Fundamentals and basic principles of Internal Combustion Engines 2.

Draw/Illustrate the cycle of

Test II: Enumeration; Classification of Internal Combustion engine

According to the basic design

1. Reciprocating Engines

2. Rotary Engines

according to method of igniting the fuel

3. Spark plug ignition (S.I)

4. Compression Ignition (C.I.)

5. Fuel Injector

According to Stroke per cycle

6. 4 stroke cycle – Otto cycle

7. 2 stroke cycle
According to Working cycle

8. otto cycle

9.diesel cycle

10.dual combustion cycle

1. Charge consisting of fresh air mixed with the fuel is drawn

into the cylinder due to the vacuum pressure created by the

movement of the piston from TDC to BDC.

a Suction stroke

b. Compression stroke

c. Expansion stroke

d. Exhaust stroke

2.Burned gases expel out due to the movement of piston from

BDC to TDC.

a. Suction stroke

b. Compression stroke

c. Expansion stroke

d. Exhaust stroke

3. fresh charge is compressed into clearance volume by the

return stroke of the piston and ignited by the spark for

combustion

a. Suction stroke

b. Compression stroke

c. Expansion stroke

d. Exhaust stroke

4. high pressure of the burnt gases force the piston towards

BDC and hence power is obtained at the crankshaft

a. Suction stroke

b. Compression stroke
c. Expansion stroke

d. Exhaust stroke

5. thermodynamic cycle for Si/petrol engine

a. rankine cycle

b) otto Cycle

c. Carnot Cycle

d. Diesel Cycle

6.thermodynamic cycle for low speed C1 engine

a. rankine cycle

b. otto Cycle

c. Carnot Cycle

d. Diesel Cycle

7. Constant pressure heat addition (combustion) and heat

rejection process (exhaust)

a. rankine cycle

b. otto Cycle

c. Carnot Cycle

d Diesel Cycle

8. can in general be represented by-CH2n+2

a. Olefins

b. Naphthenes

c, Paraffin

d. Aromatics

9. Also called as cycloparaffins and represented as CnH2n

a. Olefins

b. Naphthenes

c. Paraffin

d. Aromatics

10. It is Colorless, odorless and mostly constitutes methane

a. gasoline

b. diesel

c. natural gas

d. LPG

11. is available in the market in two forms- one is propane and

the other is butane.

a. gasoline

b. diesel

c. natural gas

d. LPG

12. is the lowest temperature of a sample at which the fuel

vapour starts to ignite when in contact with a flame

a. flash point

b. ignition temperature

c. flame temperature

d. critical point

13. is a device which transforms the chemical energy of a fuel

into thermal energy and uses this energy to produce

mechanical work

a. boiler

b. furnace

c, heat engine

d. steam engine

14. The top end of the cylinder which inlet and exhaust valve,

spark plug or injectors are mounted.

a. cylinder block

b, cylinder head

c. cylinder
d. cylinder crank

15. They are based on a six-membered ring having three

conjugated double bonds

a. Olefins

b. Naphthenes

c. Paraffin

d. Aromatics

16. is the liquid part of the naturally occurring organic material

composed mostly of HCs that is trapped geologically in

underground reservoirs - it is not uniform and varies in density,

chemical composition, boiling range etc.

a. Hydrocarbos

b. Bidodiesel

c, Crude Oil

d. heavy oil

17. This is the initial process used in all refineries

a. cracking

b. isomerization

c. distillation

d. filtration

18. Produced from biomass

a. Ethanol

b. Methanol

c. Ethene

d Methane
19. it uses sunlight and catalysts to split water.

a. UVrays-electrolysis

b. Thermal Water Spliting

c. Sunlight Gasification

d. Photo-electrolysis

20. Dead center when the piston is nearest to the crankshaft.

a. crank end center

b. piston dead center

c. bottom end center

d. bottom dead center

Part Il: Problem Solving

Heat Engine

21-23) An engine operates on the air-standard Otto cycle. The

conditions at the start of compression are 27"C and 100 kPa.

The heat added is 1840 kJ /kg. The compression ratio Is 8. and

pressure at the end of each process in the cycle, the thermal

efficiency, and the mean effective pressure.

a. 2245.23K

b. 1789.6K

c. 4159.0k

d.3253.5K

22. Determine the maximum pressure

a. 6759.5kPa

b.8349kPa

c. 8676.1 kPa

d. 10978.45kPa

23. Determine the effective pressure

a. 1379.9 kPa

b.1245.78kPa

c.1129kPa

d. 2211.6kPa

[24-28) An ideal dual combustion cycle operates on 500g of air.

