Propane Fuel Systems Presented by K Kubota Engine America

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Propane Fuel Systems
Presented by K Kubota Engine America and Kubota
Canada Ltd
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Characteristics of Propane

• Also known as LPG, Liquified Petroleum Gas.
• LPG is heavier than air.
• LPG is a by-product of oil and natural gas
  refining.
• 1USgallon (3.79L) of LPG will create 272USgallons
  (1030L) of gas.

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Characteristics of Propanecont..

• 1USgal. (3.79L) of LPG at 24 1 ratio will
  create 1300ft3 (36.8m3) or 10,000USgal. (37854L)
  of combustible gas.
• In its liquid state it will boil at 44oF.(-42oC)
• LPG ignites between 957oF (514oC) to 1090oF
  (588oC). Gasoline ignites at approx. 780oF
  (416oC).
• LPG is a colorless and odorless gas. The odor is
  added for safety.

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Propane Safety

• LPG is a highly flammable fuel contained under
  pressure and may cause fires and/or explosions if
  improperly used.
• LPG in its liquid state (-44oF / 42oC) can
  freeze skin.
• When possible, turn off the LPG fuel supply and
  run the engine until it runs out of fuel.

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Propane Safety
Cont..

• Perform repairs in a well ventilated area.
• Use only approved fittings and line.
• Leak check all fittings, lines, and joints after
  repair.
• Always front seat or back seat the main supply
  valve.
• Never check for leaks with a flame.

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Benefits of Propane

• Clean Burning.
• Longer Engine Life.
• Reduced Emissions.
• Higher Octane (112).
• Easily Transported and Stored.
• Non Poisonous.
• Will Evaporate quickly if spilled.

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Basic Propane System

• Pressure Tank
• Shut Off Valve
• Filter
• Electric Shut Off Valve
• Vaporizer
• Carburetor / Mixer
• Engine

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Manual valve
lt0Kg/cm²
Minimum operating pressure 0.35Kg/cm²
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Propane Vaporizer

• Primary Chamber. Liquid fuel is decompressed and
  evaporated.
• Secondary Chamber. Decompresses gas to
  approximately atmospheric pressure.
• Water Passage. The engine coolant is used to
  supply heat to evaporate the LPG.
• Vacuum Lock Chamber. Locks fuel in the primary
  chamber when engine is off.
• Not Field Serviceable.

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Vaporizer
Water Passage
Secondary Chamber
Primary Chamber
Vacuum Lock Chamber
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Primary Chamber
Primary Chamber
Primary Diaphragm Spring
Primary Valve Lever Spring
Primary Diaphragm
Primary Lever
Primary Valve and Seat
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Secondary Chamber
Secondary Valve and Seat
Secondary Lever Spring
Secondary Valve Lever
Secondary Diaphragm
Diaphragm Pin
Balance Spring
Atmosphere Chamber
Secondary Chamber
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Vacuum Lock Chamber
Primary Chamber
Vacuum Lock Diaphragm
Diaphragm Spring
Vacuum Lock Chamber
Secondary Chamber
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Carburetor and Mixer

• Throttling Device.
• Creates Pressure Differential.
• Blends Air and Fuel.
• Multiple Fuel Capability.
• Gasoline and LPG Valves are Normally Closed.
• Shuts Off Fuel.

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Gasoline Mode
Venturi Effect
Float
Gasoline
Solenoid Energized
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LPG Mode
Solenoid Energized
Venturi Effect
From Vaporizer
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Mixer
Throttle Plate
Venturi Effect
LPG Main Jet
Gaseous Propane from Vaporizer
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Propane Installation

• Vaporizer must be mounted vertically.
• Gaseous line must be 300mm /- 20mm in length.
  (11.8/-.8)
• Vaporizer, air needs to be bled from water jacket
  after installation.
• All lines must be routed and secured to avoid
  chaffing.
• Vaporizer must be isolated from vibration.

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Propane Troubleshooting

• Low Power
• Shut Off Valves Fully Open.
• Look for Frost.
• Check Vacuum Line for Cracks or Restrictions.
• Restricted Coolant Lines to Vaporizer.
• Atmosphere Port Blocked.

• No Start
• Fuel available.
• Power to Solenoids.
• Vacuum Source at Vaporizer. 4(102mm) minimum.
• Flooded. Disconnect vacuum line or unplug
  solenoid to clear.
• Look for Frost.
• Throttle Plate Closed.

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Propane Troubleshooting
Cont..

• Engine Dies
• Fuel Available.
• Look for Frost.
• Coolant to Vaporizer.
• Power to Solenoids.
• Vacuum to Vaporizer.
• Atmosphere Port Blocked.

• Engine Runs Rich
• Ruptured Primary or Vacuum Lock Diaphragm.
• Air Filter.
• Gasoline Solenoid not Closing Properly.
• Vaporizer Valves not Seating Properly.