Hi all:

A carefull reading of :

http://hillerford.com/resource_libra...capehybrid.pdf



This documents this :

http://www.greencarreports.com/blog/...weather-friend

H

 

Yep - good news because the ICE doesn't have to be running to use the A/C. Same on the FFH.

 

Yea but ( i could be wrong here) it looked like the 09's and the 10's have the same mpg rating. Like I said, I may be wrong but the links in the other thread said dat.

maybe the real world #'s will prove diff. here's hoping~!!

 

Hey way2muchkc4u

Judging from you location (Location: O.C. Ca.), you'll want to check out the SC03 results at EPA; that is the A/C test. So if you do a lot of highway at posted speeds in a hot ambient environment, mechanical A/C may be the way to go (or stay, you have a MY09) due to efficiancy. As long as you're willing to keep the ECON button on, for stop and go, during the two months when there MAY be 90 weather out here!

Enjoy!

 

The problem is that mechainical cannot not be modulated, moderated, when it's engaged it ALWAYS pumps over the required capacity. Whereas with an electric variable frequency drive the pump only need run fast enough for the current heat load.

The same reason most mechanical systems are now going to variable displacement compressors.

So I suspect that even with the lost in efficiency in converting mechanical energy to electrical to charge the hybrid battery the electric drive compressor still comes out on top FE wise.

Now if Ford would use the same technique, variable frequency electric, to drive a supercharger and be able to downsize the ICE.

 

The above statement about not being able to modulate mechanical pumps is just not true.

There are two ways to modulate a pump, or compressor, like an AC compressor in a car.

One is to use a swash plate (or tilt plate) inside the compressor. This varies the displacement of the unit.

The second is to use an electro-magnetic clutch to start & stop the compressor as the cycle pressures call for cooling.

The second is the less expensive and easier way to do that for cars.

 

Okay, I stand corrected. Yes, most of today's non-hybrid vehicles with A/C use a swash-plate type piston drive to vary the compressor displacement in accordance with load (is there an echo in here..??).

But I wouln't go so far as to call the ability to switch the compressor clutch on and off an ability to moderate or modulate, but each to his own I guess.

"..as the cycle pressures call for cooling.."

No, the way the system works is the compressor cycles on once the reservoir of previously accumulated liquid refrigerant is almost exhausted, in the meantime the call for cooling is continuous.

But neither of these is appropriate for the hybrids since the need is to switch the ICE off and still have cooling for a reasonable interval period.

 

The control of the cycling of the compressor is done with pressure switches not liquid level switches. These switches tell the system what the pressures are in the system.

wwest: you need to learn something about AC&R systems.

 

Yes, corrected yet again.

Once the liquid level in the reservoir rises to a high enough to fully/almost fill the reservoir the system pressure rise trips the "off" high pressure limit switch. These days this pressure switch serves a dual purpose in that it also prevents the compressor from cycling if the refrigerant level is too low, I.E, there is not enough refrigerant, gas or liquid, in the system to keep the system pressure above a preset minimum level.

 

However, the extra draw on the battery could cause the ICE to run even more than the belt driven pump!

It seems as if there are less and less driver controllable variables as the models progress...