Rocker Arm Rotation-Locking Mechanism for Fast Engine Start-Up
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Solution Overview
Problem
Hydraulic systems in valvetrains face challenges such as delayed start-up due to oil pump pressure issues, large fluid compartments leading to supply difficulties and leakage, and the need for bulky sumps and long spool-up times.
Innovation Solution
A rocker arm assembly with a rotation-locking mechanism that includes a rocker shaft with an enclosed oil path and a locking pin or pressure pin that slides between locked and unlocked positions, allowing for variable valve actuation and reducing the need for bulky components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If large fluid compartments are used in rocker arms, then variable valve actuation is enabled, but supply difficulties arise and spool-up time increases
Solution Approach 1:
The patent extracts the hydraulic control function from the traditional large fluid compartment design and relocates it to a dedicated hydraulic control mechanism with a smaller fluid compartment. This separation allows the variable valve actuation function to be achieved without requiring large fluid volumes, thereby reducing spool-up time while maintaining adaptability.
Solution Approach 2:
The patent introduces a hydraulic control mechanism as an intermediary between the oil pump and the rocker arm. This intermediary component manages the hydraulic pressure and actuation timing, enabling variable valve actuation with a smaller, more efficiently filled fluid compartment, thus reducing the spool-up time requirement.
2Adaptability or versatility
If large fluid compartments are used in rocker arms, then variable valve actuation is enabled, but leakage increases and pumping burden increases
Solution Approach 1:
The patent separates the variable valve actuation function from the main fluid compartment, creating a dedicated hydraulic control mechanism with minimized fluid volume. This extraction reduces the total fluid volume subject to leakage, thereby decreasing the pumping burden required to maintain system pressure and compensate for leaks.
Solution Approach 2:
The patent applies local quality by concentrating the hydraulic control function in a specific, optimized location within the rocker arm assembly. The fluid compartment is strategically positioned and sized to provide sufficient actuation force while minimizing the overall fluid volume, thereby reducing leakage paths and pumping energy requirements.
3Stress or pressure
If traditional hydraulic systems are used, then pressurized oil can be supplied, but start-up delay occurs due to pump pressure issues
Solution Approach 1:
The patent implements a preliminary action by using a smaller fluid compartment that can be pressurized more quickly during engine start-up. The reduced fluid volume allows the pump to reach operating pressure faster, enabling the variable valve actuation system to become operational sooner without waiting for large fluid compartments to fill and pressurize.
Solution Approach 2:
The patent extracts the hydraulic control function from the main lubrication system, creating an independent, smaller fluid compartment that can be pressurized separately and more rapidly. This extraction allows the system to achieve pump pressure and activate variable valve control faster during start-up, reducing the delay associated with traditional large-compartment hydraulic 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
The solution enables efficient variable valve actuation, reduces the load on the starter motor during engine start-up, minimizes unfavorable torsional vibrations during engine shut-down, and allows for quicker engine start-up and improved fuel efficiency.
Implementation Method 1
The oil path is configured to supply hydraulic pressure within the rocker shaft to the channel
Implementation Method 2
the locking pin abuts a groove
Data Source
AI summary
A rocker arm assembly can comprise a rocker arm. A rocker shaft comprises a channel and an oil path enclosed in the rocker shaft. The oil path is configured to supply hydraulic pressure within the rocker shaft to the channel. Rotation-locking mechanism comprises a locking pin or pressure pin configured to slide in the channel. The oil path is configured to supply oil pressure to the locking pin or pressure pin within the rocker shaft. The locking pin can be configured to slide in the channel between a locked position, where the locking pin abuts a groove, and an unlocked position, where the locking pin is withdrawn into the channel. Or, a locking pin can be configured to slide in the rocker arm between a locked position abutting the locking groove and an unlocked position where the locking pin is withdrawn into the rocker arm.