Heated Injector and Grid for Exhaust Gas Post-Treatment
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Solution Overview
Problem
Existing exhaust gas post-treatment devices face challenges in rapidly reaching the required operating temperature during transitional phases, such as engine start-up, which prolongs the heating duration and reduces nitrogen oxide reduction efficiency in purification members.
Innovation Solution
A device with a heated reducing agent injector and an electrically heated grid or foam heating element, strategically positioned between the injector and the purification member, utilizes thermal and electrical activation based on exhaust gas temperature to enhance mixing and heating efficiency, including the use of flash boiling technology for the injector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heating element is used to heat the purification member during transitional phases, then the purification member reaches operating temperature faster, but the duration of the transitional heating phase is still prolonged
Solution Approach 1:
The reducing agent is pre-heated in a separate heating chamber before being injected into the exhaust gas flow. This preliminary heating action ensures that the reducing agent reaches optimal temperature for immediate chemical reaction upon contact with the exhaust gases, eliminating the need for prolonged heating of the entire purification member and significantly reducing the transitional phase duration.
Solution Approach 2:
The heating function is segmented into two independent zones: a dedicated heating chamber for pre-heating the reducing agent, and the purification member for the actual chemical reaction. This segmentation allows the reducing agent to be heated separately and efficiently before injection, rather than heating the entire purification member assembly, thereby reducing the overall heating time and energy consumption.
2Productivity
If the injector is positioned close to the purification member, then the reducing agent is injected efficiently, but the surface area of the heating element receiving the reducing agent is reduced
Solution Approach 1:
The injector is positioned at the end of an extended axis that protrudes into the exhaust gas flow, creating a spatial arrangement where the injector tip is close to the purification member for efficient injection, while the heating element is positioned perpendicular to this axis with its surface facing the incoming reducing agent. This dimensional arrangement allows both requirements to be satisfied simultaneously: close injection distance and large heating surface area.
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 configuration reduces the transitional heating phase duration and improves nitrogen oxide reduction efficiency by ensuring effective mixing and homogenization of exhaust gases with the reducing agent, even at lower temperatures, thereby accelerating the purification member's temperature reach and maintaining high conversion efficiency.
Implementation Method 1
the grid or foam is metallic and electrically heated by Joule effect by using at least one electrode
Implementation Method 2
the injector is electrically heated by using flash boiling technology
Data Source
AI summary
A device for the post-treatment of the exhaust gas of an internal combustion engine comprises a conduit defining a passage for the flow of the exhaust gas and, from upstream to downstream of the conduit, an injector arranged to inject a reducing agent into the flow passage, and a purifying member. The injector is heated to heat the reducing agent prior to injection. The device further comprises a heating element arranged between the injector and the purifying member.