Please stop calling them apps!

On Thu, 30 May 2019 23:18:10 +0100, "Commander Kinsey"
wrote:

On Thu, 30 May 2019 22:14:26 +0100, Carlos E.R. wrote:


On 30/05/2019 21.48, Commander Kinsey wrote:
On Thu, 30 May 2019 04:49:38 +0100, Eric Stevens
wrote:

On Wed, 29 May 2019 18:14:05 +0100, "Commander Kinsey"
wrote:


...

For what it is worth, if I am travelling at a
steady 50kph and suddenly plant my foot on the
accelerator, the car will not accelerate
imediately. Certainly the engine revs increase as
the engine speeds up to match 2nd gear at 50kph.
Only when it gets there does the car start to
accelerate.

You must have a really **** car. My autos were 1988, 1998 and
1999. Every one of them accelerated instantly I pressed the
pedal.

Rubbish! No engine has instant acceleration.

Of course it does. As soon as more fuel is available and/or a lower
gear is selected, more power is applied to the wheels.

Right. So you haven't studied applied mechanics. Infinite acceleration
requires infinite force. No engine can go from 1200rpm to 4000rpm
instantaneously.

When did I say it changed instantly to 4000? I said instant
acceleration, which means the car begins speeding up immediately. Of
course this is possible.

That's also what I understand by "instant acceleration". There is
acceleration instantly, and it takes some time to get to the desired
speed. The acceleration can also take some time to grow, maybe
milliseconds for an electric motor. The magnetic fields take time to
build up, the gases take time to burn inside the motor.

The longest time is probably for the engine to increase revs. But that's "instant" when viewing from the speed of the human brain.

You must have a slow brain.
--

Regards,

Eric Stevens

On Thu, 30 May 2019 23:16:00 +0100, "Commander Kinsey"
wrote:

On Thu, 30 May 2019 22:19:34 +0100, Carlos E.R. wrote:

On 30/05/2019 22.57, Commander Kinsey wrote:
On Thu, 30 May 2019 20:24:57 +0100, Carlos E.R.
wrote:

On 29/05/2019 19.14, Commander Kinsey wrote:
On Wed, 29 May 2019 04:15:13 +0100, Eric Stevens
wrote:

On Tue, 28 May 2019 20:50:51 +0100, "Commander Kinsey"
wrote:



For what it is worth, if I am travelling at a steady 50kph and
suddenly plant my foot on the accelerator, the car will not
accelerate
imediately. Certainly the engine revs increase as the engine
speeds up
to match 2nd gear at 50kph. Only when it gets there does the car
start
to accelerate.

You must have a really **** car. My autos were 1988, 1998 and
1999. Every one of them accelerated instantly I pressed the
pedal.

Rubbish! No engine has instant acceleration.

Of course it does. As soon as more fuel is available and/or a lower
gear is selected, more power is applied to the wheels.

Lower gear does not apply more power, it applies more torque. The power
output from the engine is basically the same for the same fuel. If there
is more power, there is more pressure on the accelerator.

Lower gear means higher revs for the same car speed, thus you have more
power from the engine. Higher revs means more fuel burning cycles, so
more power. Think about encountering a steep hill in 5th gear, your car
will not go up it. Select 3rd and it will, because there's more power.

Not really. With my car I have done the experiment, as it has a display
saying the instant amount of fuel it uses per 100 Km. It is traditional
manual shift, as typical here. I change from 5th to 4th while climbing
and the fuel flow is roughly the same.

There is some difference because as the motor turns faster the turbo is
more efficient and the engine should use less fuel at a lower gear...
which is not intuitive.

Surely an engine can burn x amount of fuel per cycle. If you change down to 4th, you're revving higher, so it can take more fuel. If that wasn't true, how do you explain a car being able to climb a hill in 4th that it can't in 5th?

Torque multiplication in the gear box.
--

Regards,

Eric Stevens

On Sat, 01 Jun 2019 00:17:58 +0100, Eric Stevens wrote:

On Thu, 30 May 2019 20:48:53 +0100, "Commander Kinsey"
wrote:

On Thu, 30 May 2019 04:49:38 +0100, Eric Stevens wrote:

On Wed, 29 May 2019 18:14:05 +0100, "Commander Kinsey"
wrote:

On Wed, 29 May 2019 04:15:13 +0100, Eric Stevens wrote:

On Tue, 28 May 2019 20:50:51 +0100, "Commander Kinsey"
wrote:

On Fri, 24 May 2019 11:45:13 +0100, Eric Stevens wrote:

On Thu, 23 May 2019 22:48:34 +0100, "Commander Kinsey"
wrote:

On Thu, 23 May 2019 04:02:58 +0100, Eric Stevens wrote:

On Wed, 22 May 2019 20:32:11 +0100, "Commander Kinsey"
wrote:

On Wed, 22 May 2019 05:56:11 +0100, Eric Stevens wrote:

On Tue, 21 May 2019 22:31:54 +0100, "Commander Kinsey"
wrote:

On Tue, 21 May 2019 22:22:32 +0100, Gene Wirchenko wrote:

On Sun, 19 May 2019 12:33:36 +0100, "Commander Kinsey"
wrote:

[snip]

Are you telling me they now have a two switch mouse with one button over it?
That is monumentally stupid. Imagine if they made a car like that
with one big pedal that accelerated if you touched the right end of it
and braked on the left.

Well, you push (and up) on the left of a steering wheel to go
right and push (and up) on the right of a steering wheel to go left.

I can't believe you think of it like that. I treat it as one wheel which turns the car the way I turn it. Which is why when someone gives me that weird instruction when reversing "left hand down", I say "what the ****? do you want me to go left or right?"

Some gas pedals have a different effect if one floors it at once
versus gradually building up the pressure.

No need for that. All auto cars I've had simply increase power directly proportional to how far I've pushed the pedal down. If that needs a lower gear, it'll select it.

But then, you have told us that the cars you buy all have a relatively
high mileage. If that is the case they will be several years behind
the times.

I'd say the other way round. A car my father had about 40 years ago had "kickdown", presumably because it was badly designed. You actually had to tell it to accelerate harder.

I think you will find that the car had an automatic transmission which
could be made to change down by applying full throttle. In those days
it probably had a three speed aoutomatic transmission.

And nowadays the car can work out when to change down all by itself. And I don't see why it ever couldn't. The more you press the throttle, the more power you want, it really isn't a complicated instruction you're giving it. If the pedal pressure is not going to allow more acceleration in the current, gear, drop a gear.

Even in the days of kick down they could change gear of them selves.

What I don't understand is why they used to have kickdown. Surely all you need to provide is an amount of required acceleration, from zero to full throttle pressure.

