Chapter 2 (FUELS & COMBUSTION) Flashcards
1
Q
Which is not viscosity rating?
A
Entropy Degrees API
2
Q
Percent excess air is the difference between the air actually supplied and the theoretically required divided by
A
the theoretically air supplied
3
Q
What is the apparatus used in the analysis of combustible gases?
A
Calorimeter
4
Q
The viscosity of most commercially available petroleum lubricating oil changes rapidly above
A
180 °F
5
Q
When 1 mol carbon combines with 1 mol oxygen
A
1 mol carbon dioxide
6
Q
What are the immediate undersirable products from the petroleum based lubricating oil when subjected to high pressure and temperature?
A
Gums, resins and acids
7
Q
What kind of bonding do common gases that exist in free state as diatomic molecules experiences?
A
Covalent bonds
8
Q
An Orsat’s apparatus is used for
A
volumetric analysis of the flue gas
9
Q
A theorem that states that the total property of a mixture of ideal gases is the sum of the properties that the individual gases would have if each occupied the total mixture volume alone as the same temperature.
A
Gibbs Theorem
10
Q
A small enough particles suspended in a fluid exhibit small random movements due to the statistical collision of fluid molecules on the particles. This motion is called
A
Brownian motion
11
Q
When two or more light atoms have sufficient energy ( available only at high temperatures and velocities) to fuse together to form a heavier nucleus the process is called
A
fusion
12
Q
What is the residue left after combustion of a fossil fuel?
A
Ash
13
Q
What is formed during incomplete combustion of carbon in fuels?
A
Carbon monoxide
14
Q
A gas produced by the combustion of fuel oil and cannot be found in the fuel gasses is:
A
hydrogen
15
Q
Which of the following chemical reactions in which heat is absorbed?
A
Endothermic reaction
16
Q
A chemical reaction in which heat is given off.
A
Exothermic reaction
17
Q
The colorless, odorless mixture of nitrogen and oxygen, with traces of other gases water vapor and same impurities
A
Air
18
Q
The transfer of air and air characteristics by horizontal motion is called
A
advection
19
Q
Properties of non-reacting gas mixtures are given by :
A
volumetric weighting for molecular weight and density, and geometric weight for all other properties except entropy
20
Q
The process was of separating two or more liquids by means of the difference in their boiling point
A
Fractional distillation
21
Q
The gaseous products of combustion of a boiler which contains carbon dioxide, carbon monoxide, oxygen, nitrogen and water vapor is called
A
Flue gas
22
Q
The substance whose burning with oxygen yields heat energy such as coal, petroleum and natural gas.
A
Fuel
23
Q
Stoichiometric ratio is :
A
chemically correct air-fuel ratio by weight
24
Q
A type of radiation consisting of singly charged particles that generate to intermediate distances
A
Beta radiation
25
The increase velocity past the throat is due to the rapid decrease in the:
fluid density
26
In an oxidation- reduction chemical reaction, all of the following occur except:
nuclear fusion
27
The residual oil left after the distillation of gasoline and kerosene from crude petroleum; yellow to brown oil used as a diesel fuel and for enriching water gas
Gas oil
28
A fuel gas obtained by the destructive distillation of soft coal is called
Coal gas
29
Removing of impurities from a gas by bubbling it through a liquid purifying agent is called
Gas scrubbing
30
During a fusion process, mass is lost and converted to energy according to:
Einstein’s law
31
A finely divided carbon deposit by the smoke or flame is called
Soot
32
Rare gases such as helium, argon, krypton, xenon and radon that are non- reactive are called
Inert gases
33
Kinematics and dynamic viscosity vary from each other only by a factor equal to the:
fluid density
34
The following properties are different for isomers of the same chemical compound except:
number of atoms in amole of each isomers
35
Atomic weights of the elements in the periodic table are not whole numbers because of
The existence of isotopes
36
The tendency of a pure compound to be composed of the same elements combined in a defined proportion by mass
The law of definite proportions
37
What is the effect of a catalyst in a chemical reaction?
lower the activation energy
38
The relationship between the concentration of products and reactants in a reversible chemical reaction given by
the equilibrium constant
39
What fuel gas obtained by the destructive distillation of soft coal?
