Electronic Ignition Transformer Discharge Circuit

Solution Overview

Problem

Existing electronic ignition systems for vehicles face challenges in safely discharging energy from the primary winding during failures, leading to potential engine and component damage due to spurious sparks, as current solutions require long time intervals to gradually reduce voltage, which can cause thermal issues and fail to reliably prevent sparks.

Innovation Solution

An electronic protection circuit that includes a current generator and voltage clamping circuit, enabling a fast initial discharge followed by a controlled slow discharge to clamp the primary voltage to a predetermined value, thereby reducing the time to activate protection systems and preventing high peak currents and spurious sparks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the system uses a long time interval to gradually reduce voltage during failure, then spurious sparks are prevented, but thermal damage occurs and protection activation is delayed

Engineering Contradiction:

Improveprevention of spurious sparksVSAvoidthermal damage

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The discharge process is segmented into two distinct phases: a first phase with fast discharge current to quickly reduce voltage and prevent thermal damage, and a second phase with slow discharge current to gradually reduce voltage and prevent spurious sparks. This segmentation allows each phase to optimize for its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements periodic action by switching between two different discharge modes based on the operational phase. The control unit activates the appropriate discharge current magnitude based on whether the system is in the first phase (high current for fast discharge) or second phase (low current for controlled discharge), creating a time-based periodic control strategy.

Inventive Principle:

Principle #19Periodic action

2Reliability

If the system uses a long time interval to gradually reduce voltage, then spurious sparks are prevented, but protection system activation time is increased

Engineering Contradiction:

Improveprevention of spurious sparksVSAvoidprotection activation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The protection activation process is segmented into two stages: initial fast activation using high discharge current to quickly establish protection, followed by gradual voltage reduction using low discharge current. This segmentation enables the system to activate protection rapidly while still achieving the gradual discharge needed to prevent sparks.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary action by first activating the protection circuit with high discharge current to immediately clamp the voltage and prevent thermal damage, then transitioning to the gradual discharge phase. This preliminary fast discharge ensures protection is activated quickly before the controlled discharge phase begins.

Inventive Principle:

Principle #10Preliminary action

3Speed

If the system rapidly discharges energy from primary winding, then protection activation is fast, but spurious sparks may occur

Engineering Contradiction:

Improveprotection activation speedVSAvoidspurious sparks

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The discharge process is segmented into two distinct phases: a first phase with fast discharge current to quickly reduce voltage and prevent thermal damage, and a second phase with slow discharge current to gradually reduce voltage and prevent spurious sparks. This segmentation allows each phase to optimize for its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements periodic action by switching between two different discharge modes based on the operational phase. The control unit activates the appropriate discharge current magnitude based on whether the system is in the first phase (high current for fast discharge) or second phase (low current for controlled discharge), creating a time-based periodic control strategy.

Inventive Principle:

Principle #19Periodic action

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 solution reduces the time interval to clamp the primary winding voltage, preventing thermal damage and reliably avoiding spurious sparks, while ensuring a gradual energy discharge to prevent engine component failure.

Implementation Method 1

The coil is a transformer which is such to generate a voltage across the secondary winding greater than the voltage across the primary winding

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

it is necessary to gradually discharge the energy stored into the primary winding by gradually reducing the value of the charge current flowing through the primary winding of the coil

Methodology Applied

Scientific EffectResistive heating: Joule Heating

Data Source

PatentUS9130366B2Electronic ignition system for an engine of a vehicle in case of failure

Publication Date: 2015.09.08 STMICROELECTRONICS SRL

AI summary

An electronic system to discharge a transformer in case of a failure during a charging phase of the transformer. The system includes the transformer having a primary winding with a first terminal connected to a battery voltage and with a second terminal for generating a primary voltage signal, includes a switch serially connected to the primary winding and having a control terminal carrying a control voltage signal for opening or closing the switch and includes an electronic circuit. The electronic circuit further includes a current generator and a voltage clamping.