Engine Cooling System with Dual Bypass Flow Control
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Solution Overview
Problem
Existing engine cooling systems face challenges in precisely controlling the temperature of the combustion chamber, particularly for advanced combustion control like CI combustion, due to limitations in coolant flow control and heat transfer efficiency, leading to unstable cooling responses and fuel efficiency issues.
Innovation Solution
A cooling system with a water jacket in the cylinder head, incorporating a heat exchanger, first and second bypass passages, and a thermally-actuated valve, along with a flow control device that adjusts coolant flow between these passages to optimize heat transfer coefficients and coolant temperatures, ensuring stable and high-response cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant flows through a long bypass passage with heat exchange apparatuses, then heat exchange capability is improved, but flow rate is reduced and response becomes slow
Solution Approach 1:
The bypass passage is divided into two separate passages: a first bypass passage with heat exchange apparatuses for temperature control, and a second bypass passage without apparatuses for high-speed flow. This segmentation allows each passage to optimize its function independently, resolving the contradiction between heat exchange capability and flow rate.
Solution Approach 2:
A flow control valve is introduced as an intermediary device to regulate and distribute coolant flow between the two bypass passages. This valve enables dynamic adjustment of flow distribution, allowing the system to achieve both temperature control and high response by directing flow appropriately between the two passages.
2Measurement precision
If coolant flow amount to water jacket is kept constant, then system simplicity is maintained, but temperature control precision deteriorates
Solution Approach 1:
The system transitions from constant flow to dynamic flow control by introducing a flow control valve that can adjust the distribution of coolant between the two bypass passages. This dynamic adjustment capability enables precise temperature control while maintaining reasonable system complexity through a single valve mechanism.
3Temperature
If coolant temperature is kept low to suppress combustion chamber temperature increase, then cooling effectiveness is improved, but combustion control precision deteriorates
Solution Approach 1:
The system changes the temperature parameter of coolant by providing two different bypass passages: one that cools the coolant through heat exchange apparatuses, and another that maintains higher temperature. The flow control valve dynamically adjusts the mixture ratio of cool and warm coolant to achieve the desired combustion chamber wall temperature for precise combustion 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 configuration allows for precise control of the combustion chamber wall temperature, enabling advanced combustion control and improved fuel efficiency by adjusting coolant flow and temperature to match engine load conditions.
Implementation Method 1
a heat exchanger that cools the coolant
Implementation Method 2
a thermally-actuated valve that opens or closes according to a temperature
Data Source
AI summary
An engine cooling system is provided, which includes a water jacket through which coolant flows, a heat exchanger that cools the coolant, a first bypass passage that bypasses the heat exchanger and recirculates the coolant to the water jacket, a radiator passage that recirculates the coolant to the water jacket via the heat exchanger, and a flow control device that is installed at a location where a coolant passage branches into the first bypass passage and the radiator passage and performs a water flow control to adjust a coolant amount flowing into the water jacket by adjusting a coolant amount flowing through the first bypass passage. A thermally-actuated valve connected with the radiator passage via a second bypass passage is provided to the first bypass passage, and when this valve opens, the coolant flowing through the first bypass passage flows into the radiator passage through the second bypass passage.