Exhaust Heating Device with Segmented Combustion for Cold Start Emissions
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Solution Overview
Problem
Existing heating devices for internal combustion engine exhaust systems often fail to achieve complete fuel combustion, leading to unburnt fuel entering the exhaust duct and causing sudden, undesired temperature rises, which hampers the rapid heating of catalytic converters during cold start phases, resulting in high polluting emissions.
Innovation Solution
A heating device with a combustion chamber connected to the exhaust duct upstream of the catalytic converter, equipped with a fuel injector, spark plug, and a fan, utilizing a static mixer and optimized fuel injection to ensure complete combustion of fuel, preventing unburnt fuel from entering the exhaust duct, and featuring a control unit to manage operations efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large quantity of fuel is injected to generate high thermal power for rapid heating, then the heating efficiency is improved, but incomplete combustion occurs causing unburnt fuel to enter the exhaust duct and create harmful temperature spikes
Solution Approach 1:
The combustion chamber is divided into distinct zones: a primary combustion zone where fuel initially burns, and a secondary combustion zone where unburnt fuel continues to combust. This segmentation allows progressive combustion at different stages, ensuring complete burn even with high fuel injection rates.
Solution Approach 2:
The device pre-mixes fuel with air in a controlled manner before introducing it to the combustion chamber. The fan pre-circulates air through the chamber before fuel injection, and the injector distributes fuel uniformly, ensuring optimal mixing conditions are established before combustion begins, thereby preventing incomplete combustion.
2Ease of manufacture
If the heating device is made compact to reduce size and manufacturing cost, then ease of manufacture is improved, but the combustion chamber volume is reduced which may compromise combustion completeness
Solution Approach 1:
The fuel injector is positioned inside the combustion chamber rather than on the exterior. The spark plug is also integrated within the chamber structure. This nesting arrangement maximizes the effective combustion volume within a compact external footprint, maintaining reliable combustion while keeping the device small and easy to manufacture.
Solution Approach 2:
Multiple functional components are merged into a single integrated housing: the combustion chamber, fuel injector, spark plug, and air circulation system are combined into one compact unit. This merging reduces the overall device size and simplifies manufacturing while preserving the necessary combustion volume through efficient spatial arrangement.
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
Ensures complete fuel combustion, rapid heating of the catalytic converter, reducing polluting emissions during cold start phases, and is simple and economical to manufacture with high thermal power relative to its size.
Implementation Method 1
a spark plug, which cyclically produces sparks to ignite the air-fuel mixture in order to obtain the combustion that heats the air
Implementation Method 2
a fan, which generates an air flow flowing through the combustion chamber
Implementation Method 3
by burning fuel, generates a (very) hot air flow, which flows through the catalytic converter
Data Source
Figure 1
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Figure 3
AI summary
A heating device (6) for an exhaust system (1) of an internal combustion engine (2) and having: a tubular body (12), where a combustion chamber (7) is obtained on the inside; a fuel injector (9), which injects fuel into the combustion chamber (7); at least one inlet opening (18), which can be connected to a fan (8) so as to receive an air flow, which is directed to the combustion chamber (7) and gets mixed with the fuel; a feeding channel (21), which receives air from the inlet opening (18), surrounds an end portion of the fuel injector (9) and ends with a nozzle (22), which is arranged around an injection point of the fuel injector (9); and a spark plug (10), which is mounted through a side wall (16) of the tubular body (12) so as to trigger the combustion of a mixture of air and fuel. The fuel injector (9) is configured to spray at least 80% of the fuel against an inner surface (26) of the feeding channel (21).