what is a crank shaft and how does it work

what is a crank shaft and how does it work

What is Crankshaft and How Doеs It Work A crankshaft is a rotating shaft that is driven by a crank mechanism. what is a crank shaft and how does it work It is a mechanical unit that helps convert the linear motion of the piston into rotational motion. The crankshaft is an important part of the engine’s power transmission system. Located inside the engine crankshaft block, what is a crank shaft and how does it work it works by using a connecting rod to convert the reciprocating motion of the piston into rotational motion. This rotating motion created by the crankshaft drives the flywheel, which in turn turns the wheels of the vehicle. what is a crank shaft and how does it work Now that wе’vе еxaminеd thе componеnts lеt’s еxplorе how a crankshaft works within thе contеxt of an intеrnal combustion еnginе: 1. Powеr Strokе Initiation: – Thе procеss bеgins during thе powеr strokе of thе еnginе cyclе. what is a crank shaft and how does it work In this strokе, thе comprеssеd fuеl-air mixturе is ignitеd by thе spark plug (in gasolinе еnginеs) or by thе hеat gеnеratеd during comprеssion (in diеsеl еnginеs). – Thе rapid еxpansion of thе hot gasеs from combustion еxеrts a forcе on thе piston, driving it to movе downward within thе cylindеr. This downward motion gеnеratеs thе mеchanical powеr within thе еnginе. 2. Piston Motion: – As thе piston movеs downward, it is connеctеd to thе connеcting rod via thе piston pin. This connеction еnablеs thе piston to transfеr its linеar motion to thе connеcting rod. – Thе connеcting rod, in turn, is attachеd to thе crankshaft at thе crank pin. what is a crank shaft and how does it work As thе piston movеs, it pivots thе connеcting rod, causing thе crankshaft to rotatе about its axis. 3. Crankshaft Rotation: – As thе crankshaft rotatеs, thе rotational motion is transmittеd to thе transmission and ultimatеly to thе whееls of thе vеhiclе. This rotation of thе crankshaft gеnеratеs thе mеchanical powеr that propеls thе vеhiclе forward. 4. Rеvеrsing thе Procеss: – Oncе thе powеr strokе is complеtеd, thе еnginе progrеssеs through thе othеr phasеs of thе four-strokе cyclе, including еxhaust, intakе, and comprеssion strokеs. what is a crank shaft and how does it work During thеsе strokеs, thе crankshaft rеvеrsеs its rotation, guiding thе piston back up thе cylindеr. – This еntirе procеss rеpеats hundrеds or thousands of timеs pеr minutе, dеpеnding on thе еnginе’s RPM (rеvolutions pеr minutе), to providе continuous powеr and propulsion. Significancе of Crankshafts The internal combustion (IC) engine has been an important prime mover in our society since its invention in the last quarter of the 19th century [for more information, see, for example, Haywood (1988)]. Its purpose is to generate mechanical energy from the chemical energy contained in the fuel and released by the combustion of the fuel inside the engine. what is a crank shaft and how does it work It is this unique feature, that the fuel is burned inside the work-producing part of the engine, that gives IC engines their name and distinguishes them from other types such as external combustion engines. what is a crank shaft and how does it work Although gas turbines meet the definition of an IC engine, the term is traditionally associated with spark-ignition (sometimes called otto, gasoline, or gasoline engines) and diesel engines (or compression-ignition engines). Internal combustion engines are used in marine propulsion and power generation packages ranging from more than 100 MW capacity to less than 100 W portable devices. This means that the size and characteristics of today’s engines vary widely between large diesels. 1,000 mm and reciprocating at speeds as low as 100 rpm for small gasoline two-stroke engines with cylinder bores greater than about 20 mm. Within these two extremes are medium speed diesel engines, heavy vehicle diesels, truck and passenger car engines, aircraft engines, motorcycle engines and small industrial engines. what is a crank shaft and how does it work Among all these categories, passenger car petrol and diesel engines dominate as they are the largest production engines in the world; Therefore, their impact on social and economic life is very important. Most reciprocating internal combustion engines have what is known as a four-stroke cycle (Figure 1), which is divided into four processes: intake, compression, expansion/power, and exhaust. what is a crank shaft and how does it work Each engine cylinder has four strokes of its piston to complete the power-generating sequence corresponding to two crankshaft revolutions. Typеs of Crankshafts Crank Types  There can  three types of cranks which are listed and described below- 1. Overhung crank 2. Disc crank 3. Center crank or side crank 1. Overhung crank- An overhung crank has two ends, one end of which can  fixed to the shaft by means of a key, and the other end hangs like a cantilever, hence it can called an overhung crank. It can made of forged steel. The crank pin can mounted to the crank arm with a rivet or press fit or shrink fit. Overhung cranks can generally used in medium and large horizontal machines. 2. Disc Crank- Its shape can disc-like. A crank pin can placed at some distance from the center of the disc. It works like an overhung crank. The disk can made thicker where the crank pin can mounted and the rest of the disk can made thinner to balance the weight of the crank pin and connecting rod, the larger end of which fits over the crank pin. Disc cranks can mostly used for high speed and medium speed engines. 3. Center or side crank- A center crank has crank arms on either side of the crank pin. That’s why called a center crank. The crank arms can connected to the crankshaft supported by bearings. Center cranks can used in multi-cylinder engines where two or more cylinders produce power on a single crankshaft. Crankshaft Manufacturing Procеss The crank can usually made of … Read more

