Electrochemical Reactor Current Control for NOx Removal

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Solution Overview

Problem

The performance of an electrochemical reactor in removing NOX is compromised when the concentration of water molecules at the anode layer decreases, leading to a reduction in proton generation and subsequent NOX removal efficiency, especially when the current flow is high and water molecules are scarce.

Innovation Solution

An electrochemical reactor with a current control device that reduces the current flowing through the anode and cathode layers when water molecules are in short supply, integrated into an internal combustion engine's exhaust passage, allowing for fuel cut control and air-fuel ratio adjustments to manage water molecule availability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the current flowing through the anode layer and cathode layer is increased to enhance NOX removal, then the NOX removal rate increases, but the amount of water molecules held at the anode layer decreases rapidly leading to reduced performance

Engineering Contradiction:
ImproveNOX removal rateVSAvoidNOX removal performance stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies dynamics by making the current flow adjustable rather than fixed. The current control device dynamically adjusts the current magnitude based on real-time detection of water molecule amounts at the anode layer, allowing the system to adapt between high productivity modes (when water is abundant) and protective modes (when water is scarce), thus resolving the contradiction between maximizing NOX removal and maintaining performance stability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback through a detection device that continuously monitors the amount of water molecules at the anode layer and feeds this information to the current control device. This closed-loop feedback mechanism allows the system to automatically adjust current flow based on actual water availability, preventing the depletion of water molecules while maintaining effective NOX removal performance

Inventive Principle:
Principle #23Feedback

2Productivity

If a large current flows through the anode layer and cathode layer to remove NOX, then more protons are generated, but a large amount of protons are released into the exhaust gas as hydrogen molecules without contributing to NOX removal

Engineering Contradiction:
ImproveNOX removal efficiencyVSAvoidproton utilization efficiency
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies partial action by limiting the current flow to only the necessary amount required for effective NOX removal, rather than applying excessive current that would generate unnecessary protons. The current control device adjusts the current magnitude based on actual NOX removal needs and water molecule availability, preventing the generation of excess protons that would be wasted as hydrogen gas, thus improving proton utilization efficiency while maintaining NOX removal productivity

Inventive Principle:
Principle #16Partial or excessive action

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 suppresses the generation of non-contributory protons, maintaining NOX removal performance even with decreased water molecules at the anode layer, ensuring consistent NOX reduction efficiency.

Implementation Method 1

a proton conductive solid electrolyte layer

Methodology Applied
Scientific EffectProton conduction: Conduction (electrical)

Implementation Method 2

water molecules are broken down on the anode layer whereby protons and oxygen are generated

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 3

the NO X reacts with the protons on the cathode layer whereby nitrogen and water molecules are generated

Methodology Applied
Scientific EffectElectrochemical reduction: Redox Reactions

Data Source

PatentEP3505730B1Electrochemical reactor
Publication Date: 2020.08.12 TOYOTA JIDOSHA KK
  • EP3505730B1 patent drawingFigure 1
  • EP3505730B1 patent drawingFigure 2~3
  • EP3505730B1 patent drawingFigure 4

AI summary

An electrochemical reactor 70 is provided with a proton conductive solid electrolyte layer 75; an anode layer 76 arranged on the surface of the solid electrolyte layer and able to hold water molecules; a cathode layer 77 arranged on the surface of the solid electrolyte layer; and a current control device 73 controlling a current flowing through the anode layer and the cathode layer. The current control device reduces the current flowing through the anode layer and the cathode layer, when the water molecules held in the anode layer become smaller in amount.