LPG

LPG (Liquefied Petroleum Gas) is a hydrocarbon fuel mixture primarily composed of propane and butane. At ambient temperature and atmospheric pressure, it exists in a gaseous state, but readily condenses into liquid form for storage under moderate pressure or refrigeration. As a clean-burning and efficient fossil fuel, LPG has long been widely utilized across industrial applications, domestic cooking, commercial heating, and as an alternative automotive fuel. In vehicular powertrain applications, LPG serves as a cleaner substitute for conventional petrol and diesel, powering internal combustion engines via retrofitted or factory-fitted bi-fuel systems. Thanks to its lower tailpipe carbon emissions and negligible particulate matter, LPG has achieved widespread adoption across public transport fleets and passenger vehicles in numerous automotive markets worldwide.

Core Technical Architecture and Fuel Delivery System

The technical architecture of an automotive LPG system primarily comprises a high-pressure gas cylinder, a multi-valve safety assembly, high-pressure fuel lines, an LPG reducer/vaporiser, and a dedicated electronic fuel injection system:

High-Pressure Liquid Storage and Multi-Function Safety Valve Assemblies: 

Vehicular LPG is typically stored in liquid form within dedicated high-pressure steel or composite cylinders (operating at working pressures between 1.0 and 2.0 MPa). Each tank is fitted with a precision multi-valve safety assembly integrating an automatic excess flow check valve, an 80% automatic fill limiter, a pressure relief valve, and a manual service valve, ensuring controlled pressure venting and preventing catastrophic ruptures during severe collisions or extreme thermal exposure.

Vapourisation Pressure Regulation and Dedicated Electronic Fuel Injection:

Liquid LPG from the storage tank is channelled via high-pressure fuel lines into the reducer/vaporiser located in the engine bay. Utilising waste heat from the engine coolant, the unit rapidly vaporises the liquid fuel into a gaseous state while regulating its delivery pressure within a precise operating range. The gaseous LPG is then metered and injected on demand into the intake manifold or combustion chambers via dedicated electronic gas injectors (with select modern systems utilising direct liquid injection), mixing with air before ignition to generate power.

Safety Regulations and Physical Limitations

Strict Prohibition of Refuelling in Underground Car Parks, Enclosed Spaces, or Near Open Flames, and Prohibition of Engine Cranking During Leaks: 

LPG vapour is heavier than air, meaning any leakage will rapidly settle and accumulate in low-lying areas or at ground level. Refuelling is strictly prohibited in poorly ventilated enclosed spaces or near open flame hazards. Attempting to start or crank the engine upon detecting the distinctive pungent odour (from added chemical odorants) or confirmed fuel line leaks is strictly forbidden, as any stray ignition source can trigger a flash fire or explosion.

Strict Prohibition of Non-Certified LPG Cylinder Retrofits, Over-Age Cylinder Use, or Evading Mandatory Periodic Inspections:

Automotive high-pressure storage tanks are classified as critical pressure vessels, governed by stringent statutory standards regarding material fatigue resistance and burst pressure thresholds. Retrofitting sub-standard, non-certified fuel tanks, operating cylinders past their certified service life, or skipping mandatory periodic safety inspections is strictly prohibited. Aged or structurally compromised pressure tanks present severe safety hazards; strict compliance with national and regional automotive regulatory frameworks is mandatory.