Ignition Coil Parallel Circuit Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ignition coil devices face challenges in reducing noise caused by spark discharge while minimizing power consumption, as noise reduction methods like noise reduction resistors and buffer coils either increase power loss or fail to reduce current changes at specific frequency bands due to parasitic capacitance.
Innovation Solution
The proposed ignition coil device incorporates a parallel circuit or magnetic coupling circuit with a series coil and a resistor, where the resistor has a fixed resistance value, reducing impedance changes with frequency and moderating resonance characteristics to alleviate current changes and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a noise reduction resistor is used to reduce conduction noise and radiation noise, then noise is reduced, but power loss increases due to increased electric current in the wiring
Solution Approach 1:
The noise reduction function is segmented into two distinct components: a series coil connected in series with the conducting section, and a resistor connected in parallel with the series coil. This segmentation allows the series coil to handle high-voltage transient suppression while the parallel resistor provides controlled impedance, thereby reducing noise without causing excessive power loss that would occur with a single resistor configuration.
Solution Approach 2:
The invention changes the electrical parameters of the noise reduction circuit by introducing a series coil with specific inductance value and combining it with a parallel resistor. This parameter change creates a frequency-dependent impedance characteristic that reduces noise across different frequency bands while minimizing power consumption, unlike a fixed resistance value that causes continuous power loss.
2Loss of energy
If a buffer coil is used to reduce power loss, then power loss is reduced, but conduction noise and radiation noise are not reduced at specific frequency bands where resonance occurs
Solution Approach 1:
The invention merges the functions of a buffer coil and a noise reduction resistor into a single integrated circuit configuration. The series coil provides buffering action to reduce power loss, while the parallel resistor suppresses resonance at specific frequency bands. This merging of functions ensures that both power loss reduction and noise reduction are achieved simultaneously across all frequency bands.
Solution Approach 2:
The noise reduction circuit uses a composite structure combining inductive elements (series coil) and resistive elements (parallel resistor) to create a circuit with combined characteristics. This composite approach allows the circuit to exhibit both buffering properties for power loss reduction and damping properties for noise reduction across different frequency ranges.
3Object-affected harmful factors
If impedance is increased to reduce current change during spark discharge, then noise is reduced, but power consumption increases
Solution Approach 1:
The noise reduction circuit provides dynamic impedance characteristics through the combination of the series coil and parallel resistor. The impedance varies with frequency, providing high impedance at resonance frequencies to reduce noise while maintaining lower impedance at other frequencies to minimize power consumption. This dynamic behavior allows the circuit to adaptively reduce noise only when necessary.
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 effectively reduces conduction and radiation noise caused by spark discharge while maintaining sufficient impedance, thereby minimizing power consumption and noise across various frequency bands.
Implementation Method 1
a secondary coil configured to generate a voltage that causes spark discharge at a spark plug by boosting a voltage applied from the power source
Implementation Method 2
the resistor has a fixed resistance value, reducing impedance changes with frequency
Implementation Method 3
moderating resonance characteristics to alleviate current changes and noise generation
Implementation Method 4
An instant change of the electric current caused by the spark discharge induces a conduction noise in a component of the ignition coil device
Implementation Method 5
a radiation noise induced by the conduction noise is radiated from the component of the ignition coil device
Data Source
AI summary
An ignition coil device includes a primary coil, a switching member, a secondary coil and a parallel circuit. The primary coil is to be connected to an external power source. The switching member switches an on state and an off state of electric power supply from the power source to the primary coil. The secondary coil generates a voltage that causes spark discharge at a spark plug as the electric power supply from the power source is switched from the on state to the off state by the switching member. The parallel circuit includes a series coil and a resistor. The series coil is connected in series with a conducting section that electrically connects the secondary coil to the spark plug. The resistor is connected to the conducting section in parallel with the series coil and having a fixed electric resistance value.