ISO 20766-5:2023

Road vehicles - Liquefied petroleum gas (LPG) fuel system components - Part 5: Fuel selection system and electrical installations

This document specifies general requirements and definitions of liquefied petroleum gas fuel components (fuel selection system and electrical installations, 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) 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 devices 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 5: Système de sélection du combustible et installations électriques

General Information

• Status: Published
• Publication Date: 27-Aug-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: 28-Aug-2023
• Due Date: 04-Jan-2024
• Completion Date: 28-Aug-2023

Overview

ISO 20766-5:2023 provides definitions and general requirements for liquefied petroleum gas (LPG) fuel selection systems and electrical installations used on road vehicles (as defined in ISO 3833). The standard applies to mono‑fuel, bi‑fuel and dual‑fuel vehicle applications using gaseous fuels in accordance with ISO 9162. It specifies design principles, marking and instructions, and identifies mandatory tests and performance criteria for safe, reliable operation within the service pressure range of 110 kPa to 840 kPa.

Key exclusions include fuel containers, stationary gas engines, container mounting hardware and refuelling receptacles.

Key Topics

• Scope and applicability: Components intended for vehicle use (mono/bi/dual‑fuel) and the pressure range covered. Other service pressures can be accommodated by adjusting the pressure by the appropriate factor.
• Marking requirements: Components must allow traceability by marking manufacturer name/trademark, model/part number and operating specifications (temperature range, electrical rating). Recommended markings include fuel type, certification symbol, approval numbers and a reference to ISO 20766-5.
• Construction and assembly:
  • Systems must withstand maximum operating pressure and the specified temperature range.
  • Electrically operated fuel selection systems shall plug into the harness using the same connector or an adapter.
  • Electrical insulation must prevent current flow through LPG-containing parts; isolation resistance shall exceed 10 MΩ.
  • Wiring and connectors must be suitable for automotive use, protected from abrasion, flexing and heat, and secured at intervals not exceeding 40 cm.
  • Overload protection: at least one dedicated fuse sized for the system with location documented in the operator manual.
• Electrical connection quality: Sealed connectors with positive locking, manufacturer‑recommended connectors, or soldered connections protected by heavy wall shrink insulation are required. The use of electrical tape for bare connections is not permitted.

Tests

ISO 20766-5 references required tests and criteria, many of which are performed per ISO 20766-2. Notable tests and acceptance criteria included in the document:

• Continued operation: 50 000 switching operations at room temperature with cycles apportioned 80% ambient, 10% at -40 °C and 10% at 85 °C; successful completion requires passing the insulation resistance test.
• Vibration resistance: Components with moving parts or printed circuit boards must remain undamaged and operational while powered during vibration tests.
• Temperature cycle: 96‑hour cycles between minimum and maximum operating temperatures with 120 min cycle time; component must be in working condition and meet insulation criteria afterward.
• Insulation resistance: Apply 500 V d.c. for 60 s; minimum allowable resistance 240 kΩ.
• Minimum operating voltage: ≤ 8 V for 12 V systems and ≤ 16 V for 24 V systems while in working condition.

Applications

ISO 20766-5:2023 is directly applicable to:

• Automotive OEM and aftermarket components for LPG fuel selection and associated electrical installations.
• Design verification and type approval testing of LPG switching devices, wiring harness interfaces and electrical modules used in mono/bi/dual‑fuel vehicles.
• Installation guidance for vehicle converters, system integrators and certification bodies evaluating component compliance.

Related Standards

• ISO 20766 series (all parts), including ISO 20766-1:2018 (general requirements) and ISO 20766-2:2018 (performance and test methods)
• ISO 3833 (vehicle types and definitions)
• ISO 9162 (gaseous fuel requirements)
• Relevant material and fuel standards referenced in the ISO 20766-5 bibliography (for example ISO 11114-2)

Compliance with ISO 20766-5:2023 helps ensure safe electrical integration, robust switching performance and traceable marking for LPG fuel systems used in road vehicles.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 20766-5
First edition
2023-08
Road vehicles — Liquefied petroleum
gas (LPG) fuel system components —
Part 5:
Fuel selection system and electrical
installations
Véhicules routiers — Équipements pour véhicules utilisant le gaz de
pétrole liquéfié (GPL) comme combustible —
Partie 5: Système de sélection du combustible et installations
électriques
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 Marking . . 2
5 Construction and assembly .2
6 Tests . 3
6.1 Applicability . 3
6.2 Continued operation . 4
6.3 Vibration resistance . . 4
6.4 Temperature cycle test . 4
6.5 Insulation resistance. 4
6.6 Minimum operating voltage . 4
Bibliography . 5
iii
Foreword
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www.iso.org/iso/foreword.html.
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.
iv
INTERNATIONAL STANDARD ISO 20766-5:2023(E)
Road vehicles — Liquefied petroleum gas (LPG) fuel system
components —
Part 5:
Fuel selection system and electrical installations
1 Scope
This document specifies general requirements and definitions of liquefied petroleum gas fuel
components (fuel selection system and electrical installations, 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) 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 devices 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).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 20766-1:2018, Road vehicles — Liquefied petroleum
...