CNG Kit in India: Price, Function, Conversion

It is evident that carmakers and governments are actively promoting electric cars and the number of electric cars in the market is increasing. However, the push towards EVs is not proportionate to their sales figures. At the same time, what does not get highlighted enough is that the sales of CNG-powered cars have dramatically increased in the past few years. In addition to that, there are numerous people who make their cars CNG-compliant by having them retrofitted with aftermarket CNG kits. This is how a lot of consumers have chosen to cope with rising fuel prices and keep running costs of their cars as low as possible. If you are one such individual and want a car equipped with a CNG kit or are looking to have an aftermarket CNG kit installed in your car, here is everything you need to know about CNG kits, their functioning, and prices.

What is a CNG Kit?

While this does not apply to all engines, many internal combustion engines, including both petrol and diesel engines, can run on CNG (Compressed Natural Gas). A CNG kit is a system that converts a petrol or a diesel car into a CNG car. What comes as an added benefit is the option to switch between CNG and normal fuel. Many cars in India come with factory-fitted CNG kits,  such as the Maruti Wagon R, Maruti Swift, Hyundai Grand i10 Nios, Tata Tiago, Tata Punch, and Tata Nexon. All the same, many choose to buy a car with a regular internal combustion engine and then retrofit aftermarket CNG kits in their cars. It is important to know that you need a legitimate permit from your local RTO to install a CNG kit in your car.

A CNG kit consists of:

• Electric Control Unit (ECU): ECU controls the flow of CNG into the engine. They either install a new ECU or recalibrate the one in use.
• Pressure gauge: The pressure gauge detects the pressure of the CNG in the cylinder and makes sure the cylinder is in complete sync with the fuel injection system.
• Refill valve: The valve from where CNG is refilled.
• High-pressure tubes: Built to contain high-pressure gas, these tubes carry CNG throughout the setup.
• CNG tank: The tank where the CNG is stored in the vehicle.
• Clamps: These clamps hold the pipes intact in their positions as CNG flows through them.
• Regulator: The regulator stops the flow of gas if the pressure is too high.

Types of CNG Kits

If you want to have a CNG kit installed in your car, it would pay dividends to learn about the types of CNG kits available in the market.

Venturi CNG Kits

Venturi CNG kits can be installed in any vehicle, especially cars with carburetors. With the Venturi CNG kit, CNG is directly pumped into the engine in a fixed volume, depending on the throttle input. Because they work like carburettors, Venturi CNG kits are simple in construction, easy to install, and relatively affordable. A key benefit of the Venturi kit is that it does not require the ECU to be recalibrated or a new one. However, it requires more maintenance and frequent cleaning because it does not have adequate control over the volume of CNG flow into the engine. This also results in slow acceleration and occasional stalling of the engine. Despite its affordability, the Venturi CNG kit incurs higher maintenance costs over time due to its limitations.

Sequential CNG Kits

Sequential CNG kits are designed for vehicles with fuel injection systems, which precisely control fuel delivery for better efficiency. This is why with a sequential CNG kit, either the car’s ECU is required to be remapped or a new one is needed to be installed. Due to the ECU, the sequential CNG kit is better able to monitor and control the CNG flow into the engine and consequently delivers better fuel efficiency. Given the inclusion of an ECU, the sequential CNG kit is more expensive compared to the Venturi CNG kit, however, it is still considered the better option. The sequential CNG kits are of two types: closed loop system and open loop system.

Closed Loop System

The closed loop system is aimed to keep the flow of CNG within optimum limits. For this purpose, it comes with Oxygen sensors, also known as Lambda sensors. These sensors are installed in the exhaust system and monitor the emissions. While monitoring the emissions, they send the feedback to the ECU, which then controls the CNG flow to minimise the harmful emissions, keeping the vehicle’s pollution in check. Due to such functioning, the closed loop systems play a key role in cutting down the air pollution and because the CNG is injected into the engine in optimum volumes, this system also delivers better fuel efficiency. At the same time, the closed-loop system with its well-monitored CNG consumption, slows the acceleration and it lacks the instant thrill that driving enthusiasts like when they press the accelerator.

Open Loop System

The open loop system is the one without any Oxygen or Lambda sensors in the exhaust system. Thereby, the flow of CNG into the engine is not dependent on the emission levels. This results in better acceleration and those who want better pick-up and performance prefer this system. Moreover, since there are no Lambda sensors in this system, it is relatively more affordable. At the same time, this is not the system for those who want good fuel efficiency and due to unchecked and increased emission levels, this system is not good for the environment-friendliness of the vehicle. What is an even more significant disadvantage, is that more emission may cause heating issues, which eventually damage the exhaust valves.

Difference between Venturi CNG Kit & Sequential CNG Kit

Here are the key differences between the Venturi CNG kit and the Sequential CNG kit.

