EV Button Use Strategy Discussion

When I leave my house with a cold engine in the morning, I either climb the big hill or jump on the 70 MPH highway. Each involves a wait at a stoplight. But despite both being such a burden on efficiency, the system typically delivers 30 MPG for the first segment.

So the clear benefit of the EV button for me is in situations where I don't get a minimum of 30 MPG, like when I leave work. That involves waiting for several stoplights, all within the span of a 1/4 mile. The first segment is typically so low it is a horrifying sight... less than 10 MPG!

Being able to just crawl along using nothing but electricity for that initial short distance would be fantastic. I could simply defer the warm-up process to when I get out on the open road.

 

I only drive about a mile to work, on my way to work I use EV ( 3~4 bars left when I arrive ), on my way home I drive it normally and it recharges just nicely. I don't know if I'm going to be doing this in the long term, but my Prius certainly made people look at the crossings...

... not to mention the "geek factor"... I love taking my collegues from the R&D lab to lunch...

( What I will end up doing most likely is to drive in EV mode until I leave the housing complex and get on the main street, which is like half-a-mile. )

Nevertheless, it's a great mod and I appreciate all your works!

http://www.vassfamily.net/ToyotaPrius/index.html

 

mostly gut feel response here, but i'd let the computers do the decision-making most of the time and use the option 2a and circumstances like that for EV only. i'm not driving one yet, but it occurs to me that the only times i'd really like the IC to not be running is in a parking garage, entering or leaving, and in my own home's garage, to keep any hydrocarbon emissions out of my garage, home, and nose.

any time you take to the highways without warming up any engine is bad for it. i once drove my dad's '63 chevy to work one winter, and there was little choice after work but to get onto the 55mph highway home almost immediately. it drank oil at about a quart a month because the pistons and rings didn't have time to expand and fill the gaps, but it didn't seem to hurt the engine. just blow a lot of oil past the rings and maybe some seals.

just my 2 cents for now.
good questions, though!

 

I'm as envious as all get-out, but there's no way I'd attempt the mod. My typical trip is 10 minutes. Five minutes of warm-up at 25 mpg, followed by 5 min at 50 mpg. All city streets at around 30 mph. I would like to use the EVb to draw down the battery on the last couple of miles, so that when I start out cold, and the engine has to warm up, but not much energy is needed to move the car, that excess ICE output could be recharging the battery. As it is, my battery is almost always near full. Once in a great while, when the ICE is warm, I'll get a stretch of electric mode and see 4 or 5 bars. But not often. I'd pay $500 for a Toyota-certified EVb that would not risk invalidating the warranty.

 

> any time you take to the highways without warming up any engine is bad for it

Some will actually do exactly that due to non-explicit comments.

That's where the need for a "guide" comes from.

For example, my definition of "open road" (as in my prior comment) meant a sustained 30 MPH cruise afterward. But someone could easily think I was referring to a faster speed.

Anywho, if not used wisely, the EV mode could easily cause MPG to be lower. Just look at how common the "slow acceleration" misconception is.

 

I think there's a decent chance you'll be able to get that, for a lot less than $500, in the next year or so. Just a gut feeling, but I think Toyota will realize that people in the US want it and, if they can get through the EPA BS then they'll be able to offer as an aftermarket mod.



Just to chime in if TMC is watching, I know they want to "mainstream" the car for the US market and a manual switch per these methods may have too much "geek" factor for the image they want, but a full time switch on the logic of the power selection algorithm (like changing shift points in auto trans cars) could go a long ways towards accomplishing much of the benefit of the EVb described here and not require constant intervention.

 

My '04 Prius actually seems very reluctant to go into electric mode. If the SOC is okay, and I'm cruising along at 30 to 40 mph on a level road (all roads are level in Fargo) and I let up a bit on the pedal, I can get it to go into electric mode for a while.

HOWEVER...

