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What are the 5 kinds of lubrication systems and state clearly their application and how they function?
SPLASH The splash system is no longer used in automotive engines. It is widely used in small four-cycle engines for lawn mowers, outboard marine operation, and so on. In the splash lubricating system, oil is splashed up from the oil pan or oil trays in the lower part of the crankcase. The oil is thrown upward as droplets or fine mist and provides adequate lubrication to valve mechanisms, piston pins, cylinder walls, and piston rings. In the engine, dippers on the connecting-rod bearing caps enter the oil pan with each crankshaft revolution to produce the oil splash. A passage is drilled in each connecting rod from the dipper to the bearing to ensure lubrication. This system is too uncertain for automotive applications. One reason is that the level of oil in the crankcase will vary greatly the amount of lubrication received by the engine. A high level results in excess lubrication and oil consumption and a slightly low level results in inadequate lubrication and failure of the engine. A splash lubrication system is provided for motor vehicle transmissions and comprises an oil sump in the bottom portion of a case. The case accommodates a transmission shaft provided with gears which are immersed in the oil at least partly when the said oil sump is filled completely. In order to prevent the synchronizing mechanism from being blocked by cold and, consequently, very viscous oil in the presence of extremely low operating conditions--a condition which could lead to unsynchronized faulty gear shifting operations and, thus, damage to the transmission, the oil sump is connected with a cavity into which oil is drawn from the oil sump under low operating temperature conditions of the transmission. To this end, preferably, an expansion body is arranged in a cavity in the transmission shaft which contracts under cold conditions, and the cavity is connected. Combination Splash and Force Feed In a combination splash and force feed (fig.), oil is delivered to some parts by means of splashing and other parts through oil passages under pressure from the oil pump. The oil from the pump enters the oil galleries. From the oil galleries, it flows to the main bearings and camshaft bearings. The main bearings have oil-feed holes or grooves that feed oil into drilled passages in the crankshaft. The oil flows through these passages to the connecting rod bearings. From there, on some engines, it flows through holes drilled in the connecting rods to the piston-pin bearings. Cylinder walls are lubricated by splashing oil thrown off from the connecting-rod bearings. Some engines use small troughs under each connecting rod that are kept full by small nozzles which deliver oil under pressure from the oil pump. These oil nozzles deliver an increasingly heavy stream as speed increases. At very high speeds these oil streams are powerful enough to strike the dippers directly. This causes a much heavier splash so that adequate lubrication of the pistons and the connecting-rod bearings is provided at higher speeds. If a combination system is used on an overhead valve engine, the upper valve train is lubricated by pressure from the pump. FORCE FEED A somewhat more complete pressurization of lubrication is achieved in the force-feed lubrication system (fig.). Oil is forced by the oil pump from the crankcase to the main bearings and the camshaft bearings. Unlike the combination system the connecting-rod bearings are also fed oil under pressure from the pump. Oil passages are drilled in the crankshaft to lead oil to the connecting-rod bearings. The passages deliver oil from the main bearing journals to the rod bearing journals. In some engines, these opening are holes that line up once for every crankshaft revolution. In other engines, there are annular grooves in the main bearings through which oil can feed constantly into the hole in the crankshaft. The pressurized oil that lubricates the connecting- rod bearings goes on to lubricate the pistons and walls by squirting out through strategically drilled holes. This lubrication system is used in virtually all engines that are equipped with semi floating piston pins. Full Force Feed In a full force-feed lubrication system (fig.), the main bearings, rod bearings, camshaft bearings, and the complete valve mechanism are lubricated by oil under pressure. In addition, the full force-feed lubrication system provides lubrication under pressure to the pistons and the piston pins. This is accomplished by holes drilled the length of the connecting rod, creating an oil passage from the connecting rod bearing to the piston pin bearing. This passage not only feeds the piston pin bearings but also provides lubrication for the pistons and cylinder walls. This system is used in virtually all engines that are equipped with full-floating piston pins. kinds of Lubrication Differing widely in viscosity, specific gravity, vapor pressure, boiling point, and other properties, lubricants also offer a wide range of selection for the increasingly varied needs of modern industry. But whatever their derivation or properties, the purpose of lubricants is to replace dry friction with either thin-film or fluid-film friction, depending on the load, speed, or intermittent action of the moving parts. Thin-film lubrication, in which there is some contact between the moving parts, usually is specified where heavy loads are a factor. In fluid, or thick-film, lubrication a pressure film is formed between moving surfaces and keeps them completely apart. This type of lubrication cannot easily be maintained in high-speed machinery and therefore is used where reciprocating or oscillating conditions are moderate.
