Internal Combustion Engine Blow-by Gas Recirculation via Dual Passages
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Solution Overview
Problem
Internal combustion engines face inefficiencies in recirculating blow-by gases into the intake passage, particularly in managing pressure differences between the crankcase and intake passage, which affects the effective introduction of blow-by gases into the combustion chambers during both natural aspiration and supercharged operations.
Innovation Solution
The implementation of a supercharger, an oil tank, a scavenging pump, and one-way valves in specific passages within the engine system, allowing for efficient communication and pressure management between the oil tank, crankcase, and intake passage, ensuring blow-by gases are effectively introduced into the combustion chambers regardless of operational mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single passage connects the crankcase to the intake passage downstream of the supercharger, then the structure is simple, but blow-by gas cannot be effectively introduced into the intake passage during supercharged operation due to pressure differences
Solution Approach 1:
The single passage is divided into two separate passages: a first passage connecting the crankcase to the downstream side of the supercharger, and a second passage connecting the crankcase to the upstream side of the supercharger. This segmentation allows independent control of blow-by gas flow paths for different operating conditions, enabling effective gas introduction during both natural aspiration and supercharged operations.
Solution Approach 2:
The system dynamically adapts the blow-by gas flow path based on operating conditions. During natural aspiration operation, the first passage is used; during supercharged operation, the second passage is used. This dynamic adaptation ensures optimal performance across different engine operating modes.
2Power
If the intake passage pressure is higher than crankcase pressure during supercharged operation, then the supercharger functions properly, but blow-by gas flow from crankcase to intake passage is blocked
Solution Approach 1:
By providing two separate passages, the system allows the second passage to serve as an alternative route for blow-by gas recirculation when the first passage becomes blocked due to pressure differences during supercharged operation.
Solution Approach 2:
The system changes the flow path parameter based on pressure conditions. When pressure in the downstream side exceeds crankcase pressure, the system switches from using the first passage to using the second passage, maintaining blow-by gas recirculation functionality.
3Ease of operation
If a one-way valve is installed in the first passage, then blow-by gas flows correctly during natural aspiration, but the valve may interfere with flow during supercharged operation
Solution Approach 1:
The one-way valve is placed only in the first passage, while the second passage operates without a valve. This segmentation allows the valve to control flow during natural aspiration operation, while the second passage provides an unobstructed alternative path during supercharged operation.
Solution Approach 2:
The second passage acts as an intermediary route that becomes active when the first passage (with the one-way valve) becomes obstructed during supercharged operation, ensuring continuous blow-by gas recirculation.
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 enhances the efficient introduction of blow-by gases into the intake passage, reducing oil deterioration, minimizing foreign substance adhesion, and maintaining a simpler engine design by leveraging pressure differences and scavenging pump operation.
Implementation Method 1
a scavenging pump provided in the collecting passage and configured to transport a fluid in the crankcase to the oil tank
Implementation Method 2
The one-way valve is provided in the first passage and allows the fluid to flow only from the upper space toward the intake passage
Data Source
AI summary
An internal combustion engine includes a supercharger, an oil tank, a scavenging pump, a first passage, a second passage, and a one-way valve. The supercharger is provided in an intake passage. The oil tank communicates with a crankcase via a collecting passage. The scavenging pump is provided in the collecting passage to transport a fluid in the crankcase to the oil tank. The first passage connects an upper space located above a liquid surface in the oil tank and a downstream portion of the intake passage located on a downstream side with respect to the supercharger. The second passage connects the upper space and an upstream portion of the intake passage located on an upstream side with respect to the supercharger. The one-way valve is provided in the first passage and allows the fluid to flow only from the upper space toward the intake passage.