Hydraulic Lash Adjuster Gravity Feed Apertures
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Solution Overview
Problem
Existing hydraulic lash adjusters face issues with fluid leakage during engine assembly and air ingestion into the high pressure chamber, leading to delayed refilling and reduced efficiency, especially when the engine is inverted or assembled dry.
Innovation Solution
Incorporating a normally-open check valve and a recirculation passageway with a gravity feed arrangement, including offset apertures and a valve mechanism that allows fluid to flow back into the reservoir, ensuring quicker filling and preventing air ingestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a central aperture is used in the socket to feed fluid from the push tube into the reservoir, then the structure is simple, but fluid leakage occurs during engine assembly and air ingestion into the high pressure chamber
Solution Approach 1:
The single central aperture is segmented into multiple apertures arranged in a circular pattern. This segmentation allows the formation of multiple fluid channels that work together to prevent leakage and air ingestion while maintaining manufacturing simplicity. The multiple apertures create a distributed feeding system that is more reliable than a single aperture.
Solution Approach 2:
The apertures are positioned asymmetrically relative to the push tube, with specific apertures located closer to and farther from the push tube. This asymmetric arrangement creates optimized fluid flow paths that prevent air ingestion into the high pressure chamber while maintaining ease of manufacture.
2Adaptability or versatility
If the engine is inverted or assembled dry, then assembly flexibility is improved, but fluid leakage and air ingestion occur leading to delayed refilling
Solution Approach 1:
The socket is designed with multiple apertures and an intermediate chamber that pre-establish fluid pathways before the lash adjuster is installed in the engine. This preliminary design ensures that fluid can be properly fed into the reservoir during assembly regardless of engine orientation, preventing air ingestion and eliminating the need for delayed refilling operations.
Solution Approach 2:
An intermediate chamber is introduced between the apertures and the high pressure chamber. This intermediary structure allows fluid to be fed through multiple apertures into the intermediate chamber, which then distributes fluid to the reservoir, preventing direct air ingestion into the high pressure chamber and enabling quick filling regardless of assembly position.
3Speed
If external pressure is applied to fill the high pressure chamber, then filling speed is improved, but the oil pump demand increases
Solution Approach 1:
The socket design with multiple apertures and intermediate chamber enables the reservoir to self-fill from the push tube without requiring external pressure from the oil pump. The gravity feed arrangement through multiple apertures allows fluid to naturally flow into the reservoir, eliminating the need for high oil pump demand while maintaining quick filling speed.
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 quicker filling of the high pressure chamber and prevents air ingestion, optimizing the hydraulic lash adjuster's performance by allowing it to maintain fluid levels without external pressure, reducing the demand on the oil pump and minimizing assembly delays.
Implementation Method 1
The apertures of the second pair of apertures are offset from the apertures of the first pair. The second pair of apertures provide a surface tension seal to the top surface of the leakdown plunger and route fluid into the reservoir.
Implementation Method 2
The socket includes a gravity feed arrangement to feed fluid to the reservoir of the leakdown plunger. The gravity feed arrangement comprises at least one aperture defined through the socket.
Data Source
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AI summary
A hydraulic lash adjuster assembly constructed in accordance to one example of the present disclosure includes a bucket and a hydraulic lash adjuster. The hydraulic lash adjuster is received in the bucket and has a body, a leakdown plunger and a socket. The leakdown plunger is received in the body. The socket is received by the leakdown plunger. The socket and leakdown plunger define a reservoir therebetween. The socket includes a gravity feed arrangement to feed fluid to the reservoir of the leakdown plunger.