Even Stephens: GM powertain czar Tom Stephens' three hybrid strategy evens the score with Honda, Toyota and Ford

Automotive Industries,  Feb, 2003  

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At the 2003 North American International Auto Show in Detroit, GM dropped a bomb on environmental skeptics by announcing that it would field three hybrid gas/electric powertrains beginning in 2004. The systems will be offered in volumes of up to one million units annually if customer demand requires. GM said it expects at least 7,000 hybrid SUVs will be sold in the first year, making good on its promise to target low mileage/high volume vehicles to achieve maximum environmental benefit.

Al editor Gerry Kobe spoke with Tom Stephens, GM's group vice president of powertrains about the specifics of GM's decision.

Q. After being criticized for not having hybrid technology, what prompted GM to introduce not one but three hybrid systems?

A. Hybrids are a bridge to our long-term strategy, which is fuel cells. And naturally you want to get the cost down for that strategy. So the first thing you want to do is break that long-term plan into its major systems. Then you want to figure out what you need to learn on those major systems to get cost out of the design as well as manufacturing the components so you can get the cost out of the process.

Q. How much do hybrids and fuel cell vehicles actually share?

A. If you look at the fuel cell, obviously you have to do all those things on the fuel cell stack by itself, but what about the electric motors that are in there? What about the electronics that make it all work together? Well, you can pick all of that knowledge up on a hybrid. So we decided to start working on the hybrid, knowing that it will in fact help bridge us to the fuel cell strategy. You still have the rest to do but it's a nice start.

Q. So are the hybrids a good value in and of themselves or are they just a stepping stone to fuel cell vehicles?

A. GM's hybrids will be very effective. Some of the technologies we have, like displacement on demand (DOD), is ideal to mate up with a flywheel alternator system. Any hybrid powertrain tends to improve the city mileage more than the highway economy, but DOD tends to improve highway better than city. You put them together and all of a sudden its like a super position, you have great city and highway.

Q. How is that different from other hybrids like those from Honda and Toyota?

A. If you look at all hybrids out there today, especially the Toyota hybrids, all of them are designed for congested stop and go driving. And I think you can read that to be Tokyo. And they do a good job for that kind of driving. But if you look at America, we only drive 40 percent of the time in city traffic, the rest is highway driving. So it would be better to have a system that improves both city and highway and we have done that. So its really an American solution.

Q: Having driven the Japanese hybrids I'm not sure U.S. drivers will embrace the lower power output of these vehicles. Have you found a way around that?

A: Again, that is where DOD comes in. Americans like the power they get now. They still like to put their families in the truck. They like to get groceries. They like to pull their boat and with DOD, the power is there when you need it and off when you don't It's a no compromise American solution. Doesn't compromise performance in any way and you've got utility. So we don't just have a hybrid system, we have a hybrid system designed for the way we drive in the U.S. That's why we feel it is a good bridging strategy toward our long-term solution, which is fuel cells.

Q: Why three approaches to hybrids? Why not just one?

A: We have a mid-, near- and long-term strategy. The companies that have already done hybrids have taken a small slice or a sliver of the market. We chose not to do that. We thought, why don't we try to look at the entire portfolio of the market and do it by choosing three of our highest volume architectures. The first is our full-size truck and that is our highest volume going. That volume gives it a lot of leverage and that is why we are introducing it later this year to commercial fleets and then later to retail, two pickups, the Silverado and Sierra with a hybrid option that improves economy 10 to 12 percent. By the way, we are going to follow that in 2007 with this displacement on demand technology and take the 10 to 12 percent to 15 to 20 percent from today's level.

Q: What other platforms did you choose for hybrids?

A: Next was Theta architectures, mid-size SUVs like the Saturn VUE or new Chevy Equinox and after that we will do the mid-size platform called Epsilon. We will do the Malibu first and then others to follow.

Q: And each will take a different approach?

A: We will have three levels of hybridization. Everything from the flywheel alternator on the truck to the belt alternator starter that will go on some of the small AND cars and small intermediate cars as well as well as AND sport/utility vehicles. And then we have another one that is a dual electric motor system that has twin electric motors that control a 6-speed manual transmission and shifts automatically. That system will be on a mid-size SUV like the VUE and can improve mileage by 50 percent.