ALL-Electric Prius

Hello Everyone. Steve Woodruff here, this thread has a great collection of very informed Evers.

I want to share A little history on the ePrius and where it leads..
( credits to follow later)

1. We learned that 52mph is about 13 mph too slow to be enjoyable.
2. Defining a goal or scope of the finished vehicle is necessary
3. the prius is capable of 70 or 75mph in EV *(when the I.C.E. is allowed to spin consuming a small quanity of fuel)
4. higher speed reduces range ( physics 101)

I was invited to participate with team Global-E to compete for the Progressive Automotive X-prize.
we stuffed a prius into a two door automobile with a 24kw lithium pack. we were eliminated when the heavy, not very aerodynamic car failed to achieve 100mpg during the 90 mile challenge.we were in the top 5. the very lightweight, aerodynamic vehicles performed better.

1. With this in recent memory the evolution of the ePrius turned to installing the toyota components into a lightweight body.
2. A 2001 Honda Insight has been purchased and gutted.
3. the goal of the project is an EV with top speeds over 64mph.
4. here is a link.Honda Insight with a Prius heart

now to address those folks who want to modify a prius to EV or PHEV.
our friends at P.I.C.C have a great solution for about 13500.
Our friends at Plug-in Supply also have a similar solution for about 9900.

and folks like yourselves who are building your own PHEV's or EVs

AutoBeYours sells components and also a new smartphone application for the prius.

with the help of Kiett and Brad we have a cool wireless prius phev dashboard with an optional pc board for state of charge spoofing and ICE management.


sub3marathonman , I see you are looking for a prius with a blown engine. Be advised we have not less than 17 Prius engines here.
they seem to last a very long time. I assume otherwise the spares we have would have sold by now.

 

pEEf, You are welcome and invited to pay a visit to AutoBeYours here in Southern Indiana!

 

Nimble, I like your idea of installing an electric motor where the ICE was.
this link to a prius power split device animation may help.
Toyota Prius - Power Split Device

 

I was just in Louisville last month, I wish I would have known about you then! =)

I might just take you up on that next time I'm out that way!

 

Hi All,

I was thinking about this some more. But really do not know the internals of the Prius transmission to know if this is possible.

The common thing that is done with synchronous motors is to stack them. For example a more powerful 23 series stepper motor will just have two rows of stator coils to make a "double stack" motor.

Could the MG2 end of the Prius transmission be cut away, and an additional Prius transmission portion enclosing MG2 be put onto the first transmission? Or, just mill that MG2 end flat, make a hole for an exteded drive shaft and weld on another MG2 portion.

Then to continue with Woody's concept, one or two of the cylinders would be cut out of the engine, and the engine welded back togetter without it.

The result is a 120 hp peak electric motor drive.

One might actually populate two of the cyinders, along with the plug-in or EV battery pack. And make a Volt , the way a Volt should have been made....

 

You see? it is a slippery slope! leading us back to spinning the existing ICE with a little fuel.

 

Any plans to make this available for iPhone users?

 

But that two cylinder version might get 90 mpg on the highway at 65 mph, and have a usable range of 800 miles plus....

 

Keep in mind, even after you do all this mechanical stuff, you still have to come up with an electrical drive. Also remember the Prius motors need 500 volts! You can not have any power at speed without this voltage. The stock boost converter is limited to ~20kw no matter what other hacking you do.

The most sensible option is to gut the transaxle, leaving only MG2 in there connected to the diff. Remove the ICE and replace it with a light-weight mounting solution, and put in a 500v pack. Then the only hacking you need is the ECU, as you can re-use the Prius IGBT-based inverter. You then end up with a 50kw EV, which is quite reasonable, as it will have plenty of torque. It will likely accelerate almost as well as a stock Prius. (keep in mind in a stock Prius, MG2 is doing all the real mechanical work off the line)

A true 120kw EV would be a tire-smoker with short range. A Prius is probably the wrong choice for a base vehicle for such a conversion. For a TV project last year I consulted to build an EV Hot-Rod using a 225kw UQM BLDC, and it would break the tires loose at any speed instantly, and did 0-60 in about 3 seconds. I can't imagine the need for even 120kw in anything other than a sports car!

 

Hi pEEF,

120 hp is approximately 90 kw. And that is only peak, not sustained due to cooling issues....

 

You can't really do an apples to apples comparison between ICE type horsepower to EV's. Electric motors generate almost full power at stall, whereas ICE's have to wrap up to high RPM to get them. A lowly 50kw electric motor (67hp) can easily perform like a 100 HP gasser.

The Prius motor is ever worse with it's atkinson cycle. Almost no torque at low RPMs!

