About a year after the Silverado and Sierra Hybrids hit lots, GM's other 'green' engine will arrive for half-ton buyers – the 4.5-liter Duramax V8 diesel. It's sure to present buyers with an interesting dilemma. Which engine should they buy – gas, hybrid, or diesel?
If the decision is based strictly on fuel economy, then the hybrid will likely be the number one choice.
Mr. White and Bob Lutz, GM's vice chairman and product czar, both think the hybrid will achieve better overall fuel economy than the 4.5-liter diesel. Diesels are known to get about 20-percent better fuel economy than similar displacement gas engines. The decision will ultimately come down to buyers’ needs and how they intend to use the truck.
"It depends on what you're doing, because a light duty diesel will give you more capability, especially towing. So, for a pickup truck application, there’s room for both (powertrains)," says Mr. White, but he further explains, "You'd think diesel would be more appealing but some people are buying pickups just to commute in and not to work in. If someone has a pickup that's a commute vehicle and they use it on the weekend to pick up something at Home Depot, and they're only driving in town, then maybe the hybrid makes more sense."
Don't expect to see the Two-Mode Hybrid option appear for heavy duty truck owners. "It could work but I'm not sure how much duty cycle you'd get. If you're hauling heavy loads, diesels would be the right answer because people are working the truck hard a very high percentage of the time," says Mr. White.
And don't get hopes up for a diesel hybrid either. Mr. White explained that hybrids and diesels are independently expensive powertrains to produce. Combining the two would likely not yield high enough fuel economy improvements to make it economically worthwhile to offer a diesel-electric Two-Mode Hybrid truck.
So what comes after the Two-Mode Hybrid? It could eventually be a serial hybrid pickup, like the Chevy Volt or what entrepreneur Ian Wright proposes. But that's a long way off. According to Mr. Lutz, look for Four Mode Hybrids next, which will add extra modes to more efficiently run the truck in a wider array of driving conditions.