Engine Oil Passage Design for Balancer Shaft Lubrication
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Solution Overview
Problem
The existing lubricating structures of internal combustion engines inefficiently use high oil pressure and require extensive machining, leading to increased weight and man-hours, with oil not being effectively reused and potentially causing oil mist generation and delayed return to the oil pan.
Innovation Solution
A lubricating structure where oil passages are shortened and shared between the balancer shaft and cylinder head, eliminating the need for individual pipes, and an oil return passage is designed to prevent oil contact with the balancer shaft, allowing quick return to the crankcase without generating oil mist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual oil passages are formed for each shaft bearing, then high oil pressure is delivered to each bearing, but the oil passages become lengthy and disordered, increasing weight and machining time
Solution Approach 1:
The patent combines multiple oil passages into a single integrated oil passage that branches within the crankcase to reach multiple bearings. This merging approach reduces the total length of oil passages and eliminates the need for multiple separate pipes, thereby reducing weight and machining time while still delivering high oil pressure to all necessary bearings including the balancer shaft and cylinder head.
Solution Approach 2:
The single oil passage is designed to serve multiple functions by branching to supply oil to different bearings and components. This multi-functional oil passage system delivers high oil pressure to the balancer shaft bearing, crankshaft bearing, and cylinder head lubrication points simultaneously, eliminating the need for separate dedicated passages for each component.
2Device complexity
If oil is returned directly to the oil pan after lubricating bearings, then the lubrication cycle is simple, but high oil pressure is not effectively reused and oil pressure may be slightly lowered due to increased passage length
Solution Approach 1:
The patent implements a continuous oil circulation system where oil that has lubricated the bearings is not immediately returned to the oil pan but is instead redirected to the cylinder head for continued useful action. The oil passage extends from the balancer shaft bearing through the crankcase to the cylinder head, ensuring that high pressure oil remains in use for additional lubrication functions before returning to the oil pan, thereby maximizing pressure utilization efficiency.
3Adaptability or versatility
If oil passages are extended to reach multiple components, then comprehensive lubrication is achieved, but the oil passages become longer and more complex, potentially lowering oil pressure
Solution Approach 1:
The patent resolves the pressure loss issue by changing the spatial arrangement of oil passages from a linear extended path to a three-dimensional network within the crankcase. The oil passage is formed to extend in multiple directions and branch to reach different bearings and the cylinder head, utilizing the available space within the crankcase volume rather than creating long external passages. This dimensional optimization maintains shorter passage lengths while achieving comprehensive lubrication coverage.
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
This configuration effectively uses high oil pressure for lubrication, reduces machining weight and time, and prevents oil mist generation, enabling efficient oil reuse and quick return to the oil pan.
Implementation Method 1
oil with high oil pressure is delivered from the oil pump to the main gallery. The oil with high oil pressure is fed from the main gallery to the bearing of the balancer shaft through the oil passage
Implementation Method 2
the balancer shaft is rotatably supported on the bearing by an oil film of the oil so that the balancer shaft can be prevented from seizing
Implementation Method 3
an outlet of the oil return passage is connected to a balancer chamber on a front side of the crankcase relatively to the balancer shaft
Data Source
AI summary
An aspect of the invention is directed to a lubricating structure of an internal combustion engine for feeding oil from an oil pump to respective portions of the internal combustion engine where a balancer shaft is disposed in parallel with a crankshaft in a crankcase, wherein: a main gallery and an oil passage are provided in the crankcase so that oil can be delivered from the oil pump to the main gallery and the oil of the main gallery can be guided by the oil passage to pass through a bearing of the balancer shaft; and the oil passage feeds the oil that has passed through the bearing of the balancer shaft to a cylinder head.