Engine Piston Pin-Joint Lubrication With Pooling Cavities for Flow Stability
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Solution Overview
Problem
Existing lubrication systems for pin joints in opposed-piston engines are inefficient in delivering lubricant, leading to potential scuffing and seizure due to inadequate lubrication, especially in 2-stroke engines where lubricant flow reversal occurs, affecting hydrodynamic lubrication.
Innovation Solution
A lubrication system with a piston pooling cavity and journal pooling cavity that holds a larger volume of lubricant than traditional systems, combined with a check valve to prevent reverse flow, ensuring consistent lubricant delivery to the pin joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional lubrication system is used in opposed-piston engines, then the system structure is simple, but the lubricant delivery is insufficient leading to scuffing and seizure
Solution Approach 1:
The pooling cavity stores lubricant in advance before it is needed, creating a reservoir that ensures lubricant availability during critical operating phases. The cavity accumulates lubricant delivered by cooling galleries and nozzles, preparing it for subsequent delivery to the pin joint through lubrication passages, thereby preventing lubrication failure during high-demand periods
Solution Approach 2:
The pooling cavity acts as an intermediary component between the lubricant delivery system (cooling galleries and nozzles) and the pin joint. It receives, stores, and regulates lubricant flow, mediating the transfer of lubricant from the cooling system to the journal aperture and ensuring consistent supply to the pin joint regardless of fluctuating engine conditions
2Reliability
If lubricant flow rate is increased to prevent scuffing, then lubrication reliability improves, but lubricant waste increases
Solution Approach 1:
The system uses partial action by delivering lubricant selectively - storing it in the pooling cavity during periods when less lubrication is needed, and then utilizing stored lubricant during critical phases. This avoids continuous excessive lubricant flow, reducing waste while ensuring adequate lubrication when required
Solution Approach 2:
The pooling cavity system changes the temporal distribution parameter of lubricant flow - transforming a potentially continuous high-rate flow into a regulated flow pattern with storage and release phases. This parameter change allows the system to maintain reliability while reducing overall lubricant consumption
3Reliability
If lubricant flow is increased to maintain hydrodynamic regime, then pin joint protection improves, but flow reversal problems worsen in 2-stroke engines
Solution Approach 1:
The pooling cavity provides beforehand cushioning by storing lubricant in advance, creating a buffer that cushions against flow reversal. When reverse flow occurs in 2-stroke engines, the stored lubricant in the cavity maintains forward pressure and prevents complete flow reversal, ensuring continuous hydrodynamic lubrication
Solution Approach 2:
The system converts the potential harm of flow reversal into a benefit by using the pooling cavity to trap and redirect reverse flow. Lubricant that might otherwise flow backward is captured in the cavity and redirected forward through the lubrication passages, transforming the harmful reverse flow into useful lubrication delivery
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 system maintains a stable lubricant flow rate under varying engine conditions, preventing scuffing and seizure, and operates in a hydrodynamic regime, enhancing the performance and reliability of the pin joint.
Implementation Method 1
a piston cooling gallery and a piston lubrication passage in fluid communication with the piston cooling gallery and the piston pooling cavity
Implementation Method 2
The connecting rod can be fluidly coupled to the pin bore by a check valve
Implementation Method 3
A lubrication system with a piston pooling cavity and journal pooling cavity that holds a larger volume of lubricant than traditional systems
Data Source
AI summary
Systems and apparatuses include a lubrication system having an engine piston defining a gudgeon pin aperture, a piston pooling cavity extending radially outward from the gudgeon pin aperture, a piston cooling gallery, and a piston lubrication passage. The piston lubrication passage is in fluid communication with the piston cooling gallery and the piston pooling cavity. The piston further includes a pin journal received in the gudgeon pin aperture of the engine piston and defining a journal aperture in fluid communication with the piston pooling cavity and a journal pooling cavity in fluid communication with the journal aperture. A gudgeon pin is received within the gudgeon pin aperture adjacent the pin journal, which provides fluid communication between the journal pooling cavity and the gudgeon pin.