Differentiate SI and CI engines.
[3 marks]Compare the properties of petrol and diesel with unconventional fuels.
[4 marks]Asingle cylinder, 4-stroke diesel engine having swept volume of 850 cm3 is tested at 300 rpm. When the braking torque of 50 Nm is applied, analysis of indicator diagram gives a mean effective pressure of 10 bar. Find the brake power and mechanical efficiency of the engine.
[7 marks]Explain the working principle of exhaust gas calorimeter.
[3 marks]Explain the orifice-chamber method for air consumption measurement in IC engine with neat sketch.
[4 marks]A 4 cylinder 4-stroke SI engine of 60 mm bore and 90 mm 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 measurements were as follows: BP with all cylinder working = 16.25 kW; BP with cylinder 1 cut-off = 11.55 kW; BP with cylinder 2 cut-off = 11.65 kW; BP. with cylinder 3 cut-off = 11.70 kW; BP with cylinder 4 cut-off = 11.50 kW. The calorific value of fuel is 42 MJ/kg. Find Indicated thermal efficiency of the engine and compare it with air standard efficiency. The clearance volume of one cylinder is taken as 50 cm3.
[7 marks]The following observations are made during a trail on an oil engine. (1) Motor power to start the engine = 10 kW (2) R.P.M =1800 (3) Brake torque = 345 Nm (4) Fuel used = 16 kg/hour (5) C.V. of fuel used = 42 MJ/kg (6) Air supplied = 4.85 kg/min (7) Quantity of cooling water = 17 kg/min (8) Outlet temperature of cooling water = 68 0C (9) Room temperature = 21 0C (10) Exhaust gas temperature = 400 0C. Take C = pw 4.2 KJ/kg. Kand C = 1.25 KJ/kg.K. pg Determine (a) B.P. (b) Mechanical efficiency (c) bsfc and (d) draw a heat balance sheet on kW basis and percentage basis.
[7 marks]Define the following terms: (1) Ignition lag (2) Highest useful compression ratio (HUCR) (3) Performance number
[3 marks]Explain the effects of knocking in SI engines in details.
[4 marks]Explain the stages of combustion in CI engine using P-Ɵ (pressure-crank angle) diagram in details.
[7 marks]Differentiate knocking in SI and CI engines.
[3 marks]Explain the Lanova air-cell combustion chamber with neat sketch.
[4 marks]Enlist various design consideration parameters for good combustion chambers. Also explain any one modern combustion chamber used in SI engine with neat sketch.
[7 marks]Enlist the functions of lubrication system. Designate the lubricating oil grade: SAE 20W/40.
[3 marks]Differentiate air cooling and water-cooling system in details.
[4 marks]Differentiate supercharging and turbocharging in details.
[7 marks]Define EURO-III and EURO-IV emission norms.
[3 marks]Explain the working principle of stratified charge engine with neat sketch.
[4 marks]Explain pressure feed lubrication system with neat sketch.
[7 marks]Give the functions of following parts of simple carburetor. (1) Venturi (2) Float and float chamber (3) chock valve
[3 marks]Explain the compensating or double jet with neat sketch.
[4 marks]Enlist various types of nozzles used in CI engine. Also explain the Individual pump system with neat sketch.
[7 marks]Enlist the requirements of ideal injection system.
[3 marks]Write the chemically correct combustion equation for octane and define the practical A:F (air-fuel ratio) limit for SI engine.
[4 marks]Explain the following terms in details: (1) Ice formation (2) Vapour lock (3) Back-firing
[7 marks]