First post - remarkable experience and questions.

Hello all,

I am a Prius owner and have been for the last 6 months. My best friend was so impressed with the car that he bought an identical one in a different color.

Both are 2007 advance models.

Over the period of time I have owned the car my consumption has been steadily improving. Each time I fill the car I reset the consumption figure.

When I bought the car the computer read an average of 7.4 litres/100 KLM (previous owner I guess - or test drives). This figure concerned me since I was hoping for 5 litres per 100 KLM.

I realize that US owners won't recognize these figures so for ease the following are the miles per american gallon numbers:

Car at time of purchase : 31.78
Target figure : 47.04

I'll use the US figures from now on.

My first full tank gave me 44.38 - a huge improvement over the figure I started with but from then on things have gone from good to superb to frankly rather unbelievable.

My best average for a full tank is now 65.33 miles per US gallon.

This figure is astonishing to me as I do not really do any of the hypermiling techniques. I never turn the engine off whilst moving - actually I never leave "drive". When going downhill I leave the car in drive to recharge the battery (in other words I never put the car in neutral whilst moving). I do not drive fast (usually) but its not like there is a huge line of cars behind me standing on their horns.

The strange thing is that my BF is not getting these figures even though he drives the same way as me.

Last night we went to a restaurant together with our families and he suggested an economy race home. Whoever could get there burning the least amount of fuel would win although time would be taken into account too.

We both expected that whoever got home first would have the higher consumption but I think we both expected to get home within moments of each other.

The journey was about 9 miles - up and down hills - with innumerable traffic lights. We followed an identical route.

I arrived home 5 minutes before him. I thought he might have stopped off somewhere in fact. When he finally hoved into view and parked we compared consumption (we'd both zeroed the computers).

His car read 57,36
My car read 60,31

In other words although I had been FAR faster I still had better economy. I should mention that the above is the worst figure I have had since August (long trip at high speed with the air-con on the whole way). His figure is the best he has ever had.

He was not pleased so we started to compare cars properly. We discovered a variety of differences - which may mean that one or other of the cars have been modified by a previous owner. Differences are as follows:

1. Driving as gently as possible under electrical power:

My car will reach 71 Klm/hour before the engine cuts in. (sorry - can't be bothered to translate these figures - but you can still see the comparisons).

His car will reach 64 Klm/hour before the engine cuts in.

2. Driving under EV mode:

In EV mode my car will accelerate as hard as you like to 50 Klm.
In EV mode in his car he can only accelerate gently to 45 Klm. If he accelerates hard it automatically switches to the engine.

(Note - the above are obviously subject to having sufficient battery power available. My battery flattens VERY quickly when I do this - especially uphill).

On further note I have not tested my car near the top speed which is quoted as 184 Klm/hour. BF, on the other hand, has a speeding ticket with 191 Klm/hour on it.

So is it possible one or other of the cars have been modified? If so, which one?

 

LOL - it was a first for us too. My previous car was a little less economical than this one - it was a Grand Cherokee (hangs head in shame) that averaged 14.7 miles per gallon.

Of course that was better than the car it replaced (Land Rover Discovery - about 8 mpg).

 

Its certainly true that there are many variables that need to be taken into account - his family is heavier than mine for example, and we are not on the same tyres. With respect to the battery condition at time of setting off his was on Green and mine on Blue so in theory he had the advantage there.

Lots of interesting stuff to ponder upon though - thanks.

Uart,

As regards the use of EV mode I should state that this is something I have only recently started to use. Its also worth bearing in mind that I only use it on routes I know.

Whilst the computer in the car manages the battery excellently there is one area that it will not know as well as I do - which is what lies ahead.

I use the battery according to conditions. This means that often, where I have the opportunity to use the battery I don't - because I am saving it for what lies ahead where using the engine would result in worse overall mileage.

Forcing the engine to use the battery allows to me to get the most out of the combination. I will use it, for example, to pull away from the last lights before a dual carriageway where I expect to be able to cruise at between 70 and 80 Klm/hour for several kilometers. At that speed the engine is running about as efficiently as it can be - and even whilst recharging the battery (actively) it is consuming around 3 litres/100 or over 78 mpg (US).

On any downhill section I take my foot off the gas completely but leave the car in drive so the battery continues to recharge (is this gliding or is that only in neutral?).

By the time I reach the end of the fast section my battery is fully recharged again (from 3 blue bars) and ready to be used for the next congested section.

On the subject of neutral I noticed that if I am going down a slight downhill and I press the accelerator gently there is a point at which the battery is not being charged but there is no power apparently being provided from either the engine or the electric motor. Is this, in effect, neutral whilst in drive?

 

Right - got it and will do. Further questions - Traction Battery? How many batteries are in this car? Is the traction battery the 12V battery or yet another one?

Its amazing this car works reliably when you think about it - its got to be the most complicated car on the road.

 

OK - ignore the traction battery question - found it in the glossary post. Its the main electric battery, right?