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QC/T 1121-2019 PDF in English

QC/T 1121-2019 (QC/T1121-2019, QCT 1121-2019, QCT1121-2019)
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QC/T 1121-2019: PDF in English (QCT 1121-2019)

QC/T 1121-2019
ICS 43.040.10
T 36
Plastic fuel tank for vehicle
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 7
1 Scope ... 8
2 Normative references ... 8
3 Terms and definitions ... 8
4 Technical requirements ... 9
5 Test method ... 12
6 Inspection rules ... 18
7 Signs, packaging, transportation, storage ... 19
Appendix A (Normative) Refractory brick size and technical requirements ... 21
Appendix B (Normative) Fire resistance test ... 22
Appendix C (Normative) Vacuum pressure alternating curve ... 24
Plastic fuel tank for vehicle
1 Scope
This standard specifies the performance requirements and test methods for plastic fuel
tank for vehicle.
This standard is applicable to the plastic fuel tanks of categories M and N vehicles. The
plastic fuel tanks of other vehicles can be implemented with reference to this standard.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB 18296 Safety property requirements and test methods for automobile fuel tank
and its installation
GB 18352.6-2016 Limits and measurement methods for emissions from light-duty
vehicles (CHINA 6)
3 Terms and definitions
The terms and definitions, as defined in GB 18296 and GB 18352.6-2016, as well as
the following terms and definitions, apply to this standard.
Plastic fuel tank
An independent tank assembly that is assembled from the plastic fuel tank, fuel filler
pipe, fuel filler inlet, fuel tank cap, pipe joints and other accessories AND fixed on
the vehicle for storing fuel (hereinafter referred to as the fuel tank).
Unusable volume
The volume of the fuel tank, which is occupied by the fuel that cannot be sucked out
by the fuel supply device.
Vehicle of category I
Category M1 vehicles, which have no more than six seats including the driver's seat
AND a maximum design gross mass of no more than 2500 kg.
4 Technical requirements
4.1 General requirements
The fuel tank shall comply with the provisions of this standard. It shall be manufactured
according to the drawings and technical documents, which are approved by the
prescribed procedures.
If the user has other special requirements, it shall be negotiated between the
manufacturer and the user; corresponding provisions shall be made in the product
drawings and related design documents.
4.2 Appearance of fuel tank
The appearance of the fuel tank is inspected visually.
4.3 Fuel tank material
4.3.1 The material of the fuel tank shall be resistant to fuel for vehicles.
4.3.2 Fuel tanks are made of high temperature and low temperature resistant materials.
4.4 Fuel tank capacity
It shall be tested according to 5.2; the capacity tolerance is ±3% of the rated capacity.
4.5 Automatic pressure compensation device of fuel tank
The fuel tank shall have an automatic pressure compensation device, which can
automatically compensate the working pressure or safety pressure of the fuel tank, such
as vent valve, safety valve, etc.
4.6 Requirements for preventing loss of fuel tank cap
The fuel tank cap shall be fixed onto the filler pipe. In the event of a missing fuel tank
cap, this requirement is considered to be complied with, if there are means to prevent
excessive evaporation of fuel and fuel spillage. Specifically, the following methods can
be used:
a) A non-removable fuel tank cap, that opens and closes automatically.
b) Any other measure having the same effect, for example (including but not limited
to), pull-strap fuel tank cap, chain-type fuel tank cap, etc., OR a fuel tank cap that
uses the same key as the ignition key (in this case, only when the fuel tank cap is
locked, can the key be pulled out of the fuel tank cap). But for other vehicles than
the categories M1 and N1 vehicles, it is not enough to only use the pull-strap type
fuel tank cap or chain type fuel tank cap as a measure.
4.7 Anti-static requirements for fuel tanks
The design and installation of the fuel tank and its accessories shall avoid any fire,
which is caused by static electricity. For fuel tanks containing fuel with a flash point
below 55 °C, it shall take necessary discharge measures.
