Classifications Complete Study Guide
Test.
Air cooling system - CORRECT ANSWER Circulation of air flow over the cooling fins on engine cylinders to
remove heat from the cylinders and prevent overheating.
Air jet combustion chamber - CORRECT ANSWER Combustion chamber design with a small, extra valve
that allows a stream of air to enter the combustion chamber to a swirl and combustion efficiency.
Compression ignition engine - CORRECT ANSWER Type of internal combustion engine that squeezes air
in the combustion chamber until it is hot enough to ignite the fuel. A diesel engine is an example of this
type of engine.
Cylinder arrangement - CORRECT ANSWER The position of cylinders in the engine block in relation to the
crankshaft.
Cylinder numbers - CORRECT ANSWER Numbers that identify the cylinders, pistons, and connecting rods
of the engine. Normally, these numbers are stamped on the connecting rod or cast into the intake
manifold.
Dual overhead cam engine [DOHC] - CORRECT ANSWER An engine equipped with two camshafts in the
top of each cylinder head. One cam operates the intake valves; the other operates exhaust valves.
Flat head engine - CORRECT ANSWER Engine in which both the intake and exhaust valves are located in
the engine block. It is also called an L-head engine. This construction is no longer use in automobile
engines but functions in small gas engines.
Four-valve combustion chamber - CORRECT ANSWER Combustion chamber with two intake valves and
two exhaust valves for each engine cylinder to increase flow in and out.
, Hemispherical combustion chamber - CORRECT ANSWER A dome-shaped combustion chamber with
valves tilted on each side of the chamber and a spark plug located near the center. It provides increased
engine aspiration while suffering less heat loss than other designs. The design is commonly nicknamed a
hemi.
I-head engine - CORRECT ANSWER Engine in which intake and exhaust valves are in the cylinder head it
is also called an overhead valve engine
In-line engine - CORRECT ANSWER An engine with its cylinders arranged in a single straight row. Each
cylinder is placed in a straight line parallel to the crankshaft.
L-head engine - CORRECT ANSWER Engine in which both the intake and exhaust valves are located in the
engine block. It is also called a flat head engine. This construction is no longer use in automobile engines
but functions in small gas engines.
Liquid cooling system - CORRECT ANSWER Circulation of a heat absorbing medium through engine
passages, with the accumulated heat dissipated by further circulation through heat exchanger [radiator].
Miller-cycle engine - CORRECT ANSWER Engine designed with a shorter compression stroke and a longer
power stroke to increase efficiency. Commonly, a supercharger is needed to pressurize the intake
manifold and blocked airflow as the intake valve remains open longer to delay compression.
Opposed engine - CORRECT ANSWER An engine with cylinders lying flat or horizontal on either side of
the crankshaft. It is also called a boxer engine.
Overhead cam engine [OHC] - CORRECT ANSWER Engine with cam shafts located in the top of the
cylinder head. Push rods are eliminated and valves can be angled for improved engine performance.
Overhead valve engine[OHV] - CORRECT ANSWER Engine in which intake and exhaust valves are in the
cylinder head it is also called an I-head engine.
Pancake combustion chamber - CORRECT ANSWER A combustion chamber design in which the intake
and exhaust valves are nearly parallel to the top of the piston.