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Question
why we are using oil with petrol in two stroke engines but
not in four stroke engines(two wheelers)?................
 Question Submitted By :: L.raghuraman15
I also faced this Question!!     Rank Answer Posted By  
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 1
With rare exceptions, 4-stroke engines run at substantially
slower rpms than a comparable 2-stroke engine…most in the
under-10,000 rpm range vs. 12,000, 13,000 or more for a
typical 2-stroke of the same size. They are engineered to
deliver maximum power at slower rpms, with bigger props.
What does this have to do with it? One of the main factors
used in determining the proper oil content of fuel is heat.
To use the well-worn term, it doesn’t take a rocket
scientist to figure out that the more slowly an engine
turns, the less heat it generates from friction. If you
don’t believe that, rub your palms together slowly, then as
fast as you can.




So….lower rpms = less heat = less need for oil.
 
Is This Answer Correct ?    29 Yes 50 No
Gautham
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 2
It is just becuase in two stroke petrol engines the
crankcase is used to pressurized the Air Fuel mixture into
the combusting chamber and therefore if using the wet sump
system the combustion chamber will be filled with oil and
the spark plug will be coverd by burned oil that is why the
dry sump systerm is used.
 
Is This Answer Correct ?    22 Yes 30 No
Enoch Akot
 
 
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 3
we use oil because there is no lubrication facility in case
of two stroke engines as they are double acting and the
fuel has to be mixed in the lubricating oil but in case of
4 stroke engines,they are separated by the moving piston.
 
Is This Answer Correct ?    69 Yes 5 No
Parneet Singh
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 4
2 stroke is much simpler machanism. It has inlet and
exhaust ports. There is no valve mechanism as in the 4
stroke engine. So lubrication in 2 stroke is much simpler
and just add oil into the petrol for lubricating the moving
parts like piston assy. Whereas 4 stroke requires more
machanism and seperate lubrication system.
 
Is This Answer Correct ?    16 Yes 10 No
Krishna Kumar
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 5
two stroke engine does not have inlet and outlet valve
mechanism,so we need to lubricate more parts in four stroke
engine. thats why four stroke engine cannot be lubricated
by mixing oil with petrol.
 
Is This Answer Correct ?    3 Yes 22 No
Krish
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 6
in two stroke more heat is generated. in order to reduce
heat generation lubrication is needed.there is two power
cycles in when compared to 4 stroke ,more lubrication is
needed.this is the main drawback of 2 stroke .
 
Is This Answer Correct ?    1 Yes 7 No
Hariharan
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 7
We are using oil with petrol in two stroke engine because
their are no force feed system to lubrication the
component.Two stroke engine have no inlet and exhaust valve
so no need of lubrication for cylinder head. the air/fuel
mixture follow via crankcase we need to lubricate only
crankcase ( cylinder wall, connecting rod, piston pin etc.)
 
Is This Answer Correct ?    1 Yes 3 No
Naveen Rohilla
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 8
2 stroke engine lack a dedicated cooling system as in 4 strake engine. the crankcase of 2 stroke engine doesnot contain lubricating oil.

As the mixture of oil and petrol reaches crankcase in 2 stroke ,the petrol gets vaporised and transferred to cylinder for combustion leaving the oil lubricating the parts of crankcase.
The connecting rod uses a roller bearing which requires less lubrication .
 
Is This Answer Correct ?    3 Yes 0 No
Ptm
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 9
In a 4 stroke engine, we have a dedicated system for lubrication. We have lubricating ports which supply the lubricating oil from the sump so that all the parts are thoroughly cooled. But, most small petrol two-stroke engines cannot be lubricated by oil contained in their crankcase and sump, since the crankcase is already being used to pump fuel-air mixture into the cylinder. So while fueling, we mix gasoline with an oil to be distributed throughout the engine for lubrication. The two-stroke oil is ultimately burned along with the fuel. But i=this can contribute to more smoke and distinctive odor. 
Is This Answer Correct ?    4 Yes 0 No
Rv
 
  Re: why we are using oil with petrol in two stroke engines but not in four stroke engines(two wheelers)?................
Answer
# 10
becoz in two stoke engine to provide lubricant in engine .
there is only way to get inside it .

