Is alternative fuels gain popularity among car owners looking to cut costs and reduce emissions, a common question arises: Can I put LPG in a CNG car?
This query, along with concerns about fuel prices, mileage, safety, and conversion feasibility,
has become a top priority for those using or considering compressed natural gas (CNG) or liquefied petroleum gas (LPG) vehicles.
Below, we break down the answers to these critical questions to help you make informed decisions.
Can LPG Be Used in CNG Cars? The Short Answer: No
First and foremost, you cannot simply put LPG in a CNG car—and attempting to do so poses serious risks. CNG and LPG systems are engineered for fuels with vastly different properties,
and their components are not interchangeable.
CNG is stored as a high-pressure gas (around 200 bar) in thick, cylindrical tanks designed to withstand extreme pressure.
Its delivery system relies on regulators that reduce this high pressure to a level safe for engine combustion, along with specialized injectors calibrated for methane (the main component of CNG).
LPG, by contrast, is stored as a liquid under low pressure (about 8 bar at room temperature) in lighter, tank-style containers.
It requires a vaporizer to convert liquid LPG into gas before it enters the engine, and its injectors are tuned for propane/butane blends (the primary components of LPG).
Mixing the two fuels would damage the fuel system—for example, LPG’s liquid form could corrode CNG’s high-pressure lines,
or CNG’s low calorific value could cause incomplete combustion in an LPG-calibrated engine. Worse, it could lead to leaks, engine misfires, or even fires.
Which Is Cheaper: LPG or CNG? CNG Takes the Lead on Cost
For budget-conscious owners, fuel price is a major factor. Globally, CNG is almost always cheaper per unit of energy than LPG, though prices vary by region.
How Much Can a Car Run on 1 kg of CNG? Mileage Varies by Vehicle
CNG’s mileage depends on factors like the car’s make, engine size, and driving conditions (city vs. highway).
If you own an LPG car and want to switch to CNG, conversion is possible—but it’s not a simple swap.
It’s critical to choose a certified installer—unapproved conversions can void your car’s warranty and pose safety risks.
Is LPG Safer Than CNG? Both Are Safe, But Risks Differ
Safety is a top concern for alternative fuel users, and both LPG and CNG are considered safe when properly installed and maintained—though their risks differ.
CNG risks: Because it’s stored at extremely high pressure, a damaged CNG cylinder could leak gas rapidly. However,
CNG cylinders are built with thick steel or composite materials (resistant to impacts) and include safety valves that release gas slowly if pressure spikes.
CNG is also lighter than air—if it leaks, it rises and disperses quickly, reducing the risk of pooling (which can cause explosions).
LPG risks: LPG is stored as a liquid under low pressure, so leaks are more likely to form pools (since LPG is heavier than air).
These pools can ignite if they come into contact with a spark. LPG tanks are also lighter than CNG cylinders, but they include overflow valves to prevent liquid leaks.
In short, neither fuel is “safer” overall—safety depends on proper installation.
