NANO VOLUME 1 & 2

FUEL SYSTEM

B. CYLINDER VALVE:

Function:

Cylinder valve is an electronically and manually

controlled shut-off valve fitted on the cylinder which

can open or shut-off the CNG supply and which

incorporates a bust disc and a fusible material. The

main function of this valve is to shut off gas flow from

the cylinder in to the system when the ignition of the

vehicle is off. Cylinder valve comes with 12 volts

solenoid coil. It is normally closed and activates only

when electric current is passed through the coil. The

solenoid coil / valve is an added safety feature.

In addition, Cylinder valve comes with 3 inbuilt safety

features, namely an excess flow device, a burst disc

and a fusible plug. These safety devices provide

protection in case of line rupture, over pressure and

fire. The burst disc and the fusible plug are pressure

relief devices (P.R.D.) which operate independently.

Constructional details:

The Cylinder valve consists of following

components.

Excess flow device:

This is an inbuilt safety device

which activates on excessive increase of the flow

rate of gas.

Burst Disc:

This is a pressure relief device which

activates in case of excessive increase of gas

pressure in the tank.

Fusible plug:

Fusible plug is also a pressure relief

device. This is thermal activated in case of excessive

rise in temperature near the valve.

Solenoid coil / Valve:

Solenoid coil is connected

with the ignition circuit of the vehicle. It is normally

closed and activates only when an electric current is

passed through the coil and there by it opens the

path for gas to flow freely into the high pressure line.

The solenoid coil is operated by CNG

ECU.If

any

leakage is observed by the CNG ECU in high

pressure line, it will automatically shut-off the

cylinder valve and stops the supply of CNG. When

the solenoid valve is closed, the gas can be filled into

the cylinder but cannot be withdrawn from the

cylinder.

Vent tube / Ventilation hose:

Vent tube is used for

the ventilation purpose so that when there is any

leakage through cylinder valve, the gas is vented out

of the passenger cabin in to the atmosphere.

Ventilation hose covers the entire length of ¼”

stainless steel tube in passenger compartment.

Mounting location:

The cylinder valve is fitted to CNG cylinder which is

located under driver & co-driver seat.

Manual ON / OFF Knob or Tap:

Cylinder valve is an automatic valve but a manual

knob is also provided as an additional safety for the

opening and closing the path of the gas.

This manual tap is normally kept open and it can be

closed at the time of maintenance / service or in

case of leakages.

The Knob should always be in open position to allow

the flow of CNG to Engine. In the close position of

the knob, CNG supply to the engine is stopped. Also

gas cannot be filled into the cylinder at knob closed

position. If the cylinder subjected to impact or fire

damage, it should be inspected and retested. On top

of the manual knob of the valve, the opening and

closing directions are clearly marked for the operator

to have a visual indication of the direction for

opening and closing.

To open the valve, the knob must be turned in the

anti-clockwise direction and to close, the knob must

be turned in the clockwise direction.