Prius Fuel Economy Update

Click on through to the Prius MPG review page to see the latest update. Little improvement with the weather being less cold in the last week. It certainly has been atypical to date. Spring might be here though. Currently averaging just over 53 mpg with the current tank but we have had a couple of longish extra urban runs.

Car Manufacturers May Be Publishing False MPG Figures

I heard an interesting article on today's editipon of You And Yours on BBC Radio 4 - listen to the programme on this link http://www.bbc.co.uk/programmes/b01r5s1r. The programme asked:

... does your car give the fuel economy it was advertised with? No? Well it may not be your driving. New research is blaming the manufacturers.

This may account for why many Toyota Prius owners are disappointed with the actual fuel economy they experience. According to the researcher interviewed on the programme, many manufacturers, especially in Europe, can 'tune' the car that is being tested for the official mpg figure.  I was amazed to hear that they can blank off grills, remove wing mirrors, fit slick tyres, inflate tyres to high pressure as well as other 'tricks' like 'remove' the brakes by lifting off the calipers so that there is no friction contact between disc pads and brake discs. Apparently, the divergence between official mpg figures and actual mpg figurs has been increasing over the years - from about 7% in 2001 to 23% of late. Time to apply some consumer pressure, is it not?

New update to come soon

Been very busy over the winter period but have a batch of latest fuel figures that I will stick up on the blog soon.  Thanks.

The Peril of the First Yellow Bar and Other Things

You know, I think I can summarise the three things that have made the biggest dent in Prius fuel economy as follows:

• Short journeys under 10 minutes
• Starting from cold, in cold weather
• Shoving things on the roof like roof bars and roof boxes

Now, this may seem obvious, but some people may think that a Prius is a special car that can take any kind of load and conditions and still return 60+ mpg. True, the car is fantastic and does return great fuel economy; my bank balance is testament to that. But it is still a machine designed by humans and is fallible.  You have to treat it within the limits of its capability.

Let's take the first bullet point above.  I'm the main parent taking the kids to and from school.  At 2 miles, the journey is too far to walk for a five and seven-year-old, and so we must needs take the car, at least part ways.  Since this is usually the only trips I make with the car most days it means two short trips with cold engine starts.  This is why I've entitled this post "The Peril of the First Yellow Bar and Other Things".  As you may know, the Prius has a real-time "Consumption"display screen that you can see on the LCD panel.  It is a bar chart segmented into 5 minute marks along the x-axis.  Ninety-nine percent of the time I get a low mpg figure for the first 5 minute segment of the journey - the first yellow bar.  (You can see a photo of such a screen on this link on Flickr.)  It usually hovers around the 25mpg mark in this segment.  Ouch!  A yellow peril indeed   If you ask the Prius to do lots of journeys like this then your overall fuel economy will suffer.  Only when doing regular journeys of, say, longer than 15 minutes, will you start to see overall improvement.

Yes, in my opinion, the temperature plays a part too.  In cold weather the engine has to burn more fuel to reach operating temperature.  If you are lucky enough to have a garage to shelter your car then I recommend it, especially over the winter months.  Your engine will reach operating temperature quicker.  The Prius, just like conventional cars, has to burn petrol/gasoline to reach this temperature.  The electric motor plays no part in this.

There is a body of opinion that thinks that sub-30mph speeds don't really adversely impact fuel consumption.  I disagree.  Even at lower speeds my roof bars create aerodynamic drag - a resistive force that wants to pull the car down to a slower speed.  This drag certainly increases in magnitude the faster I drive.  Nonetheless, it is always present and always gnawing away at my fuel efficiency. I do stuff that often require me to have them on.  I do take them off as often as is practicable.  Experience, and the data I gather, has shown this to be prudent.

I hope I haven't scared you off by this post.  That is not my intention.  I love my Prius and the efficiency I enjoy with it. However, I just wanted to show that it is a humble machine at the end of the day that deserves to be treated well in order to get the most out of its fantastic hybrid technology.

Prius MPG Review 16-November-2012

I have been remiss in not committing to an update sooner.  Apologies.  I have updated the chart and table with my most recent mpg data.  You can see them on the 'Prius MPG' page by clicking here or selecting it from the menu bar above.

Your genuine comments are always welcome.  Thanks.

Prius MPG Review 20-September-2012

Well, this is the first of my new look 'Prius MPG Reviews'.  Please click through to the 'Prius MPG' page by clicking here or from the menu bar below the header.  You'll see the latest Prius MPG data there.

Thanks.

New Prius MPG Page Published

Hello!  It has been a few weeks since I last posted an entry on the blog so please accept my apologies. Time for blogging has been squeezed between preparing our house for sale, enjoying the summer holiday with the family and applying for a post graduate degree course.  Phew!

Having mused upon the method I was using to record my Prius mpg and blogged about it here, I have now created a dedicated page - Prius MPG - where I will be updating the Prius mpg data I record.  You can browse to the new page from the menu bar below the header.  Each time there is an update I'll publish a short post to let everyone know.  I hope that this new, and hopefully improved, method and format will be better all round.

