70 MPH in a Prius in EV MODE!
 

I have been pestering a couple of guys in Chicago lately about plug in conversions.

Unfortunately, most Prius converted to PHEV suffer from only being able to go low speeds on electric only.

These guys were able to get one up to almost 70 Miles per Hour using only the electric motor!

Peep the video!
http://www.youtube.com/watch?v=QfkvygFJZDk

I took an interest in the bke recently featured on jay leno, this is even more interesting. I hope this becomes real and cheap, realistically cheap. the city chores, it would be nice.

Hmmm, very interesting. I'll definitly be looking up their web page today.

New VIDEO!

This time it's actually watchable!!!!!

http://www.youtube.com/watch?v=8y5n32p6u3Y

Again, veeeery interesting!

This is interesting but given the design of the MG1 and MG2 in the Prius engine it leaves alot to be discussed before deeming it "safe" for the Prius...it looks like fun but it may not be in the long run. When I first started getting into the Prius engineering (shortly after I bought it) I immediately was told "no neutral coast near or over 60 mph (and most people told me to avoid it all together). I still use it but no where near 60 mph.

The software that Ewert has created (and the upgraded battery pack they install with it) is still operating with the original Prius engine. Because of this the "gears" that simultaneously operate in the car ICE are still in play. The MG1 in that engine is built to sustain up to about 10,000 rpm (in the 62 mph range). In essence, the MG1 continues to spin when in EV mode to protect the engine and at 70+ mph it is clearly reaching it's limits before "overspinning" and doing harm to the engine (a poster on here showed me the math in my Prius thread if you want to reference it). This is something I am very aware of when doing any neutral coasting in my Prius (I don't do it anywhere near 60+ mph).

The software Ewart has created is basically a "hack" for the Prius engine system...it tricks the engine into thinking the SOC is high enough to use EV mode (thus allowing it to stay in EV at that high of speed...usually only available below 42 mph) and keeps it EV mode beyond the 41 mph limit. This is a problem in my mind because while EV mode is built into the car it is not built into the car at 42+ mph...really only up to 60ish mph where the MG1 is nearing "overspin."

Another area to consider is inverter temps at this high of speed and length of time while pulling higher amps to stay in EV mode using their system. Not only are you overflexing the Prius capabilities in terms of the inverter you are also spinning the MG1 at a ridiculously high rate. I'm no expert on the MG1 and MG2 in the Prius but I know that the MG1 spinning in neutral or EV mode over 60 mph is a no-no.

I'd like to see more in regards to what rpm's the MG1 is at while they are at the 65-70 mph speeds.

All very valid points Matt. I hope they address them. Time will tell.

Ewert has clearly developed an interesting product...and I'd be surprised if they engineered it to "fail" within the Prius engine system. They obviously intend to mass market the software/technology so it must have some sort of override that safely operates the vehicle.

But, I'd just be interested to read how it effects the Prius engine and what safety precautions it takes in regards to the engine and inverter. The fact that they install a larger battery to run the system says alot up front...they recognized the amount of amps to run that high of a speed required much more energy from the battery (like more than 3x more than the stock Prius battery). That being said, the inverter temps have to be addressed somewhere along the way.

If anyone has more info I'd love to see it...cost looks to be around $2k...not bad to get extended periods of highway driving gas free.

Of course that 2 grand is on TOP of the conversion cost to swap out to the BIG Nickel pack....

Matt, half of what you said is over my head. I am not much of a Prius guy... but I AM learning.

I just joined the PHEV discussion list and all the things you just mentioned are flying all over the place there.

A couple things I thought were pretty cool about this system is that it is possible to control the CAT warm-up. The USER could have control over when to turn the engine on and off. That REALLY opens up some possibilities in good fuel economy.

Also, even if you aren't driving 65 or 70 on this system, you can still go a bit faster than you could in a stock Prius while keeping the engine off, and you don't have to "reboot" the system to leave EV mode like you do with the Plug-In Supply system.


Another thought - On these conversions where the original Prius pack is completely replaced with a bigger pack, what happens to the old battery pack? How many needed to push a Geo Metro around? :thumbup:

Haha, the original battery packs are not big at all. The 1st gen Prius had a pack capacity of around 1.3 kWh, and I'm pretty sure they've been getting smaller ever since.

Hiya,

Really cool stuff! What is the size of the battery pack, and how long does it take to charge? What is the (average) range on the full EV mode, and in hybrid mode? And what is the MPG running in hybrid mode?

I think we need to use a hybrid rating in place of "average" MPG: say like 45 miles in EV mode + 60mpg thereafter (or ~500 miles on 11 gallons of gasoline, or whatever).

I agree, but that's for PLUG-IN HIBRIDS only. Your typical hybrids in America have no "electric only" capabilities. Of course this thread is about a plug-in conversion.

The car that this high-speed upgrade was done on is a Plug-In Conversions car.
See Frequently Asked Questions for general specs on their cars. Of course the answer to the "Can I drive the car without gas?" is changed by this new upgrade.

The size of the pack is 6 kwh and it replaces the existing 1.6 kwh pack...not sure on recharge time.

Ben,

An easy way to think of the Prius system is that it operates in 3 parts (the MG1, the MG2 and the ICE). All 3 work simultaneously with each other. When using ICE all 3 "parts" of the engine are spinning and working together. When MG1 spins forward, MG2 spins backwards...always on a counterbalance.

When in EV mode the rpm in the engine drops to 0 and the car runs off the battery alone until 42 mph and higher is reached and EV mode is replaced with ICE operation (MG1 and MG2 are not spinning under 42 mph in EV mode). This is where the "mystery" of the Ewert system leaves alot of questions to be answered. When in EV mode, around/near 62 mph the MG1 and MG2 reach their max load and become dangerously close to overspinning...at 70 mph I would expect severe negative impact on the MG1 and MG2.

Often, I will EV mode or ICE up to 41 mph, put it in neutral and coast down a hill "in EV mode"...this gives me the benefit of 0 rpm coast vs. ICE-on neutral coast (9999 mpg vs. 120 mpg on my SGII). On big downhills, I could leave it in EV mode and coast past 60 mph but I would also threaten the MG1 and MG2 by doing this. In these cases I will EV neutral coast up to about 55 mph and then either light brake or go into ICE to use engine braking to stay under 60 mph and overspin.

So, with the Ewert system at 70 mph in EV mode there has to be some "safeguard" to the system (I hope) that protects the MG1, MG2 and ICE from overspinning. Maybe it shuts the whole system down to 0 rpm and runs it off the larger battery. But, because the same Prius inverter is used to run the new 6kwh pack that ran the 1 kwh stock pack...running 110-140 amps at those speeds for the length of time they are doing it (10-15 minutes) would bring inverter temps beyond safe operation.

I've watched all the videos and read as much as I can find on it...but haven't found answers to these questions yet.

FYI, Bill Moore, editor of EVworld.com has posted an article about converting his Prius into a PHEV using the Ewert brothers' approach which permits the car to be driven at freeway speeds in EV mode.

EV WORLD: The Conversion of 'LIVN GRN'

Reading the article, I think it's safe to say this is still very much "beta".