cng

About CNG

CNG is mixture of hydrocarbons consisting mainly of methane gas (80 to 95%). It is compressed to a pressure of 200 bar for ease of storage in cylinders on vehicles.

CNG Gas at 200 bar pressure is filled into the CNG cylinders. The gas is dispensed in Kgs at CNG refueling stations.

On cranking the engine, High Pressure regulator’s solenoids are actuated. It  allows CNG Gas to pass from the CNG cylinders to downstream. A High pressure coalescing filter, fitted before pressure regulator, filters out oil & particles from the CNG gas before it enters the Pressure regulator. This filtering is necessary to avoid the damage caused to pressure regulator and injection system due to oil and particulate contaminations in the CNG gas.

After the HP filter, gas at 200 bar is passed into pressure regulator, which reduces the pressure of the gas from 200 bar to 7 bar. This pressure regulation process causes the temperature inside the pressure regulator to drop which may lead to freezing. To maintain this temperature and avoid ice formation inside the pressure regulator, hot coolant from engine is circulated through the pressure regulator.

CNG is then passed through a Low pressure hose into the common rail. The Gas is injected into the combustion chamber thro gas injectors which are controlled by the ECU based on the algorithms for various operating conditions.

 

General Precautions to be taken while Dismantling/working on CNG System:

1. Ensure no Spark, Cigarettes, Open flame near vehicle during dismantling of CNG System.

2. Ensure that working area is well ventilated.

3.  Always use personal protective equipments while removing & Refitment.

4. Ensure the Suitable fire extinguishers are available while working.

5. Close the Shut off Valve integrated with Cylinder Valve & Run the engine at idle till the CNG in the fuel lines is consumed. Once the CNG in the fuel lines consumed Engine will get cut off. After wait till it is cooled down.

6. Remove Battery Terminal.

7. While Removing Heating lines of HP Regulator (where required) use proper protective gloves. Spilt Coolant should always be wiped away immediately. Then start removal procedure of desired fuel system component.

CNG System- Do’s

1. Always Inspect joints etc. under pressure for leaks and proper installation after re-installation.

2. Ensure tubing is bottomed on Fitting body before re-tightening.

3. Always bleed gas from lines before servicing any CNG components.

4. Ensure that mating components threads are of same standards.

5. Always Inspect joints etc. under pressure for leaks and proper installation after re-installation.

6. Ensure tubing is bottomed on Fitting body before re-tightening.

7. Always bleed gas from lines before servicing any CNG components.

8. Ensure that mating components threads are of same standards.

CNG System- Don’ts

1. Never loosen any Component when system is pressurized.

2. Do not tighten taper threads without Teflon tape.

3. Do not over-tighten drain plug of filter after draining.

4. Do not put excessive weight or lean on tubing.

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