Quote:
Originally Posted by redneck
After all, cylinder deactivation can help fuel economy.
|
This kind of cylinder deactivation is called DFCO ... engine braking.
That's cylinder deactivation on all cylinders.
Guess what, it slows you down.
The air does not expand because of the residual heat.
It expands because it's been compressed in the compression stroke - costing energy - and the piston is going down because it's connected to the crankshaft.
Sure you'll get some of that compression energy back, but never all of it.
Cylinder deactivation works if you can control the valves so the compression stroke is no longer a compression stroke, and very little energy is wasted moving the piston about.
There could be some advantage in increasing the load at the same rpm for the remaining cylinders - and better BSFC.
Don't expect miracles though ...