Engine Cooling System with Dual Loops and Mixing Valve
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Solution Overview
Problem
Existing engine systems with EGR systems face limitations in stably cooling recirculating exhaust gases due to temperature differences between engine coolant and exhaust gas, which can lead to insufficient NOx reduction and potential damage to the EGR cooler.
Innovation Solution
An engine system with two cooling loops, including a first coolant loop for the engine and a second coolant loop for a water-cooled intercooler, where the coolants are mixed and controlled by a temperature adjusting valve to maintain stable temperatures for the EGR cooler, preventing excessive cooling and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If engine coolant is used to cool recirculating exhaust gas, then the EGR system can be implemented, but the cooling is insufficient due to high engine coolant temperature (about 90°C)
Solution Approach 1:
The cooling system is divided into two separate loops: a first coolant loop for the engine and a second coolant loop for the water-cooled intercooler. This segmentation allows each loop to operate at its optimal temperature independently, enabling stable cooling of exhaust gas without compromising engine cooling performance.
Solution Approach 2:
A temperature adjusting valve is introduced as an intermediary device to control the mixing ratio between hot engine coolant and cold intercooler coolant. This mediator enables precise temperature control of the mixture coolant, ensuring stable cooling of exhaust gas while protecting the EGR cooler from excessive cooling.
2Temperature
If low temperature coolant (about 45°C) is used to cool exhaust gas, then cooling effectiveness is improved, but the EGR cooler may be excessively cooled and damaged
Solution Approach 1:
The temperature adjusting valve dynamically controls the mixing ratio between hot and cold coolants based on operating conditions. This dynamic adjustment ensures that the EGR cooler receives coolant at an appropriate temperature that provides effective cooling without causing excessive cooling damage, adapting to varying engine loads and ambient conditions.
Solution Approach 2:
The system changes the temperature parameter of the coolant by mixing hot engine coolant with cold intercooler coolant in controlled proportions. This parameter adjustment allows the EGR cooler to operate within its optimal temperature range, preventing both insufficient cooling and excessive cooling damage.
3Reliability
If a two cooling loop system with coolant mixing is implemented, then stable cooling and EGR cooler protection are achieved, but the system complexity increases
Solution Approach 1:
The temperature adjusting valve serves multiple functions: it controls the mixing ratio of coolants, regulates the temperature of mixture coolant, and protects the EGR cooler from excessive cooling. This multi-functionality reduces the need for additional separate control systems, thereby limiting the increase in overall system complexity while achieving reliable temperature control.
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 solution allows for stable cooling of recirculating exhaust gases, effectively reducing NOx generation while preventing damage to the EGR cooler by appropriately mixing and controlling the coolant temperatures.
Implementation Method 1
a first coolant loop in which a first coolant circulates through an engine and a first radiator, a second coolant loop in which a second coolant circulates through a water-cooled intercooler and a second radiator
Implementation Method 2
a first coolant pump disposed to pump the first coolant, a second coolant pump pumping the second coolant may be disposed in the second coolant loop
Data Source
AI summary
An engine system having two cooling loops may include a first coolant loop in which a first coolant circulates through an engine and a first radiator, a second coolant loop in which a second coolant circulates through a water-cooled intercooler and a second radiator, a first branch line that branches from one side of the first coolant loop, a second branch line that branches from one side of the second coolant loop, a mixture line allowing the first coolant and the second coolant to be mixed to flow therein, and branching to the first coolant loop and the second coolant loop, a temperature adjusting valve configured to control a temperature of the mixture coolant flowing in the mixture line, and a mixture coolant line allowing the mixture coolant to flow, and branching to the first coolant loop and the second coolant loop.