Multi-Pulse Ignition Control Circuit Voltage Spike Suppression
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Solution Overview
Problem
Existing ignition systems face issues with voltage transients causing improper sparking, which can lead to pre-ignition or engine knocking, and current solutions like high-voltage diodes or additional control circuitry are either costly or undesirable.
Innovation Solution
A multi-pulse drive signal is generated by a control circuit coupled with an engine control unit, which includes a series of pulses with increasing duty cycles and a dwell period, used to regulate current flow through an ignition coil, preventing voltage spikes and reducing sensitivity to signal variations and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-voltage diode is used to suppress voltage spikes, then voltage spike suppression is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the high-voltage diode component from the ignition system by implementing voltage spike suppression through software control of the IGBT switching timing. The turn-on voltage spike is eliminated by delaying the IGBT gate signal until the rectifier diode naturally turns off, avoiding the need for additional suppression components.
Solution Approach 2:
The system uses the natural characteristics of the existing IGBT and rectifier diode to suppress voltage spikes. By carefully timing the IGBT turn-on to coincide with the rectifier diode turn-off, the system self-regulates voltage spikes without requiring external suppression components like high-voltage diodes.
2Reliability
If extra control circuitry is added to suppress voltage spikes, then voltage spike suppression is improved, but device complexity increases
Solution Approach 1:
The existing IGBT control circuit is made multi-functional by programming it to both control the ignition timing and suppress voltage spikes. The same control unit that manages the ignition sequence also implements the voltage spike suppression by adjusting the IGBT gate signal timing, eliminating the need for separate suppression circuitry.
Solution Approach 2:
The control system uses its existing capabilities to suppress voltage spikes by optimizing the IGBT switching timing. The control circuit naturally manages voltage spikes through proper sequencing of the IGBT gate signal with the rectifier diode operation, without requiring additional dedicated suppression circuitry.
3Device complexity
If traditional ignition control is used, then system simplicity is maintained, but pre-ignition and engine knocking occur due to voltage spikes
Solution Approach 1:
The patent implements a multi-pulse drive signal with periodic on-off cycles to charge the ignition coil. The drive signal consists of multiple pulses with increasing duty cycles followed by a dwell period, creating a periodic charging pattern that prevents voltage spikes while maintaining system simplicity.
Solution Approach 2:
The system performs preliminary charging of the ignition coil through multiple pulses before the final spark generation. This preliminary action with increasing duty cycles allows the coil to charge progressively, preventing voltage spikes that would cause pre-ignition while preparing the system for the main spark event.
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 multi-pulse drive signal effectively suppresses voltage spikes, preventing pre-ignition and engine knocking, while reducing the system's sensitivity to pulse duration and temperature variations, thus enhancing the ignition system's reliability and efficiency without the need for additional costly components.
Implementation Method 1
storing energy in an ignition coil using current conducted through the ignition coil by the ignition switch
Implementation Method 2
The control circuit can be configured to provide the multi-pulse drive signal to an ignition switch coupled with the control circuit to receive the multi-pulse drive signal
Data Source
AI summary
In a general aspect, an ignition circuit can include a control circuit that is coupled with an engine control unit (ECU) to receive a command signal from the ECU. The control circuit can include a multi-pulse generator configured to, in response to the command signal, generate a multi-pulse drive signal. The multi-pulse drive signal can include a first pulse cycle having a first duty cycle, a second pulse cycle having a second duty cycle, and a dwell period during which the multi-pulse drive signal continuously remains at a logic high value. The control circuit can be configured to provide the multi-pulse drive signal to an ignition switch coupled with the control circuit to receive the multi-pulse drive signal.