Crankcase Ventilation System with EGR Integration
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Solution Overview
Problem
Existing crankcase ventilation systems in internal combustion engines often release oil vapors and pollutants into the atmosphere during the ventilation process, which can contribute to increased emissions and fail to effectively manage blow-by gases containing contaminants like hydrocarbons, carbon monoxide, and NOx.
Innovation Solution
A ventilation system that includes a first conduit connecting the engine's exhaust system to the crankcase, a second conduit for venting, and a valve controlled by a sensor and controller to selectively direct and restrict the flow of exhaust gases into the crankcase for purging, utilizing an EGR system to introduce inert exhaust gases to push out gaseous constituents while minimizing oil vapor emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If blow-by gases are vented directly to the atmosphere, then the crankcase is effectively ventilated and pressure is relieved, but pollutants and oil vapors are released into the atmosphere increasing emissions
Solution Approach 1:
The patent converts harmful blow-by gases containing pollutants and oil vapors into a beneficial resource by routing them through the EGR system where they mix with fresh intake air. This not only reduces atmospheric emissions but also utilizes the inert exhaust gases to dilute and cool the intake charge, improving combustion efficiency and reducing NOx formation.
Solution Approach 2:
The patent merges the crankcase ventilation system with the EGR system, combining two separate functions into one integrated system. The blow-by gases from the crankcase are merged with the exhaust gases in the EGR conduit, and both are reintroduced to the intake manifold, creating a unified gas recirculation and ventilation system.
2Object-generated harmful factors
If exhaust gases are recirculated through the EGR system, then combustion temperature is reduced and NOx emissions are decreased, but the system complexity increases
Solution Approach 1:
The patent makes the EGR system multi-functional by enabling it to perform both its traditional NOx reduction function and a new crankcase ventilation function. The same EGR conduit and intake manifold pathways are used to both recirculate exhaust gases for emission control and to vent blow-by gases from the crankcase, eliminating the need for separate ventilation components.
3Object-generated harmful factors
If the crankcase is continuously ventilated, then blow-by gases are effectively removed, but oil vapor losses increase and energy efficiency decreases
Solution Approach 1:
The patent implements periodic rather than continuous crankcase ventilation by utilizing the natural pressure fluctuations during engine operation. The vent valve opens periodically when pressure differential favors flow, allowing blow-by gases to be removed at appropriate intervals while minimizing continuous oil vapor losses and maintaining energy efficiency.
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 system effectively reduces the concentration of pollutants in the crankcase and minimizes atmospheric emissions by intermittently or continuously purging the crankcase with recirculated exhaust, using a catalytic unit to further reduce pollutants before venting, thereby reducing the amount of pollutants released into the atmosphere.
Implementation Method 1
because the pressure of the exhaust gases in the main exhaust conduit downstream from the particulate trap may be lower than the pressures within the crankcase of the engine, crankcase exhaust gases may flow from the crankcase to the main exhaust conduit without the aid of a pump
Implementation Method 2
using a catalytic unit to further reduce pollutants before venting
Data Source
AI summary
A ventilation system for an engine is disclosed. The ventilation system may include a first conduit configured to connect an exhaust system of the engine with a crankcase of the engine, a second conduit configured to connect to a vent of the crankcase, and a valve disposed within the second conduit. Additionally, the ventilation system may include a sensor configured to generate a signal indicative of a concentration of a gaseous constituent within the crankcase of the engine, and a controller in communication with the valve and the sensor, the controller being configured to selectively move the valve based on the signal.