Ejector Valve Regulates Working Fluid Flow Rate
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Solution Overview
Problem
Existing ejector systems in blow-by gas returning devices experience an increase in blow-by gas flow rate as supercharging pressure rises, leading to excessive engine oil consumption and altered air-fuel ratios, which can deteriorate engine exhaust emissions.
Innovation Solution
An ejector design with a nozzle featuring a valve to regulate the flow rate of working fluid, including a valve seat, movable valve element, and a spring to control the valve element's movement, preventing excessive negative pressure generation and flow rate increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the supercharging pressure rises, then the air flow rate in the bypass passage increases and negative pressure generation improves, but the blow-by gas flow rate becomes excessive causing engine oil consumption and air-fuel ratio deterioration
Solution Approach 1:
The valve element is made movable to dynamically adjust the nozzle opening area based on working fluid pressure. As pressure increases, the valve element moves to reduce the opening area, thereby regulating the working fluid flow rate and preventing excessive negative pressure generation that would cause excessive blow-by gas flow rate
Solution Approach 2:
The valve mechanism changes the flow parameters of the working fluid by adjusting the nozzle opening area. This dynamic parameter adjustment allows the system to maintain optimal blow-by gas flow rate across varying supercharging pressure conditions, preventing both insufficient and excessive gas flow
2Productivity
If the working fluid flow rate increases to generate higher negative pressure, then the ejector performance improves, but the blow-by gas returning amount increases excessively
Solution Approach 1:
The valve mechanism provides automatic feedback control where the working fluid pressure itself acts on the valve element to regulate the nozzle opening. This self-regulating feedback mechanism ensures that the working fluid flow rate and resulting negative pressure remain within optimal ranges, preventing excessive blow-by gas return and associated engine oil consumption
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
The design effectively suppresses the increase in flow rate of working fluid and target fluid, reducing engine oil consumption and stabilizing air-fuel ratios, thereby improving exhaust emissions by regulating the flow rate and preventing valve element movement issues due to sludge.
Implementation Method 1
the working fluid injected from the nozzle generates negative pressure in the decompression chamber to suck in the target fluid through the suction port
Implementation Method 2
a nozzle provided in the outer pipe on the entrance side for working fluid, the nozzle including a leading end portion placed in the decompression chamber to inject the working fluid
Implementation Method 3
a spring to urge the valve element in a direction to separate from the valve seat
Data Source
AI summary
An ejector includes: a decompression chamber in an outer pipe on an air entrance side; a throat in the outer pipe on an air exit side; a nozzle in the outer pipe on the air entrance side, the nozzle having a leading end portion placed in a decompression chamber to inject air; and a suction port in the decompression chamber to suck blow-by gas into the decompression chamber. The air injected from the nozzle generates negative pressure in the decompression chamber to suck in blow-by gas through the suction port, and the sucked gas is discharged together with air through a throat. The valve in the nozzle includes a valve seat, a valve element, and a spring to press the valve element in a direction to separate from the valve seat. The valve element is formed with a bottom-closed cavity opening toward an upstream side of an air flow.