OHV Engine Lubricant Retention via Bent Blow-by Path
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Solution Overview
Problem
In OHV engine devices, direct communication between the push-rod chamber and cam chamber leads to lubricant mist formation, causing excessive lubricant consumption as it flows out to the cylinder head through these chambers.
Innovation Solution
A bypass passage is formed between the tappet holder and the cylinder bore to partition the cam and push-rod chambers, creating a bent blow-by gas path that induces lubricant adhesion to the wall surfaces, reducing lubricant flow to the cylinder head. This includes recessing parts of the cylinder bore side inner walls and configuring the camshaft to minimize lubricant splashes and enhance blow-by gas collision with chamber walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the push-rod chamber and the cam chamber are directly communicated with each other, then the blow-by gas path is simplified and lubricant can flow directly from the crank case to the cylinder head, but this causes excessive lubricant consumption and loss
Solution Approach 1:
The invention divides the cam chamber into multiple segments using partition walls. Each segment has its own blow-by gas passage that communicates with the push-rod chamber at different positions. This segmentation prevents lubricant mist from directly flowing from one chamber to another while maintaining separate blow-by gas paths, thereby reducing lubricant consumption without overly complicating the overall structure.
Solution Approach 2:
The invention creates different local structures within the cam chamber by forming partition walls at specific locations. The partition walls are positioned to create segments that locally control the flow paths. This local differentiation allows the blow-by gas to take different routes while preventing lubricant mist from bypassing the intended path, thus reducing lubricant loss without requiring complete restructuring of the entire chamber.
2Loss of substance
If the cam chamber is partitioned into multiple segments, then lubricant capture is improved, but the device complexity increases
Solution Approach 1:
The cam chamber is divided into multiple segments using partition walls that extend from the chamber walls toward the center. Each segment contains a cam lobe and has its own blow-by gas passage. This segmentation allows lubricant mist to be captured more effectively in each segment while maintaining a relatively simple overall structure that integrates well with the existing engine architecture.
Solution Approach 2:
The partition walls serve dual functions: they segment the cam chamber to improve lubricant capture and simultaneously form part of the blow-by gas passage structure. By merging these functions into a single structural element, the invention reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved lubricant retention.
3Loss of substance
If the bypass passage is positioned close to the inner walls of the push-rod chamber, then lubricant adhesion to walls is enhanced, but the passage configuration becomes more complex
Solution Approach 1:
The bypass passage is positioned close to the inner walls of the push-rod chamber at specific locations rather than uniformly throughout. This localized positioning creates areas where lubricant mist can adhere to the walls, improving capture efficiency. The passage maintains a relatively simple overall configuration by being strategically placed only where it provides maximum benefit for lubricant capture.
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 solution effectively captures and retains lubricant within the engine, reducing its flow to the cylinder head, thereby minimizing lubricant consumption and optimizing engine efficiency.
Implementation Method 1
induces adhesion of lubricant to the wall surface or bonding of droplets of lubricant in the mist-form by having the blow-by gas collide with a wall surface within the bent blow-by gas path
Implementation Method 2
having the blow-by gas collide with a wall surface within the bent blow-by gas path
Data Source
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AI summary
An engine device includes, in a cylinder block 6 thereof, a cylinder bore 73, a cam chamber 76 accommodating a camshaft 75, a push-rod chamber 78 accommodating a push-rod 77, and a tappet holder 80 configured to hold a tappet 79 in a slidable manner, the tappet 79 being configured to transmit a drive force from the camshaft 75 to the push-rod 77. The tappet holder 80 partitions the cam chamber 76 and the push-rod chamber 78. A bypass passage 83 communicating the cam chamber 76 with the push-rod chamber 78 is formed between the tappet holder 80 and the cylinder bore 73.