Exhaust Conduit for Methane Oxidation in Diesel Engines
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Solution Overview
Problem
Internal combustion piston engines, particularly gas-diesel and dual-fuel engines, face challenges in reducing methane slip into the atmosphere due to its concentration in dead volumes within the cylinder, which existing technologies struggle to address effectively, especially with low methane concentrations in exhaust gases and high oxidation temperature requirements.
Innovation Solution
An arrangement is implemented that includes a conduit with strategically positioned inlets near the exhaust valve, connected to the turbocharger unit, which directs exhaust gases with higher methane concentrations to an oxidation catalyst unit for processing, optimizing the flow to enhance methane oxidation by controlling the flow based on exhaust valve positions and using a waste gate to manage pressure and air coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional oxidation system processes the entire exhaust gas stream, then methane oxidation can be achieved, but the system becomes large and inefficient due to low methane concentration in the diluted exhaust gas
Solution Approach 1:
The exhaust gas flow is segmented into two separate paths: a main exhaust stream that goes directly to the atmosphere, and a separated portion that is diverted through the oxidation catalyst. This segmentation allows the oxidation system to process only the portion of exhaust gas containing unburned methane, rather than treating the entire diluted exhaust stream, thereby reducing system size while maintaining oxidation effectiveness
Solution Approach 2:
The invention extracts or separates the unburned fuel-containing portion of the exhaust gas from the main exhaust stream using a dedicated flow path with strategically positioned inlets near the exhaust valve. This extracted portion is then directed to the oxidation catalyst, allowing the system to target and treat only the relevant component (unburned methane) without processing the entire exhaust volume, thus improving efficiency and reducing system dimensions
2Volume of moving object
If the oxidation catalyst is placed on-engine, then the system is compact, but it increases engine complexity and requires precise integration with exhaust ports
Solution Approach 1:
The invention introduces an intermediary conduit system with strategically positioned inlets that acts as a mediator between the exhaust valve area and the oxidation catalyst. This intermediary structure facilitates the separation and redirection of the unburned fuel-containing exhaust portion to the catalyst, which can then be positioned off-engine, simplifying integration while maintaining system compactness through optimized flow paths
3Ease of manufacture
If inlets are positioned far from the exhaust valve, then the system is easier to manufacture, but methane concentration in the oxidizing unit decreases
Solution Approach 1:
The invention applies local quality by positioning the inlet openings at specific locations within the exhaust port where the gas flow characteristics and methane concentration are optimal. The inlets are strategically placed near the exhaust valve in regions where unburned fuel accumulates, ensuring high methane concentration in the diverted stream while maintaining manufacturability through standardized positioning relative to the exhaust valve geometry
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 solution increases methane concentration in the oxidizing unit, reduces methane slip into the atmosphere, and results in a more efficient and compact oxidation system that can be placed off-engine, with the ability to bypass the oxidizing unit if needed, improving overall engine efficiency.
Implementation Method 1
a fuel processing unit for oxidation of fuel material in the exhaust gas of the engine
Data Source
AI summary
Invention relates to an arrangement for reducing fuel material slip to the atmosphere in an internal combustion piston engine with at least two cylinders (14) and at least one turbo charger unit (28), and an exhaust gas system (24) arranged to connect a combustion chamber of each cylinder of the engine controllably by means of an exhaust valve or valves (23) to the atmosphere via a turbine section (28.2) of the at least one turbo charger unit, the arrangement comprising a fuel processing unit (34) for oxidation of fuel material in the exhaust gas of the engine the arrangement comprises a body (102) through which a conduit (32) is arranged to extend into the vicinity of the exhaust valve at least partly via the exhaust gas system, and the fuel processing unit is arranged in connection with to the conduit (32). Invention relates also to method of upgrading an internal combustion piston engine.