6 M - 4 E N G IN E FUEL
METERING
CORRECT P R O P O R TIO N S
O F FUEL A N D AIR
A T O M IZ A T IO N
SPRAY O F FINE PARTICLES
GREAT AIR C O N T A C T
DISTRIBUTION
U N IF O R M MIXTURE
DELIVERED T O M A N IF O L D
Fig. 1 -Basic Functions
ATOMIZATION
The engine’s source of fuel for power is gasoline. Before
gasoline can be used as fuel for an engine, it must be
atomized which means breaking the fuel into fine
particles so that it can be mixed with air to form a
combustible mixture. Contrary to popular belief,
gasoline in its liquid state is not combustible; only
gasoline vapor will burn. A common example of this is a
cigarette lighter which works fine indoors but then can’t
be lit after you’ve been outdoors in the cold for awhile.
At warmer temperatures, fuels vaporize quickly and so
can be ignited easily but at lower temperatures,
evaporation is slower and accordingly ignition is
impossible or, at least, difficult because of insufficient
vapor.
While this analogy is quite simple, it is an illustration of
the basic problems of carburetor design; that is, the
provision of combustible fuel mixtures over a broad
range of temperature and operating conditions. The
complexity of design problems continues to mount each
year due to a constant effort to reduce exhaust emissions
and at the same time improve operating conditions.
To be combustible, gasoline must vaporize. Vaporization
is the act of changing from a liquid to a gas and this
change of state occurs only when the liquid absorbs
enough heat to boil. This is what happens in a tea kettle
to change water to water vapor, or steam. Heat is
transferred to the water, raising its temperature until it
finally reaches the boiling point, at which time the water
changes to steam and is carried off to atmosphere in this
gaseous form. At seal level, the water will oil at 212°F
but at high altitudes, less heat is required for water to
boil due to lower atmospheric pressure. This is known as
the temperature-pressure relationship; that is, as the
pressure is reduced, the boiling point is reduced. This
law, combined with a process known as atomization, has
important applications in the transformation of liquid
gasoline to a capor for use in combustion.
In a carburetor (Fig. 2), gasoline is discharged into the
incoming air stream as a spray and the spray is then
atomized, or torn into fine droplets to form a mist. The
resulting air-fuel mixture is drawn into the intake
manifold. At this point, the change of state occurs and
the fuel "mist" vaporizes as the result of several factors.
Since the pressure in the intake manifold is far less than
atmosphere, the boiling point of the gasoline is lowered
considerably. At this reduced pressure, latent heat
absorbed from the many air particles surrounding each
fuel particle causes some vaporization, which is further
aided by heat on the intake manifold floor.
Because complete fuel vaporization is the result of many
factors (ambient temperature, fuel temperature, mani
fold vacuum, and intake manifold temperature), it is
easy to see that anything which reduces any one of these
factors will adversely effect vaporization and thus reduce
fuel economy and increase exhaust emissions. Some
examples would be cold weather, an inoperative exhaust
heat control valve, and high overlap camshafts and/or
heavy throttle demands. While the effects from lower
temperatures are obvious, reduction of manifold vacuum
either by valve timing or heavy throttle operation are
highly detrimental to fuel economy due to the higher
pressures (and boiling points) resulting in the intake
manifold which reduces the amount of fuel vaporization
which will occur by the time the charge enters the
combustion chamber. Fuel not vaporized at the time of
induction is, to a large extent, exhausted unburned from
the combustion chamber and can cause high hydro
carbon exhaust emissions.
We know that gasoline, for combustion, must be
vaporized or as the change of state can be loosely
considered, absorbed by air. However, this requirement
LIGHT DUTY TRUCK SERVICE MANUAL
Содержание Light Duty Truck 1973
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Страница 39: ...HEATER AND AIR CONDITIONING 1A 13 Fig 14 Heater Wiring Diagrams LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 53: ...HEATER AND AIR CONDITIONING 1A 27 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 115: ...LIGHT DUTY TRUCK SERVICE M A N U A L HEATER AND AIR CONDITIONING 1A 89...
Страница 123: ...BODY 1B 3 Fig 6 Typical 06 Van LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 149: ...BODY 1B 29 Fig 84 Body Mounting 06 Fig 85 Body Mounting 14 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 171: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 2 Frame Horizontal Checking Typical FRAME 2 3...
Страница 173: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 4 10 30 Series Truck Frame FRAME 2 5...
Страница 174: ...2 6 FRAME LIGHT DUTY TRUCK SERVICE MANUAL Fig 5 Underbody Reference Points G Van...
Страница 177: ...LIGHT DUTY TRUCK SERVICE MANUAL G 10 20 C 10 P 10 30 Fig 2 Front Suspension C P K Typical FRONT SUSPENSION 3 3...
