US 7,481,189 B2 · Internal combustion engine and method

Abstract

Internal combustion engine and method with compression and expansion chambers of variable volume, a combustion chamber, a variable intake valve for controlling air intake to the compression chamber, a variable outlet valve for controlling communication between the compression chamber and the combustion chamber, means for introducing fuel into the combustion chamber to form a mixture of fuel and air which burns and expands in the combustion chamber, a variable inlet valve for controlling communication between the combustion chamber and the expansion chamber, a variable exhaust valve for controlling exhaust flow from the expansion chamber, means for monitoring temperature and pressure conditions, and a computer responsive to the temperature and pressure conditions for controlling opening and closing of the valves and introduction of fuel into to the combustion chamber to optimize engine efficiency over a wide range of engine load conditions. The relative volumes of the compression and expansion chambers and the timing of the valves are such that the pressure in the combustion chamber remains substantially constant throughout the operating cycle of the engine, and exhaust pressures are very close to atmospheric pressure regardless of the load on the engine. The engine runs so quietly and burns so cleanly that in some applications it may not require a muffler and/or a catalytic converter.

Claims33

Dependent claims

An internal combustion engine, comprising:

a compression cylinder, an expansion cylinder, a piston in each of the cylinders, a crankshaft interconnecting the pistons for reciprocating movement between top and bottom dead center positions in the cylinders, a combustion chamber, a variable intake valve for controlling air intake to the compression cylinder, a variable outlet valve for controlling communication between the compression cylinder and the combustion chamber, means for introducing fuel into the combustion chamber where the fuel mixes with air from the compression cylinder to form a mixture which burns in the combustion chamber, a variable inlet valve for controlling communication between the combustion chamber and the expansion cylinder, and a variable exhaust valve for controlling exhaust flow from the expansion cylinder.

An internal combustion engine, comprising:

a compression cylinder;
a compression piston in the compression cylinder;
an expansion cylinder;
an expansion piston in the expansion cylinder;
a crankshaft interconnecting the pistons for upstroke and downstroke movement between top and bottom dead center positions in the cylinders;
a combustion chamber;
an intake valve which opens when the compression piston is past top dead center and remains open during a portion of the downstroke of the compression piston to admit air to the compression cylinder;
an outlet valve which remains closed during a first portion of the upstroke of the compression piston as the air is compressed in the compression cylinder, opens during a second portion of the upstroke to pass the compressed air to the combustion chamber, and closes when the compression piston is at or near top dead center;
means for introducing fuel into the combustion chamber where the fuel mixes with the air from the compression cylinder to form a mixture which burns in the combustion chamber;
an inlet valve which opens when the expansion piston is at or near top dead center and remains open during the first portion of the downstroke of the pistons to allow gas from the combustion chamber to expand into the expansion cylinder and drive the expansion piston in a downward direction;
an exhaust valve which is open during the upstroke of the pistons to allow exhaust gas to be expelled from the expansion cylinder and closes when the expansion piston reaches top dead center, and a computer for controlling operation of the valves and introduction of fuel into to the combustion chamber.

8 more elements

A method of operating an internal combustion engine having compression and expansion cylinders of equal volume, a combustion chamber, and compression and expansion pistons connected to a crankshaft for reciprocating movement between top and bottom dead center positions in respective ones of the cylinders, with each of the pistons making one upstroke and one downstroke during each revolution of the crankshaft, the steps of:

opening an intake valve when the compression piston is past its top dead center position, keeping the intake valve open for approximately 100/X percent of the downstroke of the compression piston, where X is the volume of gas leaving the combustion chamber divided by the volume of air entering the combustion chamber, drawing air into the compression cylinder during the downstroke of the compression piston, closing the intake valve when a desired amount of air has been drawn into the compression cylinder, compressing the air in the compression cylinder during a first portion of the upstroke of the compression piston, opening an outlet valve when the pressure in the compression cylinder is at or near the pressure in the combustion chamber, pushing the compressed air out of the compression cylinder through the open outlet valve and into the combustion chamber during a second portion of the upstroke of the compression piston, closing the outlet valve when the compression piston reaches its top dead center position, introducing fuel into the combustion chamber, mixing the fuel with the air from the compression cylinder in the combustion chamber to form a mixture which burns in the combustion chamber, opening an inlet valve when the expansion piston is in its top dead center position, allowing gas from the combustion chamber to expand into the expansion cylinder and drive the expansion piston in a downward direction, closing the inlet valve when the amount of gas entering the expansion cylinder is equal to the amount of air supplied by the compression cylinder plus the amount of gas expansion occurring in the combustion chamber, opening an exhaust valve when the pressure in the expansion cylinder is substantially equal to atmospheric pressure, pushing exhaust gas out of the expansion cylinder through the open exhaust valve with the expansion piston, and closing the exhaust valve when the expansion piston is at or near its top dead center position.

Dependencies are inferred from the claim text.

Internal combustion engine and method

Life of this patent

Internal combustion engine and method

Life of this patent

Abstract

Claims33