Split cylinder engine and method of operation

Claim 1

A two-stroke cycle split cylinder internal combustion engine comprising a cylinder block having a pair of adjacent cylinders consisting of an induction cylinder and a power cylinder, a cylinder head closing adjacent ends of said cylinders and having an inlet port to said induction cylinder, an exhaust port from said power cylinder and a transfer passage between said cylinders, pistons in said cylinders and arranged for reciprocation in predetermined timed relation, with the piston of said induction cylinder leading the piston of said power cylinder by less than one stroke, said cylinder head mounting an inlet valve closing said inlet port and operable to admit an inlet charge to said induction cylinder, an exhaust valve closing said exhaust port and openable to allow escape of gases from said power cylinder and a transfer valve closing said transfer passage intermediate said induction and power cylinders and openable to permit the flow of gases from said induction cylinder to said power cylinder, and spark ignition means in a portion of said transfer passage between said transfer valve and said power cylinder and closely adjacent said transfer valve, such portion of said transfer passage forming a recessed initial combustion chamber open to said power cylinder, said exhaust valve being actuated in timed relation to said engine pistons and being arranged to close sufficiently early in the compression stroke of the power piston to trap a relatively large volume of burned gases in said power cylinder for mixture with and dilution of part of the fresh gases transferred from said induction cylinder for combustion in said transfer passage and said power cylinder.

Claim 8

The method of operating an internal combustion engine having induction and power expansible chambers connected by a transfer passage forming a recessed initial combustion chamber for said power chamber, said method comprising repetitively performing an operating cycle including the steps of: a. drawing a charge of air into said induction chamber by expansion thereof, b. partially compressing said air charge in said induction chamber by contraction thereof, c. transferring said air charge to said transfer passage and therethrough to said power chamber for mixture with retained burned gases from the previous cycle, d. further compressing said air charge through contraction of said power chamber, e. mixing fuel with said air charge to form a compressed combustible mixture, f. igniting said combustible mixture in said transfer passage for burning in said transfer passage and subsequently in said power chamber, g. expanding the burning and burned gases in said power chamber by expansion thereof with an output of useful work, h. exhausting a major portion of the burned gases from said power chamber by blowdown through exhaust port means, i. retaining a relatively large portion of the burned gases in said expansion chamber for recompression and mixing with the fresh charge to be supplied to said power chamber for burning on the subsequent cycle.

Claim 9

The method of operating an internal combustion engine having induction and power expansible chambers connected by a transfer passage forming a recessed initial combustion chamber for said power chamber, said method comprising repetitively performing an operating cycle including the steps of: a. drawing a charge of air into said induction chamber by expansion thereof, b. partially compressing said air charge in said induction chamber by contraction thereof, c. transferring said air charge to said transfer passage and therethrough to said power chamber for mixture with retained burned gases from the previous cycle, d. further compressing said air charge through contraction of said power chamber, e. mixing fuel with said air charge to form a compressed combustible mixture, f. igniting said combustible mixture in said transfer passage for burning in said transfer passage and subsequently in said power chamber, g. expanding the burning and burned gases in said power chamber by expansion thereof with an output of useful work, h. exhausting a major portion of the burned gases from said power chamber by blowdown through exhaust port means, i. retaining a relatively large portion of the burned gases in said expansion chamber for recompression and mixing with the fresh charge to be supplied to said power chamber for burning on the subsequent cycle.