Dual-Channel Exhaust Sampling System for Diesel and Otto Engines
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Solution Overview
Problem
Existing systems for taking exhaust gas samples from internal combustion engines, such as CVS systems, are not suited for simultaneous sampling of both diesel and Otto engines due to particle and HC deposits, leading to measurement distortions and increased complexity and costs.
Innovation Solution
A system with two exhaust gas channels and air channels connected through mixing zones and a shared dilution tunnel, using a common sampling probe and pump, which reduces production and assembly costs while ensuring reliable and homogeneous mixing and sampling for both engine types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single CVS system is used for both diesel and Otto engines, then device complexity and costs are reduced, but measurement precision deteriorates due to particle and HC deposits in the mixing zone
Solution Approach 1:
The system is segmented into two separate gas flow paths: one for diesel engines and one for Otto engines. Each path has its own mixing zone, allowing independent handling of different exhaust gas types. This segmentation prevents cross-contamination of particle and HC deposits between engine types while sharing common components downstream (dilution tunnel, sampling probe, pump), thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The dilution tunnel, sampling probe, and conveying pump are designed as universal components that can handle both diesel and Otto engine exhaust gases. These shared components perform multiple functions for different engine types, reducing overall system complexity and costs while maintaining measurement precision through the segregated mixing zones upstream.
2Measurement precision
If separate systems are used for diesel and Otto engines, then measurement precision is maintained, but device complexity and production costs increase
Solution Approach 1:
The system segments only the critical mixing zones for each engine type while keeping downstream components unified. This partial segmentation maintains measurement precision by preventing deposit cross-contamination, yet avoids full system duplication that would increase complexity and costs.
Solution Approach 2:
The dilution tunnel, sampling probe, and conveying pump are merged into a single shared system for both diesel and Otto engines. This merging reduces device complexity, production costs, and space requirements while the segregated mixing zones preserve measurement precision.
3Device complexity
If a single dilution tunnel is used for both engine types, then space requirements and production costs are reduced, but reliability deteriorates due to potential measurement distortions
Solution Approach 1:
The system segments the mixing zones upstream of the dilution tunnel for different engine types, while the dilution tunnel itself remains shared. This ensures that diesel and Otto exhaust gases are mixed separately before entering the common dilution tunnel, preventing measurement distortions and maintaining sampling reliability while using a single tunnel.
Solution Approach 2:
The segregated mixing zones act as intermediaries that prepare the exhaust gases from different engine types separately before they converge in the shared dilution tunnel. This intermediary preparation ensures compatibility and prevents contamination, maintaining reliability in the shared downstream system.
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
Enables reliable particle and HC measurements for both diesel and Otto engines with reduced production and assembly costs, minimizing space requirements and avoiding measurement distortions by separating critical regions and using identical components.
Implementation Method 1
a pump for conveyance of the diluted exhaust gas/air mixture
Implementation Method 2
a first mixing zone in which the first exhaust gas channel enters the first air channel... configured to mix the first exhaust gas with the ambient air
Data Source
AI summary
A system for taking an exhaust gas sample includes a first exhaust gas channel fluidically connected to a first exhaust gas source via a first exhaust gas inlet. A first air channel with a first air filter is configured to suck in ambient air. The first exhaust gas channel meets the first air channel in a first mixing zone, where a first exhaust gas is mixed with the ambient air to obtain a diluted exhaust gas/air mixture. A second exhaust gas channel is fluidically connected to a second exhaust gas source via a second exhaust gas inlet, and a second mixing zone. A control device and a measurement device are configured to respectively control and measure mass flows. The diluted exhaust gas/air mixture flows either from the first exhaust gas source or from the second exhaust gas source into the dilution tunnel and to at least one sampling probe.