|
Yes, one-cylinder motors are harsh. They usually have very large flywheels to help damp that out to some extent.
The three-cylinder Metro engines are not that bad. In large part because they are designed specifically to be three-cylinder engines, with combustion events equally spaced around the 720-degree four-stroke cycle.
If you take a four-cylinder engine (combustion events every 180 crank degrees) and just turn off one cylinder, you have three "hits" and one "miss", instead of three evenly-spaced "hits". This makes the motor run rougher and makes the vibrations harsher.
If you disable two opposite cylinders, you get alternating "hit" and "miss" events, which should be less vibration than the 3/4 engine.
The best candidates for cylinder deactivation are engines with a bunch of evenly-spaced cylinders, such as V6, V8, and V12 engines. You could shut down one bank of the motor and effectively make an I3, I4, or I6 engine. If the firing order is set up correctly in the first place, all combustion events will be evenly-spaced and not too far apart, and the engine will be reasonably smooth.
Honda has done the V6 single-bank deactivation. Several manufacturers have deactivated various parts of V8 motors, with varying levels of success.
-soD
|