Engine EGR Control Apparatus Dew-Point Management
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Solution Overview
Problem
Conventional control apparatuses for internal combustion engines face challenges in quickly starting EGR control when shifting from an EGR stop region to an EGR execution region, leading to prolonged states where EGR control cannot be performed, and fail to properly suppress condensed water generation in intake air, resulting in degraded fuel economy.
Innovation Solution
A control apparatus that includes a supercharging device, an EGR device, and an intake air cooling system with a temperature-increasing device to control coolant temperatures, ensuring intake air exceeds the dew-point temperature during EGR execution and allowing quick transition from EGR stop to execution regions, while preventing condensed water formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If engine coolant is introduced into the intercooler cooling circuit to increase outlet temperature, then condensed water generation is suppressed, but EGR control cannot be quickly started when shifting from EGR stop region to execution region
Solution Approach 1:
The control apparatus performs preliminary heating of the intercooler cooling circuit using engine coolant before EGR control is activated. By advancing the heating action to occur during the transition period, the system ensures that when EGR control starts, the intercooler is already at the appropriate temperature to prevent condensed water formation, thus eliminating the time delay penalty.
Solution Approach 2:
The system dynamically adjusts the cooling circuit configuration based on operating conditions. It transitions from a state where engine coolant is not introduced to a state where it is introduced, and vice versa, depending on whether the engine is in EGR execution region or stop region. This dynamic adaptation allows optimal performance across different operating conditions without permanent compromise.
2Loss of energy
If EGR control is quickly started when shifting from EGR stop region to execution region, then fuel economy is improved, but condensed water may be generated in intake air
Solution Approach 1:
The system performs preliminary temperature preparation of the intercooler cooling circuit before EGR control activation. By pre-heating the coolant and intercooler during the transition phase, the system ensures that when EGR control begins, the temperature conditions are already favorable for preventing condensed water, thus enabling immediate EGR operation without fuel economy penalty.
Solution Approach 2:
The control apparatus changes the temperature parameter of the cooling circuit by introducing engine coolant with higher temperature. This parameter change raises the intercooler outlet temperature above the dew point, preventing condensed water formation while allowing EGR control to operate immediately for improved fuel economy.
3Object-affected harmful factors
If outlet temperature of intercooler is controlled to be higher than dew-point temperature during EGR execution, then condensed water is suppressed, but intake air temperature is increased
Solution Approach 1:
The system applies local quality control by selectively heating only the intercooler cooling circuit with engine coolant during specific transition periods, rather than uniformly increasing temperature throughout the entire cooling system. This localized thermal management prevents condensed water formation at the intercooler outlet while minimizing the impact on overall intake air temperature.
Solution Approach 2:
The control apparatus applies periodic or conditional heating action only during the transition from EGR stop region to execution region. During normal EGR execution, the system maintains appropriate temperature control without continuous engine coolant introduction, thus preventing condensed water formation only when necessary while minimizing overall intake air temperature increase.
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
Enables rapid initiation of EGR control and effective suppression of condensed water generation, thereby enhancing fuel economy and maintaining engine performance.
Implementation Method 1
intake air increased in temperature by the supercharging operation is cooled by the intercooler
Implementation Method 2
a temperature-increasing device to control coolant temperatures, ensuring intake air exceeds the dew-point temperature during EGR execution
Data Source
AI summary
A control apparatus 1 for the engine includes an ECU. When the operating region of the engine is in the EGR execution region B, the ECU performs the EGR control (step 2), and performs first coolant temperature control for controlling an IC coolant temperature TWic such that the temperature of intake air passing through an intercooler exceeds a dew-point temperature (step 14). Further, in a case where the operating region of the engine is in the EGR stop region C, the ECU performs second coolant temperature control for controlling the IC coolant temperature TWic such that the temperature of intake air having passed through the intercooler exceeds the dew-point temperature, assuming that the operating region of the engine has shifted to the EGR execution region B (step 17).