Integrated Spline-Bushing Valve Bridge for Lost-Motion Engine Braking

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Solution Overview

Problem

Existing internal combustion engines face challenges in efficiently deactivating valves for cylinder deactivation and implementing engine braking functions, as rocker arms often transfer motion regardless of valve activation needs.

Innovation Solution

A rocker arm assembly with switchable castellation assemblies and a valve bridge assembly that allows selective engagement and deactivation of valves, incorporating a rotatable spline bushing to switch between locked and unlocked positions for lost motion, enabling independent control of valve motion for engine braking and cylinder deactivation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rocker arms continuously transfer motion to valves, then valve actuation is maintained, but energy consumption increases and valve deactivation is impossible

Engineering Contradiction:

Improvevalve actuation efficiencyVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The rocker arm assembly incorporates switchable castellation mechanisms that dynamically change the motion transfer state between engaged and disengaged positions, allowing the system to adapt between active valve actuation and deactivated states based on operating conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The rocker arm is divided into separate functional segments including first and second castellation assemblies that can independently control motion transfer to different valves, enabling selective deactivation of individual valves or cylinder groups

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If rocker arms transfer motion to all valves, then complete valve actuation is achieved, but selective valve deactivation for cylinder deactivation cannot be implemented

Engineering Contradiction:

Improvevalve control flexibilityVSAvoidrocker arm mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rocker arm assembly is segmented into multiple independent castellation mechanisms (first and second assemblies) that can be selectively engaged or disengaged to control individual valves or valve groups, enabling flexible cylinder deactivation strategies

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rocker arm assembly serves multiple functions by incorporating both engine braking capability through the first castellation assembly and cylinder deactivation capability through the second castellation assembly, allowing a single component to handle diverse operational requirements

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If lost motion is implemented for engine braking, then engine brake function is achieved, but valve motion control precision is reduced

Engineering Contradiction:

Improveengine brake functionVSAvoidvalve motion control precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The spline bushing mechanism dynamically transitions between locked and unlocked states to provide lost motion during engine braking while maintaining precise motion control during normal operation, adapting the level of precision based on operational mode

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12448905B2Valve bridge with integrated spline bushing for lost motion and engine brake

Publication Date: 2025.10.21 EATON INTELLIGENT POWER LTD

AI summary

A rocker arm assembly for an engine including a main body rotatable about a shaft. The main body has a roller end and a valve end. A first switchable castellation assembly is disposed in the valve end. The first switchable castellation assembly has a distal end configured to selectively move a first valve. A second switchable castellation assembly is disposed in the valve end. The second switchable castellation assembly has a distal end configured to engage a valve bridge assembly. The valve bridge assembly is configured for engaging and actuating a second valve.