Engine Exhaust Gas Temperature Control via Cylinder Group Routing
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Solution Overview
Problem
Current engines with EGR systems face challenges in maintaining exhaust gas temperature within a desired range, especially as emission control requirements become more stringent, necessitating higher EGR gas percentages, which existing methods struggle to manage effectively.
Innovation Solution
The implementation of a method where exhaust gas from a first group of cylinders is routed to an EGR system and an exhaust system, while exhaust gas from a second group of cylinders is routed directly to the exhaust system, with a valve-controlled connection between the two systems to regulate temperature, allowing for precise control of exhaust gas flow and characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If higher percentages of EGR gas are used to meet emission control requirements, then NOx production is reduced, but exhaust gas temperature control becomes difficult to maintain within desired range
Solution Approach 1:
The engine cylinders are divided into two groups: a first group whose exhaust gas is routed to the EGR system, and a second group whose exhaust gas is routed directly to the exhaust system. This segmentation allows independent control of EGR gas temperature and composition, enabling temperature management while maintaining high EGR percentages for NOx reduction
Solution Approach 2:
A valve-controlled connection is introduced as an intermediary between the EGR system and the exhaust system. This intermediary component enables regulated flow of exhaust gas between the two systems, providing precise control over exhaust gas temperature and composition to maintain desired temperature ranges while achieving high EGR percentages
2Object-generated harmful factors
If higher EGR gas percentages are recirculated to reduce NOx, then emission control improves, but exhaust gas temperature may drop below desired range
Solution Approach 1:
The exhaust gas streams from the first group of cylinders (routed through EGR) and the second group of cylinders (routed directly to exhaust system) are merged downstream of the turbine. This merging combines cooler EGR gas with hotter direct exhaust gas, maintaining exhaust gas temperature within desired ranges while achieving high overall EGR percentages for effective emission control
3Object-generated harmful factors
If exhaust gas is routed through EGR system to reduce emissions, then NOx production decreases, but additional equipment and system complexity is required
Solution Approach 1:
The valve-controlled connection serves multiple functions: it regulates flow between EGR and exhaust systems, controls exhaust gas temperature, and enables high EGR percentages. This multi-functionality reduces the need for additional dedicated equipment, managing system complexity while achieving effective emission control
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 allows for maintaining engine exhaust gas temperature within a desired range, optimizing the operation of aftertreatment components and reducing the need for additional fuel for regeneration, while also enabling the use of smaller EGR system components and lower O2 levels, thus enhancing emission control and operational efficiency.
Implementation Method 1
exhaust gas from a first group of cylinders comprising at least one cylinder is routed to at least one of an EGR system and an exhaust system. Exhaust gas from a second group of cylinders comprising at least one cylinder is routed to the exhaust system. Routing of the exhaust gas is from the first group of cylinders between the EGR system and the exhaust system to maintain a temperature of engine exhaust gas within a desired range.
Data Source
AI summary
In a method of maintaining temperature of engine exhaust gas from cylinders of a multi-cylinder engine (23) with a desired range, exhaust gas from a first group of cylinders (25) including at least one cylinder is routed to at least one of an EGR system (53) and an exhaust system (41). Exhaust gas from a second group of cylinders (27) including at least one of the cylinders is routed to the exhaust system (41). Routing of the exhaust gas from the first group of cylinders between the EGR system and the exhaust system is controlled to maintain a temperature of engine exhaust gas within a desired range. An engine (23), a control system (69), and a controller (71), as well as an exhaust gas mixture, are also disclosed.