What is Engines: Definition and 301 Discussions

An engine or motor is a machine designed to convert one form of energy into mechanical energy. Heat engines convert heat into work via various thermodynamic processes. The internal combustion engine is perhaps the most common example of a heat engine, in which heat from the combustion of a fuel causes rapid pressurisation of the gaseous combustion products in the combustion chamber, causing them to expand and drive a piston, which turns a crankshaft. Electric motors convert electrical energy into mechanical motion, pneumatic motors use compressed air, and clockwork motors in wind-up toys use elastic energy. In biological systems, molecular motors, like myosins in muscles, use chemical energy to create forces and ultimately motion.

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  1. R

    HHO Generator Design for 6.4L V8 Engines

    Has anyone come up with a design for an HBO generator to run an engine just on hho? How many lpm would I need to produce to run a 6.4 litre v8
  2. P

    Noise Shielding by Rear-Mounted Engines on Aircraft

    How is the noise sheilding provided by the fuselage when the engines are mounted at the rear end of the aircraft ? for example-SAX 40
  3. B

    Questions about Jet Engines: F-14, F-105 and X-51 Waverider

    Hello, I have a question regarding jet engines. Fighter craft such as the F-14, and more obviously (from a visual stand point) the F-105 have some sort of device that controls air flowing to the compressor. Apparently the air must be slowed to subsonic speeds in order to avoid stalling the...
  4. M

    Connecting Rod Failure in 4 Stroke Petrol Engines

    hi.. I am new to this site. I want to know about reasons of failure of connecting rod of 4 stroke petrol engine. In this case the rod has broken into two parts from the small end of the rod. The manufacturing root of the component is hot forging - hardening - induction softening of the small...
  5. E

    Calculating Thrust in Propeller Engines: Can Anyone Help?

    Can anyone help me? I'm doing a question on aircraft propulsion technology and I'm stuck. The question is: 'If the mass of air through a propeller is 1000 Kg/s, the aircraft's velocity is 100 m/s and the slipstream velocity is 120 m/s, calculate the thrust? Attempt at answer...
  6. A

    Developments in turbofan engines

    hello, My name is vinod, I am student and currently I am doing a project on developments in turbofan engines. I want to know the developments taking place in the turbofan engines with respect to efficiency and noise. Also, I want to know more about propfan (unducted turbofan) engines, can...
  7. C

    Do stirling engines have a pressure gradient across the regenerator?

    There is a temperature difference and we know the transition of the working fluid (from the hot chamber to the cold one) is isometric. So either there must be a pressure difference, or the number of molecules must be smaller; however, this can't be the case since eventually all the gas must move...
  8. kandelabr

    Two IC engines with same displacement, but different number of cylinders

    Homework Statement The object of this assignment is to find two engines that have the same displacement and different number of cylinders and compare ratio of their power output to a few equations' results. The engines should be from the same manufacturer and their manufacturing date should...
  9. R

    Why is gasoline preferred over diesel for cars?

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  10. K

    A question about long-stroke or undersquare engines

    As i have read in several articles, it is obvious that short-stroke or oversquare engines can rev higher and produce more power and less torque and usually used in sports cars but long-stroke engines are good for high low end torque and can't rev as high as short-stroke engines. But i have...
  11. Redbelly98

    Phase change in heat engines & heat pumps

    This question has been in the back of my mind for a while. In short, is having a phase change between liquid and vapor more desirable for a heat engine or for a heat pump? Clearly, having a large area enclosed by the loop in a P-V diagram increased the amount of work in the cycle, so...
  12. T

    Where should I post questions about Stirling Engines?

    Where should I post questions about how to make a DIY Stirling Engine work?
  13. M

    Engines: Torque Lost To Friction

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  14. G

    Why is 100% efficiency impossible for heat engines?

