QC/T 245-2017Technical specifications for fuel gas systems of CNG vehicles (English PDF)

3.6 Leakage alarm device

A device installed on a gas vehicle and sends out an alarm when it detects a gas leakage or exceeding a preset value.

4.1 General requirements

4.1.1 The gas system shall be manufactured in accordance with product drawings and other technical documents approved by prescribed procedures.

4.1.2 The working environment temperature range that the gas system shall be able to adapt is as follows:

a) Installed in the engine compartment, -40 °C ~ 120 °C;

b) Install in other parts, -40 °C ~ 85 °C.

4.1.3 Parts of gas systems whose normal performance and safety functions are affected by CNG fuel characteristics, high pressure or vibration, need to comply with the relevant requirements of the corresponding parts standard.

4.1.4 The connection interface of gas system components shall meet the requirements of GB/T 3765 Specification for bite type tube fittings and other standards. The installation of gas system components on automobiles shall meet GB 7258 Safety specifications for power-driven vehicles operating on roads and GB 19239 Mounting requirements of special equipment for gas vehicle.

4.1.5 The components of gas system that are in contact with CNG shall be compatible with CNG. If the metal material used is ferrous metal, it shall take anticorrosive measures such as electroplating, chemical treatment or painting.

The coating and chemical treatment layer shall conform to QC/T 625.

4.1.6 It is not allowed to fill the vehicle with CNG by replacing the gas cylinder.

4.2 System requirements

4.2.1 The gas system shall include at least the following components.

k) Nozzle driver;

1) Ignition driver;

m) Oxygen sensor;

n) Camshaft (judging cylinder) phase sensor;

o) Emulator;

p) Speed sensor.

4.2.3 In one of the following situations, the gas system shall be able to automatically cut off the supply of CNG.

a) The ignition switch is not turned on;

b) The engine is not running;

c) CNG fuel pipeline breaks, falls off, etc.

4.3 Component requirements

4.3.1 Filling receptacle

At least one filling receptacle shall be installed on a CNG vehicle. The dust cover on the filling receptacle shall be easily fixed on the vehicle. The filling receptacle shall meet the requirements of GB/T 18363.

4.3.2 Gas cylinder

4.3.2.1 Steel gas cylinders shall comply with the provisions of GB 17258.

Metal linear fiber wrapped gas cylinder for compressed natural gas for vehicles shall comply with the provisions of GB 24160. The gas cylinders shall be equipped with accessories such as gas cylinder valves and gas cylinder safety valves. The gas cylinder valves shall meet the requirements of GB 17926.

4.3.2.2 If necessary, it should install the accessories such as airtight boxes and ventilation pipes.

4.3.3 Gas pressure (volume) display

The gas pressure (volume) display may use a pressure gauge or other gas volume display device. If a pressure gauge is used, the range of the pressure gauge shall be 1.5 ~ 3.0 times the rated working pressure of the gas storage system; it is recommended to use 2.0 times. When using other gas volume displays, it should use the pressure sensors and gas volume displays.