Silvex

I can understand "Never ask a woman about air temperature." etc.

But I'll need a bit of time to understand,
"The variable displacement compressor has a swash plate that rotates to reciprocate pistons, ...."
Oh boy!

I'm getting out of my depth here again.
But I love it!

What other exotic technology have we got under the hood that nobody else dares to tell us about ... ....... ?
Thanks again, lobuxracer.

Silvex

lobuxracer

iTrader: (2)

For the visually inclined, here's a YouTube video on how the compressor works:

Silvex

lobuxracer, earlier I said "The idea that when the A/C indicator in the Nav screen (multi-function display screen) is illuminated (yellow), really does mean the compressor is working, right?"

You then said "They mitigate the losses with a variable compressor for the A/C. It's actually pretty impressive ....."

Just to get this clear in my mind.

Are you saying that :
a) our variable compressors are always running, when that yellow A/C indicator light shows and,

b) the compressor in less sophisticated cars may well be in stand-by mode even when a A/C indicator is lit. When the compressor in those cars does cut in, it runs at full power, all of the time?

Silvex

lobuxracer

iTrader: (2)

Yes. That's how it works as I understand it.

Silvex

Ok, thanks for confirming that.

Silvex

Silvex

Great stuff. Thanks.
Now I at least know what a swash plate looks like!

Silvex

digger08

iTrader: (1)

That video is really amazing....but they couldn't get a real person to narrate it for 5 minutes?



Digger08

Silvex

Yes. It's strange when the voice says "A stroke C" isn't it?

Silvex

Silvex

lobuxracer, on 02/22 you said "Both are required to be in the auto mode .........."

Hmmm ...
In my car, I'm sure Auto Intake Control mode works even when Auto CC is OFF?
That is, the AIC green light is lit.

If I'm right, do you think that alters anything we've been discussing?

Silvex

lobuxracer

iTrader: (2)

The US version will not engage auto on air control unless auto for the system is also engaged. This may be a market difference.

Silvex

Ok. Mine definitely can engage Auto Air Intake Control without Auto CC being ON
So I'm happy to put that down to a market difference.
Thanks for clearing that up.

Silvex

Silvex

On 02-23-14 lobuxracer said:
"Since there is no humidity sensing input, the system assumes outside air is too humid and will not save a bit of petrol needed to run the heat pump when outside air into the cabin would be completely appropriate."

Could this also be why the following happens when A/C is OFF?

OAT around 13C
A/C off
Auto CC off
Touch screen shows settings as Face/LO (blower)/Temp set at 20C
Auto Intake Control is in Outside Air mode

If Temp is reduced to LO

The system will automatically go into Auto Intake Control Recirculated Air mode.

Why?

Is it because as lobuxracer says, it does not know what the OAT is.
Or, it assumes the OAT is too warm.

So it does the best it can, and just recirculates the air.
That would be no better or worse than before ....
It can't cool and dehumidify it of course, because the A/C is OFF

Have I got this (speculation) right?

Silvex

lobuxracer

iTrader: (2)

I agree with your line of thinking. I am convinced the software controlling the system assumes the A/C is always on, even though it should be aware it is not. It does very nonsensical things (or at least they seem to be to me) when your configuration is anything other than automatic.

Silvex

"I agree with your line of thinking."
Thanks for that vote of confidence :-)
It helps a lot.

" I am convinced the software controlling the system assumes the A/C is always on, ..."
Yes. I'd never thought of that. It could explain a lot of things.

I suppose it would save the designers, engineers and programmers a lot of time, trouble and last but not least, cost.

Who else but you and I, and few of the others, regularly run the CC without A/C being ON.
So why bother building in that functionality if very few are going to use it.


Could I bounce another speculative thought in front of you and the others?

Re. my "Could this also be why the following happens when A/C is OFF?"

Am I right in assuming that our cars have an Air Mix type of heat control?
As opposed to a Water Flow type.

If so, could this also, be happening when "If Temp is reduced to LO"

An Air Mix system controls the volume of air allowed to flow over the surface of the heat exchanger.
It uses an air mix/blend control door fitted inside the heater assembly.
The control door directs air over or _bypassing_ the heat exchanger depending on its position.
The position is determined by the occupants of the car who select a temperature range from hot to cold.

In my example, we have selected LO

So the system will completely bypass the heat exchanger.
Because no heat is called for.

In addition, as I said earlier, the system switches to Recirc mode
"So it does the best it can, and just recirculates the air.
That would be no better or worse than before.
It can't cool and dehumidify it of course, because the A/C is OFF "

I suppose the system would still do that when A/C is ON i.e bypass the heat exchanger.
The difference being that the air passing over the evaporator would rapidly cool the cabin.

Even so, does that make sense?
Could that be happening when A/C is OFF?

Silvex

lobuxracer

iTrader: (2)

It is unquestionably an air mix system. Toyota have not done a water flow system for quite some time. The last vehicle I had with a flow valve was my 1988 GTS Corolla.