Deactivating Rocker Arm Capsule With Lost Motion Spring
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Solution Overview
Problem
Existing rocker arms for cam-actuated valvetrains face challenges in switching functionalities due to size constraints, reliable actuation, and connection issues between actuators and rocker arms, particularly in achieving lightweight, fast-acting, and low actuation force requirements.
Innovation Solution
The development of deactivating rocker arms and capsules, including hydraulic and electromagnetic variants, which incorporate lost motion springs and latch mechanisms to enable flexible assembly and efficient actuation, allowing for drop-in installation of components and minimizing packaging space while balancing moments of inertia for reduced twisting and optimized valve actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rocker arms are used for cam-actuated valvetrains, then reliable actuation is achieved, but the size and packaging space requirements increase
Solution Approach 1:
The patent implements nesting by placing the capsule (containing plunger, latch set, and lost motion spring) inside the rocker arm structure. The capsule is received within a capsule bore of the rocker arm, with the plunger reciprocating within the capsule body. This nested arrangement allows the deactivation mechanism to be compactly integrated into the existing rocker arm volume, reducing overall packaging space while maintaining reliable actuation functionality.
2Volume of moving object
If rocker arms are made smaller to reduce packaging space, then packaging space is reduced, but reliable actuation and connections between actuators and rocker arms become challenging
Solution Approach 1:
The patent segments the rocker arm into distinct functional modules: the main rocker arm body, the capsule (containing plunger, latch set, and lost motion spring), and the actuator connection interface. This segmentation allows each component to be optimized independently for its specific function while maintaining compact overall dimensions. The capsule acts as a self-contained deactivation mechanism that can be precisely fitted within the rocker arm, ensuring reliable actuation without increasing packaging space.
3Weight of moving object
If lightweight rocker arms are designed to reduce weight, then weight is reduced, but actuation force requirements and structural integrity become challenging
Solution Approach 1:
The patent replaces traditional mechanical spring-based return mechanisms with a hydraulic or electromagnetic capsule system. The capsule uses fluid pressure (hydraulic) or electromagnetic fields to control the plunger and latch set, eliminating the need for heavy mechanical return springs. This substitution reduces the overall weight of the rocker arm assembly while providing controlled actuation forces through the capsule's pressure or electromagnetic actuation, rather than relying solely on mechanical leverage.
4Speed
If fast-acting valve actuation is implemented, then valve response speed is improved, but actuation force requirements and precision control become challenging
Solution Approach 1:
The patent employs a hydraulic capsule system where fluid pressure acts on the plunger to provide fast-acting valve actuation. The hydraulic fluid can be rapidly pressurized to move the plunger and release the latch set, achieving quick valve response. The incompressibility of hydraulic fluid ensures precise force transmission, allowing fast actuation without requiring excessive force. The lost motion spring within the capsule further assists by providing controlled mechanical energy storage and release for rapid valve opening.
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 solution enables lightweight, fast-acting, and low-force valve actuation with reduced packaging requirements, eliminating the need for return springs and allowing for flexible valve operation modes, including cylinder deactivation and dynamic control, while maintaining efficient actuation forces.
Implementation Method 1
A lost motion spring can be incorporated into the hydraulic capsule, or the lost motion spring can be installed in capsule bore where the hydraulic capsule is mounted
Implementation Method 2
The deactivating capsules can be hydraulic capsules or electromagnetic capsules
Implementation Method 3
The electromagnetic latch can comprise a solenoid-actuated pin and an actuatable plunger selectively latched and unlatched by the solenoid-actuated pin
Data Source
AI summary
A rocker arm including a cam side arm and a valve side arm is disclosed. The cam side arm can include a bearing surface, a cam-side pivot extension, and a plunger set seat. The valve side arm can include a rocker shaft bore configured to receive a rocker shaft, a valve-side pivot extension pivotally connected to the cam-side pivot extension, a capsule comprising a plunger set, and a capsule mount configured to receive the capsule. The capsule mount can include a lost motion spring.