CLARK FORKLIFT IC 101 Fuel System TECHNICAL TRAINING MANUAL

IC 101 Fuel System.s

TECHNICAL TRAINING Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Contents About this Class................................................................................................

About Safety.....................................................................................................

Section 1. IMPCO LPG Fuel System..............................................................

Engine Used..........................................................................................

Characteristics of LPG..........................................................................

Fuel Used: HD-5 Propane....................................................................

Function of Basic IMPCO LPG Fuel System.......................................

Components of Basic IMPCO LPG Fuel System.................................

LPG Tank..............................................................................................

LPG Lines..............................................................................................

Hydrostatic Relief Valve.......................................................................

Vacuum Lines........................................................................................

Water Lines...........................................................................................

Fuel Lock-OffValve and Filter.............................................................

Vaporizer-Regulator..............................................................................

Carburetor.............................................................................................

Governor................................................................................................

Maintenance of Basic IMPCO LPG Fuel System................................

LPG Tank..............................................................................................

LPG Lines..............................................................................................

Hydrostatic Relief Valve.......................................................................

Vacuum Lines........................................................................................

Coolant Lines.........................................................................................

Fuel Lock-OffValve and Filter.............................................................

Vaporizer Regulator..............................................................................

Carburetor.............................................................................................

Throttle Linkage...................................................................................

Carburator Adjustment.......................................................................

Governor Adjustment............................................................................

Troubleshooting.....................................................................................

Basic Checks Before Troubleshooting the LPG Fuel System ............

Checking the IMPCO System...............................................................

Component Checking and Repair.........................................................

Bulkhead Fitting...................................................................................

LP Lock-off Valve..................................................................................

Vaporizer-Regulator..............................................................................

Carburetors............................................................................................

Section 2. Gasoline Fuel System....................................................................

Characteristics of a Gasoline Fuel System..........................................

Components of a Gasoline Fuel System...............................................

Mechanical Fuel Pump.........................................................................

Electric Fuel Pump...............................................................................

Carburetor.............................................................................................

Updraft Carburetor...............................................................................

Downdraft Carburator..........................................................................

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Fuel Systems page 1

Fuel Supply System...............................................................................

Choke System........................................................................................

The Idle System.....................................................................................

Fuel Cut-off Solenoid.............................................................................

Idle Compensator..................................................................................

Main Metering system..........................................................................

Enrichment system...............................................................................

Accelerating Pump System...................................................................

Maintenance and Troubleshooting.......................................................

Section 3.Diesel Fuel System...........................................................................

Characteristics of a Diesel Fuel System...............................................

Advantages of a Diesel Fuel System....................................................

Compression Ratio................................................................................

Thermal Efficiency................................................................................

Operation of a Diesel Fuel System.......................................................

Components of a Diesel Fuel System....................................................

Electric Fuel Transfer Pump.................................................................

Fuel Filter..............................................................................................

Fuel Injection Pump..............................................................................

Distributor-Type Injection Pump..........................................................

Injectors.................................................................................................

Direct Injection......................................................................................

Indirect Injection...................................................................................

Maintenance and Troubleshooting.......................................................

Priming the Fuel System.......................................................................

Electric Fuel Transfer Pump.................................................................

Fuel Filter..............................................................................................

Injectors..................................................................................................

Testing Injectors....................................................................................

Injection Pump......................................................................................

Timing of Injection Pump to the Engine...............................................

Fuel System Suction Leaks...................................................................

General Notes........................................................................................

Section 4. Compressed Natural Gas ...............................................................

What is Natural Gas.............................................................................

CNG Tank..............................................................................................

Fuel Gauge.............................................................................................

Emergency Shut-off Valve....................................................................

Start Up and Shut Down Procedures...................................................

Refueling................................................................................................

Servicing the CNG Fuel System...........................................................

Leak Testing..........................................................................................

System Adjustment...............................................................................

Troubleshooting..................................................................................... © Copyright Clark Material Handling Company 1990.

