Ignition Coil Voltage Modulation for Advance Spark Prevention
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Solution Overview
Problem
Existing electronic ignition systems for internal combustion engines face issues with high voltage peaks leading to advance sparks, poor control accuracy during the plasma step, and significant thermal-power dissipation, resulting in reduced reliability and increased misfiring events.
Innovation Solution
An electronic ignition system with a voltage changing element and current detection means, coupled with an accumulation circuit and ionization current measurement, to modulate the switch driving signal based on real-time current values and optimize the plasma control, reducing thermal dissipation and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the turn ratio between primary and secondary windings is increased to enable efficient forward steps, then plasma generation efficiency is improved, but high voltage peaks are generated that can break the dielectric in the gap causing advance sparks
Solution Approach 1:
The control unit performs preliminary action by detecting the voltage across the spark plug gap before the forward step and comparing it to a reference value. Based on this preliminary detection, the control unit decides whether to enable or disable the forward step, preventing advance spark from occurring in the first place
Solution Approach 2:
The control unit implements feedback by continuously monitoring the voltage across the spark plug gap and using this information to control the switching of the primary winding. The detected voltage feedback allows the system to adjust the forward step operation to maintain plasma generation while preventing dielectric breakdown
2Productivity
If the switch is controlled at high frequencies during the plasma step to maintain spark, then combustion completeness is improved, but thermal-power dissipation increases reducing reliability
Solution Approach 1:
The control unit applies partial action by selectively enabling the forward step only when the detected voltage across the gap is below the reference value. Instead of continuously operating at high frequency, the system applies switching action only when needed to maintain plasma, reducing unnecessary thermal dissipation
Solution Approach 2:
The control unit changes the operating parameters of the primary winding by dynamically adjusting the switching frequency and duty cycle based on real-time voltage detection. This parameter adaptation allows the system to maintain combustion completeness while operating at lower power dissipation levels
3Ease of operation
If predefined logic is used to control switch opening and closing during plasma step, then control simplicity is maintained, but control accuracy deteriorates due to inability to respond to real cylinder conditions
Solution Approach 1:
The control unit implements feedback control by detecting the actual voltage across the spark plug gap in real-time and using this information to control the switching of the primary winding. This closed-loop approach maintains control simplicity while dramatically improving accuracy by responding to actual cylinder conditions
Solution Approach 2:
The system replaces predefined mechanical logic with electronic sensing and control. The control unit uses electronic voltage detection and conditional switching logic to adapt to real-time conditions, substituting rigid predefined sequences with flexible electronic control that maintains both simplicity and accuracy
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
The system effectively minimizes advance sparks, enhances control accuracy, reduces thermal-power dissipation, and minimizes misfiring events, resulting in a more reliable and efficient ignition process.
Implementation Method 1
by electromagnetic induction, the primary winding discharges on the secondary, charging it at a voltage which is high enough to break the dielectric in the 'gap' between the two electrodes, generating the spark
Implementation Method 2
transferring power through the coil to the secondary winding, generating again a high voltage of opposite sign from the previous one, thus keeping the spark in the 'gap' 'alive'
Implementation Method 3
the voltage alternating command ensures the flow of electrons through the discharge 'gap' such that the effect of avalanche ionization occurs
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An electronic ignition system for an internal combustion engine comprises an ignition coil (2) provided with at least a primary winding (3) and a secondary winding (4), a switch (6) connected to the primary winding (3) and drivable in an open and/or closed position according to the value of a driving signal, a control unit (7) associated to the switch (6) and configured to drive it in open and/or closed position according to the value of the driving signal (G). Such system also comprises a voltage changing electronic element (8) connected to the electrical connection (5), operatively interposed between the electrical connection (5) and the primary winding (3), and configured to change the voltage value of the primary winding (3) according to the value of a control signal between at least a first (V1 ) and a second (V2) voltage value. The system also comprises a ionization measuring device (20) around said discharge gap (100a) of the spark plug (100) associated with the secondary winding (4) and arranged to detect a current value in the secondary winding (4) and to send a signal representative of said value to the control unit (7), wherein the control unit (7) is configured to activate said measuring device (20) upon the shutdown of the electric arc or spark.