Pyro Igniter Circuit Self-Diagnostic Test Signal
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Solution Overview
Problem
Current pyro igniter circuits only check the internal integrity of the control circuit and not the complete circuit loop, leading to incomplete diagnostics and potential uncontrolled heat or fire in severe fault conditions.
Innovation Solution
A pyro igniter circuit with a shunt resistor, amplifier, pyro igniter disconnect element, coupling resistor, and supervisory circuit that transmits a test signal with a pulse duration and amplitude below the activation threshold, allowing for a thorough check of the entire circuit without activating the pyro igniter disconnect element, and includes current sensors to measure electric current for fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test signal is transmitted to check the pyro igniter circuit, then diagnostic capability is improved, but the risk of accidental activation increases
Solution Approach 1:
The test signal parameters (amplitude and pulse width) are specifically adjusted to remain below the activation threshold of the pyro igniter disconnect element. This allows the supervisory circuit to transmit a test signal that activates the amplifier and generates an ignition control signal for diagnostic purposes, while preventing the pyro igniter disconnect element from being triggered and cutting the power line.
2Reliability
If the complete circuit loop is checked, then reliability is improved, but device complexity increases
Solution Approach 1:
The supervisory circuit utilizes the existing operational components (amplifier, coupling resistor, shunt resistor) of the pyro igniter circuit to perform self-diagnostics. By transmitting a test signal that flows through these components and monitoring the resulting ignition control signal, the system checks the complete circuit loop using its own operational elements rather than requiring separate testing equipment or additional complex diagnostic infrastructure.
3Measurement precision
If a test signal with sufficient amplitude is transmitted, then fault detection accuracy is improved, but the pyro igniter disconnect element may be activated
Solution Approach 1:
The test signal amplitude is set to a partial level that is sufficient to activate the amplifier and generate an ignition control signal for diagnostic purposes, but deliberately kept below the threshold required to activate the pyro igniter disconnect element. This partial action enables fault detection in the amplifier and signal path without causing the protective disconnect function to trigger and interrupt the power line.
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 a complete and reliable check of the pyro igniter circuit without interfering with its functionality, preventing accidental activation and providing fast, analogue testing that can detect various faults, ensuring safe operation by preventing uncontrolled power line cuts.
Implementation Method 1
a shunt resistor (10) electrically connected in series with a power line (35)
Implementation Method 2
an amplifier (20) having first and second inputs respectively electrically connected to first and second terminals (11, 12) of the shunt resistor (10)
Implementation Method 3
a pyro igniter disconnect element (30) electrically connected to an output (24) of the amplifier (20) and configured to cut the power line (35)
Data Source
AI summary
A pyro igniter circuit and a method for testing the same is provided. The pyro igniter circuit includes a supervisory circuit configured to: transmit a test signal having a pulse duration time below an igniter activation pulse time of a pyro igniter disconnect element and/or an ignition control signal, in response to the transmitted test signal, has an amplitude below an igniter activation amplitude of the pyro igniter disconnect element; and receive a diagnostic response signal in response to the transmitted test signal.