Cylinder Head Valve Seat Cold Spray With Port Shielding Curtain

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Solution Overview

Problem

The cold spray method for forming valve seat films in internal-combustion engine cylinder heads often results in excess film formation in intake or exhaust ports, leading to variations in port size, reduced fuel efficiency, and decreased engine output performance.

Innovation Solution

A semimanufactured cylinder head with an annular shielding curtain portion is used, which projects from the port's edge toward the center, partially shielding the port and preventing excess film formation by directing scattered metal powder onto the curtain rather than the port's inner surface during the cold spray process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If metal powder is sprayed onto the valve seat portion using a cold spray method, then the valve seat film can be formed, but excess film is formed in the port causing deterioration of fuel efficiency and output performance

Engineering Contradiction:

Improvevalve seat film deposition precisionVSAvoidexcess film formation in port

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A shielding curtain portion is introduced as an intermediary element between the spray direction and the port interior. This curtain intercepts scattered metal powder before it can enter the port, allowing the valve seat film to be formed while preventing excess film accumulation that would harm engine performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The scattered metal powder that would normally become harmful excess film in the port is redirected to form the valve seat film on the target surface. The shielding curtain converts the harmful scattering effect into a beneficial deposition process by guiding the dispersed particles onto the valve seat portion

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach effectively suppresses excess film formation, ensuring precise valve seat film deposition and maintaining port integrity, thereby enhancing engine performance and fuel efficiency.

Implementation Method 1

spraying metal powder of the precipitation-hardened copper alloy onto an engine valve seating portion of a cylinder head using a cold spray method to provide the previously described film layer

Methodology Applied

Scientific EffectCold spray deposition: Deposition (physical)

Data Source

PatentUS11471937B2Method for manufacturing cylinder head, and semimanufactured cylinder head

Publication Date: 2022.10.18 NISSAN MOTOR CO LTD

AI summary

The disclosure includes manufacturing a semimanufactured cylinder head (3) having a shielding curtain portion (16g) and spraying metal powder (P) onto an annular valve seat portion (16f) using a cold spray method to form a valve seat film (16b). The shielding curtain portion (16g) projects in an annular shape from an annular edge portion of an opening portion (16a) of an intake port (16) or an opening portion (17a) of an exhaust port (17) toward the center (C) of the port. The annular valve seat portion (16f) is located on an outer side of the port than the shielding curtain portion (16g).