Hydraulic Capsule for Engine Brake Actuation
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Solution Overview
Problem
Existing engine brake actuators experience impact loading and failure between the latch pin and seeger clip when pressurized during braking mode, which is a common issue in valvetrain assemblies of internal combustion engines.
Innovation Solution
The proposed solution involves a rocker assembly with an engine brake capsule assembly that includes a movable plunger, check ball valve, oil channel, and spool valve, which transitions between retracted and extended positions to engage or disengage the valve bridge, eliminating the need for a seeger clip and reducing impact loads by using hydraulic fluid pressure to actuate the plunger and control the oil channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional latch pin and seeger clip mechanism is used in engine brake actuators, then the structure is simple, but impact loading and failure occur during pressurization in braking mode
Solution Approach 1:
The patent replaces the traditional mechanical latch pin and seeger clip retention mechanism with a hydraulic retention mechanism. The capsule assembly uses hydraulic fluid pressure applied to a plunger to retain the valve bridge, eliminating the need for mechanical fasteners that are susceptible to impact loading and failure during engine braking operations.
Solution Approach 2:
The patent employs a hydraulic system where hydraulic fluid is introduced into the capsule assembly and applied to a plunger. The pressurized plunger engages with the valve bridge to provide retention force, replacing mechanical fastening methods with a hydraulic retention mechanism that better withstands impact loads during braking mode.
2Ease of operation
If hydraulic fluid is introduced into the capsule assembly, then the plunger is actuated to engage the valve bridge, but impact loading occurs during pressurization
Solution Approach 1:
The patent eliminates the mechanical latch pin and seeger clip system entirely, replacing it with a hydraulic plunger mechanism. The plunger is actuated by hydraulic fluid pressure to engage the valve bridge, providing a more robust solution that avoids the impact loading problems inherent in mechanical fastener systems during engine braking.
3Reliability
If a seeger clip is used to retain the latch pin, then the assembly is compact, but failure occurs during engine braking
Solution Approach 1:
The patent extracts and eliminates the seeger clip and latch pin components from the assembly, replacing them with a hydraulic plunger mechanism. This removal of problematic mechanical fasteners eliminates the failure mode that occurs during engine braking while the hydraulic system provides reliable retention of the valve bridge.
Solution Approach 2:
The patent substitutes the mechanical seeger clip and latch pin retention system with a hydraulic retention system. The plunger, actuated by hydraulic fluid pressure, provides the necessary retention force for the valve bridge without relying on mechanical fasteners that are prone to failure under impact loading during braking operations.
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 design enhances the reliability of engine brake actuators by reducing the risk of failure and eliminating the need for a seeger clip, thereby improving the durability and performance during engine braking operations.
Implementation Method 1
a check ball valve assembly disposed within the lower chamber configured to selectively enable a hydraulic fluid into the lower chamber to move the plunger from the retracted position to the extended position
Implementation Method 2
a spool valve configured to selectively block the oil channel
Implementation Method 3
an oil channel fluidly coupled to the lower chamber and configured to direct a flow of the hydraulic fluid out of the lower chamber during a transition from the extended position to the retracted position
Data Source
AI summary
A rocker arm assembly includes an engine brake capsule assembly. The engine brake capsule assembly is movable between a retracted position and an extended position to selectively engage a valve bridge to open a first exhaust valve. The engine brake capsule assembly includes an outer housing including a lower chamber and a plunger. The plunger extends out below the outer housing. The engine brake capsule assembly further includes a check ball valve assembly disposed within the lower chamber configured to selectively enable a hydraulic fluid into the lower chamber and an oil channel fluidly coupled to the lower chamber and configured to direct a flow of the hydraulic fluid out of the lower chamber. The engine brake capsule assembly further includes a spool valve configured to selectively block the oil channel.