Internal Combustion Engines5.1. Obj

Internal Combustion Engines
5.1. Objectives
1. Be able to list and describe the events that occur in an internal combustion
engine.
2. Be able to describe how a spark ignition (Otto-cycle) engine differs in operation
from a compression ignition (Diesel-cycle) engine.
3. Be able to diagram and describe the events that occur in sequence during each
stroke of a four-stroke cycle engine.
4. Be able to diagram and describe the events that occur in a two-stroke cycle
engine.
5. Given the bore, stroke, number of cylinders, and clearance volume, be able to
calculate the piston displacement, engine displacement, and compression ratio
in both customary and SI units.
5.2. Introduction
There are six primary sources of power in agriculture: human labor, domestic
animals, wind, flowing water, electricity, and heat engines. The primary sources
of power for modern agriculture are the internal combustion engine and electric
motor. Some day, the primary source of power may change to fuel cells, solar
energy, or atomic energy, but in the immediate future the primary sources of power
for agriculture will continue to be internal combustion heat engines and electric
motors.
Internal combustion engines used for agricultural applications range from
those used for one-horsepower garden tools to the hundreds of horsepower
required for very large tractors. Because engines are very common, knowledge
of how and why they work is essential to a successful agricultural manager.
In this chapter, the basic engine types and functions are discussed, as are
some basic calculations concerning engine size (displacement) and compression
ratio.