Deep sigh ... normally the car is in high gear. If if you put your
foot right down you will get acceleration, but if you were in a lower
gear you would get *more* acceleration. So, how do get into a lower
gear at the moment you put your foot down? In the days we are talking
about you probably had a wiggly stick behind the steering wheel.
Changing gear with this at the same time as you put your foot down is
likely to confuse the hydraulic brains which control the gearbox (even
if you had avoided selecting the wrong gear). So, they provided a
switch under the accelerator pedal to attend to the down change for
you. That was the kick down.

Er, if I want to accelerate a little, I push my foot halfway down. If I want full power I push it all the way down (and therefore expect the lowest gear). I've never had a car which relies on the speed I push the pedal.

Who on earth has said anything about the speed of the pedal push?

That's what kickdown is.

So all this time you have not known what everyone else is talking
about.

Kick down is executed by a switch of some kind which is activated by
the accelerator pedal being pushed right down. It doesn't matter
whether you get there fast or slowly. You have to get there before it
will work.

That's a really **** design. Most cars will drop a gear whenever required, it might be all the way down, it might be 3/4s of the way down. It depends on revs and speed.

For what it is worth, if I am travelling at a steady 50kph and
suddenly plant my foot on the accelerator, the car will not accelerate
imediately. Certainly the engine revs increase as the engine speeds up
to match 2nd gear at 50kph. Only when it gets there does the car start
to accelerate.

You must have a really **** car. My autos were 1988, 1998 and 1999. Every one of them accelerated instantly I pressed the pedal.

Rubbish! No engine has instant acceleration.

Of course it does. As soon as more fuel is available and/or a lower gear is selected, more power is applied to the wheels.

Right. So you haven't studied applied mechanics. Infinite acceleration
requires infinite force. No engine can go from 1200rpm to 4000rpm
instantaneously.

When did I say it changed instantly to 4000? I said instant acceleration, which means the car begins speeding up immediately. Of course this is possible.

You should have said 'started to accelerate' to make your point clear.

Wrong. Immediate acceleration means an increase in speed with no delay, it's really very simple.

But even then, if your operation of th accelerator has caused the
engine to change down a gear or two there will be a delay while the
transmission changes gear(s) and the engine speed rises to match the
new gearing.

As soon as the engine begins rising in speed, the car gets more power. And the delay is so small it's not noticable anyway.

You need that to overtake. Straight away I got the lowest gear possible for that speed, and full throttle to the engine.

You might get it quickly but you don't get it instantaneously.

It was instantaneous enough not to notice it. Why would there be any delay anyway?

So now you are fudging your definition of instantaneous.

I'm being realistic.

You ae being sloppy in your terminology.

And you have OCD, get it fixed by a doctor and embrace reality.

In any case I was describing the same situation. But I have a 3.5L V6
which is quite leisurely at only 50kph. Further a manual change into
low is possible at that speed but 2nd is all that is available in the
automatic range, and that entails a considerable increase in engine
speed which is not instantaneous.

Which is why we have torque converters. You don't just jump from top gear to 2nd.

Are you suggesting the torque converter can maintain drive while the
gearbox is between gears?

Yes. That's precisely what it's for.

You really are a dingbat! The torque convertor merely replaces the
clutch. A torque converter can no more maintain drive when the gearbox
is between gears than can a clutch.

You can (below 40mph) actually drive in 1st and a half. Try this: accelerate gently from a standstill to 40mph. The rev counter will remain at precisely 2000rpm, while the car gradually speeds up. No specific gears, just a gradual change.

The only way you will travel at 40mph at 2000rpm is by being in top
gear. What you have just described is a gentle procession upwards
through the gears with the slip in the torque convertor masking the
gear changes.

It does more than mask it. I doubt you could make a manual gearbox car stay at 2000 revs precisely while you go from 0 to 40mph. Not without damaging the clutch.

But did they change down two gears in the process?

Yes, if required. They were all 4 speed boxes. If I was going at a slow town type speed and put my foot right down, it would drop two gears, maybe even three.

That's unusual. It is uncommon to have an automatic change down to low
unde thos circumstances.

WTF? I would expect any auto car to use the lowest gear possible if I use full throttle. It means I need to move quickly, either to overtake or pull out of a junction into a small gap. Not dropping a gear at that point would be downright dangerous.

What was the car?

VW Golf TDI 1.9 (1998), Honda CRV 2 litre petrol (1999), Range Rover 3.5L V8 (1988).

I have tried to check the owner's manuals. Unfortunately the VW manual
doesn't seem to be available from a site which does not set my
antivirus screaming.

Get a less fussy AV.

Why not turn it off altogether?

I'll rephrase as you're thick. Get a more sensible AV.

The Honda CR-V manual is available on line. It has a 4-speed automatic
transmission. The owners manual says:

"For faster acceleration, you can get the transmission to
automatically downshift by pushing the accelerator pedal to the
floor. The transmission will shift down one or two gears, depending
on your speed."

... so you never get to the lowest gear.

You claimed above that you were surprised you could drop two gears. 3rd to 1st is a drop of 2 gears, which the manual you just read says is possible.

The only time it will drop down two gears is when it changes from 4th
(top) to 2nd.

Thanks for agreeing with me that a 2 gear drop is possible.

On my current car that is the range of gears available
in D. I can if necessary manually select L which is 1st gear but the
engine manager will never select 1st gear once the car is under way.
That is the normal behaviour of most automatic transmissions/

It should select 1st if you put your foot down and 1st is sensible. Say if you're doing 5mph in a queue. 1st should allow up to about 20mph.

I found the Range Rover details at
https://www.ultimatespecs.com/car-sp...-I-35i-v8.html
or http://tinyurl.com/yxz339cs
Your car would have had a ZF 4HP22 automatic transmission. As far as I
can tell, the only time that ever goes into low gear is when the
vehicle is stopped. So kicking down on the move does not get you the
lowest gear.

Since it has 4 gears, 4th to 2nd would have also denied your surprise at "But did they change down two gears in the process?"

That wasn't an expression of surprise. The curly character on the end
of the sentence indicates that it was a question.

It indicated you didn't believe me.

So there I am trundling along at about 1200 rpm and by going to full
throttle I am asking it to go to about 4000 rpm in 2nd gear. What
would you have it do? Slam it straight into 2nd and have the inertia
of the car jerk it up to speed? Or would you delay the engagement of
2nd gear until the engine was up to speed? I know which I would
prefer.

There is no jerk with a torque convertor. And it takes virtually no time to spin an engine up anyway. Try this - sit in your drive with the car in neutral at 1200rpm, stand on the accelerator. Look how quick it gets to full revs.

The torque convertor is not involved in the gear change. It's all done
by clutches inside the gear box.

Of course it's used, it's why you don't feel it changing gear. As you press the throttle a little, the engine revs increase but you stay in the same gear, this is the torque convertor slipping. As you press the throttle more, the car decides to change gear and the torque convertor adjust accordingly.

