What is Engine: Definition and 999 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. M

    Reverse Carnot Engine (Heat Pump)

    Homework Statement A house is heated by means of a carnot engine operating in reverse (Heat Pump). The outside Temperature (Tc) is 270k, and the required inside temperature (Th) is 300k. If heating the house to this temperature normally requires 10kW of electrical heating, how much power is...
  2. S

    Free piston engine modification

    I think that we may try to simplify free piston engine and it may look just like hollow cylinder made of very heat resistant material in which big cylindrical permanent magnet is moving back and forth horizontaly.The most heat resistant magnets could withstand temperatures up to 800°C (curie...
  3. R

    Low Cost Clay/Ceramic Steam Engine

    I am trying to design a low cost solar/steam engine for deployment where clean water and electricity are scarce. The prototyping I am currently doing is being done using plywood and a CNC router (mainly because that is what I have at my disposal). This will almost certainty not work as an end...
  4. C

    Internal-Combustion Engine Prototypes Ranking Task?

    Homework Statement Rank these engines on the basis of their designed power output and their thermal efficiency. 1) Qin = 3000 J, Qout = 1500 J, f=150 Hz. 2) Qin = 4000 J, Qout = 3000 J, f=50 Hz. 3) Qin = 1000 J, Qout = 200 J, f=200 Hz. 4) Qin = 2000 J, Qout = 500 J, f=50 Hz. 5) Qin...
  5. A

    Can a Split Cycle HCCI Engine with External Compression Work?

    Just wondering if an idea I've had for a few years would actually work. If I had an engine where compression took place externally and the engine was only used for combustion for example. This engine would be direct injected. The fuel would be injected a very high pressures (common rail)...
  6. Ivan Seeking

    What caused the recent engine problems on Qantas planes?

    http://www.google.com/hostednews/canadianpress/article/ALeqM5glnWkF4OYX0NZkxYhONr04DXvNOQ?docId=5045790 Two in two days? That seems unlikely.
  7. D

    What is the power output of the heat engine?

    Homework Statement The hot reservoir of a heat engine is steam at 100^ C while the cold reservoir is ice at 0 C. In 1.3 hr of operation, 11 kg of steam condenses and 52 kg of ice melts. Homework Equations I think power output is W=Qin-Qout The Attempt at a Solution I believe the...
  8. wolram

    A380 engine blow up Grounding News

    Trying to get a link that works. http://news.google.com/?hl=en-GB Qantas grounds A380s after engine blast The Australian - Steve Creedy, Peter Alford - ‎1 hour ago‎ Firefighters surround the Qantas superjumbo after it made an emergency landing at Changi airport in Singapore following an...
  9. Q

    What is it exactly about an explosion that pushes the piston in an engine?

    What are all the given aspects of this? I understand how the reaction happens, but what about it pushes the piston.
  10. G

    How can I build a DIY AC motor dyno for small engine development?

    Here's what the plan is I need a dyno for a new engine development program. small displacement engines, 50cc some day up to 200cc+. I need comparative data engine to engine, tuning, proto components, etc.. this is all diy budget stuff please keep this in mind. I come from automotive and race...
  11. F

    Determine the power of the jet engine of an airplane

    Homework Statement The jet engine of an airplane takes in 130 kg of air per second, which is burned with 4.3 kg of fuel per second. The burned gases leave the plane at a speed of 600 m/s (relative to the plane). If the plane is traveling 260 m/s, determine the power (hp) delivered...
  12. N

    Finding required thrust power for jet engine aircraft.

    Homework Statement I need to find required thrust power for lockeed s3a. I know Thrust=Drag in horizontal flight. For take off, need to use the take off angle, split the Weight (G) into 2 components using the takeoff angle... Same for landing. Given: G=19278kg ---> 19278*9.81=189,1kN...
  13. U

    Heat radiated from an diesel Engine

    Can anybody help me how to calculate the quantity of heat radiated from an diesl engine. any formula based on BHP? what are the assumptions that i need to make? what are the factors that i need to consider whilem calculating the heat radiated from an diesel engine
  14. X

    Developing a game that requires a physics engine with little knowledge

    Hello, This is my first post and if anyone can direct me to any links that would help I would appreciate it, but I'm having trouble understanding this on my own. I am developing a game with a physics engine and the scope I have in mind would require these calculations. I understand some of...
  15. A

    MATLAB Mathematical engine modeling (FHM) on Matlab

    I am trying to replicate a JAVA based applet on MATLAB. Applet can be seen http://www.engr.colostate.edu/~allan/thermo/page6/EngineParm1/engine.html" . The theory behind the functions of the applet is http://www.engr.colostate.edu/~allan/thermo/page6/page6.html" . It is actually a finite...
  16. G

    Pressure evolution in an engine intake manifold (thermodynamics)

    Hi, I am using a model that estimates pressure (P) in an intake manifold. I think there is a mistake in its equations but I cannot find it. To simplify the problem we can make the following assumptions: - Only air fills the manifold: air comes into the manifold through the throttle (mass...
  17. A

    Calculating temperatures of reservoirs in Carnot engine

    Homework Statement An ideal monatomic gas is the working substance of a Carnot engine. During the isothermal expansion, the volume doubles. The ratio of the final volume to the initial volume in the adiabatic expansion is 5.7. The work output of the engine is 9x10^{5}J in each cycle. Compute...
  18. S

    Can IC engine efficiency can be increased beyond 60% ?

