Patent ID: 8381692
Filing Date: 2013-02-26
Classification: F02B,Y10T

Abstract:
1. A compound internal combustion engine comprising: two main pistons paired to reciprocate up and down together within two main engine cylinders and coupled to a main rotating crank rotating continuously in a first direction, the main pistons having at least a compression phase and an exhaust phase; an auxiliary cylinder coupled to the two main cylinders having an intake receiving exhaust gases from at least one main engine cylinder during its exhaust phase, and with an auxiliary exhaust valve that opens when at least one main cylinder is in its compression phase; an auxiliary piston in said auxiliary cylinder and adapted to reciprocate within said auxiliary cylinder; and an auxiliary crank coupled to counter-rotate with respect to the main rotating crank, and rotating continuously in a second direction opposite to said first direction, and linkage means coupling said auxiliary piston with both said main and auxiliary crank such that when the downward stroke of the auxiliary corresponds to a crank angle exceeding 180 degrees for said main crank, and the upward stroke of the auxiliary piston corresponds to a crank angle below 180 degrees for said main crank, such that the auxiliary piston enjoys an asymmetric phase characteristic using a greater amount of main crank angle rotation for its downward stroke thus increasing the amount of power extracted from the exhaust gases from the two main cylinders.