General Motors is interested in expanding the capabilities of its non-diesel Heavy Duty powertrain lineup, including a more powerful gas V-8 and potentially offering an engine prepped to run on either gasoline or propane.
Increasingly tougher diesel emissions regulations are forcing the consideration.
In 2007, GM and other HD pickup truck manufacturers added diesel particulate filters to meet tougher EPA rules that mandated cutting soot emissions by 90 percent from 2006 levels. The new hardware can cost more than $1,000 and requires up to seven-tenths of a gallon of diesel to incinerate trapped soot so it won't pollute the environment.
As of Jan. 1, GM's new 2011 Heavy Duty pickups (and Ford's 2011 Super Duty pickups) will use selective catalytic reduction, or SCR, and a new high-capacity two-stage exhaust gas recirculation system to reduce nitrogen oxide emissions by 90 percent from 2007 levels. SCR uses diesel exhaust fluid, or DEF, that costs about $2.69 a gallon and can be purchased in a canister or at a DEF pump next to diesel fuel.
"We have to have a viable alternative to diesel," said Jeff Luke, GM's chief engineer for full-size pickups. "When you think about diesel and escalating emissions controls, the diesel option could become cost prohibitive for some customers that they are going to look for other alternatives."
One place to start would be the 360-horsepower, 380 pounds-feet of torque 6.0-liter V-8 gas engine that's already available for GM HD pickups.
"We're looking at upping the power and performance in the future of the 6.0-liter V-8," Luke said.
GM is also facing increased competition in gas engines from Ford's new 6.2-liter V-8 and a new 6.4-liter Hemi V-8 engine from Chrysler that's expected in 2012.
Another powertrain option would be clean-burning, low-cost compressed natural gas or liquid propane. GM stopped offering CNG as a factory option for its HD pickups in 2006.
"We're also looking at CNG and LPG," Luke said. "It probably wouldn't be at the factory but a second-stage upfit [at a third-party facility] that would add a tank and lines. We're considering a bifuel version that could run on gas and propane."
But for customers who need the most capability and the best fuel economy while towing, Luke said diesel engines, like the Duramax, will still remain the ideal choice.