If I am going slowly (10 to 15 mph) it never seems to go into electric mode even when the SOC is showing 7 bars green. Only by coming to a full stop, waiting for the ICE to shut off, and then keeping down to 6 or 7 mph can I keep it in electric mode.

If I slow way down and pull into a parking lot and then drive 5 to 10 mph for a considerable distance, it never goes into electric mode. Again, even though the SOC is at 7 bars green.

 

Initally before we got the EV button I thought I would be saving a lot on my commute home. I usually get 58-70 going to work and 38-44 coming home on my 11 mile commute. It's a net downhill to work and slightly uphill coming home of course. The traffic is always jammed up at one section for 1-3 miles. 5-10 mph and slightly uphill. Even with the SOC green, I can rarely make it through that section using the EV button. Once the ICE starts up in the pink zone, my savings quickly go out the window and one day I posted my record low of 38 mpg.

So my new approach is moderation, which seems to be working better. It's great for backing the car out to wash. Sometimes at the start or end of my commute where I know I'll only be sitting at a light for 2 min while the engine runs I'll use it. If I see the SOC is all green and I know I'm approaching a long downhill I'll use it there too. One neighborhood on one of my routes home has about 12 15 mph speed bumps. So you get the car up to maybe 25 or so and you have to slow down. And it's a very slight uphill too. The ICE constantly kicks in there so having a high SOC and the EV button helps a lot.

 

Both my home and my workplace are on the top of a hill, by using the EV option I am able to delay the firing of the ICE. It seemed to be such a waste to go down a hill nearly a mile long with the ICE running and not contributing to the propulsion of the car. I also do not use it if the batterly level is below the half way point since I think wide fluctuations in the battery level could result in premature battery failure. I do like the "control" of determing when the ICE is going to start.
Garrett
'04 Salsa Red #9

 

My work is at the bottom of a 900 foot drop four-five mile downgrade. I've overcharged the battery each time I come down the hill. I think I am perfect for this EV button because I should run the whole way to work without starting the ICE and arrive with a full battery.

Coming home is a different matter...I'm learning to leave two or three (prefer four) bars on it so that when I do get the EV button, it won't start up the ICE.

So, would I be a good canidate for an EV morning commute?

 

am i the only one here who wants an EV button just for the coolness factor? it would be nice to pop it in stealth mode just to turn a few heads while cruising the strip. most people i show the car to are more impressed by the silence than anything else.or maybe i'm just shallow...

 

Yes it is pretty cool driving through a parking lot in ev mode only. Could be dangerous if the don't see you coming. Today I posted my best round trip commute using the button sparringly. I had 69.2 mpg to work and 42.7 mpg for the 11 mile commute home. I just can't break the 43-44 mpg mark on the drive home with the 1 mile of nearly stopped traffic uphill, followed by more hills. But at nearly 56 mpg and at about 59 degrees and foggy weather I'm happy. I did finally hit 2 pink bars at the end of the 1 mile of very slow traffic to start up the ICE but by then the speed had improved.

 

b)Where it clearly is NOT a benefit:

When attempting suicide by CO asphyxiation in a closed garage, best NOT to have the E/V mode turned on! :angel:

 

I've never been overly fond of living in Florida until now. The flatness of this entire state is ideal for the Prius - so far the best I've done is 37 mph without ICE (at constant speed, not at a slow deceleration) - I can only assume there's a sloping grade on that road that isn't detectable by the eye, it has to be less than flat. I drive that road several times a day, and it's about two miles long, but on gym days I run it at 4:45 a.m. - I LOVE having the windows down and the radio off. It's so great when you can hear crickets at 35 MPH! :mrgreen:

 

So can someone please confirm for me,

If I enable EV mode, the ICE never comes on ? or does it just engage later than usual (or when the battery gets too low).

I am worried that my wife wouldn't know if it was engaged or not and might deplete the battery unknowingly.

 

The ICE will still come on IF:

1. You go faster than EV mode permits;
2. The SOC drops lower than the computer likes.