Coal gas
40
The process of splitting the nucleus into smaller fragments
fission
41
The ash that us remover from the combustor after the fuel is burn is the
bottom ash
42
A mixture of hydrogen and carbon monoxide made by passing steam over hot coke
water gas
43
All of the following are true of non-stoichiometric reactions except
non- stoichiometric reactions are rare in the combustion process
44
Is the ratio of the volume at the end of heat addition to the volume at the start of heat addition
cut-off ration
45
Piston rings are made of
cast iron
46
Low power is due to
low injection pressure
47
A branch system of pipes to carry waste emissions away from the piston chambers of an internal combustion engine is called
Exhaust manifold
48
The type of filter where the filtering elements is replaceable
metal edge filter
49
When four events takes place in one revolution of a crankshaft of an engine, the engine is called
two stroke engine
50
Which of the following does not belong to the group
Time injection system
51
Specific heat capacity is an SI derived unit described as:
J/kg °K
52
A device whose primary function is to meter the flow of refrigerant to the evaporator
Thermostatic expansion valve
53
The internal combustion engines never works in
Rankine cycle
54
The general chemical formula for all hydrocarbons is CnHm. In different combinations of interest, as internal combustion engine fuel, n varies from:
1 to 26
55
The general chemical formula for all hydrocarbons is CnHm. In different combinations of interest, as internal combustion engine fuel, m varies from:
2 to 54
56
The general formula of a paraffin fuel is
CnH2n+2
57
Napthenes and olefins are types of hydrocarbons with chemical formula of
CnH2n
58
Which of the following types of hydrocarbons have chemical formula of CnH2n-2?
Diolefins
59
Which of the following types of hydrocarbons have chemical formula of CnH2n-4
Asphaltics
60
What is the chemical formula of an Aromatic type of hydrocarbon fuels?
CnH2n-6
61
At atmospheric condition, hydrocarbon molecules with a low number of carbon atoms, 1 to 4 are
Gases
62
Hydrocarbons with 5 to 15 carbon atoms are:
more or less volatile light oils
63
Hydrocarbons with 16 to 26 atoms are referred to as:
heavy oils
64
In a four stroke engine if a valve opens 25 ° before B.D. C. and close 10 ° after T.D.C. the valve should be
exhaust valve
65
In a hot wire anemometer the rate of heat loss from sensing elements is a function of:
velocity of flow
66
Sticking valves
valve springs of defective material
67
Detonation of pinging noise is due to:
late timing of fuel injection
68
The thermal efficiency of a dual cycle engine with fixed compression ratio and fixed quantity of heat and with increase in pressure ratio will:
increase
69
Scavenging efficiency of a four stroke diesel engine is:
between 95% and 100%
70
Volumetric efficiency of a well designed engine may be in the range of:
75 to 90 per cent
71
During idling in a compression ignition engine the air fuel ratio may be of the order:
30
72
Vapor lock is
complete or partial stoppage of fuel supply because of vaporization of fuel in supply system
73
Flash point of liquids is the temperature at which:
The fuel emits vapors at a rate which produces an inflammable mixture with air
74
The mean effective pressure of a diesel cycle having fixed compression ratio will increase if cut off ratio is
increased
75
Hot spots
are the spots where heavier functions of fuel are vaporized
76
Flash point for diesel fuel oil should be:
maximum 49 °C
77
Morse test is conducted on :
multi-cylinder engines
78
Prony brake is used for testing of:
small engines
79
Clog point of an oil refer to:
the temperature at which paraffin and waxes in oil start precipating
80
Otto cycle consists of
two isentropic and two constant volumes processed
81
Diesel cycle consists of:
two isentropic, one constant volume and one constant pressure processes
82
Which is not correct for calculating air standard efficiency?
