Starter Motor Integrated Solid State Switching

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Solution Overview

Problem

Existing starter motor systems rely on starter solenoids, which are prone to failure, require additional assembly steps, and can lead to overheating and costly repairs due to their separate mounting and high current handling needs.

Innovation Solution

Integration of a solid state switching device, such as a MOSFET, within the starter motor to control current flow, replacing the starter solenoid and incorporating thermal, speed, and current limiting circuits for enhanced control and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a starter solenoid is used to control current flow, then the starter motor can be activated, but the system becomes more complex and prone to failure

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the solenoid switching function from the starter motor assembly and implements it separately using solid state switching devices (MOSFETs or IGBTs) with microcontroller control. This separation eliminates the mechanical solenoid while maintaining the switching capability, thereby improving reliability without significantly increasing overall system complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical solenoid system with an electronic solid state switching system. The MOSFETs or IGBTs controlled by a microcontroller substitute for the mechanical contacts and magnetic field-based solenoid operation, eliminating mechanical wear and contact failure modes while reducing assembly complexity through integration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If a starter solenoid is used for high current handling, then the starter motor can operate, but overheating and failure risks increase

Engineering Contradiction:

ImprovepowerVSAvoidoverheating

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the solenoid's high current switching function with solid state power devices (MOSFETs or IGBTs) that have lower on-resistance and better thermal management characteristics. These devices can handle the same power levels with reduced heat generation and improved reliability under high current conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent incorporates temperature sensing and microcontroller-based control that monitors the thermal state of the switching devices. The system can adjust switching parameters or provide cooling activation based on temperature feedback, preventing overheating while maintaining full power capability when needed.

Inventive Principle:

Principle #23Feedback

3Power

If a starter solenoid is mounted separately, then high current handling is achieved, but assembly steps and mounting complexity increase

Engineering Contradiction:

ImprovepowerVSAvoidease of manufacture

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The patent merges the solid state switching devices, control circuitry, and starter motor into a single integrated assembly. The MOSFETs or IGBTs are mounted directly on the starter motor housing or integrated circuit board within the same enclosure, eliminating separate solenoid mounting steps and simplifying the manufacturing process while maintaining high current handling capability.

Inventive Principle:

Principle #5Merging (Combining)

4Ease of operation

If a starter solenoid is used, then current switching is achieved, but maintenance costs and repair frequency increase

Engineering Contradiction:

Improveease of operationVSAvoidease of repair

Core Design Contradiction:

Ease of operationVSEase of repair

Solution Approach 1:

The patent replaces the mechanical solenoid with solid state devices that have no moving parts, contacts, or magnetic fields susceptible to failure. This eliminates the need for solenoid adjustment, contact replacement, or magnetic field calibration, significantly reducing maintenance requirements and repair frequency while maintaining ease of operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solid state switching device reduces assembly complexity, prevents overheating, and enhances reliability by allowing for remote control of the starter motor, thus improving operational safety and reducing maintenance costs.

Implementation Method 1

the solid state switching device includes at least one MOSFET that can be activated by the application of a voltage to the gate of the MOSFET. When the MOSFET is activated, the MOSFET provides a path to ground or the power supply through the starter motor from the battery power supply.

Methodology Applied

Scientific EffectMOSFET switching:

Data Source

PatentUS11111896B2Starter motor with integrated solid state switch

Publication Date: 2021.09.07 BRIGGS & STRATTON CORP

AI summary

A starter motor connected to a power supply and operable to start an internal combustion engine includes an outer housing and a solid state switching device associated with the outer housing. The outer housing encloses a commutator and a series of brushes. The solid state switching device is movable between an open position and a closed position. The current flow from the power supply through the commutator is prevented when the solid state switching device is in the open position.