Scotch yoke

This setup is most commonly used in control valve actuators in high-pressure oil and gas pipelines.

For example, the side rods of a locomotive may have scotch yokes to permit vertical motion of intermediate driving axles.

The higher percentage of time spent at top dead centre (dwell) improves theoretical engine efficiency of constant volume combustion cycles.

Experiments have shown that extended dwell time does not work well with constant volume combustion Otto cycle engines.

[4] Gains might be more apparent in internal combustion engines using a stratified direct injection (Diesel or similar) cycle to reduce heat losses.

Scotch yoke animation
Comparison of displacement and acceleration for a Scotch yoke compared with a crank and slider
Piston water pump, with a scotch yoke connection to its flywheel
Animation