The original purpose of quench, as described in the patent application, is knock suppression. It does this by creating a layer of charge (generally opposite the plug location) thin enough that shock wave-induced ignition (not the expanding kernel from the spark plug) cannot occur: the mixture burns slower than it loses heat to the *matching head and dome surfaces.

It does other things too; squish occurs whenever 2 surfaces (they need not be parallel, flat, or horizontal) approach each other and the charge between them is ejected into the larger chamber volume, regardless of the final separation distance.

BTW: the genesis of using a heat sink* to prevent combustion is even older: the 19th century Sir Humphrey Davies mine safety lamp, in which a wire mesh cage surrounds the illumination flame. Any flammable vapor in the atmosphere catches fire inside the screen, but is extinguished by heat loss to the mesh and cannot blow up the miners.