39 + Interview Questions in Cooling System in Automotive Engine Design Page 1 InterviewSolution

1.	The anti-freeze should have ______specific heat capacity to be compared to the specific heat capacity of the coolant.(a) zero(b) average(c) low(d) highThe question was posed to me during an online interview.The query is from Coolants in division Cooling System of Automotive Engine Design
Answer» The correct option is (d) high Explanation: The anti freezer plays a CRITICAL role in sustaining ENGINE HEAT balance by removing heat. The main requirement of an anti-freeze is that it should have a high specific heat capacity when compared to that of the COOLANT.

Discussion

2.	The boiling point of the coolant should be ______(a) low(b) high(c) medium(d) none of the aboveThis question was addressed to me during an interview for a job.This intriguing question originated from Coolants topic in section Cooling System of Automotive Engine Design
Answer» Right OPTION is (b) high To explain: The BOILING point of them should be high thereby MINIMUM loss due to evaporation and the COOLANT can be operated at the higher temperature.

Discussion

3.	The abbreviation of SCA is ______(a) supplemental Coolant Additive(b) super Cooling Additive(c) standard Coolant Additive(d) strategic Chemical AdditiveI got this question at a job interview.My question is based upon Coolants topic in portion Cooling System of Automotive Engine Design
Answer» Correct option is (a) SUPPLEMENTAL Coolant Additive To explain I WOULD say: SCA is vital for the health and longevity of any diesel engine and its ABBREVIATION is supplemental Coolant Additive. The advantages of SCA is it extends the life and health of the engine, ESPECIALLY older equipment, and also aid in preventing cavitation and pitting in diesel engines.

Discussion

4.	The coolant used in heavy-duty engines should be______(a) green in color(b) fully formulated(c) concentrated(d) blueI have been asked this question in class test.My doubt is from Coolants topic in chapter Cooling System of Automotive Engine Design
Answer» The CORRECT option is (b) fully formulated For explanation I would say: The Coolant for a heavy-duty ENGINE will be fully formulated adopts a PROPYLENE glycol and ethylene glycol as the basic liquid.

Discussion

5.	In a 50% concentration of ethylene glycol (by volume) lowers the freezing point of water to ______Degree Centigrade.(a) -30(b) -50(c) -35(d) -37I had been asked this question at a job interview.Enquiry is from Coolants in chapter Cooling System of Automotive Engine Design
Answer» Right option is (d) -37 The best I can explain: ETHYLENE glycol interferes with the hydrogen bonding NETWORK in pure water. Water FREEZES at 0°C and pure ethylene glycol at -12°C,due to which 50% concentration of ethylene glycol lowers the freezing point of water to -37 degrees CENTIGRADE.

Discussion

6.	The boiling point of ethylene glycol used in the coolant is ______Degree Centigrade(a) 290(b) 195(c) 200(d) 300I had been asked this question in an interview for internship.This intriguing question originated from Coolants in section Cooling System of Automotive Engine Design
Answer» Right ANSWER is (B) 195 Easy EXPLANATION: The boiling point is the temperature at which the vapor pressure of a chemical equals atmospheric pressure. The boiling point of ethylene glycol is 195-degree Centigrade and used as coolant in automobiles. The higher boiling point indicates greater intermolecular force THEREFORE less vapor pressure.

Discussion

7.	The coolant is made up of three components they are ______(a) water, anti-freezer and SCA’s(b) water, fuel, and silicates(c) water, buffers and SCA’s(d) water, SCA’s and defoamersI had been asked this question in an online interview.My question is based upon Coolants in section Cooling System of Automotive Engine Design
Answer» Right answer is (a) water, anti-freezer and SCA’s Explanation: The coolant consists of water and anti-freeze in proper proportion with a small amount of SCA’s. The antifreeze does not let the coolant to freeze in cold CLIMATES and the SCA’s HELPS in the life and health of the engine, especially older equipment.

Discussion

8.	The pH range of Coolant is ______(a) equal to or Greater than 7(b) 0(c) 0-5(d) 3-6I have been asked this question in class test.Query is from Coolants topic in section Cooling System of Automotive Engine Design
Answer» Right answer is (a) equal to or Greater than 7 To elaborate: PH is a scale used to FIND how acidic or basic a given solution is. Acidic solutions have a lower pH, while basic solutions have a higher pH. Coolant OPERATES in neutral or basic CONDITIONS as they should not react with the metals they travel through. So equal to or greater than 7 is preferred.