4.8 Fuel tank ventilation performance
4.8.1 Static ventilation performance of the gasoline tank: Simulate the slope and level
conditions of the gasoline vehicle in the front, rear, left, right slopes of 20% (15% for
motor vehicles, whose total mass is less than 1.2 times the curb weight), to carry out
test according to 5.3. The pressure difference -- between the inside and outside of the
gasoline tank -- shall be less than or equal to 10 kPa; meanwhile, there shall be no liquid
fuel overflowing into the carbon tank.
4.8.2 Negative pressure ventilation performance of the fuel tank: The outside air shall
be able to flow into the fuel tank, through the ventilation device. The test shall be carried
out, according to 5.4. The pressure difference -- between the inside and outside of the
fuel tank -- shall be greater than or equal to -2.5 kPa.
4.9 Fuel tank tightness
Carry out the test according to 5.5. There shall be no air bubbles.
4.10 Fuel tank over-turnability
During normal use of the vehicle, the fuel shall not overflow from the fuel tank cap, nor
shall it overflow from the automatic pressure compensation device. When the
overturning test is carried out according to 5.6, fuel leakage is allowed; however, the
leakage rate shall not exceed 30 g/min. The gasoline fuel tank cap is not allowed to
have fuel leakage.
4.11 Cleanliness of the inner surface of fuel tank
The test shall be carried out in accordance with 5.7. The insoluble solid impurities inside
the fuel tank shall be less than or equal to 0.04 g.
4.12 Refueling performance
The test shall be carried out in accordance with 5.8. The fueling volume for the first
Carry out the test according to 5.16; the fuel tank shall not leak.
4.22 Emission of pollutants from fuel tank
Conduct the test according to 5.17. The emission of evaporative pollutants during the
refueling process shall not exceed 0.04 g/L.
5 Test method
5.1 Appearance of fuel tank
The surface of the fuel tank shall be smooth and free of burrs; there shall be no
insufficient molding. There shall be no knife marks, scratches, scald marks on the tank;
there shall be no insoluble foreign particles and impurities, that affect the performance
of the fuel tank.
All assembly parts and welded parts on the fuel tank assembly shall not have any
manufacturing defects.
5.2 Capacity measurement of fuel tank
5.2.1 Measurement of unavailable capacity
The fuel tank is installed according to the installation state; the vehicle or test bench is
adjusted to a horizontal position. Add an appropriate amount of fuel into the fuel tank;
then make the fuel pump work normally, until the fuel cannot be pumped out. Measure
the pumped fuel volume; the difference between the added fuel volume and the
pumpable fuel volume is the unavailable capacity.
5.2.2 Capacity measurement
After completing the unavailable capacity test, keep the vehicle (or test bench)
stationary; fill the gasoline tank with gasoline at a rate of 40 L/min, OR fill the diesel
tank with diesel at a rate of 40 L/min. After the first gun jump, carry out 2 consecutive
refills; the interval shall be less than 5 s; the volume of fuel added by three gun jumps
is the rated capacity.
5.3 Static ventilation test of gasoline tank
In an environment of 23 °C ± 5 °C, fill the fuel tank with fuel of rated capacity. The
temperature of the fuel added is 15 °C ± 2 °C; the fuel shall meet the requirements of
Appendix K in GB 18352.6-2016. It is placed in the ambient temperature box, which
has a temperature of 40 °C ± 2 °C. After being fixed according to the installation state,
keep it sloped in the front, rear, left, right at 20%, respectively (15%for motor vehicles
whose total mass is less than 1.2 times the curb weight) and horizontal conditions, for
12 hours. If the fuel temperature in the fuel tank does not reach 40 °C, continue the test,
until the oil temperature inside the fuel tank reaches 40 °C. Monitor the inside pressure
of the fuel tank at a frequency greater than or equal to 10 times/s. After the test, measure
the volume of spilled fuel.
5.4 Negative pressure ventilation test of fuel tank
Install the fuel tank on the test bench. Add water of rated capacity to the fuel tank.
