GM's Power Train StrategyGM's Power Train Strategy

General Motors recently introduced a dual-mode hybrid for the Chevy Tahoe and the GMC Yukon. In addition, GM is developing a 4.5-l diesel V-8, the first light-duty V-8 clean diesel for North America. The Tahoe and Yukon will possibly have the diesel engine as an option, as well. This raises some interesting questions.

How do these two quite different power trains fit into GM's future?

We have an energy and propulsion strategy at General Motors and it's all centered around a path that eventually removes the vehicle from the energy and environmental debate. The intention is to get increasingly better fuel economy and reduce the emissions that are emitted by our power trains. We have a road map that gets us moving down that path that goes through the near term, the midterm and then eventually the long term.

The diesel engine is a critical part of that propulsion strategy. It is important to put it in context, though, because there is not a single 'silver bullet.' You might think of it that there is silver buck shot and it depends really on what your specific application is — what kind of a vehicle consumer/buyer you are and how you use the vehicle that best addresses what power train is the best option for you.

In the midterm, you start to introduce hybrid technologies and these technologies build upon the fact that you need to have an efficient heat engine to make the hybrid work. And so everything hybrid benefits from the foundation of a good internal combustion engine because that is what is powering the hybrid system.

Can you give some sort of time frame for the midterm?

You would have to say now we are into the midterm. We have been on this journey for years now and the interesting thing about this is all these technologies co-exist. So, as you move from what was the near term to the midterm, we are just getting into that now with the introduction of our new two-mode hybrid systems.

What role does the Chevy Volt play in this road map?

Using a true electric vehicle where the propulsion is through electric motors, it's just a matter of how do you get the electricity to power those electric motors. And it's through a combination of a plug-in recharge system and also some other supplementary power system. It could either be an internal combustion engine, which could be gas or diesel, or it could be an alternately fueled internal combustion engine or it could be a fuel cell.

What happens in the long term?

Long term the strategy leads us up to the fuel cell. The interesting thing is that if you look at all these technologies, they all start to dovetail together where one feeds into the other and provides the infrastructure that eventually builds into that next phase. So, this electrification of the vehicle is a basis that you need before you can make a hydrogen vehicle work. Because it is an electrically driven vehicle, it just uses a hydrogen fuel source through the fuel cell. All of these start to support each other in that way but we don't see the technologies going away in that time frame.

Is there a hybrid versus diesel debate in the future?

What's happening is different users will have different advantages from different technologies. So, some people might be quite well-satisfied with the future fuel cells, other people will be well-satisfied by having a diesel power train or a gasoline power train or perhaps an internal combustion engine with a hybrid system. GM's strategy is to satisfy all of those requirements.