ISO 6621-1:2018
ISO · 2018-02-01

Internal combustion engines - Piston rings - Part 1: Vocabulary

术语 ICS 01.040.43

1Key Takeaways

This document defines the most commonly used terms for piston rings. These terms designate either types of piston rings or certain characteristics and phenomena of piston rings. The terms and definitions in this document apply to piston rings for reciprocating internal combustion engines. They may also be used for pist…

2Expert Interpretation

An in-depth interpretation of the ISO 6621-1:2018 international standard terminology for piston rings, covering five major piston ring classification methods, 17 specific ring type definitions, and key parameter measurement specifications. This includes a comparison of compression ring and oil ring structural differences, surface treatment process requirements, and a multi-language terminology comparison table, among other professional and technical content.

Standard Framework and Technology Evolution

ISO 6621-1:2018, the third edition of the piston ring terminology system, replaces the 2007 edition (ISO 6626-1:2007). It primarily updates the accuracy of multilingual terminology translation and adds definitions for key technical parameters such as the Classification dimensions Main types Technical features Structural type Integral/combined Single-piece casting (3.1.2) vs. multi-component assembly (3.1.3) Functional type Compression ring/Oil ring Air tightness (3.1.4) vs. oil scraping function (3.1.5) Cross-sectional shape Rectangular/wedge-shaped Conventional rectangular ring (3.1.6) vs. Anti-Carbon Deposition Wedge Ring (3.1.7)

Typical Application Case

Keystone Ring (3.1.7) features a double-sided tapered design that automatically adjusts axial clearance during radial movement, effectively resolving the common ring sticking problem in diesel engines. The wedge angle must be within the 6° to 15° range, as specified in ISO 6624-1:2017.

Key Technical Parameter System

Parameter Category Symbol Definition Measurement Standard
Nominal Diameter d₁ Consistent with Cylinder Bore Diameter (3.2.1) ISO 286-1
Effective Free Gap m-s₁ Difference between Free Gap and Closed Gap (3.2.5) Figure 2/3
Contact Pressure FL Radial force (N/mm²) (3.2.7) ISO 6621-2

Implementation recommendations

  1. When selecting a ring type, the configuration and combination specifications in Tables 1 to 5 should be given priority. For example, the coil-spring-loaded bevelled-edge oil control ring (3.1.15) must also comply with ISO 6626-1/2.
  2. For measuring radial pressure distribution (3.2.6), it is recommended to use a ring gauge (3.4.1) operating on a standard plane (3.4.2).
  3. When implementing multilingual projects, the nine language terminology comparison tables in Appendix A should be checked, paying special attention to the new translations for Portuguese and Japanese.

Surface treatment process specifications

According to the requirements of Table 4, chrome plating treatment needs to be divided into:
- Full surface plating: Covering the entire outer surface (suitable for high-load engines)
- Partial inlay: Only treating specific contact areas (reducing costs)

3Version History

ISO 6621-1:1986 older 1986-12
ISO 6621-1:2007 older 2007-11
ISO 6621-1:2018 2018-02-01

4Standard Metadata

Standard Number
ISO 6621-1:2018
Status
Current (70% confidence)
Publisher
International Organization for Standardization (ISO)
Type
术语
Publication Date
2018-02-01
ICS Classification
01.040.43 (Road vehicle engineering (Vocabularies)) 
Adopted Standard
BS ISO 6621-1-2018,IDT

5Citation Network

0
Cite this standard
17
Referenced herein
Referenced by ISO 6621-1:2018
ISO 286-1:2010 ISO 6621-2:2003 ISO 6621-3:2000 ISO 6621-4:2015 ISO 6621-5:2013 ISO 6622-1:2003 ISO 6622-2:2013 ISO 6623:2013

6Frequently Asked Questions

What is ISO 6621-1:2018?
ISO 6621-1:2018 — Internal combustion engines - Piston rings - Part 1: Vocabulary is an international standard developed by International Organization for Standardization (ISO). This document defines the most commonly used terms for piston rings. These terms designate either types of piston rings or certain characteristics and phenomena of piston rings. The terms and definitions in this document apply to piston rings for...
What does ISO 6621-1:2018 cover?
This standard covers: This document defines the most commonly used terms for piston rings. These terms designate either types of piston rings or certain characteristics and phenomena of piston rings. The terms and definitions in this document apply to piston rings for reciprocating internal combustion engines. They may...
Who should use this standard?
This standard is intended for organizations, professionals, and stakeholders involved in various industries and sectors. It is applicable to manufacturers, service providers, regulatory bodies, and certification organizations.
What is the latest version of ISO 6621-1:2018?
The current published version is ISO 6621-1:2018, published on 2018-02-01. Always check for amendments or pending revisions.
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