GOVERNMENT ENGINEERING COLLEGE, VALSAD MECHANICAL ENGINEERING DEPARTMENT CERTIFICATE This is to certify that Mr./Miss_____________________________________________________ of Mechanical Branch, Sem-VII, Enrollment No.__________________________, has satisfactorily completed his/her term work for the Internal Combustion Engine (2161902) during odd term-20____. Date : Sign of Faculty Head of the Department GOVERNMENT ENGINEERING COLLEGE, VALSAD MECHANICAL ENGINEERING DEPARTMENT INDEX Subject: Internal Combustion Engine (2161902) PRACTICAL SIGN OF TITLE GRADE DATE NO. FACULTY TO DETERMINE VALVE TIMINGS OF FOUR STROKES PETROL /DIESEL ENGINE & PORT 1 TIMING OF TWO STROKES PETROL/DIESEL ENGINE. TO STUDY ABOUT IGNITION SYSTEM OF I.C. 2 ENGINE. TO STUDY ABOUT SUPERCHARGING AND TURBO 3 CHARGING OF I.C.ENGINE. TO STUDY EXPERIMENTAL PRODUCER & DATA 4 CALCUTION FOR THE ENGINE. TO STUDY ABOUT ENGINE EMISSIONS AND THEIR 5 CONTROL. TO DETERMINE THE PERFORMANCE OF SINGLE 6 CYLINDER, FOUR STROKE, DIESEL ENGINE. TO DETERMINE THE PERFORMANCE OF FOUR 7 CYLINDER, FOUR STROKE, PETROL ENGINE. TO PERFORM MORSE TEST OF FOUR CYLINDERS, 8 FOUR STROKES, PETROL ENGINE WITH ELECTRICAL DYNAMOMETER. TO PERFORM WILLAN’S LINE METHOD FOR 9 DIESEL ENGINE. TO STUDY FUEL SUPPLY SYSTEM OF ENGINES. 10 GOVERNMENT ENGINEERING COLLEGE, VALSAD MECHANICAL ENGINEERING DEPARTMENT PRACTICAL 1: TO DETERMINE VALVE TIMINGS OF FOUR STROKES PETROL /DIESEL ENGINE & PORT TIMING OF TWO STROKES PETROL/DIESEL ENGINE. INTERNAL COMBUSTION ENGINE (2161902) B.E. SEM –6th OBJECTIVES: To understand the basic functional relation between cam and crank timing. To understand valve timing and port timing of engine. To determine valve timing diagram of four stroke engine and port timing diagram of two stroke. THEORY: INTRODUCTION Theoretically the inlet valve is opened during the suction stroke and the exhaust valve during the exhaust stroke. In actual practice the valves do not open and close exactly when the piston at dead centre position. The inlet valve opens a little before the end of exhaust stroke and continues to the initial part of compression stroke. Similarly the exhaust valve opens a little before the end of expansion process and continues to the initial part of suction stroke. There is a small duration of time when both the suction and exhaust are open simultaneously. PROCEDURE:- To determine the correct direction of rotation of the engine, flywheel is turn by hand in either direction and by observing the cams; the direction which gives the proper sequence of operations (four strokes) is found out. The next thing is to find cut the position of flywheel, against a pointer fixed near it when the piston is a dead centre position as the crank is perfectly horizontal. Keeping the crank inclined to horizontal by a small angle a chalk mark is made on the piston against the cylinder liner as well as on the flywheel periphery against the pointer. The engine is turned in correct direction of rotation so that after passing through the dead centre position the piston is brought to its original position and a mark is made on the flywheel, against the pointer. It can be seen that the mode point mark is made on the flywheel gives the required position of the piston at outer dead centre (I.D.C). Then for finding out the opening and closing of inlet valve the engine is turned round slowly. When the roller connected to the suction valve just comes in contact with the cam, a mark is made on the flywheel against the pointer. This point gives the position for the beginning of opening of the inlet valve. The flywheel is further rotated and a mark is made on it, when the cam just leaves contact with the roller, indicating closing of the inlet valve. INTERNAL COMBUSTION ENGINE Prepared By- Dr. Manish K. Mistry For finding out the opening and closing of the exhaust valve, the same procedure is followed, this time by observing the exhaust valve roller. To determine the fuel injection time, the injector is removed from the cylinder, turning the flywheel by hand, the moment, the fuel is seen issuing out of injector, and a mark is made on the flywheel. The circumferential distances of those marks from the corresponding dead center position marked on the crank are calculated and the valve timing diagram is drawn. Valve timing diagram of 4- stroke single cylinder diesel engine IVO - 250 before TDC IVC - 300 after BDC EVO - 450 before BDC EVC - 150 after TDC FVO - 150 before TDC FVC - 250 after TD Valve timing diagram of 4- stroke single cylinder petrol engine.(low speed) IVO - 100 before TDC IVC - 200 after BDC EVO - 250 before BDC EVC - 50 after TDC Valve timing diagram of 4- stroke single cylinder petrol engine.