Gas Valve Nozzle Needle Force Reduction via Segmented Sealing

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Solution Overview

Problem

Existing gas valves are unsuitable for high gas pressures above 30 bar due to the large forces required to move the nozzle needle, which cannot be easily overcome by conventional electrical actuators or electromagnets, leading to increased space and energy requirements and costs.

Innovation Solution

A valve design featuring a piston-shaped nozzle needle with two axially offset sealing seats and an elastic metal bellows that separates high and low pressure areas, allowing for pressure equalization and reducing the forces on the nozzle needle, enabling the use of existing actuators without additional components or increased size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If conventional gas valves are used for high gas pressures (300-500 bar), then the forces on the nozzle needle become too large to be overcome by existing actuators, requiring considerably larger actuators which increase space requirements, cost, and energy consumption

Engineering Contradiction:
Improvegas pressureVSAvoidforce on nozzle needle
Core Design Contradiction:
Stress or pressureVSForce

Solution Approach 1:

The sealing function is segmented into two separate sealing seats: a first sealing seat on the nozzle needle and a second sealing seat on a valve element. This segmentation allows the high-pressure region to be separated from the low-pressure region, so that the nozzle needle only needs to overcome the pressure difference across the first sealing seat area, rather than the full high pressure, significantly reducing the force required on the nozzle needle

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A valve element supported by an elastic element (metal bellows) is introduced as an intermediary component. This valve element closes the second sealing seat in the low-pressure region and is responsible for balancing the pressure forces. The elastic element mediates between the high-pressure and low-pressure regions, allowing pressure equalization while maintaining the sealing function, thereby reducing the net force on the nozzle needle

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If larger actuators are used to overcome high forces at high gas pressures, then the space requirements within the gas valve increase

Engineering Contradiction:
Improveactuator forceVSAvoidvalve volume
Core Design Contradiction:
ForceVSVolume of stationary object

Solution Approach 1:

By segmenting the sealing function into two separate sealing seats with different pressure regions, the system reduces the force requirement on the nozzle needle actuator. This allows the use of smaller, existing actuators rather than requiring larger actuators that would increase the valve volume

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure chamber and elastic element create a self-balancing mechanism where the high-pressure gas itself helps balance the forces on the valve element through the second sealing seat. This self-service pressure balancing reduces the burden on the external actuator, allowing compact valve design with existing actuators

Inventive Principle:
Principle #25Self-service

3Force

If larger actuators are used to overcome high forces at high gas pressures, then the energy consumption of the system increases

Engineering Contradiction:
Improveactuator forceVSAvoidenergy consumption
Core Design Contradiction:
ForceVSUse of energy by moving object

Solution Approach 1:

Segmenting the sealing into two pressure regions reduces the force that the actuator must overcome, directly reducing the energy consumption of the actuator. The first sealing seat handles the high-pressure sealing while the second sealing seat in the low-pressure region requires minimal force to operate

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The elastic element and valve element act as intermediaries that utilize the high-pressure gas to balance forces passively. This force balancing mechanism reduces the active work required by the actuator, thereby reducing energy consumption while maintaining control capability

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

This design allows for efficient operation at high gas pressures without the need for larger actuators, reducing energy consumption and space requirements, while maintaining effective control over the flow of gaseous fuel.

Implementation Method 1

a valve element, which is axially offset from the first sealing seat with respect to the longitudinal axis of the nozzle needle and is supported by an elastic element that separates the high-pressure area from the low-pressure area

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The movement of the closing element within the gas-filled pressure chamber is usually controlled by a piezoelectric actuator or an electromagnet

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

The movement of the closing element within the gas-filled pressure chamber is usually controlled by a piezoelectric actuator or an electromagnet

Methodology Applied
Scientific EffectElectromagnetism: Electromagnet

Data Source

PatentEP3478957B1Valve for injecting gaseous fuel
Publication Date: 2020.05.13 ROBERT BOSCH GMBH
  • EP3478957B1 patent drawingFigure 1a
  • EP3478957B1 patent drawingFigure 1b
  • EP3478957B1 patent drawingFigure 2a

AI summary

The invention relates to a valve (1) for injecting gaseous fuel comprising a valve housing (2) in which a pressure chamber (24) that can be filled with gaseous fuel is formed. A longitudinally moveable piston-type nozzle needle (4) is arranged in this pressure chamber (24), on which a first seal seat (19, 19', 19", 19"') is formed, with which the nozzle needle (4) cooperates with a shoulder (9, 9', 9", 9"') formed on the valve housing (2) for opening and closing a flow cross-section of gaseous fuel. A high-pressure region (16) and a low-pressure region (17) are also formed in the pressure chamber (24). In addition, a second seal seat (18, 18', 18", 18"') is formed on a valve element (5), which is arranged axially offset to the first seal seat (19, 19', 19", 19"') relative to a longitudinal axis (10) of the valve (1). The valve element (5) is supported on an elastic element (7), wherein this elastic element (7) separates the high-pressure region (16) from the low-pressure region (17).