Hybrids, not as great as we thought

You mean the one where I first apologised for my lack of delicacy then pointed out that you were talking BS? Okay, will do my best to get to the point...

I was hoping to learn something from you, as you say you _are_ an expert of some kind.

The problem is, on the Net there are numerous people, all to some degree a kook or wanker, who claim to be experts. Commonly, they post under a foolish pseudonym (or maybe meaningless initials). However sensible and reliable folk also do this; but they usually reveal their true identities somewhere along the way. Me, I like to publish under my real name. I try hard to judge others by the postings they produce and the attitudes they adopt. This usually handles the false-name issue. My words speak for themselves. I dislike resorting to claims of qualifications as an argumentative crutch, as you did. If challenged (or if asked politely), I may add info on my qualifications, though mostly it is pointless -- either what I wrote persuades, or it does not. In your case, it does not, so I shall go shed many sad tears and eat worms.

Absolutely. I go around alienating strangers with my unprompted piss-and-vinegar posts out of the blue, I tick off any prat who comes my way... Oh yes, all in all I am a terrible person.

Which quote was that? The quote of my words? You still say that I plagiarised what I wrote about r/b systems? Well, string me up at dawn, podners! You choose not to believe those were my words? Quite frankly, I don't care -- your approval is not worth having, AFAICT. The point of what I've been writing was to entertain and possibly inform whoever else is still following this thread.

Ambiguous question. Let's explore the options:

1) My opinion that you talk BS and are a prat: your postings and my knowledge of engineering (such as it is).

2) My doubts about the accuracy of your engineering opinions: as you insist on knowing: (a) my 2-2 Honours Degree in Electrical Engineering (specialty Light Current but we did power machines in some detail, easily enough for this topic) at London's The City University, graduating in 1969; (b) subsequent professional work in electronic engineering, then programming, then writing on a range of subjects including computing; (c) my ownership of a Mk2 Prius (2005 model) since Aug ust 2005; (d) my general life-long interest in science.

3) My opinion that I really am not interested in wasting longer on you: your first appearance under the pseudonym (c'mon nobody is called _that_) "M.R.S." (which sounds like some kind of brain disease) in this thread, with trollish postings that nevertheless have given me a fine opportunity to indulge in a bit of shameless yet productive Prius advocacy.

Now FOAD. (Merely keeping up my reputation as a Terrible Person, you understand. Nothing personal.)

Reply to
Andrew Stephenson
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graduated in 1969 eh?

You must have excelled in the study of vacuum tubes ;)

You still lack people skills.

Reply to
M.R.S.

Yes, we studied them (as a fading technology) and semiconductors (discrete and integrated: most of the technologies in use today, in fact, because main improvements since then have concerned the fabrication, not the basic ideas), maybe deeper than the average student does today.

Absolutely. In such matters, as in so many, you are the expert and on top of your game. I have not manipulated you at all.

At last -- good grief, I thought you'd never take the hint. Now go and invent a new alias for yourself. Then grow up.

To everyone else: we now resume normal service. Thanks for your patience while the infant was being disciplined...

Reply to
Andrew Stephenson

"M.R.S." wrote: snip

I had understood that if you were 'coasting' then the gear ratio was automatically adjusted so that the motor/generator would provide very little 'drag' (braking) and would be 'geared up' to a higher and higher ratio progressively as the brakes were applied (until, as the vehicle slowed (with the added drag) to some arbitrary point that the system decided that more braking power was needed THEN the brake pads would be applied to provide additional braking..no?...)

Reply to
Gord Beaman

The computer doesn't know when or where you want to stop, so if additional braking is needed it comes from the driver not the "system". Below 10 mph it's almost all driver and no "system". So, if you're not accustomed to driving a Prius, you will either like how the brakes grab at low speed (under 10 miles an hour) or find it alarming. I've witnessed a 50-50 like/did not like response when interested parties drove mine. But those who did not like it said they could get used to it. The other half REALLY liked how the brakes responded.

