Ignition Device Overvoltage Protection Synchronization
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Solution Overview
Problem
Existing ignition devices for internal combustion engines face issues with overvoltage protection triggering at unexpected times, leading to premature ignition and potential engine damage due to the overvoltage protection circuit activating outside of intended ignition periods.
Innovation Solution
An ignition device with an overvoltage protection circuit that monitors voltage levels and synchronizes its inhibit signal output with the energization control signal duration, ensuring the switching device is protected from overvoltage only when necessary and preventing adverse ignition timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the overvoltage protection circuit is activated to protect the switching device from overvoltage damage, then the switching device is protected from thermal damage, but the ignition timing becomes incorrect causing premature ignition
Solution Approach 1:
The overvoltage protection circuit dynamically adjusts its protection behavior based on the state of the switching device. When the switching device is in the off state, the protection circuit activates to prevent overvoltage damage. When the switching device is in the on state during normal ignition operation, the protection circuit suspends its operation to avoid interfering with ignition timing. This dynamic adaptation resolves the contradiction between protection and timing precision.
Solution Approach 2:
The protection circuit monitors the voltage level as a parameter and changes its operational state based on voltage thresholds. When voltage exceeds the threshold during switching device off-state, protection is activated. When voltage is within normal range during switching device on-state, normal ignition operation proceeds. This parameter-based control allows the system to maintain both protection capability and ignition timing precision under different operating conditions.
2Reliability
If the overvoltage protection circuit turns off the switching device when voltage exceeds threshold, then the switching device is protected from overcurrent, but the high voltage generation is interrupted causing unexpected premature ignition
Solution Approach 1:
The protection circuit dynamically responds to voltage conditions in conjunction with the switching device state. During normal ignition operation when the switching device is on, if voltage exceeds the threshold, the protection circuit does not immediately turn off the switching device, allowing the ignition operation to complete stably. The protection is applied selectively based on the operational phase, maintaining both device protection and ignition stability.
3Reliability
If the overvoltage protection circuit operates continuously to protect the switching device, then the switching device is protected from damage, but the ignition signal response is delayed affecting ignition timing
Solution Approach 1:
The protection circuit operates dynamically rather than continuously. It monitors voltage conditions and activates protection only when necessary (when voltage exceeds threshold during switching device off-state). During normal ignition operation, the protection circuit remains inactive, allowing the ignition signal to be responded to immediately without delay. This dynamic operation maintains both protection and fast response speed.
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 effectively prevents overvoltage damage to the switching device and ensures correct ignition timing, reducing the risk of engine damage from premature ignition.
Implementation Method 1
an ignition coil which includes a primary winding and a secondary winding and in which an electrical current flowing through the primary winding is changed to develop a high voltage at the secondary winding
Data Source
AI summary
An ignition device for an internal combustion engine includes a switching circuit and a control circuit. The control circuit monitors a voltage level inputted to a switching device which is installed in the switching circuit and connected to a primary winding of an ignition coil. The control circuit includes an overvoltage protection circuit which outputs an energization inhibit signal to inhibit energization of the switching device when the monitored voltage level is higher than an overvoltage threshold level. When the monitored voltage level exceeds the overvoltage threshold level in an output duration in which the energization control signal is outputted, the overvoltage protection circuit stops output of the energization inhibit signal until the output duration expires. This enables the switching device to be protected from damage and an ignition operation to be executed at a correct timing to eliminate a risk of damage to the internal combustion engine.