High Pressure Pump Cylinder Design for Housing Rigidity

Solution Overview

Problem

High pressure pumps face challenges in maintaining rigidity and preventing deformation due to high fuel pressures, leading to increased housing sizes and complexities in design to manage pressure forces effectively.

Innovation Solution

A high pressure pump design featuring a bottomed tubular cylinder with an inner and outer peripheral wall, where the pressurizing chamber is formed by the inner peripheral wall, inner bottom wall, and the distal end outer wall of the plunger, allowing the pressure force to be directed upward and limiting movement of the cylinder relative to the housing, reducing the need for extensive housing rigidity and size increases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the pressurizing chamber is formed by the end surface of the plunger and the inner wall of the housing, then the fuel pressure is applied to the inner wall of the housing, but the housing size must be increased to achieve sufficient rigidity against high fuel pressure

Engineering Contradiction:

Improvefuel pressureVSAvoidhousing size

Core Design Contradiction:

Stress or pressureVSVolume of stationary object

Solution Approach 1:

The pressurizing chamber is segmented into two parts: one formed by the plunger and housing (for pressure generation) and another by the cylinder and cover member (for fuel storage and passage). This segmentation allows the high-pressure zone to be isolated from the housing walls, eliminating the need to increase housing size for rigidity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A cylinder is introduced as an intermediary component between the plunger and the housing. The cylinder receives the plunger and contains the pressurizing chamber, acting as a mediator that protects the housing from direct exposure to high fuel pressure, thereby preventing housing deformation without requiring size increase.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If the cover member is fixed to the housing with screws to form the pressurizing chamber, then the fuel pressure force is conducted to the housing, but the housing size must be increased to achieve sufficient rigidity

Engineering Contradiction:

Improvehousing rigidityVSAvoidhousing size

Core Design Contradiction:

StrengthVSVolume of stationary object

Solution Approach 1:

The pressurizing chamber is segmented into two parts: one formed by the plunger and housing (for pressure generation) and another by the cylinder and cover member (for fuel storage and passage). This segmentation allows the high-pressure zone to be isolated from the housing walls, eliminating the need to increase housing size for rigidity.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If the small diameter portion of the cylinder is not held by the housing, then the structure is simpler, but the small diameter portion may be deformed causing seizing of the plunger

Engineering Contradiction:

Improvestructural complexityVSAvoidplunger movement reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Instead of holding the small diameter portion of the cylinder horizontally (radially), the housing holds it vertically (axially) from below. This dimensional change in support direction prevents deformation and plunger seizing while maintaining structural simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Reliability

If the wall thickness of the small diameter portion of the cylinder is increased to limit deformation, then seizing is avoided, but the size of the cylinder is increased

Engineering Contradiction:

Improveplunger movement reliabilityVSAvoidcylinder size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Instead of holding the small diameter portion of the cylinder horizontally (radially), the housing holds it vertically (axially) from below. This dimensional change in support direction prevents deformation and plunger seizing while maintaining structural simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 design effectively limits the upward movement of the cylinder, reduces housing size and weight, and enhances manufacturing efficiency by distributing pressure forces uniformly, improving the pump's structural integrity and operational efficiency.

Implementation Method 1

The inner peripheral wall slidably guides the plunger

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

fuel is pressurized in a pressurizing chamber by a plunger, which is reciprocated by rotation of a camshaft

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS9945363B2High pressure pump with pressurizing chamber

Publication Date: 2018.04.17 DENSO CORP

AI summary

A cylinder is configured into a bottomed tubular form and includes an inner peripheral wall, an inner bottom wall, an outer peripheral wall and an intake hole and a discharge hole. The inner peripheral wall slidably guides the plunger. The intake hole and the discharge hole communicate between the inner peripheral wall and the outer peripheral wall. A pump housing includes a cylinder receiving hole that includes an inner peripheral wall, into which the cylinder is inserted. A pressurizing chamber is formed by the inner peripheral wall and the inner bottom wall of the cylinder and a distal end outer wall of the plunger.