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SDSU Enigma hybrid-electric sports car
Who said you can't build a parallel hybrid with 20 miles ZEV range? Not the team at San Diego State University. Close Up

It's An ENIGMA

Part 1 of an exclusive interview with Dr. Jim Burns.

By Josh Landess

Contributing editor Josh Landess again probes in depth a remarkable story of ingenuity, vision and determination that lead to the creation of San Diego State University's remarkable, 80 mpg Enigma diesel-electric hybrid sports car. This is part one of his serialized interview.

EVW: It's the news of the day, and I want to get your opinion on the contrast between your program and these well-funded companies and their teams of engineers that have spent nearly US$2 billion over the last five or ten years on the PNGV. That PNGV program has ended. And yet you've built an eighty-mile per gallon vehicle. Why are people claiming it's so difficult?

JB: Well, the nature of large enterprises and well-known individuals with big names is that they can't risk enough to be assured that the outcome is worth the risk. They hedge their bets.

A good classic example is the Hypercar Project initially started by Rocky Mountain Institute. Here's a case where there's a four-passenger all-composite mini-van concept car. The structural details, the running gear.... that's all together I understand, but I haven't heard that they've put an engine in it. And I'm wondering how long it will take them to go out and try something to get it on the road. Even if they don't hit their hundred and twenty mile per gallon figures or hundred mile per gallon figures that they're claiming, will they at least attempt to see what current technology will do for them and learn from that?

Big car companies and even these kind of research efforts, if they don't hit their target the people involved are really too embarrassed to go forward.

We were nobodies. We were from an obscure school with no program but we did it right. We built the vehicle that they should have built a long time ago. We simply didn't have anything to lose. We could take as many risks as we wanted to. Our reputation wasn't on the line. We could only win.

EVW: There are times when they should make a concession and be willing to do the off-the-shelf-thing and just get it on the road? Like with the engine?

JB: Well in their particular case the approach has been to make an extraordinary light four passenger vehicle with the hopes that the propulsion technology would come along to satisfy the needs of the vehicle to be driven down the road. I don't know whether it's to be used as a sort of a stick to try to stimulate growth of more fuel-efficient power plants, but my understanding is the vehicle sits in the research facility and is not being outfitted with any power plant until such time as one deemed efficient enough to hit their goals is brought on-line by somebody else.

This seems contrary to the natural instinct to prove the system out, put any modern power plant in there that will fit, drive it down the road, get some data, and then you can make solid claims about what the ideal power plant might do for you.

We didn't have any of those luxuries. We don't have eight to ten million dollars of funding. We don't have the large groups of sponsors, investors and consultants working on this project. Instead, we went and bought the best, most capable technology right off the shelf, made simple basic assumptions and choices, did our homework and built a system that is highly producible right now.

Is it producible in quantity for a profit? Well I don't think that's really our job, and I don't think that that's necessarily Rocky Mountain Institute's job either. I would like to see somebody step up and produce the vehicles even if they're not profitable for driving yet. And have the guts to then make them a product that people can afford. Put the mark out there and say we have achieved the technical goals. Now let's try to drive the cost out of this product.

None of the big companies seem to be willing to do that except for the Japanese. And they have done that. They introduced products at a loss, and they've been working at refining them. That's a very acceptable strategy. That's how you generate market share if you're really committed to it.

EVW: And the losses that their critics are claiming seem a little like nit picking at times. I don't think the losses they're experiencing are that drastic. They do seem to be able to reasonably anticipate some profits in it going forward.

JB: And they're in a position now to have learned the other lessons that make maintenance and marketing and other aspects of the business proposition work well because they're in the game. Let's see someone else get in the game. We built this car initially on the idea that somehow someone would want a high-performance, hybrid sports car. And if you follow the traditional model of technology introduction in the major car companies here in America, new advances go into the high-end vehicles with enough profit margin in them that they can afford the extra investment. Those are introduced to the public, lessons are learned, the technology trickles down, becomes commoditized, and it ends up in your family sedan. That model was inverted and has remained inverted for this particular kind of [hybrid] technology. You don't see that. The high-end cars don't incorporate this.

