Gas Feed Unit for Exhaust Analysis with Purge and Outflow Nozzle
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Solution Overview
Problem
Existing gas feed units for exhaust gas analysis in internal combustion engines face challenges in achieving accurate measurements at small through-flow rates, leading to inaccurate results due to contamination and significant dilution effects on the engine's combustion processes.
Innovation Solution
A gas feed unit design with a sample gas line opening into a common connection line, featuring shut-off valves and an outflow nozzle to minimize contamination and dead volumes, allowing rapid and accurate delivery of sample gas while preventing backflow and enabling efficient purging and calibration, thereby reducing measurement inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If strong dilution is used to obtain adequate through-flow rates for analysis, then through-flow rate is improved, but measurement accuracy deteriorates due to contamination and reaching measurement limits
Solution Approach 1:
The gas feed unit is divided into multiple independent gas lines (sample gas line, calibration gas line, purge gas line) with separate shut-off valves, allowing independent control of each gas flow path. This segmentation prevents contamination between different gas streams and enables precise control of sample gas delivery to measurement units.
Solution Approach 2:
The invention extracts and removes dead volumes from the gas feed system by optimizing the connection line design and positioning the outflow nozzle at the end of the common connection line. This extraction of dead volume eliminates contamination sources and reduces gas retention that would otherwise compromise measurement accuracy at low through-flow rates.
2Object-affected harmful factors
If small through-flow rates are used to minimize effect on engine combustion, then engine impact is reduced, but measurement accuracy deteriorates due to contamination from previous gas supplies
Solution Approach 1:
The purge gas line is configured to perform preliminary purging of the common connection line before sample gas measurement. The shut-off valve in the purge gas line can be opened to flush out residual gases from previous measurements, ensuring the measurement path is clean and free from contamination before introducing new sample gas at small through-flow rates.
Solution Approach 2:
The common connection line acts as an intermediary path that receives gas from multiple sources (sample gas line, calibration gas line, purge gas line) and delivers to measurement units. The outflow nozzle positioned at the end of this common connection line serves as a mediator to rapidly evacuate residual gases, preventing backflow and contamination of subsequent measurements.
3Loss of time
If rapid measurement is implemented with small through-flow rates, then response time is improved, but contamination from previous gases increases measurement errors
Solution Approach 1:
The system implements periodic purging cycles through the purge gas line to clear residual gases from the common connection line between measurements. This periodic action, controlled by the shut-off valve, ensures that each measurement cycle starts with a clean path, enabling rapid sequential measurements without cross-contamination.
Solution Approach 2:
The outflow nozzle positioned at the end of the common connection line enables rapid evacuation of residual gases by creating a strong outflow that rushes through the connection line. This skipping action quickly removes contamination before the next measurement, enabling fast response times without sacrificing accuracy.
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 solution enables rapid and accurate measurement results with minimal impact on the engine, allowing for precise analysis of exhaust gases at small through-flow rates without contamination, ensuring reliable and precise data even in conditions of exhaust gas recirculation.
Implementation Method 1
a pump (16) for delivering the sample gas flow out of an exhaust gas source
Implementation Method 2
shut-off valves (24, 28, 36, 38, 40, 46) in the calibration gas line, the purge gas line and the sample gas line via which the sample gas flow, the calibration gas flow and the purge gas flow can be selectively shut off or released
Implementation Method 3
an outflow line (48) with an outflow nozzle (50) and a shut-off valve (52) arranged therein, wherein the outflow line (48) is configured to branch off from the common connection line (20)
Data Source
AI summary
A gas feed unit for an exhaust gas analysis unit includes a measurement unit for analysing a sample gas, a connection line arranged so that a calibration gas line, a purge gas line, and a sample gas line opens thereinto and which fluidically connects to the measurement unit, a shut-off valve arranged in each of the calibration gas line, the purge gas line, and the sample gas line, a pump which delivers the sample gas from an exhaust gas source, an outflow line with an outflow nozzle and a shut-off valve, and an outflow nozzle arranged at an end of the connection line opposite to the measurement unit. The outflow line branches off from the connection line. The sample gas line is arranged to open into the connection line between the measurement unit, the calibration gas line, and the purge gas line.