Blower Housing Starter Assembly for Heat-Isolated Engine Cranking

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Solution Overview

Problem

Conventional electric starting systems for outdoor power equipment require a specialized engine block and flywheel with a ring gear, which is not compatible with recoil starting systems, and often expose the starter motor to heat and vibration, reducing its longevity and reliability.

Innovation Solution

An electric starting system where the starter motor and battery are integrated into the blower housing, positioned away from hot components, and utilize a worm gear and clutch mechanism to provide a soft start feature, allowing for a higher-speed, lighter, and more compact electric motor with reduced vibration and heat exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the starter motor is mounted to the engine block with a specialized mounting location, then the electric starting system can be implemented, but the device complexity increases and compatibility with recoil starting systems is lost

Engineering Contradiction:
Improvecompatibility with recoil starting systemsVSAvoidengine block complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The blower housing is designed to serve multiple functions: it houses the blower fan for engine cooling and simultaneously serves as the mounting structure for the electric starting system. This eliminates the need for specialized engine block modifications and maintains compatibility with recoil starting systems while enabling electric start functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the starter motor is positioned near the engine block for direct engagement, then the starting mechanism is simplified, but the starter motor is exposed to heat and vibration reducing its longevity

Engineering Contradiction:
Improvestarter motor longevityVSAvoidstarting system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blower housing acts as an intermediary structure that couples the starter motor to the engine's flywheel. The starter motor is mounted to the blower housing rather than directly to the engine block, which isolates it from heat and vibration while still enabling mechanical engagement with the flywheel through the housing's structural connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If a conventional starter motor is used with direct engine block mounting, then the system structure is simplified, but the starter motor experiences higher vibration and heat exposure

Engineering Contradiction:
Improveheat and vibration exposureVSAvoidsystem assembly simplicity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The electric starting system components (starter motor, battery, control circuitry) are integrated into the blower housing assembly. This merging of functions allows the housing to protect the starter motor from harmful environmental factors while maintaining manufacturing efficiency through consolidated assembly procedures.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables the use of a high-speed, lightweight electric motor that efficiently starts the engine while minimizing vibration and heat exposure, leading to improved reliability and longevity of the electric starting system components.

Implementation Method 1

an electric motor configured to be powered by the battery and rotate the crankshaft to rotate (crank) the engine

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

A worm is coupled to the electric motor and rotates a worm wheel. The worm wheel is configured to rotate about the crankshaft axis and selectively drive the crankshaft via the clutch and the flywheel protrusions

Methodology Applied
Scientific EffectWorm drive mechanism: Worm Drive

Implementation Method 3

The clutch is coupled to the worm gear and turns therewith. Engagement of the clutch with the flywheel cup drives the flywheel and causes the starting of the engine

Methodology Applied
Scientific EffectFriction engagement: Friction

Data Source

PatentEP3821121B1Internal combustion engine with electric starting system
Publication Date: 2024.02.28 BRIGGS & STRATTON CORP
  • EP3821121B1 patent drawingFigure 1
  • EP3821121B1 patent drawingFigure 2
  • EP3821121B1 patent drawingFigure 3

AI summary

An engine including an engine block having a cylinder defining a front of the engine, a blower housing coupled to the engine block and defining a hot half and a cool half opposite the front half, a starter mount assembly coupled to the blower housing and positioned within the cool half, an electric starter motor retained by the starter mount assembly, and a battery mounted to the blower housing and positioned in the cool half. The battery is electrically coupled to the electric starter motor.