Ignition Coil Recirculation Timing for Voltage Stress Protection
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Solution Overview
Problem
Conventional ignition devices for internal combustion engines face issues with excessive voltage stress on the energy supply circuit due to high voltages occurring in the primary coil during missing or short spark discharges, which can lead to potential damage and inefficiencies.
Innovation Solution
The proposed ignition device incorporates a recirculation circuit and controller that permits and controls current recirculation through a specific path, using an interruption signal to initiate recirculation before excessive voltage stress is applied, and sets an end time for recirculation to prevent interference with subsequent current supply, thereby protecting the energy supply circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main ignition circuit interrupts current through the primary coil to cause spark discharge, then ignition function is achieved, but excessive voltage stress is applied to the energy supply circuit
Solution Approach 1:
A recirculation circuit is introduced as an intermediary component with a recirculation switch that provides an alternative current path. When the recirculation switch is turned on, it mediates between the primary coil and the energy supply circuit, allowing current to recirculate through the recirculation path instead of forcing it through the energy supply circuit, thereby protecting the energy supply circuit from excessive voltage stress while maintaining ignition functionality.
Solution Approach 2:
The recirculation switch is turned on in advance before the main ignition circuit interrupts the current. This preliminary action prepares the recirculation path ahead of time, ensuring that when the interruption occurs and voltage spikes are generated, the recirculation circuit is already in place to handle the voltage stress, preventing damage to the energy supply circuit.
2Object-affected harmful factors
If current recirculation is permitted continuously, then voltage stress is prevented, but interference with subsequent current supply occurs
Solution Approach 1:
The recirculation switch operates periodically rather than continuously. It is turned on temporarily during the ignition event to handle voltage stress, then turned off after a predetermined time period. This periodic operation allows the recirculation circuit to provide protection when needed while ensuring that the path is clear for subsequent normal current supply operations, preventing interference with the ignition system's regular function.
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 inhibits excessive voltage stress from being applied to the energy supply circuit, ensuring the longevity and efficiency of the ignition system by promptly recirculating current and managing the recirculation timing to prevent voltage-induced damage.
Implementation Method 1
a primary coil; a secondary coil configured to be magnetically linked to the primary coil
Implementation Method 2
a recirculation circuit configured to permit and prohibit current recirculation through a recirculation path including the predetermined winding
Data Source
AI summary
An ignition device for an internal combustion engine includes: an ignition plug; a primary coil; a secondary coil magnetically linked to the primary coil and connected to the ignition plug; a main ignition circuit causing a spark discharge to occur in the ignition plug; an energy supply circuit that supplies and stops electrical energy to the predetermined winding of the primary coil to accordingly cause the spark discharge to continue; a recirculation circuit that permits and prohibits current recirculation through a recirculation path including the predetermined winding; and a controller configured to: control the main ignition circuit, and determine a start time of a permission of the current recirculation by the recirculation circuit using, as a trigger, the interruption signal which causes the main ignition circuit to interrupt the current through the primary coil, and end the permission after a predetermined time period has elapsed since the start time.