EGR Distribution Measurement Using Vacuum Pump Sampling
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Solution Overview
Problem
Conventional methods for measuring exhaust gas recirculation (EGR) distribution among engine cylinders are time-consuming and inefficient due to the need for individual cylinder sampling and the use of external gas analyzers, which introduce significant delays in gas transport and analysis.
Innovation Solution
A method involving the fluid coupling of intake runners to a vacuum pump, which actively draws intake charge gas to a gas composition sensor, allowing for simultaneous sampling from multiple cylinders and reducing transport delays, and utilizing ceramic gas composition sensors for faster and more accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional external gas analyzers are used to measure EGR distribution, then measurement accuracy can be maintained, but gas transport delays significantly increase measurement time
Solution Approach 1:
The patent extracts the gas composition sensing function from the external gas analyzer and places it directly at the intake runner, eliminating the need for gas transport through tortuous paths. This extraction of the measurement function to the source location resolves the contradiction by maintaining measurement capability while eliminating transport delays.
Solution Approach 2:
The patent introduces a vacuum pump as an intermediary device to actively transport a controlled portion of intake charge gas directly to the gas composition sensor. This intermediary system enables fast, direct gas delivery without the delays of passive diffusion or long transport paths, resolving the time-accuracy contradiction.
2Measurement precision
If individual cylinder-by-cylinder sampling is performed, then complete EGR distribution characterization is achieved, but testing duration becomes excessively long
Solution Approach 1:
The patent merges multiple sampling functions into a single integrated system where one vacuum pump serves multiple intake runners and multiple gas composition sensors simultaneously measure different cylinders. This combination enables parallel measurement across all cylinders, achieving complete EGR distribution characterization without the time penalty of sequential testing.
3Productivity
If multiple intake runners are connected to a single vacuum pump, then simultaneous multi-cylinder sampling is enabled, but system complexity increases
Solution Approach 1:
The vacuum pump is designed as a universal device that can serve multiple intake runners simultaneously through a distributed sensor arrangement. This multi-functional configuration enables the single vacuum pump to perform what would traditionally require multiple separate sampling systems, achieving high productivity without proportionally increasing complexity.
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 significantly reduces the time and cost associated with EGR system development and validation by enabling faster, more efficient measurement of EGR distribution across multiple cylinders, maintaining accuracy and reliability.
Implementation Method 1
the vacuum pump actively draws the intake charge gas to the gas composition sensor, thereby reducing transport delays for sampling gas from the cylinder intake runners to the gas composition sensors
Implementation Method 2
measuring an oxygen concentration of the diverted intake charge portion with the gas composition sensor, and estimating an EGR concentration of the intake charge based on the measured oxygen concentration
Data Source
AI summary
Methods and systems are provided for measuring exhaust gas recirculation (EGR) distribution among individual engine cylinders. In one example, a method may include fluidly coupling a plurality of intake runners of an engine to a vacuum pump, diverting a portion of intake charge gas from the intake runner to a gas composition sensor with the vacuum pump, measuring an oxygen concentration of the diverted intake charge portion with the gas composition sensor, and estimating an EGR concentration of the intake charge based on the measured oxygen concentration.