I don't think it can because the way a Prius works is a bit funny in that it actually requires the ICE to run during certain speeds of operation, regardless of the state of charge on the battery. They have talked to Toyota techs and after much discussion came to the conclusion that it was not possible to run a Prius in EV mode at all speeds. In theory if you replaced the ICE with a third electric motor, you could do it, but such a conversion would be no less difficult than doing a full EV conversion on any car, only probably more so in a Prius.

In terms of labelling it a 100mpg or whatever, I think it still really depends on the individual's situation... Some people will get 100mpg, some may get 120, some might only get 60... as with a normal Prius it's highly variable, and in such a limited quantity it's even harder to calculate an average.

I think the 100mpg "grade" given to the Prius+ is fairly accurate for people who would be using the car to commute, since it can be charged at home each night, and/or at work if they let you plug it in. Like you say if you go on a really long trip that would certainly drop, but in normal use I think the label is fine. The idea is to show how much less gasoline you would be burning within normal use, if it were to indicate what mileage you get in other unusual situations the string of numbers would simply get confusing, although technically more accurate.

I don't thin the FEH will get 100mpg though, with no EV button it will be harder to stop it from burning gas as it normally does. Perhaps if they work with Ford on hacking the firmware it could, but otherwise I suspect it will be quite difficult to improve the FE as much as has been done with the Prius.

 

I keep thinking this is a grey area. My Prius gains *all* of its motive force force from Petrol, so I agree that it is not an EV. A PHEV Prius, on the other hand, in city driving can pretty much live off the grid up to about 30 miles/day/recharge.

Even on the CalCar site, they say that the 2G Prius EV threshold of 35 mph cannot be exceeded. I don't think this is true. AFAIK, the threshold is about 6 kW with a full battery, which is a fair bit higher than 35 mph onl level ground in my experience.
I suppose in the end it will be a political decision, but I personally support cars of this type as EV, or EV equivalents enough.

 

What Felix or Ron at CalCars meant by the 35 MPH threshold is that EV mode is automatically overidden by the ECU when the speed approaches 35. My EV mode kicks out at 34.5 MPH.

 

And I will add that I can regularly hold in EV to 40 MPH or just a bit more, if careful. Ron seemed surprised that the number for the FEH was that high. That is good. He had heard anecdotal information that the number was closer to 25 MPH.

 

If I take EV to mean arrows on the MFD flowing from the battery to the wheels, and no other arrows, I can reproduce that easily, up to 49 mph. I actually just went for a drive to verity it ..

Admittedly, I cannot step too hard on the gas, so the power available at higher speeds is limited, but I cannot identify a 35 mph threshold.

 

I think the 35 MPH threshold is when the three beeps happen when you are in "forced" EV mode, and it returns to normal hybrid mode. You'll need the EV button 'modification' for North American Prii in order to do this, but the only real advantage is that the acceleration can be pretty substantial without the ICE coming on when in this mode. 'Round here it cancels at 55km/h

When not using forced EV mode it can continue to use the electric motors exlusively for longer, but the ICE will spin without using gas after 35 so that MG1 doesn't overspin. I think this is what people call 'warp stealth', but I may be mistaken.

 

Thanks for the explanation, Schwa

How does that situation compare to 'glide', meaning no arrows on the MFD as far as what the ICE is doing ?

 

Coasting, or glide would depend on the speed of the car too, as far as I can tell. The motor/generators have 3 modes essentially, drive, generator and free-wheel. They can provide power in either direction, as well as regenerate power, but in some situations they just spin without using power or generating it. It's hard to know for sure what the ICE is doing at any given moment without having a monitoring device that interfaces with the car's electronics.

A great site that goes into a lot of detail on the Prius drivetrain is http://home.earthlink.net/~graham1/M...riusFrames.htm
Click on the "What's Going On As I Drive?" link for some animations of the PSD and good explanations of what's going on and why.

 

Thanks to Mike (sdctcher) and the others for their thoughtful comments.

Of course we're aware of the issues raised in talking about 100 MPG cars (and 500 MPG flex fuel cars) -- we try to include the footnote "plus cleaner, domestic electricity and other fuels" when possible. One good place for a summary of the main issues is the PRIUS+ Fact Sheet.

Here's the quick summary of our goals with Escape:

The non-profit California Cars Initiative is now beginning to explore the feasibility of converting the Ford Escape Hybrid into what is variously called "plug-in" or "gas-optional" hybrid (PHEV or GO-HEV.

That's what we did with PRIUS+, attracting national attention (see http://www.calcars.org/kudos.html). That even led to a private company (http://www.edrivesystems.com) building more advanced version and now planning to seel installed after-market conversions. For the technical details of what we did, the PRIUS+ Fact Sheet (current version is 1.8) has lots of information and pointers to many resources. For the latest developments, subscribe to our free news archive http://groups.yahoo.com/group/calcars-news .

Our fundamental goal is to persuade automakers (of course, including Ford) that there's a market for these vehicles, and that it can be to the company's benefit (as well as society's) to move first to 100+MPG (gasoline) plus electricity GO-HEVs and eventually to 500MPG vehicles -- fueled primarily by electricity for local travel and biofuels for extended range.

We hope to propose to Ford that they cooperate in our efforts and those of many others to offer vehicles first to the public and private fleet market (see http://www.calcars.org/calcars-opportunity.pdf). But we're not yet ready to make formal contacts with the company.

When we started our project on the Prius, we were able to benefit from many long-established online networks of people who had "deconstructed" the car. We then established our own "open-source"-style discussion group (see http://groups.yahoo.com/group/priusplus/).

Because the FEH is so new, we're beginning by gathering basic information. We have had some contacts with people who have been involved with the development of the FEH, and Mike Maline, the moderator of the Escape Hybrid Yahoo group, has been very helpful.

We don't yet have our own test vehicle, so we plan to start by checking out privately owned FEHs. If you live in the SF Bay Area and you're in a position to help, please contact me or Ron Gremban, Technical Lead, rgremban@calcars.org. Thanks in advance!

 

I'd like to know how you do that since I really can't get it going very fast w/o the gas engine kicking in. Basically, it only remains in EV mode in a parking lots.

I'm especially surprised to hear you say that since page 6 of my 2005 Hybrid Escape manual states "Under normal operation with the vehicle at operating temperature, the engine will start authomatically as you accelerate. Sometimes, the engine will start immediately as you begin moving, while other times the vehicle will obtain a speed of *up to* 25 mph (40 km/h) before the engine starts." (Emphasis added)

That sentence "Up to 25 mph" seems to indicate the top the EV-only mode speed.

Hence my question on whether there are alternate ROMs or hacks that I can do to get a higher EV speed.
https://www.greenhybrid.com/discuss/...-etc.2741.html
It seems amazingly stupid to have the top EV speed to be less than 30mph, the standard 'in town' speed for most roads in the USA. Perhaps the battery is too small, the electric engine too weak, or the car too heavy.(?) But maybe they just didn't want anyone to notice any reduced performance. However, I'd be willing to trade higher FE for reduced performance. THAT IS WHY I BOUGHT A HYBRID!