I certainly feel it changing gear. When I'm changing down there is a
sudden thump in the back as the power goes on.

I'd get that checked if I were you. Clunking auto boxes mean imminent failure.

When did I say anything about a clunking auto gear box?

"Sudden thump in the back". That kinda noise would worry me.

(Incidentally, your sentence has more or less brought us back on
topic.

What?

Please stop calling them auto!).

What other word should be used?

When I'm changing up as
the car accelerates I feel the change in thrust as the gear change. As
I have already said, the gearchange is not done by the torque
convertor. Certainly it may slip under the increased load but at the
higher speeds of fuill acceleration it is probably locked up.

The slippage is what stops the car lurching. That's why there is a torque convertor.

You ae confusing a torque convertor with a fluid flywheel. Torque
convertors have the properties of an infinitely variable automatic
gear box: you can have more torque coming out than you have going in.

Precisely. They allow you to have full power output halfway between gears.

On Fri, 31 May 2019 12:44:09 -0400, Paul
wrote:

Eric Stevens wrote:
On Wed, 29 May 2019 23:13:08 -0400, Paul
wrote:

Not all that GRP/Carbon structure. Not the massive reinforced concrete
base in the ground.
https://www.saskwind.ca/blogbackend/...a-wind-turbine


You are going to see a massive increase in network costs.

A number of the power companies are publicly traded,
and considered in the investment community to be "blue chip".
When they modify the basket mix of energy sources, the
transition has to be managed within the financial limits
of the company.

"Has to be" is not the same as "can be".

Exceptions could happen in the largest hydro projects, where
the investment is as much as for a nuclear reactor. Some of those
projects have "zoomed out of control".

As far as I can see the problem arises from the fact that with both
wind and solar power is being injected into the system from entirely
new locations. When these fluctuate backup power has to very quickly
sourced from wherever the spinning reserve may be. This means that as
the sun appars and disappears behind clouds, or the wind does or
doesn't blow (or blows too hard) a lot of juggling is required to
maintain stability in the system. In many cases this has required
major redesigns of the network to maintain an acceptable level of
stability.

You can see in the Saskatchewan case, they're working incrementally
towards a target. 3% or so wind today. Up to 30% wind at some
point in the future. There must be some plan in place, to
adjust connections to the rest of the network in such a way
as to make that possible. Remember that in each of these power
companies, there are North-South connections for inport-export,
which means "your own basket" does not necessarily contain
all the materials for a solution. There is a good deal
of North-South movement at 8AM local time with these
setups, and opportunities for profit via "spot-pricing".

*******

As for the base design, like everything in life, there are
variations. There are methods available (pile driving) which
cause the amount of materials in the base to be reduced. These
will not work in all locations.

http://www.geoteknik.lth.se/fileadmi...00/web5173.pdf

To give an example, when I moved to this city at the beginning
of my career, there was an apartment building going up across from
mine. My apartment building was 20 stories or so, and on the top
of a hill.

When I was talking to someone about the new apartment, he said:

"You know, we're on top of a giant sand dune".

I thought he was joking. He was not.

What happened next, was quite amazing. Heavy machinery showed up.
They started driving piles. The piles were extended (some sort
of screw-together pieces. The piles must have gone down 100ft to 120ft
each. There could have been 30 or 40 of these piles. And this
was how an apartment building was going to be anchored to a
"sand dune" :-)

There were no signs of problems with this. The area is subject
to earthquakes up to 5 on the Richter scale. The earthquake
that was a "5", was perfectly vertical, and the apartment
building with the piles would not be challenged by that one.
No objects free-standing (on mantle piece) got knocked
over by that one, as my house was "picked up... and dropped"
with a resounding "crack" noise. We've had lesser earthquakes
with more horizontal motions.

I could see how various kinds of steel piles could
be used for "difficult" geotechnical conditions. And then
the base doesn't have to waste quite as much material.

Paul
--

Regards,

Eric Stevens

On Fri, 31 May 2019 15:30:13 -0000 (UTC), Roger Blake
wrote:

On 2019-05-31, Eric Stevens wrote:
It was a while ago and if I could have found a link I would already
have given it to you. In anycase, the nett liftime CO2 depends upon
the network in which the wind generators are being used.

The net lifetime of CO2 is irrelevant because CO2 is not a pollutant.

I entirely agree. But it is a subject of discussion and in this
general case it is considered very illogically.

The "global warming/climate change" scam has nothing to do with the
environment. It's about greedy governments and elites grabbing even more
power and money for themselves and making fundamental changes in society
using the manufactured excuse of "saving the planet". For the rank and
file "climate change" useful idiots it is a religion.

The Faithful continue to drink the kool-aid even when those involved
in pushing the scam admit what they are doing. You'll have an easier
time convincing an evangelical Christian of Biblical errancy than
getting a Climate Cultist to recognize that they've being played.

https://www.investors.com/politics/e...oy-capitalism/

For myself I will not do a thing to lower my so-called "carbon footprint".
--

Regards,

Eric Stevens

On 31 May 2019 17:17:01 GMT, "John Varela"
wrote:

On Fri, 31 May 2019 15:30:13 UTC, Roger Blake
wrote:

On 2019-05-31, Eric Stevens wrote:
It was a while ago and if I could have found a link I would already
have given it to you. In anycase, the nett liftime CO2 depends upon
the network in which the wind generators are being used.

The net lifetime of CO2 is irrelevant because CO2 is not a pollutant.

The "global warming/climate change" scam has nothing to do with the
environment. It's about greedy governments and elites grabbing even more
power and money for themselves and making fundamental changes in society
using the manufactured excuse of "saving the planet". For the rank and
file "climate change" useful idiots it is a religion.

The Faithful continue to drink the kool-aid even when those involved
in pushing the scam admit what they are doing. You'll have an easier
time convincing an evangelical Christian of Biblical errancy than
getting a Climate Cultist to recognize that they've being played.

https://www.investors.com/politics/e...oy-capitalism/

For myself I will not do a thing to lower my so-called "carbon footprint".

Well there's invincible ignorance for you.

Not in my case. I started off as a believer and I've been following
the science for thirty years. Now I don't know a part of the IPCC and
UN warming theory which will withstand close examination. The test is
in the model outputs which are completely out of touch with reality.
--

Regards,

Eric Stevens

On Fri, 31 May 2019 17:39:22 -0000 (UTC), Chris
wrote:

Eric Stevens wrote:
On Thu, 30 May 2019 21:18:58 +0200, "Carlos E.R."
wrote:

On 30/05/2019 03.00, Eric Stevens wrote:
On Wed, 29 May 2019 10:46:29 -0000 (UTC), Chris
wrote:

Eric Stevens wrote:
On Wed, 29 May 2019 09:20:16 -0000 (UTC), Chris
wrote:

Eric Stevens wrote:
On Tue, 28 May 2019 22:07:20 -0000 (UTC), Chris
wrote:

Eric Stevens wrote:
On Sun, 26 May 2019 14:22:42 -0000 (UTC), Chris
wrote:

Mark Lloyd wrote:
On 5/24/19 5:36 PM, Peter Jason wrote:


anyone buying an electric vehicle would likely upgrade their garage
wiring.

