Adaptive EGR Cooling System for Diesel Engine Condensation Control
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Solution Overview
Problem
Existing diesel engine EGR systems face challenges in effectively controlling condensation of exhaust gas constituents, which can impact NOx generation and engine performance, particularly due to the cooling of recirculated exhaust gas.
Innovation Solution
A cooling system with multiple loops and valves that selectively apportion coolant flow to manage heat transfer and condensation, including a first and second heat exchanger, radiators, and a charge air cooler, allowing for controlled coolant distribution to both the EGR system and charge air cooler, optimizing coolant flow to mitigate condensation and enhance engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas is cooled through heat exchangers to reduce NOx generation, then emission control is improved, but condensation of exhaust gas constituents occurs which harms engine performance
Solution Approach 1:
The system dynamically adjusts coolant flow distribution to the first and second heat exchangers based on operating conditions. The control system monitors exhaust gas temperature and condensation risk, then modulates coolant flow rates to maintain optimal cooling without causing condensation, allowing the system to adapt between emission control mode and condensation prevention mode
Solution Approach 2:
The system changes physical parameters including coolant flow rate, coolant temperature, and heat exchanger cooling intensity. By adjusting these parameters dynamically, the system can reduce cooling intensity when condensation risk is high while maintaining sufficient cooling for NOx control when conditions permit
2Object-generated harmful factors
If coolant flow is increased to heat exchangers to improve exhaust gas cooling, then NOx emission control is enhanced, but charge air cooling capability is reduced due to coolant apportionment
Solution Approach 1:
The control system dynamically apportions coolant flow between the EGR heat exchangers and charge air cooler based on real-time engine operating conditions. When NOx control is prioritized, more coolant is directed to heat exchangers; when charge air cooling is needed, flow is redirected accordingly, creating a dynamic balance between competing thermal management requirements
Solution Approach 2:
The coolant circulation system serves multiple functions simultaneously through a unified control architecture. The same coolant loop provides cooling for both the EGR system and charge air, with intelligent flow distribution that allows the system to fulfill multiple thermal management functions based on priority needs
3Device complexity
If a single coolant loop is used for both EGR cooling and charge air cooling, then system complexity is reduced, but control precision over condensation and temperature management is insufficient
Solution Approach 1:
The coolant circulation system is segmented into multiple controllable loops or flow paths with independent control valves. This segmentation allows precise control of coolant flow to each heat exchanger and charge air cooler independently, enabling fine-tuned thermal management while maintaining a relatively simple overall system architecture
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 effectively manages exhaust gas cooling and charge air temperature, reducing NOx formation and improving engine efficiency by controlling condensation and optimizing coolant distribution, thereby enhancing engine performance and emission control.
Implementation Method 1
a first heat exchanger and a second heat exchanger to the intake system
Implementation Method 2
coolant circulation means for circulating liquid coolant in multiple loops and comprising first and second radiators
Implementation Method 3
a first heat exchanger and a second heat exchanger to the intake system
Implementation Method 4
Control of condensation may be a factor in the design of various engine systems
Implementation Method 5
a charge air cooler for cooling conveyed air
Implementation Method 6
the first radiator where heat in coolant that has passed through the coolant passageways is rejected
Data Source
AI summary
A first loop contains engine coolant passageways (28, 30) and a first radiator (34). A second loop contains a first EGR cooler (48). A third loop contains a second EGR cooler (50), a second radiator (36), a charge air cooler (26LP), a first valve (66), and a second valve (64). Valve (64) apportions coolant flow entering an inlet (64A) to parallel flow paths, one including second radiator (36) and the other being a bypass around radiator (36). The apportioned flows merge into confluent flow to both an inlet of charge air cooler (26LP) and a first inlet (66B) of valve (66). Valve (66) has an outlet (66C) communicated to an inlet of second EGR cooler (50). The first condition of valve (66) closes a second inlet (66A) to coolant flowing toward both the second inlet (66A) and inlet (64A) while opening inlet (66B) to outlet (66C). The second condition of valve (66) opens second inlet (66A) to coolant flowing toward second inlet (66A) and inlet (64A) of the valve (64) while closing first inlet (66B) of valve (66) to outlet (66C) of valve (66).