Introducing George

[Arragonis]

Added a tank for the Aygo and the Prius. The Aygo is going positive the Prius is going backwards. This tank was 65 MPG (imp) for the Prius though, which is compared to around 45-46 for the Octavia. We (Mrs A) Will have to work on it to improve.

[Arragonis]

Mildred Update.

We think we have worked out why the last tank for Mildred was not so good. Mrs A was studying the instrumentation provided by the Prius and it has to be said there is a lot to choose from - maybe too much. She was looking at the 1min or 5min MPG interval graphs, especially the regen icons. Basically these are little pictures of cars or half cars (they look like "fat blokes shorts" so they are called "pair of shorts" in our house) which appear whenever you generate 50 Wh of regen energy for the battery. She had worked out that flooring the peddle would allow her to cruise and generate a short or even a full car, some graphs on the 10 min history had the full 7 cars possible - this is her first full tank remember

However we had to look at the MPG aspect. Basically you have to minimise the use of the ICE by allowing the Prius to select the appropriate source. For example we tried going from the end of our road to home (gentle uphill) using only the electric drive, maybe with the EV button which prevents the ICE from being so aggressive. Its about 1/4 of a mile so it should make it but the battery bars go down quickly. However what Mrs A didn't grasp was that the trip out (downhill) would allow the battery to regain at least one of those bars with no ICE - which maximised MPG.

Her strategy of shorts generation meant the ICE is on all or most of the time to provide that speed. Which is great for regen and a full battery but uses fuel to create it. So she needs to change this strategy to minimise ICE use - we shall see. It does mean a change in which "screen" she uses for info.

If I'm honest this is a downside to the Prius - all the info options. Some of them are confusing or perhaps not that much use to an average driver - or maybe also too distracting. It takes a few presses of the display options to get an MPG reading for example, which is really what we want after all. Instant vs average is something I am still trying to find.

This led to me to another thought - is there a market for a simpler hybrid ? A manual gearbox is basically an auto for people who are too cheap to be lazy. So if you had the tech of a Prius but allowed manual control over the sources and when they are used, could this reduce the price of the technology, and make it compact enough for really small cars ? Maybe the Honda IMA system is just that especially in manual cars such as the CR-Z.

Dunno, just a ponder.

[Daox]

The Prius' gearbox is really optimal for engine operation. Since it has full control over engine RPM and power put to the wheels it can first load the engine up to maximize BSFC, after that it increases rpm while still optimally loading the engine to get more power. You can't do that with a manual, at least not to the level of precision that the Prius does.

Also, while driving the Prius at low speeds its actually beneficial to minimize electric usage. Using pulse and glide technique which is quite easy with the Prius will get you the best mileage. You accelerate at a moderate rate and then let off the gas pedal. Immediately push the pedal down just a very small amount and you'll be coasting with the engine off, but also with no electric assist (no arrows pointing anywhere on the display). With this technique its not real hard to hit 100+ mpg at speeds under 40 mph.

Using the electric is just as you said, you get the power ultimately from the gas engine. If you have a huge hill to go down and regen feel free to use electric before that so you can capture that extra energy. But, if you are simply going flat, using the engine is going to be more efficient.

Congrats to both of you though. You're both getting great mileage!

[euromodder]

Originally Posted by Arragonis

She had worked out that flooring the peddle would allow her to cruise and generate a short or even a full car, some graphs on the 10 min history had the full 7 cars possible - this is her first full tank remember

Energy regeneration is trough braking, so it's only recovering some of the energy lost to get you up to speed.
Use it when you need to brake.


It's like coasting vs. engine braking / DFCO.
Even coasting in idle you still win out.


It could be built in to the throttle pedal, by making part of its travel a "neutral zone", and the first part a "regen zone" - but that would make it a non-standard accelerator.
A bit like what Prius users do : get a very light touch of throttle back on so it doesn't go into regen-mode.

[Arragonis]

@Daox - I thought the idea was to use the electric mostly where it is beneficial to do so, low speeds round town and up and down our street being examples ? I don't think (I could be wrong) that floored the Prius looks for the best BSFC point, it assumes you need to go asap. Or at least this one does.

@Both - regen happens on slowing too, its like being in a high gear instead of neutral coasting. You can see the regen part of the eco meter on slowing, it really fills with the braking style regen.

It needs more practice. Motorway (highway / freeway) trips are looking like the trickiest thing to manage.

[Daox]

EV is useful at very low speeds, like in a parking lot. Any normal roads where you are going 25mph/40kph or higher its better to use the engine.

I don't mean to floor it when you accelerate. Without a scangauge its hard to tell, but I accelerate between 2000-2400 rpm. It seems to be a little slower than 'normal' acceleration for most drivers. The BSFC map is pretty broad on the car though so its not hard to keep it in a good area while accelerating.

[Arragonis]

Thanks. One other observation is that the instant MPG graph seems to have only 3 readings. 0, 100 (when moving and the engine is off) and 45 the rest of the time the engine is running. Very little variation from that but that is probably down to driving style.

A couple of other observations whilst I am tapping.

Plus points - ride is very comfortable, handling is pretty good too although we haven't pushed it much. Paint quality is very nice, driving position is flexible enough for both of us to be comfortable driving it. Boot (trunk) size is decent enough, very glad we didn't go for the Auris were this part is all battery.

Noise levels with the engine off is good, the engine can get thrashy if pushed or if it is cold but otherwise well suppressed.

Audio system excellent (according to Junior...), sat-nav works well on some test runs. The rear camera is vital as you have no chance of seeing out the back window.

Bad points - visibility could be better - the little windows at the front are of little use TBH. The interior build quality could also be better - if you are used to VAG products the fit and finish and materials are a little cheap, flashing from the mouldings are visible in some areas, some plastics are very hard. Similarly the rear doors "clang" shut rather than thud and the centre console rattles a bit even though it is empty.

But if that is as bad as it gets then its looking OK.

EDIT - Oh and it has the EV button, did the US one have this missing at one point ?

[Daox]

It was missing from the 1st and 2nd gen Prius in the US. They put it back in for the 3rd gen.

[Arragonis]

Thanks, a 2nd gen with mega miles was an option for me but I thought we would spread our bets a little, and I fancied comparing simple & cheap to hybrid and spendy

[Arragonis]

@Daox - or indeed anyone. When we put Midlred to bed the battery may have all but one bar on it. When we waker her up its down to 1/3 of full. Is that normal ?