At the beginning of the compression, the air is at 100kPa, 45C.

if rp=1.5, rc= 1.65 and rk=10,determine

24. The initial volume (V1)

a. 0.365

b. 0.455

c. 0.231

d. 0.444
25. Temperature after the compression

a. 600K

b. 800K

c. 937K

d. 900K

26. Pressure at the end of constant volume heat addition

a. 3768

b. 4656

C. 4767

d. 5878

27. the total heat added at constant volume

a. 142.8kJ

b. 133.92kJ

c. 132.2kJ

d. 145kJ

28. heat added at constant pressure

a. 126

b. 425

c. 387

d. 390

29. what is the final temperature after compression of diesel

cycle if the initial temperature is 32C and the clearance is 8%

a. 562

b. 763.84

c. 864

d. 965

30. In an air standard CI engine, compression starts at 100kPa

and 300K. the compression ratio is 16 to 1. The maximum

cycle temperature is 2031K. Determine the thermal efficiency

b. 62.27

C.) 63.27

d. 64.27

Fuels and Combustion

31. A certain coal has the following ultimate analysis:

C= 69%

N2= 5%

H. = 2.5%

S =7%

Determine the amount of oxygen if the heating values of fuel is

26,961.45 kJ/kg.

a. 1.5

b.2.5

c.3.5

d. 4.5

32. A diesel engine consumed 945 liters of fuel per day at

35°C.

If the fuel was purchased at 15°C and 30°API at P29.00/L

Determine the cost of fuel to operate the engine per day.

a. 5677

b. 4677

C. P48 089

d. P27127

33. A logging firm in Isabella operates a Diesel Electric Plant to

supply its electric energy requirements. During a 2 hour period,

the plant consumed 250 gallons of fuel at 80°F.

Determine the overall thermal efficiency of the plant.

a.26.08
b.28

c.30

d. 34.23

34. A bituminous coal has the following composition:

C = 71.5% H = 5.0%

S = 3%

O = 7.0%

N= 1.3%

Ash = 7.6%

W = 3.4%

Determine the theoretical weight of Nitrogen in lb/lb of coal.

a. 2.970

b. 7.526

c. 2.274

d. 6.233

35. A volumetric analysis of a gas mixture is a follows:

Co2=12%

O2=4%

N2=80%

CO= 4%

What percentage of COz on a mass basis?

a. 17.55

b. 15.55

c.12.73

d. 18.73

36. Methyl alcohol (CH›OH) is burned with 25% excess air.

How much unburned oxygen in kg-mol-oxygen/kg-mol-fuel will

there be in the products If the combustion is complete?

d. 0.65
b.0.45

c. 0.37

a. 0.35

37. An ideal gas mixture consists of 2 kmol of N2 and 6 kmol of

COy. The mass fraction of CO, is:

a. 0.176

b. 0.825

c. 0.250

d .0.750

38. A diesel electrie power plant supplies energy for Meralco.

During a 24-hour period, the plant consumed 240 gallons of

fuel at 28°C and pruduced 3930 KW-hr. Industrial fuel used Is

28°API and was purchased at P30 per liter at 15.6°C. What is

the cost of fuel to produce one KW-hr?

a. 6.87

b. 1.1

C. 41.07

d. 5.00

39. A diesel power plant consumed 1 m' of fuel with 30° API at

27°C in 24 hrs. Calculate the fuel rate in kg/hr.

a. 36.21

b. 26.25

c. 29.34

d. 39.42

40. A diesel power plant uses fuel with heating value of 43,000

kj/kg. What is the density of the fuel at 25°C?

a. 840

b. 873

C. 970
d. 940

41-44) Fuel oil, C 12H26 , is burned in air at atmospheric

pressure.

The Orsat analysis for the products of combustion yields 13.1%

C02, 2.0% 0 2, 0.2% CO, and 84.7% N2 . Determine:

41. Moles of water at the product of combustion

a. 14.41

b. 11.89

c..0

d. 16.73

42. Moles of air at the reactants

a. 75.23

b. 11.22

c.3.76

d. 20.03

43. Moles of fuel at the reactants

a. 1.12

b. 1

c.3.23

d. 1.002

44. Theoretical Air fuel ratio

a. 15.78

b. 16.4

C. 23.4

d. 13.78

45. Determine the minimum volume of day tank in m3 of 28deg

API fuel having a fuel consumption of 200kg/hr.

a. 10.43

b. 6.87
c. 5.41

d. 7.56

46. Calculate the higher heating value of liquid dodecane fuel.

The chemical formula of Dodecane is C12H26.

a. 48, 255 kJ/kg

b. 60,221kJ/kg

c. 55,641 kJ/kg

d. 35,245 kJ/kg

47. There are 20kg of flue gases formed per kg of fuel oil

burned in the combustion of a fuel oil C12H26. What is the

excess air in percent?

a. 21

b. 27.67

c.27

d. 8.21

48. A coal has the following ultimate analysis: C= 60 H2= 6%

Ash= 5% S2= 7%, N2= 5% 02= 9% Moisture=8% Determine

the actual air-fuel ratio using 20% excess air.