Why bother. A petrol engine is cheaper to buy & run, has proven
technology, and a longer range by far.

Where are they getting the fuel to generate all the electricity for
electric cars. Coal? Nuclear?

They claim that the generating plants are much more efficient than car
engines. I don't know if that's true or not.

Electric cars allow the use of renewable energy sources (solar, wind,
hydro, etc) thereby reducing carbon emissions, plus reduce pollution in
cities.

Yes. Charging your car overnight with the solar power cells on the
roof of your house makes particular sense.

Snark noted. There are other forms of renewable energy that work in the
dark. Also cars are charged at all times of the day. You may have noticed
that cars spend most of the time parked.

Are you aware that wind power requires that a usually fuel burning
power plant remains on line to keep it backed up through wind
fluctuations? That doesn't make it cheaper or reduce carbon emissions.

Of course it does. Uk carbon intensity has dropped 17% since 2016.
http://www.mygridgb.co.uk/last-12-months/

Its only cheaper if you dont count the cost of maintaining a spinning
reserve.

Nope. There's always been a spinning reserve to cope with sudden surges.
Renewables don't change that. There's always going to be mix as each type
of generator has pros and cons. Nuclear is cheap, but slow; hydro is very
fast, but limited; renewables are very cheap, but unreliable.

Both solar and wind have a highre demand on spinning reserve than just
about anything else.

So what. The net result is still a reduction in CO2 emissions per unit of
energy generated. That is what's relevant and important.

Its marginal. Some calculations of lifetime carbon suggest that wind
generators in particular generate more CO2 over their lifetime than is
saved by their use.

What about the energy needed to build the coal or gas generators?

Assuming its a steam plant experience shows that the lifetime is about
40 years. Likewise, experience is now showing that the average life
expectancy of wind generators is about 10 years. That tends to
equalize the amortizing of the initial input.

The cost of building and commissioning a large generator is way more than
4x wind generators.

But they don't need additional spinning reserve or complications in
the network to maintain stability.
--

Regards,

Eric Stevens

On Sat, 01 Jun 2019 00:27:05 +0100, "Commander Kinsey"
wrote:

On Sat, 01 Jun 2019 00:17:58 +0100, Eric Stevens wrote:

On Thu, 30 May 2019 20:48:53 +0100, "Commander Kinsey"
wrote:

On Thu, 30 May 2019 04:49:38 +0100, Eric Stevens wrote:

On Wed, 29 May 2019 18:14:05 +0100, "Commander Kinsey"
wrote:

On Wed, 29 May 2019 04:15:13 +0100, Eric Stevens wrote:

On Tue, 28 May 2019 20:50:51 +0100, "Commander Kinsey"
wrote:

On Fri, 24 May 2019 11:45:13 +0100, Eric Stevens wrote:

On Thu, 23 May 2019 22:48:34 +0100, "Commander Kinsey"
wrote:

On Thu, 23 May 2019 04:02:58 +0100, Eric Stevens wrote:

On Wed, 22 May 2019 20:32:11 +0100, "Commander Kinsey"
wrote:

On Wed, 22 May 2019 05:56:11 +0100, Eric Stevens wrote:

On Tue, 21 May 2019 22:31:54 +0100, "Commander Kinsey"
wrote:

On Tue, 21 May 2019 22:22:32 +0100, Gene Wirchenko wrote:

On Sun, 19 May 2019 12:33:36 +0100, "Commander Kinsey"
wrote:

[snip]

Are you telling me they now have a two switch mouse with one button over it?
That is monumentally stupid. Imagine if they made a car like that
with one big pedal that accelerated if you touched the right end of it
and braked on the left.

Well, you push (and up) on the left of a steering wheel to go
right and push (and up) on the right of a steering wheel to go left.

I can't believe you think of it like that. I treat it as one wheel which turns the car the way I turn it. Which is why when someone gives me that weird instruction when reversing "left hand down", I say "what the ****? do you want me to go left or right?"

Some gas pedals have a different effect if one floors it at once
versus gradually building up the pressure.

No need for that. All auto cars I've had simply increase power directly proportional to how far I've pushed the pedal down. If that needs a lower gear, it'll select it.

But then, you have told us that the cars you buy all have a relatively
high mileage. If that is the case they will be several years behind
the times.

I'd say the other way round. A car my father had about 40 years ago had "kickdown", presumably because it was badly designed. You actually had to tell it to accelerate harder.

I think you will find that the car had an automatic transmission which
could be made to change down by applying full throttle. In those days
it probably had a three speed aoutomatic transmission.

And nowadays the car can work out when to change down all by itself. And I don't see why it ever couldn't. The more you press the throttle, the more power you want, it really isn't a complicated instruction you're giving it. If the pedal pressure is not going to allow more acceleration in the current, gear, drop a gear.

Even in the days of kick down they could change gear of them selves.

What I don't understand is why they used to have kickdown. Surely all you need to provide is an amount of required acceleration, from zero to full throttle pressure.

Deep sigh ... normally the car is in high gear. If if you put your
foot right down you will get acceleration, but if you were in a lower
gear you would get *more* acceleration. So, how do get into a lower
gear at the moment you put your foot down? In the days we are talking
about you probably had a wiggly stick behind the steering wheel.
Changing gear with this at the same time as you put your foot down is
likely to confuse the hydraulic brains which control the gearbox (even
if you had avoided selecting the wrong gear). So, they provided a
switch under the accelerator pedal to attend to the down change for
you. That was the kick down.

Er, if I want to accelerate a little, I push my foot halfway down. If I want full power I push it all the way down (and therefore expect the lowest gear). I've never had a car which relies on the speed I push the pedal.

Who on earth has said anything about the speed of the pedal push?

That's what kickdown is.

So all this time you have not known what everyone else is talking
about.

Kick down is executed by a switch of some kind which is activated by
the accelerator pedal being pushed right down. It doesn't matter
whether you get there fast or slowly. You have to get there before it
will work.

That's a really **** design. Most cars will drop a gear whenever required, it might be all the way down, it might be 3/4s of the way down. It depends on revs and speed.

Once again you have demonstrated that you do not relly understand what
you are talking about. The automatic transmission is always controlled
so as to select the appropriate gear for the throttle opening, the
engine speed and the speed of the car. This may mean that it will
change down a gear even when you are only at part throttle. But if you
want everything you can get *right now* you floor the accelerator and
kickdown bypasses the transmission controller and selects the lowest
gear available at the speed. It's not a such big difference now but it
was most significant in the days of wide-ratio 3-speed automatic
transmissions.

