Exhaust Gas Recirculation Line Heating for Cold Start Condensation
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Solution Overview
Problem
Internal combustion engines face challenges in implementing exhaust gas recirculation after a cold start due to condensation issues in the exhaust gas recirculation line, leading to delayed activation of exhaust gas recirculation and increased nitrogen oxide emissions.
Innovation Solution
A method that utilizes the generator to operate an electrical heating device during overrun operation, heating the exhaust gas and guiding it through the exhaust gas recirculation line to preheat the system, thereby preventing condensation and enabling quicker exhaust gas recirculation, even during cold starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas recirculation is activated immediately after cold start, then nitrogen oxide emissions can be reduced, but condensation of moisture in the exhaust gas recirculation line occurs causing damage to components
Solution Approach 1:
The heating device is activated before exhaust gas recirculation to preheat the exhaust gas recirculation line, preventing condensation from forming. This preliminary heating action ensures that when exhaust gas recirculation starts, the line temperature is already above the dew point, eliminating the condensation problem while enabling immediate EGR activation for emission reduction.
Solution Approach 2:
The heating device applies heat to the exhaust gas recirculation line in advance to counteract the cooling effect that would otherwise cause condensation. By preemptively heating the line, the system prevents the harmful condensation effect before it can occur, allowing safe immediate activation of exhaust gas recirculation.
2Temperature
If an electric heating device is integrated into the exhaust gas line or exhaust gas recirculation line, then the system can be heated during overrun operation, but additional energy consumption and device complexity are introduced
Solution Approach 1:
The electric heating device serves multiple functions: it heats the exhaust gas recirculation line during cold start to prevent condensation, and it also heats the exhaust gas during overrun operation to maintain temperature. By integrating a single heating device that performs both functions, the system avoids the complexity of separate heating systems while achieving multiple temperature control objectives.
Solution Approach 2:
The heating device utilizes electrical energy from the generator during overrun operation, a time when the engine is already producing excess energy. This self-service approach uses otherwise wasted energy resources to maintain exhaust gas temperature, reducing the need for additional dedicated energy input while achieving temperature control.
3Temperature
If exhaust gas is cooled using a cooler, then fresh gas temperature is controlled to prevent thermal overload, but the exhaust gas recirculation line cools down causing condensation after cold start
Solution Approach 1:
The system dynamically adjusts the operation of the exhaust gas cooler based on engine operating conditions. During cold start, the cooler is deactivated or operated at reduced capacity to allow the exhaust gas recirculation line to maintain higher temperature and avoid condensation. Once the engine is warmed up, the cooler is activated to prevent thermal overload of the fresh gas. This dynamic control resolves the contradiction between preventing condensation and controlling fresh gas temperature.
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 method allows for the rapid activation of exhaust gas recirculation, reducing nitrogen oxide emissions and preventing thermal overload, while also utilizing kinetic energy to power the heating device, thus enhancing engine efficiency and reducing fuel consumption.
Implementation Method 1
the heating device is operated with energy provided by the generator and exhaust gas heated by means of the heating device
Implementation Method 2
exhaust gas heated by means of the heating device...is guided partially or completely via the exhaust gas recirculation line
Implementation Method 3
heating the exhaust gas and guiding it through the exhaust gas recirculation line to preheat the system
Implementation Method 4
Exhaust gas cooling using an exhaust gas cooler can be achieved either directly or indirectly through ambient air. Indirect cooling involves transferring heat energy from the exhaust gas to a liquid coolant
Data Source
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AI summary
A method for operating an internal combustion engine comprising an internal combustion engine 1, a generator 24 coupled to the internal combustion engine 1, a fresh gas stream 5, an exhaust gas stream 8, an exhaust gas recirculation line 19 branching off from the exhaust gas stream 8 and leading into the fresh gas stream 5, and at least one electric heating device 23 integrated into the exhaust gas stream 8 or into the exhaust gas recirculation line 19, is characterized in that during overrun operation of the internal combustion engine 1, the heating device 23 is operated with energy provided by the generator 24 and exhaust gas heated by means of the heating device is partially or completely routed via the exhaust gas recirculation line 19.