Gas Sensor Pump Cycling for Low-Concentration Measurement
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Solution Overview
Problem
Existing gas sensors face challenges in accurately measuring low concentrations of gas components, such as NOx, due to factors like inconsistent diffusion control, voltage and current measurement accuracy, and calibration issues, which hinder their effectiveness in reducing emissions.
Innovation Solution
A method and control device that utilize a gas sensor with electromechanical pumps operating in alternating phases to improve measurement accuracy by temporarily allowing gas components to accumulate, enabling higher current recordings and minimizing interference from other components, thereby enhancing the determination of low concentration gas components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the second electromechanical pump operates continuously to remove oxygen from the cavity, then the measurement speed is improved, but the measurement precision deteriorates due to inability to accumulate sufficient gas components for accurate measurement of low concentrations
Solution Approach 1:
The second electromechanical pump operates in periodic cycles, alternating between an active phase (pumping out oxygen) and an inactive phase (allowing gas components to accumulate). This periodic operation enables the system to accumulate sufficient first gas component (NOx) in the cavity during the inactive phase, thereby improving measurement precision for low concentrations while maintaining reasonable measurement speed through the structured pumping cycles.
2Loss of time
If the second electromechanical pump operates continuously, then the response time is reduced, but the current recording accuracy deteriorates due to insufficient accumulation of gas components
Solution Approach 1:
The pump operates periodically with defined active and inactive phases, allowing gas components to accumulate during the inactive phase before measurement. This ensures sufficient concentration for accurate current recording while maintaining a structured response time framework, resolving the contradiction between response time and measurement accuracy.
Solution Approach 2:
During the inactive phase of the periodic cycle, the system preliminarily accumulates the first gas component (NOx) in the cavity before the measurement phase begins. This preliminary accumulation ensures that when measurement occurs, sufficient gas component concentration is present for accurate current recording, thereby improving measurement precision without excessive delay.
3Measurement precision
If diffusion control members are manufactured with tight tolerances to ensure consistent diffusion, then the measurement precision is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The periodic operation of the second electromechanical pump creates controlled phases where gas components can accumulate to measurable concentrations. This operational control compensates for variations in diffusion control member performance, allowing acceptable measurement precision to be achieved without requiring extremely tight manufacturing tolerances on the diffusion control members.
Solution Approach 2:
The system changes the operational parameters of the second electromechanical pump (switching between active and inactive phases) to optimize measurement conditions. By controlling the timing and duration of pumping cycles, the system can achieve accurate measurements of low gas component concentrations without relying solely on precise diffusion control member manufacturing.
4Ease of operation
If the pump operates continuously to maintain steady-state conditions, then the operational simplicity is improved, but the ability to measure low concentrations deteriorates due to insufficient gas component accumulation
Solution Approach 1:
The system employs periodic pumping cycles with clearly defined active and inactive phases. This structured periodic operation maintains relative simplicity in control logic while enabling gas component accumulation during the inactive phase, thereby improving the ability to measure low concentrations without excessive operational 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
The method and control device enhance the accuracy of gas component concentration measurements, particularly for low concentrations, by optimizing pump operations and current recordings, facilitating reliable measurements across a wide range of concentrations.
Implementation Method 1
a first electromechanical pump formed by a first pair of electrodes arranged on opposing sides of a first wall portion of the cavity. By applying a voltage between the electrodes of the first pair of electrodes, a potential difference over the solid electrolyte is formed which in turn may cause a flow of oxygen ions out of the cavity through the solid electrolyte
Implementation Method 2
a second electromechanical pump formed by a second pair of electrodes arranged on opposite sides of a second wall portion. Said second wall portion is arranged downstream of the first wall portion as seen in relation to the space from which the gas to be analyzed is contained. The second electromechanical pump functions in the same way as the first electromechanical pump
Implementation Method 3
The current in the solid electrolyte, resulting from the applied voltage, is proportional to the amount of oxygen transported through the solid electrolyte and hence the concentration of oxygen in the gas originally contained in the cavity
Implementation Method 4
The cavity is configured to be in fluid communication with a space containing the gas via an inlet and a diffusion control member of the gas sensor. The purpose of the diffusion control member is to control the diffusion of gas into the cavity
Data Source
AI summary
A control device and a method for determining a concentration of a gas component, wherein a gas sensor is used. The gas sensor comprises a first electromechanical pump arranged at a first solid electrolyte membrane, and a second electromechanical pump arranged at a second solid electrolyte member. The method comprises operating the first electromechanical pump continuously and operating the second electromechanical pump in a plurality of phase pairs, each pair comprising a first and a second phase. The second electromechanical pump is in a deactivated state during the first phase and in an activated state during the second phase. A current in the second solid electrolyte membrane during the second phase is recorded, and the concentration of the gas component is determined based on said current. An exhaust gas treatment system and a vehicle are also disclosed.