Motorcycle Engine Crankcase Partition Walls for Oil Circulation
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Solution Overview
Problem
Internal combustion engines for motorcycles face challenges in oil circulation performance due to pressure variations in the crank chamber caused by high-speed rotation of the crankshaft, which can degrade oil circulation efficiency and require costly bypass passages, potentially increasing engine size.
Innovation Solution
The design includes a configuration with upper and lower crankcases that utilize partition walls with grooves to establish communication between the cam chain chamber, crank chamber, and clutch chamber, reducing pressure variations and enhancing oil circulation without the need for a bypass passage, thereby maintaining engine size and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bypass passage is added to improve oil circulation, then oil circulation performance is improved, but manufacturing cost increases
Solution Approach 1:
The clutch chamber serves multiple functions: it acts as both a functional chamber for the clutch mechanism and as a pressure equalization chamber that facilitates oil circulation. By allowing the clutch chamber to communicate with both the cam chain chamber and crank chamber, it performs the dual role of clutch housing and oil flow facilitator, eliminating the need for a separate bypass passage.
Solution Approach 2:
The clutch chamber acts as an intermediary chamber that mediates between the cam chain chamber and crank chamber. Instead of directly connecting these chambers with a bypass passage, the invention uses the clutch chamber as an intermediate medium to enable oil flow from the cam chain chamber to the crank chamber, thereby avoiding the need for additional passages.
2Reliability
If a bypass passage is added to improve oil circulation, then oil circulation performance is improved, but engine size increases
Solution Approach 1:
The clutch chamber serves multiple functions: it acts as both a functional chamber for the clutch mechanism and as a pressure equalization chamber that facilitates oil circulation. By allowing the clutch chamber to communicate with both the cam chain chamber and crank chamber, it performs the dual role of clutch housing and oil flow facilitator, eliminating the need for a separate bypass passage.
Solution Approach 2:
The invention merges the oil circulation function with the existing clutch chamber structure. Instead of adding a separate bypass passage that would increase engine size, the clutch chamber is integrated to perform both its original function and the additional function of facilitating oil circulation between chambers.
3Power
If the crankshaft rotates at high speed, then power output is improved, but pressure variations in the crank chamber increase
Solution Approach 1:
The clutch chamber acts as an intermediary chamber that mediates between the cam chain chamber and crank chamber. Instead of directly connecting these chambers with a bypass passage, the invention uses the clutch chamber as an intermediate medium to enable oil flow from the cam chain chamber to the crank chamber, thereby avoiding the need for additional passages.
Solution Approach 2:
The invention creates a pressure equalization pathway by connecting the cam chain chamber, clutch chamber, and crank chamber through communication holes. This allows pressure to equalize across chambers, reducing harmful pressure variations in the crank chamber while maintaining high-speed rotation capability.
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 significantly improves oil circulation performance by allowing easier flow of oil from the cam chain chamber to the crank chamber, preventing pressure differences and maintaining engine size and cost efficiency.
Implementation Method 1
pressure variations occur in the crank chamber. The pressure variations hinder the oil circulating in the cam chain chamber from flowing into the crank chamber
Data Source
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AI summary
In an internal combustion engine, upper and lower crankcases include a crank chamber, a clutch chamber in communication with the crank chamber, and a cam chain chamber. The upper crankcase includes a second upper partition wall configured to separate the cam chain chamber and the clutch chamber from each other. The lower crankcase includes a first lower partition wall configured to separate the cam chain chamber and the crank chamber from each other, and a second lower partition wall configured to separate the cam chain chamber and the clutch chamber from each other. An oil passage allowing communication between the cam chain chamber and the crank chamber is provided in the first lower partition wall. First passages allowing communication between the cam chain chamber and the clutch chamber are provided respectively in the bottom surface of the second upper partition wall and in the top surface of the second lower partition wall.