There are currently two types of CNG kits available in the market and used in most automobiles. Those CNG kits are namely:
- Venturi CNG
- Sequential CNG
Venturi CNG Kits:
Sequential CNG Kits:
Difference between Venturi CNG kit and Sequential CNG kit:
- While the Venturi kits don’t have sensors or the Electronic Control Unit, the Sequential kits come with all kinds of sensors and an ECU for better control.
- The Venturi CNG kits cannot control the amount of CNG flowing into the engine whereas the Sequential CNG kits come with the ECU to monitor the flow of gas into the engine.
- Venturi kits are extremely easy to install as they don’t require an ECU or computer to control the gas flow. On the other hand, Sequential kits are a little more complex to install.
- While Venturi CNG kits can be installed on any type of vehicle, Sequential CNG kits can only be installed on vehicles that have an Electronic Fuel-Injection system.
Advantage of a Venturi-type CNG kit
Affordability is probably the biggest advantage of a Venturi CNG kit along with the easy installation process. There are no complicated procedures or complex wiring required when installing a Venturi-type kit. Because the Venturi kits do not require an ECU to install, they can be setup quickly and by anyone.
Disadvantage of a Venturi-type CNG kit
The biggest disadvantage of using a Venturi CNG kit is its unpredictability. Because a Venturi kit cannot control the flow of CNG into the engine, it pushes a fixed amount directly into the engine’s intake system. This irregularity causes a lot of stalling and pickup loss as well. Also, because of this, the kit and engine need frequent tuning and cleaning – something that requires a certain amount of expertise.
Advantage of Sequential kits
There are a number of advantages of using Sequential CNG kits but the biggest advantage is that you get better performance and mileage from your vehicle through a more controlled CNG injection. However, there is usually about a 15 percent drop in performance on account of CNG having lower combustibility and higher octane rating when compared to petrol. This means that CNG performs a lot better on high-compression vehicles rather than regular ones.
Disadvantage of sequential kits
Although there are relatively no long-term disadvantages of using a Sequential CNG kit, it is the initial cost of the kit that can be considered a disadvantage. Some brands of Sequential kits can cost up to more than two times of a regular Venturi CNG kit. The installation process is another small disadvantage as it requires modification and drilling adjustments to the engine’s intake manifold.
Open-Loop and Closed-Loop Sequential systems
If you are in the market for a Sequential CNG kit, you have to decide whether you want an Open-Loop or a Closed-Loop system. The difference between the two is that one uses the oxygen sensor installed in the vehicle’s exhaust to collect feedback and deliver it to the ECU and the other does not. While they are both perfectly fine to use on supported vehicles, they do come with their own advantages and disadvantages.
Closed-Loop System
Closed-Loop system Sequential CNG kits are definitely the more eco-friendly option as they use the Lambda sensor or Oxygen sensor that is placed in the exhaust of a vehicle to collect feedback and pass it on to the ECU. This sensor checks whether the emissions from the exhaust are in the permissible limits. Using this feedback, the ECU controls the flow of CNG gas into the engine and prevents excessive pollution.
Advantages
Thanks to better control over the flow of CNG gas into the engine, the Closed-Loop system offers greater fuel-efficiency. The injection of gas into the engine is always precise and optimal which, in turn, reduces emissions and helps keep the environment healthier.
Disadvantages
While the Closed-Loop system is great for the environment, it comes at a price – reduced performance. Because the ECU and the Lambda sensor work together to inject only the amount of gas required and reduce pollution, the vehicle will not have the same acceleration power a petrol engine can offer. This might be a major issue for those who are switching over from petrol-fueled vehicles to CNG-fueled ones.
Open-Loop System
Essentially the opposite of a Closed-Loop system, the Open-Loop system for a Sequential CNG kit is a system that does not use the Oxygen or Lambda sensor to collect feedback from the exhaust. This system lets drivers accelerate their vehicles as and when they need by injecting more gas into the engine as will.
Advantages
If the vehicles are older and do not have a Lambda or Oxygen sensor, it saves the vehicle owner’s money as they do not require one, something which costs an additional Rs 4,000 or so. Newer vehicles, however, do come with the Oxygen or Lambda sensor but if the owners do not connect the ECU to the sensor, it remains an Open-Looped system. Hence, the amount of CNG is not restricted into the engine and the pick-up and performance is better.
Disadvantages
The biggest disadvantage of an open-Loop Sequential CNG system is that it creates more exhaust emissions. Since there is no Lambda sensor to control the emissions, the vehicle can produce larger amounts when compared to Closed-Loop systems. Another disadvantage is that Open-Loop systems can cause damage to the engine and exhaust valves as they create a lot of heat inside the engine on an account of no CNG flow monitoring.
RTO Approved CNG Kit Brands in India
- Bedni
- BRC
- Bugatti
- Landi-Renzo
- Longas
- Lovato Autogas
- SKN
- Tartarini
- Tomasetto
- Unitax
- Zavoli
