Automobile Engines — Summer 2022

What are the assumptions made for fuel-air cycles?

Give the comparison between wet sump and dry sump lubrication system.

Explain MPFI system for S.I. engine.

Explain the following terms:

Rich Mixture (ii) Ignition limit (iii) Stochiometric mixture

What is meant by supercharging? What is its effect on engine performance?

Derive an equation for the variation in air standard efficiency of otto cycle on account of variation in C . v

Asingle cylinder 4 – stroke cycle oil engine works on diesel cycle. The following readings were recorded during trial on full load: Area of indicator = 3 cm2, Length of the diagram = 4 cm, Spring constant = 10 bar/cm2-cm, Speed of the engine = 400 rpm, Load on the brake = 380 N, Spring reading = 50 N, Diameter of the brake drum = 120 cm, Fuel consumption = 2.8 kg/hr, Calorific value of fuel = 42000 kJ/kg, Diameter of the cylinder = 16 cm, Stroke of the piston = 20 cm. Find:- (i) F.P. of the engine, (ii) Mechanical efficiency, (iii) Brake thermal efficiency, (iv) Brake mean effective pressure.

What are the different parameters considered to control the knock?

Describe the Pintle and Pintaux nozzle with neat sketch and discuss their relative merits and demerits.

Draw and explain valve timing diagram of 4-storke petrol engine

State the factors on which delay period depends in C.I. engine

Explain the effect of fuel-air ratio on fuel air cycle analyses.

State the different methods used for I. C. Engine cooling and Explain thermo-syphon cooling system.

What are the limitations of simple carburettor?

With a line diagram, explain the working of pneumatic governor.

What is turbocharging? State the types of turbocharging and explain any one with neat sketch. OR1

What are the different factors that affect the ignition lag S.I. engine combustion?

Explain the function of following parts in simple carburettor:

Chock valve, (ii) Throttle valve, (iii) Float and float chamber, (iv) Nozzle tip

With a line diagram explain the working of common rail fuel injection system used in C. I. Engine.

Why rich mixture required for starting and during idling of an engine?

Describe the different phases of Spray formation with neat sketch

A 4- cylinder, 4 – stroke petrol engine 6 cm bore and 9 cm stroke was tested at constant speed. The fuel supply was fixed to 0.13 kg/min and plugs of 4-cylinder were successively short-circuited without change of speed. The power measurement were as follows: With all cylinder working = 16.25 kW, With No. of 1st cylinder cut-off=11.55 kW, With No. of 2nd cylinder cut-off=11.65 kW (B.P.), With No. of 3rd cylinder cut-off=11.70 kW (B.P.), With No. of 4th cylinder cut-off=11.50 kW (B.P.). Find:- (i) I.P. of engine, (ii) Mechanical efficiency, (iii) Indicated thermal efficiency, if C.V. of fuel used is 42000kJ/kg, (iv) Relative efficiency on I.P. basis assuming clearance volume 65 cm3.

State the function of lubrication system in I. C. engine

Explain detonation or Knocking in S.I. engine

Explain construction and working of bosch fuel pump