Cooling Fan Controller Signal Segmentation for Abnormality Detection
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Solution Overview
Problem
The existing cooling fan controller systems cannot distinguish between a stopped cooling fan and an abnormality in the cooling system, leading to complex determination processes for the host ECU, as it supplies a low-level signal for both conditions.
Innovation Solution
The cooling fan controller uses distinct pulse signals or duty ratios on separate signal lines to differentiate between the fan's operational state and abnormality detection, allowing the host ECU to determine abnormalities based on the signal from one line only.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the cooling fan controller supplies a low-level signal to indicate the fan is stopped, then the rotational speed information is accurately represented, but the host ECU cannot distinguish between a stopped fan and an abnormality in the cooling system
Solution Approach 1:
The patent divides the diagnostic function into two separate signal lines: one for rotational speed information and another for abnormality status. This segmentation allows the host ECU to receive distinct signals for fan operation status and abnormality detection, eliminating the ambiguity of using a single signal line for both purposes.
Solution Approach 2:
The patent introduces an intermediary signal line that carries abnormality status information from the cooling fan controller to the host ECU. This intermediary channel enables the host ECU to differentiate between normal stoppage and abnormal conditions without interfering with the rotational speed signal transmission.
2Reliability
If the host ECU determines abnormalities by checking signal levels on both signal lines, then abnormality detection is possible, but the determination process becomes complicated
Solution Approach 1:
By separating abnormality status information onto its own signal line, the patent simplifies the host ECU's determination process. The ECU can independently evaluate the abnormality signal without needing to analyze combinations of signal levels across multiple lines, reducing computational complexity while maintaining detection reliability.
3Device complexity
If the cooling fan controller uses the same signal line for both rotation command and rotational speed feedback, then the communication interface is simplified, but the host ECU cannot easily determine system abnormalities
Solution Approach 1:
The patent segments the communication function by dedicating specific signal lines to specific purposes: one line for rotational speed feedback and another for abnormality status. This segmentation preserves the simplicity of the communication interface while enabling comprehensive diagnostic information transmission.
Solution Approach 2:
The patent enhances the functionality of the cooling fan controller by enabling it to transmit multiple types of information (rotational speed and abnormality status) through the communication interface. This multi-functionality is achieved while maintaining a simple hardware configuration through proper signal line assignment.
Data Source
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AI summary
Provided is a cooling fan controller connected to a host controller via a first signal line and a second signal line and configured to control rotation of a cooling fan on the basis of a rotation command output from the controller via the first signal line, the cooling fan controller including: an abnormality detector configured to detect an abnormality of a monitoring target in a mechanism configured to control the cooling fan; and an output part configured to output a first signal according to rotation of the cooling fan to the second signal line when the abnormality is not detected by the abnormality detector and configured to output a second signal different from the first signal to the second signal line when the abnormality is detected by the abnormality detector.