    My question involves heat engines. I understand that a heat engine typically uses energy provided in the form of heat to do work. According to the 2nd law of thermodynamics, however, not all heat energy can be converted into work energy, meaning that heat engines are not perfect. At least some...
  15. B

    Reversible & non reversible internal combustion engines

    Please can someone explain clearly in perhaps lay man terms the difference between REVERSIBLE & NON REVERSIBLE INTERNAL COMBUSTION ENGINES. Thanks
  16. C

    Need help with a question involving heat engines, the carnot cycle and entropy.

    The Attempt at a Solution For a) I imagine it is easier to control the temperature of the hot reservoir because you could use a constant heat source e.g. bunsen burner. c) melting/freezing water. d) Entropy of the environment increases and the entropy of the universe always increases...
  17. M

    Heat Engines and exhaust heat

    Homework Statement A heat engine operates between 40°C and 380°C. Being a real engine, its efficiency is only 60% of that theoretically possible for a Carnot engine at these temperatures. If it absorbs heat at a rate of 60 kW, at what rate does it exhaust heat? Homework...
  18. D

    Why Jet Engines are Attached to Airplane Wings

    why jet engines are attached to the wings of the airplane ,not other part?:confused:
  19. C

    What Temperatures Do IC Engines Operate At? Find Out Here!

    can someone tell me what temperatures ic engines generally operate at?
  20. M

    Can Microprocessors Operate Modern Engines?

    i read that motors can be operated by interfacing them with micoprocessors(stepper motor),so can this be done with modern day engines?
  21. C

    Exploring Deuterium Engines: Seeking Help

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  22. C

    Are Deuterium Engines the Future of Space Travel?

    Hello all, I am an amateur science fiction writer and am currently working on a novel. I am exploring the possibility of deuterium engines and am having a bit of a difficult time understanding some of the research that I have been coming across, as I do not have a very large science...
  23. B

    Thermo - Heat Engines, Heat Pumps

    So I wrote my Thermodynamics final today and one of the questions were as follows: A reversible heat engine supplies a reversible heat pump. Both draw off of a temperature reservoir T (can't remember the exact value, but there was one). The heat engine discharges heat into TL, and the heat...
  24. P

    Thermodynamics - Need Help on Turbine Engines

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  25. DaveC426913

    Online gaming engines as a commodity

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  26. M

    Advantage of many-V engines over V-twin engines

    What is the advantage of a big V engine over a V-twin engine? Why not just use extra-large V-twin engines instead of using V-12 engines and such?
  27. Z

    Minimum thrust of engines at lift-off

    Homework Statement Hi there Rocket has a total mass of 3.4 x 10^6 kg at lift-off. The first stage contains 2.0 x 10^6 kg of propellants which is consumed at a rate of 1.4 x 10^4 kg s Find the minimum thrust of the engines at lift-off? I would have thought that you needed one more...
  28. T

    Is Cooling the Key to Efficient Jet Engines?

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  29. 2

    Thermodynamics: Carnot engines

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  30. J

    Understanding liquid fueled rocket engines

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  31. R

    Advantages/Disadvantages of V-8 vs V-12 6.0L Engines

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  32. T

    Can Barbra Streisand Dummies Prevent Bird Strikes on Airplanes?

    I know that a lot of plane crashes were caused by birds being sucked into an engine (e.g. the Hudson River Landing). Is there a way around the problem? I know that no solution is out there so what are some things that's stopping it?
  33. D

    Are there any engines that defy traditional design and function?

    I am starting this for a couple reasons. First is that I wanted to post a link to a tech article on Smokey Yunicks engine. Popular mechanics article on good, old, google books, search: smokeys engine. link below (hope it works)...
  34. V

    Turbofan Engines: Bypass Ratio Selection Criteria

    What Basis Bypass Ratio Has Chosen For Turbofan Engine
  35. M

    Focus mainly on Jet engines

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  36. B

    Wanting to study engines and other vehicle mechanisms

    I've always been fascinated by and wanted to know more about the internals of a car: everything from the engine to the transmission to the suspension and the chassis. Currently I am a year 1 ME student, so I don't have enough physics knowledge to study the logistics in depth in that regard...
  37. S

    What is Tubes Assembly and Manifold for engines?

