Main parts of spark ignition system

1. Main parts of spark ignition system

2. Four stroke engine • INTAKE STROKE: During this stroke, the piston is moving downward and the intake valve is open. This produces a partial vacuum in the cylinder, and the air-fuel mixture rushes into the cylinder

3. Compression Stroke When the piston reaches bottom dead center (BDC) , the intake valve closes. As the crankshaft continues to rotate, it pushes up through the connecting rod on the piston. The piston is therefore pushed upward and compresses the combustible mixture in the cylinder

4. Power stroke • As the piston reaches top dead center (TDC) . • the compressed air-fuel mixture is ignited. In burning, the mixture gets very hot and tries to expand in all directions. • The pressure rises. the force produced by the expanded gases forces the piston down.

5. Exhaust stroke • After the air-fuel mixture has burned, it must be cleared from the cylinder. • This is done by opening the exhaust valve just as the power stroke is finished, and the piston starts back up on the exhaust stroke

7. Firing order • The firing order is the sequence of power delivery of each cylinder in a multi-cylinder reciprocating engine. • This lead to: smooth running, for long engine fatigue life and user comfort heavily influences crankshaft design.

9. PISTON

11. COMPONENT OF PISTON • The piston head is the top surface (closest to the cylinder head) of the piston which is subjected to tremendous forces and heat during normal engine operation. A piston pin bore is a through hole in the side of the piston perpendicular to piston travel that receives the piston pin • A piston pin is a hollow shaft that connects the small end of the connecting rod to the piston.

12. The skirt of a piston is the portion of the piston closest to the crankshaft that helps align the piston as it moves in the cylinder bore. Some skirts have profiles cut into them to reduce piston mass and to provide clearance for the rotating crankshaft counterweights. • A ring groove is a recessed area located around the perimeter of the piston that is used to retain a piston ring . Piston rings are commonly made from cast iron. Cast iron retains the integrity of its original shape under heat, load, and other dynamic forces

13. A compression ring is the piston ring located in the ring groove closest to the piston head. The compression ring seals the combustion chamber from any leakage during the combustion process • A wiper ring is the piston ring with a tapered face located in the ring groove between the compression ring and the oil ring. The wiper ring is used to further seal the combustion chamber • An oil ring is the piston ring located in the ring groove closest to the crankcase. The oil ring is used to wipe excess oil from the cylinder wall during piston movement. Excess oil is returned through ring openings to the oil reservoir in the engine block.

14. MANUFACTURING PROCESS • There are many reasons for using aluminum alloys in pistons for gasoline and diesel engines • low weight, • high thermal conductivity, • very good recycling properties. • Low expansion coefficients

15. 1-Foundry • The foundry is the beginning of the piston. At the foundry the die is prepared by heating it to operating temperature for approximately one hour. This process allows the die to readily accept the molten material when it is poured. • The material The material used is(7- 10%) silicon Content aluminum. • The dies The die used are 5 piece and three piece. These dies are made from cast iron with steel inserts for the gudgeon pin holes and the cores.

16. The process • Heating the material to 700 degrees Celsius. (above the melting point ) • This is then poured into the die through the sprue. The material is then allowed to cool • Placed into a bin of hot water. • Placed into a heat treatment plant overnight. This process tempers the casting and ensures the piston will have improved qualities.

17. 3-CNC Turning • Turning on CNC machinery. • This equipment is the most accurate and fastest available for this application with • very tight tolerances and extremely fast spindle speeds.

18. the high fatigue resistance with optimized conditions in respect to chemical composition, production and heat treatment.

19. Valve Timing Diagram

20. intake stroke: Before the stroke • The intake valve is open before the piston reaches the (TDC) by 25° To pull exhaust gases out from the cylinder After the stroke • The intake valve will remain opened till the crank rotate about 71 ° To make sure the the complete charge is entire into the cylinder • The Exhaust stroke: Before the stroke • The exhaust valve is open before the piston reach to BDC by 78° To make complete scavenging of gases from the cylinder After the stroke • The exhaust valve will remain opened till the crank rotate about 45°

21. This happened because: Using turbo charger belong to truck in small vehicle The turbo make the power is very high but the temperature also is very high so the piston and the engine is damaged Take into consideration 1-The material of component 2-The temperature at the end of power stroke 3- The pressure at the end of power stroke 4- The emission of the engine 5- Fuel consumptions

22. * The suction gas fed into the combustion chamber is compressed by a constant ratio at all times. • *Then the pressure in the combustion chamber or gas temperature at the end of the compression stroke changes depending on the pressure in the combustion chamber or gas temperature at the time of start of compression • DEVELOPMENT 1- variable compression ratio mechanism 2- variable valve timing mechanism able to control a closing timing of a an intake valve

23. And that leads to • that an amount of intake air in accordance with the required load is fed into a combustion chamber • the temperature of the gas • pressure in the combustion chamber • the density of gas in the combustion • at the end of the compression stroke becomes substantially constant under substantially the same engine speed regardless of the engine load.

