Spiral Exhaust Gas Heating Unit Axial Offset
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Solution Overview
Problem
Existing exhaust gas heating arrangements for internal combustion engines are inefficient in quickly bringing exhaust gas treatment units to operating temperature, especially during the starting phase, which hampers the reduction of pollutant emissions.
Innovation Solution
A spirally wound exhaust gas heating arrangement with a jacket heating element and insulating material, featuring a radially overlapping coil structure and a heat transfer surface formation that increases the surface area for heat transfer, is positioned in a way that the radially inner coil end is axially offset relative to the outer coil end, enhancing heat input into the exhaust gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional heating arrangement with a planar coil structure is used, then the structure is simple, but the heat transfer efficiency to exhaust gas is insufficient
Solution Approach 1:
The patent transforms the conventional planar coil structure into a three-dimensional spatial configuration where the coil is radially offset along the axial direction. This dimensional change allows the heating element to extend into the exhaust gas flow path, increasing the effective heat transfer surface area and improving thermal efficiency without significantly complicating the overall structure.
Solution Approach 2:
The heating arrangement is positioned upstream of the exhaust gas treatment unit, allowing preheating of the exhaust gas before it reaches the catalyst. The radial offset configuration ensures that heat is transferred to the exhaust gas flow in advance, preparing it for efficient catalytic conversion and reducing the time required to reach operating temperature.
2Area of stationary object
If the heating unit is extended axially with spiral winding, then the heat transfer surface area increases, but the structural complexity increases
Solution Approach 1:
The patent employs a spiral winding configuration for the heating coil, replacing straight or simple curved sections with a continuous helical structure. This curvature allows the heating element to pack more surface area into a compact axial space, maximizing heat transfer area while maintaining a relatively simple manufacturable form.
Solution Approach 2:
The heating coil is arranged in a nested spiral pattern where successive turns of the coil are radially offset from each other along the axial direction. This nesting approach allows multiple heating sections to occupy overlapping radial projections while being distributed axially, effectively multiplying the heat transfer surface area within a compact volume.
3Productivity
If radially adjacent coil sections overlap, then heat transfer efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent deliberately introduces asymmetry into the coil structure by applying a radial offset between adjacent coil sections along the axial direction. This asymmetric arrangement creates controlled overlapping regions where heat transfer is enhanced, while the offset pattern can be designed to accommodate typical manufacturing tolerances rather than requiring perfect symmetry and alignment.
Solution Approach 2:
The radial offset is applied selectively to specific sections of the coil rather than uniformly throughout. This allows local optimization of heat transfer in critical regions where exhaust gas flow and temperature conditions demand enhanced heating, while other sections can be manufactured with standard precision requirements.
4Loss of time
If the heating arrangement is positioned upstream of the exhaust gas treatment unit, then the exhaust gas can be preheated, but the space requirement increases
Solution Approach 1:
The patent utilizes the radial dimension by offsetting coil sections radially from the central axis, allowing the heating elements to extend into the exhaust gas flow path without requiring additional axial length. This three-dimensional positioning enables preheating functionality while maintaining a compact overall system length.
Solution Approach 2:
The heating unit is integrated into the exhaust gas guide housing structure, with the spiral wound heating element positioned within the existing housing boundaries. This merging of the heating function into the existing exhaust system architecture allows preheating capability to be added without proportionally increasing the overall system length or volume.
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 configuration ensures efficient heat transfer to the exhaust gas, quickly heating the exhaust gas treatment units, thereby reducing pollutant content in the exhaust gas and shortening the time for the exhaust gas treatment units to reach operational temperature for catalytic reactions.
Implementation Method 1
By applying an electrical voltage to the connection ends of the heating conductor, it is excited and releases heat to the outside via the jacket
Implementation Method 2
releases heat to the outside via the jacket
Implementation Method 3
a heat transfer surface formation is provided in the form of a heat transfer element surrounding the jacket in a helically wound manner. This heat transfer element increases the surface over which heat can be given off to the exhaust gas flowing around such an exhaust gas heating unit
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An exhaust gas heating arrangement comprises a heating unit (12) with a jacket heating element (28) having a jacket (30) and at least one heating conductor (32) running in the jacket and surrounded by insulating material, wherein the heating unit (12) is wound spirally around a longitudinal center axis (L), wherein a radially inner winding end region (46) of the heating unit (12) is offset relative to a radially outer winding end region (48) of the heating unit (12) in the direction of the longitudinal center axis (L).