Connect the suction pipe to the bottom of the fuel tank. Connect the pressure sensor to
the upper part of the fuel tank. The pressure sensor is not allowed to be immersed in
water. Seal the remaining connections to the fuel tank, to keep the ventilation device
working properly. Pump water out, at a rate equal to the maximum flow rate of the
engine for 2 hours OR until the water inside the fuel tank is drained. Record the internal
pressure of the fuel tank.
5.5 Leakage test of fuel tank
The fuel tank is placed in the clear water pool. Feed the air of 30 ~ 35 kPa in the fuel
tank. After the water surface is calm for 1 min, keep the pressure for 1 min; no bubbles
shall come out.
Other equivalent sealing test methods may be used.
5.6 Overturning test of fuel tank
5.6.1 Fix the fuel tank and all its accessories on the test bench, according to the
installation method on the vehicle. An automatic pressure compensation device shall
also be installed.
5.6.2 The fuel tank shall rotate about an axis, which is parallel to the longitudinal axis
of the vehicle.
5.6.3 The test shall be carried out twice. Once filling the fuel tank with test fluid up to
90% of the rated capacity of the fuel tank, fill the fuel tank with 30% of the rated
capacity of the fuel tank for the second time. As a non-flammable liquid, its viscosity
and density are similar to those of normal fuel (water can be used).
5.6.4 The fuel tank is turned 90° to the right from its installed position. Keep at this
position for at least 5 minutes. Then continue to turn 90° in this direction. Keep this
fully inverted position for at least 5 min. Return the fuel tank to right position. Drain
the test liquid, that fails to flow back to the fuel tank from the vent hole. Add it if
necessary. Then turn the fuel tank 90° to the left in the opposite direction. Hold at this
position for at least 5 min. Then continue to turn 90° in this direction. Keep in this fully
inverted position for at least 5 min.
Overturning speed: For each 90° turning, the turning time is 1 ~ 3 min.
After each state is stable for 15 s, use a stopwatch to start timekeeping. Use a measuring In each test, the installation of the fuel tank and its accessories shall simulate
the actual installation state as much as possible and be fixed on the test bench. If the
vehicle is equipped with components, that affect the spread of fire, it shall also be
installed. All openings are to be sealed during the test and the ventilation device shall
remain in working condition. Fill the fuel tank with the same designation of fuel as the
vehicle's oil, to reach 50% of its rated capacity.
5.13.3 Combustion flame requirements: Ignite the motor fuel in a fuel sump. The
amount of fuel in the fuel sump is to be sufficient, to ensure that it can last until the end
of the test, under free burning conditions.
5.13.4 Fuel sump size requirements: Ensure that all edges of the fuel tank are exposed
to flames; the length and width of the fuel sump shall exceed the projection line of the
fuel tank, on the horizontal plane by 200 ~ 500 mm. The side wall of the fuel sump is
not allowed to be 80 mm higher than the fuel level.
5.13.5 Place the fuel sump, which is filled with fuel, at the lower part of the fuel tank.
The distance -- between the fuel level and the bottom of the fuel tank shall be the same
as the height of the fuel tank from the ground, when the vehicle is empty. The test fuel
sump and other devices can move freely.
5.13.6 In stage C of the test, place a compartment at 30 mm ± 10 mm above the fuel
level, to cover the fuel sump.
See Appendix A, for the structure and materials of the compartment. There shall be no
gaps between the refractory bricks; they shall be supported on the fuel sump in the
following way: The holes on the refractory bricks shall not be blocked; the length and
width of the compartment brackets are 20 ~ 40 mm smaller than the corresponding
dimensions of the inner wall of the fuel sump, so that a ventilation gap of 10 ~ 20 mm
is reserved, between the frame and the side wall of the fuel sump.
5.13.7 If the test is carried out outdoors, adequate wind protection measures shall be
taken; the wind speed on the fuel liquid surface in the fuel sump shall not exceed 2.5
km/h. Before starting the test, preheat the compartment to 35 °C ± 5 °C. The same test
conditions are guaranteed at each test stage; the refractory bricks shall be wetted.