25. CRANK SHAFT

27. The crankshaft • sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation. • Main Journals:The crankshaft's main journals are the highly polished surfaces located at the center of the shaft. The rotation axis of the crankshaft runs through the center point of the main journals. • Rod Journals:The rod journals are highly polished surfaces to which the connecting rods attach. They circle around the crankshaft's axis of rotation.

28. Counterweights:Counterweights balance the crankshaft. • these are typically cast as part of the crankshaft but, occasionally, are bolt-on pieces • smoother running engine and allows higher RPMs to be reached. • Crank nose:(snout)The crankshaft snout extends through the front end of the engine block. The camshaft timing assembly is directly connected to the snout, as are engine-driven accessories. • Flange:The crankshaft flange is the mounting structure for the engine's flywheel.

29. Flywheel • is simply a heavy wheel, usually composed of metal. from disk to saucer, and is typically symmetric. • flywheel used for Energy store: • Store energy from power stroke and use it to make the other strokes  Stability • It has big mass and make stability for engine

30. Cam Shaft Cam shaft used for • operating the valves. The camshaft can be either be located overhead or at the side of the engine • It get its motion from crank shaft through system of gears

31. FORCES ON CRANKSHAFT • The product of combustion chamber pressure That level of force exerted onto a crankshaft rod journal produces substantial bending and tensional moments and the resulting tensile, compressive and shear stresses. • Piston Acceleration is another major source of forces imposed on a crankshaft. The combined weight of the piston, ring package, wristpin, retainers, the conrod small end and a small amount of oil are being continuously accelerated from rest to very high velocity and back to rest twice each crankshaft revolution.

32. CRANK SHAFT MATERIAL • The steel alloys typically used in high strength crankshafts have been • PROPERTIES OF CRANK SHAFT ALLOY • Surface and core hardness • Ultimate tensile strength, • Yield strength, endurance limit (fatigue strength), • impact resistance, corrosion resistance

34. Forging and casting • Crankshafts can be forged from a steel bar usually through roll forging or cast in ductile steel. Today more and more manufacturers tend to favor the use of forged crankshafts due to their lighter weigh. • Machining • Crankshafts can also be machined out of a billet, often using a bar of high quality vacuum remelted steel. Even though the fiber flow

35. HEAT TRATMENT • Heating the part in an oven until the temperature throughout the part (1550°F to 1650°F ) • the part is removed and rapidly cooled ("quenched”). (high-strength, high-hardness- lacks sufficient ductility and impact resistance) • the part is placed in a ‘tempering’ oven and soaked for a specific amount of time at a specific temperature (double-tempering) • Nitriding is the process of diffusing elemental nitrogen into the surface of a steel, producing iron nitrides (FeNx). The result is a hard, high strength case along with residual surface compressive.

38. Classification of internal combustion engine • According to No of stroke: 2-stroke engine 4-stroke engine System of cooling Water cooling Air cooling System of ignition Spark ignition engine Compression ignition engine Fuel Gasoline engine Diesel engine Alcohol engine Natural gas

39. Piston Arrangement • Straight engine(inline) • Usually found in four- and six-cylinder configurations, the straight engine, or inline engine is an internal-combustion engine with all cylinders aligned in one row, with no offset. They have been used in automobiles

40. Flat Engine • A flat engine is an internal combustion engine with multiple pistons that all move in the horizontal plane. The most popular and significant layout has cylinders arranged in two banks on either side of a single crankshaft

41. V engine • is a common configuration for an internal combustion engine. The cylinders and pistons are aligned, in two separate planes or 'banks', so that they appear to be in a "V" when viewed along the axis of the crankshaft. The Vee configuration generally reduces the overall engine length, height and weight compared to an equivalent inline configuration.

42. V and VR ENGINE

43. The W engine • is an engine configuration in which the cylinder banks resemble the letter W in the same way a V engine

44. Rotary Engine • The rotary engine was an early type of internal-combustion engine, usually designed with an odd number of cylinders per row in a radial configuration, in which the crankshaft remained stationary and the entire cylinder block rotated around it.

45. U engine • A U engine is a piston engine made up of two separate straight engines (complete with separate crankshafts) joined by gears or chains.

46. X engine • An X engine is a piston engine comprising twinned V-block engines horizontally-opposed to each other. Thus, the cylinders are arranged in four banks, driving a common crankshaft. Viewed head-on, this would appear as an X. X engines were often coupled engines derived from existing powerplants.

47. Wankel engine • The Wankel engine is a type of internal combustion engine which uses a rotary design to convert pressure into a rotating motion instead of using reciprocating pistons. Its four-stroke cycle takes place in a space between the inside of an oval-like epitrochoid-shaped housing and a rotor that is similar in shape to a Reuleaux triangle but with sides that are somewhat flatter. This design delivers smooth high-rpm power from a compact size • The engine was invented by German engineer Felix Wankel