Carbon-Fiber Immersion Heater for Faster DEF Tank Thawing
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Solution Overview
Problem
Current SCR systems for diesel engines rely on engine coolant to thaw frozen diesel exhaust fluid (DEF), which is slow and requires complex coolant lines, increasing cost and delaying system startup due to inadequate temperature control.
Innovation Solution
An electric immersion heater with a semi-conductive carbon fiber heating element encapsulated in a thermoplastic sheath is used to efficiently heat DEF tanks, allowing for faster thawing and eliminating the need for coolant lines by providing close temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If engine coolant is circulated through a copper coil in the DEF tank to thaw frozen DEF, then the DEF tank can be heated, but the thawing process is slow and the system complexity increases due to required coolant lines
Solution Approach 1:
The invention extracts the heating function from the engine coolant system and creates an independent electric heating element that can operate autonomously. The heating element is directly immersed in the DEF tank, eliminating the need for coolant circulation through copper coils and enabling rapid thawing without being constrained by engine coolant temperature.
Solution Approach 2:
The invention replaces the mechanical coolant circulation system with an electric heating element. Instead of using the engine coolant pump and circulation system to transfer heat to the DEF tank, an electric heating element directly converts electrical energy to thermal energy within the DEF tank, significantly reducing thawing time and system complexity.
2Temperature
If engine coolant is circulated through a copper coil in the DEF tank, then heating can be provided, but the system cost and complexity increase due to coolant lines
Solution Approach 1:
The heating function is extracted from the engine coolant system and implemented as an independent electric heating element. This eliminates the need for coolant lines running to and from the DEF tank, simplifying the overall system architecture while maintaining the essential heating capability.
Solution Approach 2:
The electric heating element is self-contained and does not require the engine coolant system to function. It can operate independently to heat the DEF tank, making the system self-sufficient for this specific function and eliminating the need for complex interconnections with the coolant system.
3Temperature
If engine coolant is used to heat the DEF tank, then heating is provided, but temperature control is inadequate and startup is delayed
Solution Approach 1:
The system incorporates a temperature sensor that continuously monitors the DEF tank temperature and provides feedback to the control unit. The control unit adjusts the power supplied to the heating element based on this feedback, maintaining precise temperature control and preventing both overheating and inadequate heating that would occur with passive coolant circulation.
Solution Approach 2:
The heating system transitions from a static, passive coolant circulation approach to a dynamic, actively controlled electric heating system. The control unit can rapidly adjust heating power in response to temperature changes, enabling precise temperature management and rapid response to startup conditions.
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
The immersion heater enables faster and more efficient thawing of DEF, reducing startup delays and simplifying the system by eliminating coolant lines, thus enhancing the effectiveness of emissions control in diesel engines.
Implementation Method 1
The heating element may be a semi-conductive thermoplastic material, such as a thermoplastic polymer loaded with conductive carbon fiber
Implementation Method 2
The encapsulation material may be a rubber or thermoplastic material with sufficient chemical resistance to be immersed in a reservoir of fluid subject to freezing or thickening at low temperatures
Data Source
Figure 1~3
Figure 4~12
AI summary
An immersion heater including an encapsulated, semi -conductive, heating element. The heating element may be a non-metallic, carbon-based material in the form of a monofilament, a yarn or bundle of semi-conductive fibers which may be twisted, braided fibers or yarns, or the like. The encapsulation may be in the form of a tube of one or more layers of encapsulation material(s) with the heating element inserted therein. Alternately, the heating element may be thermoplastic with semi- conductive carbon additive, and the heating element may be coated with one or more external layers of insulating encapsulation material(s). The encapsulation material may be a rubber or thermoplastic material with sufficient chemical resistance to be immersed in a reservoir of fluid subject to freezing or thickening at low temperatures, such as DEF. The heater may be thermoformed into a predetermined fixed shape.