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  1. 48 likes
    Basically a Pump is used for liquid or fluid to transform it to a much high pressure head while a Compressor is used for gases to transform from low to a much high pressure. From Mechanical Engineering point of view liquid is incompressible so Compressor cannot be used for liquid substances. Posted by AbdulQadir Abba Sheriff on linkedin
  2. 19 likes
    Shaft is a mechanical element that transmit power and torque moment. Usually shafts are the elements with gears and pulleys attach on them (power transmission). The axle on the other hand is a mechanical element that does not transmit power. It can rotate or it can stand still. It is only loaded with bending moments. In vehicles, the terminology is same. The shafts that transmit power to the wheels are called drive shafts. The driven wheels have axles. Some people like to call the drive shafts axles (or half axles), from where the confusion can occur. The right term is drive shafts.
  3. 16 likes
    While both devices provide a form of forced induction for internal combustion engines The primary difference lies in how the devices are powered. Turbochargers are powered by exhaust gasses. Superchargers are powered by a belt, chain link, or gears, directly to the engine (the crankshaft in most cases). Turbochargers perform better at higher rpm's do to more exhaust gases spinning the turbine which then in turn causes the compressor to draw in more air. This has a downside due to lag time which can be referred to as spooling up. Superchargers work better at low RPM's due to the direct link to the engine and lack of lag time however they are limited to rotating at a max speed matching that which the crankshaft can turn the mechanical linkage to the supercharger itself. One system not mentioned in this article is the twin charger system. This combines the benefits of both the supercharger and a turbocharger in creating a zero gap power band. The supercharger takes care of the lower RPMs while the turbo kicks in during the higher rpm's. The applications of this are mostly seen on engines with smaller displacement and a wide rpm range.
  4. 14 likes
    In DTSi, instead of 1 we are using 2 spark plugs. Flame front formed is able to consume more air-fuel mixture as compared with 1 spark plug, thus more complete burning and more efficiency. in DTS-Si, with addition of 2nd spark plug, what they are doing is relocating valves position. With proper designing of inlet and outlet valves you can induce extra swirl for inoming air fuel mixture. Due to turbulence, extra efforts are provided for proper mixing of air and fuel. (We can not allow petrol to go in liquid droplet form, it should be finely atomized). With well atomized air fuel mixture, efficiency increases.
  5. 13 likes
    This is one important point missing in the two previous answers. The "cc rating" of an engine is a volume measure, as previously stated, but it is not the actual cylinder volume. Rather, it is the swept volume of the cylinder, also called the "displacement" of the cylinder. The actual cylinder volume is always somewhat greater than this value because the piston at TDC does not leave zero cylinder volume. The small volume remaining at TDC is called the "clearance volume," the volume available for the early stage of combustion. DrD
  6. 12 likes
    Most of the time gears are used for reduction. So pinion is smaller as compared to gear, i.e. no of teeth on pinion are less as compared to gear. This in accordance affects the number of cycles. Thus in any operation, pinion performs more cylces as compared to gear. More cycles means more wear and hence generally pinion material is selected such that its hardness is more than material of Gear.
  7. 12 likes
    Basic Difference is the how their are measured.. [1] i.e. A pipe is measured by ID(inner diameter) and a tube is measured by OD(outer diameter). [2] a pipe is like a vessel to store a liquid/gas so inside volume is important factor, while a tube is seen as structual member so total volume is important factor.
  8. 9 likes
    ABS- it allows the brakes to be applied while maintaining a tractive contact with the road. it does not allow the wheels to be stopped a once. if it was stopped at once due to inertia(because of the speed with which it comes), the vehicles skids. it is more prominent in low friction surfaces like on ice, wet road etc. In ABS the wheels are not stopped at once. It grips the disc mounted on the wheel. the disc is pressed and released with a gap of nanoseconds. thus the driver do not actually feel it. It increases the braking distance. EBD- It is an electronic device that is mounted on the vehicle, that actually varies the amount of braking force on each wheel depending upon the road conditions. if one wheel is on a high friction surface less braking force is required on that wheel. thus by sensing the road conditions the amount of brake force is varied.
