Diode Rectification Circuit for Igniter and Relay Fault Detection
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Solution Overview
Problem
Existing methods for determining faults in gas powered appliances, such as hot surface igniters and relays, are inaccurate and difficult to diagnose due to signal overlap from line voltage changes and grounding voltage interference, leading to false fault detection and unnecessary appliance operation.
Innovation Solution
The use of diode rectification in a circuit assembly to analyze signal waveforms at the control input, allowing for accurate detection of igniter, inducer relay, and igniter relay faults by distinguishing between ON and OFF states and measuring grounding voltage without separate hardware, thereby eliminating the need to start the heat cycle for fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional fault detection methods are used without diode rectification, then the appliance can operate, but fault detection accuracy deteriorates due to signal overlap from line voltage changes and grounding voltage interference
Solution Approach 1:
A diode rectification circuit is introduced as an intermediary component between the control input and the fault detection logic. The diode circuit rectifies the AC signal to produce a DC voltage that is proportional to the RMS value of the input signal, thereby eliminating the harmful effects of line voltage changes and grounding voltage interference on fault detection accuracy.
Solution Approach 2:
The patent replaces traditional analog signal comparison methods with a diode-based rectification system. Instead of directly comparing AC signals that are susceptible to interference, the system converts AC signals to DC voltages through diode rectification, enabling more reliable fault detection by substituting the measurement approach rather than the physical components being measured.
2Adaptability or versatility
If separate hardware is used for grounding voltage measurement, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The diode rectification circuit serves multiple functions simultaneously: it enables fault detection for relays and igniters while also providing grounding voltage measurement capability. By using the same circuit infrastructure for both purposes, the patent achieves multi-functionality without increasing device complexity, as the diode circuit naturally produces a voltage proportional to the input signal regardless of the specific measurement need.
3Difficulty of detecting and measuring
If heat cycle is started for fault detection, then fault detection opportunity is improved, but energy consumption and operational time increase
Solution Approach 1:
The patent enables fault detection to occur during the pre-purge phase, which is before the heat cycle would normally begin. By implementing fault detection using the diode rectification circuit during this preliminary phase, the system can identify faults and prevent unnecessary heat cycle initiation, thereby reducing operational time and energy consumption while maintaining comprehensive fault detection capability.
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 solution provides reliable and accurate fault detection, eliminating false positives and allowing for precise identification of faults without interfering with line voltage fluctuations or grounding voltage, reducing repair time and costs by enabling technicians to diagnose issues correctly.
Implementation Method 1
the circuit assembly includes a diode rectification circuit configured to rectify an alternating current (AC) signal received at the control input
Implementation Method 2
a hot surface igniter that heats up based on a supplied current to ignite a combustible gas
Data Source
AI summary
Exemplary embodiments are disclosed of controls including circuit assemblies configured for determining igniter, inducer relay, and igniter relay faults. In exemplary embodiments, a control for a system includes an input configured to receive a control signal, an inducer relay, an igniter relay, and a circuit assembly. The circuit assembly is configured to be coupled to the inducer relay, the igniter relay, and an igniter of the system. The circuit assembly comprises a plurality of diodes and is configured to enable detection of and distinguishing between a failure of the igniter, a failure of the inducer relay, and a failure of the igniter relay as determined by a waveform of the control signal at the input of the control for a given one of a plurality of operational states of the control.