Engine repair vocabulary

Lobes

the part that of the camshaft raises the lifter

combustion camber

the space between the top of the piston and the cylinder head where the engine combustion takes places

double overhead camshaft

dual overhead camshaft

stroke

describe cylinder size that represent the amount of movement the piston has inside the bore

top dead center

common term to denote with piston of a cylinder is at the most upper point of its bore

undersquare

describe an engine that has a larger stroke than bore

oversquare

engine with a larger bore than stroke

firing order

the order in which the engine moves through the power stroke

bottom dead center

common term to denote with the piston of a cylinder is the farthest it can be in its bore

Bore

a dimension of cylinder size representing the diameter of the cylinder

crank throw

The distance from the crankshaft main bearing centerline to the connecting rod journal centerline. the stroke of any engine is the crank throw

efficiency

a ratio of the amount of energy put into an engine coming out of the engine measuring the quality of how well a particular machine works

direct injection

diesel fuel injection system in which fuel is injected

diesel engine

an engine that relies on compression rather that electrical ignite to ignite the spark to ignite the air/fuel mixture

Atkinson cycle

the cycle during which the intake valves are kept open for a while during the compression stroke, reducing the actual displacement and the power output of the engine

Glow plugs

an electrical device used on diesel engine to warm the combustion camber and/or fuel when the outside temp is low

Selective catalytic reduction

to clean diesel exhaust, an ammonia like substance is injected into the exhaust stream.

rotary

a circular motion

detonation

indicated a hasty burning or explosion of the mixture in the engine cylinders. can be audible through a vibration of the combustion chamber wall and is sometimes confused with a ping or spark knock

preignition

the process of a glowing spark or deposit igniting the air-fuel mixture before the spark plugs