  9. 8 likes
    Washers are used when bolting to make stronger the joint and to reduce bolt fatigue due to inconsistent loads. Any stretch or flattening of parts is likely to be less than the compression of the washer thus, the bolt won't loosen much.
  10. 7 likes
    Tyres are mixture of various rubbers with carbon black added. Carbon black improves traction and wear resistance of pure rubber. Another reason is that black color has higher absorption capability by which the tyre of any vehicle becomes adhesive to road
  11. 6 likes
    Oh god... I guess diesel engines don't use spark plugs because the air/fuel mixture isn't as explosive as is in the case of petrol (or gasoline). Therefore you cannot spark ignite it. That is the reason why diesel engines have a high compression ratio (close to 20 as has been said), which heats up the air being compressed in the cylinder to a high enough temperature. Fuel is then injected straight into the cylinder, where it ignites because of the high temperature of the air and that is it. That's why spark plugs are not needed. The thing is, in petrol engines you used to squirt the fuel into the air intakes, where it mixed with the incoming air and filled the cylinders. If you used compression ratios as high as diesels, you would get premature explosions, i.e. knocking. That's why the ratios are lower and that's why you need a spark plug to ignite it. Directly comparing the two engines at the same compression ratio, gasoline engines are more efficient (at least at ratios of around 10 to 15). It would be possible to make a gasoline engine with a ratio of 15 these days, since we have mastered direct injection in petrol engines as well, but that would stress the heads (and pistons) a whole lot more - petrol mixture burns at ~1200°C, while diesel does at ~800°C - a big difference. Plus the pressures would be very high, etc. It is possible in theory, but is not practical (emissions would be a b*tch as well, i think higher cylinder temps cause more NOx to form in the exhaust gases). EDIT: that's how i see it, but i could be wrong. Correct me if i am.
  12. 5 likes
    Flexible coupling are mostly used to protect the pipelines connected to any machines carrying fluids . It may be used for a pump or some engines carrying coolants through it. Another use of flexible coupling is to transmit power from an engine . If the coupling was rigid , it could transmit the vibration from the power producing engine. Mostly in four stroke marine propulsion engine flexible couplings are used to connect the flywheel and the intermediate shaft for rotating the propeller and prevents misalignment of the shaft. Mostly it is made of rubber.
  13. 5 likes
    CC means Cubic Centimeter, It basically denotes the Volume of Cylinder, whether it may be a car or Bike.Technically it's the Bore Diameter and the stroke length of the cylinder.If a car as 1.8L Engine it's nothing but 1800 cc..Hence More the cc, more the power nd torque.
  14. 5 likes
    The bush material would be of a softer material than the shaft/spindle that runs inside it, often bronze, even oil impregnated bronze. The reasons for using the bush are that the bush will wear out before the bearing or the shaft/spindle, therefore reducing the time and costs of replacing the bearing or shaft. It would usually be sensible to carry spare bronze bearings already made to size to allow for a fast replacement. Usually these bronze bearings would be turned up from a length of bronze bearing material, ask your bearing supplies company for it, and make a few up in one go on the lathe, then label them and put them somewhere you will find them again!
  15. 5 likes
    A forming process that adds a pattern on the exterior of a workpiece, either for cosmetic reasons or better handling. Knurling is a manufacturing process, typically conducted on a lathe, whereby a diamond-shaped pattern is cut or rolled into metal.
  16. 4 likes
    One thing we know. We can’t use fuel in liquid form during compression, because liquids are incompressible. Now we have option to use diesel in vapour form. At atmospheric pressure, boiling point of diesel is 250°c to 300°c. And diesel in fuel tank have temperature around 40°c to 50°c. So it is not possible to make vapors (as in carburetor of petrol engine).So, how can we convert diesel into vapour form?There are three options: 1. If we put liquid diesel into a medium having pressure less than vapour pressure of diesel, it means we create vacuum inside the cylinder. During suction stroke we have vacuum and we can convert the diesel into vapors, but during compression stroke we must avoid auto ignition due to high compression ratio. The one and the only way to avoid the auto ignition in such case is to reduce the compression ratio. Which is not possible (2nd law of thermodynamics, higher is the pressure more is the power) if we want to get power from engine. Another important reason for using higher compression ratio is to get higher expansion ratio (more piston displacement) thus more power with same fuel consumption.Work done = pressure (mean effective pressure) × piston cross-sectional area × piston displacement. But still if someone manages this miracle, how he overcomes condensation of diesel during compression stroke where the pressure goes up again. So drop this option. 2. Increase the temperature of liquid diesel before putting into engine cylinder which is possible but not reliable. We have to use pre-heaters, which cost energy consumption and makes vehicles bulky. 3. Put liquid diesel into high temperature air (greater than saturation temperature of diesel) and provide some time for heat exchanging between them. In practical air standard engines third option is perfect as we produce high temperatures by compression. But still we can't use spark plug for ignition, since mixture present in the cylinder is heterogeneous (somewhere mixture within ignition limits and somewhere not). Ignition by spark plug required homogenous air fuel mixture. Now we have only 1 option to ignite the diesel, that is; compresses the air and raised the temperature of air up to ignition temperature of diesel and inject the diesel in cylinder.
