Question: Hi, I am thinking to convert my petrol car to CNG fuel. What is expert advice on fuel conversion kits available in the market ? What are the Do's and Don'ts for this kind of conversion ? Is it advisable if yes then what is the preferred fuel optin LPG or CNG ?
Answers: You can convert your petrol car to either CNG or LPG. .Please find below the pros and cons of fitting a CNG kit vis-à-vis an LPG kit. In CNG , more space is occupied in your dickey because of the CNG cylinder installed. But the LPG tank is more compact, leaving room for some luggage space in the boot. In a hatchback, this is a crucial difference. CNG tanks are much bigger and heavier than LPG tanks since the gas is compressed to a very high pressure unlike LPG which is in liquid form like petrol. A 12kg CNG tank filled with 10 kg gas weighs close to 100kgs. All that weight means the car will bottom out quite frequently, especially with 5 people on board. LPG kitted cars fare better in this respect. Since you have not specified about your location, please understand the CNG or LPG filling stations network in your city along with cost of CNG v/s LPG. In CNG cars, performance of the engine is a bit compromised unlike in a LPG kit fitted car the engine performance characteristics are not much affected. Different types of kits CNG and LPG kits come in three different packages: 1. Open loop: These are cheapest kits on CNG and LPG both. These are simple and mechanical, without any electronics. As the name suggests, it is an open loop. As CNG and LPG are clean gases, it really doesn’t affect pollution in the case of an open loop. 2. Closed loop: In a closed loop, the exhaust gases are inspected by the sensors and the volume of intake gas is monitored accordingly to minimize pollution. 3. Sequential injection: Sequential injection is the advanced version kit. The mechanism is exactly similar to the manner in which a normal fuel injection system works and the intakes are controlled by an engine control module or ECM. An ECM is a generic term for any embedded system that controls one or more of the electrical systems or subsystems in a motor vehicle. In short, the difference between a sequential kit and conventional one is same as that of multi-point fuel injection (MPFI) and carburetor, respectively. Different manufacturers of these kits Kits from various manufacturers are available in the market. Some are Indian, some Italian. The Italian ones have been used extensively in the market. Do’s & Don’ts : · It is recommended to run the vehicle on petrol mode for first 5~10 kms after every 300~500 km run in CNG mode to keep fuel system in good condition. · Always keep minimum 5 liters of petrol in your petrol tank · If the kits are factory fitted, fire extinguisher is fitted naturally. When you get your kit installed, ensure to fit your fire extinguisher accordingly. · When the pressure drops in the red zone area in the pressure gauge in fire extinguisher , immdtly contact the authorized service center for inspection & refilling. · Ensure that the Fire extinguisher is always kept at its prescribed position in the vehicle ( usually below the driver seat or co passenger seat ). · Refill the fire extinguisher immediately after use. · Fire extinguisher needs refilling after every 3 years even if it is not used. · Do not use water for cleaning fire extinguisher. (Use clean cloth for removing dust) · Do not rely on used or discharged fire extinguisher. · CNG cylinder leak testing and certification should be done every 5 years from the date of initial testing by govt. approved testing agency · CNG filler receptacle O-Ring to be replaced every 4 years or 300,000 Km, whichever comes earlier. · CNG is flammable keep away from fire. · In case of CNG leakage, stop vehicle and switch off the engine. · Close manual shut off valve on the top of CNG cylinder. · Do not run vehicle even in petrol. · Switch off the engine before refilling the CNG · Emergency Numbers : Police – 100, Fire – 101, Ambulance – 102. · The CN G cylinder should not be repaired under any circumstances. · Do not adjust the settings on the CNG system. · Never use LPG in CNG cylinder or vice versa. · Avoid carrying inflammable material near the cylinders. · Scrapping of LPG tank after expiry date : After emptying and purging of the tank it should be rendered unsuitable for further LPG service by · Mechanical crushing · Piercing holes · Cutting the body into two or more pieces · For mechanical crushing & piercing only pneumatic or hydraulic power should be used but not electrical tools. This has to be done by an authorized agency. · Once scrapped the parts may be recycled through the recycling/waste disposal system. · Expiry date is mentioned on the LPG LPG and CNG both help reduce your travel expenses by a great margin, but as you are investing and installing one of these kits, please ensure you get it done from an authorized dealer (for safety purposes). Remember you also have to keep the car for 2-3 years at least to recover the cost. Finally, based on the above we prefer CNG over LPG as it will be cheaper of the two to run and there are more CNG pumps than LPG ones. But you have to compromise engine performance, but that’s fine if your idea is cost-saving. But for those who still want performance like that of a petrol car, then the LPG kit is what we’d recommend.