Thanks again everyone,
Sean.

Musings on Prius MPG Reviews

You may have noticed that I have not posted an 'MPG Review' post for three weeks or so.  This is with reason. Actually, it is with various reasons.  I fell ill with a nasty head cold, my wife has succumbed too, though in typical stoic woman style she has shrugged it off as "not that bad". To top it off, I have been thinking that my method of recording the Prius MPG is flawed.

Let me explain my thinking.

My method to date has been to note climatic and related data, record it in a table every week, as well as note the average MPG displayed on the Prius LCD display panel.  Now, I have never pressed the "Reset" button on the LCD display.  I just run the Prius, fill up with fuel when I need to and reset the odometer Trip A reading to zero.  Every week I take my latest MPG reading.  The removal of the Thule roof bars has led me to dig around a bit more since I expected there to be more of an evident 'step change'. Instead there has been just a gradual change.  I did notice an increase in the miles per tank as evidenced by the Trip A odometer reading.  Hmm, that is odd I thought.  So I did a manual calculation based upon the distance covered with my latest tank of fuel.  Bearing in mind I calculate in imperial gallons since I am resident in Scotland,I found that I was actually getting 55mpg, not the latest 51.2mpg as displayed on the LCD display. Of course, it becomes clear to me that the Prius readout is because it has been averaging the MPG since the last reset on the display panel button.  Naturally, I will be changing the way I track and report on MPG from now on.  I propose that with every fill up of fuel not only will I reset the Trip A odometer reading but I will reset the fuel consumption reading too. I think this will give a more honest and direct reading of the latest driving conditions and effects upon the fuel economy of the vehicle.

Wish I'd thought of this before but I guess this diary charts a journey of discovery ... and of my own stupidity!  On top of this, it looks like I'll be refitting the roof bars (an easy job) in order to prepare for our holidays down south to England.

Prius MPG Review 29-June-2012

With the roof bars off, the fuel economy has gone back up to 50.9mpg.  In fact, earlier today, on a run to Cupar, the computer displayed average mpg of 51.0.   I am starting to get the fuel economy back to the 54 to 55 range where it was about a year ago (minus roof bars).

One thing I think is going against my favour is that most of my journeys last between 5 to 10 minutes long.  This is to run the children to school - a distance of two miles.  Typically the engine starts from cold, runs to the point where it is warmed up, then, journey over.  I think if I were doing regular, longer runs then I'd see an improvement in fuel economy.  For instance, on a twenty minute run to St. Andrews during the week the mpg for that jorney was in the low 70s.  This was a good straight, long unbroken run on a fairly level road combined with running the engine/hybrid system at optimum temperature - and the results speak for themselves.  There are so many factors affecting this mpg figure, aren't there!

Prius MPG Review 21-June-2012

As I tweeted the other day, the mpg went up to 50.9, then went back down to 50.8, went up again and today went back once more to 50.8.  All in all, no change.  However, I have taken off my Thule roof bars.  Lets see what difference that makes.  Most of the driving, in fact all of it, has been urban driving over the past week.  That, coupled with the low temperatures (is this really summer?), has no doubt had an effect on fuel economy.  Here are the pretty pictures for this week:

Prius MPG Review 14-June-2012

I realise I have not updated recently and am overdue to post the latest mpg results.  Sorry if you have been waiting.  Drum roll please ..... I am now getting 50.9mpg. Here are the stats:

I have been pleased with this improvement, especially considering I have had the 360 litre roof box ounted for a week whilst we were away camping.  (I'll post about that experience in the next day or so.)  I had a comment from reader discostu about his acceleration technique and how he uses the gas/accelerator pedal.  I have been bearing in mind his technique of pressing the pedal down as if there was an egg underneath and trying not to crush it.  However, I know the bigest impediment to achieving greater mpg at the moment for me is the roof bars and I am going to take them off soon.  In fact, I may take a small video of the process of removal.

That's all for now - watch out for a post in the next day or so about our latest camping experience!

Prius MPG Review 01-June-2012

Quick post today.  Mpg has crept up to 50.7mpg. Will update graphs and stats next week. Roofbox back on for camping in Aviemore for the weekend.  The infamous A9 beckons. Give me a toot if you see me.

Prius MPG Review 24-May-2012

The mpg is still sitting at the same this week so my recent improvements in fuel efficiency seem to be tailing off.  The weather has been a tale of two extremes.  The past three days have been glorious; the children have had to get their sun tan lotion on plus suffering constant reminders from me to keep their sun hats on.  Before that, I recollect a discussion with my wife about whether to put the central heating back on it was so chilly.  You really never have a dull moment with the weather in Scotland!