5.13.8 The test process includes four stages (see Appendix B for details):
Stage A: Preheating (see Figure B.1). Light the fuel in the fuel tank, at a distance of
at least 3 m from the test fuel tank. After preheating for 60 s, move the fuel sump to
the lower part of the fuel tank.
Stage B: The fuel tank is directly exposed to flames (see Figure B.2). Expose the
fuel tank directly to a free-burning flame for 60 seconds.
Stage C: The fuel tank is indirectly exposed to flames (see Figure B.3). Immediately
after completion of stage B, cover the fuel sump with a compartment. Expose the
5.16 Bursting test
The fuel tank is installed on the test frame. The inside is filled with water. The fuel
tank's exhaust port is sealed. The internal pressure of the fuel tank is raised from 0 to
294 kPa, within 3 ~ 6 min. Then the pressure is held for 1 min. During the test, pay
attention to whether the fuel tank has leakage.
5.17 Refueling pollutant emission test
5.17.1 Fill 10% of the fuel tank's rated capacity to the fuel tank, that has passed the leak
test. Simulate the installation state, to place it in an aging tank, at an ambient
temperature of 23 °C ± 5 °C for 6 ~ 36 hours.
5.17.2 Pretreat the carbon canister to make the carbon canister adsorb to the critical
point of 2 g. The specific method shall comply with the provisions of I5.6 in Appendix
I of GB 18352.6-2016.
5.17.3 Install the fuel tank assembly and carbon canister on the test bench, which
simulates the state of the whole vehicle. Place them in the test chamber.
5.17.4 In the 23 °C ± 3 °C test chamber, the handle of the refueling gun shall be
approximately vertical to the ground, AND inserted into the bottom of the refueling
pipe as much as possible. Use 20 °C ± 1 °C fuel, at a rate of 37 L/min ±1 L/min, to
transfer fuel, to at least 85% ± 0.5 L of rated capacity. If the refueling gun is shut down
earlier than this, it shall be restarted to deliver fuel within 15 s. The refueling gun shall
comply with the provisions of I4.8.2 in the Appendix I of GB 18352.6-2016.
5.17.5 According to Appendix I of GB 18352.6-2016, conduct refueling emission test
and calculation.
6 Inspection rules
6.1 The product must pass the inspection of the manufacturer, before leaving the factory.
6.2 Product inspection is divided into exit-factory inspection and type inspection.
6.3 Exit-factory inspection
6.3.1 Full inspection items: Fuel tank appearance, fuel tank tightness.
6.3.2 Sampling inspection items include fuel tank capacity measurement, inner surface
cleanliness test, refueling test, angle hammer impact test, bursting test. Sampling
inspection methods are in accordance with the provisions in Table 1 of GB/T 2828.1-
6.4 Type inspection
6.4.1 The products for type inspection shall be selected from the products, that have
passed the exit-factory inspection; the sampling inspection method shall be in
accordance with the provisions in Table 1 of GB/T 2828.1-2012.
6.4.2 When one of the following situations occurs, carry out type inspection on the fuel
- When the new product is type finalized OR the original old product is transferred
to another production site;
- Changes in main design, process, materials, which may affect the performance of
the fuel tank;
- When there are large fluctuations in the exit-factory inspection results or large
differences from the previous type inspection;
- When the production is resumed, after suspension for 1 year or more;
- When the national quality supervision agency requests type inspection.
6.4.3 Type inspection items are all items specified in Chapter 5.
7 Signs, packaging, transportation, storage
7.1 Signs
Products and packaging shall have signs; the content of the signs shall include product
name, product model, trademark, manufacturer name, factory address, date of exit-
factory, etc. The product shall be accompanied by a product certificate and a 3C sign,
which is approved by the national certification authority.
7.2 Packaging
The products sent to the assembly line of the vehicle factory shall be packaged
according to the customer's requirements; other products sold shall have appropriate
packaging; the fuel tank shall not be squeezed, bumped, deformed in the transportation
The interface between the fuel tank and the outside shall be subject to the treatment of
dust prevention.
7.3 Transportation
The fuel tank shall be protected from bumps, scratches, extrusion deformation during
7.4 Storage
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.