Gases dissociate at higher temperatures
83
The king pin inclination is generally:
between 2 ° and 5 °
84
For balancing single cylinder engine a counter weight is added to:
Crank
85
To measure a clearance between the valve and tappet of an automobile engine we use a
feeler gauge
86
By supercharging:
thermal efficiency of the engine can be improved
87
Speedometer drive is generally taken from
front wheel
88
Odometer is:
an instrument used for distance measurement
89
Automobile radiator is filled with
soft water
90
The ignition coil acts as:
a step up transformer
91
The self starting motor for automobiles is a:
DC series motor
92
Starting motor current may be about
25 A
93
As a rule before the piston are removed, it is essential to remove the:
piston rings
94
Common causes for excessive oil consumption include:
high speed and worn engine
95
The device that is used for reducing the exhaust noise is called
muffler
96
The device that is used to measure the clearance between the valve and tappet of an internal combustion engine is measured by using:
feeler gauge
97
Which of the following instrument is used measuring specific gravity
Hydrometer
98
Exhaust gas leakage into a cooling system is most likely to occur because of defective:
cylinder head gasket
99
Clutch slippage with clutch is engaged is specially noticeable
during acceleration
100
To engage securely and prevent dragging the clearance between release bearing and release collar in a clutch is generally:
2-3 mm
101
Gudgeon pins are made of:
A. same material as that of piston
B. cast iron
C. hardened and ground steel
D. none of these
none of these
102
Latex is:
a milky juice of rubber
103
Cross wire grooves on tires
absorb shocks because of road unevenness
104
The diesel pump is designed to supply fuel
insufficient quantity in accordance with the engine speed
105
The fuel injected into a cylinder in Diesel engine, when the piston is:
approaching T.D.C. during compression stroke
106
In the cam, the distance between the base circle and the nose is known as
lift
107
Dirt or gum in fuel nozzle or jets can produce:
smoky black exhaust
108
Oil pan is attached:
to the bottom of the cylinder block
109
Excess oil consumption in engine may be because of :
any of the above
110
Wheel base of the vehicle is the:
distance between front and rear axles
111
The percent of heat released from fuel-air mixture, in an internal combustion engine which converted into useful work is roughly
20-25 per cent
112
The efficiency of hydraulic braking system is:
about 90 per cent of
113
The instrument that is used to check the state of charge of a battery is called a
hydrometer
114
When not in use, the self discharge of an automobile battery in dry weather is generally:
0.5 to 1%
115
A laminated glass on cracking:
sandwitched layer taps the fragments
116
Wax is applied on car body as:
any of the above
117
A spark voltage requires a voltage of:
220 V
118
The minimum cranking speed in petrol engine is
60-80 rpm
119
Which oil is more viscous?
SAE 80
120
Engine oil is generally changed after:
2500-6000 km
121
The most probable cause for uneven wear of tires for a truck is
any of the above
122
In a vehicle the most probable cause for hard steering may be:
any of the above
123
Poor compression in a two stroke engine cannot be because of :
leaky valves
124
The number of exhaust manifolds in a V-8 engine is:
two
125
The device for soothing out the power impulses from engine is known as:
fly wheel
126
The firing order in case of four cylinder in- line engines is generally
A. 1-2-4-3
B. 1-3-4-2
C. 1-4-3-2
either B or C
127
In case of four cylinder opposed cylinder engines, the firing order is
1-4-3-2
128
In a four stroke engine , for the combustion of one liter of fuel, the volume of air needed would be approximately
9-10 cu.m
129
Theoretically air needed for the combustion of one kg of fuel is:
14.5 kg
130
Which of the following is the cause of loss power?
Low injection pressure
131
A valve in the carburetor of an internal combustion engines which regulates the proportion of air gasoline vapors entering the cylinder
Choke valve
132
What device combines air and fuel for burning in cylinder?
Carburetor
133
A passive restraint device consisting of bags in front of the driver and passenger
Air bag
134
The heat exchanger used in an Ericsson cycle is:
recuperator
135
In stirling engine, the heat added during
isothermal process
136
In an Otto engine, the heat is added during
isometric process
137
Exhaust stroke of gasoline engine is also known as
scavenging
138
The mechanical efficiency of a device is the ratio of the
ideal energy input to the actual energy input
139
The smallest subdivision of an element that can take place in a chemical reaction is a/an
atom
140
The smallest subdivision of a compound that can exist in a natural state is a/an
molecule
141
Elements with different atomic weights but the same atomic number are:
isotopes
142
All of the following are characteristics of metals except:
tendency to form brittle solids
143
The following are all characteristics of nonmetals except
being reducing agents
144
Graduations in the properties of elements from one elements to the next are less pronounced in:
groups
145
All of the following are components of a chemical elements except:
ions
146
Which of the following is not a prefix used in naming isomers?
