SMTC 3 950 001 Fuel System Test Method - Refueling

The standard “SMTC 3 950 001 Fuel system test method - Fuel filling” developed by SAIC MOTOR Technical Center (SMTC) is related to fuel system filling. This standard is applicable to bench testing for the purpose of complete vehicle and fuel system component certification, not for complete vehicle certification testing.

For the purposes of this standard,

• Dynamic unusable capacity refers to the volume of fuel remaining in the vehicle fuel tank when the vehicle is driven until the fuel is exhausted. It is not correct to determine the dynamic unusable capacity in a fixed test fixture. The remaining volume in a fixed fuel tank is usually larger than the dynamic unusable capacity.
• Liquid carryover is liquid fuel entering the evaporative emission canister through the fuel tank vent lines.
• One-click filling is the same as three-click filling except that the nozzle is not manually restarted after the first automatic shutdown. Filling is stopped after the first non-early automatic shutdown of the nozzle. The nozzle should be removed from the filling container and re-inserted into the nozzle tree no more than 3 seconds to 5 seconds after the single automatic shutdown.
• Pre-charging is the volume of fuel delivered to the tank prior to the filling test. The number of early shutdowns allowed during pre-charging does not apply.
• Early shutdown is the automatic shutdown of fuel dispensing equipment before 95 percent of nominal tank capacity is reached.
• Static undrained capacity is the volume of fuel remaining in the fuel tank after fuel has been drained through a fitted tank drain.
• Three-click priming is a priming in which the nozzle's automatic shut-off mechanism stops the flow of fuel into the tank at 95 percent or more of the nominal tank capacity, after which the nozzle is manually restarted and the process is repeated until a total of three consecutive automatic shut-offs have occurred. The time interval is 5 seconds.
• Nominal tank capacity is the volume of fuel available to the customer.
• The total volume of the fuel tank is the internal volume of the tank shell.

The purpose of this test procedure is to ensure that all aspects of the vehicle’s fuelling are considered and validated prior to the vehicle being released to market. The tests also ensure that legal fuelling requirements are met. Most of the tests are rig based but may be performed on the vehicle when required for extreme control. The fuelling report should be consulted during the test to ensure that all required results and conditions are recorded.

Testing should be conducted in a facility away from ignition sources. If indoors, the testing facility should be an explosion-proof room with adequate ventilation to meet all local safety codes.

The validity of the list in the table provided in the standard should be checked prior to testing as new types of nozzles are introduced from time to time. The latest fuel nozzles on the market should be used for testing. This list represents a variety of popular fuel dispensing nozzles but is only a small sample of the models available to fuel retailers. Specific concerns or market requirements regarding fuel system interaction with nozzles other than those listed in the table may require testing with additional nozzles. All nozzles used must comply with the European standard EN 13012 Construction and performance of automatic nozzles for use in fuel dispensers. All nozzles used to represent the North American market must comply with the standard SAE J285 Dispenser nozzle orifices for liquid fuels designed for use with spark-ignition and compression-ignition engines.

Fuel dispensing pumps must be capable of providing the flow rates given in the standard to simulate service station fuel dispensers in China and overseas. For other markets, the requesting engineer must specify the nozzles and flow rates to be used according to the countries in which the vehicles will be sold.

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 “SMTC 3 950 001 Fuel system test method - Fuel filling” standard with its trained and expert staff and advanced technological equipment.