EGR Cooler Coolant Flow Control for Cold Start Heating
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Solution Overview
Problem
At cold start of an internal combustion engine, the EGR cooler reduces the temperature of cooling water, which impairs the start-up performance of the air heating function and delays the activation of the EGR system.
Innovation Solution
A cooling device with a flow rate adjusting mechanism and control system that shuts off coolant supply to the EGR cooler until the EGR system is activated, allowing coolant to flow only to the air conditioning heater when the coolant temperature is below a predetermined level, and then to both the EGR cooler and heater when the temperature rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the EGR cooler continuously cools the cooling water at cold start, then the EGR system can be activated, but the start-up performance of the air heating function deteriorates
Solution Approach 1:
The patent implements dynamic control of the cooling water flow distribution based on engine operating conditions. The control unit dynamically switches between different flow paths: at cold start, cooling water is directed to the air conditioning heater to raise temperature, while after activation, flow is directed to the EGR cooler. This dynamic flow management resolves the contradiction by adapting the cooling system's behavior to different operational phases.
Solution Approach 2:
The patent applies preliminary action by pre-heating the cooling water through the air conditioning heater before activating the EGR system. This ensures that when the EGR system needs to be activated, the cooling water has already reached a sufficient temperature, preventing the contradiction from occurring in the first place.
2Reliability
If the EGR cooler cools the cooling water at cold start, then the EGR system can operate, but the time to activate the EGR system increases
Solution Approach 1:
The control system dynamically manages the cooling water flow distribution based on real-time engine conditions. During cold start, the system prioritizes heating by directing flow to the air conditioning heater, then transitions to EGR cooling mode once activation conditions are met. This dynamic switching reduces activation time by not continuously cooling the water before activation is needed.
Solution Approach 2:
The patent implements periodic control where the cooling water flow path is switched at specific intervals or conditions: initially directing flow to the heater, then switching to the EGR cooler once activation criteria are satisfied. This periodic switching pattern optimizes both heating performance and activation timing.
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 improves the start-up performance of the air heating function and reduces the time to activate the EGR system at cold start.
Implementation Method 1
the EGR cooler removes heat from the cooling water so that the cooling water that has been used for cooling of the internal combustion engine and has increased in temperature again decreases in temperature
Implementation Method 2
the start-up performance of the air heating function of the air conditioning heater provided by heat exchange between air for air-conditioning and the cooling water
Data Source
AI summary
At cold start of an internal combustion engine having an EGR system configured to recirculate, to an intake system, a portion of exhaust gas from the internal combustion engine, supply of a coolant to an EGR cooler and an air conditioning heater which are provided in a coolant circuit for circulating the coolant through the internal combustion engine and an outside thereof is shut off, when a temperature of the coolant is less than a predetermined temperature, and supply of the coolant to the air conditioning heater is allowed and supply of the coolant to the EGR cooler is shut off until the EGR system is activated, when the temperature of the coolant is equal to or higher than the predetermined temperature.