dramatic difference to how you drive and the economy you can realistically begin to achieve.

[Joseph D]

One last thing, when on ev mode in really cold weather from a cold start, the car will drop out with the excessive acceleration warning when you get about 75% of the green eco band. This has caught me out a couple of times on junctions because it is the only time I have ever known the car to actually hesitate while it switches to the engine.

I'd advise against this practice of forcing EV mode unless you can replenish the Battery by going down a hill. Inevitably it will cost you more in the long run as the Battery energy will eventually have to be replaced by the ICE, and this is an inefficient way to use energy. It will hurt your mpg's.

Just my two pence worth.

[Aceshigh84]

Yeah, I can totally agree with that statement.

I should probably say that what I say I do suits me based on my own findings when driving on roads and in areas that I know, when I know what terrain is coming up etc.

When I leave my house I have about half a mile of estate roads and then a 30 limit main road where I join at a junction right onto a section with lights that are invariably at red. The point being I don't see above 20mph for a while, so I am happy forcing ev mode if I can.

After the lights it is a straight run at 30mph for another half mile or so, then 50mph limit dual carriageway and 40mph uphill until the next village. On this stretch the car has to use the engine and I more than make up the charge I used at the first bit.

By this time the engine is nicely warmed up for me to use the climate control and enjoy what the car has to offer for the next 30 odd miles of my commute. The rest of the way I let the car decide how it wants to handle power distribution.

I think the main problem is that some people buy the car expecting to jump in and drive off and get 70mpg from one. When they don't, they read forums like this where some get good mileage and some get really good mileage and they think there is a problem with the car.

Everyone is different, and has different commutes etc, it just takes time to find what suits you and your car best.

[Cyker]

One thing that I like about the new Volvo hybrid is that you can override the leccy side of things, so if you are anticipating, e.g. a lot of slow/town driving, you can force it to use the diesel engine exclusively and charge the Battery instead of operating as a shared discharge, so that when you get to that section the diesel engine can be switched off and the car run on the batteries alone.

I think Toyota will have a fight on their hands against the Volvo as it blows the Auris Tourer and Prius+ out of the water; The biggest downsides are the insanely high cost and whether Volvo have been able to overcome the problems of using a diesel engine on a low duty-cycle (Diesel engines really hate being cold).

[Ratho1]

Hi Guys,

Some very good advice here and many thanks for that.

As you may have gathered, I'm still learning how to get the best out of this very interesting and enjoyable to drive, car. Some things I still haven't tried yet, the CD player for one. I rarely listen to music in a car on short journeys, too much distraction.

I haven't tried to run on EV alone. The dealer advised against it and said it was pointless. On the whole I tend to agree.

As a matter of general practice I have always switched off the Climate Control system until I needed it. Right now I am enjoying the seat warmer though, as Colin does :o .

My first long run ~150 miles, wont be until mid April. Then I'll have some idea about it's capabilities over distance.I have tested the power button and found it quite impressive, except that I think it's location is wrong. I have to take my eyes off the road to find it. Not a good idea, especially when trying to overtake. It would be better placed on the steering wheel.

[FROSTYBALLS]

With a list price of approx £44,500, the Volvo V60 Hybrid is in a different market sector to the Auris Touring Sports Hybrid and Prius +. In fact the Lexus RX450h has a similar list price.

The following Telegraph article raises one fairly important question - http://www.telegraph.co.uk/motoring/car-manufacturers/volvo/10191687/Driven-Volvo-V60-Plug-In-Hybrid.html

[Grumpy Cabbie]

With a list price of approx £44,500, the Volvo V60 Hybrid is in a different market sector to the Auris Touring Sports Hybrid and Prius +. In fact the Lexus RX450h has a similar list price.

The following Telegraph article raises one fairly important question - http://www.telegraph.co.uk/motoring/car-manufacturers/volvo/10191687/Driven-Volvo-V60-Plug-In-Hybrid.html

I agree. There's also a BIG difference between the Prius and the plug in Volvo (other than about it being double the price).

[Nicolai]

So, just checked tires pressures. I'm pretty sure, they were underflowed. See how it goes now. I must say I find the ride in the auras a bir firm/harsh compared to my Swift from 2007. But maybe a lot has happened to car suspension since... Maybe, today, a harder setup is the norm....

[Grumpy Cabbie]

What were the pressures and what did you put them to?

[Nicolai]

I'm not entirely sure what the pressures were before put to "ECO specs" (front: 37.7 psi, rear: 36.3) but I'm positive that at one point on my right front tire the computerized pump displayed 2.2 bar / 31.9 psi. Something in me hopes that this was due to me having, accidentally let out some air prior to this reading, however, whilst it IS possible that some air may have accidentally escaped, I don't think this would ever justify the difference. The pump pumped in a lot more air than I heard escaping when putting the "blower" on the wheels/pulling it off.

[Joseph D]

I'm not entirely sure what the pressures were before put to "ECO specs" (front: 37.7 psi, rear: 36.3) but I'm positive that at one point on my right front tire the computerized pump displayed 2.2 bar / 31.9 psi. Something in me hopes that this was due to me having, accidentally let out some air prior to this reading, however, whilst it IS possible that some air may have accidentally escaped, I don't think this would ever justify the difference. The pump pumped in a lot more air than I heard escaping when putting the "blower" on the wheels/pulling it off.

Well Nicolai, that will make a difference. Just keep monitoring once a week to confirm that you do not have a leak in one of your tyres, and see if having your tyres all at the correct pressure does in fact help your fuel economy.

[Joseph D]

One thing that I like about the new Volvo hybrid is that you can override the leccy side of things, so if you are anticipating, e.g. a lot of slow/town driving, you can force it to use the diesel engine exclusively and charge the battery instead of operating as a shared discharge, so that when you get to that section the diesel engine can be switched off and the car run on the batteries alone.

This thinking is counter-productive and not borne out in evidence.

It can be done in Toyota hybrids as well, but it not recommended, unless you know something (like a long hill descent coming up ahead) that the computer doesn't.

Slow/town driving is exactly when you would be wanting to use electric power if possible, but if you haven't built up sufficient Battery reserve so that the system computer runs in HV mode anyway, then you should let the computer juggle the ICE and leccy modes as it sees fit and not override it.

Using the diesel engine to charge the batteries later will only result in about 30% efficiency so is a very expensive and inefficient way to go about the process. Your mpg's will not benefit from this practice. It is best to let the engine management computers control the system to eke out the best efficiency.

[Ratho1]

Nicolai, on 02 Feb 2014 - 19:16, said:

I must say I find the ride in the auras a bir firm/harsh compared to my Swift from 2007.

It's almost certainly because you are running on those ridiculous 17" low profile wheels that have been fitted. I don't know why Toyota do this when they have 15" high profile available on the Icon version. You would also get 10% better fuel consumption with the smaller wheel.

[Nicolai]

Once again: my TS has 15 inch wheels...