Compression Brake Tappet Hydraulic Actuation
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Solution Overview
Problem
Compression braking in light-duty internal combustion engines faces challenges due to high component costs and limited engine space, necessitating innovative solutions that do not require significant changes to existing engine platforms.
Innovation Solution
A compression braking system that incorporates a brake tappet and a hydraulic system to selectively activate and deactivate the brake tappet, utilizing a camshaft with a brake lobe to convert the engine into a compressor during the compression stroke, allowing power to be dissipated without the need for extensive modifications to the engine's major components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compression brake components are added to light-duty engines, then braking capability is improved, but component cost increases
Solution Approach 1:
The brake tappet is integrated into the existing valve train system, merging the braking function with the camshaft and valve mechanism. This consolidation eliminates separate braking components and reduces overall system cost while maintaining braking capability.
Solution Approach 2:
The camshaft serves dual functions: actuating the intake and exhaust valves during normal operation, and actuating the brake tappet to enable compression braking. This multi-functionality reduces the need for dedicated braking components, lowering component costs.
2Reliability
If compression brake system is added to light-duty engines, then braking capability is improved, but engine space requirements increase
Solution Approach 1:
The brake tappet is nested within the existing valve train assembly, utilizing the space already allocated for valve actuation components. The brake mechanism is housed within the same structural envelope as the camshaft and valve train, preventing engine space expansion.
Solution Approach 2:
By merging the braking system with the existing valve train and camshaft mechanism, the patent eliminates the need for separate braking component housing and mounting space, thereby maintaining compact engine layout.
3Reliability
If compression brake system is added to light-duty engines, then braking capability is improved, but device complexity increases
Solution Approach 1:
The camshaft is designed to perform multiple functions: actuating intake valves, exhaust valves, and the brake tappet. This multi-functionality reduces the number of separate actuators and control mechanisms needed, thereby simplifying the overall system despite adding braking capability.
Solution Approach 2:
The brake tappet utilizes the existing camshaft rotation and valve train motion to automatically enable and disable compression braking. The system leverages the engine's own operational cycles to control braking without requiring external actuators or complex control systems.
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 efficient compression braking in light-duty engines without significant changes to existing platforms, offering a cost-effective and space-efficient solution that can also be applied to heavy-duty and mid-range engines, enhancing braking capabilities.
Implementation Method 1
A compression braking system for an internal combustion engine includes a brake tappet configured to link at least one exhaust valve to an exhaust cam. The exhaust cam includes a brake bump portion and an exhaust lobe. The brake tappet includes a housing extending along a longitudinal axis and a lash assembly in an interior of the housing. The lash assembly is longitudinally movable relative to the housing. The compression braking system includes first and second locking pins in the housing movable relative to the lash assembly to selectively fix and release the lash assembly relative to the housing. A change in pressure of a working fluid moves the first and second locking pins to selectively fix and release the lash assembly relative to the housing.
Data Source
AI summary
An engine compression braking system includes a brake tappet linking an exhaust cam to at least one exhaust valve of an engine cylinder. The brake tappet is connected with a working fluid that selectively activates and deactivates a compression braking mode of operation by selectively engaging and releasing a lash assembly of the brake tappet relative to a housing of the brake tappet.