  17. 4 likes
    To protect the bolt hole, spread the load & forces evenly, as a spacer, protect the nut from crevice & galvanic corrosion.
  18. 4 likes
    Washers are used with mechanism for this, that forces on surface area spread evenly.
  19. 4 likes
    When we manufacture any product, usually we manufacture it by casting or forging process. To get a proper surface finish of that product we need a proper machining. At the time of maching a certain amount of material usually removed from the surface of the core product. For this reason a tolerance is needed over the designed dimension to maintain the actual dimension. Beside this reason, tolerances also kept to maintain the needed dimension after thermal expansion or contraction at the time of solidification during casting process.
  20. 4 likes
    Type Of Ignition: SI CI Cycle Of Operation Diesel Otto Dual Fuel Used Petrol Diesel Gas Electric Cooling method Air Water Oil Stokes 2 stoke 4 stroke No.Of Cylinders 1 2 3 4 6 8 12 16 Valve location L-head I-head F-Head T-head (Usually said as LIFT heads) Cylinder Nature V-type vertical opposed Radial Speed Low Medium High Lubrication method Wet sump Dry sump That's all folks, if found other than this, please leave a comment. I remember a type based on application, but it is not technical. So i left that type.
  21. 4 likes
    Diesel Engines we dont need the Spark Plug the Calorific value of the Diesel is more when compared with petrol Engine. For less colorific value we do not get more horse power. But diesel natually have more heat developed during combustion thus developing more power than petrol engines.
  22. 3 likes
    This is very much like asking which came first, the chicken or the egg! Without strain, you will have no stress. Without stress, you will have no strain. I can't see how it is possible to say one precedes the other. DrD
  23. 3 likes
    Disc Brakes and Drum Brakes If you've got a pre-70s aircooled Volkswagen, the chances are you've got drum brakes on all wheels. If you've got a '70s model, you might have front disc brakes, and rear drums if you have certain Type 3's, a Super Beetle (AKA 1302 or 1303) or Karmann Ghia with 1600cc engine. So, what are the differences, and why were disc brakes brought in? Let's have a quick look at both types. Drum Brakes So called because the braking part is drum-shaped. Inside the drum, two large, curved brake pads push outwards, slowing you down. Below is a picture of the inside of a drum brake, once the drum itself is removed. The drum itself is a relatively uninteresting, slightly rusty, dish-shaped lump of metal which the wheel bolts on to. The rim of the drum is about two inches deep, completely covering everything you can see in the picture. At the top of the picture is a 'slave cylinder' which pushes the two brake pads outwards when you press the brake pedal. The pads rub against the inside of the drum, and the friction slows you down. Drum brakes are good because they're simple (although not when you're trying to put them back together) and reliable. However, they have a couple of bad drawbacks: if you go through some water, they are very ineffective until the water has drained out of the drum; and they get less efficient as they get hot. When they get hot the drum expands, growing further away from the pads, so you have to press the pedal further down to get the same amount of braking, and if they get hot enough you get very little braking at all. This is very bad news if you're driving down the side of a mountain on a switchback road, and not much better if you've been thrashing it around some country roads and need to stop suddenly. Disc Brakes Working somewhat like bicycle brakes, disc brakes work by using calipers to clamp brake pads against either side of the spinning disc. (The disc brake above is from a custom VW Beetle seen at a show, yours probably won't look as fancy.) Disc brakes are good because when they warm up, the disc gets larger and is therefore closer to the pads, meaning you don't have to push as hard on the pedal to get good braking. Also if you drive through water, it just falls off the disc so you get your stopping power back very quickly. They're also generally more efficient than drum brakes and are easier to set up. You may hear about 'cross drilled' disc brakes, this means they have small holes drilled through the face of the disc as in the picture above. The holes were originally designed to help