Bi
147
All of the following are types of chemical bonds except:
nuclear bonds
148
The equilibrium distance between elements in an ionic bond is function of all the following except:
atomic weight
149
Which of the following statements is not a characteristic of ionic compounds?
They are good electrical conductors in the solid phase
150
What kind of bonding do common gases that exist a free state as diatomic molecules experience?
Covalent bonds
151
Measure are diffuser’s ability to increase the pressure of the fluid is:
pressure recovery factor
152
A decrease in stagnation pressure will decrease the mass flux through the:
diverging nozzle
153
What is the main power generating plant that produces the most electricity per unit thermal energy in the fuel input and has the greatest surplus pf electricity for most cogeneration system?
Diesel engine
154
Air standard efficiency of a diesel engine depends on
compression ratio
155
What is meant by brake horsepower?
Actual horsepower delivered to the engine drive shaft
156
Average pressure on a surface when a changing pressure condition exist
mean effective pressure
157
What air pressure is needed for air starting a diesel engine?
250 psi
158
Mechanical energy of pressure transformed into energy of heat:
Enthalpy
159
Ignition of the air-fuel mixture in the intake of the exhaust manifold
Backfire
160
The total sulfur content in a diesel fuel must not exceed
0.5%
161
The color of lubricating oil:
does not indicate qualities
162
There are two broad types in the classification of lubricating oils, these are straight and
additives
163
Most commercially available petroleum lubricating oil deteriorates starting from operating temperature of:
200 °F
164
An Orsat apparatus is used for:
volumetric analysis of the flue gases
165
The indicator used to determine the anti-knock characteristics of gasoline
Octane number
166
Amount of heat liberated by the complete combustion of a unit weight or volume of duel is
heating value
167
Air the controls the rate of combustion in the combustion chamber is known as:
secondary air
168
Total sulfur content in a diesel fuel oil must not exceed
0.5%
169
Percentage of excess air is the difference between the air actually supplied and the theoretically required divided by:
theoretical air supplied
170
When fuel oil has a high viscosity then the fuel oil
will flow slowly through pipes
171
Engines using heavy fuels require heating of the fuel so that the viscosity at the injector is:
150 SSU or slightly higher
172
A gas produced by the combustion of fuel oil and cannot be found in the flue gases is:
hydrogen
173
Amount of heat liberated by the complete combustion oa a unit weight or volume of fuel is:
heating value
174
The products of complete combustion of hydrocarbons
Carbon dioxide and water
175
When the water in the products of combustion is in the vapor state, the heating value is:
lower heating value
176
At what temperature wherein an oil of any grade becomes cloudy and it freezes, thus its application is limited.
Cold point
177
Dry air can be approximately as__ % oxygen and ____% nitrogen by mole numbers
21% and 79%
178
When H2O in the products of combustion is in liquid form, the heating value is known as
higher heating value
179
Flow of fluids wherein its particles do not have definite paths and the paths of the individual and distinct particles cross one another is:
turbulent flow
180
If the composition of hydrocarbon fuel is known, the ratio between the nitrogen and oxygen that is supplied in air is:
constant
181
The property of liquid in which they extend resistance to angular or shear deformation is:
Viscosity
182
A property of lubricating oil that measures the thickness of the oil and will help determine how long oil will floe at a given temperature is known as:
viscosity
183
the temperature at which lubricating will form a cloud
Cloud point
184
The ideal cycle based on the concept that the combustion process is both diesel and gasoline in the combination of heat transfer processes that is constant pressure and constant volume.
Dual cycle
185
The unit used for expressing API gravity is:
degrees
186
API gravity of water is :
10
187
Which of the following variety of coal has highest ash content?
Lignite
188
Which of the following is petroleum fuel?
Naphta
189
Diesel engjne fuels are rated by:
cetane number
190
Which of the following needs to be filtered in a diesel engine?
Air, diesel oil and lubricating oil
191
ASTM coal classification is bases on:
proximate analysis
192
The minimum amount of air required for a complete combustion of fuel is called
theoretical air
