ECO Mode and Cold Weather Performance

I have a bit more info about engine on/off and the water temperature for stop-and-go driving while in normal mode.

The transition seems to be when the heater control is advanced to position-5 or higher. Then the engine will cycle on at 137F and off at 148F (instead of the 114F - 130F range).

While in this range, it's possible to turn the engine on just by changing the fan setting from bar-4 to bar-5, and turn it off by lowering the fan setting from bar-5 to bar-4.

Also, if you leave the heater completely off, it seems to take about 3 - 5 minutes for the water temperature to go from a cold startup (currently about 27F) to 103F where the engine will then turn off.

I've decided that I really like the information that the ScanGauge provides. It's currently showing the RPM and the water temperature along the top row, with the instantaneous MPG and the average trip MPG along the bottom row (I'm in Canada, so it's actually set to L/100km, but that's user configurable). It's really nice to be able to directly read the instantaneous MPG as a number rather than try to interpret it from the bar that the car shows. The average trip MPG reading is generally slightly worse than the car's display (by about 5% - 6%), but sometimes it's the other way around, usually during the first 10 minutes of the warmup phase.

 

My new Prius III and I live in hilly eastern PA. Two weeks ago, I had my 1st experience driving the Prius in snow. The road conditions were the worst I have seen in my 13 years of living in the area - fresh new snow, 30 deg. no road treatment, about 3" of snow on the road. I was driving in ECO mode, my 1st experience was braking where ,even going slow, I needed the ABS to help me stop; about a mile from home I had to climb a hill, the wheels started to spin, traction control kicked in, I was careful to not give it too much gas but discovered I had floored the pedal and was losing speed??, I let up on the pedal and traction control kicked in again and I slowly made it to the top.

I am confused by how this "drive-by-wire" car behaved in this instance. What happened when I floored the pedal? I did not feel that I was spinning the tires and was not getting the right-left grab typical of traction control until I let up on the pedal.

Other than this strange behavior, I was pleased with how the Prius handled in these terrible conditions. After I topped the hill, I had to go down the other side and found that the ABS kept the car in a controlled slide without fishtailing.

 

That is the traction control. I was misled too. Our Kia van has that active TCS which applies the brakes and makes a helluva racket. The Prius is different. You might get some initial spin but it will back off to maintain a steady rate. After getting use to it, I think I like it more... it feels more stable.
Others here will provide a more detail explanation I am sure.

 

I am a new Prius 2010 owner and am confused about this NORMAL mode. The panel provides 3 buttons: EV, ECO, PWR
Is this PWR button the same as NORMAL?

 

NORMAL is when no button is pressed, a 4th option commonly overlooked.
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The buttons are toggles -- you push them once to engage their function and you push them again to cancel that function.

No functions selected is "normal" mode.

 

I live in the same general area and had to drive in the same 2-3" of snow that suddenly showed up. The roads in teh Philly burbs were a mess. I didn't have any troubles with hills, thankfully. I live in Manayunk, so I don't know why I got so lucky. Could it be because I put the car in PWR to get maximum control of the gas in those conditions?

I'd like to know if this will help since we're slated to get 6-12" tomorrow in Philly.

 

I have just posted on another thread about my experience with cold weather (down to -16C in Munich) and ECO mode.
Eco Mode in Cold weather - impressions by Pakitt in other thread.

Definitely ECO mode is the way to go in cold weather. I read a lot about grill blocking, but I don't know if the car is designed to be used that way and I wonder if something happens to the engine, if Toyota would consider the warranty void due to the grill blocking. Actually in Winter weather my impression is that the engine does not turn on any more often than in mid-season, and, though not heard, it will almost never run the cooling fan for it. The engine is often off and will keep cool - normal cars will have to use the cooling fan even in cold weather since they are always on. Except diesels maybe; at -17C once, my Polo hardly reached 80C water temperature...the cooling fan never turned on...

 

Since coolant temp never rises above the usual level (with just the lower grille blocked entirely), there would be nothing related to heat. In fact, you are far more likely to see higher temps without any blocking at all in the dead of summer in the south.
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I always run ECO. Botom grill fully blocked, except the one spot (1in x 4in) that puts air directly onto the sensor. Upper grill 75% blocked. I come up to 140degF fast and run between 140degF and 190degF never going above 203degF. I find that the ICE is easy to shut down. I can get up close to 60mpg on the gage but at the same time the SOC drops. I can easily get down to 2 bars. My last 1/2 mile home is all EV. I park at 2 bars and then it comes back up during the warm up on the next day.

Because the batery goes low I tend to not worry about driving with slow accelerations doing long the battery only glides. I still get 50 to 52mpg average on the gage.

Thanks,
Dan

 

Are you referring to the sensor for the outside air temp (OAT) that displays on the console inside the car? If so, where is it located that you left an opening in your blocking? I blocked 100% of the bottom and have noticed the OAT is now much slower to change. It takes quite a while after leaving my garage for the OAT display to reflect the true OAT.

 

The sensor is behind the lower grill on the drivers side. I was actually thinking about relocating to behind the upper grill as I don't plan on blocking it. There appears to be plenty of slack in the wires to do that.

 

Hmmmm ... ya know ... I don't know what it is ... but I generally don't lose any MPG's because of winter ... I had my car delivered in Jan of 2010 and it immediately started out at about 48 MPG and it has pretty much STAYED right there. I was looking forward to a gain in the spring and summer but really didn't get it due to very hot weather and required AC use. My best tank on a trip was 57.6 and I have never gotten less than about 46 MPG, averaging out with tanks of 50 or so to average right at 48. I have a scanguage, so I always know what my car is doing. I'm surprised to hear about the big cold weather hits that some cars take.

REV

 

Yup ... that'll do it !!

REV