Revised 1998.

Fuel Systems page 2

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About This Class Welcome to class IC-101: Clark Lift Truck Fuel Systems.

This class consists of four sections:

•

IMPCO LPG Fuel System

•

Gasoline Fuel System

•

Diesel Fuel System

•

CNG Fuel System

Clark Lift Trucks may be fueled by LPG, CNG, gasoline, or diesel fuel. The pw1)ose of this class is to introduce you to each of the fuel systems, identify the components of each system, and examine possible troubleshooting methods.

The LPG section begins with a discussion of the properties of LPG, which is followed by a description of the operation of an LPG system. Both the Gasoline and Diesel sections begin with a description of that system's operation. Also included is a CNG supple­ ment. Discussions of components, maintenance and troubleshooting follow in all four sections.

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Fuel Systems page 3

Safety The following messages may be used to emphasize important information: Note: This message is used when special information, instructions or identification is required relating to procedures, equipment, tools, pressures, capacities and other special data.

Important: This message is used when special precautions should be taken to ensure a correct action or to avoid damage to or malfunction of the truck or a component.

CAUTION: This message is used as a reminder of safety practices which can result in personal injury if proper precautions are not taken.

WARNING: This message is used when a hazard exists which can result in injwJ1 or death if proper precautions are not taken.

DANGER: This message is used when an extreme hazard exists which will result in death or serious injury if proper precautions a1·e not taken.

WARNING: Always be sure to follow all safety precautions. Before you take any action, determine whether it could result in injury to yourself or a by­ stander. Always follow these safety guidelines: Park the truck in a well-ventilated area before working on it.

Avoid smoking or any open flame. There is always a danger of explosion when you are working around any fuel system.

Wear safety glasses.

Wear safety gloves, especially when working on high pressure, frosted lines or components.

Remove all jewelry. It may cause sparks or get caught on something.

Fuel Systems page 4

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Section 1. IMPCO LPG Fuel System The IMPCO LPG Fuel System is a liquid withdrawal system. In this system, fuel flows from the tank to a vaporizer surrounded by coolant from the cooling system. Here the fuel is vaporized and then it flows to the carburetor.

The engines used for the IMPCO LPG Fuel System are identical to those which burn gasoline except for the fuel system.

LPG-run engines have the following characteristics when compared to gasoline-run engines: 1. The same compression ratios 2. The same exhaust valves and seats 3. Colder spark plugs 4. The same distributor 5. Different timing:

9 degrees for LPG, 6 degrees for gasoline, for trucks equipped with the 2.6L engine.

9 degrees for LPG, 4 degrees for gasoline, for trucks equipped with the 2.4L engine.

Characteristics of LPG LPG (Liquid petroleum gases) such as propane and butane, are obtained from natural gas wells, oil wells and from gasoline refineries where they are produced as a by-prod­ uct. LPG has the unique property of being stored and transported in a liquid state and at relatively low pressures. When it is released into the atmosphere or into an expan­ sion chamber it then vaporizes into a dry gas. Both propane and butane have much lower boiling or vaporization points than gasoline: minus 44 degrees for propane and plus 32 degrees for butane, while it is over 100 degrees for gasoline. The temperature at which a liquid boils at atmospheric pressure determines how a liquid must be stored. Thus, butane and propane must be stored under pressure to prevent their vaporization, whereas gasoline, with a much higher boiling point, can be stored with­ out being under pressure.

The effective vapor pressure of LPG is directly related to temperature, with propane ranging from 24 PSI at zero to 225 PSI at 120 degrees. Butane ranges from zero PSI at zero degrees to 56 PSI at 120 degrees. It is this vapor pressure that eliminates the need for fuel pumps in LPG.

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Fuel Systems page 5

Another characteristic of LPG is that it is heavier than air. Therefore suction fans and complete venting are necessary in maintenance pits and confined low areas.

