Optical Gas Sensor with Countercurrent Sealing
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Solution Overview
Problem
Existing systems for measuring gas and aerosol concentrations in internal combustion engines face challenges such as high energy consumption, mechanical complexity, and sensor contamination, particularly in monitoring oil mist concentrations, which can lead to false alarms and operational issues.
Innovation Solution
A compact measuring device with an optical sensor unit where the optical passage is laterally displaced relative to the compressed air nozzle's outlet direction, utilizing sealing air nozzles to create a countercurrent that prevents oil mist deposition on optical elements, and allowing for fresh air flushing to maintain sensor cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a blower is used to draw aerosol from the working chamber through a measuring compartment, then aerosol measurement can be performed, but the system requires considerable constructive and operating requirements and draws waste air through the pipe system causing oil deposits to form which clog the pipelines
Solution Approach 1:
The patent extracts only the necessary aerosol sample through a small opening in the cylinder head, eliminating the need for complex blower systems and extensive piping. The measurement compartment is integrated directly into the cylinder head structure, removing the need for separate external measurement chambers and associated ventilation systems.
Solution Approach 2:
The patent introduces a condensation trap as an intermediary component that captures oil deposits before they can reach and clog the optical measurement path. This simple trap prevents the harmful effect of oil bag formation while maintaining the necessary aerosol sampling function.
2Measurement precision
If a sensor unit is arranged directly in the interior of the working chamber, then aerosol concentration can be measured, but the base concentration of oil mist and splash oil contaminates the sensors leading to false alarms
Solution Approach 1:
The patent segments the measurement function into two distinct parts: (1) aerosol sampling through a controlled opening in the cylinder head, and (2) optical measurement in a separate, protected compartment. This separation allows the sensor to measure actual aerosol concentration while being protected from direct contact with oil mist and splash oil that would cause contamination and false alarms.
3Measurement precision
If a venturi pump is used to draw in the aerosol mixture from the driving chamber, then measurement can be performed without mechanically moved parts, but the energy expense of the venturi pump is very high
Solution Approach 1:
Instead of using a high-energy venturi pump to draw in the entire aerosol mixture, the patent applies a minimal action by using a small opening in the cylinder head to allow only the necessary amount of aerosol to enter the measurement compartment. This partial sampling approach eliminates the need for energy-intensive pumping while maintaining measurement capability.
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 solution reduces energy expenditure, achieves better measurement results, and prevents sensor contamination, enabling more reliable and efficient monitoring of aerosol concentrations without the need for complex air curtains or high-energy venturi pumps.
Implementation Method 1
an optical measuring path that comprises an optical emitter and an optical receiver may be provided
Implementation Method 2
a venturi pump for drawing in the aerosol mixture from the driving chamber through the optical measuring path
Data Source
AI summary
A measuring device (2) draws out an aerosol air mixture from the working chamber (4) of the machine and feeds it to an optical sensor unit with an optical emitter (15) and an optical receiver (17). A compressed air jet pump (8) includes a compressed air feed (26), a compressed air nozzle (32), a preferably funnel-shaped pressure discharge channel and an underpressure region (10), with the compressed air nozzle (32) having an outlet direction oriented substantially in the direction of the pressure discharge channel. The compressed air feed (26) is connected to a compressed air source. A suction line is connected between the working chamber (4) and the underpressure region (10). The optical sensor unit has an optical passage between the optical emitter (15) and the optical receiver (17) oriented substantially perpendicular to the outlet direction of the compressed air nozzle (32) and leads through the underpressure region.