same here, always have it on and it still gets the car cool.

Also, I was told this same thing about the compressor, it makes sense.

 

For a complete explanation of how ECO works, see post #17 here
https://www.greenhybrid.com/discuss/...56/index2.html

then ... see of the attached .pdf file that Stan provided. For the reason I stated thet cabin temp would not be cooled below 77 degrees, see page AC 28 of the same file. Thanks again, Stan!

 

Keep reading the thread. You'll see plenty of people who disagree (and even the PDF is inconsistent), and even a couple who tested it out and found it does indeed go well below 77 degrees. It simply doesn't allow full power operation below 77 degrees, but falls off to a lower power level. This means that in very hot, sunny conditions it might not go below 77, but it can at other times. In the PDF, see the very last page for a chart of AC power versus temperature. It never drops to zero.

Remember that the manual is translated from Japanese and sometimes things are lost in translation.

 

I don't think it limits it to 77 degrees whenever the ECO button is on, it seems much cooler when its set low. There is an easy way to test it though, test the temp. I will see what i have for a thermometer and test it if I remember.

 

I am not an engineer, so totaly understanding the specs and charts in the PDF is a struggle for me, but this quote from page AC 28 of the PDF seems to confirm my impression.......

"...To decrease the cabin temperature to below 25°C
(77°F), the MAX COLD temperature (18°C (64.4°F))
must be selected or ECO mode control must be
canceled by turning the ECO switch OFF..."

I assume the reference to 64.4°F is the "LO" setting on our US TCH, which we all know turns off the ECO mode.

I guess an additonal question I have, is this...Does the ECO mode do anything while on a long distance high speed drive, (highway) when the ICE isn't likely to shut off anyway?

From last page of PDF "...This prevents the SOC (state of
charge) of the HV battery from decreasing and
increases the amount of engine OFF time,
improving the fuel economy."

I hope someone can clear this up for us, as this pertains to the original question of this thread...what effect on mpg does the ECO switch have? This may depend if we are talking about in town or on the highway.

 

The electric A/C compressor is powered by a variable-speed inverter circuit from the NiMH battery. This allows the controlling ECU to vary the compressor's speed, and hence the amount of heat that it can remove from the cabin per minute, independently of the ICE's rpm. For a given outside temperature, this heat removal rate will determine the lowest cabin temperature that can be achieved (the A/C evaporator temperature is always much lower than the cabin temperature). Clearly, one doesn't want to waste energy, and this system can be designed to be more frugal than an ICE-driven A/C compressor. The ECO switch limits the power draw by the compressor, and this will thus limit the lowest cabin temperature attainable at a given outside temperature. If your requested temperature is above this limit, then you will eventually get it; otherwise you won't, unless you switch ECO "off." This means that you can indeed achieve a cabin temperature below 25 degrees C (77 degrees F) with ECO "on," provided the outside temperature is not too high. Switching ECO "off" will get you there sooner, and use more energy in doing so. I would expect that only in the hottest climates is it necessary to switch ECO "off." Certainly, I leave mine "on" all the time.

Since the "hit" that your FE in mpg (or FC in L/100 km) takes from using the A/C depends on your speed (don't forget that you also have the A/C "on" when you're sitting at a stop light), asking for the corresponding decrease in mpg (or increase in L/100 km) is not the right way to assess this. The meaningful measure is the additional fuel usage rate in gal/h (or L/h). I gave some calculations of these numbers in an earlier thread. See posts #14 & 17 of the thread "Effect of Air Conditioning on mileage":
https://www.greenhybrid.com/discuss/...05/#post175255
https://www.greenhybrid.com/discuss/...05/#post175421.

Stan

 

Thank You. This has been my experience as well, but I didn't want to create an argument with those who say otherwise. Even here in balmy Houston with our heat and humidity, I leave mine set to Eco and have no probelm maintaining 74 degrees inside the cabin.