ASE 114 Engines- Chapter 9

To complete a four-stroke cycle in one cylinder, the crankshaft must rotate _____ degrees.

720

Bottom Dead Center (BDC)

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

Direct Injection (DI)

A diesel fuel injection system in which fuel is injected directly onto the top of the piston

Bore

A dimension of cylinder size representing the diameter of the cylinder

Stroke

A term used to describe cylinder size that represents the amount of movement the piston has inside the bore

Combustion Chamber

An enclosed container in which fuel and air are burned for the production of energy

Diesel Engine

An engine that relies on compression rather than electrical ignition to initiate the spark to ignite the air/fuel mixture

Detonation

As used in an automobile, indicates a hasty burning or explosion of the mixture int he engine cylinders. It becomes audible through a vibration of the combustion chamber walls and is sometimes confused with a ping or spark knock.

What type of ICE engine is commonly found in a hybrid vehicle.

Atkinson

Together these two measurements determine the displacement of the cylinder.

Bore is the diameter of a cylinder, and stroke is the length of piston travel between top dead center (TDC) and bottom dead center (BDC).

tech A says weal valve springs can be detected with a vacuum test. tech b says a restricted exhaust can be detected with a vacuum test. who is correct?

Both a and b

which v-type engine valve train design may use four camshafts

DOHC

DOHC

Double Overhead Camshaft

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

Lobes

The part of the camshaft that raises the lifter

Preignition

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

Rotary

a circular motion

A compression test is conducted to check

a cylinder's ability to seal and therefore its ability to compress the air-fuel mixture inside the cylinder.

Efficiency

a ratio of the amount of energy put into an engine as compared to the amount of energy coming out of the engine; a measure of the quality of how well a particular machine works

Oversquare

a term used to describe an engine that has a larger bore than stroke

A cylinder power balance test reveals whether

all of an engine's cylinders are producing the same amount of power.

A hybrid electric vehicle has two different types of power or propulsion systems:

an internal combustion engine and an electric motor.

in what type of engine is the intake valve held open longer than normal during the compression stroke

atkinson cycle

two technicians are discussing compression testing on a hybrid vehicle equipped with an atkinson cycle engine. tech a says the compression reading of an atkinson cycle engine is normally higher than a conventional engine. tech b says a scan tool may be needed to perform the compression test.

b only

Front engine, longitudinal layout is being discussed. Technician A says this layout is used in rear-wheel drive vehicles. Technician B says this layout is used in some front-wheel drive vehicles. Who is correct?

both

Technician A says engine displacement is commonly measured in cubic millimeters. Technician B says it is commonly measured in cubic inches. Who is correct?

both

diesel engines are being discussed. tech a says diesel engines have a distributor-type injection pump. tech b says diesel engines have a common fuel rail and the injectors are controlled by the computer.

both

two techs are discussing diesel engines. tech a says all diesel engines are fuel injected. tech b says glow plugs help ignite the fuel when the engine is cold.

both

both valves are closed on the ___ strokes

compression and power

the volume of the combustion chamber when the piston is at BDC divided by the volume of the chamber when the piston is at TDC is called ___

compression ratio

what component of the engine determines the stroke

crankshaft

the reciprocating movement of the piston is converted into rotary motion by the

crankshaft and connecting rod.

Vacuum gauge readings can be interpreted to identify many engine conditions, including the ability of the engine's

cylinders to seal, the timing of the opening and closing of the engine's valves, and ignition timing.

Top Dead Center (TDC)

denotes with the piston of a cylinder is at the most upper point of its bore

Undersquare

describes an engine that has a larger stroke than bore

Crank Throw

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

glow plugs

electrical device used on diesel engines to warm the combustion chamber and/or fuel when the outside temperatures are low. These allow for quicker cold starts

An oil pressure test measures the pressure of the This test is very important because

engine's oil as it circulates throughout the engine. abnormal oil pressures can cause a host of problems, including poor performance and premature wear.

the component connected to the crankshaft that serves to store some of the engines power is the

flywheel

The basis of automotive gasoline engine operation is the____. This includes the ____ stroke, _______stroke, _______ stroke, and ______ stroke. The four strokes require______ revolutions

four-stroke cycle. Intake, compression, power, and exhaust. Two full crankshaft

Engine oil pressure testing is being discussed. Technician A says that oil pressure should be tested with the engine cold. Technician B says oil with viscosity that is too high may cause lower than specified pressure. Who is correct?

neither

what is compression ratio

none.....

Automotive engines are classified by several different design features such as

operational cycles, number of cylinders, cylinder arrangement, valve train type, valve arrangement, ignition type, cooling system, and fuel system.

The two basic valve and camshaft placement configurations currently in use on four-stroke engines are the

overhead valve and overhead cam.

A cylinder leakage test is performed to measure the

percentage of compression lost and to help locate the source of leakage.

on a 4-cylinder engine that had a firing order of 1342, if number 1 cylinder is on the exhaust stroke, what stroke is number 3 on

power

Compression ratio is a measure of how much ________ compression stroke.

the air and fuel are compressed during the

In an Atkinson cycle engine the intake valve is held open longer than normal during the compression stroke. As a result,

the amount of mixture in the cylinder and the engine's effective displacement and compression ratio are reduced.

Firing order

the order in which the cylinders of an engine move through the power stroke

Selective Catalytic Reduction (SCR)

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

the stroke of an engine is ___ that of a crankshaft throw.

twice

a four stroke cycle engine requires at least ____ valves at the top of each cylinder

two

Which of the following engine problems may be indicated by good results from a compression test and a cylinder leakage test but poor results from a cylinder power balance test?

worn piston rings

a wet compression test is performed on an engine after a dry compression test revealed low compression on one cylinder. if the compression on the low cylinder rises, it indicates___

worn rings