What is the difference between OEM factory-fitted CNG and retro-fitted CNG kits?
OEM (Original Equipment Manufacturer) factory-fitted CNG means the vehicle manufacturer installs the CNG system during production – examples include Maruti Suzuki's factory CNG variants (WagonR CNG, Swift CNG, Dzire CNG), Hyundai's Aura CNG, and Tata's Tiago CNG. Factory CNG systems use OEM-engineered components, are integrated with the vehicle's ECU from manufacture, carry full OEM warranty, and require no RTO endorsement (already registered as CNG from factory). Retro-fitted CNG uses an ARAI/iCAT-approved aftermarket kit installed post-purchase – it is legally permitted but requires PESO-authorised installation and RTO RC endorsement. Factory CNG is generally preferred for new vehicle buyers; retro-fitment is the option for existing petrol vehicle owners wanting CNG economics.
What is PESO and why is its authorisation mandatory for CNG installation?
PESO (Petroleum and Explosives Safety Organisation) is the statutory authority under the Explosives Act 1884 and Petroleum Act 1934, responsible for regulating the safe handling, storage, and use of petroleum products and explosives in India. CNG is classified as a compressed flammable gas and its installation in vehicles falls under PESO's jurisdiction. PESO authorisation for CNG vehicle kit installation workshops is mandatory because: CNG at 200 bar pressure is an inherently dangerous substance; improper installation can cause fatal explosions or fires; PESO-authorised installers have demonstrated compliance with safety standards including workshop fire safety, trained technician certification, proper tooling, and leak testing protocols. Installing without PESO authorisation is a criminal offence under the Petroleum Act carrying imprisonment and fines.
What is the mandatory hydrostatic testing interval for CNG cylinders and what happens if I miss it?
CNG cylinders in India must undergo hydrostatic pressure testing every 3 years (from the date of the previous test) under PESO regulations and CMVR Rule 115A. Cylinders that have reached 15 years from their manufacture date must be permanently decommissioned regardless of test history. During a hydrostatic test, the cylinder is pressurised to 1.5x its operating pressure (300 bar) to detect wall weakness, cracking, or corrosion. If you miss the testing interval: your CNG vehicle is legally non-compliant and cannot be driven; your motor insurance policy is void (most policies exclude CNG incidents for non-compliant cylinders); traffic police can seize the vehicle; and most critically – you are driving with a potentially dangerous cylinder. Vehicle owners should check the test due date stamped on their cylinder and schedule testing at least 30 days before the due date.
Will installing an aftermarket CNG kit void my vehicle's OEM warranty?
Technically, an ARAI/iCAT-approved CNG kit installed by a PESO-authorised installer does not automatically void your OEM warranty. Under consumer protection principles, an OEM can only void warranty for a specific component if it can demonstrate that the CNG installation caused the failure of that component. However, in practice: engine-related warranty claims post-CNG installation can be disputed by OEMs who may claim the CNG operation contributed to the failure; some OEMs explicitly state in their warranty policy that retro-fitment voids engine warranty. Recommendation: if your vehicle is under OEM warranty, consult your authorised dealer about their specific warranty policy before CNG retro-fitment; consider factory CNG variants for new vehicle purchases; for out-of-warranty vehicles, proceed with ARAI-approved retro-fitment without concern.
What is a sequential CNG injection system and why is it required for modern cars?
A sequential CNG injection (SCI) system delivers metered quantities of CNG gas directly into each cylinder's intake port in precise synchronisation with the engine's firing sequence – exactly mirroring how the original petrol multi-point fuel injection (MPFI) system operates. This is essential for modern BS-VI engines because: BS-VI engines have precise stoichiometric control requirements (air:fuel ratio 14.7:1) that only sequential injection can maintain; older non-sequential 'venturi' or 'mixer' systems introduce gas upstream of all cylinders simultaneously – causing mixture imbalance, rough running, increased emissions, catalytic converter damage, and OBD-II fault codes. Under the CMVR and BS-VI regulations, only sequential CNG systems are approved for retro-fitment on modern MPFI engines. Any installer proposing a venturi/mixer system for your 2017+ model petrol car is proposing an illegal, non-ARAI-approved solution.