EVW: Maybe they would tell us that it we taxed petroleum, it would give consumers an incentive to buy higher-mileage vehicles?

JB: Well you know you're really hitting on a key point here I think and that is the battle right now that may be waging, that will determine whether or not large car companies get off the fence, is one of infrastructure. The fueling infrastructure will drive the next level of technology because those monied interests seem to have the ability to control which technologies are going to be supported by tax incentives and major research programs.

The latest Bush announcement supporting fuel cell development: what that requires is an entirely new fueling infrastructure. Right now we're trying to cater to a conventional pump-grade infrastructure and because our vehicle's a plug-in electric hybrid we're also satisfying the grid infrastructure that's out there.

EVW: Oh, you are a plug-in operable as a pure-electric?

JB: We are. We have a twenty-five mile electric range. So we're hitting those two conventional fueling structures, but there's a lot of money to be made and a lot of money to be lost by car companies if they guess wrong on what the new fueling infrastructure's going to be.

Vehicle Essentials
EVW: What else was necessary to get the hybrid aspects of the vehicle going? Did you have to design a transmission?

JB: We did. There are four or five elements that had to come together here.

One is we needed a re-configurable body plan, one for which the internal space could be done with as we wished. What that meant was that whatever body shell we chose, we had to fit all of our material into that, all of the structural and mechanical and electrical system had to go in there. It was helpful if we could kind of pick and choose where things went.

Now, many of the university efforts in this country were based upon donated bodies and vehicles from The Big Three. If you wanted to go back and make the best hybrid that you could, why would you want to hamper yourself by having to avoid cutting a piece of structural material inside of a Ford Taurus or something and then having to go back and worry, is my car safe now, or is it structural?

They are unlikely to share with you the design information, or the CAD models about their body. And so the competitions that these vehicle fabrication efforts are based on typically don't allow you to make any structural changes. Well that is a serious limiting factor in being able to make great choices about the rest of the systems if you can't move this wall here and add this member there, to make up for it, and really have control of all the structure. And the end result is you tend to not be able to hit the highest level of performance. We wanted to start with a clean slate, so a good body, open form, essentially a hollow shell, that we would put a structural chassis inside of, was our choice.

Two: The highest power to weight ratio electric drive was necessary for us, and AC Propulsion's was the one. It had the grid charging ability; it's just a wonderful piece of technology. And it was small and lightweight. And in a small car, you need that. If you're talking about driving a bus, the weight of these propulsions systems isn't as important a driving factor, but we needed a small overall package size, and light-weight, so that our vehicle, in this small size, would be able to perform as we wished.

Three is we wanted to go after the most fuel efficient, practical, consumer-demand-driven kind of a recharging ability onboard. What could that be? Well fuel cell is an option, but where is the fueling infrastructure? At least three years ago there was no mention of that.

If you're talking about one of the various kinds of combustion engines that's available, gasoline is a natural choice and that's where the Prius and the Insight are at. But, at the same time, you're always going to suffer some of the efficiency disadvantages of the thermodynamic cycle involved, even though I would say the combustion engine technology has gotten more efficient.

We knew we were hedging our bet because the diesel cycle is inherently more efficient--higher operating temperatures and so forth. Diesel fuel was a logical choice in terms of economics too, in terms of the cost. And its availability out there, just not anywhere, but almost anywhere, that was a major consideration: having an efficient power plant to recharge our load leveling device, in this case batteries.

Four: The best of electric vehicle technology at the time was emerging, the new batteries were coming out. Because of the PNGV activities in the Advanced Battery Consortium, people had a lot of hope that batteries would advance quickly enough to allow for all-electric-drive technology, but we were getting better batteries at that time anyway.

The question is what is the cost of ownership and what's the upfront purchase price, you know, we went with lead acid batteries. But, these are pretty advanced lead acid batteries and, as a commodity product, we reaped the benefits of a lot of other people's hard work. So that energy storage was a choice.

