Starter Delay Circuit for Battery Voltage Stability

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Solution Overview

Problem

Conventional starters experience unstable voltage drops at the battery terminal during motor startup, leading to 'temporary blackouts', especially exacerbated by idling stop devices in vehicles, due to varying motor reverse voltage affecting current flows.

Innovation Solution

A starter design featuring a motor, pinion gear, first and second electromagnetic switches, and a control device that manages the timing of these switches to maintain a stable initial current flow through a resistor, independent of motor reverse power, with the second current flow adjusted based on temperature to prevent voltage drops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a current suppressing resistor is used to reduce rush current during motor startup, then the initial current is reduced and battery terminal voltage is stabilized, but the delay time must be precisely controlled to ensure the second current peak does not exceed the first current peak

Engineering Contradiction:
Improvebattery terminal voltage stabilityVSAvoidcontrol timing precision
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A delay circuit is introduced as an intermediary component between the first and second electromagnetic switches. This delay circuit automatically controls the timing of the second switch to close after the first switch, providing the precise delay needed without complex control mechanisms. The delay circuit acts as a mediator that manages the current suppression timing, ensuring the second current peak does not exceed the first current peak while maintaining battery terminal voltage stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the delay time is set to allow stable current suppression, then voltage drop is reduced, but the circuit becomes more complex requiring precise timing control

Engineering Contradiction:
Improvevoltage dropVSAvoidtiming control mechanism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The delay circuit is designed to automatically determine and execute the optimal delay time without requiring external control or complex timing mechanisms. The circuit self-regulates the timing of the second electromagnetic switch based on the state of the first switch and the motor circuit, providing stable current suppression and voltage drop reduction while keeping the control mechanism simple and self-contained.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If a simple delay circuit is used, then manufacturing cost is reduced, but the ability to adapt to varying motor reverse voltage and temperature conditions is limited

Engineering Contradiction:
Improvemanufacturing costVSAvoidtemperature and voltage adaptation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The delay circuit is designed to automatically adjust its delay time based on changing operating conditions such as temperature and motor reverse voltage. By changing the delay time parameter dynamically, the circuit adapts to varying conditions without requiring complex sensing or control mechanisms. This allows the simple delay circuit to maintain effective current suppression across different temperature and voltage conditions, achieving adaptability while keeping manufacturing costs low.

Inventive Principle:
Principle #35Parameter changes

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 battery terminal voltage, reduces the occurrence of 'temporary blackouts', and simplifies the circuit configuration, reducing manufacturing costs and allowing for compact design.

Implementation Method 1

a first electromagnetic switch that opens and closes a first contact point provided on a motor circuit for applying a current from a battery to the motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a resistor that is connected to the motor circuit in series with the first contact point

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP2128426B8Starter having delay circuit
Publication Date: 2015.07.08 DENSO CORP

AI summary

A starter includes an electromagnetic switch that opens and closes a main contact point provided on a motor circuit, a current suppressing resistor that is connected to the motor circuit in series with the main contact point, a short-circuit relay that is provided to allow short-circuiting of the current suppressing resistor, a timer circuit that delays operation of the short-circuit relay, and the like. The timer circuit sets a delay time from when the electromagnetic switch is energized until the short-circuit relay is energized. The delay time is set such that a maximum value of the current flowing to the motor when the short-circuit relay is energized is equal to or less than a maximum current value of current flowing to the motor when the electromagnetic switch is energized.