EV button - what's the point?

You can delay the engine starting so silently leave an area if noise is an issue.

 

When you are in EV mode you can push a little harder on the pedal than you could in non-EV mode. If you aren't in EV mode and you get the Hybrid indicator bar beyond halfway the ICE will kick in. In EV mode you can push beyond halfway and accelerate a little quicker provided your battery charge is sufficient.

 

Buyers in North America wanted it. So much so they were adding the switch for it to their Gen II Prius. The function(not a feature) is already built into the operating system and was available to the rest of the world. No gimmick it's just a manual switch to allow fixed ev mode. You can also switch to eco and pwr and the "null" switch for normal. No big deal really and will be rarely used by most people.

 

For the average driver interested in average (for the Prius) fuel economy, there's not too much point in it, other than perhaps to show off to friends how quiet the car is tooling around the parking lot.

For some of us obsessed with fuel economy, it can make a significant difference when used properly in the right driving conditions. See this for more.

 

I use EV to keep the ICE off while I get away from my house and my neighbour's bedroom window when leaving for work at 6AM. Also to move quietly through carparks, and my engine never runs in my garage. I don't use EV often but I like having it.

 

Me too.

 

I have tried several times to activate the EV mode by pushing the button. Each and every time, I accelerate very slowly and at approx. 12mph it flashes a window that says the EV mode has deactivated. btw, there have been 7 battery bars each time. What's up with that?

 

I might be wrong but I the reason it's there is because the 2010 was designed to be a PHEV (Plug-in Hybrid Electric Vehicle) even though they delayed the launch of that functionality. As I recall there are some fleet ones that are equipped as PHEV's being tested around the world. It makes perfect sense to have this button on a plug-in.

 

I'd call it the "impress your non-hybrid owning friends button" as I think it's biggest draw is pressing it at the airport parking lot as you drive away to impress the friend who's never ridden in a Prius before.

Functionally, it really has little value. From a marketing standpoint hey 3 modes are better than two.

 

I use EV to keep the ICE off while I get away from my neighbour's bedroom window when leaving

LOL, is this what you guys really meant? That's the only real value I can see in it.

 

Mine also cuts out due to excessive speed at 12 mph with a "full" battery but it only does this when the ICE is cold. Once warmed up, I can always get up to 25 mph before it cuts out.

 

This does not work for me. When I start my Series V after it has been sitting for 8 hours or so (either overnight or after work), it always starts-up in electric mode (or certainly in quiet mode), but then the ICE kicks in after 30 seconds or so. So I don't get the "delay the engine starting" comment.

Regardless of battery charge level, I cannot get the car into EV mode (via the button) until after the car is driven for a minute or two or more.

 

As people have said, it's a niche use. I mainly think of times on summer vacation when it would have been nice when leaving early or arriving late with lots of tents or open windows around.

It's not quite as useful as the old days of V-8's though. I can remember starting cars, like an old-school Chevy Malibu, early in the morning and feeling like the whole world could hear you.

 

I was personally very impressed by how powerful it is. I use it to cruise in the neighborhood but most of the time use my foot to do it manually instead of hitting the button.

 

In my experience, the EV switch is worth something... but just how
much is highly dependent on driver self-discipline and the particular
drive/commute route.

I installed my EV switch because I just couldn't believe something that
seemed so cool could only produce the limited efficiencies that were
reported here... call it basic research. I've had the switch installed for
more than a year, that is to say through both warm summers and cold
winters.

Well, everyone was right: the EV switch is not the proverbial FE/MPG
"silver bullet."

In warmer times when the ICE and catalytic converter warm up in a
few minutes, the only use I've found for the EV switch is very short
runs imediately after the car is started -- backing out, and
immediately a 90 deg turn all at speeds less than 20 MPH.

Oh yeah, and the occasional ego-stroking to keep the neighbors in a
state of confusion as to whether or not the car is hybrid, or PHEV, or
full EV. Evil... but fun!

But even here, getting into and staying in EV mode at start-up is not a
gimmie. You have only three or four seconds after you hit the Start
button to make the transition. So, get all all the little getting-ready-to-
drive details out of the way before you hit the Start button. This would
include seat belts, parking brake, wiping windows, whatever. In my
experience, once you hit the Start button and the Ready light comes
on, you have but two or three seconds to engage EV mode AND start
the car moving. If you miss this, the HSD will revert to normal
operation and the ICE will come on and start the warm-up cycle.

Colder months are a wholly different matter. At these times the EV
switch can be a major element in recovering MPGs greatly reduced by
longer warm-up times/distances. (I do grill blocking, but no block
heater in colder months.)

A necessary aside: There are so darn many tricks and kinks to getting
really good MPGs that I get confused. So I try to distill things to broad
"rules" that are applicable in my mostly urban driving environment at
Posted Speed Limits, PSL, up to 40 MPH.
Some of mine are:
* Gas burned when the car is standing still is gas wasted.
* Gas burned to maintain speed, at constant velocity, is acceptable but
should be minimized consistent with safe driving.
* Gas burned to accelerate to PSL, or PSL + a little, is gas well spent
as then I can pulse & glide.
* Pulse and glide produces ~50 MPGs if the glide is 4 times the
distance of the pulse (constant acceleration). Pulse and glide at 6x the
pulse distance gets 70+ MPGs. In my experience, this holds more or
less true at target speeds between 25 and 40 MPGs.

Back to EV use in colder months -- well, cold but not really cold -- lets
say 30-45 degF. (One of the necessary conditions to get into EV mode
is the HV battery can't be "too cold." Exactly what that means, I'm not
sure. But I do know that after an overnight "cold soak" at 30 degF
outside temps, the HV battery is "too cold.")

The best use of the EV switch/mode is to suppress the HSD trying to
keep the ICE turning over and using fuel when the car is at a stop, or
to get into a no arrows glide below 34 MPH (Gen II) in EV mode when
the HSD won't allow it in the warm-up cycle. But even here this
practice is conditional; you have to have above ~110 degF ICE block
temps... the ScanGauge is a very useful tool.

In summary, Is the EV switch "worth it?" Definitely maybe. Properly
executed, I can realize 5-8 MPGs with very careful use of the switch in
my 28 mi. round trip commute. For somebody else... I don't know.

Also, in colder weather if you want highest FE/MPGs you must
drive through the entire ICE warm-up cycle without using the cabin heater.
If you use it you divert heat from heating the block and extend the
time/distance to fully warmed-up. One benefit of using the EV switch
is that in keeping track of all the conditions and details you are
distracted from realizing that your feet, hands, nose, and ears are
going numb.

As is so often the case, beauty, or in this case usefulness, is strictly in
the eye of the beholder.

Hope this helps.

 

I prefer my ICE cold ...