Safety Actuator Assembly for Reciprocating Engine Overhead Valves

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Solution Overview

Problem

Reciprocating internal combustion piston engines with overhead valves are prone to malfunction, leading to increased pressure and temperature levels in the combustion cylinder, which can cause engine damage, necessitating emergency shutdowns.

Innovation Solution

A safety actuator assembly that can independently actuate the overhead valve into a safety position, maintaining sufficient clearance and fluid communication to prevent damage, allowing the engine to operate in safety mode without shutting down.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fluid operated piston is used to control overhead valve, then more precise control is obtained, but malfunction risk increases

Engineering Contradiction:
Improveoverhead valve control precisionVSAvoidoverhead valve operation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The overhead valve control system is segmented into two independent parts: a primary fluid operated piston for normal precise control, and a secondary safety actuator with mechanical linkage for emergency operation. This segmentation allows the system to maintain precision while adding a fail-safe mechanical backup that operates independently of the fluid control system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The safety actuator is designed to activate automatically when the fluid operated piston malfunctions. The mechanical linkage and spring-loaded components are pre-positioned to provide immediate backup control, cushioning against the harmful effects of fluid system failure before they can cause engine damage.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If overhead valve remains closed due to malfunction, then fluid communication is blocked, but pressure and temperature levels increase causing engine damage

Engineering Contradiction:
Improveoverhead valve positioning reliabilityVSAvoidpressure and temperature increase
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The safety actuator applies preliminary anti-action by automatically opening the overhead valve when malfunction is detected, counteracting the harmful effect of the valve remaining closed. The mechanical linkage and spring mechanism are designed to overcome the valve spring force and open the valve, preventing pressure and temperature buildup in the combustion chamber.

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If safety actuator is added to overhead valve system, then safety mode operation is enabled, but device complexity increases

Engineering Contradiction:
Improveengine safety operationVSAvoidoverhead valve actuation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The safety actuator is merged with the existing overhead valve actuation mechanism. The mechanical linkage connects the safety actuator directly to the valve stem, combining the emergency actuation function with the existing valve train. This integration minimizes additional components while providing reliable safety functionality.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables the engine to continue operating with malfunctioning overhead valves in safety mode, preventing further damage and maintaining engine operation using normally functioning cylinders.

Implementation Method 1

a safety piston movable between a first safety position and a second safety position. The safety piston is configured to enable movement from the first safety position to the second safety position

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP3743602B1A safety actuator assembly and a reciprocating internal combustion piston engine having such a safety actuator assembly
Publication Date: 2021.12.01 WARTSILA FINLAND OY
  • EP3743602B1 patent drawingFigure 1
  • EP3743602B1 patent drawingFigure 2

AI summary

The disclosure relates to a safety actuator (1) for operating a respective overhead valve (2) of a reciprocating internal combustion piston engine, comprising an operating configuration for operating the respective overhead valve (2) between a closed position and an open position during normal operating mode, and a safety configuration for operating the respective overhead valve between a closed position and a safety position during a safety operating mode. A safety actuator assembly comprising a operation control valve (6) for controlling the operating configuration, and a safety control valve (7) for controlling the safety configuration is also concerned. In addition, a reciprocating internal combustion engine having such a safety actuator assembly is also discussed.