How is a CNG Kit installed in a car?

Installing a CNG kit in a car is a difficult process and should only be done by a professional. It is strongly recommended to not carry out the process by yourself and if you want to, do it with the help of an expert. To install a CNG kit in your car, you need an air/gas mixer, pressure regulator, high-pressure line, CNG filling valve, CNG tank, manometer, selector switch (to swap between petrol and CNG), emulator, and heat maintenance system. Once these parts are installed at their designated places, the car becomes compatible with the CNG fuel type, however, the work is only partially done. After installing the parts, ensure all parts are correctly placed and tightened. Check the pipes and pressure regulator for leaks. Once you are sure that there is no leakage and every part is correctly installed, start the engine in petrol mode and after some time, switch to the CNG mode.  

What to keep in mind when installing a CNG Kit?

Before installing a CNG kit in your car, it is vital to consider a few key aspects of this transition. Here are some key factors you should keep in mind before converting a regular car to a CNG-powered car.

Compatibility

OEMs that sell CNG-powered cars, like Maruti Suzuki, Tata Motors, and Hyundai offer warranties on the CNG kits they install in their cars. However, aftermarket CNG kits do not come with comprehensive warranties and their cost depends upon their quality. This is why it is vital to do thorough research to find out the most suitable CNG kit for your car and decide if you want to install an aftermarket CNG kit. This generally depends on the engine and fuel type of your car. Many cars are not compatible with CNG kits at all, especially older cars. If you want to know if your car is compatible with aftermarket installation of CNG kits, you can visit your local RTO as they keep a list of CNG-compatible cars.

Legitimacy

Along with keeping the list of CNG-compatible cars, RTOs also approve and disapprove aftermarket CNG kits. There are many unapproved and counterfeit CNG kits available in the market, and as a responsible individual you must check the quality of the CNG kit they want to purchase and whether or not it is approved by the local RTO.

At the same time, to convert your car to a CNG-compatible car, you will need to get permission from the authorities at the local RTO. For this, you will need to submit a formal request to the RTO and once they approve the conversion, the RC of your vehicle will be updated and in that, instead of petrol or diesel, CNG will be mentioned as the fuel type of your vehicle.

Informing the insurance provider

In addition to taking RTO’s approval, you also need to inform the insurance provider of your car about the fuel type conversion of your car. If you fail to do so, they will reject any claim in case of the settlement. You should not wait for insurance renewal to inform the insurance provider and let them know as soon as you install the CNG kit in your car. Moreover, installing a CNG kit in your car will increase the premium by nearly 10 percent.

Availability

Before installing a CNG kit in your car, you must check if there are enough CNG pump stations in your area or nearby your area. While CNG cars have been in the market for a long time, however, there are still far fewer CNG pump stations across the nation compared to the number of petrol and diesel pump stations.

Impact on the long-term performance of the engine

Cars that come with factory-fitted CNG kits are tuned precisely for the CNG fuel type. The same is not the case when an aftermarket CNG kit is installed in an ICE car. Because, in ICE cars, along with powering the vehicle, the fuel also plays the role of a lubricant for valves and the cylinders of the engine. However, in CNG cars, CNG cannot lubricate the valves and cylinders, making them more susceptible to corrosion and reducing their life. This is why the performance of cars with retrofitted CNG kits decreases over time.

CNG kit maintenance

ICE engines are primarily developed to operate on petrol or diesel. When their functionality changes to work with CNG, their maintenance requirements also change. While CNG cars are also serviced from time to time at service centres, here are some tips that will help you maintain your CNG-powered car properly.

• Air Filter: In CNG-powered cars, the air filters must be cleaned at every six months or 5,000 km and replaced after every twelve months or 10,000 km.
• Spark Plugs: The spark plugs must be replaced every 40,000 km and cleaned after every 12 months.
• Throttle Body: The throttle body – the connector of the air filter and intake manifold should be cleaned every 10,000 km.
• CNG Reducer and Low-pressure Filter Cartridge: The CNG reducer reduces the pressure of the CNG coming from the CNG tank and the low-pressure filter cartridge cleans the CNG of any contaminants. The CNG reducer should be replaced every 40,000 km, whereas the low-pressure filter cartridge should be replaced every 20,000 km.
• CNG Cylinder: The CNG cylinder must be checked regularly with hydro testing, which checks the cylinder for leaks, corrosion, and any other damages.

Summary

CNG cars are a wise way to cope with rising fuel prices, and this also explains why the sales of CNG cars have dramatically increased in the last few years. However, many choose to make their cars CNG-compatible by installing aftermarket CNG kits. To help such folks, this article explains everything needed to know about the aftermarket CNG kits, types of CNG kits, how a CNG kit can be installed in a car, and what things to keep in mind before you decide to install a CNG kit in a car.

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