This week the Super Chevy guys in the office tooled around in a GM press vehicle. They received a 2009 Chevy Tahoe Hybrid. Luckily, I was able to take it home a few nights and evaluate the Hybrid technology firsthand. I am impressed. The Tahoe, despite its girth, was knocking down 20 mpg!
As amazing feat as that is, all of those efficient miles per gallon cannot be strictly credited to the Hybrid drive, which kicks off at around 31 mph, depending on driving situation. Once the engine turns on, GM has an awesome fuel saving computer strategy called DOD. It stands for Displacement On Demand and applies as little cylinders that are required for that moment. Getting on the highway the engine operates as a standard V8 mill. As you cruise and have very little throttle applied, the computer shuts things down and operates only four cylinders, to save fuel.
We have seen DOD on not just the Tahoe Hybrid ,but also on conventional-powered V8 vehicles such as the Pontiac G8 and various GM light-duty trucks. If you want to get real accurate with history, GM put DOD into Cadillac Eldorado cars in 1983-1985 (if I remember correctly). That was a disaster because the Bosch eprom chips failed and the DOD didn't work as it should. People started ripping out that option and letting the cars operate strictly on eight cylinders.
Today, the DOD concept works flawlessly in the trucks and G8 applications. Why can't Ford come to market with a similar concept? My '07 Stang knocks off 24 mpg and is only mildly modified. That pails in comparison to a G8 in the office that gets 26-28 mpg. The kicker is that the G8 is some 400 pounds heavier! Imagine my little Three-Valve engine with DOD, I would guess near 30 mpg is possible.
Driving the Eco-friendly Tahoe got me thinking, could an aftermarket company come up with conversion kits to make other engines operate with DOD? According to the GM High Tech Performance magazine guys in the office, there are some mechanical parts inside certain LS engines that allow the extra cylinders to be shutdown during light throttle activity. That would have to be done to the Ford engines in order to do it. Otherwise, an aftermarket EFI system could be used with a software upgrade to make it happen.
If Ford could somehow apply DOD to its current line of engines, it would make the cars more fuel efficient friendly and help keep production V8 cars in dealerships and on the streets. With rumors circulating of GM and Ford opening dialog in working together on powertrain components, DOD could be a part of Ford's engines line up sooner than we think.