Страница 185: ...FRONT SUSPENSION 3 11 Fig 16 Toe out on Turns LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 229: ...REAR SUSPENSION AND DRIVELINE 4 5 Fig 13 Rear Spring Installation C K Models LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 310: ...5 44 BRAKES C MODELS G MODELS P MODELS Fig 77 Parking Brake System LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 351: ...ENGINE 6 15 Fig ID Sectional View of Eight Cylinder Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 375: ...EN G IN E 6 39 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 376: ...6 4 0 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 377: ...ENG IN E 6 41 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 378: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 37L K Series Engine Front Mount 6 42 ENG INE...
Страница 379: ...E N G IN E 6 43 FRONT MOUNT REAR MOUNT Fig 38L G Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 400: ...6 6 4 ENG INE LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 401: ...ENG IN E 6 65 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 402: ...6 6 6 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 403: ...E NG IN E 6 67 Fig 36V C Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 423: ...EN G IN E C OOLING 6K 13 Fig 16 Overheating Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 424: ...6 K 1 4 ENG INE COOLING Fig 17 Coolant Loss Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 455: ...ENGINE FUEL 6M 31 Fig K13 Accelerator Controls P30 42 454 Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 456: ...6M 32 ENGINE FUEL Fig K15 Accelerator Controls G Van L 6 LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 506: ...CEC PLUNGER IS EXTENDED Fig lid Vacuum Advance Diagram Six Cylinder Engine 6T 14 EMISSION CONTROL SYSTEMS...
Страница 512: ...Fig 18e Vacuum Advance Diagram V8 Engine...
Страница 515: ...EMISSION CONTROL SYSTEMS 6T 23 Fig If Six Cylinder A I R System LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 516: ...6 T 2 4 E M IS S IO N CONTROL SYSTEMS LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 517: ...E M IS S IO N C O N TR O L SYSTEM S 6T 25 Fig 4f Diverter Valve Vent Valve LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 540: ...6 Y 1 2 ENGINE ELECTRICAL Fig 16b Battery Installation C K Series LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 572: ...6Y 44 ENGINE ELECTRICAL Fig 25i V 8 Spark Plug Wire Installation LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 592: ...7M 2 CLUTCHES MANUAL TRANSMISSIONS VIEW B Fig la Clutch Linkage Assy C K Models LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 593: ...CLUTCHES MANUAL TRANSMISSIONS 7M 3 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 594: ...7M 4 CLUTCHES MANUAL TRANSMISSIONS Fig lc Clutch Linkage Assy P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 598: ...7M 8 CLUTCHES MANUAL TRANSMISSIONS LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 656: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 19M Drive Range Low First Gear Typical 7A 14 AUTOMATIC T R A N S M IS S IO N...
Страница 662: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 22M LI Range Manual First Gear Typical 7A 20 AUTOMATIC TRANSMISSION...
Страница 668: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 25M Reverse Range Typical 7A 26 AUTOMATIC T R A N S M IS S IO N...
Страница 739: ...FUEL TANKS AND EXHAUST 8 9 Fig 15 Filler Neck and Vent Hose Van LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 740: ...8 10 FUEL TANKS AND EXHAUST Fig 16 Fuel Feed and Return Pipes Front C K LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 743: ...FUEL TANKS AND EXHAUST 8 13 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 744: ...8 14 FUEL TANKS AND EXHAUST LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 746: ...8 16 FUEL TANKS AND EXHAUST Fig 2 5 Fuel Feed Pipe Front P 105 4 2 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 760: ...8 30 FUEL TANKS AND EXHAUST Fig 40 Exhaust Pipe P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 761: ...FUEL TANKS AND EXHAUST 8 31 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 763: ...FUEL TANKS AND EXHAUST 8 33 LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 781: ...STEERING 9 15 OIL PRESSURE OIL RETURN PORT VALVE BODY Fig 21 Left Turn Position LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 832: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 106 Power Steering Pump Mounting Typical 9 66 STEERING...
Страница 833: ...PUMP ASSEMBLY STEERING GEAR TYPICAL SMALL V8 TYPICAL LARGE V8 STEERING 9 67...
Страница 860: ...9 94 STEERING LEAKAGE AREAS Fig 133 Power Steering Gear Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 861: ...STEERING 9 95 Fig 134 Power Steering Pump Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
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Страница 886: ...11 10 CHASSIS SHEET METAL LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 891: ...ELECTRICAL BODY AND CHASSIS 12 5 LIGHT DUTY TRUCK SERVICE MANUAL...
Страница 897: ...ELECTRICAL BODY AND CHASSIS 12 11 Fig 14 Instrum ent Cluster Assembly C K Models LIGHT DUTY TRUCK SERVICE MANUAL...
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