Discussion

9.	______ Meter is used to measure the Glycol and water ratio present in the coolant?(a) hydrometer(b) refractometer(c) galvanometer(d) voltmeterThe question was posed to me during an online interview.This is a very interesting question from Coolants in section Cooling System of Automotive Engine Design
Answer» The correct answer is (b) refractometer To EXPLAIN I would say: Refractometer is used to measure the glycol water ratio because it offers the best method to IDENTIFY the precise glycol content of the coolant.

Discussion

10.	Carboxylates are added in the Coolant to prevent from ______(a) freezing(b) condensation(c) evaporation(d) corrosionThe question was posed to me by my college director while I was bunking the class.This intriguing question originated from Coolants in portion Cooling System of Automotive Engine Design
Answer» Right option is (d) CORROSION For explanation I would say: Carboxylate INHIBITORS provide corrosion protection by chemically INTERACTING with the metal surfaces where needed, not by universally laying down LAYERS.

Discussion

11.	The qualities of the Anti-freezer must have these Qualities ______(a) average Viscosity(b) no corrosive property(c) must be Miscible(d) all of the aboveThis question was posed to me during an interview.I'm obligated to ask this question of Coolants in section Cooling System of Automotive Engine Design
Answer» The CORRECT answer is (d) all of the above The best explanation: The coolant MUST be MISCIBLE with water and should not be Corrosive when the coolant flows through the JACKETS and should have AVERAGE viscosity.

Discussion

12.	The Fans consumes around ______% of the engine BP If not operated efficiently and economically.(a) 11(b) 5(c) 6(d) 10This question was posed to me in semester exam.I need to ask this question from Components of Water Cooling System in chapter Cooling System of Automotive Engine Design
Answer» Right OPTION is (B) 5 Easiest explanation: The fan is the only part that is always running when the ENGINE runs. The FAB consumes as much as 5% of the engine BP and producing more noise. In modern cars, the fan blades are made with variable pitch TYPE, which may speed-sensitive or temperature-sensitive type.

Discussion

13.	The ratio of Ethylene glycol and Water in the coolant is ______(a) 50:50(b) 10:90(c) 30:70(d) 20:80I have been asked this question during a job interview.I would like to ask this question from Coolants in chapter Cooling System of Automotive Engine Design
Answer» Right option is (a) 50:50 The EXPLANATION: Ethylene glycol keeps hoses and SEALS smooth and raises the coolant’s boiling point. The ratio of Ethylene glycol in water is 50:50 as it must be in balance for the EVAPORATION of water when the ENGINE temperature increases.

Discussion

14.	The additives which are added to lower the Freezing point of the coolant is ______(a) anti- Knocking Agent(b) temperature controller(c) anti freezer(d) isomersThis question was addressed to me in an online interview.This interesting question is from Coolants in portion Cooling System of Automotive Engine Design
Answer» The CORRECT option is (c) ANTI freezer Explanation: The Anti-Freezer additive lowers the FREEZING point of water which HELPS when the temperatures fall very low. Even for hot climates, the use of antifreeze has the incidental advantage that the BOILING point of the cooling water is raised.

Discussion

15.	The material used in the manufacturing of Fans in the cooling system is ______(a) cast iron(b) brass(c) plastic(d) bronzeThis question was addressed to me in a national level competition.My enquiry is from Components of Water Cooling System in chapter Cooling System of Automotive Engine Design
Answer» The correct choice is (c) plastic The best explanation: Plastic due to its lightweight advantage and it has no corrosive nature, the manufacturing cost of the plastic fan is LESS when compared to other MATERIAL, it is also less in WEIGHT due to all these reasons plastic is preferred.

Discussion

16.	For the reduction of noise, the blades are spaced ______ sometimes.(a) evenly(b) unevenly(c) clockwise(d) anti-ClockwiseThe question was posed to me during an internship interview.My doubt stems from Components of Water Cooling System in section Cooling System of Automotive Engine Design
Answer» The correct option is (B) UNEVENLY Explanation: Fan blades maybe four to SEVEN blades that are spaced unevenly so that there is a reduction in the noise which is created. It is generally made of sheet metal, but these DAYS molded plastic material or polypropylene are also being used for making FANS.

