Classic Prius A/C question

[kirbinster]

I know that the engine has to run for the A/C compressor to work in my classic ('02) -- but I have a couple of questions. If I understood the manual correctly if you have the max button pressed the engine will run non-stop to keep the A/C going but if you just put it in A/C mode then the engine will only run when the car needs it so that the compressor does not run all the time and as such you may not get cooling going down a hill or sitting at a light. Is that a correct understanding?

What I noticed today at a traffic light was that the engine seemed to be running at a very low level even though it was not showing up on the MFD. If I turned off the air it seemed the engine stopped, but as soon as I clicked it on the engine would run at that very low level. It seems like a much lower level than when the engine is running at a standstill when it wants to charge the battery. Why does the engine running not show up on the MFD in this case????

[smasho]

What you are seeing is entirely normal. The MFD does not show when the ice is running. Rather it shows when the ice is providing motive power and when it is charging the battery. It is entirely possible and normal for the ice to be on solely to maintain operating temperature of the coolant or catalytic converter or, to run the AC compressor. To easily tell when it's running you need the Coastal engine run indicator.

Also, Max won't make the ice run non-stop. When the interior is at the appropriate temperature the compressor kicks off and the ice, if not needed for other purposes, follows suit. Max does bias the cycling towards comfort with the ice running more and the cabin staying at a more consistent temperature, non-max lets the cabin temperature rise more before the compressor (and ice) kick in.

Going to the electric compressor is one of the nicest changes from my old '02 to my new '05.

[Frank Hudon]

I still think Toyota missed the boat on this one, they should have made the compressor a hybrid like on the Accord. All they needed to do was run the motor shaft out the front and have the magnetic clutch on it. When the ICE is running it's driving the compressor and when it's off the electric motor runs it. Not very efficient to run the ICE to produce electricty to charge the battery and then use it to power the compressor. Just run it direct from the ICE, then when the ICE is off the computer turns on the electricity to run the motor.