continuous-expansion engine

[ kuh n-tin-yoo-uh s-ik-span-shuh n ]
/ kənˈtɪn yu əs ɪkˈspæn ʃən /

noun

a steam engine in which a high-pressure cylinder is partly exhausted into a low-pressure cylinder during each stroke.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019