Exhaust Heating Device With Two-Zone Combustion
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Solution Overview
Problem
Existing heating devices for exhaust systems of internal combustion engines often result in incomplete fuel combustion, leading to unburned fuel entering the exhaust duct and causing temperature fluctuations or increased pollutant emissions, and are inefficient in achieving the catalyst's operating temperature quickly.
Innovation Solution
A heating device with a combustion chamber connected to an exhaust duct and a fan, featuring a fuel injector and spark plug, and a design that includes a mixing chamber and a secondary tubular body to ensure complete combustion and efficient heat transfer, using tangential air flow and swirling motion to stabilize combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high quantity of fuel is injected to generate large quantity of heat, then the heating efficiency is improved, but incomplete combustion occurs leading to unburned fuel in exhaust duct
Solution Approach 1:
The combustion chamber is divided into a central zone and an annular peripheral zone with separate air supply paths. The central zone receives fuel and primary air for initial combustion, while the peripheral zone receives secondary air to complete the combustion of any unburned fuel, ensuring complete combustion even at high fuel injection quantities.
Solution Approach 2:
Different regions of the combustion chamber are provided with different air-fuel mixture qualities. The central zone has a richer mixture for rapid heat generation, while the peripheral zone has a leaner mixture with excess oxygen to ensure complete combustion and oxidize any unburned hydrocarbons before exhaust.
2Speed
If fuel combustion is intensified to raise catalyst temperature quickly, then the heating speed is improved, but temperature fluctuations occur in exhaust duct
Solution Approach 1:
The combustion system maintains continuous and stable burning through optimized air-fuel mixing and a two-zone combustion approach. The central zone provides continuous heat generation while the peripheral zone ensures complete combustion, preventing flame instability and temperature fluctuations in the exhaust duct.
3Ease of manufacture
If simple combustion chamber design is used, then manufacturing cost is reduced, but combustion stability and completeness deteriorate
Solution Approach 1:
The combustion chamber is segmented into central and peripheral zones with distinct air supply paths. This segmentation is achieved through simple structural elements like a central fuel injector and peripheral air holes in the combustion chamber wall, providing complex combustion functionality without excessive manufacturing complexity.
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 in all conditions, maintains stable exhaust duct temperature, and efficiently raises the catalyst's operating temperature while being cost-effective and easy to manufacture.
Implementation Method 1
a spark plug, which cyclically gives off sparks for igniting the air-fuel mixture so as to obtain the combustion that heats the air
Implementation Method 2
a spark plug, which cyclically gives off sparks for igniting the air-fuel mixture
Implementation Method 3
a fan which generates an air flow which flows through the combustion chamber
Implementation Method 4
generates a (very) hot air flow which flows through the catalyst
Implementation Method 5
efficiently raises the catalyst's operating temperature
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A heating device (6) for an exhaust system (1) of an internal combustion engine (2) and having: a main tubular body (12), which contains a combustion chamber (7) delimited by a first base wall (14) and by a second base wall (15), which are opposite one another; a fuel injector (9) configured to inject fuel; an inlet opening (19), which can be connected to a fan (8) to receive an air flow, which is directed to the combustion chamber (7) and gets mixed with fuel; a secondary tubular body (23) which is arranged inside the main tubular body (12) and inside the combustion chamber (7) and has a side wall (24), which is arranged at a given distance from the side wall (16) of the main tubular body (12) so as to divide an initial part of the combustion chamber (7) into a central zone (25), which is located inside the secondary tubular body (23), and an annular peripheral zone (26), which is located around the secondary tubular body (23).