Modular Hydraulic Valve Train Subassembly for Engine Assembly
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Solution Overview
Problem
The assembly and functional testing of hydraulic variable valve train subassemblies in internal combustion engines are complex and prone to errors, such as incorrect placement or omission of components, which complicates the manufacturing process and quality control.
Innovation Solution
The subassembly is designed as a modular unit where the guide bushing and valve element are fastened together, with the piston secured within, allowing for pre-installation testing and reducing assembly errors. This modular design includes a valve housing with a throttle opening and ball check valve, supported by a counterbore and fastening ring, enabling precise throttling characteristics and axial support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual components (valve element, guide bushing) are installed separately in the hydraulic housing, then assembly flexibility is maintained, but assembly errors such as incorrect placement or omission of components increase
Solution Approach 1:
The valve train is divided into modular subassemblies (guide bushing assembly, valve element assembly, piston assembly) that can be manufactured and tested independently before final installation in the hydraulic housing. This segmentation allows for pre-assembly verification and reduces the complexity of the final assembly process.
Solution Approach 2:
Multiple components (guide bushing, valve element, piston) are combined into a single integrated subassembly unit that is installed as one module in the hydraulic housing. This merging reduces the number of separate installation operations and eliminates assembly errors associated with installing individual components separately.
2Reliability
If subassembly is assembled and tested before installation in hydraulic housing, then defective parts can be rejected early and functional performance can be verified, but manufacturing process time and complexity increase
Solution Approach 1:
The subassembly is completely assembled and functionally tested before installation in the hydraulic housing. This preliminary action allows for early detection and rejection of defective parts, ensuring that only functional components proceed to final installation. The subassembly includes all necessary elements (guide bushing, valve element, piston) that work together as an integrated unit.
3Ease of operation
If valve element and guide bushing are installed separately, then installation flexibility is maintained, but risk of incorrect placement or omission of elements increases
Solution Approach 1:
The subassembly acts as an intermediary module that pre-combines the guide bushing and valve element in a verified, error-free configuration. This intermediary unit is then installed as a single block in the hydraulic housing, eliminating the risk of incorrect placement or omission that would occur with separate installation of individual components.
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 modular design simplifies assembly, reduces assembly errors, allows for early rejection of defective parts, and ensures uniform valve stroke distribution, resulting in a consistent hydraulic valve braking function with reduced variation across modules.
Implementation Method 1
The controlled braking of the piston and consequently of the gas exchange valve, which is spring-loaded in the closing direction, is accomplished by means of the throttle opening, which produces a strong throttling of the hydraulic medium displaced from the pressure chamber in the final closing phase of the gas exchange valve.
Implementation Method 2
the purpose of the ball check valve that is closed during the valve closing phase is to permit a fast initial opening speed of the gas exchange valve in that an essentially unthrottled, and accordingly comparatively large, volume flow can enter the pressure chamber when the valve ball is then opened.
Implementation Method 3
A subassembly of the valve train installed in a receptacle (2) of a hydraulic housing (3) includes a guide bushing (4) fastened in the hydraulic housing (3)... a piston (5) and a valve element (7)... Together with the end face (10) of the piston (5) distant from the gas exchange valve (1), this valve element (7) defines a hydraulic pressure chamber (11) in the guide bushing (4)
Data Source
AI summary
The invention proposes a subassembly of a hydraulic variable valve train of an internal combustion engine, having a guide bushing (4) that can be installed in a hydraulic housing (3), and having a piston (5) supported therein so as to be axially movable for actuating a gas exchange valve (1), and having a valve element (7) that, together with the end face (10) of the piston distant from the gas exchange valve, defines a hydraulic pressure chamber (11) in the guide bushing, wherein the valve element is a throttle check valve that allows hydraulic medium to flow out of the pressure chamber throttled by a continuously open throttle opening (16) and allows hydraulic medium to flow into the pressure chamber with little throttling by a ball check valve (17). The subassembly is intended to be implemented as a modular unit assembled outside of the hydraulic housing, wherein the guide bushing and the valve element are fastened to one another, and the piston is secured in a captive manner in the guide bushing.