Crankcase Ventilation Leakage Detection via Negative Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing crankcase ventilation devices in internal combustion engines cannot reliably detect leakages outside connecting points, and existing leakage testing methods are limited in their ability to identify faults accurately.
Innovation Solution
A method and system that create a negative pressure in the crankcase using an electrically driven delivery device, such as a side channel compressor, and measure the resulting gas pressure with a pressure sensor, allowing for the detection of leakages by comparing the measured pressure to a tolerance range, which accounts for factors like ambient temperature and piston ring wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical resistance sensing is used to detect connecting point issues, then connection faults can be detected, but leakage outside connecting points cannot be detected and false positives occur
Solution Approach 1:
The patent replaces the electrical resistance sensing system with a pressure-based detection system. Instead of using electrical contacts to detect connection faults, the system uses a pressure sensor to measure pressure changes in the crankcase ventilation system. This substitution allows detection of actual gas leaks rather than just electrical connection issues, eliminating false positives while maintaining detection reliability.
Solution Approach 2:
The patent changes the detection parameter from electrical resistance to pressure. By measuring pressure changes in the crankcase ventilation system during engine operation, the system can accurately detect actual gas leaks. The control unit compares measured pressure values against threshold values to determine leakage conditions, providing reliable detection without the false positives associated with electrical sensing methods.
2Ease of operation
If piston ring play is increased to reduce friction, then piston movement is improved, but complete fluidic separation of combustion space and crankcase is lost
Solution Approach 1:
The patent implements a feedback control system where a pressure sensor continuously monitors the pressure in the crankcase ventilation system and transmits this information to a control unit. The control unit processes the pressure data and activates the blow-by gas discharge device when leakage is detected, creating a closed-loop feedback mechanism that maintains reliable pressure control despite the inherent blow-by gas flow caused by piston ring play.
Solution Approach 2:
The patent introduces a blow-by gas discharge device as an intermediary component between the crankcase and the external environment. This device selectively allows controlled discharge of blow-by gas while preventing uncontrolled leakage, thereby maintaining crankcase pressure control and reliability without requiring tighter piston ring clearance that would increase friction.
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 approach enables reliable detection of leakages in the crankcase ventilation device, including those outside connecting points, by accurately measuring changes in gas pressure, reducing false positives and improving maintenance efficiency.
Implementation Method 1
a side channel compressor (5) including a rotating blade impeller, which between an inlet (51) and an outlet (52) of the side channel compressor creates a pressure differential
Implementation Method 2
at least one pressure sensor (9) is present in the internal combustion engine, which measures the gas pressure in the crankcase
Data Source
AI summary
An internal combustion engine for a motor vehicle includes a crankcase ventilation device for removing blow-by gas from a crankcase, a pressure sensor being provided for measuring the gas pressure in said crankcase, and a control unit connected to and in communication with the crankcase ventilation device being configured and/or programmed to run a tightness test for said crankcase ventilation device when the internal combustion engine is switched off.