Four stroke internal combustion engine with inlet air compression chamber

An internal combustion engine with gas compressing crankcase, comprising:

• a substantially sealed crankcase;
• a cylinder, the cylinder comprising a sidewall extending outward from the crankcase to an upper end portion, the cylinder further comprising, adjacent the upper end portion, a head, the head further comprising an inlet defined by inlet aperture walls and an outlet defined by outlet aperture walls;
• an intake valve, said intake valve operably disposed adjacent said inlet;
• an exhaust valve, said exhaust valve operably disposed adjacent said outlet;
• a piston, the piston slidably mounted in the cylinder, forming an upper compressible chamber within the cylinder between the piston and the head;
• a crankshaft rotatably mounted in the substantially sealed crankcase;
• a connecting rod operatively mounted for translation of rotary motion of the crankshaft into reciprocal motion of the piston;
• an air inlet line, said inlet air line further comprising an inlet only valve;
• an inlet air compression chamber, the inlet air compression chamber fluidically disposed between the substantially sealed crankcase and the inlet only valve, said inlet air compression chamber comprising (a) a crankcase side interior sidewall and an inlet air side interior sidewall, and (b) a flexible membrane sealingly affixed between the crankcase side interior sidewall and the inlet air side interior sidewall for motion cyclically toward and away from each of the crankcase side interior sidewall and the inlet air side interior sidewall;
• an intake air outlet line, said intake air outlet line further comprising an outlet only valve;
• an intake air plenum, said intake air plenum having a plenum inlet adjacent said outlet only valve and a plenum outlet adjacent the inlet of the head;
• wherein movement of the piston away from the head compresses gas within said substantially sealed crankcase against the flexible membrane, the flexible membrane responsively compressing inlet air within said inlet air compression chamber, whereupon said outlet only valve opens, allowing compressed inlet air to escape into said intake air plenum.

A process of operation of a four-stroke internal combustion engine, said process comprising:

• providing an inlet air compression chamber located between an air inlet and a sealed crankcase, said air inlet having an inlet only valve adjacent the inlet air compression chamber, and wherein said inlet air compression chamber comprises an inlet air side and a crankcase side with a displaceable member secured therebetween, and wherein the displaceable member is passively responsive to differential pressure between said sealed crankcase and said inlet air side of said inlet air compression chamber;
• compressing air in said inlet air compression chamber during a down stroke of a piston;
• discharging said compressed inlet air from the inlet air compression chamber through an outlet only valve;
• adding fuel to said compressed inlet air to form a compressed air/fuel mixture;
• injecting compressed air/fuel mixture into said cylinder;
• further compressing said compressed inlet air/fuel mixture in response to upward movement of said piston, to provide a combustible fuel/air mixture;
• igniting said combustible fuel/air mixture;
• timing said engine for four stroke cycle operation.