Solenoid Valve Coil Current Threshold for Low-Energy Hold Open

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Solution Overview

Problem

Existing solenoid valves in hydrogen storage systems for vehicles consume unnecessary electrical energy due to continuous current flow to keep the valve open, and there is variability in the current required to maintain the open position due to technical tolerances.

Innovation Solution

A method and device to determine a lower current threshold for solenoid coils by actively energizing and de-energizing the coil based on detectable changes in current flow, using a variable current threshold to minimize energy consumption by pulsating the coil with a sawtooth or sinusoidal waveform.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous current flows through the solenoid coil to keep the solenoid valve open, then the valve remains reliably open during driving, but electrical energy is continuously consumed

Engineering Contradiction:
Improvevalve open position reliabilityVSAvoidelectrical energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by using pulsed current instead of continuous current to maintain the solenoid valve in the open position. The control unit sends periodic current pulses to the solenoid coil, which are sufficient to keep the valve open without requiring constant current flow. This reduces electrical energy consumption while maintaining the valve's open state during vehicle operation.

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If current threshold is set low to reduce energy consumption, then energy efficiency improves, but the solenoid valve may close due to technical tolerances and current variability

Engineering Contradiction:
Improveelectrical energy consumptionVSAvoidvalve open position stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements feedback by using a control unit that continuously monitors the current flowing through the solenoid coil and adjusts the current threshold dynamically. The control unit receives feedback about the actual current level and technical tolerances, then adapts the threshold to ensure the valve remains reliably open. This feedback mechanism allows the system to maintain low energy consumption while compensating for current variability and technical tolerances.

Inventive Principle:
Principle #23Feedback

3Reliability

If current threshold is set high to ensure valve remains open, then valve reliability improves, but energy consumption increases unnecessarily

Engineering Contradiction:
Improvevalve open position stabilityVSAvoidelectrical energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the current threshold adjustable and adaptive rather than fixed. The control unit dynamically determines the appropriate current threshold based on actual operating conditions, technical tolerances, and measured current levels. This dynamic approach allows the system to use the minimum necessary current to keep the valve reliably open, avoiding unnecessary energy consumption while maintaining reliability.

Inventive Principle:
Principle #15Dynamics

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 approach allows for efficient and reliable determination of the minimum current required to keep solenoid valves open, reducing overall energy consumption and adapting to changes in valve properties over time.

Implementation Method 1

a solenoid coil (2) of a solenoid valve... when an electric current at the level of the current band flows through the solenoid coil (2), an armature of the solenoid valve movable by the solenoid coil is held in a fully open position

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

If no current flows through the solenoid coil of the valve, the solenoid valve closes automatically, for example, due to spring force. This behavior is necessary for safety reasons, but has the disadvantage that current must continuously flow through the solenoid coil during driving to keep the solenoid valve open.

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4487353B1Method for determining a lower current threshold of a strip conductor of a solenoid coil of a solenoid valve for a valve unit which is fluidically connected to a pressurized fluid reservoir, device, and vehicle
Publication Date: 2026.03.11 ROBERT BOSCH GMBH
  • EP4487353B1 patent drawingFigure 1
  • EP4487353B1 patent drawingFigure 2~3
  • EP4487353B1 patent drawingFigure 4(1)~4(3)

AI summary

The invention relates to a method for determining the lower current threshold (US) of a strip conductor (B) of a solenoid coil (2) of a solenoid valve, said method having the steps of: - actively energizing the solenoid coil (2) of the solenoid valve, wherein the process of actively energizing the solenoid coil (2) of the solenoid valve is deactivated upon detecting an electric current flowing through the solenoid coil (2) at the level of an upper current threshold (OS) of the strip conductor (B), and actively energizing the solenoid coil (2) of the solenoid valve again using the electric power source upon detecting an electric current flowing through the solenoid coil (2) at the level of an ascertainable modifiable current threshold, - changing (10) the level of the ascertainable modifiable current threshold, - continuously measuring (20) a measurement signal in order to detect a change in the state of the armature of the solenoid valve between the at least one movement state and the rest state of the armature, and - determining (40) the lower current threshold (US) of the strip conductor (B) on the basis of the ascertainable modifiable current threshold when the change in state of the armature of the solenoid valve is detected (30) on the basis of the change of the ascertainable modifiable current threshold.