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  1. 3 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
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    Why slenderness ratio is considered in design of members? 1. You can answer this question 2. You can like the best answer 3. You can share the question.
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    Air cooled, liquid cooled, carburated or fuel injected, Direct injection, Air filter design, inlet roar, ohv or ohc, hydraulic valve adjustment, shimmed tapets manual tappet asjustment. How many more reasons for different engine sounds do you want
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    Why do mechanical components fail? List down - Theories of Failure 1. You can answer this question 2. You can like the best answer 3. You can share the question.
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    Free, cost $10 - funny. I have a few versions of Free CAD that was actually free. I wonder if the later versions are now sold.
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    Following are the reasonable points that conclude the high torque and efficiency of diesel engine. Diesel engine uses simple mechanism for combustion unlike in gasoline engine. Removal of ignition system not only makes the mechanism simpler but also reduces the risk of improper combustion due to damage in ignition system. In short burning of the fuel is easy and always accessible. This results in higher efficiency diesel engine. Diesel fuel is a heavier hydrocarbon in which carbon and hydrogen are strongly bonded with each other. And when energy is supplied in form of heat it gets explode releasing much higher energy then gasoline. In short diesel fuel has higher energy density then gasoline which results in huge explosion. One more factor for higher efficiency in diesel engine is its property of lubrication. Although all fuel has property of lubrication but diesel fuel has much higher lubrication then gasoline fuel. The compression ratio is much higher in diesel as compared to gasoline because in diesel engine air is alone compressed inside the cylinder and it’s a known fact that gas easily compresses then liquid. This is not so in gasoline engine because air-fuel mixture is compressed inside the cylinder. This higher compression gives higher heat and simultaneously higher torque. We can’t use Carnot cycle to get 100% efficiency but can use its principle to attain maximize efficiency. In diesel engine heat is added at constant pressure which results in higher utilization of heat energy to get maximize work output. These were the advantageous features of diesel engine but it has some demerits as well like it releases highly toxic gases, noisy, higher maintenance cost and starting problem (now starting problem is eliminated by using a bulb nearby to the cylinder) to heat the engine before ignition. And it is costlierthan gasoline engine but with optimum operation and good maintenance resolve all these problems.
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    Rankine cycle: transition from isobar to adiabatic process. Carnot cycle: transition from isothermal to adiabatic process.
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    Turbo charger and super charger increase the compression ratio in an engine without changing cylinder and piston dimensions. In other words we can say super charger or turbo charger increases air density at intake manifold of the engine. Difference between Turbocharger and supercharger. Both perform same function but their driving mechanism is different. Super charger utilizes engine power for operation by coupling with engine rotary source. While Turbo charger use waste exhaust gas pressure and flow in order to rotate and produce air charge to intake manifold.
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    " "I think the human race made a big mistake at the beginning of the industrial revolution, we leaped for the mechanical things, people need the use of their hands to feel creative." - Andre Norton" Feel free to reject all the products of the industrial revolution in your own life. Do not ride in automobiles, do not use electricity, do not use any machine of any type, and of goodness sakes, do not use a computer. Just go live in a cave or a mud hut, (no lumber, nails, screws, or glue allowed), burn only wood or cow chips, and do not eat anything cultivated or processed by machinery. This would be a good start, and then I'm sure you will find ways to improve on this beginning. Enjoy your life!!! DrD
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    What is the exact difference between refrigerator and a air conditioner ? 1. You can answer this question 2. You can like the best answer
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    "I think the human race made a big mistake at the beginning of the industrial revolution, we leaped for the mechanical things, people need the use of their hands to feel creative." - Andre Norton
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    Why worm gear drive is used for hoists ? 1. You can answer this question 2. You can like the best answer 3. You can share the question.
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    Go through this link http://www.skf.com/in/products/bearings-units-housings/ball-bearings/principles/selecting-bearing-size/bearing-life/load-ratings/index.html
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    Darcy–Weisbach equation gives the value of head difference or in case of flow, loss of head in the turbulent flow through pipes due to frictional factors, this equation gives this in terms of all the measurable quantities and is derived from the equation of velocity profile. Head loss hf = ((P1 - P2)/(density x g)). Hence is of much importance in experimental works, dimensional analysis and model analysis of flows.
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    With regard to materials, you must stay away from most metals, and especially aluminium. They will corrode rapidly in a salt water environment and lose strength accordingly. Think more of polyesters and epoxy materials. Are we to understand that rotation is in a horizontal or vertical plane? Assuming a horizontal plane for the rotation, you will need an airfoil shape, as the turning force is developed by hydrodynamic forces. Where will you generate power, below the water or above? This is a difficult problem, one that I worked on for the US Navy some years ago. You have a lot of hurdles to face to get this to work. DrD
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    State difference between AnitiFriction Bearing and Journal Bearing? 1. You can answer this question 2. You can like the best answer 3. You can share the question...
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    What is an injector pressure in heavy vehicles? Why it is used? 1. You can answer this question 2. You can like the best answer 3. You can share the question.
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    Why tyres are made black in color? 1. You can answer this question 2. You can like the best answer 3. You can share the question.
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    Is P the number of planets, or the number of teeth on a planet gear? If it is the number of planets, I don't think it is true at all; at least, I do not see it. DrD PS: Remember that, for gears that actually mesh, the number of teeth on the two gears are each proportional to the pitch radii of the gears.
