OHV Engine Lubrication System Relief Valve Extraction
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Solution Overview
Problem
Conventional lubricating oil relief structures in vertical engines increase engine size and require extensive processing, leading to increased man-hours and complexity, especially when mounting a relief valve inside the lower crankcase.
Innovation Solution
A four-cycle OHV engine design featuring a crankshaft and camshaft with an oil pump and lubricating oil passages that include communication portions and extending portions to position the oil filter on the cylinder head side, allowing for a compact engine configuration with an integrated relief device that adjusts lubricating oil pressure using a relief valve and hole, reducing the need for separate processing and components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the oil filter is disposed on the extended line coupling the crankshaft and the camshaft, then the lubrication system is simplified, but the engine size increases
Solution Approach 1:
The patent repositions the oil filter from a vertical arrangement (on the extended line between crankshaft and camshaft) to a horizontal arrangement (in the width direction of the cylinder body). This dimensional change allows the lubrication system to remain simplified while reducing the engine's overall size in the vertical direction, thereby resolving the contradiction between system simplicity and compact dimensions.
2Device complexity
If the relief valve is mounted inside the lower crankcase, then the relief structure is integrated, but the number of processing steps and man-hours increases
Solution Approach 1:
The patent extracts the relief valve from the lower crankcase and relocates it to the side surface of the cylinder body. This extraction eliminates the need for complex internal processing of the lower crankcase while maintaining the integrated relief function, thereby reducing manufacturing complexity and processing time without sacrificing structural integration.
3Productivity
If the oil filter is positioned on the extended line of the crankshaft and camshaft, then the lubrication path is direct, but the engine width increases
Solution Approach 1:
The patent transitions the oil filter positioning from a longitudinal arrangement (along the crankshaft-camshaft line) to a lateral arrangement (in the width direction of the cylinder body). This dimensional repositioning maintains direct lubrication pathways for efficiency while optimizing the engine's width dimension, thereby resolving the contradiction between lubrication productivity and engine compactness.
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 design enhances workability, reduces processing time and costs, and achieves a compact engine configuration suitable for outboard motors by simplifying the lubrication system and reducing the number of man-hours required for machining, while maintaining efficient lubrication and engine performance.
Implementation Method 1
The oil pump and the lubricating oil passages are configured to pressure-feed lubricating oil to the bearings
Implementation Method 2
The relief device is configured to adjust a pressure of the lubricating oil. The relief device is disposed having a relief valve and a relief hole at the extending portions
Implementation Method 3
The bearings rotatably support the crankshaft and the camshaft
Data Source
AI summary
An engine case includes bearings, an oil pump, lubricating oil passages, and a relief device. The bearings rotatably support a crankshaft and a camshaft. The oil pump and the lubricating oil passages are configured to pressure-feed lubricating oil to the bearings. The relief device is configured to adjust a pressure of the lubricating oil. The lubricating oil passages include main lubricating oil passages. The main lubricating oil passages include communication portions linearly formed with extending portions. The communication portions communicate between the respective bearings of the crankshaft and the camshaft from outside the engine case. The extending portions extend from outside the engine case to the bearing of the camshaft. The relief device is disposed having a relief valve and a relief hole at the extending portions.