Direct-Acting Solenoid Variable Trigger Timing for Rocker Arm Switching

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Solution Overview

Problem

Existing solenoid systems in internal combustion engines face challenges in synchronizing switching modes with engine speed, leading to inconsistent valve actuation timing and mechanical resistance issues, particularly when fitting electrification equipment into compact engine compartments.

Innovation Solution

A direct-acting, overhead solenoid assembly with a calibratable actuation lever and compliance spring arrangement, allowing for variable timing of solenoid triggering based on engine speed, temperature, and voltage, which minimizes mechanical resistance and adapts to different valve actuation techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a constant trigger timing is used for the solenoid, then the control system is simple, but the valve actuation timing becomes inconsistent at different engine speeds

Engineering Contradiction:

Improvecontrol system complexityVSAvoidvalve actuation timing consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements variable trigger timing that dynamically adjusts the solenoid activation point based on engine speed. The ECU receives engine speed signals and calculates appropriate trigger timings to compensate for solenoid response time, ensuring consistent valve actuation timing across different operating conditions.

Inventive Principle:

Principle #15Dynamics

2Weight of moving object

If the solenoid mass is reduced, then the solenoid responds faster and fits better in engine compartment, but the solenoid force may be insufficient

Engineering Contradiction:

Improvesolenoid massVSAvoidsolenoid actuation force

Core Design Contradiction:

Weight of moving objectVSForce

Solution Approach 1:

The patent introduces a lever mechanism as an intermediary between the solenoid and the rocker arm latch. The lever provides mechanical advantage, allowing a smaller solenoid with less direct force to effectively actuate the latch. The lever pivots about a point and translates the solenoid's linear motion into rotational motion that moves the latch pin.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameters by triggering the solenoid during the lift portion of the cam cycle rather than on the base circle. This timing change exploits the mechanical conditions during valve lift when the rocker arm geometry provides favorable leverage, reducing the force required from the solenoid.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If the solenoid is triggered on the base circle, then the switching occurs at a fixed point in the cycle, but the mechanical resistance at the solenoid increases

Engineering Contradiction:

Improveswitching timing precisionVSAvoidmechanical resistance

Core Design Contradiction:

Loss of timeVSForce

Solution Approach 1:

The patent triggers the solenoid in advance during the lift portion of the cam cycle, before the rocker arm reaches the base circle position. This preliminary action allows the solenoid to complete its actuation while favorable mechanical conditions exist, and the switching effect takes place as the cam transitions to the base circle, achieving both early triggering benefits and reduced mechanical resistance.

Inventive Principle:

Principle #10Preliminary action

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

The solution enables precise and efficient valve actuation timing, reducing solenoid mass and mechanical resistance, while ensuring seamless integration into engine compartments, enhancing engine performance and reliability.

Implementation Method 1

A solenoid assembly is direct-acting and overhead and is calibratable with respect to the rocker arm

Methodology Applied

Scientific EffectSolenoid: Solenoid

Implementation Method 2

Alternative compliance spring arrangements, alternative actuator assemblies, and various latches and rocker arms are compatible with the timing technique

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS11982211B2Direct-acting solenoid having variable triggering timing for electro-mechanical valvetrain and actuation levers for switching rocker arms

Publication Date: 2024.05.14 EATON INTELLIGENT POWER LTD

AI summary

Systems, methods, and control systems for a switching rocker arm assembly are disclosed. A switching rocker arm (10) engages a valve (29), the switching rocker arm (10) is movable by contact with a cam (60) having a lift portion (59) and a base circle (58). The switching rocker arm (10) comprises an inner arm (20), an outer arm (12) pivotably secured to the inner arm (20) and having a latch bore, and a latch pin (28) selectively movable between a first position where the latch pin (28) does not contact the inner arm (20), and a second position wherein the latch pin (28) contacts the inner arm (20). A solenoid assembly (500) is energized while the rocker arm is in contact with the lift portion (59) of the cam. The solenoid assembly is direct-acting and overhead and is calibratable with respect to the rocker arm.