Chapter 5

throttle changes

A major advantage of a supercharger is a very quick response to ___________.

cetane number

A percentage indicating the ignition quality of diesel fuels

octane number

A percentage indicating the ignition quality of gasoline fuels or petrol

turbo lag

A phenomenon in which a turbocharger takes some time of cycles of revolution before it improves the engine efficiency.

pressure drop

Air moving through any flow passage or past any flow restriction undergoes a _______.

less than 100%

All compressors have isentropic efficiencies ______,so the actual power needed will be greater than the ideal.

hotter

All intake systems are ____ than the surrounding air temperature and will consequently the incoming air

open simultaneously

At TDC at the end of the exhaust stroke and the beginning of the intake stroke, both intake and exhaust valve are ________ for a brief moment

open

At TDC at the end of the exhaust stroke and the beginning of the intake stroke, both intake and exhaust valves are ______ simultaneously for a brief moment

do not readily self-ignite

Characteristics of fuels having high octane number.

fuel evaporation

Direct injection engines will experience no volumetric efficiency loss due to ________.

exhaust gas recirculation

EGR stands for

intake valve closes later

If ________ than the ideal point, air beong compressed by the piston will force some air back out of the cylinder

higher

If the temperature at the start of the compression stroke is higher, all the temperatures in the rest of the cycle will also be _______.

naturally aspirated engines

In a ________ volumetric efficiency would always be less than 100%

less than 100%

In a naturally aspirated engine, volumetric efficiency will always be ________

injectors

In modern automobile engines, the fuel is added with _______, as with supercharged engines

lowers its density

Intake systems consequently heat the incoming air, which _______.

aftercooler

It is a device that reduces the temperature of compressed air after it has passed through the turbocharger or a supercharger

turbocharged

It is the effect of an internal combustion engine equipped with a turbocharger

volumetric efficiency

It is the parameter increased when stratified charged engines are operated at no throttle

70% to 90%

It is the range of overall efficiency for engines equipped with turbochargers

100,000 to 130,000 RPM

It is the range of speed usually used in the exhaust turbine system

sudden change in throttle

It is the situation in which turbo lag occurs

no throttle

It is the throttle characteristics at which stratefied charged engines are usually operated

throttle

It refers to the means of controlling an engine's power by regulating the amount of fuel or air entering the engine.

air flow rate

On SI engines, _________ through the intake manifolds is controlled by a throttle plate usually located at the upstream end

throttle plate

On SI engines, air flow rate through the intake manifold is controlled by a _____ usually located at the upstream end

intake stroke

Part of the Otto engine cycle where the air is taken into the combustion chamber at constant pressure

two or more

Some superchargers are made up of _____ compressor stages with an aftercooler following each stage.

crankshaft

That part of the engine which transmits the reciprocating motion of the pistons to the driven unit in the form of rotary motion.

inside diameter

The _____ of the runners must be large enough so that a high flow resistance and the resulting low volumetric efficiency do not occur

later that the fuel vaporizes

The ____________ in the intake system, the better is the volumetric efficiency

fuel injector

The device which sprays the fuel into the cylinder.

runners

The inside diameter of the ________ must be large enough so that a high flow resistance and the resulting low volumetric efficiency do not occur

volumetric efficiency

The later that the fuel vaporizes in the intake system, the better is the _______

parasitic load

The power of the Supercharger is considered a __________ since the power to drive the compressor is from the engine output

valve discharge coefficient

The ratio of the actual flow area to the flow passage area is called the ______.

normal intake valves , intake slots in the cylinder walls

There are two general methods of putting air into the cylinders; through the ________ or through ______

scavenging process

To avoid an excess of exhaust residual, no pockets of stagnant flow or dead zones can be allowed in the _________.

sharp bends

To minimize flow resistance, runners should have no ___________.

intake runners

_______ are the pathways of the air or mixture from the intake manifold into the cylinders

turbochargers

_______ do not use the engine output as a source of power, instead the waste energy from the exhaust is used.

throttle valve

_______controls A/F flow rate into the intake manifold

rich

a qualitative description of the desired air fuel mixture around the spark plug

lean

a qualitative description of the desired air fuel mixture inside the combustion chamber

scavenging

air under pressure enters the cylinder and pushes most of the remaining exhaust residued out the still-open exhaust port. This is called _______

naturally aspirated engines

are engines that rely on atmospheric pressure acting upon a partial vacuum made by the movement of the pistons as it travels down towards the bottom dead center during the suction stroke

combustion gases

are gas mixture after the combustion stage

superchargers

are generally positive displacement compressors running at speeds about the same as engine speed

superchargers

are mechanically driven directly off the engine crankshaft

supercharged

effect of using supercharger

direct injection

engines inject fuel directly into the cylinders.

idle valve

gives a better fuel flow control at idle

valve seat

in an internal combustion engine is the surface against which an intake or exhaust valve rests during the portion of the engine operating cycle when that valve is closed

air filter

is a device for filtering the air, before it goes into the engine, to prevent particles of dust from entering the engine.

torque

is a force acting at a moment distance

valve overlap

is a moment where both the intake valve and exhaust valve are open simultaneously for a brief moment

volumetric efficiency

is a ratio or percentage of what quantity of air-fuel mixture that actually enters the cylinders during suction process to the actual capacity of the cylinder under static conditions

intake manifold

is a system designed to deliver air to the engine pipes to each cylinder, called runners

intake valve

is a valve that allows air/ fuel mixture into the combustion chamber

poppet valve

is a valve typically used to control the timing and quantity of gas or vapor flow into the engine

overhead valve engine

is also called pushrod engine

double overhead cam

is also called twin cam or double cam

power

is defined as the rate of doing work

valve lift

is the distance in which a valve opens

valve lift

is the distance which the valve opens and is usually about 5mm to 10mm.

fuel injection

is the introduction of fuel in an internal combustion engine by means of an injector

work

is the output of any heat engine

intake valve

is the passage way to the cylinder of the internal combustion engine

valve timing

is the precise timing of the opening and closing of the valves

fuel reservoir

is where the fuel is stored

air filter

it filters the air that is entering the intake system

intake

it is desirable to have maximum volumetric efficiency in the _____ of any engine

waste energy

it is the energy used to power the turbocharger

turbine

it powers the compressor of a turbocharger and is mounted on the exhaust flow of the engine

air flow meter

measures the amount of air that is going into the system

blowdown

refers to the phenomenon of combustion gases escaping through the valve during power stroke or before reaching the bottom-dead center.

throttle

the ____ controlls the air flow rate

stroke

the distance a piston travels up or down inside the cylinder

large

the inside diameter of the runners must be ______ enough so that a high flow resistance and the resulting low volumetric efficiency do not occur

runners

the intake manifold on a fuel-injected engine contains passages called ______ to route the fuel mixture to each cylinder

minimal

there is _____ amount of pressure drop across the exhaust turbine because the maximum pressure is only a little above the atmospheric temperature

flow resistance

to minimize _______, runners should have no sharp bends

compression ignition engines

typically have AF input in the range of 18 to 70.

mechanically driven

unlike superchargers, turbochargers are not _______

air

when most of the exhaust gas is out, the exhaust port closes and the cylinder is filled with _____.