Ignition Apparatus Discharge Path Stabilization
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Solution Overview
Problem
Lean-burn engines experience variations in engine output torque due to inconsistent spark discharge path lengths, which are affected by air-fuel mixture flow, leading to differing combustion states.
Innovation Solution
An ignition apparatus with a boost transformer, measurement unit, and controller that adjusts the electric current supplied to the ignition plug based on discharge state, reducing drive current when the discharge path is excessively extended to promote a short circuit and maintain a consistent discharge path length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the discharge time in the ignition plug is set to be long to improve ignitability in lean state, then the ignitability is improved, but the discharge path length becomes excessively extended due to air-fuel mixture flow, causing variation in combustion state and engine output torque
Solution Approach 1:
The patent employs a feedback mechanism where the discharge current is monitored and used to control the current supplied to the primary coil. When the discharge path becomes excessively extended (indicated by reduced discharge current), the system automatically reduces the primary coil current to shorten the discharge path, thereby maintaining consistent discharge characteristics and combustion state across multiple combustion cycles
Solution Approach 2:
The patent dynamically adjusts the current supplied to the primary coil based on the actual discharge conditions. By making the ignition system adaptive rather than static, the discharge path length is continuously optimized to maintain consistency despite variations in air-fuel mixture flow, resolving the contradiction between extended discharge time for ignitability and discharge path length stability
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 stabilizes the discharge path length, reducing variations in discharge shape between combustion cycles and improving engine torque consistency.
Implementation Method 1
The boost transformer has a primary coil and a secondary coil magnetically coupled with each other. The boost transformer is configured to supply the ignition plug with the electric power that is generated in the secondary coil by electromagnetic induction upon supply of AC power to the primary coil.
Data Source
AI summary
An ignition apparatus includes an ignition plug, a boost transformer, an ignition power source and a measurement unit. The ignition plug has a center electrode and a ground electrode. The boost transformer supplies the ignition plug with electric power generated in a secondary coil upon supply of AC power from the ignition power source to a primary coil. The measurement unit measures the discharge voltage of the ignition plug. The ignition power source includes a discharge state determining unit that determines the discharge state of the ignition plug based on the measured discharge voltage and a current controlling unit that controls electric current supplied to the primary coil. When a discharge path formed between the center and ground electrodes of the ignition plug is determined by the discharge state determining unit as being in an over-extended state, the current controlling unit reduces the electric current supplied to the primary coil.