ISO 20766-21:2023

Road vehicles - Liquefied petroleum gas (LPG) fuel system components - Part 21: Pressure and/or temperature sensors

This document specifies general requirements for the pressure and/or temperature sensors liquefied petroleum gas fuel, intended for use on the types of motor vehicles as defined in ISO 3833. It also provides general design principles and specifies requirements for instructions and marking. This document is applicable to vehicles (mono-fuel, bi-fuel or dual-fuel applications) using gaseous fuels in accordance with ISO 9162. It is not applicable to the following: a) fuel containers; b) stationary gas engines; c) container mounting hardware; d) electronic fuel management; e) refuelling receptacles. It is recognized that miscellaneous components not specifically addressed herein can be examined for compliance with the criteria of any applicable part of the ISO 20766 series, including testing to the appropriate functional tests. All references to pressure in this document are considered gauge pressures unless otherwise specified. This document applies to device which have a service pressure in the range of 110 kPa (butane rich at 20 °C) and 840 kPa (propane rich at 20 °C), hereinafter referred to in this document. Other service pressures can be accommodated by adjusting the pressure by the appropriate factor (ratio).

Véhicules routiers — Équipements pour véhicules utilisant le gaz de pétrole liquéfié (GPL) comme combustible — Partie 21: Capteurs de pression et/ou de température

General Information

• Status: Published
• Publication Date: 05-Feb-2023
• ICS: 43.060.40 - Fuel systems
• Technical Committee: ISO/TC 22/SC 41 - Specific aspects for gaseous fuels
• Drafting Committee: ISO/TC 22/SC 41/WG 6 - Fuel system components and refuelling connector for vehicles propelled by Liquefied Petroleum Gas (LPG)
• Current Stage: 6060 - International Standard published
• Start Date: 06-Feb-2023
• Due Date: 04-Oct-2022
• Completion Date: 06-Feb-2023

Overview

ISO 20766-21:2023 specifies general requirements for pressure and/or temperature sensors used in liquefied petroleum gas (LPG) fuel systems for road vehicles as defined in ISO 3833. The standard focuses on component-level design principles, identification and marking, and applicable tests to verify mechanical and environmental performance. It applies to mono-fuel, bi-fuel and dual-fuel vehicle applications that use gaseous fuels in accordance with ISO 9162, and addresses devices with service pressures between 110 kPa and 840 kPa (gauge pressures unless otherwise specified).

Key Topics

• Scope and applicability

  • Sensors intended for mobile road vehicles (not fuel containers, stationary engines, container mounting hardware, electronic fuel management or refuelling receptacles).
  • Recognizes that other components may be assessed using applicable parts of the ISO 20766 series.

• Marking and identification

  • Sensors shall carry clear, indelible markings including: manufacturer or agent name/trademark, model/part number, working pressure and temperature range, and year/month of fabrication.
  • Recommended additional markings: flow direction, fuel type, electrical ratings, certification symbol, type approval number, serial/date code and a reference to ISO 20766-21.

• Construction and assembly

  • Devices must withstand the maximum operating pressure and the specified operating temperature range.
  • Electrically operated sensors require insulation and isolation to prevent current conduction through LPG-containing parts; isolation resistance shall exceed 10 MΩ.
  • Materials in contact with the heat exchange medium must be compatible with LPG and able to withstand specific test pressures (e.g., 200 kPa for heat exchange fluid compatibility where applicable).

• Testing requirements (see ISO 20766-2 for procedures)

  • Hydrostatic strength: test pressure = 2.25 × working pressure.
  • External leakage, high temperature and low temperature leakage tests: leakage limits and conditioning periods defined; components must not exceed specified leak rates when tested at 150% of working pressure and designated temperatures.
  • Additional tests (corrosion, immersion, creep, ozone ageing, temperature cycling) apply as relevant and are indicated in the standard's test matrix.

Applications

• Use in LPG fuel systems for passenger cars, commercial vehicles and other mobile road vehicles using LPG as a fuel source.
• Integration into mono-, bi- or dual-fuel vehicle platforms to monitor pressure and/or temperature for safety, control and diagnostics.
• Helps manufacturers and suppliers demonstrate conformity to a recognized international benchmark for sensor design, marking and performance testing.

Related Standards

• ISO 20766-1 - General requirements and definitions for LPG fuel system components.
• ISO 20766-2 - Performance and general test methods referenced for hydrostatic, leakage and temperature tests.
• ISO 3833 - Vehicle types and definitions (referenced for vehicle applicability).
• ISO 9162 - Specifications for LPG fuels (class F).

ISO 20766-21:2023 provides a clear framework for designing, marking and testing LPG pressure and temperature sensors so manufacturers, system integrators and certification bodies can ensure safety, compatibility and regulatory compliance in automotive LPG applications.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 20766-21
First edition
2023-02
Road vehicles — Liquefied petroleum
gas (LPG) fuel system components —
Part 21:
Pressure and/or temperature sensors
Véhicules routiers — Équipements pour véhicules utilisant le gaz de
pétrole liquéfié (GPL) comme combustible —
Partie 21: Capteurs de pression et/ou de température
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Markings . 2
5 Construction and assembly .2
6 Tests . 2
6.1 Applicability . 2
6.2 Hydrostatic strength . 3
6.3 High temperature . . 3
6.4 Low temperature . 3
Bibliography . 4
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 41,
Specific aspects for gaseous fuels.
A list of all parts in the ISO 20766 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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INTERNATIONAL STANDARD ISO 20766-21:2023(E)
Road vehic
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