Originally someone pooh-poohed the idea R/B added anything sufficiently to the brake longevity. All I can say (without getting a headache trying to describe all the possible scenarios) is since the engine "disengages", the R/B feature is more effective, less pedal pressure has to be applied, thus brake wear is minimized.

Don't worry Gordon, we're on the same page. Just think of it as a good classroom discussion without a slouched over pencil wagglin bad boy in the back of the room.

mark_

Reply to
mark_digital

So how much, does that battery cost? And how often replace?

Reply to
windwatcher

I don't know the fine detail. On previous occasions I summarised my understanding of several pages of Toyota manual describing how the Prius implements its braking, a combination of regenerative braking ("r/b") and semi-conventional hydraulics, controlled by the "drive-by-wire" foot brake.

As the hydraulics and friction pads throw energy away (as heat), the system tries to use r/b and recharging of the main battery as much as possible. So I'd expect some clever stuff with gearing, to ensure the generator keeps turning as fast as possible. I am still getting to grips with how the planetary gearing balances loads and inputs from several sources and to several sinks while maintaining the right gearing, so must pass on that bit.

My understanding is that the system is constantly self-adjusting, so the mix of braking mechanisms may vary from moment to moment.

Reply to
Andrew Stephenson

Here we go again. :-) For longer discussions (but beware much fact-free troll-babble), Google for '+prius +"main battery"' in this NG, within the past couple of months. Lots of discussion.

In brief, from my post of 30 March:

Here's a periodic update on the price of the main battery used in the Prius as sold in the UK (and, I suspect, as elsewhere), since this seems to agitate some people. Details supplied today by my local Toyota Centre (sales, service &c), Dingles of Norwich.

Last November, the price (w/o taxes and labour: ie, just battery) was GBP1321.35 (at $1.75/GBP --> $2312.36). It now (30mar2006) is GBP1530.42 ($2678.24).

This 15.8% increase is not surprising, considering how energy and materials prices have rocketed. It seems reasonable to hope that production runs and redesigns will reduce this, either by numbers falling or a static price while inflation boosts everything else. (And I have over seven years of warranty left, so whattheheck.)

Practical lifetime == long. Warranties of 8-10 years, depending on market; but supplier here says they've never had to supply any main batteries. (There is a 12v normal battery for minor jobs.)

Reply to
Andrew Stephenson

regenerative braking ("r/b") and semi-conventional hydraulics, controlled by the "drive-by-wire" foot brake.

do you mean "brake-by-wire"?

Drive by wire relates to throttle... ie: steer by wire... anything X-by-wire

Reply to
Robert Gilroy

The Prius gets referred to a lot as "drive-by-wire", which could well conflict with some people's ideas of what that phrase means. AFAIK, those bits which should remain controllable in the even of servo failures _are_ covered: steering and braking, for example. But everything has servo assistance or some flavour of electronic mediation, save trivia such as lights and lockers. (Oops, sorry, the interior lights have minor funny stuff.) Start/stop, "gear" shift, steering, accelerator and brakes all have assorted amusing clevernesses. Calling it "drive-by-wire" doesn't feel a stretch.

An issue where one probably is free to choose. ;-)

Reply to
Andrew Stephenson

Yes, calling brake-by-wire "drive-by-wire" would be very confusing.

Drive-by-wire refers to throttle control by wire (a unique instance in the Prius, because it doesn't control a typical throttle AFAIK).

X-by-wire refers to any system that uses in-vehicle-networks (CAN, GM-LAN, LIN, J-1839, and Toyota's version).

Brake-by-wire, shift-by-wire, etc..

You've probably heard of Fly-by-wire, which refers to aircraft.

drive-by-wire is just that (speed control).. brake-by-wire refers only to brakes , they are not interchangeable.

more on X-by-wire systems:

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I looked at an '06 Prius today, and I really like it.

Reply to
Robert Gilroy

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