Ignition Apparatus Blow-off Detection and Energy Control
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Solution Overview
Problem
Conventional ignition apparatuses for internal combustion engines face issues with re-discharge blow-off, leading to electrode wear and misfires, particularly in lean-burn engines with strong gas flows, as they fail to effectively control energy input and suppress blow-off without unnecessary energy consumption.
Innovation Solution
An ignition apparatus with a blow-off detection system that divides the energy input period into two regions, allowing re-discharge in the first region where inductive energy remains and stopping energy input in the second region where energy is depleted, thereby preventing unnecessary wear and maintaining ignition performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gas flow is strengthened to improve combustibility in lean-burn engines, then the discharge is extended and ignition performance is improved, but blow-off of the discharge occurs and electrode wear increases
Solution Approach 1:
The control unit performs preliminary detection of blow-off occurrence during the discharge period, and based on this detection, determines whether to permit re-discharge. This preliminary action prevents unnecessary re-discharge that would cause electrode wear while ensuring ignition reliability when needed.
Solution Approach 2:
The control unit uses feedback from blow-off detection (based on secondary electric current characteristics) to control the energy input means. When blow-off is detected, the system adjusts subsequent energy input to prevent unnecessary re-discharge, thereby reducing electrode wear while maintaining ignition performance.
2Object-affected harmful factors
If re-discharge is inhibited whenever blow-off occurs to prevent electrode wear, then electrode wear is suppressed, but misfire occurs when air-fuel mixture has not been ignited before blow-off
Solution Approach 1:
The control unit uses feedback from blow-off detection to make intelligent decisions about re-discharge. Based on detecting blow-off characteristics during discharge, the system determines whether re-discharge is necessary for ignition or should be suppressed to prevent wear, thus resolving the contradiction between reliability and wear prevention.
Solution Approach 2:
The system dynamically adjusts the re-discharge control strategy based on real-time detection of blow-off occurrence and timing. The control unit permits or inhibits re-discharge according to the specific situation, making the system adaptive rather than fixed, thereby balancing ignition reliability and electrode wear prevention.
3Reliability
If energy input is continued after blow-off to ensure re-discharge capability, then ignition reliability is maintained, but unnecessary energy consumption occurs
Solution Approach 1:
The control unit uses feedback from blow-off detection to control energy input timing and amount. When blow-off is detected, the system adjusts energy input based on whether re-discharge is necessary, thereby avoiding unnecessary energy consumption while maintaining ignition reliability when needed.
Solution Approach 2:
The control unit changes energy input parameters (timing, duration, amount) based on blow-off detection results. By adjusting these parameters dynamically, the system optimizes energy consumption to match actual ignition needs, preventing waste while ensuring reliability.
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 determines the permissibility of re-discharge based on blow-off timing, reducing electrode wear and energy consumption while ensuring reliable ignition, even in varying engine conditions.
Implementation Method 1
a secondary coil which is connected to an electrode of the ignition plug and in which a secondary voltage is generated by supply and interruption of the primary electric current, more specifically by interruption following supply of the primary electric current, and thus a secondary electric current flows
Data Source
AI summary
An ignition apparatus inputs energy during a predetermined energy input period after the interruption of a primary electric current by an ignition switch and a discharge of an ignition plug caused by a secondary electric current. Moreover, the ignition apparatus includes a blow-off detection unit that detects, during the energy input period IGW after the start of the discharge by the ignition plug, occurrence of blow-off of the discharge. When the secondary electric current I2 drops below a blow-off detection electric current threshold value Ibo at a time instant tbo in a “second region” where it is impossible to perform a re-discharge after blow-off, the blow-off detection unit determines that blow-off has occurred and the ignition apparatus stops the energy input from an energy input unit to an ignition coil. By preventing unnecessary energy input, it is possible to suppress unnecessary electric power consumption and wear of electrodes of the ignition plug.