Thermostat Preheating Control for Engine Cooling Response
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Solution Overview
Problem
Existing internal combustion engine cooling systems face delays in thermostat opening response due to the time required for wax volume change, leading to abnormal temperature rises and potential engine performance and durability issues, especially during abrupt thermal load changes.
Innovation Solution
An internal combustion engine cooling system with a control device that determines the timing of heater power supply based on engine rotation speed, load, and cooling fluid temperature, using pre-power and standby power strategies to preheat the thermostat and improve opening response, thereby preventing abnormal temperature rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the thermostat relies on natural wax volume change with temperature, then the structure remains simple, but the opening response is delayed causing abnormal temperature rise
Solution Approach 1:
The heater core receives cooling water in advance before the thermostat needs to open, preheating the cooling water so that when the thermostat opens, the engine receives pre-heated cooling water immediately, eliminating the temperature delay without requiring a faster-acting thermostat mechanism
Solution Approach 2:
A temperature sensor is introduced as an intermediary between the cooling water temperature and the control system. The sensor detects temperature changes and triggers the heater core to supply hot water, creating a feedback-controlled system that compensates for the slow thermostat response
2Reliability
If the thermostat opens only when cooling water temperature rises, then the control logic is simple, but the response is delayed during abrupt thermal load changes
Solution Approach 1:
The system performs preliminary heating by routing cooling water through the heater core before the thermostat opens, ensuring the cooling water is already heated when needed, thus preventing temperature drops during abrupt load changes
Solution Approach 2:
A temperature sensor provides continuous feedback on cooling water temperature, allowing the control system to detect temperature trends and activate the heater core proactively before the thermostat needs to open, compensating for the time delay
3Temperature
If no pre-heating control is applied, then the control system is simple, but abnormal temperature rise occurs during warm-up
Solution Approach 1:
The temperature sensor provides feedback on cooling water temperature, enabling the control unit to monitor temperature conditions and adjust heater core operation accordingly, maintaining stable temperature without excessive complexity
Solution Approach 2:
The system changes the temperature parameter of the cooling water by routing it through the heater core, transforming cold cooling water into hot cooling water to prevent abnormal temperature rise during engine warm-up
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
The system effectively heats the thermostat to prevent abnormal cooling fluid temperature rises and enhance engine cooling performance by optimizing the thermostat's opening response and duty control strategies.
Implementation Method 1
an electronically-controlled thermostat including a heater is used as a valve for switching a flow path of cooling water
Implementation Method 2
The thermostat is a wax thermostat which opens and closes by utilizing a volume change of wax which occurs with a temperature change
Implementation Method 3
a radiator for cooling the cooling fluid
Implementation Method 4
a radiator for cooling the cooling fluid
Data Source
AI summary
An internal combustion engine cooling system, including: an internal combustion engine; a cooling circuit in which cooling fluid for cooling the internal combustion engine is circulated; a radiator for cooling the cooling fluid; a radiator circuit that branches from the cooling circuit to guide the cooling fluid to the radiator and return the cooling fluid having passed the radiator to the cooling circuit; a thermostat that is provided in a portion where the cooling circuit and the radiator circuit are connected to each other and that opens and closes a path between cooling circuit and the radiator circuit; a heater for heating the thermostat; and a control device for controlling the heater.