Ignition Coil Controller for Discharge Plasma Length Estimation
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Solution Overview
Problem
Existing methods for controlling internal combustion engines with ignition coils lack an accurate method to estimate discharge plasma length, which is crucial for maintaining combustion stability, especially in high dilution combustion conditions where the stable combustion region is narrow.
Innovation Solution
A controller and control method that includes a secondary voltage detector, a minimum value calculator, and a discharge plasma length calculator to accurately estimate the discharge plasma length based on secondary voltage and its minimum value, allowing for optimal operation of in-cylinder flow and ignition energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output energy of the ignition coil is increased to stabilize combustion in high dilution conditions, then combustion stability is improved, but the discharge plasma is flowed and extended by in-cylinder flow, causing plasma blow-off and reducing ignition reliability
Solution Approach 1:
The system detects secondary voltage and secondary current from the ignition coil, calculates discharge plasma length in real-time, and feeds this information back to control the ignition coil output energy and injection valve timing, creating a closed-loop control system that adapts to varying plasma extension conditions
Solution Approach 2:
The system dynamically adjusts ignition coil output energy and injection valve opening timing based on calculated discharge plasma length, changing operational parameters to maintain optimal combustion stability while preventing plasma blow-off under different in-cylinder flow conditions
2Reliability
If the discharge plasma is allowed to extend by in-cylinder flow to activate fuel-air mixture, then combustion stability in high dilution conditions is improved, but accurate control becomes difficult without precise plasma length measurement
Solution Approach 1:
The system replaces direct physical measurement of discharge plasma length with electrical parameter detection (secondary voltage and current) and mathematical calculation, substituting mechanical/optical measurement with an electrical sensing and computation approach
Solution Approach 2:
The system uses secondary voltage and secondary current as intermediary parameters that correlate with discharge plasma length, allowing indirect measurement of plasma extension through easily detectable electrical quantities rather than direct physical measurement
3Reliability
If ignition energy is increased to prevent plasma blow-off, then ignition reliability is improved, but fuel efficiency decreases due to excessive energy consumption
Solution Approach 1:
The system dynamically adjusts ignition coil output energy based on real-time discharge plasma length calculation, transitioning from fixed high energy input to variable energy input that matches actual plasma extension needs, optimizing the balance between ignition reliability and energy efficiency
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 enables improved combustion stability by accurately calculating discharge plasma length, preventing plasma blow-off and ensuring stable ignition, even in high dilution combustion scenarios.
Implementation Method 1
an ignition coil which has a primary coil to which power is supplied from a direct current power source and a secondary coil which has more winding number than the primary coil and generates high voltage supplied to the ignition plug
Implementation Method 2
a secondary coil which has more winding number than the primary coil and generates high voltage supplied to the ignition plug
Implementation Method 3
the spark discharge (here, it means a dielectric breakdown and a subsequent formation of discharge plasma) is generated between the gap of the ignition plug
Implementation Method 4
the discharge plasma which occurs between the gap of the ignition plug is flowed and extends long by the in-cylinder flow
Data Source
AI summary
To provide a controller and a control method for an internal combustion engine capable of estimating a discharge plasma length accurately by easy method. Controller for internal combustion engine is provided with a secondary voltage detector that detects secondary voltage which is voltage generated by secondary coil, a secondary voltage minimum value calculator that calculates minimum value of secondary voltage during discharge period, and a discharge plasma length calculator that calculates length of the discharge plasma based on secondary voltage and minimum value of secondary voltage.