For what it is worth, if I am travelling at a steady 50kph and
suddenly plant my foot on the accelerator, the car will not accelerate
imediately. Certainly the engine revs increase as the engine speeds up
to match 2nd gear at 50kph. Only when it gets there does the car start
to accelerate.

You must have a really **** car. My autos were 1988, 1998 and 1999. Every one of them accelerated instantly I pressed the pedal.

Rubbish! No engine has instant acceleration.

Of course it does. As soon as more fuel is available and/or a lower gear is selected, more power is applied to the wheels.

Right. So you haven't studied applied mechanics. Infinite acceleration
requires infinite force. No engine can go from 1200rpm to 4000rpm
instantaneously.

When did I say it changed instantly to 4000? I said instant acceleration, which means the car begins speeding up immediately. Of course this is possible.

You should have said 'started to accelerate' to make your point clear.

Wrong. Immediate acceleration means an increase in speed with no delay, it's really very simple.

Don't forget we are discussing a kickdown. Full acceleration (the
state which the driver is trying to achieve) is not available
instantaneously.

But even then, if your operation of th accelerator has caused the
engine to change down a gear or two there will be a delay while the
transmission changes gear(s) and the engine speed rises to match the
new gearing.

As soon as the engine begins rising in speed, the car gets more power. And the delay is so small it's not noticable anyway.

Not while the transmission is in the process of changing gears and it
is rtue that the insensitive may not be aware of the delay.

You need that to overtake. Straight away I got the lowest gear possible for that speed, and full throttle to the engine.

You might get it quickly but you don't get it instantaneously.

It was instantaneous enough not to notice it. Why would there be any delay anyway?

So now you are fudging your definition of instantaneous.

I'm being realistic.

You ae being sloppy in your terminology.

And you have OCD, get it fixed by a doctor and embrace reality.

In any case I was describing the same situation. But I have a 3.5L V6
which is quite leisurely at only 50kph. Further a manual change into
low is possible at that speed but 2nd is all that is available in the
automatic range, and that entails a considerable increase in engine
speed which is not instantaneous.

Which is why we have torque converters. You don't just jump from top gear to 2nd.

Are you suggesting the torque converter can maintain drive while the
gearbox is between gears?

Yes. That's precisely what it's for.

You really are a dingbat! The torque convertor merely replaces the
clutch. A torque converter can no more maintain drive when the gearbox
is between gears than can a clutch.

You can (below 40mph) actually drive in 1st and a half. Try this: accelerate gently from a standstill to 40mph. The rev counter will remain at precisely 2000rpm, while the car gradually speeds up. No specific gears, just a gradual change.

The only way you will travel at 40mph at 2000rpm is by being in top
gear. What you have just described is a gentle procession upwards
through the gears with the slip in the torque convertor masking the
gear changes.

It does more than mask it. I doubt you could make a manual gearbox car stay at 2000 revs precisely while you go from 0 to 40mph. Not without damaging the clutch.

Your logic is impenatrable.

But did they change down two gears in the process?

Yes, if required. They were all 4 speed boxes. If I was going at a slow town type speed and put my foot right down, it would drop two gears, maybe even three.

That's unusual. It is uncommon to have an automatic change down to low
unde thos circumstances.

WTF? I would expect any auto car to use the lowest gear possible if I use full throttle. It means I need to move quickly, either to overtake or pull out of a junction into a small gap. Not dropping a gear at that point would be downright dangerous.

What was the car?

VW Golf TDI 1.9 (1998), Honda CRV 2 litre petrol (1999), Range Rover 3.5L V8 (1988).

I have tried to check the owner's manuals. Unfortunately the VW manual
doesn't seem to be available from a site which does not set my
antivirus screaming.

Get a less fussy AV.

Why not turn it off altogether?

I'll rephrase as you're thick. Get a more sensible AV.

And what %age of the plague would you like today sir?

The Honda CR-V manual is available on line. It has a 4-speed automatic
transmission. The owners manual says:

"For faster acceleration, you can get the transmission to
automatically downshift by pushing the accelerator pedal to the
floor. The transmission will shift down one or two gears, depending
on your speed."

... so you never get to the lowest gear.

You claimed above that you were surprised you could drop two gears. 3rd to 1st is a drop of 2 gears, which the manual you just read says is possible.

The only time it will drop down two gears is when it changes from 4th
(top) to 2nd.

Thanks for agreeing with me that a 2 gear drop is possible.

Did I ever say otherwise? What I have said is that you will not get a
2 gear drop if it is going to take you into low.

On my current car that is the range of gears available
in D. I can if necessary manually select L which is 1st gear but the
engine manager will never select 1st gear once the car is under way.
That is the normal behaviour of most automatic transmissions/

It should select 1st if you put your foot down and 1st is sensible. Say if you're doing 5mph in a queue. 1st should allow up to about 20mph.

But they don't usually work that way.

I found the Range Rover details at
https://www.ultimatespecs.com/car-sp...-I-35i-v8.html
or http://tinyurl.com/yxz339cs
Your car would have had a ZF 4HP22 automatic transmission. As far as I
can tell, the only time that ever goes into low gear is when the
vehicle is stopped. So kicking down on the move does not get you the
lowest gear.

Since it has 4 gears, 4th to 2nd would have also denied your surprise at "But did they change down two gears in the process?"

That wasn't an expression of surprise. The curly character on the end
of the sentence indicates that it was a question.

It indicated you didn't believe me.

It couldn't mean that. You hadn't said anything about gear changes. It
was a genuine enquiry.

So there I am trundling along at about 1200 rpm and by going to full
throttle I am asking it to go to about 4000 rpm in 2nd gear. What
would you have it do? Slam it straight into 2nd and have the inertia
of the car jerk it up to speed? Or would you delay the engagement of
2nd gear until the engine was up to speed? I know which I would
prefer.

There is no jerk with a torque convertor. And it takes virtually no time to spin an engine up anyway. Try this - sit in your drive with the car in neutral at 1200rpm, stand on the accelerator. Look how quick it gets to full revs.

The torque convertor is not involved in the gear change. It's all done
by clutches inside the gear box.

Of course it's used, it's why you don't feel it changing gear. As you press the throttle a little, the engine revs increase but you stay in the same gear, this is the torque convertor slipping. As you press the throttle more, the car decides to change gear and the torque convertor adjust accordingly.

I certainly feel it changing gear. When I'm changing down there is a
sudden thump in the back as the power goes on.

I'd get that checked if I were you. Clunking auto boxes mean imminent failure.

When did I say anything about a clunking auto gear box?

"Sudden thump in the back". That kinda noise would worry me.

I mean the onset of acceleration - push in the back sensation.

(Incidentally, your sentence has more or less brought us back on
topic.

