Rosario repeatedly describes the GM system as "elegant" and enjoys drawing a line under the fact that it works best with the firm's pushrod engines, which he rightly says come in for a lot of abuse from the media for being old-world technology.
"Other manufacturers have been praised for increased kinematic complexity," Rosario says, "but we've been going the other way and we've been polishing the engine. We're using the resources available and saving money."
As a result, "the shareholders and the public will gain since it would cost US$3 - 4 billion to develop a new engine; this system will allow GM to keep this engine going even longer."
As for the public, they can look for a range of fuel economy gains, depending upon how they drive. Rosario says it is 5 to 8 per cent on the government test cycle, but the more urban driving the bigger the savings. A gain of more than 10 per cent would not be impossible, he says.
Right now, the cylinder deactivation system is only going to be included in GM's 4.8-, 5.3- and 6-litre V8s, but Rosario says the company is considering other applications. "On a cost-effective analysis," he says, "any variable displacement engine would be great."