The pressure and temperature at the end of compression stroke in a petrol engine are of the order ofДў1.

(c) opens at 10В° after top dead center and closes 20В° before the bottom dead centerДў0. (b) opens at top dead center and closes at bottom dead center (a) opens at 20В° before top dead center and closes at 35В° after the bottom dead center In a typical medium speed 4-stroke cycle diesel engine the inlet valve In case of gas turbines, the gaseous fuel consumption guarantees are based onДЎ9. If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the %age increase in efficiency will beДЎ8. An engine indicator is used to determine the followingДЎ4. The calorific value of gaseous fuels is expressed in terms ofДЎ1.

(d) more or less depending on power ratingД©. The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is (c) ratio of pressure after compression and before compressionДЁ. (b) volume displaced by piston per stroke and clearance volume in cylinder (a) the ratio of volumes of air in cylinder before compression stroke and after compression stroke The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged ?Д¦. (d) supplying compressed air to remove combustion products fullyДҐ. (c) injecting excess fuel for raising more load (a) supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere (d) air used for forcing burnt gases out of engineвЂ™s cylinder during the exhaust period (c) burnt air containing products of combustion (a) air used for combustion sent under pres-sure (c) heat resulting from compressing air that is supplied for combustion In a diesel engine, the fuel is ignited by The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaftДў. Engine Multiple Choice Questions and AnswersДЎ. Engine MCQs to score good rank in various Entrance and Placement Exams. These Top 250 Internal Combustion Objective Questions and Answers are very important for the Competitive Exams like IES, GATE, PSU inВ Mechanical Engineering Branch. Engine Multiple Choice Questions and Answers for Mechanical Engineering is given below. Pay attention to piston position, valve position, the moment when the ignition occurs and the succession of the strokes.Here is a list ofВ Top 250 I.C. In the animation below you can see clearly how the internal combustion engine works. The linear motion of the piston is transformed into rotational motion of the crankshaft through the connecting rod.ДЇor a better understanding, weвЂ™re summarising the piston initial position, valve position and energy balance for each stroke. The only stroke which produces torque (energy) is the power stroke, all the others are consuming energy. This means that one engine cycles takes twoВ complete rotations of the crankshaft (720В°). The movement of the piston from the BDC towards the TDC pushes most of the exhaust gases out of the cylinder, into the exhaust pipes.Дuring the exhaustВ stroke, the engine consumes energy (the crankshaft is rotating due to the inertia of the components).ДЄs you can see, in order to have a complete combustion (engine) cycle the piston has to perform 4 strokes. During this stroke, the exhaust valve is open. The exhaust stroke starts with the piston at the BDC, after the power stroke finished. Internal combustion engine exhaust stroke In the figure below weвЂ™ll have a look at the main moving part of an ICE, which transform the gas pressure within the cylinder in mechanical power.

cylinder head, cylinder block) and some of them are moving. In Figure 1 we can examine the complete set of mechanical components of an ICE. The combustion chamber is the volume created between piston, cylinder head and engine block when the piston is close to TDC. The piston moves inside the cylinder from BDC to TDC. As for the cylinder head, through the engine block flows coolant to help controlВ the temperature of the engine. Inside the engine block (12) we can find the piston, connecting rod and crankshaft. The cylinder head (8) usually contains the camshaft(s), valves, valve buckets, valve return springs, spark/glow plugs and injectors (for direct injection engines).В Through the cylinder head flows the cooling liquid of the engine. Image: Internal combustion engine (DOHC) parts

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