Automotive Alternator Disconnection Detection via Voltage Response Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control apparatuses for automotive alternators face challenges in reliably detecting disconnection between the alternator and the on-board battery, often due to increased complexity and cost from multiple voltage detections, or difficulty in distinguishing disconnection when the battery is fully charged, and limitations in applying these systems to cases where the alarm lamp is powered from sources other than the battery.
Innovation Solution
A control apparatus that includes a switch, a target voltage setter, a voltage regulator, and a disconnection detector, which intermittently excites the alternator and detects disconnection based on the time required to change the output voltage from a lower to a higher value, or the difference in duty cycle of the switch, allowing for reliable detection without the need for multiple voltage detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both output voltage of alternator and terminal voltage of battery are detected to identify disconnection, then disconnection detection capability is improved, but number of terminals and leads increases making system complex and expensive
Solution Approach 1:
The invention extracts only the essential voltage detection point (alternator output terminal B) from the dual-voltage detection system, eliminating the need to detect battery terminal voltage separately. This reduces the number of terminals and leads while maintaining disconnection detection capability through intelligent analysis of alternator output characteristics.
Solution Approach 2:
The voltage detection system serves multiple functions: it detects disconnection between alternator and battery, monitors alternator output status, and provides control signals for the field transistor. This multi-functionality eliminates the need for separate detection circuits, reducing overall system complexity.
2Device complexity
If only output voltage of alternator is detected to simplify the system, then device complexity is reduced, but reliable disconnection detection becomes difficult when battery is fully charged
Solution Approach 1:
The invention dynamically analyzes the relationship between field transistor control signals and alternator output voltage characteristics. By monitoring how the output voltage responds to field transistor switching under different operating conditions (charged vs. uncharged battery), the system reliably detects disconnection using only alternator output voltage detection.
Solution Approach 2:
The system changes the operating parameters of the alternator by controlling the field transistor switching and monitors the resulting output voltage characteristics. This allows differentiation between disconnection conditions and normal full-charge conditions by analyzing voltage response patterns rather than relying on static voltage thresholds.
3Ease of operation
If voltage difference threshold method is used to detect disconnection, then detection simplicity is improved, but detection reliability decreases when battery is fully charged due to small voltage difference
Solution Approach 1:
The invention uses feedback from the field transistor control system to interpret alternator output voltage characteristics. By analyzing the relationship between control signals and output voltage response, the system reliably detects disconnection even when voltage differences are small, overcoming the limitations of simple threshold-based methods.
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 enables reliable detection of disconnection between the alternator and the battery, overcoming the limitations of prior art by simplifying the system and improving detection accuracy, while maintaining system efficiency and reducing costs.
Implementation Method 1
an automotive alternator 2 which is rotated by an engine (not shown) to generate electrical energy
Implementation Method 2
a voltage regulator 33 for regulating an output voltage of the alternator 2
Data Source
AI summary
According to the present invention, there is provided a control apparatus for an automotive alternator which includes a switch, a target voltage setter, a voltage regulator, and a disconnection detector. The switch is configured to be selectively turned on and off so as to intermittently excite the alternator. The target voltage setter works to set a target voltage. The voltage regulator works to regulate an output voltage of the alternator to the target voltage through controlling on/off operation the switch. The disconnection detector works to detect disconnection between the alternator and an on-board battery to be charged by the alternator. The disconnection detector is configured to detect the disconnection, when the target voltage is changed from a lower value to a higher value, based on a time required for the voltage regulator to bring the output voltage of the alternator from the lower value to the higher value.