What is Auto-LPG?

  • LPG is a generic name for mixtures of hydrocarbons (mainly propane and butane) which exists as vapour under ambient conditions and can be changed into liquid state by application of moderate pressure.
  • Typical composition of Auto-LPG is 30-40% propane and 60-70% butane and inherently has clean burning characteristics.

Describe the Auto-LPG Conversion Kit

  • Conversion from a gasoline engine to LPG requires presence of a qualified technician. Under a dual fuel system all gasoline parts are retained as the system allows one to start and run the vehicle with either LPG or gasoline with the help of a change over switch per guideline by qualified technicians.

Important Features of the Auto-LPG Dual System

  1. Tank - contains the LPG with capacity ranging from 30 to 100 liters.
  2. Multivalve - facilities refuelling, has an 80% stop-fill safety device that acts as a shut-off valve in the event of the rupture of LPG line.
  3. LPG Solenoid Valve - allows entry as well as prevents flow of LPG to the system; depending on the mode selected.
  4. Gasoline Solenoid Valve - allows entry as it prevents flow of gasoline to the system; depends on the mode selected.
  5. Electronic Control Module - regulates the flow of LPG depending on the engine RPM (only in fuel injected models.
  6. Gas/Petrol Switch - allows change over from gasoline to LPG.
  7. Pressure Regulator on Vaporizer - facilitates vaporization of LPG from liquid state.
  8. Mixer or Gas Injection - introduces the vaporized LPG in the combustion chamber.

Frequently Asked Questions About Auto-LPG

  1. Q: What motor types can be converted to LPG?
    A: All gasoline-fed automobile and motorcycle engine.
  2. Q:How long does it take to convert to Auto-LPG system?
    A:Depends on the engine condition but generally the engine must be in good running condition and the cooling system functioning well. Conversion process usually takes only 2 days or less.
  3. Q:Does the speed and performace change?
    A:Older LPG conversion kits resulted in a decrease in performance by 5% on a higher rpms but for the newer electronic injection systems, there is no noticeable change in performance compared to gasoline.
  4. Q:What is a dual fuel system?
    A:This system enables one to start and run the vehicle with either gasoline or LPG by using an electronic change over switch provided on the dashboard of the vehicle. The vehicle can be started on either fuel and there is no difference to the normal operation of the car.
Sources: Shell website and Petron facts on Auto Gasul

SAFETY TIPS: Auto-LPG Fuelled Vehicles (Dos and Don'ts)


  1. Never assume the fuel system is free from LPG. Isolating the fuel tank and running the engine until it stops will ensure that the system is gas free.
  2. Don't carry out-welding, burning and other hot works on an LPG vehicle within 1 meter of its tank on fuel lines without a heat resistant shield or before the parts have been emptied or gas freed.
  3. Never undertake roadside repairs unless workers are trained and approved safe equipment are available in the site.
  4. Don't crush a vehicle until the LPG tank has been removed by a competent person.
  5. LPG vehicles due for scrapping or recycling should not be accepted unless procedure for safe removal and disposal of LPG system are in place.


  1. Ensure to deploy only trained and competent workers in LPG fuelled vehicle related jobs.
  2. Follow the vehicle manufacturers on system installers' instructions and make sure workers are aware of locations of LPG tank and fuel lines.
  3. When working on open spaces, ensure safe places for parking and working on vehicles, e.g. away from drains, pits and other openings in the ground and all sources of ignition.
  4. Empty fuel lines to the engines by isolating fuel tank and running the engine until it stops.
  5. Wear protective equipment (PPE) to prevent cold burns, eye damage and discharge of static electricity those who may be carrying out hot work.
  6. Carry out roadside check for leaks and other damages to the LPG system on vehicles involved in accidents.

In addition, observe the following safety precautions in case of incidence of a leaking LPG system in a service station while filling and while on the road

  • Switch off the LPG pump by activating the "Emergency Switch" of the dispenser.
  • Quickly disconnect the dispenser's nozzle from the filler valve of the vehicle and return to the dispenser's nozzle holder.
  • Close all the valves of the liquid and vapor LPG line of the LPG storage tanks, including the valves in the pipelines. (Where applicable, activate the "Automatic shut-off valve" for the main liquid withdrawal from the tank).
  • Simultaneous with the above, close the valves for the liquid and vapor line located under the dispenser.
  • Move all vehicles or any source of sparks away from the leaking portion of the system.
  • Allow complete but controlled release of all trapped LPG from the tubings on the affected portion of the system.
  • Leak test the affected portion ensuring it's already free from leaks. In the absence of a gas detector, use soap and water solution.
  • Let a qualified contractor do the repairs.
Sources: UK HSE Publication courtesy of LiquiGaz Phils. & Petron Corporation
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