Discussion

17.	In Siemens VDO’s Smart coolant pump the pump is operated by the means of ______(a) 12v DC Motor(b) camshaft(c) crankshaft(d) mechanicallyI had been asked this question during a job interview.My doubt stems from Components of Water Cooling System in section Cooling System of Automotive Engine Design
Answer» Right choice is (a) 12v DC Motor For explanation I would SAY: The PUMP works on a 12v DC motor which can be CONTROLLED by the engine MANAGEMENT system so that precise temperature can be maintained.

Discussion

18.	The core material used in the preparation of the radiator core is ______(a) brass(b) steel(c) plastic(d) cast ironI got this question in class test.My question is taken from Components of Water Cooling System topic in section Cooling System of Automotive Engine Design
Answer» CORRECT answer is (a) brass Explanation: The material USED for radiator should be resistant to corrosion, POSSESS higher thermal conductivity and form easily, apart from having adequate strength. Brass is the material used in the core preparation of the radiator core. Aluminum is ALSO used for weight and cost considerations.

Discussion

19.	In Bellows type thermostat the valve movement depends upon the difference between _____(a) temperature(b) vapor pressure(c) velocity(d) dischargeI have been asked this question during an interview.Enquiry is from Components of Water Cooling System topic in section Cooling System of Automotive Engine Design
Answer» The CORRECT ANSWER is (b) vapor pressure The explanation is: The VALVE movement depends upon the difference between the VAPOUR pressure at any given temperature and the cooling pressure.

Discussion

20.	The pump mounted at the front end of the engine is driven from the ______by means of V-belt.(a) camshaft(b) crankshaft(c) motor(d) electric PulleyThe question was posed to me in an interview.My question is from Components of Water Cooling System topic in division Cooling System of Automotive Engine Design
Answer» CORRECT ANSWER is (B) crankshaft Explanation: The coolant pump is a necessity for the forced circulation type of engine cooling system. The pump is MOUNTED at the front end is driven from the crankshaft using V-belt. Centrifugal type pump is the one that is used for this purpose.

Discussion

21.	______ is used to keep the cooling water automatically to a predetermined value.(a) motor(b) overhead valve(c) overflow pipe(d) thermostatThis question was addressed to me in semester exam.I'm obligated to ask this question of Components of Water Cooling System topic in chapter Cooling System of Automotive Engine Design
Answer» CORRECT OPTION is (d) thermostat Explanation: A thermostat is used to automatically KEEP the cooling water temperature at a predetermined value. It ALSO helps the engine to reach the operating temperature as soon as POSSIBLE after starting the engine.

Discussion

22.	______ valves Operates to avoid the collapse of the radiator.(a) pressure(b) inlet(c) outlet(d) vacuumI got this question in unit test.Origin of the question is Components of Water Cooling System in division Cooling System of Automotive Engine Design
Answer» RIGHT option is (d) vacuum Easy explanation: When the vacuum is CREATED inside the vacuum valves OPERATES and stops the collapse it usually operates when the vacuum exceeds about 5Kpa.

Discussion

23.	______ Reservoir is provided to provide excess coolant as the engine temperature increases.(a) filler Neck(b) blow off(c) expansion(d) compressionThe question was asked in my homework.This interesting question is from Components of Water Cooling System in portion Cooling System of Automotive Engine Design
Answer» The correct choice is (C) expansion The explanation: Expansion reservoir is connected to the radiator in such a way that it receives the excess coolant as the engine TEMPERATURE increases. When the cooling WATER cools down, its volume DECREASES, and the coolant in the reservoir returns to the radiator keeping the system full of coolant.

Discussion

24.	To maintain the coolant at a higher pressure than the atmosphere ______ are provided in the Radiator.(a) fins(b) radiator cap(c) blow-off valve(d) overflow pipeThe question was asked in an interview for internship.This interesting question is from Components of Water Cooling System in division Cooling System of Automotive Engine Design
Answer» The correct ANSWER is (b) RADIATOR cap For EXPLANATION: The pressure cap forms an airtight joint due to which the coolant is MAINTAINED at some higher pressure than the atmosphere due to which the boiling point of the coolant is RAISED.

