ISO 2697:1999

Overview

ISO 2697:1999 - "Diesel engines - Fuel nozzles - Size 'S'" defines the essential dimensional requirements for size S fuel nozzles used in diesel engines. The standard ensures assembly compatibility and interchangeability of nozzles with corresponding nozzle holders. It applies to long‑stem hole nozzles (types A1 and A2) and pintle nozzles (type B). A1 and B are the preferred types; a non‑preferred short‑stem hole type (C) is included in Annex A. This second edition (1999) is a technical revision of the original 1974 edition.

Key topics and requirements

• Scope and nozzle types: Defines applicable nozzle classes (A1, A2, B; type C in Annex A) and states preferred options.
• Dimensional requirements: Specifies critical geometric dimensions and tolerances for size S nozzles - detailed in the standard’s figures and tables - to permit correct fit and function.
• Assembly interface: Covers cap‑nut geometry and assembly dimensions so nozzles can be secured into standard nozzle holders.
• Interchangeability rules: Ensures that compliant nozzles are interchangeable among nozzle holders of specified types.
• Position and angular tolerances: Includes assembly tolerances such as the reference dowel angular tolerance (±1°) and the angular relation between dowel hole and injection holes (±1°30′).
• Fuel feed and dowel features: Notes requirements for fuel feed grooves, dowel holes and optional features; certain features are required only for specific nozzle designs.
• Normative references: Directs users to related nozzle‑holder standards (ISO 2699, ISO 7026, ISO 7030) for compatible holder types and configurations.
• Manufacturer discretion: Leaves unspecified dimensions or additional features to manufacturers unless otherwise requested by the customer.

Applications and users

ISO 2697:1999 is intended for:

• Fuel nozzle manufacturers designing and producing size S nozzles to international tolerances.
• Diesel engine OEMs and engine designers specifying injectors and nozzle holders for engine assembly.
• Aftermarket suppliers and remanufacturers ensuring replacement nozzles will fit existing holders.
• Quality engineers and inspectors verifying dimensional compliance and interchangeability.
• Procurement and specification writers who require unambiguous mechanical interface definitions.

Practical benefits include reliable interchangeability, reduced assembly errors, consistent injector performance across suppliers, and simplified maintenance and parts sourcing.

Related standards

• ISO 2699 - Flange‑mounted fuel injectors, size S (types 2–6)
• ISO 7026 - Screw‑in nozzle holders for pintle nozzle size S (types 20, 21, 21.1, 27)
• ISO 7030 - Screw‑mounted nozzle holders (types 12–19)

Keywords: ISO 2697:1999, diesel engines, fuel nozzles, size S, nozzle interchangeability, nozzle holders, dimensions and tolerances, pintle nozzle, hole type nozzle.