Dry-sump Engine Oil Return Hole Reduces Scavenge Pump Load
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Solution Overview
Problem
Internal combustion engines with dry-sump lubrication face challenges in managing oil levels, leading to increased rotational friction and high loads on the scavenge pump due to larger oil tanks, which in turn increase engine size.
Innovation Solution
The design incorporates an oil return hole and guide rib to redirect excess oil from the oil tank back to the oil pan, preventing the tank from becoming full and reducing the load on the scavenge pump, allowing for a smaller oil tank size without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil tank is formed to be larger to prevent it from becoming full, then the load on the scavenge pump is reduced, but the size of the internal combustion engine increases
Solution Approach 1:
The invention extracts the excess oil from the oil tank through a dedicated return passage that connects the oil tank to the oil pan. This extraction mechanism allows the oil tank to maintain a smaller volume while preventing fullness, thereby reducing scavenge pump load without increasing engine size.
Solution Approach 2:
The invention introduces an intermediary return passage and return hole as a mediator between the oil tank and oil pan. This intermediary structure provides a controlled path for excess oil to return to the oil pan, enabling the oil tank to remain small while managing oil levels effectively.
2Quantity of substance
If the pump volume of the scavenge pump is set to be larger than the feed pump to prevent excessive oil in the oil pan, then the oil level is controlled, but the engine size increases
Solution Approach 1:
The invention extracts excess oil from the oil tank through the return passage before it can cause the tank to become full. This extraction approach allows for smaller pump volumes while maintaining effective oil level control, thereby avoiding engine size increase.
Solution Approach 2:
The invention applies partial action by providing a dedicated return path for only the excess oil that exceeds the tank's capacity, rather than requiring the scavenge pump to handle all oil circulation. This allows for smaller pump volumes while maintaining oil level control.
3Volume of moving object
If the oil tank is made smaller to reduce engine size, then the engine becomes more compact, but the scavenge pump experiences high load
Solution Approach 1:
The invention extracts excess oil from the oil tank through the return passage, preventing the tank from becoming full. This extraction mechanism allows the oil tank to be smaller while simultaneously preventing high load on the scavenge pump, as the return passage continuously removes excess oil.
Solution Approach 2:
The return passage acts as an intermediary that mediates between the oil tank and oil pan, providing a pressure relief path that prevents the scavenge pump from experiencing high load while allowing the oil tank to remain compact.
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 allows for a reduction in oil tank size while maintaining stable oil supply and preventing excessive load on the scavenge pump, enhancing engine efficiency and compactness.
Implementation Method 1
An oil return hole that connects together the oil tank and the first chamber is formed in an upper portion of the first side wall
Implementation Method 2
The internal combustion engine include a guide rib protruding from the first side wall toward the first chamber. The guide rib may be formed so as to guide oil, which flows into the first chamber from the oil tank through the oil return hole, into the oil pan
Data Source
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AI summary
An internal combustion engine (10) includes: a first side wall (21) that partitions the inside of a crank case (11) into a first chamber (31) and a second chamber (32); an oil pan (25) provided on a bottom portion of the first chamber (31); an oil tank (33) formed in the second chamber (32); a scavenge pump (40) having an intake port (41) that communicates with the oil pan (25) and a discharge port (42) that communicates with the oil tank (33); and a feed pump (50) having an intake port (51) that communicates with the oil tank (33). An oil return hole (63) that connects together the oil tank (33) and the first chamber (31) is formed in an upper portion of the first side wall (21).