What is mean by hot working and cold working?
When ur hot and ur working then it is hot working, if ur cold and ur working then it is cold working
Why does cold rolling decreases hardness?
Cold rolling involves application of load due to this the grains are elongated...so the material is work hardened and causes to rise internal stresses in the material...due to these stress cold rolling decreases hardness....so after cold rolling a heat treatment process is preferred...
What would happen to the physical properties of a cold worked material if it were fully annealed and cold worked further?
It would have approximately the same characteristics of the material before it was annealed. In other words, it would almost be the same as the first time it was cold worked, assuming nothing was done to the material before it was cold worked the first time.
What is cold rolling of steam turbine?
When Turbine shaft temp is below 100 deg.centigrade,Then rolling of turbine carried out it is called cold rolling.
What is the fuel used in aircraft?
Most large aircraft that have turbine-powerd engines use a fuel called Jet A. Jet A is basically highly refined kerosene. Jet A is used in the United States, Jet A-1 is used in the rest of the world. Where extreme cold conditions exist, Jet B is used for its better cold weather performance. Other aircraft that have reciprocating (piston) engines use Aviation gasoline, which is similar to what is used in automobiles.
What were the design problems with early steam engines?
The early steam engines were atmospheric: they used steam pressure to raise a piston in a cylinder and then by condensing the steam used air pressure to push the piston back down to repeat the cycle. To condense the steam cold water was injected into the cylinder; not only did this condense the steam but it also cooled the cylinder down. When steam was re-introduced energy was taken from the steam in reheating the cylinder; this resulted in a large amount of wasted energy which translated into the engine requiring lots of fuel. This was improved by using a separate condenser so that the cylinder was kept hot and the separate condenser was kept cold, resulting in a dramatic reduction in the amount of fuel needed. Also the seals on the cylinder were not perfect so that steam was lost and air leaked in during the cycle (again reducing its efficiency). With the improvement in cylinder seals and high pressure boilers, later steam engines were able to push the piston in both directions, delivering constant power on both halves of the cycle.
Why traces of smokes when aircraft fly in high altitude?
That is condensation from hot engines in cold air.
What is a stirling engine?
The Stirling engine was invented by Reverend Dr. Robert Stirling and patented by him in 1816.It is an engine that gets it's power from the movement of heat energy from a hot place to a cold place. It consists of two cylinders, the first one is called the displacement cylinder and the second one is the power cylinder.The displacement cylinder has two sections, a hot section and a cold section, the piston in the displacement cylinder is a loose fit so that air or gas can pass by when it is moving, the purpose of this piston is to move the air or gas from the hot section to the cold section and back to the hot section hence "displacing it".Second is the power cylinder containing a double acting piston that is connected to a crankshaft fitted with a fly wheel.When the displacing piston moves to the cold part of the cylinder, the largest volume of air or gas is in the hot part of the displacement cylinder, where it will heat up and expand to a higher volume and push the power piston outwards, when the displacement piston moves to the hot side of the cylinder the air or gas moves over to the cold side of the cylinder, where it will cool down and shrink to a smaller volume and form a vacuum that sucks the power piston in the opposite direction.
Why is a diesel engine running rough when its cold?
Diesel engines, unlike gas engines do not have any spark plugs. The reason that they do not need a spark plug is because in diesel engines, the air is compressed much, much more than in a gas engine. The more that you compress the air, the more that the air is heated. Diesel engines have so much compression that the air inside of your cylinder becomes super heated and there is no need for a spark plug. The air is so hot that when the diesel fuel is injected into the cylinder, the diesel fuel ignites and the piston is pushed down via the "explosion" that takes place when the piston reaches tdc(top dead center). Because of this, diesel engines need to warm up. This is why diesel engines have glow plugs. The glow plugs warm the block and help the engine to heat up faster.
Meaning of cam ground of piston?
