Compressor MWE Inlet with Integrated CCV Recirculation
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Solution Overview
Problem
Existing turbochargers face instability issues due to surge conditions, particularly at low compressor volumetric air flow rates, which can lead to pulsations and reduced engine efficiency, and combining a Map Width Enhanced (MWE) structure with Crankcase Ventilation (CCV) inlet can increase compressor housing size.
Innovation Solution
A compressor design with a housing featuring a Map Width Enhanced (MWE) inlet structure and a Crankcase Ventilation (CCV) conduit integrated into the compressor inlet, where the CCV gases are delivered through a port and passage system that assists in stabilizing the compressor operation by recirculating gases and reducing surge, while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Map Width Enhanced (MWE) structure with Crankcase Ventilation (CCV) inlet is combined, then compressor stability and surge margin are improved, but compressor housing size increases
Solution Approach 1:
The CCV conduit is nested within the MWE inlet structure, with the CCV outlet positioned at the upstream end of the MWE slot. This nesting allows the CCV passage to be accommodated within the existing MWE inlet geometry, integrating two functions (MWE and CCV) into a single compact structure without significantly increasing overall housing volume
Solution Approach 2:
The inlet structure serves multiple functions: the MWE slot provides map width enhancement for surge margin improvement, while the integrated CCV conduit provides crankcase ventilation. The MWE inlet structure itself acts as both the outer inlet wall and houses the CCV passage, making the system multi-functional and avoiding the need for separate dedicated structures
2Power
If compressor operates at low volumetric air flow rate and high boost pressure, then engine power is maintained, but surge condition occurs causing pulsations and instability
Solution Approach 1:
The CCV conduit creates a feedback mechanism by recirculating crankcase gases back through the MWE slot to the compressor inlet. This recirculated flow provides a stabilizing effect that counteracts surge conditions, allowing the compressor to maintain stable operation at low flow rates and high boost pressures where surge would normally occur
Solution Approach 2:
The MWE slot acts as an intermediary structure that serves dual purposes: it allows additional air to be drawn into the compressor under high flow conditions, and simultaneously serves as the outlet for the CCV conduit to deliver recirculated gases. This intermediary structure mediates between the CCV system and the main compressor flow, enabling surge suppression without disrupting normal compression function
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 integrated MWE and CCV system enhances compressor stability, increases the surge margin, and allows for a wider engine speed range operation without significantly increasing the compressor housing size, thereby improving engine efficiency and matching compressor performance with varying engine speeds.
Implementation Method 1
the CCV outlet at its upstream end. The MWE slot acts as the outlet for the CCV conduit so that CCV gases are drawn into the inlet upstream of the gas flow passage
Data Source
AI summary
A compressor for a turbocharger is supplied with crank case ventilation (CCV) gases from the engine which is turbocharged. The CCV gases are piped into an inlet of the compressor housing which supports an insert with an MWE structure. The MWE structure comprises an outer wall and an inner wall with a gas flow passage defined between them. At high r.p.m. of the compressor impeller air flows through the passage to provide more air volume to the impeller and at low r.p.m. excess air is bled out of the passage for recirculation. The CCV gases are directed to a position upstream of an inlet to the gas flow passage where they emerge through an outlet which may be defined in the insert. The CCV gases may be supplied to the outlet via a chamber defined between the insert and the compressor housing. The arrangement provides for improved mixing of CCV gases with the incoming air and does not compromise noise reduction.