I could see a 80kw (107hp) electric motor being about as much as you'd ever need for non sports-car like performance. If you are trying to build a sports car, then you need a platform with better suspension and vehicle dynamics. 120kw is a lot! My big electric van weighs about 7000lbs and only can peak about 60kw tops with a 45kw rating, yet it drives nicely.

 

Geat conversation! Looks like I'm a little late joining the party, but I'll stick my 2 cents in anyway.
I bought my Prius 2+ years ago. I started to think about building an EV. I looked at many candidate vehicles, and found that the Prius was the best choice. I reached this conclusion, because all the accessories, AC, brakes etc. are electric. It has a regen braking system etc. What it needs is more KW of electric drive. I considered what Jack wants to do, but thought it best to leave in the ICE for extended trips. I came to the conclusion that the way to proceed is to use 2 hub motors on the rear axle, and to servo the rear drive so that the Prius electronics thinks it is under light load. Not enough to start the ICE, just below that point. Now the Prius works just as it should, has regen braking etc, and my rear drive gives the extra push, and can be simple because regen is not needed. I would probably need to also spoof the Prius battery SOC so that the ICE doesn't kick in if not really needed. Now we have an exteded range EV with 4 wheel drive. When the rear wheel's battery back is discharged, the Prius reversts to normal hybrid operation.

 

This is actually an awesome idea, the only problem I can see with it is the unsprung mass ratio on the rear wheels is going to negatively affect road holding and ride quality. There's also the complexity issue, but that's never stopped a good engineer! =)

I bet the easy way to "servo" the rear motors would be to track instantaneous current on MG2. You could even do an analog transform function with a few op amps! (I know how you love the analog, Vertex! ;-) MG2's current is going to always mirror the load, and will go negative during braking. I guess you could also do the reverse, and connect the rear motors current control to the accel pedal, and the current signal from the hub motors would drive the original Prius accel signal.

Interesting! You going to do it?!

 

Hi Jeff as soon as we get correct MPGe calculations accurate, and a few other parameters, moving to iPhone is the next step.
I expect there are already dash aps for the i but the toyota message decoding is more vehicle specific.

 

Hi Jack!
I want speeds greater than 52 and that is my solution when using the toyota HSD ( hybrid synergy drive).
FYI the prius block wont fit inside the frame rails on an Insight.
but the original 3cyl would.
remember, I have many prius parts laying around and we tend use what is available.

I dont know of any other prius EV's ( I call it an ePrius)
but I am aware of a Hydrogen powered one, and an lpg prius.
This forum may produce a few others.
Like Vertex said, the Prius is an excellent platform for an EV conversion.

Donee, you say a 2cyl version may get 90mpg, The latest software release from Plug-in supply with their 10kw/h lithium kit already gets 180 mpg at 65mph. ( granted for only approx 40 miles) and fantasticly high MPGe at lower speeds.
Therefore I agree that a small combustion engine may indeed be adequate for what we may end up calling ICE assist. (ICEist?)

 

I don't consider the Prius to be a very good platform for an EV conversion. I suspect most people don't being that essentially nobody has really undertaken it. The reason I feel this way primarily has to do with the high level of computer integration in the car. Sure, everything may be electric but without the computer systems, it is nearly impossible to get any of it to work, including the instrument panel. When converting an older car from the 1980's or 1990's these sort of problems just don't happen.

I would never attempt a conversion of a Prius unless I was also an expert in CAN bus microcontrollers where I could design my own computer systems for the Prius.

 

Unfortunately this is becoming true for most all new cars now. I happen to be an expert in CAN bus microcontrollers, but I still can't really justify ripping the ICE out and losing the "dual personality" of a PHEV. Yes, a PHEV compromises EV range, and of course removing the ICE compromises overall range. You also have the hit of the battery weight on mileage when you take a long trip. Still, you only need one car! As someone that has owned (and loved) various EV's for many years now, I've also had to keep a gasser around fro trips. This has always been annoying and a reminder that EV's are just not "there" yet.

So now I'm getting rid of all my EV's and making my Prius be my "one" vehicle and attempting to make it the best PHEV I can.

Now if I was in a situation like Steve, who has a almost endless and local supply of parts, as well as plenty of space, I'd do a Prius EV in a heartbeat!

I think the electronic integration issues can be solved without much trouble. To me, solving a tricky CAN issue is a lot easier than say, solving the mechanical problem of mounting a 3-cylinder insight ICE to a Prius transaxle! Hell, I don't even think building a new HV ECU from scratch for EV purposes would really be that hard. That would give us full control over MG1/MG2 without limits.

As far as the instrument cluster goes, it's actually easier to get it working over CAN than it would be if it was just a bunch of analog signals. Most of the work has already been done by people documenting the CAN bus, such as Atilla Vass.