Aluminum expands much more than Cast Iron, so when the piston to cylinder wal clearance is measured at room temperature there must an allowance to allow for expansion when the piston heats up. The amount of clearance depends upon the design of the engine and the anticipated operating temperature. Air-cooled engines run very hot so they require more clearance than water-cooled engines. On a Cushman piston the reference point for more clearance than water-cooled engines. On a Cushman piston the reference point for clearance measurements is at the top of the skirt perpendicular to the piston pin All areas of the piston do not expand the same; the top of the piston runs the hottest so it expands the most. The skirt runs the coolest so it expands the least. For this reason the diameter at top of the piston will normally be smaller, and the diameter at the bottom of the skirt will normally be a little larger, than the diameter at the top of the skirt. Also, the piston does not expand the same all the way around its circumference. The diameter measured across the piston pin will expand more than the diameter-measured perpendicular to the piston pin. Therefore, the piston is "cam ground", or made slightly oval, with the smaller diameter measured across the piston pin. When the piston heats up to operating temperature it will then be round. If the piston were not cam ground, the to operating temperature it will then be round. If the piston were not cam ground, the piston to cylinder wall clearance would have to be extremely high when the engine was cold to allow for expansion, and it would not be round when at operating temperature. This could cause piston slap and other problems. piston to cylinder wall clearance would have to be extremely high when the engine was cold piston to cylinder wall clearance would have to be extremely high when the engine was cold to allow for expansion, and it would not be round when at operating temperature. This could cause piston slap and other problems Cushman engines are usually set to a clearance of about .006 inch measured at the reference point described in paragraph one. The clearance at operating temperature will be much less, and if sufficient allowance is not made for expansion, the piston will expand to much less, and if sufficient allowance is not made for expansion, the piston will expand to the diameter the cylinder wall and freeze up. During break-in everything is running extra the diameter the cylinder wall and freeze up. hot due to the increased friction, and the piston temperatures get very high. If the engine is run at high speeds during this period it will almost always freeze up and may damage the run at high speeds during this period it will almost always freeze up and may damage the engine The following measurements are from a Cushman NOS +.030 cam ground piston Top of skirt perpendicular to the piston pin 3.024 (.006 clearance) Top of skirt measured across piston pin 3.011 Bottom of skirt perpendicular to pin 3.025 Bottom of skirt parallel to piston pin 3.012 Top of Piston and ring lands 3.005 In this case the clearance to a nominal 3.000 inch cylinder bore is .006 inch, the elliptica amount is .013, the skirt is .001 larger at the bottom than at the top, and the top of the piston is .019 less than the widest point on the skirt. These measurements are for llustration only and individual pistons may vary considerably
What is the working principle of diesel engine?
Diesel engines work much in the same way as any other internal combustion engine. They require the same 4 things to run; fuel, air, ignition, and compression. The main difference is that a diesel engine does not have sparkplugs, which are used in gasoline engines to ignite the fuel. Diesel engines instead use high cylinder compression to press the mixture of fuel and air into as small of an area as possible. This compression causes heat in the cylinder, which causes the fuel to ignite and push the piston back down, causing the crankshaft to rotate, which power's vehicle's motion. Some diesel engines use "Glow Plugs", to pre-heat the cylinder head, which help the engine start when cold.
What is working principle of diesel engine?
Diesel engines work much in the same way as any other internal combustion engine. They require the same 4 things to run; fuel, air, ignition, and compression. The main difference is that a diesel engine does not have sparkplugs, which are used in gasoline engines to ignite the fuel. Diesel engines instead use high cylinder compression to press the mixture of fuel and air into as small of an area as possible. This compression causes heat in the cylinder, which causes the fuel to ignite and push the piston back down, causing the crankshaft to rotate, which power's vehicle's motion. Some diesel engines use "Glow Plugs", to pre-heat the cylinder head, which help the engine start when cold.
What are the impacts of Cold War?
Today's hi-tech aircraft are the result of cold war experience and research, which in turn were combat tested in the Korean & Vietnam Wars. Nuclear engines. Landing a man on the moon; the space race.
Why do fighter jets have vapour trails?
All aircraft engines emit hot air and they are usually flying in very cold air, so the hot air appears as a vapour trail.
What causes cold engine knock on a 1997 Chevrolet Lumina 3.1?
Cold engine knock that goes away after warmup is usually piston slap. Worn pistons worn cylinder bores, wrong oil (too light) on a high mileage engine.
What is the function of the cold water in Newcomen's steam engine?
The cold water is used to cool down the steam in the cylinder of the engine. A jet of water from the cold-water reservoir enters the cylinder at the end of the up-stroke. This creates a vacuum due to the condensation of the steam. The pressure of the air above the piston now forces it down, raising the pump rods. This allows the engine work on indefinitely.(check the related link for an illustration)