working principle of 2 stroke ic engine

working principle of 2 stroke ic engine

working principle of 2 stroke ic engine A two-stroke engine is one that completes its operating cycle in one revolution of the crankshaft or two strokes of the piston. working principle of 2 stroke ic engine In this engine the operations of the intake and exhaust processes of the four-stroke engine are taken care of by the incoming fresh charge, which is compressed in the crankcase or by a separate blower, near the bottom dead center of the engine piston. will happen. , the engine piston only needs to compress the new charge and expand the combustion products. Since a two-stroke engine has twice the number of revolutions per minute as a four-stroke engine operating at the same speed and with the same number of cylinders, it theoretically produces twice the power while operating at the same average effective pressure. working principle of 2 stroke ic engine Like a four-stroke engine, the power output of this engine depends on the number of air per minute available for combustion.   Many two-stroke engines have greatly simplified engine construction, using the piston as a slide valve, with intake and exhaust ports cut into the side of the cylinder. If the engine runs on the Otto cycle, the charge consists of a proper mixture of fuel and air, whereas the charge for a diesel or dual combustion cycle consists of pure air. working principle of 2 stroke ic engine There are several difficulties in applying the two-stroke principle to small high-speed CI engines, although these are by no means insurmountable. For SI engines, the two-stroke cycle principle is used for a large number of engines, working principle of 2 stroke ic engine from small single-cylinder model engines producing a fraction of a kilowatt to the largest aircraft engines capable of 2500 kW or more units. Types of two-stroke engines There are basically two types of two-stroke engines depending on the scavenging method used: The details of the above two types of two-stroke engines are briefly discussed in the following sections. Crankcase scavenged engine One of the simplest types of two-stroke engines. working principle of 2 stroke ic engine In this engine, the charge (fuel-air mixture in SI engines and air in CI engines) is compressed in the crankcase below the piston during the expansion stroke. This engine has three ports. IC machine (i) Crankcase swept engine (ii) Separately designed machine (i) Intake port in crankcase (ii) Port of transfer (iii) Port of exit Crankcase-scavenged two-stroke engine The compressed charge forces the combustion products into the engine cylinder through the charge transfer port. This process is called scavenging, and engines of this type are called crankcase-scavenged engines. As the piston moves down, it first opens the exhaust ports, and the cylinder pressure drops to atmospheric levels as the combustion products exit these ports. working principle of 2 stroke ic engine In addition, the downward movement of the piston exposes the transfer ports, which allow the slightly compressed mixture in the crankcase or air (depending on the type of engine) to enter the engine cylinder. The top and ports of the piston are usually designed so that fresh air is directed toward the top of the cylinder before flowing toward the exhaust ports. It is intended to clear the top of the cylinder of combustion products and reduce the flow of fresh fuel-air mixture directly through the exhaust ports. The projection on the piston is called a deflector. As the piston returns from the bottom center, the transfer ports and exhaust ports are closed and charge compression begins. working principle of 2 stroke ic engine The movement of the piston during compression reduces the pressure in the crankcase so that fresh mixture or air can be drawn into the crankcase through the inlet reed valve. Ignition and expansion occur normally, and the cycle repeats itself. The engine is undercharged by one cylinder displacement volume due to flow restrictions at the inlet reed valve and transfer port. Optional machine Another type of engine that uses an external device such as a blower to clean the combustion products is called an externally or separately scavenged engine. Details of this type of machine . In these engines the air-fuel mixture is supplied to the inlet manifold at a slightly higher pressure. working principle of 2 stroke ic engine As the piston moves downward along the expansion side, it opens the exhaust ports approximately 60◦ before the bottom center. After about 10◦, when the pressure in the cylinder is low enough, the inlet ports are opened and the cleaning process takes place. The inlet port is designed so that most of the air flows through the top of the cylinder, moves down the exhaust side, and forms an annulus before reaching. working principle of 2 stroke ic engine This ensures cleanliness of the upper cylinder block. Piston deflectors are not used because they are heavy and overheat at high outputs. Compared to normal crankcase scavenged engines with deflector pistons, the scavenging process is more efficient in this type of engines. Opposite of piston or end-to-end scavenged engine: Another type of two-stroke engine is called the opposed piston type or sometimes called the end-to-end scavenged engine. Details of this type of machine. In this way the discharge ports are opened first. The inlet port is designed so that the air or mixture enters tangentially, giving a reciprocating motion. working principle of 2 stroke ic engine Vortex helps prevent mixing of new charge and combustion products during the cleaning process. At the beginning of the compression stroke, the exhaust ports close first. As the flow passes through the inlet ports the cylinder pressure begins to increase and the inlet ports close when the pressure is close to the inlet manifold pressure. Note that in this opposed piston engine the two pistons are slightly out of phase. working principle of 2 stroke ic engine In loop-scavenged engines the port timing is symmetrical so that the exhaust port closes after the inlet … Read more

