Four-Stroke Engine Lubrication Apparatus Pressure Fluctuation
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Solution Overview
Problem
Conventional lubrication apparatuses for four-stroke engines face challenges in ensuring adequate lubrication around the crankshaft while preventing excessive oil mist from entering the valve operating chamber, leading to lubrication failures and oil consumption issues.
Innovation Solution
A lubrication apparatus that utilizes pressure fluctuations in the crank chamber to circulate oil between an oil reservoir and the crankshaft, and valve operating chamber, with controlled passageways and one-way valves to manage oil flow and prevent backflow, ensuring sufficient lubrication and minimizing oil residue in the valve operating chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil mist is supplied to both the crank chamber and valve operating chamber using the same concentration, then the valve operating devices receive adequate lubrication, but the crankshaft area does not receive sufficient lubrication
Solution Approach 1:
The patent divides the lubrication system into two separate pathways: one for liquid oil supply to the crank chamber and another for oil mist supply to the valve operating chamber. This segmentation allows different forms and concentrations of lubricant to be delivered to different areas, resolving the contradiction between adequate lubrication reliability and proper oil distribution quantity.
Solution Approach 2:
The patent applies different lubrication methods to different locations: liquid oil is supplied to the crank chamber where high lubrication reliability is needed, while oil mist is supplied to the valve operating chamber. This local differentiation of lubrication quality and concentration addresses the specific needs of each area, preventing both lubrication failure and excessive oil consumption.
2Reliability
If oil mist is oversupplied into the valve operating chamber, then valve operating devices are well-lubricated, but excessive oil remains in the chamber and is discharged with blowby gas
Solution Approach 1:
The patent changes the physical state parameter of the lubricant from liquid to mist form for the valve operating chamber. By supplying oil mist instead of liquid oil, the system achieves adequate lubrication while reducing the amount of oil that accumulates and is subsequently discharged with blowby gas, thus reducing oil consumption.
Solution Approach 2:
The patent supplies oil mist in controlled amounts to the valve operating chamber - enough to provide necessary lubrication but not excessive amounts that would lead to accumulation and discharge. This partial action approach prevents both lubrication failure and excessive oil consumption.
3Reliability
If a separate pump is provided for lubrication, then oil can be supplied reliably to all areas, but the engine weight increases
Solution Approach 1:
The patent employs a self-service lubrication system where the engine's own operational movements (piston reciprocation and crankshaft rotation) create the pressure fluctuations needed to circulate oil. The piston's reciprocating motion naturally draws liquid oil into the crank chamber, and the rotating crankshaft generates pressure fluctuations that distribute oil mist to the valve operating chamber, eliminating the need for external pumps and reducing engine weight.
Solution Approach 2:
The patent utilizes periodic pressure fluctuations generated by the piston's reciprocating motion and the crankshaft's rotation to drive oil circulation. These periodic actions naturally pump liquid oil into the crank chamber and generate pressure waves that distribute oil mist to the valve operating chamber, achieving reliable oil supply without mechanical pumps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively prevents lubrication failures around the crankshaft and reduces oil consumption by ensuring the right amount of oil is supplied to the crankshaft and valve operating chamber, while preventing excessive oil mist from entering the combustion chamber.
Implementation Method 1
supplying the oil to the crank chamber and a valve operating chamber accommodating the valve operating mechanism, using pressure fluctuation in the crank chamber, the pressure fluctuation being caused by reciprocating motion of a piston
Implementation Method 2
an oil feeding passageway configured to allow communication between the oil reservoir and the crank chamber when a negative pressure is created in the crank chamber to suck up the oil in the oil reservoir from the intake part and supply the oil to the crank chamber
Implementation Method 3
a communicating passageway configured to allow communication between the crank chamber and the oil reservoir when a positive pressure is created in the crank chamber and supply oil mist produced in the crank chamber to the oil reservoir
Data Source
AI summary
A lubrication apparatus for a four-stroke engine that prevents lubrication failure from occurring around the crankshaft and reliably prevents oil from remaining in a valve operating chamber includes: an intake part positioned below the level of an oil A in an oil reservoir even if the oil reservoir is tilted and the level of the oil A changes; an oil feeding passageway that sucks up the oil A from the intake part and supplies the oil A to the crank chamber; and an direct passageway that allows communication between a valve operating chamber and a crank chamber when a negative pressure is created in the crank chamber. Open end parts of the oil feeding passageway and the direct passageway which are open in the crank chamber are provided to open as the piston moves from a position near the top dead center to the top dead center.