Ignition Coil Voltage Control for Premature Spark Suppression
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Solution Overview
Problem
Existing ignition systems for spark ignited combustion engines face issues with premature sparks due to excessive current surges, high power consumption, and interference in ion current detection, particularly in systems with ion sense circuitry, which often require additional switches that increase costs and reduce reliability.
Innovation Solution
A system and method that control the conductive state of the power switch to maintain a low voltage over the control winding, independent of stored energy, using in-situ voltage measurement to prevent premature sparks and enhance ion sense capabilities by regulating the voltage during the ignition event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If current limiter is used to limit current through primary winding, then power consumption is reduced, but di/dt surge is induced causing premature spark
Solution Approach 1:
The patent applies preliminary action by measuring the voltage across the primary winding before the current reaches the limiting level. The control circuit detects when the voltage indicates approaching current limit and proactively reduces the drive signal to the power transistor, preventing the di/dt surge that would cause premature spark. This anticipatory control avoids the harmful effect before it occurs.
Solution Approach 2:
The patent implements feedback by continuously monitoring the voltage across the primary winding and using this information to adjust the power transistor drive signal. The control circuit creates a closed-loop system where the measured voltage feeds back to the control element, enabling dynamic adjustment of current limiting to prevent both excessive power consumption and premature sparking.
2Loss of energy
If current is limited to reduce power consumption, then battery draining is reduced, but oscillation is produced in circuitry
Solution Approach 1:
The control circuit uses feedback from the primary winding voltage measurement to dynamically adjust the power transistor drive. This feedback mechanism allows smooth current limiting that prevents oscillations by continuously adapting the drive signal rather than applying abrupt current cuts that would cause circuit ringing and oscillations.
Solution Approach 2:
The patent applies dynamics by making the current limiting action adaptive and continuous rather than fixed and abrupt. The control circuit dynamically adjusts the power transistor drive based on real-time voltage measurements, creating a smooth transition that limits power consumption without producing harmful oscillations in the circuitry.
3Measurement precision
If additional switches are added to control ion sense circuitry, then ion current detection is improved, but system complexity and cost increase
Solution Approach 1:
The patent applies universality by making the existing power transistor serve multiple functions: it controls the primary winding current for ignition spark generation and simultaneously controls the voltage for ion sense circuit operation. This multi-functionality eliminates the need for additional switches, reducing system complexity while maintaining precise ion current detection capability through the same control element.
Solution Approach 2:
The patent merges the control functions for ignition spark and ion sensing into a single control circuit that operates the power transistor. By combining these functions, the patent reduces the number of components needed while achieving both ignition and precise ion current measurement, thereby reducing complexity and cost.
4Power
If current surge is allowed for sufficient energy storage, then ignition spark energy is adequate, but spontaneous spark during dwell occurs
Solution Approach 1:
The control circuit uses feedback from primary winding voltage measurements to monitor the energy storage process in real-time. When the voltage indicates that sufficient energy for adequate ignition spark has been stored, the feedback signal triggers the control circuit to limit further current increase, preventing the current surge that would cause spontaneous spark during dwell while maintaining adequate ignition energy.
Solution Approach 2:
The patent applies preliminary action by detecting through voltage measurement when the primary winding has stored sufficient energy for adequate ignition, and proactively limiting current before it reaches levels that would cause spontaneous spark. This anticipatory control ensures adequate ignition energy while preventing harmful spontaneous sparking.
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 prevents premature sparks, reduces power consumption, and improves ion current detection by maintaining a controlled primary current surge and extending the measurement window for ion sense signals, without the need for additional switches.
Implementation Method 1
a control winding magnetically coupled to a secondary winding of an ignition coil
Implementation Method 2
an ignition coil with a primary winding, control winding and a secondary winding magnetically coupled to each other
Data Source
Figure 1~2
Figure 3~4
Figure 5~6b
AI summary
The invention relates to an improved ignition system for spark ignited combustion engines. According to the invention the voltage over a coil winding 6P on the primary side of the ignition coil is regulated to a sufficiently low voltage level during timed periods of the ignition cycle, such that at least one function out of three in total, i.e. prevention of premature spark-on-make, or spark suppression after onset of ignition, or improved frequency response between primary and secondary side of the ignition coil after end of ignition, is obtained. When applied in an inductive ignition system a differential amplifier (8) may be connected over the primary winding 6P regulating a control switch 2CS via a drive unit (9). The invention is preferably implemented in ignition systems with ion sense circuitry 5C,5R on the secondary side of the ignition coil, and implementing all three functions.