Ignition Coil Open Secondary Detection via IGBT Gate Voltage
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Solution Overview
Problem
Existing ignition systems face challenges in detecting an open secondary condition in the secondary coil of an ignition coil, leading to high energy handling requirements and costs for the switch, as monitoring voltage or current at such high levels necessitates large and costly components.
Innovation Solution
Monitoring the control signal at the control input of the switch, specifically the gate voltage of an IGBT, allows for detection of the open secondary condition with reduced complexity and cost, using a control signal received from the switch to inhibit ignition attempts and dissipate energy effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage or current is monitored at high levels to detect open secondary condition, then detection capability is improved, but component size and cost increase
Solution Approach 1:
The patent uses the control signal as an intermediary to indirectly detect the open secondary condition. Instead of directly monitoring high voltage or current at the secondary coil, the control signal from the switch is monitored to infer the secondary condition. This intermediary approach enables detection capability while avoiding the need for large, costly components designed to handle high voltage/current levels directly.
Solution Approach 2:
The patent replaces direct electrical monitoring (which would require robust, large components) with control signal analysis. By substituting the mechanical/electrical monitoring approach with a control-based detection method, the system achieves the same detection function with smaller, less costly components.
2Reliability
If switch is designed to handle high energy levels for open secondary conditions, then reliability is improved, but system cost and size increase
Solution Approach 1:
The patent implements preliminary detection of the open secondary condition by monitoring the control signal before excessive energy can damage the switch. By detecting the condition early through control signal analysis, the system can take preventive action (such as disabling the ignition coil) before high energy levels occur, thereby protecting the switch without requiring it to be oversized for such conditions.
Solution Approach 2:
The patent uses feedback from the control signal to monitor the health of the ignition system. The control signal provides information about the secondary condition, and this feedback is used to adjust system operation or trigger protective measures, ensuring switch reliability without requiring the switch to be designed for maximum stress conditions.
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 approach reduces the energy handling requirements of the switch, enabling the use of smaller and less costly components by detecting the open secondary condition and preventing excessive power dissipation, thereby minimizing system size and cost.
Implementation Method 1
an immediate change in current through a primary winding of the inductor can produce a high voltage. An ignition coil typically includes a primary coil and a secondary coil. Generally, the voltage on the secondary coil is proportionate to the voltage on the primary coil, amplified by a ratio of turns between the primary and secondary coils.
Implementation Method 2
the open secondary condition in the secondary coil of the ignition coil can be detected using a received gate voltage of the IGBT
Data Source
AI summary
This document discusses, among other things, a system and method for detecting an open secondary condition in a secondary coil of an ignition coil using a control signal received from a control input of a switch configured to control the flow of current to a primary coil of the ignition coil. In an example, the flow of current in the primary coil of the ignition coil can be controlled using an insulated gate bipolar junction transistor (IGBT), and the open secondary condition in the secondary coil of the ignition coil can be detected using a received gate voltage of the IGBT.