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My Dream car! 13 EX-L
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Discussion Starter · #1 ·
I've read that the AC works different when using "ECON".

I know we have a thermostat that controls when the compressor cycles on and off.

Does someone here know more about what regulates when the AC compressor cycles on and off?

Reason I ask this. I've had vehicles that seemed like the AC compressor was on most (not all) of the time. I not sure but it seemed like the heater duct door would open to keep the cabin from getting too cold.

What internal devises control the temperature inside our I4 EXL accords during summer months?

Thanks
p.s. I did take AC and refrigeration after high school, but that was in 1978. Things have changed, like automated controls & no more r-12. LOL
 

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My answer to a somewhat similar thread was (and I may be wrong) is when you have AC on, the compressor runs and cycles on and off all the time. It cycles so it doesn't ice up (the evaporator, I believe). If the ambient temperature is below, like 40 degrees F or so, the compressor doesn't run even when you have AC on. Temperature is controlled not by how much the compressor runs, but by mixing doors which mix warm air from the heater core (which is always present) with ambient cool air, or cold air from the AC. And AFAIK when you have the car in ECON it stays in "recirc" mode more often. It's been my experience it is not in recirc all the time when ECON is on, just more often and maybe at lower temps.
 

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My Dream car! 13 EX-L
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Discussion Starter · #3 ·
Thanks HondaBob.

I sort of figured the blend door was operating. What a waste of gas.

About 23 years ago I had a (bullet proof) 72 Merc 220D. The AC for some reason was not performing as I wanted. I hard wired a home AC 120 volt ceiling fan thermostat in the cab and took control of my thermostat (compressor cycles). Worked fine and saved even more fuel.


Now teach me how to do this with the IC. PLEASE!
I get tired of hitting the "AC off" button just to save gas and wife won't allow me to touch it while she's riding. LOL
 

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Thanks HondaBob.

I sort of figured the blend door was operating. What a waste of gas.

About 23 years ago I had a (bullet proof) 72 Merc 220D. The AC for some reason was not performing as I wanted. I hard wired a home AC 120 volt ceiling fan thermostat in the cab and took control of my thermostat (compressor cycles). Worked fine and saved even more fuel.


Now teach me how to do this with the IC. PLEASE!
I get tired of hitting the "AC off" button just to save gas and wife won't allow me to touch it while she's riding. LOL
I don't think turning the compressor off or on will make that much difference in your performance or your milage. If it does make a difference, I would give up a little gas milage to be cool any day of the week in the summer here in Texas.
 

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It has been proven on Mythbusters that running with AC on at 60 m/h is equal running at 60m/h with AC Off & all windows down in fuel consumption :)
 

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It has been proven on Mythbusters that running with AC on at 60 m/h is equal running at 60m/h with AC Off & all windows down in fuel consumption :)
No argument with AC on the highway vs. windows down. In stop and go traffic it might make more of a difference.
 

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There is a temperature sensor mounted on the evaporator that is used to cycle the compressor on and off to maintain an evaporator temperature just above 32°F. The compressor does not cycle directly with outside or inside air temperatures, although it does indirectly because these temperatures can affect the evaporator temperature. There are also low and high pressure switches that monitor the low and high side pressures which will also cycle the compressor if the pressures go too low or too high as can happen if there is a blockage in the system or an incorrect refrigerant charge or if the system load is too high.

Interior temperature is controlled by mixing air cooled by the evaporator and air warmed by the heater core and not by cycling the compressor. The reason for this is you want the evaporator to stay cold so the system can dehumidify the air for human comfort and to reduce interior glass fogging. Using the compressor to control temperature is a bad idea because once set point is reached, the compressor will cycle off. Dehumidification will stop and the remaining condensed water vapor on the evaporator will go right back into the cabin resulting in swings of temperature and humidity. The Crosstour was the first US Honda that allowed for limited control of cabin humidity in addition to temperature by cycling the compressor off more frequently. Some high-end luxury makes that allow humidity control in addition to temperature control will also limit compressor on-time to allow for increased humidity where possible. The system cannot add humidity - it can only somewhat control the amount removed.

Some vehicles (many GM models - not the Accord) use a variable displacement compressor that varies its displacement between a minimum and maximum amount in proportion to evaporator temperature or system pressure instead of cycling on and off. This dramatically reduces clicking, surging, and compressor clutch wear. A variable displacement compressor is bit more complex and costly. "Import" brands seems to prefer cycling compressors over VDCs.
 
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