Under the Hood Picture

blatt said:

Any new informations on that? I am curious on how the cooling system works. Are there seperated cooling circuits for inverter, charger, motor and cabin? or are they somehow combined?

Thanks for any information!

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You can check out the Owner's manual for free online: PDF. Jump to page 22 for a map of the motor compartment.

There are three "coolant caps" under the hood. One is for the heating system, which has a separate fluid system (1 7/8 quarts). AFAIK we've never really figured out why they used liquid in the heating system. The other two caps are for the motor/inverter/charger cooling system (7 quarts). One is a cap on the reservoir tank, the other seems to be a cap on the expansion/deairator tank.

Also there's 1 1/8 quarts of gear lube as per the owner's manual, if you were curious.
=Smidge=

Smidge204 said:

AFAIK we've never really figured out why they used liquid in the heating system.

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My WAG is that its for safety.. you dont want glowing red resistance heaters in a car.. it could ignite gasoline fumes or leaking engine oil. Look it up, its a DOT reg*









*note: I would not be surprised if it turned out to be true.

Herm said:

Smidge204 said:

AFAIK we've never really figured out why they used liquid in the heating system.

Click to expand...

My WAG is that its for safety.. you dont want glowing red resistance heaters in a car.. it could ignite gasoline fumes or leaking engine oil. Look it up, its a DOT reg*


*note: I would not be surprised if it turned out to be true.

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Assume it's because liquid, because of the mass, hold the heat longer and perhaps lessens the overall energy budget for heating. This is especially true if you are able to pre-heat while plugged in.

The heater runs on high (battery) voltage. The fluid loop keeps that high voltage away from the cabin. Seems like a better idea than exposed metal/ceramic elements or hotwire.

Also, it lets Nissan draw from the parts-bin of mature parts for in-cabin heater parts.. heating from hot fluid is a solved problem.

Because the fluid acts as a small heat mass to smooth out the temps, they don't have to be as careful about modulating the high voltage power. It can 'surge' heat just fine and the driver won't notice.
(If you had an insanely strong heater that came on once a minute to heat the cabin, it probably wouldn't go over well.)

Seems like a fine idea to me, anyway.. all the heat gets used anyway.

WRT the liquid heater, it was suggested by someone in another thread that having hot elements cooking contaminants picked up through the ventilation system would lead to unpleasant smells coming into the cabin. That makes sense to me, as do the ideas suggested above.

Anyone know how the heater works in the Tesla or the coming Ford Focus Electric? How about the Volt when it is in BEV mode?

The fluid used in the cooling system (motor, inverter, and charger)
is the same fluid as used in the Heater-liquid (heat circulating) system,
and both systems share a common expansion / overflow Reservoir
at the front Driver's side (just in front and a bit towards the center
from the Heater-Fluid Reservoir).

There is no Power Steering Fluid.
The LEAF uses an electric-motor assist type system.

The filler cap marked Power Steering in the picture above is the
Reservoir for the recirculating liquid in the Heater system.

The Brake Fluid Reservoir is up top, just to the Passenger's side of Center.

garygid said:

The fluid used in the cooling system (motor, inverter, and charger) is the same fluid as used in the Heater-liquid (heat circulating) system, and both systems share a common expansion / overflow reservoir at the front Driver's side (just in front and a bit towards the center from the Heater-Fluid Reservoir).

Click to expand...

It's true both the cabin heater and motor/charger/inverter cooling system share the reservoir, but they are operationally isolated. Except for small amount of flow to and from the reservoir from thermal expansion, the fluid in the two systems do not seem to mix.

Which reminds me - is anyone willing and able to take some temperature readings of the cooling system fluid? Say, after a typical drive home, stick a thermometer in the degas tank just to see how things are. Of course if it's hot enough to be dangerous to open, that alone would satisfy my curiosity...
=Smidge=

Smidge,

that is what I try to do. I want to place some sensors on the different systems. But its hard to find the perfect location. I think it is better to place the sensor onto a tube. So I do not have to open the reservoirs when the liquid is hot.
But where is the best place to measure the charger and inverter temperature as seperated as possible? Any suggestiions?

Thx.

Talk about bringing this back from the dead!

Gary and Smidge - thanks for updating this! I know we covered this in other threads but it's good to have current info here as well!