a. 11 kg air/ kg coal

b. 12kg air/ kg coal

c.13 kg air/ kg coal

d. 14 kg air/ kg coal

49. A gas consists of 70% propane (C›He) and 30% butane

(CaH10) by volume. Determine

49. The theoretical air-to-fuel ratio in molal basis

a)11.5

b. 7

c. 16

d. 23
50. the total number of moles of carbon dioxide

d. 23

a. 3.3

b. 6.3

6.7

d. 145.2

Otto Cycle

34. For an Otto cycle, heat is added at

a. constant volume

b. constant entropy

c. constant pressure

d. constant temperature

35. What is the thermal efficiency of an ideal Otto cycle if the

heat transferred to air during heat addition process is 600 kJ/kg

and the heat rejected is 250 kJ/kg?

a. 65.02%

b. 76.21%

c. 45.62%

d. 58.33%

36. The compression ratio of an ideal Otto cycle is 6. Under the

cold air standard assumption, compute the thermal efficiency

of the cycle?

a. 48.84%

b. 51.16%

c. 58.29%

d. 60.40%
37. An Otto engine has a clearance volume of 7%. It produces

300 kW of power. What is the amount of heat rejected in KW?

a. 170

b. 160

c. 152

d. 145

Diesel Cycle

38. For an air standard Diesel cycle, compression occurs at

a. constant pressure

b. constant volume

c. constant entropy

d. constant temperature

39. What is the final temperature after compression of a Diesel

cycle if the initial temperature is 32°C and the clearance is 8%?

a. 863.84 K

b. 763.84 K

c. 963.84 K

d. 663.84 K

Dual Combustion Cycle

40. At the beginning of the compression process of an airstandard dual cycle with a compression ratio of
18, the

temperature is 300 K and the pressure is 0.1 MPa. The pressure

ratio for the constant volume part of the heating process is

1.5:1. The volume ratio for the constant pressure part of the

heating process is 1.2. Determine the thermal efficiency of the

cycle.

a. 68.53%

d. 100%
c. 67.32%

d. 67.98%

FUELS AND COMBUSTION

41. Methane is bumed completely with 25% excess air.

Compute the number of moles of nitrogen in the products of

combustion per mole of the fuel.

a. 12

b. 7

c. 94

d. 5

42. A typical Industrial fuel oil, CHs, has 20% excess air by

weight. Assuming complete oxidation of the fuel, calculate the

actual air-fuel ratio by weight.

a. 17.56 kg/kgful

b. 15.76 kg/kg

c. 16.75 kg/kg

d. 17.65 kg/kg

43. Ethane, C2H6, is burnt with just twice the stoichiometric

amount of air. How much kilogram air is used to oxidize 6 kg of

fuel?

a. 193

b. 148

c. 139

d. 184

44. Fuel oil in a day tank for use of an industrial boiler is tested

with hydrometer. The hydrometer reading indicates a S.G. =

0.924 when the temperature of the oil in the tank is 35°C.

Calculate the higher heating value of the fuel.

a. 43,852.13 kJ/kg
b. 53,852.13 kJ/kg

c. 58,352.13 kJ/kg

d. 48,352.13 kJ/kg

45. A Diesel electric plant supplies energy for Meralco. During

a 24-hr period, the plant consumed 200 gallons of fuel at 28°C

and produced 3,930 kW-hr. Industrial fuel used is 28° API and

was purchased at P5.50 per liter at 15.6°C. What should the

cost of fuel be to produce one kW-hr?

a. P1.05

b. P1.10

C. P1.069

d. P1.00

46. A constant volume process.

a. Isothermal

c. Isometric

b. Isobaric

d. Isentropic

47. A constant pressure process.

a. Isothermal

c. Isometric

b. Isobaric

d. Isentropic

48. A constant temperature process.

a. Isothermal

c. Isometric

b. Isobaric

d. Isentropic

49. No work is done in non flow process.

a. Isothermal
b. Isobaric

c. Isometric

d. Isentropic

50. The acceleration of a particular body is directly

proportional to the resultant force acting on it and inversely

proportional to the mass

a. Pascals Law

b. Ohm's Law

c. Charles’s Law

d. Newton's Law

51. An energy that is dependent on elevation.

a. PE

b. KE

c. Q

d. U

52. An energy that is dependent on velocity.

a. PE

b. KE

c. Q

d. U

53. Use to measure atmospheric pressure

a. Manometer

b. Barometer

c. Thermometer

d. Hydrometer

54. Use to measure gauge pressure

a. Manometer

b. Barometer

c. Thermometer
d. Hydrometer

55. Use to measure temperature of a matter

a. Manometer

b. Barometer

c. Thermometer

d. Hydrometer