remove gas caused by brake pads heating up, but with modern pads being much more resilient they are just there for show. Why are Drums still around? So if disc brakes are so marvellous, why are drum brakes still around? Well, disc brakes work only through hydraulics, which make them very tricky to use for hand brakes (that's 'emergency' brakes to Americans.) If you try to clamp a disc brake, as it cools down after use the disc gets slightly smaller, which means the car has to gradually increase the amount of force on the brakes to keep the car still. This is a tricker - and therefore more expensive - job than it sounds, whereas a drum brake can be held on by a cable, and usually are. Many modern cars, e.g. the VW Touran, still come with front disc brakes and rear drum brakes, and some sports cars still have a small drum brake attached to the rear brakes to act as the handbrake, although they have rear discs for the most efficient braking. If you own an aircooled Volkswagen, please rest assured that if your car came with all-round drum brakes then they are good enough to stop it within current safety distances. My Beetle only has drums, and when properly adjusted they stop the car better than a poorly maintained car with discs. However, if you're fitting bigger, non-standard engines I'd look at fitting disc brakes, either from a donor VW or using an after-market kit. Speed is great, but stopping yourself before becoming an accident is even better.
  24. 3 likes
    CC stands for "Cubic Centimeter". It basically measures the swept volume of the cylinder. The more the CC more fuel will be able to burn hence providing more power. CC=VOLUME OF CYLINDER/NO.OF CYLINDER
  25. 3 likes
    it is using in application witch have limited varying in transmitted torque such as pumps this couplings have a advantage: 1- it is can be absorbed little vibration witch is generate due to small misalignment 2- it is contain a (shims) witch be a weakest point for damage to protect shafts from suddenly torque
  26. 3 likes
    S.K.Das Gupta-I think the question itself needs to be modified as "What is the advantage of providing a bush in a bearing housing in place of bush in a bearing. In fact ,the selection of bush bearing or anti friction bearing in a machine depends on the requirement.For example.in a crank shaft of an engine,the big end bearing can be fitted in two halves only.Hence a bush bearing in two halves is used.There is also a space consideration for the machine as anti friction bearing normally needs more space.Also,for very high speed machines,foil bearings are being used as these are very efficient and having a very long life.These days many bush bearings are being replaced with anti friction bearings to get better life and ease of maintenance.So in a nut cell,using a bush bearing/anti friction bearing depends on the function of the machines,it's operating condition,lubricant requirement,space for bearing mounting and many other factors. Material of bush may be phosphor bronze,gunmetal,cast iron,thermit or white metal,teflon etc.
  27. 3 likes
    When you say "nomenclature," I presume you are speaking of the specifictions (dimensions, materials). Based on that understanding, I think the answer is, with only that, you cannot evaluate the torque. You need to know a good bit about the combustion process that takes place, and that requires a knowledge of the fuels, the temperatures, and a lot of thermodynamics. If you have a credible P-V diagram for the engine at the operating point of interest, then a dynamic analysis of the engine can provide the output torque, based on that P-V diagram. It is not simple, and it requires quite a lot of calculation, but it can be done with some accuracy. But, and this is a big but, it will only be as good as the P-V data you start with.
  28. 3 likes
    To allow slip and creep chain drive is used over belt or rope drive. To get accurate rotational timing a chain drive is best replacement for belt drive. Pro's of chain drive over belt drive 1) It can be used for accurate rotational timing thus used in I.C. Engines as timing chain. 2) There is no loss of energy in the form of heat because no slip and creep occurs. 3) Better service than belt drive. Con's of chain drive over belt or rope drive 1) Initial cost is more than belt drive system 2) Require proper lubrication for smooth functioning. 3) Not silent as belt drive in absence of lubrication. 4) Catches rust easily.
