Piston-pin bearing lubrication system and method for a two-stroke internal combustion engine
First Claim
1. A system for lubricating normally abutting bearing surfaces between a piston pin and a small end journal of a connecting rod of an internal combustion engine in which the piston pin and the small end journal together provide a rotatable connection between a piston and its corresponding connecting rod, the system comprising:
- a source of lubricating oil being pumped under a first level of pressure;
communicating passages formed in a crankshaft and the connecting rod of the engine for delivering lubricating oil from the source to the abutting bearing surfaces;
an inertia pump installed within the connecting rod in communication with the communicating passages to provide a predetermined measure of lubricating oil between the abutting surfaces at a second pressure level that is higher than the first pressure level in reaction to the movement of the connecting rod wherein the pump has a first unbiased mass element which forces the predetermined measure of lubricating oil towards the pump outlet as the piston approaches bottom dead center portion of its stroke; and
a second unbiased mass element which moves from a first position, that allows oil to flow at the first pressure level from the source and through the pump to the normally abutting surfaces, to a second position, blocking the oil flow from the source thereby allowing the predetermined measure of oil forced by the first unbiased mass element to flow from the pump outlet.
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Abstract
An improved lubrication system and method for the normally contacting and abutting piston pin and connecting rod journal bearing surfaces of an internal combustion engine that includes an inertia pump in a connecting rod. The inertia pump reacts to the movement of the connecting rod and conveys a predetermined measure of lubricating oil at a high enough pressure to overcome the forces which cause the surfaces to normally maintain contact. By separating the normally contacting surfaces of the pin and the connecting rod journal, the surfaces become lubricated. Several embodiments of inertia pumps provide variations in implementing the invention.
4 Citations
16 Claims
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1. A system for lubricating normally abutting bearing surfaces between a piston pin and a small end journal of a connecting rod of an internal combustion engine in which the piston pin and the small end journal together provide a rotatable connection between a piston and its corresponding connecting rod, the system comprising:
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a source of lubricating oil being pumped under a first level of pressure; communicating passages formed in a crankshaft and the connecting rod of the engine for delivering lubricating oil from the source to the abutting bearing surfaces; an inertia pump installed within the connecting rod in communication with the communicating passages to provide a predetermined measure of lubricating oil between the abutting surfaces at a second pressure level that is higher than the first pressure level in reaction to the movement of the connecting rod wherein the pump has a first unbiased mass element which forces the predetermined measure of lubricating oil towards the pump outlet as the piston approaches bottom dead center portion of its stroke; and
a second unbiased mass element which moves from a first position, that allows oil to flow at the first pressure level from the source and through the pump to the normally abutting surfaces, to a second position, blocking the oil flow from the source thereby allowing the predetermined measure of oil forced by the first unbiased mass element to flow from the pump outlet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of lubricating normally contacting surfaces of a piston pin and a small end journal of a connecting rod of an internal combustion engine in which the piston pin and the small end journal together provide a connection between a piston and its corresponding connecting rod, the method comprising:
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providing a source of lubricating oil at a first level of pressure; providing a crankshaft and connecting rods of the engine with communicating passages for the delivery of lubricating oil from the source to the normally contacting surfaces; providing a pump within a connecting rod to be in communication with the communicating passages to receive the lubricating oil from the source and to inject a predetermined measure of lubricating oil at a second pressure level that is higher than the first pressure level between the normally contacting surfaces as the piston reaches bottom dead center portion of its stroke wherein the pump is provided a first unbiased mass element that forces the predetermined measure of lubricating oil towards the pump outlet as the piston reaches bottom dead center portion of its stroke and a second unbiased mass which moves from a first position that allows oil to flow at the first pressure level from the source and through the pump to the normally abutting surfaces to a second position in which the oil flow from the source is blocked and only the predetermined measure of oil forced by the first unbiased mass element is allowed to flow from the pump outlet;
the first unbiased mass element has a plunger mass portion and a plunger pump portion, the plunger mass portion has a greater diameter than the plunger pump portion, and the plunger mass portion has at least one longitudinal passage allowing flow of oil through the plunger mass portion. - View Dependent Claims (10, 11, 12, 13, 14)
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15. An inertia reactive pump for receiving liquid from a source at a relatively low pressure and for providing a predetermined measure of liquid to a pump outlet comprising:
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a plurality of freely movable mass elements which adapted to move in a plurality of longitudinal and axially-aligned bores within the pump in response to longitudinal inertia forces applied to the pump wherein; a first of the freely movable mass elements is a first unbiased mass element that forces the predetermined measure of lubricating oil in a first direction towards the pump outlet in response to inertia force being applied to the pump in a second direction opposite to the first direction wherein the first unbiased mass element has several longitudinally formed passages along a portion of its length; and a second of the freely movable mass elements is a second unbiased mass which moves from a first position that allows oil to flow at the low pressure from the source through the pump to the pump outlet to a second position in which the oil flow from the source is blocked. - View Dependent Claims (16)
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Specification