Piston-pin bearing lubrication system and method for a two sroke internal combustion engine

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.

1 . A system for lubricating normally abutting bearing surfaces between a piston pin and the small end journal of a connecting rod of an internal combustion engine in which said piston pin and said small end journal together provide a rotatable connection between a piston and its corresponding connecting rod, comprising:
 a source of lubricating oil being pumped under a first level of pressure;   communicating passages formed in the crankshaft and connecting rods of said engine for delivering lubricating oil from said source to said abutting bearing surfaces;   a pump installed within a connecting rod in communication with said passages to receive said lubricating oil from said source;   wherein said pump provides a predetermined measure of lubricating oil between said abutting surfaces as said piston reaches bottom dead center portion of its stroke cycle.   
   
   
       2 . A system as in  claim 1 , wherein said pump reacts to the movement of the connecting rod in which it is installed to provide said predetermined measure of lubricating oil between said normally abutting surfaces as said piston reaches bottom dead center portion of its stroke cycle. 
   
   
       3 . A system as in  claim 2 , wherein said pump contains elements which are movable in directions parallel to the longitudinal inertia forces created in said connecting rod during the stroke cycle. 
   
   
       4 . A system as in  claim 3 , wherein said pump contains valving elements which remain open to allow oil to flow from said source and through said pump to said normally abutting surfaces at a first pressure level that is a function of the source pressure and the resistance presented by said passages and the valves over other portions of the stroke cycle. 
   
   
       5 . A system as in  claim 4 , wherein said pump valving elements are closed when deceleration forces reach a predetermined level as said piston reaches the bottom dead center portion in the stroke cycle and said movable elements force said predetermined measure of oil to be injected between said abutting surfaces at a second pressure level that is higher than said first pressure level. 
   
   
       6 . A system as in  claim 5 , wherein said second pressure level is sufficient to cause temporary separation between said normally abutting surfaces and to allow lubricating oil to be distributed therebetween. 
   
   
       7 . A system as in  claim 2 , wherein said pump contains an unbiased reciprocating plunger element within a bore that is oriented within said connecting rod to allow movement of said plunger along its longitudinal axis within said bore and such movement is an inertia reaction to acceleration and deceleration forces generated by the reciprocating movement of the piston during its stroke cycle and communicated into said connecting rod. 
   
   
       8 . A system as in  claim 7 , wherein said pump further contains valving elements which remain open to allow oil to flow from said source and through said pump to said normally abutting surfaces over other portions of the stroke cycle at a first pressure level that is a function of the source pressure and the resistance presented by said passages and the valves. 
   
   
       9 . A system as in  claim 8 , wherein said plunger element serves as a valving element over other portions of said stroke cycle. 
   
   
       10 . A system as in  claim 9 , wherein said plunger element is a two stage mass, including a first stage portion that slides within a first portion of said bore and contains several longitudinally formed passages to allow oil to flow therethough when said plunger element moves within said bore; and
 a second stage portion that slides within a second portion of said bore to provide the injection of a predetermined measure of lubricating oil from said second portion of said bore out of said pump and between said normally abutting surfaces.   
   
   
       11 . A method of lubricating normally contacting surfaces of a piston pin and the small end journal of a connecting rod of an internal combustion engine in which said piston pin and said small end journal together provide a connection between a piston and its corresponding connecting rod, comprising the steps of:
 providing a source of lubricating oil at a first level of pressure;   providing the crankshaft and connecting rods of said engine with communicating passages for the delivery of lubricating oil from said source to said normally contacting surfaces;   providing a pump within a connecting rod to be in communication with said communicating passages to receive said lubricating oil from said source; and   injecting a predetermined measure of lubricating oil between said normally contacting surfaces as said piston reaches bottom dead center portion of its stroke cycle.   
   
   
       12 . The method of  claim 10 , wherein said pump is provided to react to the movement of its associated connecting rod to provide said predetermined measure of lubricating oil between said normally contacting surfaces as said piston reaches bottom dead center portion of its stroke cycle. 
   
   
       13 . The method of  claim 12 , wherein said pump is provided to contain elements which are movable in directions parallel to the longitudinal inertia forces created in said connecting rod during the stroke cycle. 
   
   
       14 . The method of  claim 13 , wherein said pump is provided to contain valving elements which remain open to allow oil to flow from said source and through said pump to said normally contacting surfaces at a first pressure level over other portions of the stroke cycle; and
 said first pressure level being a function of the source pressure and the resistance presented by said passages and valving elements.   
   
   
       15 . The method of  claim 14 , wherein said pump valving elements are closed when deceleration forces reach a predetermined level as said piston reaches the bottom dead center portion in the stroke cycle and said movable elements inject said predetermined measure of oil between said contacting surfaces at a second pressure level that is higher than said first pressure level. 
   
   
       16 . The method of  claim 15 , wherein said second pressure level is sufficient to cause temporary separation between said normally contacting surfaces and to allow lubricating oil to be distributed therebetween. 
   
   
       17 . The method of  claim 12 , wherein said pump is provided to contain an unbiased reciprocating plunger element within a bore that is oriented within said connecting rod to allow movement of said plunger along its longitudinal axis within said bore and such movement is an inertia reaction to acceleration and deceleration forces generated by the reciprocating movement of the piston during its stroke cycle and communicated into said connecting rod. 
   
   
       18 . The method of  claim 17 , wherein said pump is provided to contain valving elements which remain open to allow oil to flow from said source and through said pump to said normally contacting surfaces at a first pressure level that is determined by the source pressure and the resistance presented by said passages and valving elements over other portions of the stroke cycle. 
   
   
       19 . The method of  claim 18 , wherein said plunger element is provided to serve as a valving element over other portions of said stroke cycle. 
   
   
       20 . The method of  claim 19 , wherein said plunger element is provided as a two stage mass, including a first stage portion that slides within a first portion of said bore and contains several longitudinally formed passages to allow oil to flow therethough when said plunger element moves within said bore; and
 a second stage portion that slides within a second portion of said bore to provide the injection of a predetermined measure of lubricating oil from said second portion of said bore out of said pump and between said normally contacting surfaces.