Diaphragm Pump With Asymmetric Pressure Amplification

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Solution Overview

Problem

Existing diaphragm pumps are limited in their ability to pressurize fuel beyond the internal pressure of the crank chamber, necessitating further improvements to enhance fuel supply to fuel injection devices.

Innovation Solution

A diaphragm pump design featuring a low pressure side diaphragm and a high pressure side diaphragm connected via a connecting portion, where the high pressure side diaphragm operates in conjunction with the low pressure side diaphragm, with a smaller area of operation, allowing it to apply higher pressure to the fuel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a single diaphragm is used to receive pulsating pressure from the crank chamber, then the structure is simple, but the fuel pressure cannot exceed the crank chamber internal pressure

Engineering Contradiction:
Improvefuel pressureVSAvoiddiaphragm structure
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The single diaphragm is divided into two separate diaphragms: a low pressure side diaphragm that receives pulsating pressure from the crank chamber, and a high pressure side diaphragm that pressurizes the fuel. This segmentation allows each diaphragm to perform a specific function, enabling fuel pressure to exceed crank chamber pressure while maintaining structural simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A connecting portion is introduced as an intermediary element to transmit the operating force from the low pressure side diaphragm to the high pressure side diaphragm. This mediator enables the two diaphragms to work in conjunction, allowing the high pressure side diaphragm to amplify the pressure beyond the crank chamber internal pressure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stress or pressure

If the high pressure side diaphragm has the same area as the low pressure side diaphragm, then the structure is symmetric and simple, but the pressure amplification effect cannot be achieved

Engineering Contradiction:
Improvepressure amplificationVSAvoiddiaphragm area configuration
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The diaphragms are designed with asymmetric areas: the low pressure side diaphragm has a larger area to receive sufficient pulsating pressure from the crank chamber, while the high pressure side diaphragm has a smaller area to amplify the pressure. This asymmetric configuration creates the pressure amplification effect necessary to exceed crank chamber internal pressure

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The area parameter of the diaphragms is specifically optimized: the low pressure side diaphragm area is designed to maximize pressure reception from the crank chamber, while the high pressure side diaphragm area is reduced to achieve pressure amplification. This parameter optimization enables the pressure increase function

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

The design enables further pressurization of fuel, ensuring efficient fuel supply to fuel injection devices, while maintaining stable operation of both diaphragms through backup structures.

Implementation Method 1

a low pressure side diaphragm (10) forming a part of a pulsation operating chamber (R11) to which the pulsating pressure is transmitted and configured to operate by receiving the pulsating pressure

Methodology Applied
Scientific EffectPulsating pressure: Pressure Increase

Implementation Method 2

an area of the high pressure side operating portion (20a) is smaller than an area of the low pressure side operating portion (10a), allowing the high pressure side diaphragm to apply a pressure higher than the pulsating pressure in the crank chamber

Methodology Applied
Scientific EffectPressure amplification through area difference: Pressure Increase

Data Source

PatentEP4286678B1Diaphragm pump
Publication Date: 2025.08.13 MARUYAMA MFG CO INC
  • EP4286678B1 patent drawingFigure 1
  • EP4286678B1 patent drawingFigure 2
  • EP4286678B1 patent drawingFigure 3

AI summary

A diaphragm pump (1) operates by receiving a pulsating pressure in a crank chamber (2a) of an engine (2). The diaphragm pump includes a low pressure side diaphragm (10) that operates by receiving a pulsating pressure, a high pressure side diaphragm (20) that sends fuel to an engine, and a connecting portion (30) that connects the low pressure side diaphragm and the high pressure side diaphragm to each other. An area of a high pressure side operating portion (20a) of the high pressure side diaphragm is smaller than an area of a low pressure side operating portion (10a) of the low pressure side diaphragm.