Cylinder Deactivation

One of the new technologies that’s come up in the current debate over fuel economy, Cylinder Deactivation isn’t really going to change much about the way passenger cars are built. It’s not a shift away from fossil fuels, or toward renewable energy sources, or even to a new kind of machinery, really; at best it’s a stopgap until ethanol, solar or fuel cell technology becomes economically viable. But it’s an ingenious short-term innovation that may have larger implications in the future, and that makes it worth a closer look.

Basically, the idea is that in a V6 or V8 engine, you don’t actually need all of the cylinders working when the vehicle is cruising down the highway or rolling down a hill. So you can equip the engine to detect these lower demand conditions and shut down some of the cylinders, leaving enough to provide power to maintain the forward rate of speed. Then, when the driver needs to accelerate or otherwise needs more power, the engine can reactivate the cylinders and restore full power. Here’s an AP News story, by way of Yahoo News, about how this all works. A similar technology is available that will actually shut off the engine while you are waiting for a light to change, and start it up again when you need to move.

The effect of these systems really isn’t all that impressive – the cylinder deactivation systems introduced by Honda for some of the 2005 and 2006 models show an improvement in gas mileage by about 4 or 5 miles to the gallon – about 12% to about 20%, depending on the vehicle. It certainly doesn’t compare to the dramatic increase in mileage offered by hybrid power systems, let alone fuel cell engines. But what makes this technology so interesting is that it should, at least in theory, be applicable to any type of engine, in any vehicle design, without the adoption of new fuel technologies, creation of new fuel production facilities, modification of gas stations or disposal problems involving huge banks of lead batteries. It isn’t even particularly expensive, especially when compared with hybrid systems (which can add $3,000 or more to the price tag, plus a dealer premium fee because the hybrid vehicles are so popular).

The other reason these are interesting is that they represent a perfect example of the business concept called Incremental Increase, or Incremental Improvement. The basic idea is that while making a single change in your business that increases your profits by 10% would be good, making five changes that each add 2% to your profits is just as good, and making five changes that each add 3% to your profits would be much better. In this case, perhaps the same cylinder deactivation technology could be used to produce cars that use 20% less E85 ethanol fuel, or the same concept could be used to extend the efficiency of electric motors or hybrid power systems. But even if the only thing that happens is that all of the larger vehicles sold from this point forward use 20% less fuel to travel the same distance, that’s still better than nothing.

And while that’s going on, maybe we can work on the next incremental increase…