PAPERS
PISTON AND CRANKSHAFT
Prepared to fulfill the English language course assignment
Lecturer :
Harmawan Wardani, S.Pd., M.Pd.
Group 5
Mochamad Royanul Mustofa 203303030
Rydho Putra Pradana 203303032
Mokhammad Afif Revanza 203303034
D-IV AUTOMOTIVE ENGINEERING TECHNOLOGY ENGINEERING DEPARTMENT
MADIUN STATE POLYTECHNIC MADIUN
2023
FOREWORD
Assalamualaikum wr.wb
Thank Godthanks to God Allah SWT who has made all our affairs easier, especially for us to be able to complete the paper entitled "Piston and Crankshaft"
in order to fulfill the assignment for the Gasoline Motor Technology course. We don't forget to give our prayers and greetings to the great prophet Muhammad SAW, whose intercession we await at Yaumul Kiammah, Aamiin.
Hopefully this paper can make things easier for all of us in terms of understanding piston and crankshaft. In this way, we become more familiar with the parts and functions of the components in the engine. With this paper, it is also hoped that it will help not only in the world of education at the State Polytechnic of Madiun, but it can also be useful for the surrounding community.
We would also like to express our thanks to all parties who have contributed to the success of this paper so that it can be completed on time. We really welcome constructive criticism and suggestions from all of you and your friends for the future to make us even better in making papers with other titles.
We apologize if there are any errors or mistakes in writing this paper. because perfection belongs only to Allah SWT.
Wassalamualaikum wr. wb
Drafting team
Group 5
1 CHAPTER I INTRODUCTION
In the realm of internal combustion engines, the dynamic partnership between the piston and crankshaft forms the core of a mechanical symphony that powers vehicles and machinery across the globe. These two components work in tandem, seamlessly transforming the energy released during combustion into the mechanical force that propels our modes of transportation and drives industrial processes.
A. Piston
A piston is a disc that reciprocates (up and down) inside the cylinder. At the time of the combustion process of the engine, the energy that comes out of the expanding process, transfers that energy into mechanical energy. The piston moves either due to the fuel-air mixture inside the cylinder that has been combusted, or the piston moves due to the fuel-air mixture being compressed.
B. Crankshaft
It is a shaft which transmits the power developed by the engine to the various parts of the vehicle. Without crankshaft your vehicle won't even move an inch though your engine will be running. Crank shaft is the main part of the engine through which the power developed in the engine cylinder is transmitted to the flywheel.
Crankshaft is a shaft which is connected perpendicularly to piston through connecting rod. At the one end of crankshaft, the flywheel is connected. Flywheel is a energy reservoir, that receives energy from the piston during power stroke and it gives back the same energy to the piston during remaining strokes due to the moment of inertia.
CHAPTER II
DISCUSSION
2.1. Piston
a. Definition of Piston
A piston is a cylindrical component that moves reciprocally within a cylinder in an internal combustion engine. Typically sealed within the cylinder and connected to a connecting rod, the piston plays a crucial role in the engine's operation by facilitating the conversion of high-pressure gases generated during the combustion of fuel and air into mechanical motion. The reciprocating motion of the piston is a fundamental part of the engine's four-stroke cycle, contributing to the overall process of converting chemical energy into mechanical energy to propel the vehicle. Pistons are commonly made of durable materials such as aluminum or alloys and are equipped with piston rings to create a seal against the cylinder walls, preventing gas leakage and ensuring efficient engine performance.
b. Function of Piston
The main function or work of the piston is to transfer energy by receiving the impulse that is being generated from the gas inside the cylinder and transfer the energy from the connecting rod to the crankshaft.
Another function is due to the combustion of the mixture of gas which is generating the heat, the piston works to dissipate that heat in the engine cylinder valve.
3 c. Piston Components or Parts
Following are the main parts of piston : 1. Piston Rings.
Piston rings are a very important component. The combustion gas that is released at the time of the engine’s combustion process should not bypass the piston and the friction is the least we can use the ring around the piston.
The rings are provided by sealing between the piston and the cylinder valve. There are two types of piston rings : Compressor Ring and Oil Controller Ring.
2. Piston Head or Crown.
The piston crown is above the piston, due to its location, the piston crown in counter very high pressure and temperature. The piston crown that is used in the timing of the confinement process, the pigment which escapes from the gas exhaust, helps it out of the engine.
3. Piston Ring Grooves.
It consists of grooves above the piston, which employs rings.
4. Piston Skirt.
The piston skirt is the cylindrical valve of the piston. Piston skirts are made slightly rough at the time of manufacturing So that it can retain lubrication and also resist thrust.
5. Piston Pin.
It is also called a gudgeon pin. The pin is used to connect the piston and connecting rod. Harder steel is used as a material.
6. Connecting rod Shaft.
The connecting rod connects the piston to the crankshaft, and this is functions as a liver arm and transfers motion from the piston to the crankshaft.
7. Connecting Rod Bolts.
The bolt is used to connect the clamp and connecting road.
8. Bearings.
The bearing is installed in two parts and together they form a complete circle. Bearing is installed between the connecting rod and the crank pin.
