External Heater Operation Determination Using Refrigerant Temperature
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Solution Overview
Problem
Existing systems face challenges in accurately determining whether an external heater, such as a block heater attached to an engine, is operating, especially in vehicles like hybrid electric vehicles where engine cooling water circulation is not initiated during the Ready-ON state, leading to difficulties in temperature distribution and sensor malfunction detection.
Innovation Solution
An external heater operation determination system that includes a first device to be heated by the external heater, a second device to be cooled by a refrigerant, a circulation device for the refrigerant, and a temperature detection device. The system determines the external heater's operation based on changes in refrigerant temperature after circulation begins, and also includes a malfunction determination device for temperature sensors, adjusting thresholds depending on the external heater's status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If engine cooling water circulation is not initiated during Ready-ON state, then energy consumption is reduced, but temperature distribution becomes unclear and external heater operation cannot be determined
Solution Approach 1:
The patent introduces refrigerant as an intermediary substance to detect engine temperature. The refrigerant circulates through the engine and absorbs heat, allowing temperature detection without requiring engine cooling water circulation. The temperature detection device measures refrigerant temperature to determine external heater operation status, solving the measurement precision problem while maintaining energy savings.
Solution Approach 2:
The patent replaces the traditional engine cooling water circulation system with a refrigerant circulation system for temperature detection purposes. Instead of relying on the mechanical cooling water pump and radiator system, the invention uses the refrigerant circulation system (originally for air conditioning) to achieve temperature measurement, eliminating the need to initiate engine cooling water circulation during Ready-ON state.
2Measurement precision
If temperature detection device is placed to detect refrigerant temperature, then external heater operation can be determined, but false determination may occur if refrigerant is not circulating
Solution Approach 1:
The patent implements a feedback mechanism where the determination device continuously monitors refrigerant temperature changes and compares them against expected patterns. When refrigerant circulation is detected, the system evaluates temperature rise patterns to determine external heater operation. The system adjusts its determination logic based on circulation status, preventing false determinations when refrigerant is not circulating.
Solution Approach 2:
The patent makes the determination logic dynamic by adjusting the detection criteria based on refrigerant circulation status. When refrigerant is circulating, the system uses temperature change rate and absolute temperature values to determine external heater operation. When circulation is absent, the system recognizes this state and adjusts its determination approach, preventing false positives while maintaining detection capability when circulation occurs.
3Reliability
If multiple temperature sensors are used for malfunction detection, then sensor reliability improves, but determination threshold must be adjusted when external heater is operating
Solution Approach 1:
The patent dynamically changes the determination threshold parameter based on external heater operation status. When the external heater is determined to be operating, the system switches to a first determination threshold that accounts for the additional heat source. When the external heater is not operating, the system uses a second determination threshold. This parameter adaptation allows accurate malfunction detection across different operating conditions without requiring complex sensor arrays.
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
Enables accurate and timely determination of the external heater's operation, preventing false determinations and ensuring proper vehicle control, even in vehicles where engine cooling water circulation is not initiated, and allows for precise malfunction detection in temperature sensors.
Implementation Method 1
a second device, separate from the first device, to be cooled by a refrigerant
Implementation Method 2
a circulation device configured to circulate the refrigerant through a circuit
Implementation Method 3
a temperature detection device configured to detect a temperature of the refrigerant
Implementation Method 4
a first device to be heated by an attached external heater
Data Source
AI summary
An external heater operation determination system includes, in a vehicle: a first device to be heated by an attached external heater; a second device, separate from the first device, to be cooled by a refrigerant; a circulation device configured to circulate the refrigerant through a circuit; and a temperature detection device that is configured to detect a temperature of the refrigerant and disposed such that if the refrigerant is not circulating through the circuit, the temperature of the refrigerant detected by the temperature detection device in the circuit does not rise even if the external heater is operating, whereas if the refrigerant is circulating through the circuit, the detected temperature of the refrigerant changes. The external heater operation determination system includes a determination device able to determine that the external heater is not operating on a basis of a change in the temperature after the circulation of the refrigerant.