EV Button Use Strategy Discussion

IT DID IT!!!
The weather warmed up enough that the snowflake disappeared the other day, and I was stopped at a light and the ICE was stopped. I pulled away gently (nobody behind me) and got up to 18 mph before the ICE kicked in. I guess it was just too cold before now.

 

I just made another test drive today and the Prius ran fine at 55 km/h (almost 35 mph) on electric motor alone.

 

I'm up in the Northeast (NYC 'burbs) and just picked up a Tideland this afternoon. On the first trip I had no problem running it EV-only up to about 30mph. Luckily (For them) there was no one behind me.

Avergage mpg for the initial 3 short trips (very mixed driving, including highway and hills) is 47.5 mpg so far.

I can get very used to this.

--Gene

 

There is also a temperature level above which the ICE will come on as I recall. I don't know if this is battery or engine temperature related. I think for some reason I encountered that the other day. I kept getting the 3 beeps when I tried to enter ev mode. The SOC was all green with the last bar unlit as usual. I could hear the battery fan running when I listened to the exhaust vent in the back seat and it was slightly warm. I tried over and over again at stops with the high SOC and could not enter EV mode. The AC was off although I think I heard the engine fan and the interior was warmer than normal, only 70 degree day but sunny. It acted normally the next day and was able to use EV mode easily. This is the only time I've encountered this and I'm still sort of puzzled what caused it unless something was too warm. I did not just come off of a heavy EV use either.

 

You can't get into EV if you press the button when:

1. Vehicle speed is above 55 km/h (34 MPH)
2. Vehicle is accelerating and needs ICE assist
3. ICE is not suffieciently warmed up
(But you can press the EV button right after the startup (in 7 seconds?) before the ICE starts.)
4. SOC is low (3 and below?)

The item #3 is somewhat complicated. According to a Japanese site, there are 4 "stages" in THS (1 or 2) depending on the coolant temperature. Obviously, S1 will not allow you to start EV mode.
Note: all temperatures in celcius.

S1: (below 40C) ICE runs no matter what.
S2: (40C - 69C) ICE stops when not in acceleration
S3: (above 70C) "half hybrid" or "idle check" stage
"If the coolant reaches 70C, the car is in S3. In this stage, if you can't go up to 55km/h, the ICE will not stop no matter what you do until you come to a stop and wait 10 seconds. If you reach 55km/h and above, the ICE stops when your foot is off the gas pedal. But the car will be in S3 until you stop for 10 seconds."
S4: (above 70C) If you stop with shift positon "D" in 10 seconds or more, the ICE stops and you are finally in S4 or "complete hybrid". The behavior is the same as S2.

They say it is very important to avoid S3 as much as possible to improve the MPG (or km per litre).

If you don't see 99.9 MPG when you (think you) are regenerating or gliding with no arrows from the ICE, you are in S3.

Here's one interesting usage of the EV button. If you are in S3, you can press the button to temporarily stop the ICE. But it won't get you into S4. You have to come to a complete stop and wait for the ICE to stop.

US owners have a lot of benefit with a thermos to avoid S1 as much as possible. If you park and restart while the system is hot, you start from whatever stage, depending on the coolant temperature.

Tosh
Salsa Red BC
San Diego, CA

 

Tosh,

This was actually after I left from lunch with you. I drove home and had to stop at home depot for maybe 10 min and then came home on the surface streets. I had been using the ev mode out of the parking lot. Since I had been on the freeway I'm sure the car was warmed up. I was at a point where I tried over and over again to enter ev mode with the button while stopped. The engine was not running and could achieve stealth mode the usual way on flat ground, low acceleration. I was very baffled about this since I've been using ev mode a lot. This has not repeated yet. The only thing curious was that I seemed to have to green SOC no matter what I did on that short 5 mile surface street run. Very strange.

Since I'm going to the dealer to have it aligned I no longer have the ev button and may not put it back in. Yes it's very cool but I'm not sure I've really benefitted that much and I don't want to have to hide it or remove it everytime I take it in for a service, worried what the dealer might do if they see it. If it ever gets approved I'll probably reinstall it because I love scaring my neighbors as I creep up on them while they're out walking, lol. Thanks again for you help with the handling issues.

 

Fred,

I just posted your questions to a Japanese site forum. Hopefully someone will respond by tomorrow.

 

Page 12 from European Prius Owner's Manual. Could be helpful to EV button enthusiasts.

 

I am a little confused about S3. I think it means the following:

If the coolant was below 70 C, and it reaches 70 C while the car is moving, and you are moving slower than 55 km/h, you remain in S3 and the ICE will not stop. You can then make the ICE stop, and move into S4 only by either exceeding 55 km/h or by stopping for 10 seconds.

Can someone tell me if I have this right?

Aslo, S2 seems to mean that the ICE stops when the car is not accelerating, but the car will not go into electric (stealth) mode, although it can draw power from the ICE and the battery simultaneously.

Is this correct?

 

So that sticker says if the hybrid battery is too warm or cold. I think my case may come under the former. I've never heard the battery fan before but I did that day. I didn't want to run the AC and so the interior was warm because of the sunny day although it was in only in the high 60's outside. I could feel warm air coming from the batter compartment. And there's the high SOC for such a long time that I saw. Some kind of conditioning cycle or something? But I don't recall the ICE running when stopped. I tried many times while at the stop light to go into ev mode and I think after about several pushes it did once but it came out almost immediately after I started slowly and would not enter again.

 

Is the battery fan you're referring to the one they warn you about in the owner's manual -- the one by the rear right seat that you have to be careful not to block or cover?

 

First of all, some corrections in Temperature and speed thresholds. See below

In S3, if you go above 60 km/h, then stop accelerating, the ICE stops. If you end up below 60km/h, then coast, the ICE won't stop. Until you come to a stop for 5 seconds and more, you will stay in this mode forever. If you find the ICE is running, increse your speed above 60 km/h, if you can. This will temporarily stop the ICE. But you are still in S3. I know it's complicated. I'm still not sure if I fully understand it.

Hmm, interesting point. But you can press the EV button to force it, though. (At least they confirmed this.)

 

Tried EV at the dealer today (option is included in Australian model). It worked exactly as I expected. Drove around city backstreets in stealth, as soon as speed picked up, the ICE kicked in, but much later than without EV.

Placed my order today for Merlot Red (same as Salsa in US version), full options pack.

 

On the instruction, it mentions the "indicator light" and it shows a smaller picture of the EV icon. Does this show up on the US owner cars that have performed the modification? Has anyone seen this light lit?

I am guessing that any option that isn't installed on a car is not going to have the necessary wiring/lamp/indicator/whatever installed. Imagine all the cars delivered to the US with a lamp installed in a socket that would never see the light of day. (Sorry! just couldn't pass up a chance for a pun!) If a manufacturer is going to save on costs, it's 'Don't install anything unnecessary'.