LPG is an odorless gas. An odorant is added to LP Gas to help detect leaks. If at any time this odor is detected, immediately shut off the engine and look for the cause of the leak. Again, make sure that the area is well ventilated.

PRECAUTIONS There is always danger of explosion and fire with any fuel, and LP-Gas is no exception.

LP-Gas is a liquid while under pressure in a tank, but vaporizes almost instantly, at ordinary temperatures, upon its release. Escaping LP-Gas will generally disperse in moving air. But, since it is heavier than air, it seeks the lowest level. Thus, it can drift a considerable distance from the source and lie as an explosive mixture for some time before it completely disperses. It is therefore important to have adequate ventilation when repairing an LP-Gas system, or changing or filling tanks.

If the scent of the added odorant is detected, take immediate steps to eliminate leaks in the LP-Gas system.

Some gas usually escapes when fuel tanks are changed, but even this small amount can be reduced or eliminated with proper techniques. The shut-off valve on the tank should be completely closed during this operation.

A screw or snap-type quick disconnect coupling is attached to the shut-off valve. It requires no tools to operate. When disconnected it automatically seals off any flow through the valve and the hose. For maximum safety, however, always close the shut­ off valve, run the engine until it stops, and turn off the ignition switch before discon­ necting the coupling.

Fuel Used: HD-5 Propane

HD-5 propane is the most efficient LPG fuel for internal combustion engines used in mobile units which have constantly varying engine speeds and loads.

HD-5 propane contains a minimum of 90 percent propane, a maximum of five percent propylene, and a maximum of five percent contaminants such as oil, water and corro­ sive compounds.

This fuel has been developed to improve engine performance and to prevent knock through higher octane ratings.

Fuel Systems page 6

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Function of Basic IMPCO LPG Fuel System The IMPCO LPG fuel system is a "liquid" withdrawal system. This means that liquid fuel flows from the tank to an LP lock-off valve and filter. From there the liquid fuel flows to a vaporizer regulator. The vaporizer regulator is surrounded by coolant from the cooling system. At this point, the fuel is vaporized and then flows to the carburetor.

Components of Basic IMPCO LPG Fuel System The complete LPG system consists of a tank to hold the fuel under pressure in a lique­ fied form, a lock-off valve to block the flow of fuel from the tank when the engine is not running, a vaporizer-regulator to lower the fuel pressure and allow the liquid fuel to become a vapor, and a carburetor to mix the vapor with air and feed the mixture to the engine Shut-Off Valve

Hydrostatic Relief VaJve

Vaporizer­ Regulator

Fuel Line

' Vacuum SWitch /

I

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Lock-OH Valve

Fuel Systems page 7

LPG Tank The fuel tank may be a permanent mount or replaceable storage cylinder for LP fuel.

Working pressure ranges between 25 and 240 PSI depending upon surrounding ambi­ ent temperatures.

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One end of the tank is equipped with a shut-off valve, fuel gauge, safety relief valve and vent.

The vent valve should be opened manually only when filling or cleaning the inside of the tank valve. The tank should always be mounted or stored so that the relief valve is pointing up, or at the top of the cylinder. The LPG tank mounting bracket has a posi­ tioning pin that engages a mating hole in the tank flange at the 6 o'clock position to ensure that the tank is held in the proper position with the relief valve up.

The safety relief valve opens automatically when pressure in the tank rises above 1922 kPa (275 PSI). It closes when the excess pressure is reduced. The fuel gauge is a float level type that indicates percentage of fuel remaining in the tank.

The shut-off valve is operated manually to connect or disconnect the flow of fuel from the tank. The valve opens counter-clockwise and closes clockwise.

Threaded into the base is a maximum withdrawal valve that closes automatically when a large surge of fuel occurs, such as caused by a hose breaking or being discon­ nected. At the end of each shift, close the shutoff valve and run the engine until the fuel lines are clear of fuel. Do not tighten more then hand tight to avoid crushing the valve seat.

Fuel Systems page 8

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