Turbocharged Engine PCV Flow Regulating Device
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Solution Overview
Problem
Turbocharged engines face challenges in managing crankcase vacuum levels during high boost conditions, leading to potential seal displacement and failure, while also needing to meet PCV icing and crankcase NOx requirements, which are often unmet due to restricted gas flow and water condensation in the PCV system.
Innovation Solution
A flow control system with a flow regulating device located in the PCV vent line, which selectively limits the flow of blowby gas to the turbocharger's air inlet, using a venturi nozzle or similar device to prevent excessive vacuum and manage gas flow, thereby reducing the risk of seal displacement and ensuring NOx compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the PCV line diameter is reduced or an orifice is provided to limit crankcase vacuum, then the crankcase negative pressure limit is protected, but PCV icing and crankcase NOx requirements are not met due to restricted gas flow
Solution Approach 1:
The patent employs a spring-loaded check valve that dynamically adjusts the PCV line opening based on crankcase pressure conditions. Under normal conditions, the valve remains closed to prevent vacuum exceedance. When crankcase pressure exceeds the negative pressure limit, the spring-loaded mechanism opens the valve to relieve excess vacuum, thereby dynamically adapting to varying engine operating conditions while maintaining seal integrity and meeting emissions requirements
Solution Approach 2:
The flow regulating device changes the flow resistance parameter dynamically through its spring-loaded check valve mechanism. By adjusting the valve opening degree in response to crankcase pressure changes, the system modifies the effective PCV line impedance, allowing sufficient gas flow to prevent icing and meet NOx requirements while limiting maximum vacuum levels to protect crankcase seals
2Stress or pressure
If the PCV line length is significantly extended to limit crankcase vacuum, then the vacuum level is controlled, but condensed water gathers and freezes in the PCV line
Solution Approach 1:
The patent extracts the flow control function from the PCV line geometry (diameter reduction or length extension) and implements it separately through a spring-loaded check valve device. This separation allows the PCV line to maintain its original short, horizontal configuration that prevents water condensation and freezing, while the dedicated valve component handles the vacuum limitation function independently
3Stress or pressure
If traditional methods with reduced PCV line diameter or extended length are used, then crankcase vacuum is limited, but development and testing time and costs increase significantly
Solution Approach 1:
The spring-loaded check valve is pre-configured with a specific spring force that corresponds to the desired crankcase negative pressure limit. This preliminary setting of the spring parameter allows the device to automatically maintain optimal crankcase vacuum levels without requiring extensive development testing, as the valve's opening pressure can be predetermined during manufacturing based on engine specifications
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 flow regulating device effectively limits crankcase vacuum at high boost conditions, preventing seal displacement and ensuring compliance with PCV icing and NOx requirements, while reducing development and testing time and costs compared to traditional methods.
Implementation Method 1
using a venturi nozzle or similar device to prevent excessive vacuum and manage gas flow
Data Source
AI summary
A flow control system is provided having an engine, a turbocharger, and positive crankcase ventilation (PCV) line, and a flow regulating device. The engine has an air-oil separator and an intake manifold. The air-oil separator separates oil droplets and oil mist from a blowby gas. The turbocharger has an air inlet and an air outlet, where the air outlet is connected to the intake manifold of the engine. The positive crankcase ventilation (PCV) vent line has a first end connected to the air-oil separator and a second end connected to the air inlet of the turbocharger. The PCV vent line delivers the blowby gas from the air-oil separator to the air inlet of the turbocharger. The flow regulating device is located in the PCV vent line. The flow regulating device selectively limits the flow of blowby gas from the air-oil separator to the air inlet of the turbocharger.