 
Is This Answer Correct ?    1 Yes 0 No
Govindsharma Auto-mobile 2nd Y
 

 
 
 
Other Automobile Engineering Interview Questions
 
  Question Asked @ Answers
 
types of wheels preffered in sports cars ? Nissan 2
Why do you want to change your present company??   5
During a turn , why does the inner Tyre experience greater resistance to turning than the outer Tyre? Mahindra 2
1. What are good characteristics of good combustion in a boiler? 2. What do you analyze from boiler water analysis? 3. What do you treat in high alkalinity of boiler water? 4. What is a feed water pump? Dearator feed heater? 5. What is the purpose of the nozzle of impulse turbine? 6. What are the things needed to have an efficient boiler burning? 7. Name Of Parts And Each Purpose 8. What are the causes of emergency stop in a steam engine? 9. What is the normal vacuum pressure in a steam turbine atmospheric condenser? What would cause the press to falls? 10. Steam turbine (function an parts) 11. What is the boiling point of water? 12. What are the safety devices of boiler? 13. What is the effect of high alkaline water to a boiler? 14. Steps In starting boilers. 15. Small gear found in the steam turbine. 16. What is an Economizer? 17. What are the methods of heat transfer? 18. Types of pressure 19. What are the different parts of impulse reaction turbine? 20. What is the color of the flame of the boiler running in good condition? 21. What type of pump is commonly used is feed water system in auxiliary boiler? 22. What is the specific heat of water? 23. What do you do to prevent flare black? 24. What is a brake horsepower? 25. What is the purpose of a de-superheater? 26. What is the purpose of corrugated furnaces? 27. What are the causes of steam turbine failure? 28. What is the purpose of superheater? 29. Given a cutaway isometric view of the steam turbine. Examinee was asked to identify the following Parts: 30. What is thrust bearing? 31. Give five boiler mounting valves. 32. In steam boiler, what are the various test in water boiler? 33. How much calorific value of heat is needed to heat 00c of 34. What will happen if boiler backfires? 35. What is the color of flame if the boiler is running in good condition? How about when it is not in good condition? 36. How does the steam work in a steam turbine? 37. What are the causes of boiler backfire and steps in how to prevent it from happening? 38. What are the causes of high alkalinity in boiler water? 39. What are sensible heat, latent heat, and specific heat of water? 40. What are the causes of turbine vibration 41. Identify the parts of steam turbine 42. What is the normal Ph value of boiler water 43. Causes of dilution of lubricating oil in a steam turbine? 44. Explain briefly- good combustion of auxiliary boiler? 45. Method of testing or checking boiler water? 46. What is mean carry over of Aux. Boiler? 47. What are steam turbine parts usually come into damage? 48. Why must we pay attention when we drain steam in steam turbine. What factors are observed? 49. What type of pump use in boiler F.O. system? 50. What parameters to be reported when we send lubricating oil for shore analysis? 51. In boiler, what does steam and smoke goes out to the funnel. What reason? 52. Where can you find the feed check valve and feed stop valve and give the purpose of it? 53. What are the causes of troubles in boiler during operations? 54. Give the purpose of nozzle in impulse turbine? 55. What s gland sealing steam? 56. How to prevent back fire of boiler? 57. What is the used of economizer in boiler? 58. What is the seal packing gland for turbine? 59. What is the flow of steam in an impulse turbine? 60. What will happen if you blow the soot in the boiler? 61. State the purpose of air heater? 62. How to operate soot blower boiler and economizer? 63. What do you mean by A.CC.? 64. What is the thermal efficiency of a diesel engine? 65. What is a blow down valves? RRB 1
Overview of working of commen rail injection system in cars? Skoda 3
1) A mechanism which enables the rotary motion of one shaft to another shaft at the same axis is called a) Gear box b) Differential c) Clutch d) Flywheel 2) The main advantage of a good clutch is a) Good torque transmission b) Rapid engagement c) Large size d) High inertia 3) Hard shifting of gears would result when a) There is rapid engagement of gears b) There is less heat dissipation c) The clutch inertia is very high d) There is no clutch free pedal play 4) The torque transmitted by a clutch is given by a) T = μWR b) T = μ/WR c) T = μW/R d) T = 1/μWR 5) The coefficient of friction for the Asbestos-based materials used for clutch facing is a) 0.07 b) 0.17 c) 0.27 d) 0.37 6) The maximum amount of axial load to be applied on a clutch plate is a) 100 KN b) 200 KN c) 300 KN d) 400 KN 7) Mean effective radius of contact surfaces of a clutch plate is decided by a) Coefficient of friction b) Axial pressure c) Space available in the vehicle d) Amount of torque to be transmitted 8) Axial force to keep the clutch in engaged position is provided by a) Springs arranged circumferentially b) Pressure plate c) Flywheel d) Clutch pedal 9) The friction plate is always mounted on a) flywheel b) Pressure plate c) Internally splined hub d) Clutch spring 10) The main advantage of single plate clutch over cone clutch is a) Easier gear changing b) Less binding of contact surfaces c) Less pedal movement d) all of the above 11) The main function of transmission is a) To provide means to vary the torque ratio between the engine and the road