Engine MaintenanceEngine Maintenance

Chapter 4Chapter 4

Inboard Diesel Engines Part 1Inboard Diesel Engines Part 1

22

Objectives for the StudentObjectives for the Student

1.Have knowledge of how compression ignition is achieved

2.Have an understanding of the various types of fuel injector systems

3.Have an understanding of superchargers, turbochargers, and intercoolers

4.Have an understanding of how governors work

33

The Diesel EngineThe Diesel Engine

Compression Compression IgnitionIgnition Air is heated Air is heated

by by compressioncompression

fuel is injected fuel is injected and and autoignitesautoignites

No spark plugNo spark plug

44

Diesel Compression RatiosDiesel Compression Ratios

Diesels use high compression Diesels use high compression ratios to heat the airratios to heat the air 16:1 to 25:116:1 to 25:1

8:1 to 14:1 typical for gasoline8:1 to 14:1 typical for gasoline Fuel metering and timing are criticalFuel metering and timing are critical

55

Three Needs for Diesel Three Needs for Diesel OperationOperation

Adequate supply of oxygenAdequate supply of oxygen Diesel fuel must be thoroughly Diesel fuel must be thoroughly

atomizedatomized Atomized fuel must be mixed Atomized fuel must be mixed

with the oxygen supplywith the oxygen supply

66

Adequate Supply of OxygenAdequate Supply of Oxygen

Superchargers or turbochargers are often usedSuperchargers or turbochargers are often used

77

Diesel Fuel Must be Thoroughly Diesel Fuel Must be Thoroughly AtomizedAtomized

High pressure injection is neededHigh pressure injection is needed

88

Atomized Fuel Must be Mixed Atomized Fuel Must be Mixed with the Oxygen Supplywith the Oxygen Supply

Injector Injector pattern pattern assures even assures even burningburning

Dirt and Dirt and water can water can damage damage injectorinjector

99

Clean Fuel is ImperativeClean Fuel is Imperative

Two Two enemiesenemies WaterWater BacteriaBacteria

Two stage Two stage filtration is filtration is commoncommon

1010

GovernorsGovernors

Governors maintain constant speed under varying Governors maintain constant speed under varying loadsloads

Mechanical (historical)Mechanical (historical) Electronic (modern)Electronic (modern)

1111

GovernorsGovernors

Low speed Low speed operationoperation

High speed High speed operationoperation

1212

Glow PlugsGlow Plugs

Aid in cold Aid in cold weather weather startingstarting