Ignition Device Overvoltage Protection via Voltage Detection
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Solution Overview
Problem
Conventional ignition devices for internal combustion engines that use a battery as the destination for the return flow of current from the primary coil do not adequately protect other devices from overvoltage during a load dump state, where the connection between the return circuit and the battery is broken.
Innovation Solution
The ignition device incorporates a first circuit for starting spark discharge, a second circuit for maintaining spark discharge, a return circuit for directing current back to the battery, a voltage detection unit to monitor battery voltage, and an operation stopping unit that halts energy supply when excessive voltage is detected, thereby preventing overvoltage to other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the second circuit continues to supply energy to the primary coil during a load dump state, then the spark discharge can be maintained, but overvoltage is applied to other devices connected to the return circuit
Solution Approach 1:
The voltage detection unit continuously monitors the voltage on the battery side of the primary coil and provides feedback to the control unit. When the voltage exceeds a predetermined threshold (indicating a load dump state), the control unit stops the second circuit from supplying energy to the primary coil, thus preventing overvoltage damage to other devices while maintaining spark discharge under normal conditions
Solution Approach 2:
The voltage detection unit acts as an intermediary between the electrical system and the control unit. It detects abnormal voltage conditions and transmits this information to the control unit, which then adjusts the operation of the second circuit accordingly, preventing direct harm to other devices
2Adaptability or versatility
If a return circuit is provided to allow current to flow back to the battery, then the second circuit can continue energizing the primary coil, but the system becomes vulnerable to overvoltage during load dump states
Solution Approach 1:
The voltage detection unit is positioned to detect voltage abnormalities before they can cause damage to other devices. The system proactively identifies load dump states by monitoring voltage levels and preemptively stops the second circuit operation, preventing overvoltage damage before it occurs
Solution Approach 2:
The control unit receives continuous feedback from the voltage detection unit about the electrical system's state. Based on this feedback, the control unit dynamically adjusts the operation of the second circuit, stopping energy supply when voltage exceeds safe levels while allowing flexible operation under normal 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 configuration effectively stops the energy supply during a load dump state, protecting other devices from overvoltage and ensuring safe operation of the ignition system.
Implementation Method 1
The energization of the primary coil is turned on/off to cause electromagnetic induction to supply energy to the ignition plug, and thereby spark discharge is generated
Data Source
AI summary
The return circuit of the ignition device returns to the battery the current supplied to the primary coil by the operation of the second circuit, and the voltage detection unit detects the voltage VB. The operation stopping unit monitors the voltage VB and when it is determined that the voltage VB is excessive, that is, when the voltage VB exceeds the threshold voltage VBc, it stops the supply of energy by the second circuit. As a result, when a load dump state occurs, the supply of energy by the second circuit can be stopped. Thus, when a load dump state occurs by the operation of the second circuit, other devices can be protected from overvoltage.