Discussion

25.	For Heavy Duty Application Radiator ______ is automatically controlled through the compressed air taken from the brake system.(a) spring(b) shutter(c) gasket(d) tankI had been asked this question in an online interview.I want to ask this question from Components of Water Cooling System in portion Cooling System of Automotive Engine Design
Answer» The correct choice is (B) shutter Easy explanation: The shutter REMAINS closed during the starting and it gradually opens up as the ENGINE attains its working temperature, thus ALLOWING the fresh air to COME into contact with the radiator.

Discussion

26.	In a Tubular Type Radiator Core the tubes are made in the range of ______to_____(mm) sheet.(a) 0.1 to 0.3(b) 0.5 to 0.7(c) 0.2 to 0.4(d) 0.3 to 0.5The question was asked in an international level competition.The question is from Components of Water Cooling System topic in portion Cooling System of Automotive Engine Design
Answer» The correct option is (a) 0.1 to 0.3 For EXPLANATION: The CORE tubes are made from the thinnest possible MATERIAL. Tubes are made from 0.1mm to 0.3 MM sheet; the fins are made about 0.1 mm thick material.

Discussion

27.	According to the maintenance which of the following is true?(a) Air cooling is easier(b) Water cooling is easier(c) Both water and air are easier(d) Oil coolingThe question was posed to me in an international level competition.My enquiry is from Methods of Cooling in chapter Cooling System of Automotive Engine Design
Answer» Right option is (a) Air cooling is easier To explain I would SAY: Air cooling is easier and there are no PROBLEMS LIKE leakage of coolant or fluid as it is absent in the air colling SYSTEM and the ABSENCE of hose pipe results in fewer components to maintain during vehicle service.

Discussion

28.	For the proper maintenance _____number of years is recommended for the Flush of the Cooling System?(a) 5(b) 3(c) 2(d) 1I got this question in an interview.I'm obligated to ask this question of Methods of Cooling in portion Cooling System of Automotive Engine Design
Answer» RIGHT answer is (C) 2 Easiest EXPLANATION: The cooling system Flush keeps the engine running SMOOTH and cool even on the hottest days. The cooling system flush is recommended every two years or every 24,000 to 36,000 miles to remove any RUST or contaminants.

Discussion

29.	Which of the following is absent in the air-Cooled Engine?(a) Radiator(b) Fins(c) Inlet and Exhaust port(d) Cylinder HeadI had been asked this question in exam.My query is from Methods of Cooling topic in section Cooling System of Automotive Engine Design
Answer» The correct choice is (a) Radiator The BEST I can EXPLAIN: The radiator is ABSENT in these types because of which the air-cooled METHOD is light in weight and applicable for two-wheelers as well.

Discussion

30.	The position of the cooling Fan is_____ of the Radiator?(a) behind(b) top(c) bottom(d) in frontI got this question in an interview for job.Question is taken from Methods of Cooling in portion Cooling System of Automotive Engine Design
Answer» The CORRECT option is (a) BEHIND To explain: The position of the fan is behind the RADIATOR and in FRONT of the ENGINE wherein the fan sends the cold air and then cools the fluid present in the Radiator.

Discussion

31.	_____ Type of Wear takes places in the water Jackets of water-cooled engines?(a) mechanical(b) adhesion(c) abrasion(d) corrosionI have been asked this question in an international level competition.The doubt is from Methods of Cooling topic in section Cooling System of Automotive Engine Design
Answer» The correct CHOICE is (d) corrosion Easy EXPLANATION: Corrosion Wear TAKES place as the water changes its state from liquid to gas the water droplets TEND to remain in the JACKETS and in the presence of oxygen the corrosion attack takes place.

Discussion

32.	The 12v DC Fan present in the Pump Circulation System is operated by_____ Sensor.(a) mass airflow(b) throttle Position Sensor(c) engine Coolant Sensor(d) steering Angle SensorThis question was addressed to me by my college professor while I was bunking the class.The above asked question is from Methods of Cooling in section Cooling System of Automotive Engine Design
Answer» Correct CHOICE is (c) ENGINE Coolant Sensor Easiest explanation: The Coolant Temperature Sensor (TPS) can be found ALONG with the Thermostat which sends the real-time READINGS to the ECU and based on the PROGRAM the Fan is operated.

