Linked Venturi Insert for Carburetor Fuel Delivery Alignment

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Solution Overview

Problem

In multiple throttle bore carburetors for small utility engines, ensuring consistent fuel delivery to each cylinder is challenging due to the independent construction and orientation of venturi tubes, which can shift during operation, affecting engine performance.

Innovation Solution

A flexible and resilient venturi insert system comprising linked venturi tubes with fuel ports, designed to be securely mounted within the carburetor body, allowing for precise alignment and maintaining optimal orientation through a flexible linking member that biases the tubes back into position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If independent venturi tubes are used in multiple throttle bore carburetors, then each cylinder can have customized fuel delivery, but the venturi tubes can shift during operation affecting consistency

Engineering Contradiction:
Improvecustomized fuel deliveryVSAvoidspatial orientation consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Multiple independent venturi tubes are merged into a single integrated insert assembly that is secured as one unit within the carburetor body. This combining approach maintains the individual customization of each venturi tube while preventing relative movement between tubes, thereby ensuring consistent spatial orientation and reliable fuel delivery to each cylinder.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If venturi tubes are independently constructed, then fuel delivery can be optimized for each cylinder, but installation and alignment become complex

Engineering Contradiction:
Improvefuel delivery optimizationVSAvoidinstallation and alignment
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The venturi tubes are combined into a single pre-assembled insert unit with integrated positioning features. This allows the complex multi-tube assembly to be installed as one piece, significantly simplifying the installation process while maintaining the ability to optimize fuel delivery for each individual cylinder through the design of the insert as a whole.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If venturi tubes are fitted into throttle bores, then fuel metering is achieved, but the tubes may not stay in correct spatial orientation

Engineering Contradiction:
Improvefuel metering functionVSAvoidspatial orientation maintenance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

An intermediary insert assembly is introduced between the venturi tubes and the carburetor body. This insert serves as a mediator that provides precise positioning features and retention mechanisms, ensuring that the venturi tubes maintain their correct spatial orientation during operation while still allowing for fuel metering functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 venturi insert system ensures consistent fuel delivery to each cylinder by maintaining precise alignment and orientation, enhancing engine performance and efficiency by allowing for easy installation and secure retention of venturi tubes within the carburetor body.

Implementation Method 1

The venturi tube in this type of carburetor design is the component that meters fuel into the carburetor air stream by restricting the air flow slightly via a throat section, thereby creating a pressure differential that draws fuel from a fuel delivery passage of the carburetor body through a fuel port

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

introduce fuel to the carburetor air stream via a venturi passage that is created when a 'hollow' venturi tube is pressed or otherwise fitted into a throttle bore

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentEP2713037B1Venturi insert for a carburetor, and carburetor, system and apparatus incorporating the same
Publication Date: 2018.09.05 KOHLER CO(US)
  • EP2713037B1 patent drawingFigure 1
  • EP2713037B1 patent drawingFigure 2
  • EP2713037B1 patent drawingFigure 3

AI summary

A venturi insert for a carburetor, and a carburetor, system and apparatus incorporating the same. In one embodiment, the invention is a carburetor for an internal combustion engine comprising: a carburetor body comprising a plurality of throttle bores extending through the carburetor body, and for each of the throttle bores a fuel delivery passage terminating at a sidewall of the throttle bore; an insert comprising a plurality of venturi tubes and a linking member connecting the venturi tubes together, each of the venturi tubes comprising a venturi passage and a fuel port for introducing fuel into the venturi passage; and the insert secured to the carburetor body so that the venturi tubes extend into the throttle bores and the fuel ports are in fluid communication with the fuel delivery passages, and the linking member is in contact with the carburetor body.