Internal Combustion Engine Intermediate Passage Step for Oil Backflow

The patent applies preliminary anti-action by designing the intermediate passage with a step that creates a barrier before oil backflow can occur. The step structure anticipates the oil backflow problem and prevents it by creating a physical obstruction that oil cannot overcome, while still allowing blow-by gas to pass through. This resolves the contradiction by preventing the harmful effect (oil backflow) without compromising the useful function (blow-by gas recirculation).

The patent applies local quality by creating a step structure at a specific location within the intermediate passage. This localized feature changes the flow characteristics only in the critical area where oil backflow occurs, while maintaining normal flow conditions elsewhere in the passage. The step creates a local barrier that selectively blocks oil while allowing gas to pass, resolving the contradiction between gas recirculation and oil backflow prevention.

The patent applies segmentation by dividing the intermediate passage into distinct sections with different cross-sectional areas. The passage is segmented into an upstream portion with larger area and a downstream portion with smaller area, separated by a step structure. This segmentation allows the passage to perform multiple functions: allowing gas flow in the upstream section and restricting oil flow in the downstream section, without requiring complex external components.

The patent applies inversion by reversing the typical passage design approach. Instead of maintaining a uniform or gradually changing cross-section, the passage abruptly changes area with a step structure. This inverted design creates a sudden constriction that effectively blocks oil backflow while maintaining simplicity in the overall passage structure, avoiding the need for complex valves or adjustable mechanisms.