  29. 3 likes
    Initially, cost!....no need for expensive or complicated ducting of the exhaust gasses. Minimisation of fire risk (as said above) Due to the "enhanced ventilation" available in the early tractors (ie there was no enclosed "cab") there was no need to prevent a build-up of exhaust gasses around the cab. Diffusion of highly flammable dusts (such as during harvest) reaches a lower ignition/explosion risk at slightly higher levels. Prevention of both grounding and blockage due to the environment. No exhaust blowing onto the pickers/packages following the tractor. Probably a few more to boot!
  30. 3 likes
    1. Measuring Inside Dimensions The upper set of jaws on the caliper can be used to measure inside dimensions, such as the diameter of holes on a piece of wood or metal. Measuring the precise diameters of holes in pipes, cylinders and other hollow objects is very important to any project or application. The jaws of the caliper can be easily slid into the hole to get the precise measurement. The caliper can also be used to measure inside dimension of holes with different shapes, e.g. square, rectangular, cylindrical, or hexagonal. Lastly, the upper jaws can be used to measure the distance between 2 objects. This can be done by simply putting the jaws of the caliper between the objects to get a measurement. 2. Measuring Outside Dimensions The lower set of jaws on the Vernier caliper can be used to measure outside dimensions. Outside dimensions include the outer diameter of a cylinder and total length of an object. The outer diameter of cylindrical objects can be measured by simply clamping the lower jaws of the caliper around the object. The caliper can also measure the length or width of an object by placing the object between the caliper’s jaws. 3. Measuring Depth The Vernier caliper has a depth probe on the rear part. This probe can be extended from the edge of the hole to the other end of the hole. With the depth probe, one can measure the precise depth of a hole in any piece of wood or metal.
  31. 3 likes
    governor help to regulate the fuel supply according to the speed variations and flywheel stores energy during every cycle of engine
  32. 2 likes
    Thanks, JAG, for a most useful, real life, lesson. I've seen it myself, and I know the problem is very real. I think it is partly intellectual laziness, and partly a desire to be a part of the "in group,' that is, those "in the know." If I speak in acronyms, it looks like I know what I'm talking about, even if the actual content of my speech is foolishness. No one can be quite sure what I said, and if I speak with authority, who will challenge me? Great note!! DrD
  33. 2 likes
    The mechanical properties of a material are those properties that involve a reaction to an applied load. The mechanical properties of metals determine the range of usefulness of a material and establish the service life that can be expected. Mechanical properties are also used to help classify and identify material. STRENGTH: The strength of a material is its ability to withstand an applied load without failure or plastic deformation.In machine design yield point or ultimate tensile / shear / compressive strength is used while designing. Stiffness: Stiffness is the rigidity of an object — the extent to which it resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Hardness: Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a compressive force is applied. Some materials (e.g. metals) are harder than others (e.g. plastics). Elasticity: the ability of an object or material to resume its normal shape after being stretched or compressed. On a stress-strain diagram it is considered to be below proportional limit.But widely this point is taken as the yield point by drawing a line offset by 0.2% parallel to the straight line until it intersects the curve. Plasticity: It describes the deformation of a (solid) material undergoing non-reversible changes of shape in response to applied forces. Brittleness: A material is brittle if, when subjected to stress, it breaks without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength.
  34. 2 likes
    Knocking occurs before ignition and detonation ovcurs after ignition due to unburnt fuels
  35. 2 likes
    There are lots of them out there, just to name a few: . Maximum principal stress theory (Rankine's theory) Maximum shear stress theory (Guest's theory) Maximum principal strain theory (Saint's theory) Maximum strain energy theory (Haigh's theory) Maximum distortion energy theory (Hencky&Von Mises theory) This presentation is a good starting point.
  36. 2 likes
    Soldering and Brazing are similar metal joining process. Soldering uses a filler material alloy of tin and lead that melts below 425°C. Brazing uses alloys of Silver or copper that melts above 425°C. Brazing is used when strength requirements are greater offers higher resistance to corrosion and pleasing aesthetics. Source: "Design for Manufacturability Handbook", 2nd Ed., James G. Bralla, Ch 7.4 Solder and Brazed Assemblies
  37. 2 likes
    it help to lessen the counter forces produce by vibration, to aligned all forces toward center and perpendicular to flat surface thus give optimum fastening strenght e.g. bolt and nuts with washer.