    Dear all, I am so sorry for my stupid questions. Currently, I am looking for documents (lecture notes) on tubes assembly and manifold for aircraft engine. What are those tubes assembly and manifold? What are those characteristic? I did quite a lot google search, however, I only found any good...
  38. D

    Maximizing Mass Airflow in Internal Combustion Engines

    This inquiry is in relation to internal combustion engines. I am trying to figure out how to maximize the mass of air going into my engine. Because the more air that can get into the cylinder, the more power the motor can make. Now I've been researching Bernoulli's Principle and as I understand...
  39. R

    Thermal Efficiency and Heat Extraction in Heat Engines: Figure Analysis

    1. What is the thermal efficiency for the heat engine shown in the figure? What is the heat extracted from the hot reservoir for the heat engine shown in the figure?t Figure shown here: 2.Wout = 1/2 B*H Also, Qc=Qh-Wout, efficiency: Wout/Qh 3. Wout = .5 * 200KPA*...
  40. C

    Can Delaval Valves Reduce Diesel Engine Air Cooling?

    the diesel cooling engines as produced by deutz have huge fans to deliver substantial amounts of air to the engine. they draw a lot of power from the engine. is it possible to use a mesh of delaval valves like a radiator that drops the temperature of passing air, thus, reducing the amount of air...
  41. J

    Entropy: steam engines and fridges

    A steam engine stove produces, say, 10 units of warmth, the second law states that not all warmth can be converted into work, so 8 units are converted into orderly energy, work, and 2 units aren't converted. Why did the entropy increase, since 10 units of warmth is more chaotic than 2? A...
  42. W

    Why Aircraft with Jet Engines Form Cloud Trails

    At higher altitudes in the atmosphere, why do aircrafts (particularly fighter aircrafts) with jet engines leaves some kind of white cloud trailing behind? It doesn't disappear for a reasonable amount of time. What is this? Thanks!
  43. C

    Lubrication in toroidal engines

    how do toroidal engines get lubricated?
  44. T

    How does a double acting steam engine work?

    hello i'm a first year student of mech eng...although its embarassing to admit, but i actually do not understand how a double acting steam engine functions. more specifically, i don't understand the inner-mechanism of the return-stroke. how does the piston come back to the top dead centre? is...
  45. D

    Circular Engines: Combustion and Automobiles

    Is there any circular engine (or any engine in general) which exhibits almost full time combustion? Leave alone turbine engines...that's too much of a hassle when implemented on automobiles (or is it?). Nope...no propulsion systems (like ramjet).
  46. R

    Engine vs Motor Capacity: Find the Right Match for Your Genset

    I was just thinking about replacing an engine with a motor in my genset but can't find the right match. It would be really great if someone can shed some light on the rationale btw. the two. How's the engines capacity rated and which motor capacity would be equivalent to a particular engine...
  47. Spinnor

    Thermodynamic efficiency of small diesel engines.

    Could a 10 HP diesel engine be made as fuel efficient as say a 100 HP diesel engine, that is (work done/fuel used). Does thermodynamics prevent a smaller engine from being more efficient? Thank you for your time.
  48. G

    How does bore/stroke and displacement volume affect an IC engine's power output?

    I am sure someone wrote with great detail on the subject, but i just can't seem to find it in the forums... I want to know about the parameters influencing the performance of an IC engine...obviously, not all parameters, but those we can conviently control specifically...how is bore/stroke...
  49. C

    Max Efficiency of a Carnot Engine vs Other Engines

    quick question, is the difference between a carnot engine to an engine is that the engines eff is less than or equal 1-(cold temp / hot temp), and the carnot is the max of this which is just equal 1-(cold temp / hot temp)?
  50. Topher925

    Why is methanol used in race engines?

    The enthalpy of formation of methanol (-22.7 KJ/g) is about half that of octane (-47.8 KJ/g). But methanol allows an ICE engine to achieve much greater specific powers than a comparable gasoline engine. My RC heli runs on methanol and will outperform any gas powered heli. But why is this? I...
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