Discussion

33.	In a Thermosyphon System, the rate at which the water circulates is _____(a) proportional to Load and Not to Engine speed(b) not Proportional to Load and Proportional to Engine Speed(c) proportional to Load and Proportional to Engine Speed(d) not Proportional to load and Not Proportional to Engine SpeedI got this question by my school teacher while I was bunking the class.The doubt is from Methods of Cooling in section Cooling System of Automotive Engine Design
Answer» RIGHT CHOICE is (a) PROPORTIONAL to LOAD and Not to Engine SPEED Easy explanation: As the amount of heat generated and cooling rate is maintained by natural convection due to which it is proportional to load and not on the engine speed.

Discussion

34.	For Better Thermal Conductivity ______and ______Alloys are used during the Manufacturing of Fins present in air-cooled Engines?(a) copper and Steel(b) brass and Copper(c) aluminum and Steel(d) bronze and CopperThe question was asked during an internship interview.This is a very interesting question from Methods of Cooling topic in division Cooling System of Automotive Engine Design
Answer» Correct option is (a) copper and Steel The best explanation: The THERMAL CONDUCTIVITY for Copper and Steel is 388.0W/m-C and the density is 8.933×10power3 kilogram per meter cube which is the HIGHEST when compared to other metals and their ALLOYS.

Discussion

35.	The main difference between the Pump circulation System and Thermosyphon System is the presence of ______(a) fan(b) radiator(c) hosepipe(d) pumpThe question was posed to me during an online interview.The doubt is from Methods of Cooling topic in chapter Cooling System of Automotive Engine Design
Answer» The correct answer is (d) pump Explanation: The Pump is USED ALONG with the Thermostat where the Pump is used for the CIRCULATION of COOLANT and the thermostat controls the flow of coolant.

Discussion

36.	What is the correct sequence of the coolant flow in a Thermosyphon system?(a) Engine-Header tank –Radiator-Collector tank(b) Collector tank- Header tank-Radiator- Engine(c) Engine-collector tank- Header tank-Radiator(d) Radiator- Header tank- collector tank- EngineI had been asked this question in exam.I'm obligated to ask this question of Methods of Cooling topic in chapter Cooling System of Automotive Engine Design
Answer» Correct CHOICE is (a) Engine-Header tank –Radiator-Collector tank For explanation: The COOLANT ABSORBS the HEAT from the engine and with the hose pipe flows to the header tank and then loses all of the heat in the radiator and then moves to the collector tank where the coolant is collected.

Discussion

37.	In Cooling system when the cooling is reached beyond the limits leads to______ of viscosity and ______ of the Mechanical Efficiency.(a) increase and Decrease(b) decrease and Increase(c) increase and Increase(d) decrease and DecreaseThe question was asked in exam.Query is from Methods of Cooling in section Cooling System of Automotive Engine Design
Answer» The correct answer is (a) increase and Decrease The explanation: As TEMPERATURE and viscosity are INVERSELY PROPORTIONAL to each other the viscosity of the LUBRICANT Increase and due to this more piston friction is encountered thus Decrease of mechanical efficiency.

Discussion

38.	The Principle used to dissipate the heat from water to atmosphere via Radiator in the sequence is ______and ______(a) radiation and Conduction(b) radiation and Convection(c) conduction and Convection(d) convection and RadiationThis question was addressed to me in an interview.Query is from Methods of Cooling topic in division Cooling System of Automotive Engine Design
Answer» Correct choice is (c) conduction and CONVECTION To explain: Conduction occurs when the engine gets heated up and the heat is transferred from the combustion chamber to the WATER jacket where the water absorbs the heat. Convection takes place when the water becomes dense by ABSORBING the heat and which becomes LESS dense once it is passed through the radiator.

Discussion

39.	In air-cooled small engines______ are provided on the outer perimeter of the engine?(a) Flanges(b) Fins(c) Holes(d) TreadsThe question was asked in examination.I'm obligated to ask this question of Methods of Cooling in portion Cooling System of Automotive Engine Design
Answer» The CORRECT answer is (b) Fins Easiest explanation: Fins are present on the outer PERIMETER of the engine as they INCREASE the surface AREA of contact metal with the air by doing this heat is transferred from the engine through Fins, into the atmosphere THUS achieving effective cooling is obtained.

Discussion

Explore topic-wise InterviewSolutions in .