What?

Please stop calling them auto!).

What other word should be used?

I am sure you will find one if you app yourself to a dic.

When I'm changing up as
the car accelerates I feel the change in thrust as the gear change. As
I have already said, the gearchange is not done by the torque
convertor. Certainly it may slip under the increased load but at the
higher speeds of fuill acceleration it is probably locked up.

The slippage is what stops the car lurching. That's why there is a torque convertor.

You ae confusing a torque convertor with a fluid flywheel. Torque
convertors have the properties of an infinitely variable automatic
gear box: you can have more torque coming out than you have going in.

Precisely. They allow you to have full power output halfway between gears.

Do you really think that power can be transmitted to the wheels in
those instants when no gear is engaged?
--

Regards,

Eric Stevens

On 5/31/19 11:18 AM, Commander Kinsey wrote:
On Fri, 31 May 2019 16:50:27 +0100, Mark Lloyd wrote:

On 5/30/19 2:07 PM, Jonathan N. Little wrote:
Commander Kinsey wrote:
Which makes perfect sense, when your car moves, it's because you've
engaged the clutch, not killed it.

Actually if you *engage* the clutch you will *not* move, you have to
*disengage* a clutch in order to link engine output shaft to drive
shaft. Been driving a standard transmission for over 45 years...

That sounds like the words are being used backward. Engaging is
connecting (engine output to drive shaft).

More like people getting mixed up because you press the pedal to
disengage it.* People assume pushing the pedal will engage it.

That could explain what happened, people considering the "engagement"
between foot and pedal, rather than in the clutch itself. I thought of
the clutch.

--
Mark Lloyd
http://notstupid.us/

"Over and above that we let them get rich on our sweat and blood, while
we remain poor and they such the marrow from our bones. [Martin
Luther,"On the Jews and Their Lies",1543]

On 5/31/19 5:53 PM, Commander Kinsey wrote:

[snip]

That's because they speak legalese and not English, they live in the
last century.* At least.

I remember when I looked at a will and saw the word "decedent"
(DEE-CEE-DENT). It took awhile to notice that the word was NOT
"decadent" (DECK-UH-DUNT).

--
Mark Lloyd
http://notstupid.us/

"Over and above that we let them get rich on our sweat and blood, while
we remain poor and they such the marrow from our bones. [Martin
Luther,"On the Jews and Their Lies",1543]

On Sat, 01 Jun 2019 14:06:52 +0100, Mark Lloyd wrote:

On 5/31/19 5:53 PM, Commander Kinsey wrote:

[snip]

That's because they speak legalese and not English, they live in the
last century. At least.

I remember when I looked at a will and saw the word "decedent"
(DEE-CEE-DENT). It took awhile to notice that the word was NOT
"decadent" (DECK-UH-DUNT).

Indeed, they either make words up or use ones that were taken from common usage 100s of years ago.

On Sat, 01 Jun 2019 13:59:31 +0100, Mark Lloyd wrote:

On 5/31/19 11:18 AM, Commander Kinsey wrote:
On Fri, 31 May 2019 16:50:27 +0100, Mark Lloyd wrote:

On 5/30/19 2:07 PM, Jonathan N. Little wrote:
Commander Kinsey wrote:
Which makes perfect sense, when your car moves, it's because you've
engaged the clutch, not killed it.

Actually if you *engage* the clutch you will *not* move, you have to
*disengage* a clutch in order to link engine output shaft to drive
shaft. Been driving a standard transmission for over 45 years...

That sounds like the words are being used backward. Engaging is
connecting (engine output to drive shaft).

More like people getting mixed up because you press the pedal to
disengage it. People assume pushing the pedal will engage it.

That could explain what happened, people considering the "engagement"
between foot and pedal, rather than in the clutch itself. I thought of
the clutch.

Some people aren't too bright. Obviously a device which stops the engine powering the wheels when you press the pedal must have been disengaged.

On Sat, 01 Jun 2019 00:20:49 +0100, Eric Stevens wrote:

On Thu, 30 May 2019 23:16:00 +0100, "Commander Kinsey"
wrote:

On Thu, 30 May 2019 22:19:34 +0100, Carlos E.R. wrote:

On 30/05/2019 22.57, Commander Kinsey wrote:
On Thu, 30 May 2019 20:24:57 +0100, Carlos E.R.
wrote:

On 29/05/2019 19.14, Commander Kinsey wrote:
On Wed, 29 May 2019 04:15:13 +0100, Eric Stevens
wrote:

On Tue, 28 May 2019 20:50:51 +0100, "Commander Kinsey"
wrote:



For what it is worth, if I am travelling at a steady 50kph and
suddenly plant my foot on the accelerator, the car will not
accelerate
imediately. Certainly the engine revs increase as the engine
speeds up
to match 2nd gear at 50kph. Only when it gets there does the car
start
to accelerate.

You must have a really **** car. My autos were 1988, 1998 and
1999. Every one of them accelerated instantly I pressed the
pedal.

Rubbish! No engine has instant acceleration.

Of course it does. As soon as more fuel is available and/or a lower
gear is selected, more power is applied to the wheels.

Lower gear does not apply more power, it applies more torque. The power
output from the engine is basically the same for the same fuel. If there
is more power, there is more pressure on the accelerator.

Lower gear means higher revs for the same car speed, thus you have more
power from the engine. Higher revs means more fuel burning cycles, so
more power. Think about encountering a steep hill in 5th gear, your car
will not go up it. Select 3rd and it will, because there's more power.

Not really. With my car I have done the experiment, as it has a display
saying the instant amount of fuel it uses per 100 Km. It is traditional
manual shift, as typical here. I change from 5th to 4th while climbing
and the fuel flow is roughly the same.

There is some difference because as the motor turns faster the turbo is
more efficient and the engine should use less fuel at a lower gear...
which is not intuitive.

Surely an engine can burn x amount of fuel per cycle. If you change down to 4th, you're revving higher, so it can take more fuel. If that wasn't true, how do you explain a car being able to climb a hill in 4th that it can't in 5th?

Torque multiplication in the gear box.

The main thing is how much power is the engine outputting. If that's less than the potential energy required to lift the car up the hill, it will not proceed. Lowering the gear lets the engine spin faster, so it can output a greater power.

On Sat, 01 Jun 2019 00:18:56 +0100, Eric Stevens wrote:

On Thu, 30 May 2019 23:18:10 +0100, "Commander Kinsey"
wrote:

On Thu, 30 May 2019 22:14:26 +0100, Carlos E.R. wrote:


On 30/05/2019 21.48, Commander Kinsey wrote:
On Thu, 30 May 2019 04:49:38 +0100, Eric Stevens
wrote:

On Wed, 29 May 2019 18:14:05 +0100, "Commander Kinsey"
wrote:


...

