Engine Cooling System Flow Control for Combustion Chamber Temperature
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Solution Overview
Problem
Existing engine cooling systems struggle to adjust the wall temperature of the combustion chamber with high response to changes in engine load due to the large calorific capacity of the coolant, making it difficult to maintain optimal temperatures for efficient combustion.
Innovation Solution
An engine system with a circulation system that adjusts the flow rate of coolant through a water jacket using a flow rate control device and a thermally-actuated valve, allowing coolant to bypass or flow through a radiator passage based on engine load, thereby changing the heat transfer coefficient and maintaining suitable wall temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the flow rate of coolant is increased to cool the combustion chamber, then the wall temperature of the combustion chamber decreases, but the response time to engine load changes is slow due to the large calorific capacity of the coolant
Solution Approach 1:
The cooling system is segmented into multiple independent passages: a first passage that bypasses the radiator and a second passage that goes through the radiator. This segmentation allows independent control of coolant flow rates in each passage, enabling rapid adjustment of total coolant flow rate through the water jacket without being constrained by the thermal mass of the coolant itself.
Solution Approach 2:
The system dynamically adjusts the opening degrees of flow control valves in real-time based on engine load conditions. The first flow control valve controls the bypass passage and the second flow control valve controls the radiator passage, allowing continuous dynamic adjustment of coolant flow distribution to match varying thermal demands of the combustion chamber.
2Temperature
If the temperature of coolant is adjusted to control combustion chamber temperature, then the wall temperature changes, but it takes a long period of time due to the large calorific capacity of the coolant
Solution Approach 1:
By dividing the cooling circuit into separate bypass and radiator passages with independent flow control, the system can rapidly change the proportion of coolant flowing through each path. This allows quick adjustment of heat exchange quantity without waiting for the entire coolant mass to reach a new temperature equilibrium.
Solution Approach 2:
The system changes the flow rate parameter of coolant through the water jacket by adjusting valve opening degrees, rather than waiting for the temperature parameter of the coolant to change. This parameter substitution enables rapid response because flow rate can be adjusted instantaneously while temperature changes require time due to coolant's thermal mass.
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 allows for rapid adjustment of coolant flow rates to match engine load changes, maintaining optimal combustion chamber temperatures and improving thermal efficiency and stability across varying engine loads.
Implementation Method 1
a thermally-actuated valve that is connected to the radiator passage and opens to allow the coolant to pass through the heat exchanger
Implementation Method 2
a radiator passage including a heat exchanger
Implementation Method 3
a circulation system that is attached to the engine and circulates coolant through the water jacket
Implementation Method 4
a flow rate control device that adjusts a flow rate of coolant flowing through the water jacket by adjusting a flow rate of coolant flowing through each of the radiator passage and the bypass passage
Data Source
AI summary
An engine system is provided, including an engine having a water jacket, a circulation system that circulates coolant through the water jacket, and a controller. The circulation system includes a radiator passage including a heat exchanger, a bypass passage bypassing the heat exchanger, a flow rate control device, and a thermally-actuated valve connected to the radiator passage and that opens to allow the coolant to pass through the heat exchanger. When an engine load is below a first load, the controller controls the flow rate control device to adjust the coolant flow rate flowing through the water jacket according to the load, by closing the radiator passage and adjusting the coolant flow rate flowing through the bypass passage. When the load is above the first load, the controller controls the flow rate control device so that the coolant flows through each of the radiator passage and the bypass passage.