9. Connecting Rod Cap.
The cap is the lower part of the piston assembly. The cap is the lower half of the connecting rod which forms the house for bearing the connecting rod.
d. Piston Working System
The working system of a piston in an internal combustion engine is integral to the engine's operation. The piston undergoes a series of movements within the engine cylinder, contributing to the four-stroke cycle that converts fuel and air into mechanical energy. This sequence of events, known as the four-stroke cycle (intake, compression, power, exhaust), is repeated continuously as long as the engine is running. The reciprocating motion of the piston is converted into rotary motion by the crankshaft through the connecting rod. The rotational motion is then transmitted to the transmission system and ultimately to the wheels of the vehicle.
Piston rings are crucial components that surround the piston and help create a seal against the cylinder walls. This seal is essential for preventing the escape of combustion gases. In summary, the piston's working system involves precise movements within the cylinder that facilitate the intake, compression, power generation, and exhaust of the air-fuel mixture, ultimately transforming chemical energy into mechanical energy to power the vehicle.
5 2.2. Crankshaft
a. Definition of Crankshaft.
Crankshaft is a part of the engine that helps you convert the linear motion of the Piston into rotary motion that can be delivered to the gearbox/wheels.
Without the crankshaft you can't transfer the reciprocating motion of pistons to the drive shaft. It's also the connecting link between the engine and the gearbox/drive shaft. Power is delivered from the crankshaft to the wheels/gearbox.
b. Function of Crankshaft.
The main function of crank shaft is conversion of reciprocating motion into rotary motion. The piston reciprocates due to heat developed inside the engine, this motion is turned into rotary by crank shaft, it transmit the power developed in the engine that is indicated power to the flywheel, the flywheel serves as a energy reservoir. The primary function of a crankshaft is to transfer motion from the piston by means of connecting rod to the transmission system.
It basically converts the reciprocating motion of the piston into rotary motion with the aid of connecting rod which connects a piston to crank shaft.
c. Crankshaft Components or Parts.
Following are the main parts of crankshaft : 1. Crank Pin
The crankpin is a mechanical part of an engine. Which allows the connecting rod to be attached to the crankshaft very firmly. The surface of the crankpin is cylindrical, to give the rotative force to the large end of the connecting rod. There are also known as connecting rod journals.
2. Main Journals
They have fastened to the engine block and its appearance is round in shape. These bearings hold the crankshaft in position and provide it to rotate inside the engine block. This bearing is such as a plain bearing or journal bearings. The main bearings as per the engine vary between engines, often according to the forces given by the engine.
3. Crank Web
Crank web is a most essential part of the crankshaft. Which connects the crankshaft to the main bearing journals very accurately.
4. Counterweights
The counterweights are a type of weight, that applies opposite force, which provides balance and stability to the crankshaft and these are mounted on the crank web. The reason for installing counterweights in the crankshaft is, they can eliminate the reaction caused by rotation. And it is very helpful for achieving the higher RPM and makes the engine run easily.
5. Thrust Washers
At some points, two or more thrust washers are attached to stop the crankshaft from moving lengthways. These thrust washers assemble among the machined surfaces in the web and the crankshaft saddle. To maintain a small gap and reducing the amount of lateral movement possible for the crankshaft. In many engines, these are made as part of the main bearings, usually, older types, use separate washers.
6. Oil Seals
On both ends of the crankshaft, there are some ways to prevent the oil escaping from these openings should be provided. An oil seal is a poor
7
part. But it needs a lot of labor to eliminate the transmission, clutch, flywheel, and crankshaft to access it. It is therefore suggested that the oil seal be replaced whenever the engine is ruined and parts are accessible.
7. Flywheel Mounting Flange
In most cases, the crankshaft attaches to the flywheel through the flanges.
The diameter of the crankshaft wheel end is larger than the other end.
This gives a flange face to mount the flywheel.
d. Crankshaft Working System.
Convert the reciprocating motion of piston & connecting rod into rotary motion. This rotary motion then supplies to flywheel & then drive shaft. The piston moves up and down in the cylinder due to fuel combustion. This is called reciprocating motion. Now this motion must be converted to rotary motion so that a suitable output can be obtained.
In engines used in cars the reciprocating motion of pistons is converted to rotational motion by the crankshaft which eventually rotates the wheel.
Crankshaft converts reciprocating motion to rotational motion. It is how you get your vehicle to move.
Due to combustion of fuel in the cylinder, energy is generated and due to this the piston moves downwards during the power stroke. This reciprocating motion of the piston is converted to rotary motion of the crank. With this crank, crankshaft also rotates. This crankshaft is then connected to the gearbox of a vehicle. Thus it is responsible for transmission of power.
CHAPTER III CLOSING Conclusing
The conclusion in this paper is that the :
a) The piston of a car is a vital component that plays a significant role in the engine’s functioning and the component that carries out the suction and exhaust strokes. The main function or work of the piston is to transfer energy by receiving the impulse that is being generated from the gas inside the cylinder and transfer the energy from the connecting rod to the crankshaft.
b) A balanced crankshaft can provide you a smooth-running, more power, less waste of energy, and reduces the vibrations of the engine. It is mainly employed to convert the linear motion to the rotational motion.