(high speed) IVO - 100 before TDC IVC - 500 after BDC EVO - 450 before BDC EVC - 200 after TDC Port timing diagram of 4- stroke single cylinder petrol engine EPO - 450 before TDC EPC - 450 after BDC TPO - 350 before BDC TPC - 350 after TDC INTERNAL COMBUSTION ENGINE Prepared By- Dr. Manish K. Mistry GOVERNMENT ENGINEERING COLLEGE, VALSAD MECHANICAL ENGINEERING DEPARTMENT PRACTICAL 2: TO STUDY ABOUT IGNITION SYSTEM OF I C ENGINES. INTERNAL COMBUSTION ENGINE (2161902) B.E. SEM –6th OBJECTIVES: To understand the basic components of ignition system of petrol engine. To understand types of ignition system and its features. To understand working of different types of ignition system. THEORY: INTRODUCTION The ignition system carries the critical current to the spark plug where the spark carries sufficient energy to increase the temperature of surrounding charge to the ignition point at which combustion becomes self-sustaining. The spark appears at the plug gap in S.I engine just as the piston approaches the TDC of the compression stroke, when the engine is idling. At higher speed or during increased throttle operation of the engine the spark is advanced. To produce the necessary high voltage required to jump a set gap of the spark plug to produce spark in the combustion chamber for the ignition of the combustible charge at the correct time. The ignition systems are classified as follows: 1. Battery - ignition system 2. Magneto - ignition system 3. Electronic - ignition system| 1) Battery - ignition system:- The components of battery ignition system area battery, an ignition switch, an ignition coil with or without an added ballast resistor, a distributor which houses the contact breaker points, the cam , the condenser, the rotor and the advanced mechanism, a spark plug, and low & high tension wirings. There are two circuits of the ignition system; (1) The Primary Circuit and (2) The Secondary circuit. The primary circuit consists of the battery, the ignition switch, the ballast resistor, the primary coil winding, the condenser and the breaker point. The secondary circuit consists of the secondary coil winding, the distributor and the spark plug. Battery Electronic energy is provided by the storage battery. The six plate – 12 volt battery supplies a steady current for ignition, starter motor, lighting, and other electric circuits, and provides a reserve of INTERNAL COMBUSTION ENGINE Prepared By- Dr. Manish K. Mistry electricity when the current consumed by the electronic equipment exceeds that being produced by the dynamo. Ignition switch: The ignition switch is placed between the battery and the primary winding of the ignition coil. It has extra set of contacts that are used when the switch is turned past ON to START. Ballast resistor: It may be placed in a series with the primary winding of the ignition coil to regulate the primary current. At low engine speed the average current is high due to longer closer of the contact break point. It is heated up and produces more resistance with cuts down the current. Ignition coil: It is used to step up 12-volts battery to a very high voltage of 10,000 to 20,000 volts to induce an electric spark across the electrodes of the spark plug. The typical ignition coil of metal clad type consists of a primary winding of 200 to 300 turns of thick wire to provide resistance of about 1.5Ώ and the secondary winding is made of a large no of turns about 21,000 of fine enameled wire sufficiently insulated to with stand high voltages. These winding are wound upon a cylindrical soft core, and enclosed by a soft iron shell. The secondary coil is closed to the core and the primary winding is located at outside of the secondary coil. Contact breaker points: It is a mechanical device for making and breaking the primary circuit of the ignition system. it consist of a fixed metal point which is ground and another metal point attached to a movable, spring loaded insulated breaker arm. The metal used is invariably one of the hardest metals, usually tungsten and each point has a circular face of about 3mm diameter. Condenser: As the contact breaker points open, the current from the battery through the primary winding of the coil is stopped. The magnetic field is therefore collapse. The collapsing magnetic field induced current which continuous to flow in the same direction in the primary circuit and thus charges the condenser plate. This absorbs current surges back out of the condenser and towards the ignition coil, thus helping to bring about the complete collapse of the magnetic field in the coil which in turn induces a high voltage of necessary magnitude in the secondary winding. Distributor: It consist of a housing a drive shaft with breaker cam, an advance mechanism, a breaker plate with contact points and a condenser, a rotor, and a cap. The shaft is driven by the camshaft of the engine through spiral gears. It rotates at one-half of the speed of crank shaft.