The anti-freeze should have ______specific heat capacity to be compared to the specific heat capacity of the coolant.(a) zero(b) average(c) low(d) highThe question was posed to me during an online interview.The query is from Coolants in division Cooling System of Automotive Engine Design

The boiling point of the coolant should be ______(a) low(b) high(c) medium(d) none of the aboveThis question was addressed to me during an interview for a job.This intriguing question originated from Coolants topic in section Cooling System of Automotive Engine Design

The abbreviation of SCA is ______(a) supplemental Coolant Additive(b) super Cooling Additive(c) standard Coolant Additive(d) strategic Chemical AdditiveI got this question at a job interview.My question is based upon Coolants topic in portion Cooling System of Automotive Engine Design

The coolant used in heavy-duty engines should be______(a) green in color(b) fully formulated(c) concentrated(d) blueI have been asked this question in class test.My doubt is from Coolants topic in chapter Cooling System of Automotive Engine Design

In a 50% concentration of ethylene glycol (by volume) lowers the freezing point of water to ______Degree Centigrade.(a) -30(b) -50(c) -35(d) -37I had been asked this question at a job interview.Enquiry is from Coolants in chapter Cooling System of Automotive Engine Design

The boiling point of ethylene glycol used in the coolant is ______Degree Centigrade(a) 290(b) 195(c) 200(d) 300I had been asked this question in an interview for internship.This intriguing question originated from Coolants in section Cooling System of Automotive Engine Design

The pH range of Coolant is ______(a) equal to or Greater than 7(b) 0(c) 0-5(d) 3-6I have been asked this question in class test.Query is from Coolants topic in section Cooling System of Automotive Engine Design

The Fans consumes around ______% of the engine BP If not operated efficiently and economically.(a) 11(b) 5(c) 6(d) 10This question was posed to me in semester exam.I need to ask this question from Components of Water Cooling System in chapter Cooling System of Automotive Engine Design

The ratio of Ethylene glycol and Water in the coolant is ______(a) 50:50(b) 10:90(c) 30:70(d) 20:80I have been asked this question during a job interview.I would like to ask this question from Coolants in chapter Cooling System of Automotive Engine Design

The material used in the manufacturing of Fans in the cooling system is ______(a) cast iron(b) brass(c) plastic(d) bronzeThis question was addressed to me in a national level competition.My enquiry is from Components of Water Cooling System in chapter Cooling System of Automotive Engine Design

For the reduction of noise, the blades are spaced ______ sometimes.(a) evenly(b) unevenly(c) clockwise(d) anti-ClockwiseThe question was posed to me during an internship interview.My doubt stems from Components of Water Cooling System in section Cooling System of Automotive Engine Design

The core material used in the preparation of the radiator core is ______(a) brass(b) steel(c) plastic(d) cast ironI got this question in class test.My question is taken from Components of Water Cooling System topic in section Cooling System of Automotive Engine Design

______ valves Operates to avoid the collapse of the radiator.(a) pressure(b) inlet(c) outlet(d) vacuumI got this question in unit test.Origin of the question is Components of Water Cooling System in division Cooling System of Automotive Engine Design

For the proper maintenance _____number of years is recommended for the Flush of the Cooling System?(a) 5(b) 3(c) 2(d) 1I got this question in an interview.I'm obligated to ask this question of Methods of Cooling in portion Cooling System of Automotive Engine Design

Which of the following is absent in the air-Cooled Engine?(a) Radiator(b) Fins(c) Inlet and Exhaust port(d) Cylinder HeadI had been asked this question in exam.My query is from Methods of Cooling topic in section Cooling System of Automotive Engine Design

The position of the cooling Fan is_____ of the Radiator?(a) behind(b) top(c) bottom(d) in frontI got this question in an interview for job.Question is taken from Methods of Cooling in portion Cooling System of Automotive Engine Design

_____ Type of Wear takes places in the water Jackets of water-cooled engines?(a) mechanical(b) adhesion(c) abrasion(d) corrosionI have been asked this question in an international level competition.The doubt is from Methods of Cooling topic in section Cooling System of Automotive Engine Design

The main difference between the Pump circulation System and Thermosyphon System is the presence of ______(a) fan(b) radiator(c) hosepipe(d) pumpThe question was posed to me during an online interview.The doubt is from Methods of Cooling topic in chapter Cooling System of Automotive Engine Design

In air-cooled small engines______ are provided on the outer perimeter of the engine?(a) Flanges(b) Fins(c) Holes(d) TreadsThe question was asked in examination.I'm obligated to ask this question of Methods of Cooling in portion Cooling System of Automotive Engine Design