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 _____.