Coaxial Pump Arrangement for Engine Lubrication
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Solution Overview
Problem
Existing lubrication structures for internal combustion engines face challenges in miniaturization, drive force loss, and lubrication performance due to the positioning of scavenging pumps and oil passages, which lead to increased resistance and pressure loss, resulting in compromised engine compactness and efficiency.
Innovation Solution
The lubrication structure optimally arranges the feed pump and scavenging pump coaxially, with the scavenging pump positioned at least partially above the crank chamber's lower end and the rear end aligned with the crank chamber's rear end, reducing oil passage length and minimizing drive force loss by positioning the pump drive mechanism relative to the oil surface to reduce resistance and air bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the scavenging pump is arranged at a position lower than the lowest surface of the crank chamber, then the oil can be discharged from the crank chamber, but the engine size in vertical direction cannot be reduced and the drive force loss increases due to oil stirring
Solution Approach 1:
The scavenging pump is repositioned from a vertical arrangement (below the crank chamber) to a horizontal arrangement (coaxial with the feed pump at the rear of the crank chamber). This dimensional change allows the pump to be positioned at a height that does not increase engine vertical size while avoiding immersion in oil, thus resolving both the size and drive force loss issues.
2Loss of energy
If the position of the oil fan is lowered to prevent drive force loss, then the lowest ground height of the engine is lowered, but the oil passage length increases causing pressure loss
Solution Approach 1:
The scavenging pump and feed pump are merged into a coaxial arrangement at the rear of the crank chamber. This integration shortens the oil passage between the two pumps, reducing pressure loss while maintaining the oil fan at an optimal position that prevents drive force loss.
3Device complexity
If the oil is directly discharged from the scavenging pump toward the transmission, then the lubrication structure is simplified, but the oil is excessively supplied to the transmission causing drive force loss and air bubbles
Solution Approach 1:
The feed pump serves as an intermediary between the scavenging pump and the transmission. Oil discharged from the scavenging pump is first received by the feed pump, which then controls and regulates the oil supply to the transmission, preventing excessive oil supply and air bubble formation while maintaining structural simplicity.
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 results in a compact lubrication structure with improved lubrication performance, reduced drive force loss, and enhanced oil supply efficiency, allowing for a lower engine height and better lubrication distribution within the engine.
Implementation Method 1
a scavenging pump configured to suck the oil accumulated in the crank chamber and to discharge the oil to the transmission chamber
Implementation Method 2
a feed pump configured to supply oil in the oil chamber to a lubrication target part
Data Source
AI summary
There is provided a lubrication structure of an internal combustion engine. A transmission chamber is arranged adjacently at the rear of a crank chamber. An oil chamber communicates with a bottom part of the transmission chamber. A feed pump supplies oil in the oil chamber to a lubrication target part. A scavenging pump sucks the oil in the crank chamber and discharges the oil to the transmission chamber. The feed pump and the scavenging pump are arranged coaxially in a width direction of the internal combustion engine. At least a part of the scavenging pump is arranged higher than a lower end of the crank chamber. A rear end of the scavenging pump is arranged at the same position as a rear end of the crank chamber or in front of the rear end of the crank chamber in a front and rear direction.