SMTC 9 951 002 Technical Requirements for Plastic Fuel Tank Assembly

The standard “SMTC 9 951 002 Technical requirements for plastic fuel tank assembly” developed by SAIC MOTOR Technical Center (SMTC) describes the functional, performance, reliability, durability and verification requirements of plastic fuel tank assembly. This standard applies to multi-layer fuel tank assembly consisting of a combination of the following types of parts: fuel tank body, valves, fuel line, vapor line and connecting connections, etc. This standard applies to a passenger car, commercial derivative (up to 3,5 tons gross vehicle weight) and 4×4 off-road vehicle.

This standard is considered as minimum requirements. Additional tests requested by SMTC fuel system engineers and suppliers are included in the drawing requirements based on the specific needs of the project.

For the purposes of this standard,

Fuel tank capacity refers to the volume of fuel that the customer can use.
Fuel tank dead volume refers to the volume of fuel that is not available to the customer.
The total volume of the fuel tank is the internal volume of the tank shell.
The expansion volume of the fuel tank is the ratio of the full volume of the fuel tank to the full volume of the fuel tank after subtracting the built-up part volume of the fuel tank, the fuel tank dead volume and the nominal volume of the fuel tank.
Fuel leakage refers to the linear or dripping fall of fuel in the self-igniting tank.
Fuel permeation is the fuel loss due to molecular diffusion in the fuel tank.
Fuel tank working pressure refers to the pressure above the liquid level in the fuel tank under normal vehicle operating conditions (in short, working pressure).

The fuel tank assembly is intended to:

Receiving and storing fuel
Detecting fuel quantity
To provide fuel to the engine
Returning unused fuel to the storage tank
Providing the capacity to manage fuel vapor storage, control and recovery for gasoline and ethanol flexible fuels only

The fuel tank assembly must comply with the requirements of the markets in which the product will be sold.

The fuel tank assembly is to provide fuel receiving and storage capacity. The fuel subsystem must have the following features:

High quality fuel fill specifications (where applicable).
Accurate indication of amount of stored fuel (where applicable).
Noise, thermal and odor control.
Clean fuel delivery to the engine based on powertrain requirements (where applicable).
Managed production, storage and escape of fuel vapor from the fuel subsystem (where applicable).
The SMTC provides the on-board interface hardware or requirements for fuel pressure regulation, return fuel control, vapor purge control, and vapor leak detection (where applicable).
The design and operation of the fuel tank assembly shall comply with applicable government safety regulations and corporate safety objectives.
The functional context diagram of the fuel tank assembly is shown in the figure in the standard.

The exterior colour of the fuel tank assembly and components shall preferably be black or match the underbody. Support belts shall be free from cracks/breaks, splits, flaking, peeling, burrs or any unreasonable wear after any testing specifying this requirement.

The physical and functional contents required for the fuel tank assembly are specified in the standard. The physical contents are specified for the fuel tank shell, fuel lines, tank straps, control valve, heat shield, fasteners and mounting hardware where required, labels; filler pipe, carbon canister, fuel filter, air filter, thermocouple, as well as additional components such as dust caps, bags and rubber bands (for transportation).

The fuel tank assembly must have the following functions:

Must refuel and store fuel safely.
Must capture fuel supply vapors in applications where vapor chamber is a design requirement for integral assembly (gasoline only).
It should be constructed to reduce hydrocarbon emissions where necessary.
It shall support the modular reservoir assembly function in sensing the fuel level and provide a signal of the amount of stored fuel.
Must detect tank pressure and enable vapor leak detection in applications where on-board diagnostics and integrated tank pressure sensor are required (petrol only).
It must support the modular reservoir assembly function of supplying clean fuel to the engine on demand according to the pressure and flow requirements of the powertrain and returning excess fuel to the storage tank.
It must manage vapor by limiting the formation and escape of fuel vapor and by transporting and storing the vapor for later cleaning and combustion by the powertrain.
It must manage heat buildup in the fuel resulting from ambient and underbody conditions.
Must filter the scavenge air (the scavenge air filter is part of the integral fuel tank assembly).

Among the numerous tests, measurements, analyses and evaluation studies carried out for businesses in various sectors, our organization also provides testing services defined in the standard “Technical requirements for SMTC 9 951 002 Plastic fuel tank assembly” with its trained and expert staff and advanced technological equipment.