Vented Hydraulic Lifter Spring Chamber Design
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Solution Overview
Problem
Existing hydraulic valve mechanisms for internal combustion engines face inefficiencies due to oil pumping in the lost motion spring chamber during deactivation mode, which reduces engine efficiency and causes stability and noise issues, and they are not compatible with engines having limited axial space or large pushrod engagement angles, as well as failing to account for mechanical lash variability.
Innovation Solution
A deactivating hydraulic valve lifter design that includes a lost motion coil spring in an annular chamber with a vent to discharge oil and an oil passage bypassing the chamber, along with an expansion ring to set mechanical lash, ensuring efficient operation and compatibility with various engine designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the lost motion spring is disposed between the outer body and inner locking pin housing, then the overall length of the DHVL is reduced, but oil pumping occurs in the spring chamber during deactivation mode
Solution Approach 1:
The patent segments the DHVL into distinct functional zones: an oil supply passage that bypasses the lost motion spring chamber, separating the hydraulic element assembly oil supply from the spring chamber. This allows the spring chamber to be vented to atmosphere rather than filled with oil, eliminating oil pumping losses while maintaining the compact design.
Solution Approach 2:
The patent extracts the oil from the lost motion spring chamber by providing a vent passage that opens to the atmosphere. The oil supply passage is routed to bypass the spring chamber entirely, removing the harmful oil pumping effect while preserving the compact spring placement between the outer body and inner locking pin housing.
2Object-affected harmful factors
If the tower extension is used to accommodate the lost motion spring, then the spring chamber can be vented, but the axial space requirement increases
Solution Approach 1:
Instead of extending axially with a tower structure, the patent routes the oil supply passage through a different spatial path that bypasses the spring chamber. The passage travels through the body and pin housing structure in a non-axial direction, allowing the spring chamber to remain compact while still being vented to atmosphere.
3Quantity of substance
If the oil passage passes through the lost motion spring chamber, then the chamber is filled with oil, but this causes valve train stability issues and wear
Solution Approach 1:
The patent removes oil from the lost motion spring chamber by providing a vent passage that opens to the atmosphere. The oil supply passage is specifically routed to bypass the spring chamber, extracting the harmful oil presence that causes cavitation, wear, and stability issues while maintaining proper lubrication elsewhere in the mechanism.
4Length of moving object
If the locking mechanism is made compact without a tower, then axial space is reduced, but mechanical lash variability increases
Solution Approach 1:
The patent incorporates an adjustable expansion ring that can be set to different positions to compensate for manufacturing variability in the locking mechanism components. This adjustable element dynamically adapts the mechanical lash to optimal values, maintaining precision despite the compact design without a tower extension.
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 minimizes oil pumping during deactivation, enhances engine efficiency, reduces noise, and allows for adjustable mechanical lash, accommodating engines with limited space and large pushrod angles, thereby improving overall performance and compatibility.
Implementation Method 1
a lost motion spring, which may be a coil spring, disposed in an annular chamber formed within the envelope of the mechanism between the body and the pin housing
Implementation Method 2
A vent of the annular chamber permits ready discharge of any accumulated oil from the chamber on the first lost-motion stroke of the body and thereafter
Implementation Method 3
An oil passage is provided from an engine gallery to the hydraulic element assembly, at the interface between the cup member and pin housing thereby bypassing the lost motion annular chamber
Implementation Method 4
a conventional hydraulic lash adjustment element, also referred to herein as a hydraulic element assembly (HEA), disposed between a plunger and a cup member
Data Source
AI summary
A deactivating hydraulic valve mechanism includes a hydraulic element assembly disposed within cup within a pin housing slidably disposed within a bore in a body. A transverse bore in the pin housing contains selectively-retractable locking pins that engage a locking feature in the body to selectively lock together the body and the pin housing. A lost motion spring is disposed in a vented annular chamber between the body and the pin housing. An oil passage from an engine gallery to the hydraulic element assembly includes an axial component formed in the cup and bypasses the lost motion chamber. A ring holds the lifter assembly together and also sets mechanical lash. The ring may combine a standard-thickness ring and a shim selected to provided a predetermined amount of mechanical lash in the assembled mechanism to ensure facile engagement and disengagement of the locking pins in the body.