1. Engine Maintenance Chapter 4 Inboard Diesel Engines Part 1

2. 2 Objectives 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

3. 3 The Diesel Engine Compression Ignition Compression Ignition Air is heated by compression Air is heated by compression fuel is injected and autoignites fuel is injected and autoignites No spark plug No spark plug

4. 4 Diesel Compression Ratios Diesels use high compression ratios to heat the air Diesels use high compression ratios to heat the air 16:1 to 25:1 16:1 to 25:1 8:1 to 14:1 typical for gasoline 8:1 to 14:1 typical for gasoline Fuel metering and timing are critical Fuel metering and timing are critical

5. 5 Three Needs for Diesel Operation Adequate supply of oxygen Adequate supply of oxygen Diesel fuel must be thoroughly atomized Diesel fuel must be thoroughly atomized Atomized fuel must be mixed with the oxygen supply Atomized fuel must be mixed with the oxygen supply

6. 6 Adequate Supply of Oxygen Superchargers or turbochargers are often used Superchargers or turbochargers are often used

7. 7 Diesel Fuel Must be Thoroughly Atomized High pressure injection is needed High pressure injection is needed

8. 8 Atomized Fuel Must be Mixed with the Oxygen Supply Injector pattern assures even burning Injector pattern assures even burning Dirt and water can damage injector Dirt and water can damage injector

9. 9 Clean Fuel is Imperative Two enemies Two enemies Water Water Bacteria Bacteria Two stage filtration is common Two stage filtration is common

10. 10 Governors Governors maintain constant speed under varying loads Governors maintain constant speed under varying loads Mechanical (historical) Mechanical (historical) Electronic (modern) Electronic (modern)

11. 11 Governors Low speed operation Low speed operation High speed operation High speed operation

12. 12 Glow Plugs Aid in cold weather starting Aid in cold weather starting