new evidence that ECO mode works

I have noticed this as well

 

When AC is in Auto, the fan speed is at one bar till about 103F coolant temp (outside temp @ below 20F). Once above that the fan speed slowly increases as the temp rises.

So yes, your observation is quite right.

 

ECO definitely scales back the HVAC/Defrost/Fans, no doubt about it.

 

I can't remember the last time I had my car out of ECO mode. I've mentioned on various occasions how it helps in slippery conditions. I've notice the above as well.
All in all, I think keeping it ECO has saved a lot of fuel; it's a great addition to the Gen III.

 

I mostly leave mine in ECO as well. On really cold mornings where I'm trying to warm up the car, defrost the windshield, and keep the breath of 3 people from fogging up the windows, I will sometimes put it in power mode though. Power (or even Normal) definitely keeps up with that better. I can give up a bit of efficiency for sight and comfort over the first few miles of my travel, that's for sure.

Once everything is warmed up and the windows are clear and we are moving along I go back to ECO.

 

Other than a brief trial in the other modes when the car was new, I too have never used anything except ECO mode.

 

So the ECO details are starting to come out. Good to hear! As opposed to the constant statement, "its just fuel mapping". Blah, blah, blah. Still, it would be nice to see all the little details of ECO listed somewhere.

 

Aside from when first driving the car, I don't believe I've used ECO mode much at all. I'd say 95% of my driving is in Normal, 4% would be in PWR Mode and the only time I'd really use ECO mode was when I was driving on a driveway made straight of ice and had to back into a garage. The ECO mode sensitivity combined with the hill start assist really helped out in that regard.

I'm happy to see people getting good use out of ECO mode, but with my driving style it just doesn't cut it for me. I'm more of the 'get up to speed' and then glide sort of guy.

 

^ if you are getting 52.5 average in those other modes, who cares about ECO!

 

For those of us who regularly use adaptive (or even normal) cruise control, having some sort of confirmation that ECO mode relaxes some of the gain would be very useful. It's a very difficult thing to test empirically because it's just too hard to control all of the parameters (temperature, slope, wind, traffic).

 

Here's ECO mode info from the 2010 Prius Technical Overview doc (attached below):

B. Driving Modes
1. Eco Mode
a. Maximizes fuel savings across all driving conditions
b. Modifies or smoothes out the electronic throttle control
program to reduce throttle response
1) Reduces throttle opening up to a max of 11.6%
c. Modifies air conditioning operation
d. Also improves acceleration performance in low-traction
conditions like ice and snow as the reduced output
helps to minimize wheel slippage
e. EPA label calculations do not include Eco Mode and so
does not affect label mpg

 

Thanks for the data. I will be sure to read over the entire document. Of course, this doesn't make any mention of cruise control operation. Slowing the throttle response would of course help in any mode of operation (manual or cruise).

 

I am curious about the effect of ECO on CC operation also. I think from my observations the CC maintains a constant speed even on hills no matter which mode you are in. But ECO could modify the acceleration to resume to a preset speed, it might be possible to test that.

 

I've been using ECO basically all the time. Still, just just thinking aloud:

Maybe it promotes leadfootism, ie: you adapt to the very sluggish response, by tromping down further/harder on the gas?

 

I use ECO all the time, and in heavy snow (on my short non-maintained road) I find wheel slippage is further reduced by driving in B mode. Ihave no technical proof other than the lack of the traction control engaging in the same spots all the time.

 

I am curious about this too. Good suggestion, actually. I just bought an end of year 2010 II last week, and after watching all of the YouTube videos about no power to the wheels if they slip scared me. I will try this if I have driving problems.

Thanks!