Prius MPG Review 17-May-2012

The past week has been good again with the mpg.  Fuel efficiency has increased again by one decimal point from 50.5mpg to 50.6mpg.  I deflated the tyres down from 41psi all round to 38 at the front and 36 at the back since it is going to my local Toyota dealership tomorrow for a service.  Being nearly six years old now, but still with only 37,000 miles on the odometer, our Prius is due what Toyota refer to as a Full Service.  This will set me back £249 (for an online currency converter click here).  However, compared to other vehicles I've owned (our old XC90 comes to mind), this is small beer.  Check back in a couple of days time to see how well the Ful Service went.

I've included this week's statisitics below, as usual.

Prius MPG Review 10-May-2012

This week's mpg review shows that fuel economy has again improved, now showing 50.5mpg.  This after encountering hail and snow (yes - snow in May) and some very cold temperatures whilst camping near Killin by Loch Tay.  The Prius coped admirably (as always) making the journey easy, comfortable and smooth.  Loaded with four people, luggage and four bikes on the back.

Here are the stats:

And the chart:

Expect a review of my Prius ownership soon, before next week's MPG Review.  In the meantime, happy hypermiling!

Prius MPG Review 03-May-2012

It's gone up to 50.4mpg!

Got to be a quick one today.  Yes, the good news is that the mpg has gone up to 50.4mpg, so I'm very happy.  Temperatures have been slightly better, ranging from 7°C to 12°C.  I also wondered if I should be charting the use of climate control - I always have it on.  Hmm, will need to consider adding it to the stats.


Here they are:

Prius MPG Review 26-Apr-2012

I'm getting really fed up of the weather. I'm sure it is well within the statistical mean temperatrure range, but the temperature has struggled to make double digits, nosing 11 °C at its absolute maximum over the past week.  Feels even colder than this though and we've certainly been getting drenched with those April showers.  Good weather for windscreen wipers though!


Right, enough of the joviality.  Here's a wee dose of Prius statistics to sort you out:

So I've been able to keep the 50.3mpg figure this week.  Would be happier to increase it.  I know, you're probably saying 'take the roof bars off then'.  And you'd be right, of course.  However, being on the cusp of putting our house on the market, I anticipate more runs to the storage centre.  I could take them off (easy enough to do with the Thule roof bars) but I'd have to put them somewhere and since the objective du jour is to keep the house as clutter free as possible this won't happen.  My wife's wrath on one end of the see-saw, an increase in mpg on the other.  You decide.  I know I have.

Okay, that's enough for now.

A bientot,

Sean

Prius MPG Review 18-Apr-2012

Still hitting 50.3mpg - hurray!  My wife has been driving the Prius most of the time over the last week, whilst the task of repairing the rear brakes on our Volvo S40 (having squealed their last squeal) was allocated to me. I did manage to sneak a shot of the Prius on Monday to transport an old pine door to the local paint-stripping shop, but that was all the blissful Prius time I had this week.

Right the stats are back, albeit with a slightly different format.  Table first ... 

	DAY	18
	MONTH	Apr
	Year	2012
	MPG	50.3
	Temp Range (°C)	6 – 12
	Tyre Pressure (psi)	41 psi
	Roof Bars Fitted	Yes
	Roof Box Fitted	No
	Driving Conditions	Mostly extra urban

The chart is in slightly different style, hopefully highlighting the differences in MPG better.

I'll hopefully get the Prius back on Friday since I need to pick up my old pine door.  Perhaps I'll put a post up and show you what the Prius is capable of carrying on its roof.  Until then, TTFN.

Prius MPG Review 11-Apr-2012

I have a smile on my face again - last mpg check on the Prius shows 50.3mpg.  Yes!  We really did encounter some foul weather when down in Galloway on our short easter break recently but the open road and country lanes eem to have agreed with the fully loaded Prius.  I've swapped laptops in the past week so still haven't prepared mpg stats in table or chart format - sorry.  Will definitely get this sorted for next week.  Honest.

You know, the one thing that stuck with me that I found so handy in our trip away was the sun glasses / spectacle holder.  In our Volvo S40, sun glasses and specs are always getting forced into holders and any nook or cranny.  The result is that you forget where you put them or you damage and scratch them.  The Prius sun glasses holder is so easy to use - see the photo below.

You always know where top put your glasses - and where to find them.  And they never get scratched in it.  Excellent.  A little thing, perhaps, but those little things just make life that little bit easier.  Like excellent mpg figures!

Bye 'til next week.

Prius MPG Review 04-Apr-2012

We've gone back over the 50mpg mark!  Hurray! 

Just a quick post today since I am on holiday down on the Galloway coast.  We've done about a third urban and two-thirds extra-urban driving over the past week.    Four people plus holiday luggage in very windy driving conditions were safely and comfortably transported in the Prius from Fife to Galloway - about 180 miles in all.  The mpg has crept back up to 50.2mpg. Bonus.  All other stats remain as before (I'll do charts when I get home for next week's post).

The temperatures have plummeted down from the summer-like numbers of last week down  a minimum of 2°C this week.  We even had snow yesterday!  What is happening to the Scottish climate?  Barking mad.  Anyway, that's all for now.  Speak soon.