AAARRRGGGGHHHH
Quote:
The Budack Cycle—as Jason Fenske from Engineering Explained mentions in his video—uses the same concept, except it closes the intake valve early. Thus, as the piston goes down with the valve closed, the pressure inside the combustion chamber drops, and then rises during the compression stroke. Ultimately—like in a Miller Cycle—this yields a lower effective compression ratio, which makes it easier for the power stroke to turn energy from combustion into downward motion of the piston. Like in the Miller Cycle, the increased efficiency comes at the detriment of power output
I hate these hacks...
The closure of the valve early (or late) traps a smaller volume of air/fuel in the cylinder at the commencement of ACTUAL compression, effectively lowering the swept volume...that's what limits the power.
The effective compression ratio yes, is lowered, but doesn't do what the article explains...lowering the effective compression ratio lowers efficiency.
However, allowing the trapped gasses to expand to a larger volume increases the efficiency, as more work can be gained.