What is open and cross belt mechanism

What is open and cross belt mechanism

Open the belt drive and cross belt drive Mechanical power transmission systems are used to transmit mechanical power What is open and cross belt mechanism (in the form of rotational torque) from a drive shaft (such as a prime mover) to a driven shaft (such as an engine unit). A belt drive is a mechanical drive (gear drive, chain drive, and rope drive among others) that is used to transmit motion, torque, and power from one shaft to another. Initially, a pulley of required diameter is applied rigidly to the shaft. An endless belt wraps around the nadis, maintaining proper tension to avoid slipping. What is open and cross belt mechanism The belt, partially wrapped around it, passes over the pulley and acts as a flexible intermediate link between the drive and the driven shaft. The frictional force between the belt and the pulley helps transmit motion and power from one shaft to the other. The initial tension applied to the belt, as well as the friction characteristic between the mating surfaces, determine the power transfer efficiency. What is open and cross belt mechanism For a constant speed on the driven shaft, the pulley diameter determines the speed ratio and rotational speed of the driving shaft. A flexible belt helps in reducing vibration, thereby preventing displacement of the driving element. Although it cannot provide constant speed ratio due to inherent drift, it is very useful for short and long distance power transmission. What is open and cross belt mechanism However, slip prime movers can be prevented from overloading. The direction of rotation can be changed using open or crossed belt drives, while the ratio of speed and rotational speed is maintained by the diameter of the pulleys for the drive and driven shafts. This affects the power transfer efficiency due to changes in the wrap angle between the belt and the pulley. This classification mostly applies to flat belts because V-belts are almost always used in an open configuration. An arrangement in which an endless (joint) belt passes from one pulley to another without crossing it is called an open belt drive. Here the driven shaft rotates in the same direction as the drive shaft. Also, the wrap angle is always below 180°; Due to this, the power transfer efficiency also decreases. On the other hand, in cross belt drive, the belt runs from above one pulley to below the other pulley, thus crossing itself. What is open and cross belt mechanism Right here the driven shaft rotates within the opposite direction. The wrap angle also increases, resulting in higher energy transfer efficiency. However, constant rubbing of the belt shortens the life of the belt and causes the belt to wear out quickly. Also, it requires a relatively long belt. Table of Differences Between Open Belt Drive and Cross Belt Drive Open belt drive In an open belt drive, the belt moves from one pulley over the other without crossing. Here the entire belt is in the same plane in each rotation. Here the drive and driven shafts rotate in the same direction. The wrap angle or contact angle between belt and pulley is always less than 180°. Due to small wrap angle, power transfer efficiency is low. In open belt system the length of belt is relatively short. Here the belt does not touch itself. So no rubbing. Thus the belt exhibits long life. Belt vibrates (whips) if center distance between two pulleys is too large. Cross belt drive In cross belt drive, the belt moves from one pulley above to another below, What is open and cross belt mechanism thus crossing itself. Here the belt changes in two different planes in each revolution. Here the drive and driven shafts rotate in opposite directions. Wrap angle is always greater than 180°. Power transmission efficiency is also high due to large wrap angle. For the equal pulley length and middle distance, a pass belt drive calls for an extended belt. As it passes between the two pulleys, the belt rubs against each other and gradually wears out. Crossbelt system is free from such vibrations.   Belt configuration of cross belt drive The shape of the flexible element in the belt drive may vary. What is open and cross belt mechanism A flat belt is a composite belt with a rectangular cross-section where the width is greater than the thickness (height). A V-belt is an endless belt with a trapezoidal cross-section of equal width and height. A ribbed belt is similar to a flat belt, but has teeth along the inner circumference that mesh with corresponding slots on the pulley. Open and crossed belt configurations are associated with flat belts only. In an open belt system, What is open and cross belt mechanism the belt passes over one pulley without crossing over the other. In a closed belt system, the belt runs from above one pulley to below the other, thus crossing itself. Belt Buckle In an open belt configuration, the inside of the belt touches the pulley; However, the belt does not bend or flip as it travels from one pulley to another. So the belt stays in the same plane throughout the cycle. In a cross belt drive, the belt runs from one pulley up to the other pulley down. Since only an inner portion of the belt can wrap around or touch the pulley, the belt must can bent 180° between the driver and the driven shaft. There are two such turns for each revolution of the belt. Direction of rotation An important advantage of belt drives over gear drives is the ability to rotate the drive and driven shaft in the same or opposite direction without the use of other accessories. In single phase, the gear drive only rotates in the opposite direction unless the intermediate or idle gear can engaged. What is open and cross belt mechanism An open belt drive can rotate the driven shaft in the same direction as the drive shaft; Whereas, … Read more