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    I"m glad to hear that you found something useful, Tim. It is almost comic that the name is FreeCAD, but it costs $10. I wonder what it would cost if it were called PayForItCAD? DrD
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    A shaft is a power transmission device, connected to a gear or coupler on both ends. An axle may or may not transmit power. An axle may just be used for a center of rotation on non-driven wheels such as the front wheel of a motorcycle. An axle may or may not be a shaft.
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    1. What are the differences between true stress, engineering stress, proof stress. 2. What do you men by factor of safety and what is its significance 3. What do you mean by Young’s modulus, modulus of rigidity and bulk modulus. 4. What do you mean by resilience. 5. What is pure torsion and what do you mean by flexural igidity. 6. What is the difference between endurance limit stree and endurance strength. 7. What do you understand by efficiency of riveted joint. 8. What is caulking and fullering in riveted joint. 9. What do you mean by stress conc. Factor and what are the methods to reduce stress conc. 10. Why stress conc. Is more serious in brittle materials. 11. What do you mean by fatigue . 12. Springs are subjected to which type of streses. 13. What are the difference between through bolt, tap bolt and stud. 14. What is check nut and what is the function of washer. 15. Cotter and knuckle joints take which type of load and where they are used. 16. What are the difference types of couplings and what is their function. 17. What is the function of key and which type of stress they are subjected to? 18. Generally shafts are subjected to which type of stress. 19. What are the difference types of mechanical drives and which is the best for different situations. 20. What is the function of a bush why it is phosphor bronze. 21. What are difference types of threads and which threads are used for power transmission and why. 22. Why the pulley arms are elliptical in cross section and it is made up of cast iron. 23. Why it is required to change the all V belt if one of them is broken. 24. Why V belts transmit more power than flat belts. 25. What is the meaning of 6*37 or 6*7 in a rope drive. 26. What do you mean by pinion sprocket and wheel sprocket and which one is used for driving shaft. 27. What is the function of flywheel and why its material is cast iron. 28. Why the leaf springs are laminated as reducing length. 29. What is the function of clutch and is the difference between uniform wear and uniform pressure. 30. Now a days which type of clutches are used in automobiles. 31. Why disc brake is more efficient than mechanical brake. 32. What is the function of bearings and what are the different types. 33. What is bearing characteristics number and bearing modulus. 34. What is the significance of the digits of a rolling contact bearing number 6304? 35. Which type of gear drive is used for perpendicular transmission of power? 36. Why helical gears transmit more power than spur gears. 37. What do you mean by different terms like back lash, pressure angle, circular pitch in a gear drive. 38. Why involute tooth profile is better than cycloid tooth profile? 39. What is interference in gear drive and how to avoid it? 40. What do you mean by law of gearing
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    Diesel or kerosene has no spark plug due to its higher volatility and flash point. The spark plug and voltage needed for ignition would be very large. So the atomized fuel-air mixture is ignited (adiabatic heating) by superheated, compressed air. The compression ratio for diesel is higher to ensure more complete combustion, which helps it have a much improved thermal efficiency over CI engines.
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    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.
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    Because here ignition takes place at a very high compression ratio where the temperature is high enough for self ignition of the diesel(fire point) air mixture to takes place....
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    In Lathe, if turning Operation is considered, Primary parameters are Feed(f) in mm/rev, cutting speed(v) in m/s, depth of cut(d) in mm.
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    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!
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    Difference in sound is observed because of following Reasons Type of Engine - Two Stroke/ Four Stroke Number of cylinders ( Normally 1 in all bikes but have more than 1 in some big brands) Design of exhaust Different Engine RPM Range Engine Geometry
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    To burn fuel properly inside the cylinder fine sprays are required, so high pressure is required to inject the fuel through fine holes of injectors. Injector pressure is the pressure by which fuel is injected in a D.I. Engine. Injector pressure is different for different engines, depends on the design of engine, combustion chamber etc.
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    There are three basic power steering systems in use today – i) Hydraulic, ii) Electro-Hydraulic and iii) All Electric. As they say, there are no free lunches in this world. All the three eventually derive their power input requirements ultimately from the Engine, either being directly powered off its Crankshaft OR the Car Battery/Alternator. Of the three, The Hydraulic one is the most time-tested and Popular, as it can be applied from a Small Car to a Giant Earth Mover. However, by virtue of the nature of its design, it’s more maintenance prone and a little less energy-efficient. On the other hand, an All Electric ones presently have their application limited to Passenger Cars – weighing, say, from 750 kgs to 1500 kgs or so. This is coz it primarily depends on the Car’s Battery to Power it, which in turn depends on the Engine driven Alternator to charge it back. Since it can be ‘Computer Assisted’, it can very easily be programmed to any desired ‘spectrum’ of ‘Assist’. Since there are fewer moving parts in it and can be virtually made ‘idle’ at straight cruise conditions, it’s more ‘direct’ and Energy Efficient. An Electro-Hydraulic System is a ‘cross’ between the two, by way of advantages and disadvantages and doesn’t seem to be much popular these days, presumably from initial cost considerations
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    Do see these 2 presentations for detail understanding of "theories of failure"
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    Supercharger , the engine booster. Why supercharger ?? How it works ??? Working diagram of supercharger. Classification of supercharger. History. Roots supercharger. Twin-Screw Supercharger. Centrifugal Supercharger. Drives used in Supercharger. Supercharger, An edge over turbocharger Nothing is perfect. Conclusion.
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    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.