GM FastLane: Checking Back In: Fuel Economy vs Fuel Efficiency

[Bruce Nunnally]

Editor's note: Last week, Dan Hancock, Vice President for GM Global Powertrain Engineering, posted about fuel economy vs fuel efficiency. We received a lot of great questions on the subject, so we thought we'd answer as many as we could from Dave Lancaster, GM Powertrain. -Alicia Dorset, blog editor

Joe: Also what ever happened to the 3 valve HV engines? The HVs already have a nice balance of power, efficiency, and cost. I'd like to see them continue to be improved.

Joe, Thanks for the comment. You have described the goal of the high value engines, balanced power efficiency and cost. Adding another intake valve improves breathing and top end power, but it has a negative impact on cost and introduces some unique problems with the combustion system. Right now, our high-feature V6 offers an alternative with all of the power and performance features available for a modern V6 engine.

Fred: I do have one question. And perhaps you can't answer it, or maybe you can. A few months ago, Ward's Auto released an article about a new DI V8 6.2 liter engine from GM. Even in prototype form, does this engine exist? Because based on what was said in the article. It is a revolutionary V8. And I applaud it.

Fred, While I can’t comment on future products, I can tell you that we showed a DI variant of our small block V8 to the press at our recent GM Powertrain technology show as an engine concept that we are evaluating. As you can see from the 2.0L turbo engine in the Pontiac Solstice GXP and Saturn Sky Red Line and the new DI version of the high feature V6 available in the Cadillac CTS and STS, we are beginning to roll-out this technology across our portfolio. Work on DI engines at GM dates back into the 1970’s, but it is only recently that the technology with electronic injection systems has made these engines practical for mass production.

http://fastlane.gmblogs.com/archives/2007/...g_back_i_1.html