Hydraulic Actuator for Gas Exchange Valve Timing Control

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Solution Overview

Problem

Large internal combustion engines face challenges in achieving flexible and reliable gas exchange valve actuation, as conventional cam-driven mechanisms are inflexible and difficult to adjust, while electro-hydraulic systems offer flexibility at the cost of reduced reliability.

Innovation Solution

A hydraulic actuator system that includes a pressurizing chamber, drive piston, hydraulic valve, and adjustable throttles, minimizing electrical components and combining the reliability of mechanical systems with the flexibility of electro-hydraulic systems, allowing simultaneous control of gas exchange valves with reduced energy consumption and improved valve timing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cam-driven valve opening mechanisms are used, then reliability is maintained, but flexibility and ease of adjusting valve timing are reduced

Engineering Contradiction:
ImprovereliabilityVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs a hydraulic actuator system where pressurized hydraulic fluid is directed to a drive piston to open the gas exchange valve. This hydraulic mechanism replaces the traditional cam-driven mechanical system, maintaining reliability through proven hydraulic technology while enabling flexible and precise control of valve timing through adjustable throttles and controllable fluid pressure.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Adaptability or versatility

If electro-hydraulic systems are used for variable valve timing, then flexibility is improved, but reliability is reduced

Engineering Contradiction:
ImproveflexibilityVSAvoidreliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent removes electrical components from the valve actuating mechanism, extracting the unreliable electrical elements while retaining the flexible control capabilities. The system uses purely mechanical and hydraulic components - the drive piston, hydraulic fluid, and adjustable throttles - eliminating the need for motors, sensors, and control electronics, thus improving reliability while maintaining flexibility through mechanical adjustment possibilities.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electro-hydraulic system with a purely mechanical-hydraulic system. Instead of using electrical motors and electronic controls to vary valve timing, the invention uses mechanically adjustable throttles that control hydraulic fluid flow to the drive piston, substituting electrical control mechanisms with mechanical adjustment means to enhance reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If hydraulic actuator is used instead of cam-driven mechanism, then flexibility in valve timing is improved, but number of electrical components increases

Engineering Contradiction:
ImproveflexibilityVSAvoidnumber of electrical components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent substitutes electrical control systems with a mechanical-hydraulic control system. The adjustable throttles, drive piston, and hydraulic fluid work together as a purely mechanical-hydraulic system, eliminating motors, electronic sensors, and control circuits. This substitution maintains flexibility in valve timing control while dramatically reducing the number of electrical components in the system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If drive piston stroke is limited to control valve lift, then excessive valve lifts are prevented, but control range is restricted

Engineering Contradiction:
Improvecontrol precisionVSAvoidcontrol range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs adjustable throttles that can modify the flow characteristics of hydraulic fluid to the drive piston. By changing the throttle opening, the system controls the rate and amount of hydraulic fluid reaching the piston, thereby precisely controlling valve opening speed and timing. The stroke limitation is compensated by adjusting fluid flow parameters, maintaining control precision while providing adequate control range for various operating conditions.

Inventive Principle:
Principle #35Parameter changes

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 hydraulic actuator system enhances reliability and flexibility in gas exchange valve operation, preventing excessive valve lifts and allowing for adjustable opening and closing speeds, while reducing the number of electrical components and energy consumption.

Implementation Method 1

a pressurizing chamber for pressurizing hydraulic fluid, a drive piston that is arranged in the pressurizing chamber and which drive piston divides the pressurizing chamber into at least one input portion and at least one output portion

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

a hydraulic valve having a first position, in which position flow from the inlet duct to the input portion of the pressurizing chamber is allowed and flow from the input portion to the outlet duct is prevented, and a second position, in which position flow from the inlet duct to the input portion of the pressurizing chamber is prevented and flow from the input portion to the outlet duct is allowed

Methodology Applied
Scientific EffectHydraulic flow control: Hydraulic Press

Data Source

PatentEP2834480B1Hydraulic actuator and gas exchange valve arrangement
Publication Date: 2016.02.24 WARTSILA FINLAND OY
  • EP2834480B1 patent drawingFigure 1~2
  • EP2834480B1 patent drawingFigure 3
  • EP2834480B1 patent drawingFigure 4

AI summary

The hydraulic actuator (35) for opening a gas exchange valve of an internal combustion engine comprises a drive piston (7) that is arranged in a pressurizing chamber (9) for pressurizing hydraulic fluid. A hydraulic valve (10) having two positions is used for operating the hydraulic actuator (35). The invention also concerns a gas exchange valve arrangement.