Abstract: The invention relates to a multiple-cycle internal combustion engine having as a unit of two 4-cycle cylinders operating 180.degree. apart and one 2-cycle cylinder firing 90.degree. after the 4-cycle cylinders fire. The 4-cycle exhaust is admitted to the intake port of the 2-cycle cylinder and the 2-cycle cylinder ports are opened and closed in correlation with the exhaust cycle of the 4-cycle cylinders so that 4-cycle exhaust is admitted to the 2-cycle cylinder and passes out through the outlet port thereof sweeping 2-cycle exhaust out along with it. Thus, advantages are taken of the uncombusted products in the 4-cycle exhaust to drive the 2-cycle cylinders. At the same time, advantage is taken of the higher efficiency of 4-cycle cylinders at low speeds and the higher efficiency of 2-cycle cylinders at high speeds to obtain an over all improvement in the efficiency of the engine.

Abstract: The invention relates to a multiple-cycle internal combustion engine having as a unit of two four-cycle cylinders operating 180.degree. apart and one two-cycle cylinder firing 90.degree. after the four-cycle cylinders fire. The four-cycle exhaust is admitted to the intake port of the two-cycle cylinder and the two-cycle cylinder ports are opened and closed in correlation with the exhaust cycle of the four-cycle cylinders so that four-cycle exhaust is admitted to the two-cycle cylinder and passes out through the outlet port thereof sweeping two-cycle exhaust out along with it. Thus, advantages are taken of the uncombusted products in the four-cycle exhaust to drive the two-cycle cylinders. At the same time, advantage is taken of the higher efficiency of four-cycle cylinders at low speeds and the higher efficiency of two-cycle cyclinders at high speeds to obtain an over all improvement in the efficiency of the engine.