Fuel Pump Maximum-Pressure Valve Spherical Shutter Design

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Solution Overview

Problem

Current fuel pumps in direct-injection systems experience delayed response of the maximum-pressure valve when fuel pressure in the common rail slightly exceeds the set maximum value, leading to potential pressure increases beyond design limits, necessitating oversized components to prevent damage, which increases costs and weight without functional advantage.

Innovation Solution

The fuel pump incorporates a maximum-pressure valve with an annular groove and valve body design that enhances the hydraulic dynamic thrust to ensure rapid opening when pressure exceeds the set value, preventing excessive pressure increases by using an electromagnetic actuator and calibrated spring to control the intake and delivery valves, and a calibrated plate to maintain constant thrust during valve opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a conventional maximum-pressure valve with spherical shutter and valve seat is used, then the valve structure is simple, but the response speed is slow when pressure slightly exceeds the set maximum value

Engineering Contradiction:
Improveresponse speed of maximum-pressure valveVSAvoidvalve structure complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent applies spheroidality by using a spherical shutter that rotates within a spherical cavity. The spherical geometry allows for smooth rotational motion and optimized hydraulic force distribution, enabling faster response when pressure exceeds the set maximum value. The curved surfaces improve fluid dynamics and reduce resistance during valve opening.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent utilizes hydraulic principles by designing the spherical cavity and shutter interaction to amplify hydraulic dynamic thrust. The geometry of the spherical cavity works with fuel pressure to create sufficient force for rapid shutter rotation, eliminating the need for complex mechanical actuation systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If components are oversized to withstand pressure increases beyond design limits, then system reliability improves, but cost and weight increase

Engineering Contradiction:
Improvesystem reliability under pressure variationsVSAvoidcomponent weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The maximum-pressure valve operates autonomously to maintain pressure within design limits. When pressure exceeds the set maximum value, the valve automatically opens to relieve excess pressure, preventing the need for oversized components. This self-regulating mechanism ensures system reliability while allowing components to be sized for normal operating conditions only.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If a conventional maximum-pressure valve is used, then manufacturing cost is low, but pressure control precision deteriorates due to delayed response

Engineering Contradiction:
Improvepressure control precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The spherical geometry of the shutter and cavity provides precise pressure control through optimized hydraulic force distribution. The curved surfaces enable accurate response to pressure changes while maintaining manufacturability through standard machining processes for spherical components.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 ensures the maximum fuel pressure in the common rail remains within limits, even during slight pressure increases, avoiding unnecessary component oversizing and reducing manufacturing costs while maintaining system efficiency and reliability.

Implementation Method 1

a calibrated spring pushes the shutter towards a fluid-tight engagement position with the valve seat. The elastic force of the spring is calibrated so that the shutter is separated from the valve seat only when the pressure difference across the maximum-pressure valve is higher than the threshold value set in the design phase

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

the maximum-pressure valve with an annular groove and valve body design that enhances the hydraulic dynamic thrust to ensure rapid opening when pressure exceeds the set value

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Data Source

PatentEP3267029B1Fuel pump with an improved maximum-pressure valve for a direct-injection system
Publication Date: 2019.03.06 FAB ITAL MAGNETI MARELLI SPA
  • EP3267029B1 patent drawingFigure 1
  • EP3267029B1 patent drawingFigure 2
  • EP3267029B1 patent drawingFigure 3

AI summary

Fuel pump (1) for a direct-injection system and having: a pumping chamber (14); a piston (15); an intake channel (17) regulated by an intake valve (18); a delivery channel (22) regulated by a delivery valve (23); and a drain channel (32) that originates in the delivery channel (22) and is regulated by a maximum-pressure valve (33) having: a shutter (34), a valve body (36) provided with a valve seat (35), a calibrated spring (38) for pushing the shutter (34) against the valve seat (35), and a plate (39) that is arranged in contact with the shutter (34) on the opposite side of the valve seat (35); the plate (39) of the maximum-pressure valve (33) has a first annular groove (42), which is arranged around the shutter (34); and the valve body (36) of the maximum-pressure valve (33) has a second annular groove (43), which is arranged around the shutter (34) and at least partially faces the first annular groove (42) of the plate (39).