Engine valve and method for manufacturing the same

By integrating a nitrided martensitic steel shaft with an austenitic steel cap, the engine valve addresses galvanic corrosion and wear resistance issues in fuel-efficient engines, ensuring durability and longevity.

JP2026109263APending Publication Date: 2026-07-01SUZUKI MOTOR CORP
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Patent Information

Application Number
JP2024224250
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Filing Date
2024-12-19
Publication Date
2026-07-01

AI Technical Summary

Technical Problem

Engines using CNG, LPG, or alcohol as fuel face significant corrosion issues due to the generation of moisture and acidic condensate, leading to galvanic corrosion between dissimilar metals, particularly affecting martensitic stainless steel engine valves.

Method used

The engine valve design incorporates a martensitic heat-resistant steel SUH11 shaft with a nitrided layer on its surface and an austenitic heat-resistant steel SUH35 cap, with the nitrided layer only formed on the shaft side to reduce potential difference and enhance wear resistance.

Benefits of technology

This configuration effectively suppresses galvanic corrosion and ensures adequate wear resistance by minimizing potential differences between the materials, thereby protecting the engine valve from corrosion and wear.

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Abstract

This invention provides an engine valve and a method for manufacturing the same, which can suppress galvanic corrosion even when dissimilar metals are joined, and which exhibits excellent wear resistance and corrosion resistance, for use in engines that use CNG, LPG, or alcohol as fuel. [Solution] The engine valve 10 of the present invention is a joint member in which a shaft portion 14 made of martensitic heat-resistant steel SUH11 and a umbrella portion 12 made of austenitic heat-resistant steel SUH35 are joined. A nitride layer is formed only on the surface of the base material on the shaft portion 14 side from the joint portion 13 between the shaft portion 14 and the umbrella portion 12, leaving the surface of the base material exposed on the umbrella portion 12 side from the joint portion 13.
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