Ignition Device Streamer Discharge Control for Electrode Wear
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Solution Overview
Problem
Existing ignition devices for internal combustion engines consume electrodes rapidly due to the high current required for wide discharge plasma, leading to premature electrode wear.
Innovation Solution
An ignition device with a voltage applying unit that sets alternating current voltage frequency to induce voltage resonance, favoring streamer discharge over arc discharge when the air/fuel ratio is rich, minimizing electrode exposure to high temperatures and consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large amount of current is supplied to increase the area of discharge plasma, then the discharge plasma area is increased, but the electrode consumption increases significantly
Solution Approach 1:
The patent changes the electrical parameters by applying alternating current voltage with a specific frequency that produces voltage resonance in the circuit. This resonance effect enables streamer discharge to occur at lower current levels compared to conventional arc discharge, thereby expanding the discharge plasma area without proportionally increasing electrode consumption. The frequency control allows transition between different discharge modes (streamer vs arc) to optimize the balance between plasma area and electrode wear.
2Loss of substance
If alternating current voltage with resonance frequency is applied to produce streamer discharge, then electrode consumption is reduced, but the ignitability of fuel may be compromised
Solution Approach 1:
The patent employs dynamic control of the alternating current frequency to adapt to different operating conditions. By dynamically adjusting the frequency to maintain voltage resonance, the system can switch between streamer discharge (for fuel ignition) and arc discharge (for high-temperature combustion) modes. This dynamic parameter adjustment ensures that the discharge type matches the combustion requirements while minimizing electrode consumption during the ignition phase.
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 solution effectively reduces electrode consumption by using streamer discharge for fuel combustion when the air/fuel ratio is low, maintaining ignitability and extending electrode life by preventing frequent exposure to high temperatures.
Implementation Method 1
a frequency of the alternating current voltage being set so as to produce voltage resonance in a circuit including the ignition plug and the secondary coil
Implementation Method 2
supplies a primary current to a primary coil electrically connected to a power source so as to store magnetic energy in an ignition coil. Then, a secondary current is induced when the primary current is cutoff
Implementation Method 3
a partial breakdown start to occur due to a discharge at the pair of discharge electrodes
Implementation Method 4
a total breakdown occurs due to a discharge at the pair of discharge electrodes
Data Source
AI summary
An ignition device includes: an ignition plug producing plasma discharge between a pair of discharge electrodes of an ignition plug; an ignition coil provided with a primary coil and a secondary coil, the secondary coil applying voltage between the pair of discharge electrodes; a voltage applying unit applying alternating current voltage to the primary coil, a frequency of the alternating current voltage being set to produce voltage resonance in a circuit including the ignition plug and the secondary coil. The voltage applying unit sets an output period of the alternating current voltage to be longer than a first period at which a partial breakdown start to occur at the pair of discharge electrodes, and shorter than a second period at which a total breakdown occurs at the pair of discharge electrodes, when an air/fuel ratio is lower than a predetermined threshold.