Solenoid Valve Braking Current for Engine Valve Timing

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Solution Overview

Problem

Solenoid valves in internal-combustion engine systems with multi-lift actuation modes face limitations due to the normally open type design, where the pusher element takes time to return to its resting position after de-energization, necessitating a minimum time gap between successive activations, restricting the ability to control second subcycles of valve opening without waiting for this return.

Innovation Solution

Applying a braking current during the upward movement of the movable core and pusher element after deactivation of the solenoid valve, which reduces the time required for the pusher element to return to its resting position and contact with the valve element, allowing for reduced time between successive activations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a normally open solenoid valve with a separate pusher element is used, then the valve element can be driven to the closed condition reliably, but the pusher element takes time to return to its resting position after de-energization, setting a minimum time limit between successive energizations

Engineering Contradiction:

Improvevalve closing reliabilityVSAvoidtime between successive energizations

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

A return spring is pre-loaded to assist the pusher element's return movement. The spring is compressed during valve closing and automatically expands to propel the pusher element back to its initial position, reducing the waiting time before the next energization cycle can begin.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The solenoid valve is energized in periodic pulses rather than continuous operation. By timing the energization cycles to coincide with the pusher element's return movement assisted by the return spring, the system achieves multiple valve actuations within the constraints of the mechanical return time.

Inventive Principle:

Principle #19Periodic action

2Reliability

If the pusher element is rigidly connected to the movable core, then the valve element can be driven to the closed condition, but the pusher element detaches from the valve element during return stroke, requiring additional time to re-contact

Engineering Contradiction:

Improvevalve closing force transmissionVSAvoidpusher element structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pusher element is divided into two separate components: a movable core that receives electromagnetic force and a pusher rod that transmits force to the valve element. This segmentation allows the movable core to return independently while the pusher rod maintains contact with the valve element through a retaining structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A retaining structure acts as an intermediary between the pusher element and the valve element, ensuring continuous contact during the return stroke. This intermediary component prevents detachment while allowing the necessary mechanical movement for valve actuation.

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 approach reduces the minimum time between solenoid valve activations, enabling more frequent cycles of valve opening and closing within a traditional cycle, thereby optimizing engine valve control without compromising solenoid valve operation or longevity.

Implementation Method 1

a solenoid (111) designed to generate, when energized, a magnetic field driving the movable core (112) with associated pusher element (113) in a first direction towards the valve element (105)

Methodology Applied

Scientific EffectMagnetic field generation: Electromagnet

Implementation Method 2

supplying a braking current to the solenoid (111) during a movement of the movable core (112) and associated pusher element (113) in a second direction, opposite to the first direction, towards an initial position

Methodology Applied

Scientific EffectMagnetic braking: Electromagnet

Data Source

PatentUS7878480B2System and method for controlling a solenoid valve, particularly for a system for variable actuation of the valves of an internal combustion engine according to a multi-lift mode

Publication Date: 2011.02.01 CENTRO RICERCHE FIAT SCPA

AI summary

A solenoid valve, particularly of the type to be used for controlling a hydraulic system for variable actuation of the valves of an internal-combustion engine, has a valve element co-operating with a valve seat and a pusher element, separate from the valve element, which is pushed against the valve element by the movable core of the solenoid valve when the solenoid of the solenoid valve is energized in order to bring the valve element into contact with the valve seat. After de-energization of the solenoid, the time necessary for bringing back the pusher element into the resting condition in contact with the valve element is reduced thanks to the application of a braking current to the solenoid of the solenoid valve during the stage in which the movable core and the pusher element associated thereto displace in the direction opposite to the direction of the movement generated by the magnetic field of the solenoid, following upon de-energization of the solenoid valve.