For what it is worth, if I am travelling at a
steady 50kph and suddenly plant my foot on the
accelerator, the car will not accelerate
imediately. Certainly the engine revs increase as
the engine speeds up to match 2nd gear at 50kph.
Only when it gets there does the car start to
accelerate.

You must have a really **** car. My autos were 1988, 1998 and
1999. Every one of them accelerated instantly I pressed the
pedal.

Rubbish! No engine has instant acceleration.

Of course it does. As soon as more fuel is available and/or a lower
gear is selected, more power is applied to the wheels.

Right. So you haven't studied applied mechanics. Infinite acceleration
requires infinite force. No engine can go from 1200rpm to 4000rpm
instantaneously.

When did I say it changed instantly to 4000? I said instant
acceleration, which means the car begins speeding up immediately. Of
course this is possible.

That's also what I understand by "instant acceleration". There is
acceleration instantly, and it takes some time to get to the desired
speed. The acceleration can also take some time to grow, maybe
milliseconds for an electric motor. The magnetic fields take time to
build up, the gases take time to burn inside the motor.

The longest time is probably for the engine to increase revs. But that's "instant" when viewing from the speed of the human brain.

You must have a slow brain.

If your brain works faster than that, you must desire to drive at 250mph through city centres.

On Sat, 01 Jun 2019 03:09:40 +0100, Eric Stevens wrote:

On Sat, 01 Jun 2019 00:27:05 +0100, "Commander Kinsey"
wrote:

On Sat, 01 Jun 2019 00:17:58 +0100, Eric Stevens wrote:

On Thu, 30 May 2019 20:48:53 +0100, "Commander Kinsey"
wrote:

On Thu, 30 May 2019 04:49:38 +0100, Eric Stevens wrote:

On Wed, 29 May 2019 18:14:05 +0100, "Commander Kinsey"
wrote:

On Wed, 29 May 2019 04:15:13 +0100, Eric Stevens wrote:

On Tue, 28 May 2019 20:50:51 +0100, "Commander Kinsey"
wrote:

On Fri, 24 May 2019 11:45:13 +0100, Eric Stevens wrote:

On Thu, 23 May 2019 22:48:34 +0100, "Commander Kinsey"
wrote:

On Thu, 23 May 2019 04:02:58 +0100, Eric Stevens wrote:

On Wed, 22 May 2019 20:32:11 +0100, "Commander Kinsey"
wrote:

On Wed, 22 May 2019 05:56:11 +0100, Eric Stevens wrote:

On Tue, 21 May 2019 22:31:54 +0100, "Commander Kinsey"
wrote:

On Tue, 21 May 2019 22:22:32 +0100, Gene Wirchenko wrote:

On Sun, 19 May 2019 12:33:36 +0100, "Commander Kinsey"
wrote:

[snip]

Are you telling me they now have a two switch mouse with one button over it?
That is monumentally stupid. Imagine if they made a car like that
with one big pedal that accelerated if you touched the right end of it
and braked on the left.

Well, you push (and up) on the left of a steering wheel to go
right and push (and up) on the right of a steering wheel to go left.

I can't believe you think of it like that. I treat it as one wheel which turns the car the way I turn it. Which is why when someone gives me that weird instruction when reversing "left hand down", I say "what the ****? do you want me to go left or right?"

Some gas pedals have a different effect if one floors it at once
versus gradually building up the pressure.

No need for that. All auto cars I've had simply increase power directly proportional to how far I've pushed the pedal down. If that needs a lower gear, it'll select it.

But then, you have told us that the cars you buy all have a relatively
high mileage. If that is the case they will be several years behind
the times.

I'd say the other way round. A car my father had about 40 years ago had "kickdown", presumably because it was badly designed. You actually had to tell it to accelerate harder.

I think you will find that the car had an automatic transmission which
could be made to change down by applying full throttle. In those days
it probably had a three speed aoutomatic transmission.

And nowadays the car can work out when to change down all by itself. And I don't see why it ever couldn't. The more you press the throttle, the more power you want, it really isn't a complicated instruction you're giving it. If the pedal pressure is not going to allow more acceleration in the current, gear, drop a gear.

Even in the days of kick down they could change gear of them selves.

What I don't understand is why they used to have kickdown. Surely all you need to provide is an amount of required acceleration, from zero to full throttle pressure.

Deep sigh ... normally the car is in high gear. If if you put your
foot right down you will get acceleration, but if you were in a lower
gear you would get *more* acceleration. So, how do get into a lower
gear at the moment you put your foot down? In the days we are talking
about you probably had a wiggly stick behind the steering wheel.
Changing gear with this at the same time as you put your foot down is
likely to confuse the hydraulic brains which control the gearbox (even
if you had avoided selecting the wrong gear). So, they provided a
switch under the accelerator pedal to attend to the down change for
you. That was the kick down.

Er, if I want to accelerate a little, I push my foot halfway down. If I want full power I push it all the way down (and therefore expect the lowest gear). I've never had a car which relies on the speed I push the pedal.

Who on earth has said anything about the speed of the pedal push?

That's what kickdown is.

So all this time you have not known what everyone else is talking
about.

Kick down is executed by a switch of some kind which is activated by
the accelerator pedal being pushed right down. It doesn't matter
whether you get there fast or slowly. You have to get there before it
will work.

That's a really **** design. Most cars will drop a gear whenever required, it might be all the way down, it might be 3/4s of the way down. It depends on revs and speed.

Once again you have demonstrated that you do not relly understand what
you are talking about. The automatic transmission is always controlled
so as to select the appropriate gear for the throttle opening, the
engine speed and the speed of the car. This may mean that it will
change down a gear even when you are only at part throttle.

Exactly what I just said.

But if you
want everything you can get *right now* you floor the accelerator and
kickdown bypasses the transmission controller and selects the lowest
gear available at the speed. It's not a such big difference now but it
was most significant in the days of wide-ratio 3-speed automatic
transmissions.

This means nothing. If you push it 3/4s of the way down you want almost everything you can get, there is no reason for a sudden change at full pressure of the pedal.

For what it is worth, if I am travelling at a steady 50kph and
suddenly plant my foot on the accelerator, the car will not accelerate
imediately. Certainly the engine revs increase as the engine speeds up
to match 2nd gear at 50kph. Only when it gets there does the car start
to accelerate.

You must have a really **** car. My autos were 1988, 1998 and 1999. Every one of them accelerated instantly I pressed the pedal.

Rubbish! No engine has instant acceleration.

Of course it does. As soon as more fuel is available and/or a lower gear is selected, more power is applied to the wheels.

Right. So you haven't studied applied mechanics. Infinite acceleration
requires infinite force. No engine can go from 1200rpm to 4000rpm
instantaneously.

When did I say it changed instantly to 4000? I said instant acceleration, which means the car begins speeding up immediately. Of course this is possible.

