Passenger Air vs. HV Battery Cooling Air

I am trying to puzzle out the relationship between how passenger [hereafter,
"pax"] compartment air is handled as compared to HV battery cooling air.

I would greatly appreciate any comments, other sites, etc, on my thoughts
below.

What I think I know: (Windows closed)

The HV battery is cooled via air through the vent on the pax side of the rear
seat backrest.

The HV battery cooling vent is open all the time, that is, it is capable of
passing air whenever the pax compartment is pressurized. HV battery
cooling can be supplemented by a small fan in the ductwork that is
controlled by a thermostat inside the HV battery containment.

HV battery cooling air is exhausted at the left rear of the body, under the
rear fender plastic cover piece. For pix, see:

http://priuschat.com/forums/care-ma...g/37794-high-hv-battery-temp-cooling-fan.html

There are two basic conditions for pax compartment air circulation: outside
air and recirculated air.

When outside air is selected, the pax compartment is under a slight positive
pressure.

Outside pax compartment air comes from a plenum at the base of the
windshield.

My unanswered questions (Windows closed)

1. Where is outside pax compartment air exhausted?

2. If outside air is exhausted through the HV battery cooling ductwork, is
this the sole exhaust?

3. If outside air is exhausted through the HV battery cooling ductwork, and
the vent near the rear seat is blocked, can there be any airflow from outside
the car into the pax compartment?

4. If the pax air is set to recirc, then presumably the pax compartment is
not pressurized. If the HV cooling fan were to come on, where does the air
come from outside the car to allow positive air flow through the HV battery?

5. Does having the A/C running have any relevance to pax compartment or
HV battery air supply source or exhaust routing?

 

Bill and Pat,

Thanks guys. I won't block that vent. I've got to wondering...

Posts have reported that HV battery temps can be reduced by opening the pax
rear window for a while. I'm just wondering if, on really warmish days, you
couldn't help HV battery cooling along by supplying outside air directly to the
HV battery, without sending it through the pax compartment. That way it
seems like you could run the A/C at a reduced setting to keep cool yourself.

I am contemplating an insert for the rear pax-side window with a NACA style
duct leading directly to the HV battery vent -- overkill? First, I'm trying to
understand the airflow supply/exhaust in the car.

 

My thanks to the posters who have come up on this non-earthshaking
matter. This is purely a "thought experiment" at this point. From your
responses, it is clear that I didn't know as much as I thought I did.

From other inquiries I've made into the whole fuel tank/fuel vapor area, and
into the functioning of the brakes, it is clear to me that this is a vehicle of
systems -- and subsystems and meta systems. And so, intuition and logic
aren't enough to really understand what's happening. This lead me to a
suspicion that the pax air and the HV battery cooling air systems would have
some tight linkages.

Chap's post has a good example:

In addition to the air supplies and exhaust, I've thought about the pax air
HEPA filter. At first view, it seems much larger than would be necessary to
clean the air for human respiration. OK, it gets dirty so it needs to be larger.
It also must work at low speed/low pressure, as well as high speed high
pressure. It seems that it must also be sized for HV battery flow through. So
there's the probability that dust free air is better for the battery as well.

For viewers unfamiliar with NACA ducts visit this site:

SPEKTR PRODUCTS DUCTS AND VENTS

Well, a NACA duct would have no dust protection, and could in fact suck in
bugs, other stuff floating about, and even small birds -- I bet that would put
the nix on any warranty claim. Even though I see any such system as easily
mounted/unmounted, as Pat says, on balance it probably is not worth the
trouble/expense.

But all this does raise a non-linear thought. When there is finally a set
of good looking, rear wheel skirts/spats available, I wonder what the effect
of pressurizing the rear wheel well with a NACA duct in the skirt/spat would
be. :brick:

Back off boys and girls, its only a thought experiment ! ! :behindsofa: