Modular SCR Canisters for Compact Diesel Exhaust Packaging
Solution Overview
Problem
Existing SCR systems for diesel engines face challenges in compactness and maintenance accessibility due to the size and layout of components, which complicates packaging within vehicles and increases maintenance time and costs.
Innovation Solution
A compact SCR system design featuring a frame with removably attached canisters for the SCR catalyst and ammonia oxidation catalyst, connected by exhaust passages and end caps to ensure optimal mixing of exhaust gas and DEF/ammonia without increasing back pressure, allowing for easy maintenance and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple SCR system components (DOC, DPF, SCR catalyst, AMOx catalyst) are integrated into a single packaged unit, then the system becomes more compact and easier to install, but maintenance becomes more difficult and time-consuming
Solution Approach 1:
The SCR system is divided into separate modular components (DOC canister, DPF canister, SCR catalyst canister, AMOx catalyst canister) that are individually removable from the frame. Each canister can be accessed and serviced independently while maintaining a compact overall system configuration when assembled together.
2Area of stationary object
If SCR system components are made compact to fit within vehicle constraints, then packaging space is reduced, but maintenance accessibility and serviceability deteriorate
Solution Approach 1:
The system transitions from a fixed integrated configuration to a dynamic modular arrangement where canisters can be easily attached and detached from the frame. This allows the system to maintain a compact footprint during operation while becoming easily accessible during maintenance through simple removal of individual canisters.
3Device complexity
If DEF dosing unit is positioned to connect opposing ends of DOC and DPF components, then component integration is improved, but exhaust gas and DEF mixing efficiency may be compromised
Solution Approach 1:
An end cap serves as an intermediary component that connects the DOC canister and DPF canister while providing an optimized flow path for exhaust gas and DEF mixing. The end cap includes internal geometry designed to enhance turbulence and mixing efficiency between the exhaust gas from DOC and the DEF injected by the dosing unit.
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 system achieves a compact and accessible design for SCR systems that ensures optimal mixing of exhaust gases and DEF/ammonia, reducing back pressure and simplifying maintenance while maintaining effective NOx reduction.
Implementation Method 1
A SCR catalyst, which catalyses the reaction between the NOx and ammonia now in the exhaust passage to produce nitrogen and water
Implementation Method 2
An ammonia oxidation (AMOx) catalyst, which oxidises any ammonia remaining in the exhaust gas downstream of the SCR to ensure that significant amounts of ammonia do not 'slip' out into the atmosphere
Implementation Method 3
A diesel oxidation catalyst (DOC), which oxidises any hydrocarbons and carbon monoxide to produce carbon dioxide and water
Implementation Method 4
A hydrolysis catalyst, which hydrolyses the urea in the DEF in order to convert it to ammonia as efficiently as possible
Data Source
AI summary
A selective catalytic reduction (SCR) system for treating exhaust gas from a diesel engine is provided, along with a method of assembling such a system. The system comprises a frame, a SCR catalyst contained within a SCR canister, and an ammonia oxidation catalyst contained within an ammonia oxidation canister. Each of the SCR and ammonia oxidation canisters is removably attached to the frame.