Starter Motor Battery Isolator Control Sequence

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Solution Overview

Problem

Existing electrical systems for motor vehicles require a high-capacity battery isolator to handle the peak current demands of the starter motor, which is costly and complicates integration of a separate starting battery set, and there is a need to prevent overcharging of starting batteries to extend their service life.

Innovation Solution

An electronic control device manages the starter motor and battery isolator to ensure the starting battery set is connected before the starter motor starts and disconnected only after it has stopped, using a standard battery isolator that does not need to handle peak currents, and controls the isolator to disconnect the starting battery set from the generator once it is fully charged.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high-capacity battery isolator is used to handle peak current demands of the starter motor, then the starter motor can be reliably started, but the cost increases and integration of a separate starting battery set becomes more complex

Engineering Contradiction:
Improvereliability of starter motor startingVSAvoidcomplexity of integrating separate starting battery set
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The battery isolator is switched to the on-position before the starter motor is started, ensuring it is ready to handle the peak current demand. This preliminary action allows the use of a standard battery isolator rather than a high-capacity one, reducing cost and complexity while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The battery isolator's switching state is dynamically controlled based on the operational phase of the starter motor. The control device switches the isolator to on-position before starting and off-position after stopping, adapting the electrical connection state to match the current demand requirements.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the battery isolator remains in the on position during starter motor operation, then the starting battery set can be connected, but the battery isolator must handle high peak currents which increases its cost and complexity

Engineering Contradiction:
Improveability to connect starting battery setVSAvoidspecifications of battery isolator
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The battery isolator is switched to the on-position in advance before the starter motor starts, allowing the starting battery set to be connected and charged. The isolator is then switched to the off-position before the starter motor operates, so it does not need to handle the high peak currents during starting, enabling the use of a standard isolator.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The battery isolator's switching state is dynamically adjusted based on the operational phase: on-position during charging phases and off-position during starting phases. This dynamic control allows the starting battery set to be connected and charged without requiring the isolator to handle peak starting currents.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the starting battery set remains connected to the generator during charging, then the batteries can be charged, but overcharging occurs which reduces battery service life and increases water consumption

Engineering Contradiction:
Improvecharging of starting battery setVSAvoidservice life of starting batteries
Core Design Contradiction:
Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The control device monitors the charging state of the starting battery set and uses this feedback to control the battery isolator. When the batteries are fully charged, the control device switches the isolator to the off-position, disconnecting the starting battery set from the generator to prevent overcharging, thereby extending battery service life and reducing water consumption.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The battery isolator's switching state is dynamically controlled based on the charging status of the starting battery set. The isolator is switched to on-position for charging and off-position when charging is complete, preventing overcharging and extending battery life.

Inventive Principle:
Principle #15Dynamics

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 allows the use of a standard, inexpensive battery isolator and prevents overcharging, leading to longer battery life and reduced water consumption, while maintaining efficient starting capabilities without major system restructuring.

Implementation Method 1

a battery isolator (11) which is switchable between an off position in which the battery isolator is adapted to keeping the starting battery set electrically disconnected from the starter motor, and an on position in which the battery isolator is adapted to keeping the starting battery set electrically connected to the starter motor

Methodology Applied
Scientific EffectElectrical switching: Relay

Implementation Method 2

the starter motor is supplied with electric current from a battery to cause the starter motor to rotate the combustion engine's crankshaft

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2250050B1Electrical system for a motor vehicle and method for control of a starter motor and a battery isolator in such an electrical system
Publication Date: 2018.01.10 SCANIA CV AB
  • EP2250050B1 patent drawingFigure 1~2
  • EP2250050B1 patent drawingFigure 3

AI summary

Electric system for a motor vehicle and method for control of a starter motor (10) and a battery isolator (11) in such an electrical system. The electrical system (1) comprises a consumer battery set (2) and a starting battery set (6) which is connected in parallel with the latter. The battery isolator is switchable between an off position in which the starting battery set is electrically disconnected from the starter motor, and an on position in which the starting battery set is electrically connected to the starter motor. An electronic control device (12), upon receiving a starting signal, causes the battery isolator to assume the on position, and thereafter causes the starter motor to start, in order thereby to ensure that the battery isolator is in the on position before the starter motor is started. For switching off of the starter motor, the battery isolator is only allowed to be switched from on position to off position after the starter motor has been switched off, in order thereby to ensure that the starter motor is switched off before the battery isolator is caused to adopt the off position.