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Engineering Discpline

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  1. What's new in this club
  2. Anyone who has a thesis either capstones or experimental. I would gladly appreciate it, I am a 3rd year student studying mechanical engineering course. As part of our research development, we had assigned to look for any research thesis. Anyone who can helped, Thank You Very Much In Advanced. google is helpful but not in this topic because various parts is needed such as introduction, literature review, methodology, results and discussion, summary, and bibliography.
  3. Gasoline, or petrol, ignites too soon (predetonation) in a diesel engine due to diesel engines high compression ratios. That causes some reverse loading, very high stresses, mostly on the cylinder rods which may eventually fail in high compression load and bearing wear. Multifuel engines must be designed for extra high rod loads.
  4. You’re all right, but there are multi fuel outboard engines (based on petrol engine design) used in defence running on various fuels, kerosene, jet fuel or diesel (low compression ratio with spark plug support). Downside is that the engines are not compliant to enviro regulations, due to incomplete combustion (engines are “Smokey”). See Mercury Racing Optimax JP and Evinrude E-TEC.
  5. Compression Ratios are also very different, Diesel run with compression ratios from 17~21 to 1 where gasoline engines can only run at compression Ratios of 8~11 to 1. Gasoline will detonate at much lower compression than what is needed for diesel to reach self ignition point. A real diesel engine will be more efficient overall since it will have the ability to operate at higher compression ratios. If a petrol engine were to have the same compression ratio, then knocking (self-ignition) would occur and this would severely reduce the efficiency, whereas in a diesel engine, the self ignition is the desired behavior.
  6. we cannot use petrol in diesel engines or vice versa because diesel and petrol has different characteristics (flashpoint) every engine has unique design depends on its fuel to be use. petrol and diesel engine has different engine stroke cycle specially during intake and ignition stroke Diesel intake stroke: enters hot air ignition during power stroke: sprays pressurised diesel fuel on the combustion chamber by means of injection nozzle gasoline/petrol intake stroke: enters air and fuel mixtures by means of carburator ignition during power stroke: ignites by means of sparkplug sparks inside combustion chamber @ highly compressed air and fuel mixtures
  7. The flash point of petrol is high also the compression ratio, spark plug used for Petrol engine, valves used for injection of fuel in diesel, is it OK
  8. I don't know how to install or get the Auto Cad software for free. If anyone of us is aware of this please tell us, so we can learn quick with the tutorial and software. Thank-you 😊
  9. Well, it can't be entirely fixed whether the Re range under which the flows are classified. In convention, for internal flows, Re < 2000 is regarded to be laminar 2000 < Re < 4000 is regarded to be transitional flow Re > 4000 is most often turbulent. On the other hand, for external flows, Re > 5E5 is said to be turbulent
  10. It is not preferred to weld material in normal atmospheric gases, either we need to provide any shielding gas or produce it while welding; so that the weld can be done without any impurities. These impurities or oxides (formed in contamination with oxygen at high temp.) decreases the mechanical property of the metal or alloy which may effect the same in long run. There are many kind of shielding gases out of which few are inert and others are semi-inert gases, which basically doesn't produce any harm to the metal during welding moreover they protects the metal from contamination by other gases. Inert gases basically used are Argon and helium gases; whereas semi inert gases are nitrogen, carbon dioxide etc. Basically a beam of non-reactive nitrogen gas is thrown at the welding to shield the weld so that no oxide formation takes place. This increases the weld penetration and arc stability. Moreover nitrogen helps in prevention of metal/alloy from pitting and nitrogen loss from metal. Hence increasing the metallic property of metal.
  11. Overdrive or OD is the highest gear in the transmission in an automatic car. It brings the RPM of the engine down at a given road speed to facilitate better speed and fuel efficiency. It also helps your car to provide the best performance in higher speed cruising. Overdrive helps when you drive at more than 50mph.
  12. To check your score Take the quiz https://engineeringtalks.com/quizzes/quiz/43-mechanical-engineering-concepts-quiz-1/
  13. Explain what are the approach used in manufacturing for QA?
  14. Disk brakes work on hydraulic (liquid power) system where in pressure is created on a disk attached to the freewheel. the fluid pushes the brake shoes from both sides of the disk which brings the disk to stop (naturally the wheel to stop). It is just like the way you hold a spinning disk by your hand. It is visible from the outside (obvious). Drum brakes are not visible from outside. they form the center of your flywheel. the basic idea is that if the center of the wheel stops, the wheel obviously stops. This mechanism works mechanically (using wire). The break shoes aren't visible from outside they are in the drum (center of the wheel). when brakes are applied, the string/wire pushes the break shoes against the inner side of the drum bringing the wheel to a halt. Drum breaks and Disk breaks have no difference in their effectiveness. They are both effective. It is just the design which suits the bike/car. Disk brakes look shiny giving complimenting the rims and giving it a elegant look.
  15. Disc brakes are made up of a brake caliper, two brake pads and a flat metal rotor that spins in tandem with the wheel. When the driver applies the brakes, the caliper squeezes the brake pads onto the rotor. This causes friction that slows the spinning of the wheel. It's only loss it's high expensive nd benefits are given below Less brake fade. Better performance in wet condition. Less likely to lock up. A drum brake consists of a small round drum that contains pistons and two brake shoes. The drum rotates next to the car’s wheel. When the driver depresses the brake pedal, pressurized brake fluid is sent to the drum brake, and it forces the pistons to push into the brake shoes. This action causes the brake shoes to press against the sides of the drum, creating friction that slows the spinning of the wheel. benefits it's less expensive .it's loss are given below 1.Less effective at dissipating heat. 2.Less effective in wet conditions. In wet conditions, water has a tendency to pool inside drum brakes. This negatively impacts braking performance.
  16. ANSI 1020-1050 steels are most common materials for industrial shafts, depending on situation and exploitation other materials are used for example other common material is 42CrMo4 for heavy load since it's tensile strength can reach even 1200 MPa. Generally low to medium carbon steels with high tensile strength and hardness (500-1300 MPa). Usually it's hot rolled or cast depending on dimensions and load. Depending on steel and use heat treatment is prescribed, sometimes just hardening (not all steels), sometimes chrome plating, sometimes boron or nickle plating...
  17. Quality assurance it Good materiał, stabilized process, machines in Good condition nad most important- Staff. Quality Control it is only confirmation that above work correctly 😎
  18. Hydraulics is used where output work requirement is more whereas in pneumatic system load demand is less
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