AUTOMOTIVE ENGINES
QUESTIONS FROM UNIVERSITY EXAM
Semester:
III Max.
Marks: 100
PART – A (10 x 2 = 20 marks)
- What is the use of air standard cycle?
- Draw the Otto cycle on P-V diagram
- what are the firing order used in 4 and 6 cylinder engines
- what is stiochiometric air fuel ratio
- what are the three basic types of carburetors
- what are the different methods of engine cooling
- what is blow by
- what is flame front
- what are the various types of combustion chambers used in SI engines
- what is scvangening efficiency
- what is short circuiting
- what is carnot cycle and its importance
- What are different air fuel mixtures on which an engine can operate
- Write down the firing order for four and six cylinder engines
- what is indicator diagram
- what is the necessity of firing order in a multicylinder engines
- what are the mixture limits for inflammability
- what is the difference between a constant choke carburetor and a constant vacuum carburetor
- what is a thermostat
- what is the need for providing crankcase ventilation
- what are the variable s that affect the knock of SI engines
- How is the location of the spark plug can influence knocking tendency
- why scavenging is important in two stroke engines compared to four stroke engines
- Define trapping efficiency
- List the different types of ignition system used in vehicles
- What is the use of condenser in ignition system
- What are the main functions of air injection pump?
- What is meant by crank case ventilation?
- Write the reason for cooling an engine
- what is the advantage of air cooling system
- what is meant by abnormal combustion
- What is delay period and what are the factors that affect the delay period?
- Define enthalpy
- Write down the components of ignition system used in automobiles
- Write down the possible faults in conventional ignition system
- Draw the diagram for an ignition coil and name the components
- Write any four advantage of 4 stroke petrol engine over 2 stroke petrol engine
- write the air standard efficiency of an Otto cycle
- write ant four factor that affects the process of combustion
- what are the various requirement of good carburetor
- what is the main function of an spark plug
- write different methods of SI lubricating system
- write the reason for cooling an engine
- what is meant by abnormal combustion
- What is a homogeneous and heterogeneous mixture?
- what is opposed piston engine
- Define dwell angle and mention its importance
- Briefly explain about two types of spark plug used in automobiles
- List the advantage of Electronic ignition system with conventional type
- Write down the firing order for four and six cylinder engines
- List the different types of ignition system used in vehicles
- What is the use of condenser in ignition system
- Write down the components of ignition system used in automobiles
- Write down the possible faults in conventional ignition system
PART – B
(16 x 2 = 32 marks)
- Compare four stroke and two stroke cycle engines and bring out their relative merits and demerits
- Describe with suitables sketches the idling system and accelerating pump of a modern carburetor
- sketch a mechanical fuel pump and describe its working
- Explain with a neat sketch the forced circulation cooling system
- Discuss the different properties of lubricants
- Discuss the design criteria for a S.I engine combustion chamber
- Explain with neat sketches the two different types of two stroke engines
- Explain the various scavenging pumps used in a two stroke engines
- Discuss the two stroke engine construction and operation with neat sketches
- with a neat sketch explain the working principles of a simple carburetor
- Explain briefly the electronic fuel injection system used in some modern cars
- Explain with neat sketches the thermosypon cooling system and pressure cooling system
- Discuss the various types of combustion chambers used in SI engines
- Explain with a graph the three possible theoretical scvangening processes
- Explain with neat sketch the cross flow scvangening and uniflow scvangening
- Briefly explain the principle of four stroke petrol engine with a simple sketch
- Draw the ideal and actual indicator diagram for a four stroke petrol engine and explain why they differ each other.
- Draw the sketch of a downdraught carburetor. How do the idle and low speed circuits work in this carburetor
- Briefly explain the working principle of line fuel injection pump
- Explain the dry sump lubricating system with neat sketch
- What is an air cooling system and in which type of engine it is normally used.
- Explain the desirable properties of a good lubricant
- What are the various types of combustion chamber used in SI engines? explain them briefly
- Write any one type of scavenging pump used in a 2 stroke petrol engine and explain briefly.
- Define the following
i)
Delivery ratio
ii)
Trapping efficiency
iii)
Relative cylinder charge
iv)
Scavenging efficiency
- A gas working on the Otto cycle has a cylinder of diameter 200 mm and stroke 250 m. The clearance volume is 1570 CC. Find the air standard efficiency. Assue Cp= 1.004 KJ/kg K and Cv = 0.7171 KJ/kg K for air.
- With a suitable sketches explain the various modern automobiles carburetors
- Give brief account of the injection in SI engine
- Clearly explain the various Wet sump lubricating system. Compare wet sump and dry sump lubrication
- With suitable sketches explain the liquid cooling system of an Automobile.
- Explain the phenomenon of knock in SI engine and compare with it with CI engines
- Explain various scavenging pumps used in a two stroke engines
- what are the advantage and disadvantage of 2 stroke engine
- Explain with figures various types of combustion chambers used in SI engines.
- With the aid of a circuit diagram explain the working principles of a battery coil ignition system.
- Describe the working principles of a centrifugal spark advance mechanism with
neat diagram
- Describe the necessity of the spark advance mechanism in an engine
- With the aid of a diagram describe vacuum spark advance mechanism
- Draw the diagram for an ignition coil and name the components
- With the aid of a circuit diagram explain the working principles of a battery coil ignition system.
- Describe the working principles of a centrifugal spark advance mechanism with
neat diagram
97. Describe the
necessity of the spark advance mechanism in an engine
98. With the aid
of a diagram describe vacuum spark advance mechanism