The fifth element is the transmission. I may be corrected in the future, but at that time we did a fairly thorough search, those many years ago, to try to find anyone who would put together a small, lightweight, parallel format transmission that would handle these kinds of performance loads.

I mean if you're looking at the torque from a diesel engine and an electric motor of these capabilities, there really hadn't been any way to merge those power streams that you could buy off-the-shelf. So we had to develop one, and it's the linchpin of allowing for true parallel format, regenerative recharge through the diesel engine. . .

It is allowing all those advantages that you would want to see in an over the road car, and in a format that we could fabricate here. Toyota's approach is to have an integrated motor-transmission kind of a drive system in the Prius. I haven't really looked carefully at what the Insight does. This was a linchpin of doing what we had to do.

Vehicle Specifications & Projections Table

AC Propulsion's Groundbreaking V2G Drive
EVW: About how much is this AC propulsion unit, or is there public information about it?

JB: Actually there is, if you go to the AC propulsion website, it is extremely thorough in showing what they're doing, and they've been around a long time. This is six-year-old technology, off-the-shelf. It is ACPropulsion.com.

EVW: What do you get with the AC Propulsion unit?

JB: The AC Propulsion unit provides an air-cooled, 150-kilowatt, three-phase induction motor that they designed. That's a 100 pound unit. They also provide a 70 pound inverter, integrated charger, and their second generation unit is now bidirectional. It's a control unit, inverter/charger, for that electric motor drive. It is a really nice piece of technology. I can't say enough about how far ahead they are in producing very high-power, very high-performance electric drives.

EVW: How do you get to the 330 volts figure or so that you're specifying for this car? Is that a high or a low number for such efforts?

JB: [With respect to the] bus voltage for AC induction drives, I know that the Siemens Units is in the 600 range and the AC Propulsion is in the 400 range bus voltage, which is the upper end recharge voltage.

You know it has to be higher than the EMF of the battery pack so it'll drive current backwards through the battery. And then the batteries if they're all 12 volts and there are 28 of them, that's 336 but the Hawkers are 12.85 volts or something. That turned out to be about 360 volts.

AC induction drive at high voltage means fewer I squared R watts, the lower electrical dissipation, and so from an efficiency standpoint the higher the bus voltage the higher the pack voltage, the farther that your stored energy will go in your vehicle in terms of over-the-road-mileage. But it's more expensive and more of a safety issue the higher that voltage gets pushed.

EVW: I like the fact that your car is not so over-integrated that you can at least run it on all-electric if you choose to do so. A lot of the hybrid makers are not making their hybrids grid-chargeable and they are not making them so that you can run them on all electric if you choose to do so.

JB: Right, the genius of the AC Propulsion unit is that it is a high kilowatt rated recharging system that uses and reuses many of the same motor power components in the inverter controller during the recharge cycle. So it's not like you have a separate box full of expensive components that allow you to hook to the grid and recharge in an hour. Many other people could integrate grid recharging, but it would be a fairly slow going kind of thing.

The AC unit can operate at a fairly high rating, I think it's about 25 kilowatts, and that allows for extremely rapid recharging if you wish to see it. But they integrated and used many of the components over again, and that really led to some economies of packaging and investment in the system that in the long run should bring the -- what is really right now -- quite a high price of the unit, down to something that is worth the extra value added. So, once again, I must praise them for a great piece of technology.

EVW: I noticed that VW has been working with them and you've used a VW Diesel engine. Do you think VW could just duplicate some of the ground that you've covered and build a great hybrid vehicle, or is it just not that simple?

JB: Well let's put it this way, I think it's not that simple because they are not going after anywhere near the same application as we are. They're not trying to build a hybrid sports car with a mid-engine propulsion pack as we did.

But it is amazing to me that AC Propulsion is working so closely with them on, I forget if it's an Audi or a Volkswagen that they're trying to convert; they're using the AC unit and a diesel engine. OK, we kind of saw this coming, we did this, this was the natural choice. I don't know how they're going to control their parallel format power plant, but trust me, yeah, there is some work that we've done that they would find valuable.

To Part 2

Times Article Viewed: 14744
Published: 03-Mar-2002

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