  38. 2 likes
    It depends on the where the flow is taking place 1.IN CASE OF FLAT PLAT Laminar flow when Re<5,00,000 Turblent flow when Re>10^(7) 2.IN CASE OF PIPE LINE Laminar Re<2000 Transient 2000 Turbulent Re>4000
  39. 2 likes
    Screw Jack :- Is a mechanical device used in applications where linear motion is required. Lifting of any load, pushing or pulling of mechanical equipment, adjusting of tight clearances of mechanical parts can be done by screw jacks. Mechanical capacity of screw jacks is between 5kN and 2000kN. Jack screws can be used as linear motors, linear actuators, or mechanical lifts depending on type of motio
  40. 2 likes
  41. 2 likes
    digital twin spark ignition system uses two spark plugs which alternatively spark and make the process of combustion an istantaneous one which results in complete combustion and fuel benifits
  42. 2 likes
    the above answers are valid when the fluid flow occurs inside a pipe and its value varies based on type of fluid and flow conditions.
  43. 2 likes
    well i think...compressor simply forces the fluid particles in a specified reservior...i,e somewat inc the density of fluid. while pump is just to inc the absolute pressure of the fluid...... plz correct me if i m wrong..
  44. 1 like
  45. 1 like
    Difference between Turbocharger and Supercharger in Tabular Form S.no Turbocharger Supercharger 1. Turbocharger is a forced induction system that compresses the atmospheric gases and sends it to the engine cylinder. Super charger is also a forced induction system. It compresses the atmospheric air and sends it to the engine cylinder. 2. It uses exhaust gases for its energy. It is connected to the crankshaft of the engine for its energy. 3. It is not directly connected to the engine. It is directly connected to the engine through belt. 4. It has smog altering equipment which helps in lowering the carbon emission. It doesn’t have wastegate, so the smog emits from the supercharger. 5. It spins with a speed upto 150000 rpm. It spins with a speed upto 50000 rpm. 6. It is much quieter than supercharger. It is not so quieter. 7. It is less reliable. It is more reliable. 8. Maintenance is not easy. Maintenance is easy. 9. Turbocharger delivers their boost better at high rpm. Supercharger can deliver their boost at lower rpm. 10. It is more efficient. It is less efficient. 11. The compressed air in turbocharger has high temperature. The compressed air in supercharger has less temperature. 12. It requires intercooler for the compressed air to lower its temperature. It may or may not require intercooler. But in some types, it requires intercooler. 13. It is more complex. It is less complex. 14. It has lag problem due to discontinuous supply of energy. It has negligible lag problem because of continuous supply of energy by crankshaft. 15. The compressor is rotated by the turbine. The compressor is rotated by the engine crankshaft through a belt.
  46. 1 like
    In some senses, this question is like asking the difference between dogs and cats. They are simply different animals. The operate differently. Yes, both require an electrical input, but even that is not the same for both. It is not possible to give a simple, one paragraph explanation of how each works. Most folks accept that they are different, and if you really want to know how one or the other works, you have to get in and dig through the analysis. DrD
  47. 1 like
    spark ignition engines due to exhaust system idle rpm exhaust pipe diameter crank weight turbocharger strokes piston length and diameter of piston aging firing order nature of engine sporty or crusie compression ratio muffler method of injection direct or carburator
  48. 1 like
    Dear Daniel, You ask "What is the name of this mechanism?" but your videos/pictures show many mechanisms in action. Just which part are you asking about? Most of this looks like cam driven motions, with a follower moving in a vertical guide while the cam drives the follower up and down. Please describe your interests in more detail so that we may try to give a better answer. DrD
  49. 1 like
    CC is the Cubic Liters of the Engine. We calculate the bore diameter and Cylinder size and multiply them the result we get t is the CC (cubic centimeter of the Engine) 2.0 L that means is 2000 CC Engine. The total volume we get is 2000 Cubic centimeter.
  50. 1 like
    Governor regulates fuel which is supplied in the cylinder whereas flywheel is installed in crankshaft and its function is to store energy during power stroke and helps maintain smooth transition.of power