Unit 1 Principles of Internal
As a heavy-vehicle mechanic, you are concerned with repairing and
replacing worn or broken parts, making various adjustments to vehicles
and equipment, and ensuring that they are serviced properly and
inspected regularly. To perform these duties intelligently, you must
fully understand the operation and function of the various components of
an internal combustion engine. This makes your job of diagnosing and
correcting troubles much easier. This, in turn, saves time, effort,
money, and lives.
This unit discusses the theory and operation of an internal
combustion engine. You also need to become familiar with the terms being
1-1 Internal Combustion Engine
Learning Objectives: Identify the series of events, as they
occur, in both a gasoline engine and a diesel engine. Describe the
differences between a four-stroke cycle engine and a two-stroke
1-2 Classification of Engines
Learning Objectives: Recognize the differences in the
types, the cylinder arrangements, and the valve arrangements of
internal combustion engines.
1-3 Engine Measurements and Performance
Learning Objectives: Identify terms, engine measurements,
and performance standards of an internal combustion engine.