Tuesday, April 3, 2012

Type of CNG

Open Loop system

Basic Throttle Body Delivery system

Uses an Timing Advancer System if installed- Helps in Sudden Accelaration. Open Loop system is a Basic system with minimal requirements, However needs regular tuning and mandatory periodic checks. Open Loop system does not auto correct the Lamda readings( O2 in Emmision as scanned by Car OEM O2 Sensor Lamda) this leads to Check Engine light at times when the Mixture is Poor or Rich.

Cheaper Option- Starts at Rs 33,000 Avg + Timing Advancer for 2000 more.

Closed Loop System

Uses a Lamda Controller to regulate the flow of Gas into the manifold by Throttle Body Delivery ( Stepper Motor),by reading the O2 emissions. It Auto corrects the Mixture for Lean Mix and also emmulates the Reading to the ECU incase of any variations to avoid Check Engine Error- The Range is defined and not extreme.

Closed Loop system also has a RPM Cap regulated by Engine Power- Like all Systems the CNG mode clicks auto on RPM above 1500 or as set. In a closed Loop system it allows the engine to stay on CNG till about 4000 RPM and anything more it shifts to Petrol for the power needed at that level and on lowering down Auto shifts to CNG.

This ensure a better and Optimal Engine Power Management as desired at Higher Speeds.

Usually does not need regular checks, however as all kits needs periodic checks with Scanner to set/read the settings.

Does not need Timing Advancer.

Usual costs are around Rs 40,000 onwards.

Sequential CNG systems

Similar to the Closed loop, However has a seprate ECU to manage all Gas functions- The main feature is that it incorporates an Injection Rail System with seprate Injectors - Auto mixing the Air-CNG in the right mix.

Sequential Systems are advanced an good, But they are pretty expensive and replacement costs are higher since not all locations and dealers can service this kind of setup.

Major issue is that it needs disconnection of the OEM petrol MPFI injector setup

Sequential Kits are as of yet pending approval from ARAI for use in Indian BS 3 Stage cars.

Needs a Pro to install, Avg costs are Rs 65,000 Upwards.