November 15, 2003 (Posted July 6, 2004)

GM Mild Hybrid Pickup, Transcription and Notes

GM Representative: I failed to get his name. He was helping present the vehicle outside.

Evworld: Josh Landess

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Josh: GM was using the lingo, “mild hybrid”, and then there is a higher level than that?

GM Representative: Yes. There’s 'mild', there’s 'medium' hybrid. I don’t know if the Toyota Prius is a fully integrated hybrid, to where there’s actually electric drive available. It launches on pure electric. Here, we don’t do that. Where it’s a mild hybrid, the engine basically provides all the propulsion.

Josh: Not even any battery for traction in any way?

GM Representative: Well this is a 5 (inaudible) engine. And it’s a 13 kW motor. So just like 15 horsepower. Doesn’t make any sense to use that for propulsion. (inaudible)

Josh: What about for regen braking?

GM Representative: We do regen braking. We cover as much as that, if we can.

Josh: Into what?

GM Representative: There is a 42 volt battery pack under the back seat. [Lead-Acid] There’s 3 12-volt batteries. Nothing cheaper than 12-volt batteries. And we’re easy on them, we don’t beat them up as hard as a starter motor does.

Josh: Well you know when I talked to Maxwell, they said that sometimes ultracaps can help extend the life of a [battery].

GM Representative: We were looking at ultracaps in the system about 2 years ago. The original design [...] had ultracaps in it. We started to look at the aspects of care and feeding of ultra caps. There’s some nasty chemicals in an ultracap, and in a fire they give out some pretty nasty fumes. Our battery pack is going to be in the passenger compartment. We decided that would not be a good idea. So we brought the design back from ultracaps.

There are advantages to ultra caps, no doubt about it.

Josh: I think they're incorporated into…. No, it’s not GM is it?

GM Representative: I don’t think there’s any American manufacturer that has ultracaps in their design.

Josh: The GE bus……?

GM Representative: There is a bus here with ultracaps in it....

Josh: Isn’t Alison transmission working with somebody to incorporate ultracaps?

GM Representative: The, Allison Bus? ... Nickel Metal Hybride batteries. No ultracaps.

Josh: That's what confused me.

GM Representative: It’s a pure.... what they call a parallel hybrid. Some of the other busses are what they call series hybrids. You generate electricity that way and drive the motor. If you can do the pure parallel hybrid it’s more efficient, because there are too many conversion losses in going from an engine to a generator to a motor. Or maybe even into a battery and then back out of a battery into a motor. So whatever makes sense, if you can do power from the engine to the wheels, [and] the engine’s operating in a sweet spot. That’s the best place to be. You can’t get any better than that.

Josh: Can you improve efficiency by going from the engine to the batteries and operating the engine optimally in the sweet spot all the time?

GM Representative: That's what the Alison bus does. That transmission was on display. ... It just looks like a big beefy transmission. There’s two 150 kilowatt electric motors inside that transmission. And they do exactly what you said. So when the engine can’t be in the sweet spot, you run the motors. And when the engine’s in a sweet spot you move as much propulsion of the wheel as you can and use the excess energy to bring the batteries back up.

Josh: I’ll have to study the literature it’s a little confusing.

GM Representative: To my way of thinking, that’s the best mechanization I’ve seen. And people have said that that’s what the Prius transmission should have been.

Josh: They seem to be getting good mileage one way or another.

GM Representative: Oh they do. They do. I don't mean to demean it.

Josh: The reason this caught my eye, and I felt that I had to ask you questions today, is that I haven’t seen any, any, hybrids on the road from GM yet. I know Saturn has something in the works for next year, I just wondered, I hadn't heard about this so I wanted to ask you about it.

GM Representative: It’s been talked about a little bit in the past year. It is productionized, and it is ready to go. It’s been validated, we ran vehicles on the dynos for 80,000 miles day and night.... It's basically a start and stop system. We’ll shut the engine off. We’ll just stop the vehicle. We’ll start it up again as soon as you [take your foot] off the brake.

Josh: Is this going to be a diesel model also?

GM Representative: There’s no reason it couldn’t be. I haven’t seen it in the build plan, but it’s basically an add-on system. So if there was a diesel there, there’s no reason why it couldn't be. You'd have to change some control algorithms.

Josh: The reason I asked about diesel is that I talk to a lot of biofuel advocates and anytime you can put a diesel in their hands, then they can go out and mess around with it .... and that allows flexibility for the people that I talk to. But we don’t know if Detroit has, aside from the bigger diesel engines, if they could ...

GM Representative: You know, they’re looking at it real carefully, especially with Isuzu, we have a venture with Isuzu, and they make a pretty good diesel. And Opel, we own outright, and they make a pretty good diesel. The smaller diesels are there.

Josh: We just have to wait to get the fuel?

GM Representative: Well that’s the big objection, is the pollution controls in the United States. Just against diesels in a big way. The public is still burned from when we tried to make the V-8s into diesels twenty years ago.