CSA ANSI NGV 6.1:2018 pdf free download – Compressed natural gas (CNG) fuel storage and delivery systems for road vehicles
4.3.2 Failure modes and effects analysis (FMEA)
The system designer shall develop a system level Design FMEA utilizing component reference information as available (e.g., component FMEAs, quality history). The installer shall follow a Process FMEA. The documents shall be kept on file per the requirements of the quality system referenced in Clause 4.3. (See Annex A, Sample Design FMEA.) Note: FMEA is a methodology used in the automotive industry to identify potential failure modes and to recommend changes in design, manufacturing, inspection, or testing, which eliminate such failure modes or minimize their effects. FMEA is applied to both device design and to the manufacturing and assembly process to identify corrective actions that improve device reliability and safety. Available references include SAE J1739, Potential Failure Mode and Effects Analysis in Design (Design FMEA), Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA).
4.4.1 Essential to a successful system design is an understanding of the system requirements and service conditions. For this purpose, system engineering disciplines should be applied to the development of the CNG fuel system. Systems engineering in a vehicle context focuses on analyzing and capturing customer needs and then cascading these needs into required vehicle functionality, which are translated to system requirements and service conditions. These system requirements are identified early in the product development cycle in order to show that a higher level assemblage, or collection of components, results in a successful system. Systems Engineering involves a “holistic” or top-down approach to analyzing and extracting system requirements based upon:
a) customer wants and needs;
b) functional performance requirements;
c) service life and duty cycle requirements;
d) expected operating environment and service conditions;
e) other inputs and interfaces (e.g., fuel composition, fueling infrastructure);
f) relevant industry standards; and
g) legal and regulatory requirements.
4.4.2 In the case of a CNG fuel system, the highest level system is the vehicle. The above process shall first be conducted at the vehicle level. The vehicle level requirements are then cascaded to the fuel system. The overall requirements of the fuel system shall also be in harmony with other vehicle criteria and interactions with other vehicle systems. The next step is to translate the requirements into engineering parameters that relate to system performance. Once the fuel system requirements are determined, the cascade continues to show that the detailed component designs align or exceed the system requirements and service conditions.
4.4.3 The system engineering approach was utilized to identify the key design requirements in Clause 5. It is highly recommended that the system engineering disciplines are considered for the specific customer and vehicle application. For a starting point of further consideration, Annex D provides a general listing of service conditions to consider in the system design in addition to the requirements in Clause 5. It should be noted that specific vehicle designs may have other or more service conditions. The designer should use system engineering to prepare a set of service conditions specific to the application. Extreme duty or high-cycle service are two fairly common special service conditions.