Engine Oil Flow System for Cylinder Deactivation
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Solution Overview
Problem
Existing engine oil systems face challenges in quickly transitioning between activated and deactivated modes due to trapped air in the latch pin hydraulic circuit, which increases transition time and complexity, and may lead to system degradation and maintenance issues.
Innovation Solution
The system incorporates a plurality of oil passages and an oil chamber within the engine cylinder head, with plugs having slots that fluidly couple these passages, allowing oil to flow through clearances and reduce air presence, thereby facilitating faster mode transitions and simplifying maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dual-function hydraulic lash adjuster is used to prime the latch pin hydraulic circuit, then mode transition capability is improved, but device complexity and maintenance difficulty increase
Solution Approach 1:
The system divides the hydraulic circuit into separate first and second oil galleries with distinct functions. The first oil gallery supplies hydraulic fluid to the hydraulic lash adjuster, while the second oil gallery supplies hydraulic fluid to the latch pin. This segmentation allows independent optimization of each circuit and simplifies maintenance by isolating potential failure points.
Solution Approach 2:
The patent extracts the air removal function from the hydraulic lash adjuster by providing a separate air venting path through the second oil gallery. This separates the pressure regulation function (handled by the hydraulic lash adjuster) from the air venting function (handled by the second oil gallery), reducing complexity of the lash adjuster itself.
2Reliability
If air is trapped within the latch pin hydraulic circuit, then system reliability decreases, but transition time increases
Solution Approach 1:
The system performs preliminary air removal by providing an air venting path through the second oil gallery before mode transition is required. The hydraulic fluid flow through the second oil gallery pre-vents air accumulation in the latch pin circuit, ensuring rapid and reliable transitions when needed.
Solution Approach 2:
The second oil gallery acts as an intermediary air venting path between the first oil gallery and the latch pin hydraulic circuit. It provides a dedicated route for air to escape without interfering with the primary pressure supply function of the first oil gallery.
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 configuration reduces air within the hydraulic system, decreases transition time, and enhances maintenance ease by allowing individual cylinder activation/deactivation and minimizing airflow into rocker arms, leading to a more consistent and efficient engine oil system operation.
Implementation Method 1
The latch pin hydraulic circuit of a switching rolling finger follower may be primed with hydraulic pressure while operating in the latched condition to facilitate the transition to the unlatched condition
Implementation Method 2
a first plurality of oil passages, a second plurality of oil passages, and an oil chamber, all disposed within an engine cylinder head; a plug housed within the oil chamber and including a slot fluidly coupled to a first section of the second plurality of oil passages; and a clearance formed between the plug and the oil chamber, the clearance fluidly coupling the first and second pluralities of oil passages. In this way, oil may flow through the clearance from the first plurality of passages to the second plurality of passages
Data Source
AI summary
Methods and systems are provided for an engine oil system of a cylinder head. In one example, an engine oil system may include a first oil gallery and a second oil gallery fluidly coupled to each other via a plurality of oil chambers. Each oil chamber includes a plug, and one or more of the plugs may include a slot shaped to direct a flow of engine oil from a solenoid valve to the second oil gallery.