wheels b) To provide neutral position c) To provide means to back the car d) all of the above 12) The resistance to the vehicle motion whose magnitude remain constant with respect to the vehicle speed is a) Resistance due to gradient b) Resistance due to the road c) Resistance due to the tyre friction d) all of the above 13) The resistance to the vehicle motion whose magnitude various with the square of the vehicle speed is a) Resistance due to gradient b) Resistance due to road c) Resistance due to the tyre friction d) Resistance due to wind 14) If the tractive effort is the highest for a given velocity, then the vehicle must be in a) Top gear b) Third gear c) Second gear d) First gear 15) The point of interaction of the tractive effort curve and the total resistance curve is called a) Stabilizing speed point b) Low speed point c) High speed point d) Normal speed point 16) If the given tractive effort curve and the total resistance curve does not intersect, then a) The vehicle will accelerate b) The vehicle will decelerate c) The vehicle will not be able to go at this gradient for the given gear d) None of the above 17) The main disadvantage of sliding mesh type of gear box is a) High noise level b) Low mechanical efficiency c) High skill required by the driver d) all of the above 18) Double declutching is used for the engagement of gears in a) Sliding mesh type of gear box b) Constant mesh type of gear box c) Synchromesh type of gear box d) None of the above 19) High speed gear is obtained in the case of sliding mesh gear box when a) Motion is transferred through the clutch gear to lay shaft gear b) Main shaft is coupled to the clutch shaft c) Smallest gear on the lay shaft is engaged d) Largest gear on the lay shaft is engaged 20) The Figure 1 depicts a) Top gear b) Second gear c) First gear d) Reverse gear 21) In case of a constant mesh gear box, when the left dog clutch is slid to the left by means of the selector mechanism, a) Direct gear is obtained b) First gear is obtained c) Second gear is obtained d) Reverse gear is obtained 22) In a constant mesh gear box, when the right dog clutch is engaged with the gear on the right side of the main shaft, a) Direct gear is obtained b) First gear is obtained c) Second gear is obtained d) Reverse gear is obtained 23) Double declutching is required in constant mesh gear box a) To equalize the speed of main shaft gear and the sliding dog b) To provide direct gear c) To equalize the speed of countershaft gear and the sliding dog d) None of the above 24) The number of spring loaded balls provided circumferentially in a synchromesh gear box is a) 3 b) 4 c) 5 d) 6 25) In a synchromesh device, when members G1 and F1 are slid to left and cones M1 and M2 are in contact, a) Direct gear is obtained b) Second gear is obtained c) Third gear is obtained d) Reverse gear is obtained 26) For the second gear in a synchromesh system, the drive transfer will be through a) U1, U2, C, F2, and splines b) U1, U2, C, F1, and splines c) U1, U3, D, F3, and splines d) U1, U4, U5, E, F2, and splines 27) Interlocking mechanism is provided in the gear box cover a) To prevent engagement of two gears simultaneously b) To prevent engagement of reverse gear c) To facilitate the gear selection d) To avoid the necessity of having neutral gear 28) Stiff spring is used in the selector mechanism a) To prevent engagement of two gears simultaneously b) To prevent engagement of reverse gear c) To facilitate the gear selection d) To avoid the necessity of having neutral gear 29) Propeller shaft is used for the purpose of a) Transmitting the drive from the transmission to the bevel pinion of the final drive b) Transmitting the drive from the crankshaft to the road wheels c) Transmitting the drive from the transmission to the road wheels d) Transmitting the drive from the crankshaft to the bevel pinion of the final drive 30) Slip joints are provided in the propeller shaft a) To adjust the inclination of the propeller shaft b) To adjust the length of the propeller shaft c) To prevent the whirling of the propeller shaft d) To adjust the up and down movement of the rear axle 31) If two shafts used for transfer of drive are inclined to each other, then a) Slip joint is used b) Flange coupling is used c) Universal joint is used d) None of the above 32) The Hook’s joint works efficiently when the propeller shaft inclination is a) 18o b) 28o c) 38o d) 48o 33) The number of arms provided to the Cross of the Hook’s joint is a) 1 b) 2 c) 3 d) 4 34) The function of the final drive is to a) Provide a permanent speed reduction b) To turn the drive round through 90o c) To provide drive to the rear wheels d) all of the above 35) The permanent reduction provided by the final drive in car is a) 4:1 b) 6:1 c) 8:1 d) 10:1 36) The permanent reduction provided by the final drive in heavy vehicle is a) 4:1 b) 6:1 c) 8:1 d) 10:1 37) Single reduction is used in final drive when it is about a) 6:1 b) 8:1 c) 10:1 d) 12:1 38) The function of Differential is a) To prevent wheel skidding b) To reduce the speed of the inner wheels during turning c) To keep the speed of all the wheels same when going straight ahead d) all of the above 39) The crown wheel of the final drive is connected to a) Cage b) Spider c) Cross pin d) Axle half shaft 40) In a vehicle, which is going straight ahead at N rpm, if the left wheel rotates forward at n rpm, then the resultant speed of the right wheel will be a) N+n b) N-n c) N/n d) Nn Bosch 2
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