EV-1 Conversion

[JCG]

An important day comes to an end. The last thing I needed was to get some open-road speed tests for the car (basically, motor phase current or DC power draw vs. steady speed) to get parameters for the overall propulsion model. This afternoon, Chris and I loaded up a trailer that he borrowed and headed out of the District and into the wilderness of Maryland.

The trailer, unfortunately, had a front railing that kept us from raising the tail ramps all the way...


... so we hacksawed that off and things fit like a glove.



Perfect parking spot when we grabbed a bite to eat on the way out of town:


We reached the undisclosed location in about an hour. This car sure does look nice on a sunny day.


We spent the next hour or so taking data on a flat stretch of road with minimal traffic. It was a little monotonous but still fun to be out in the open. On the last run back to the trailer, we switched off the charging circuit (engine still running) and Chris floored it to see what kind of speed he could get on caps-only power. Listen and you'll hear the tires squeal.


I now have the data that I needed. With all the work/study done up until now, I have enough to start putting together a technical paper that I'll try to get published in either IJAT or as an SAE technical paper. That's new ground for me, but I think that this work would be appreciated. If all goes well, I'll post a draft link here before any copyrights get signed over.

So, that's the end of the line for me and the EV1. I'll be headed to greener pastures over the summer (south Alabama) to start a new job there in June. If I had this whole project to do over again, I'd definitely do a few things differently. That's a good thing to be able to say, since in the end I firmly believe that I learned a great, great deal overall. I appreciate everyone following this project on ES; it was definitely easier to do this work knowing that others gave a damn. There were a lot of late, lonely nights drilling holes and wiring things up in a cold, dusty, dark, leaky, stagnant-aired, rusted-out, crumbling building that's overdue for a wrecking ball - but I do want to express my deepest thanks to Chris Harriman, Eric Cardwell, Jeff Baxter, Charlie Wermine, and Santa Claus (name withheld!) for the key parts that they played along the way. I'm proud of what we accomplished - a completely mothballed and disabled vehicle was brought back from the dead. Couldn't have done it without you guys.

Most of all, I must say thank you to the main source of financial support, General Motors. The GM engineers with whom I've discussed this project understand just what a magnificent vehicle the EV1 was - let's hope that forward-thinking engineers might hold more sway within the company in the future.

The vehicle will remain an asset of the University - as a teaching and research tool. The next researcher and research team will undoubtedly learn as much as I did when they next open the hood (or trunk!) and get to work. Until then...

"She rests in silence, dreaming of the day she'll run free"


(Sorry for the cheese. But I think I'm entitled.)

[GCinDC]

Wow. Wasn't ready for that ending! You put so much work into it! Oh well, good luck in AL!

Are you gonna print out this thread and leave it in the glove compartment as a manual?

What was the top speed in the vid?

[paultrafalgar]

Very well done, Jason! I too am shocked by the end of the project. I hope you will encourage whoever takes it over to continue posting news here. All the best in your new job. Best wishes.

[JCG]

Thanks Paul - I guess I got everything accomplished that I set out to do, minus the ammonia carburetor conversion, but I'm actually a bit glad that we didn't go down that road just yet - things became too rushed here as the year began. Also, it leaves the door open for a better engine-generator set to test out in the open in the coming year or two. Carbureted is not really the best way to go, so it's time to start learning about fuel injection, spark advance, air/fuel ratios... in a high compression SI engine. Stationary application first, but I also would really like to start a vehicle from scratch, maybe that will be possible as a separate research project for next year. One of the problems with the EV1 was how little space there was inside, using whatever was left over from the pure EV design, which was not much at all!

Greg, as George Bush would say, "Mission Accomplished." I'm not 100% sure if there even is a glove box... but I will be in close contact with the guy from Mechanical Engineering who will likely be the new custodian of the work area, so I'll give him all the info I can. And the wet/dry vacuum.

As for the top speed, I am in the process of figuring it out. The only thing that's clear is that the conversion that I used to correlate the displayed "motor RPM" (0-10 V signal) to motor frequency, to wheel RPM, to vehicle speed is way off. When we started tests yesterday with a progression of 20, 25, 30, 35, etc. mph cruising it was clear that we were going much faster than those speeds at the voltage displays I'd calculated. I'm going to check with the controller's programmer soon to see what factor I missed or misread. Anyway, it seemed that we got up to at least 75 mph a few times, although my conversion factor suggested only 45 mph from the display. The good news is that all the data is still valid, I just need to translate it by a constant multiple. Worst case, I can raise the front wheels and use my laser tachometer on the tires while checking the display.

[TylerDurden]

Stellar work. Thanks for sharing it here on ES.

Look forward to your next!

[fechter]

Sorry to see the project come to an end. I hope the next custodian of the EV1 will share with us too.

[JCG]

TD & fechter (as I finally spell your handle correctly) - much appreciated. I'll definitely recommend posting of future work - the people at ES are on the whole extremely gracious, generous, and helpful! I'm glad that no matter where I go that I'll still have an account here (until I get banned! ).

Best
Jason

[GCinDC]

taking the trike with you?

[JCG]

Paper draft is written and under peer review.

Link to PDF

If anyone has specific comments or questions, shoot me a PM. I've already spotted several grammatical errors, the kind that only become visible after you hit the "submit" button.

