Hydraulic Engine Brake for Type II Valvetrains
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Solution Overview
Problem
Existing engine brake systems for internal combustion engines with Type II valvetrains are not effectively suited for various valvetrain configurations, limiting their application and efficiency in kinetic energy absorption and vehicle braking.
Innovation Solution
A hydraulic engine brake arrangement is integrated into the Type II valvetrain system, featuring a brake housing with a hydraulic circuit, a follower piston, and a brake piston that interacts with a finger follower to manage compression release and valve operation, allowing for selective engine braking through solenoid valve control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional engine brake system is used, then kinetic energy absorption is achieved, but the system is not suitable for Type II valvetrain configurations
Solution Approach 1:
A finger follower component serves as an intermediary element that bridges the hydraulic brake mechanism and the Type II valvetrain components. The finger follower translates hydraulic piston movement into valve actuation while maintaining compatibility with the existing valvetrain geometry, enabling effective engine braking without requiring modification to the valvetrain architecture.
Solution Approach 2:
The brake rod and finger follower assembly is designed to perform multiple functions: it actuates the valve for compression release during engine braking, maintains proper valve clearance through lash adjustment, and interfaces with both the hydraulic system and the camshaft-driven valvetrain. This multi-functionality enables a single mechanism to serve both braking and valvetrain operation requirements.
2Loss of energy
If compression release engine braking is implemented, then kinetic energy absorption is enhanced, but the device complexity increases
Solution Approach 1:
The engine brake system merges the hydraulic actuation mechanism with the existing Type II valvetrain components. The follower piston, brake rod, and finger follower are integrated into the valvetrain assembly, sharing common mounting points and mechanical pathways. This consolidation reduces overall system complexity compared to adding a separate brake mechanism.
Solution Approach 2:
The system uses hydraulic pressure from the engine's oil pump to actuate the follower piston, which in turn drives the brake rod and finger follower assembly. This hydraulic actuation eliminates the need for separate mechanical linkages, springs, or actuators, simplifying the overall mechanism while enabling effective compression release braking.
3Productivity
If a hydraulic engine brake arrangement is added, then braking efficiency is improved, but the device complexity increases
Solution Approach 1:
The hydraulic engine brake system utilizes the engine's own oil pump and existing hydraulic circuitry to provide actuation pressure, eliminating the need for a separate hydraulic pump or external fluid supply. The system is self-contained, using resources already present in the engine to achieve improved braking efficiency without proportionally increasing complexity.
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 efficient hydraulically-actuated compression release engine braking in Type II valvetrain engines, enhancing kinetic energy absorption and reducing reliance on external braking systems, while maintaining conventional lash adjustment capabilities.
Implementation Method 1
The follower piston is configured to move between an extended position in which follower piston follows a rotating brake cam lobe and a retracted position in which the follower piston does not follow the rotating brake cam lobe
Implementation Method 2
a brake piston disposed in the brake piston chamber, the brake piston being in pressure responsive relation with the follower piston
Implementation Method 3
the brake rod moves the second end of the finger follower to lift the cylinder valve and release compression from the engine cylinder
Implementation Method 4
the finger follower is configured to pivot from the first end about a pivot as the finger follower follows a valve cam lobe to effect lifting and seating of a cylinder valve of an engine cylinder
Data Source
AI summary
A Type II valvetrain and engine brake arrangement includes a hydraulic brake housing mountable to a valve block of the engine. A brake piston is coupled to a brake rod and a brake cam lobe and is movable between an activated position and a non-activated position. A finger follower is disposed relative to the brake housing so that the brake rod engages the finger follower at least when the brake piston is in the activated position. When the brake piston is in a non-activated position, the finger follower is configured to pivot about a pivot as the finger follower follows a valve cam lobe to effect lifting and seating of a cylinder valve of an engine cylinder. When the brake piston is in the activated position, the finger follower, at least in part, pivots from about the pivot and the brake rod engages an end of the finger follower to lift the cylinder valve and release compression from the engine cylinder.