You should have said 'started to accelerate' to make your point clear.

Wrong. Immediate acceleration means an increase in speed with no delay, it's really very simple.

Don't forget we are discussing a kickdown. Full acceleration (the
state which the driver is trying to achieve) is not available
instantaneously.

Of course it is. Full acceleration means "as much as the engine can give".

But even then, if your operation of th accelerator has caused the
engine to change down a gear or two there will be a delay while the
transmission changes gear(s) and the engine speed rises to match the
new gearing.

As soon as the engine begins rising in speed, the car gets more power. And the delay is so small it's not noticable anyway.

Not while the transmission is in the process of changing gears and it
is rtue that the insensitive may not be aware of the delay.

Auto boxes change gear pretty damn fast.

You need that to overtake. Straight away I got the lowest gear possible for that speed, and full throttle to the engine.

You might get it quickly but you don't get it instantaneously.

It was instantaneous enough not to notice it. Why would there be any delay anyway?

So now you are fudging your definition of instantaneous.

I'm being realistic.

You ae being sloppy in your terminology.

And you have OCD, get it fixed by a doctor and embrace reality.

In any case I was describing the same situation. But I have a 3.5L V6
which is quite leisurely at only 50kph. Further a manual change into
low is possible at that speed but 2nd is all that is available in the
automatic range, and that entails a considerable increase in engine
speed which is not instantaneous.

Which is why we have torque converters. You don't just jump from top gear to 2nd.

Are you suggesting the torque converter can maintain drive while the
gearbox is between gears?

Yes. That's precisely what it's for.

You really are a dingbat! The torque convertor merely replaces the
clutch. A torque converter can no more maintain drive when the gearbox
is between gears than can a clutch.

You can (below 40mph) actually drive in 1st and a half. Try this: accelerate gently from a standstill to 40mph. The rev counter will remain at precisely 2000rpm, while the car gradually speeds up. No specific gears, just a gradual change.

The only way you will travel at 40mph at 2000rpm is by being in top
gear. What you have just described is a gentle procession upwards
through the gears with the slip in the torque convertor masking the
gear changes.

It does more than mask it. I doubt you could make a manual gearbox car stay at 2000 revs precisely while you go from 0 to 40mph. Not without damaging the clutch.

Your logic is impenatrable.

So you agree with me then.

But did they change down two gears in the process?

Yes, if required. They were all 4 speed boxes. If I was going at a slow town type speed and put my foot right down, it would drop two gears, maybe even three.

That's unusual. It is uncommon to have an automatic change down to low
unde thos circumstances.

WTF? I would expect any auto car to use the lowest gear possible if I use full throttle. It means I need to move quickly, either to overtake or pull out of a junction into a small gap. Not dropping a gear at that point would be downright dangerous.

What was the car?

VW Golf TDI 1.9 (1998), Honda CRV 2 litre petrol (1999), Range Rover 3.5L V8 (1988).

I have tried to check the owner's manuals. Unfortunately the VW manual
doesn't seem to be available from a site which does not set my
antivirus screaming.

Get a less fussy AV.

Why not turn it off altogether?

I'll rephrase as you're thick. Get a more sensible AV.

And what %age of the plague would you like today sir?

It's really quite simple. Block things that harm your PC, don't block what doesn't.

The Honda CR-V manual is available on line. It has a 4-speed automatic
transmission. The owners manual says:

"For faster acceleration, you can get the transmission to
automatically downshift by pushing the accelerator pedal to the
floor. The transmission will shift down one or two gears, depending
on your speed."

... so you never get to the lowest gear.

You claimed above that you were surprised you could drop two gears. 3rd to 1st is a drop of 2 gears, which the manual you just read says is possible.

The only time it will drop down two gears is when it changes from 4th
(top) to 2nd.

Thanks for agreeing with me that a 2 gear drop is possible.

Did I ever say otherwise? What I have said is that you will not get a
2 gear drop if it is going to take you into low.

You certainly can. Don't forget, autos don't have a "1st gear". A small hatchback with a manual box might have 5 gears taking you up to 20,40,60,80,100mph. An auto will have 4 gears taking you up to 40,60,80,100mph.

On my current car that is the range of gears available
in D. I can if necessary manually select L which is 1st gear but the
engine manager will never select 1st gear once the car is under way.
That is the normal behaviour of most automatic transmissions/

It should select 1st if you put your foot down and 1st is sensible. Say if you're doing 5mph in a queue. 1st should allow up to about 20mph.

But they don't usually work that way.

Funny, my three did. Why on earth wouldn't you want 1st if it's available?

So there I am trundling along at about 1200 rpm and by going to full
throttle I am asking it to go to about 4000 rpm in 2nd gear. What
would you have it do? Slam it straight into 2nd and have the inertia
of the car jerk it up to speed? Or would you delay the engagement of
2nd gear until the engine was up to speed? I know which I would
prefer.

There is no jerk with a torque convertor. And it takes virtually no time to spin an engine up anyway. Try this - sit in your drive with the car in neutral at 1200rpm, stand on the accelerator. Look how quick it gets to full revs.

The torque convertor is not involved in the gear change. It's all done
by clutches inside the gear box.

Of course it's used, it's why you don't feel it changing gear. As you press the throttle a little, the engine revs increase but you stay in the same gear, this is the torque convertor slipping. As you press the throttle more, the car decides to change gear and the torque convertor adjust accordingly.

I certainly feel it changing gear. When I'm changing down there is a
sudden thump in the back as the power goes on.

I'd get that checked if I were you. Clunking auto boxes mean imminent failure.

When did I say anything about a clunking auto gear box?

"Sudden thump in the back". That kinda noise would worry me.

I mean the onset of acceleration - push in the back sensation.

Oh, I thought "thump" meant a worrying mechanical clunk. Well I don't get that either, although I've never had a very sporty car. The acceleration from an auto has always been smooth.

(Incidentally, your sentence has more or less brought us back on
topic.

What?

Please stop calling them auto!).

What other word should be used?

I am sure you will find one if you app yourself to a dic.

Everybody calls cars auto and manual. I see no need to avoid the word.

When I'm changing up as
the car accelerates I feel the change in thrust as the gear change. As
I have already said, the gearchange is not done by the torque
convertor. Certainly it may slip under the increased load but at the
higher speeds of fuill acceleration it is probably locked up.

The slippage is what stops the car lurching. That's why there is a torque convertor.

You ae confusing a torque convertor with a fluid flywheel. Torque
convertors have the properties of an infinitely variable automatic
gear box: you can have more torque coming out than you have going in.

Precisely. They allow you to have full power output halfway between gears.

Do you really think that power can be transmitted to the wheels in
those instants when no gear is engaged?

A gear is engaged. But you can have 3rd gear with a lot of slippage, which makes the revs/speed ratio equivalent to 2.5th gear.