I can keep this up until I sign away the copyrights. Please don't distribute over e-mail - download from the link. Thanks!

[paultrafalgar]

I read your elegantly written thesis. I found no typos or grammatical errors - I didn't check the maths - not my strong point. But one thing bothers me (not wishing to rain on your parade):
From page 26 we have:
"These fuel economy values are equivalent to 42.3 city and 72.2 highway miles per US gallon."
The Volkswagen XL1 concept car (http://www.volkswagen.co.uk/volkswagen- ... e-in-qatar) is quoted as having a fuel consumption of 313 mpg (I don't know if that's US or Imperial gallons), but it seems a lot more than your figures which are similar to current Prius levels.
I am surprised at this. Would you conclude that Serial Hybrid is not the way to go (the VW appears to be a parallel-hybrid) or that several million dollars and a big research team can optimize the design where a one-man band can't be expected to compete.
Would your EV1 conversion benefit from the incorporation of in-wheel motors (e.g. Michelin Active Wheel) do you think?
Best wises,
Paul

[JCG]

Hi Paul,

Wow, that is a nice car. I would have liked to have found ready access to a small TDI diesel for this conversion, in fact that was my first choice before being lured to the carbureted engine side where modifications to the air intake and spark ignition would have allowed for gaseous ammonia fuel (which of course wasn't delivered as promised). I also had trouble finding a diesel that would fit in the trunk. Anyway, let me try to get to the point of your question.

This VW concept car is actually a series-parallel hybrid (Pruis style). The motor and engine may assist one another, but the car can be propelled by the electric motor alone. It's distinct from a Prius in that it (apparently) may achieve significant range on electric-only propulsion at speeds greater than the Prius' maximum electric-only speed. This ability to move under electric-only power without the engine running at all is what can cause hyperinflated "miles per gallon" efficiencies to be reported for these types of cars. For example, if I were to take the Chevy Volt with its 40 mile electric-only range through ten consecutive runs on the UDDS driving schedule, it would travel 40 miles without a drop of gasoline, for infinite miles per gallon. The old EPA methodology was to use a distance of 100 miles of mixed city and highway driving (40% city, 60% highway if I recall correctly) to evaluate economy. You may remember the 230 mi/gal claim that GM made a while back. To make up for this, the EPA has split the ratings for the Volt into "all electric" equivalent miles per gallon and a gasoline-driven mileage too. The electric to gallon of gasoline equivalent (gge) is about 33.7 kWh/gge. So now the Volt is rated at 93 miles per equivalent miles per gallon while going electric-only, and 37 mi/gal once the engine turns on. Those are mixed city/highway numbers, too. I'd like to see a similar analysis for the VW concept. It looks very slick (low drag) and is extremely light. I'm sure the true efficiency number is well over 100 mpg on the high way at a not-too-excessive speed.

So what I'm saying is that this kind of comparison is definitely not apples-to-apples, and gets very confusing very quickly. Probably the best way to do the fuel economy calculation is to say that, "driving this car for a week puts this much CO2 in the air, and/or costs you this much money." I like the money angle.

Lets say that my next door neighbor and I are coworkers, and we don't carpool. He has a Volt, I have my converted EV1. We each drive exactly 40 miles to and from work five days a week. He never needs to fill up the tank, and the EPA lists his cost per mile at $0.04/mi for a total of $8 per week. The combined city/highway mileage for the EV1 conversion comes out to 60 mpg (I think). If we pay $3.75/gallon here in Alabama, that means if I drive 200 miles a week I'll pay $12.50 for my weekly commute. The Volt wins.

Now let's say we each take a 200 mile leisurely road trip on state routes (mixed city/highway), doing the driving in one day. He gets his first 40 miles with no gas used, then starts using gasoline at 37 mi/gal. He'll pay $16.22 in gas. If I go the whole way at 60 mi/gal, I still pay my $12.50. Things look even better for the converted EV1 if it's an extra long cruise at highway speeds (my mileage at around 72, his at around 38 or so according to what I've seen published for the Volt).

I'm cutting the Volt a break here, because it also uses premium fuel - which is about a quarter dollar more expensive per gallon around here. Anyway, bottom line is that I'm pretty pleased about the numbers as they came out from a 34% (at best) efficient carbureted lawn mower engine!

As for hub motors, I think they could offer a lot of better options for a production car, if they could be made inexpensively. They were definitely not an option for this project, but I'll be watching the field to see what progress is made for their development. I will definitely keep an eye on the Active Wheel.

[grindz145]

Sad to see the project go Thanks for the video though

[JCG]

Published!

Plenty of editorial delays, but the manuscript was finally accepted once I cut some of the "lecture" material out and streamlined things. I'll post a link to the article once it publishes - look for it in the Journal of Automobile Engineering (Proceedings of the Institute of Mechanical Engineers). Thanks again all for the support and motivation! It's very gratifying to know that all the time and effort will be communicated through this publication.

Best,
Jason

[dnmun]

hey, congratulations on getting published. now i know how old i am. i first coauthored in '74. congrats.

[JCG]

Thanks Dan. Forgot to post the online link like I'd promised. Here it is:

JoAE

Also, relocated to the Colorado School of Mines in early May. Looking to get a student project on EVs going once I meet the right people.

JG