    I found following claim from an inventor: “The limit of IC engine efficiency cannot be normally exceeded due to facts entropy cannot be decreased and 2nd law of thermodynamics (heat cannot flow from cold to hot body). Injecting water in the beginning of expansion stroke can overcome these...
  19. N

    How Does a Rocket Engine Maintain Constant Thrust While Power Increases?

    ok here's the problem. i really need on this. its not a calculation but more of an explanation. Consider a rocket engine. It delivers a constant thrust, which is the force exerted on the rocket by the expanding exhaust gases from the burning fuel.This typically is true in real life:both the...
  20. M

    Building a Jet Engine - Step by Step Guide

    Hi guys... we are currently interested -in our clip of aerospace engineering in my uni.- to build a complete jet engine ... unfortunately.. we have not yet found any detailed explanation to each step in doing so .. if you have any link or uploaded book or even you remember some manuals...
  21. L

    Projectile Motion airplane engine question

    1. You're in an airplane that flies horizontally with speed 1000 km/h (280 m/s) when an engine falls off. Neglecting air resistance, assume it takes 30 s for the engine to hit the ground. a. Show that the airplane is 4.0 km high. b. Show that the horizontal distance that the aircraft...
  22. G

    What is purpose and diffrence between FADEC and Electronic ENgine COntrol ?

    Can anyone please explain me what is difference between Full Authority Digital Engine Control and ELectronic engine control in an aircraft gas turbine Engine ? What all parameters are controlled in EEC and FADEC ? What is the main difference ?
  23. G

    Why air is compressed in Gas turbine engine ?

    i understood brayton cycle etc.. but why is air compressed in the GT engine ? iS is anything related related to following reasons ? 1. FOr better combustion of fuel, if so why ? 2 IS it to increase the temperature of air, if so why ? 3 any other reason
  24. S

    Can locomotive engine fenders be modified to prevent human and animal accidents?

    Hi Engineering guys, why you can't think about modifying the locomotive engine fender to push away human beings and animals from track. You know, each day there are hunderds of human beings are getting trapped under the wheels of locomotives. Can you guys think about modifying the fender -...
  25. P

    What types of bearings are used in a 2-stroke engine for model aircraft?

    I was taking apart a 2-stroke engine for a model aircraft and I'm a little confused about the types of bearings used for the connecting rod and crankshaft. So far, I know of the journal, needle, tapered roller, ball, and angular contact ball bearings. Does the connecting rod use a journal...
  26. smokingwheels

    My internal combustion engine is more efficent than 30%

    I have an spark ignited 4 cylinder 2000 cc engine in a wagon and I think its 50% thermally efficient at idle due to the mods I have done on the intake manifold. My engine uses (mesured on video) roughly 9.807 cc/min at approx 750 rpm and the only reference I have come across is a similar...
  27. K

    If i build a carnot engine in the real world, is its efficiney smaller than 1-t2/t1?

    I think it is due to friction and the carnot efficiency is derived in a reversible cycle. Also,can i build just a little bit irreversible but still carnot? But if irreversible how can i draw the graph? Still smooth line?
  28. M

    Striling Engine (manufacturing project) ideas welcome

    hey guys, We have a design project where we are supposed to design something cool to machine and later auction it off. My group has already come up with a plan to build a small stirling engine. I've been thinking if there could be anything we can add on to it, like a useful/fun addon...
  29. J

    How Does Changing Temperatures Affect Carnot Engine Efficiency?

    Homework Statement A Carnot heat engine operates between temperatures Th and Tc. (a) If Th = 515 K and Tc = 363 K, what is the efficiency of the engine? 0.30 Your answer is correct. (b) What is the change in its efficiency for each degree of increase in Th above 515 K? ? K-1 (c) What...
  30. Drakkith

    Building a Stirling Engine at Home

    Hello all. I've been wanting to build a Stirling engine at home out of parts that i could easily afford/scrounge up. Not one of those small ones that you hold in your hand, but one that could generate some real work. Enough to run a small generator maybe. The problem is that i have absolutely no...
  31. N

    Contradiction/breach 2nd law? Simply with carnot engine + negative temperature

    Hello, For a reversible heat engine between temperatures T_1 and T_2, the ratio of heat going in and out the engine is \frac{Q_1}{Q_2} = \frac{T_1}{T_2} (second law). Say T_1 = 200 K and T_2 = 273 K, then heat goes from 2 to 1 and as we can see, the ratio of heat that goes in the engine is...
  32. N

    Is the MY-T Engine a Real High Efficiency Diesel Engine?

    one problem, the website is down, and has been for quite some time now. lots of info on the site great candidate for a high efficiency diesel engine.
  33. K

    Seeking Info on Plasma Propulsion Engine Design

    I wanted to ask about plasma propulsion engine. Plasma can be made by using radio waves. How this part of device looks like?(I know something, like an antenna, is used) I searched the net, but I didn't find anything. Thanks in advance. P.S Please explain as simple as you can
  34. J

    Definition of an engine operating between two temperatures

    In several textbooks I've read that treat classical thermodynamics, there is a theorem due to Carnot that is commonly stated: "No engine operating between two given temperatures is more efficient than a Carnot engine" (incidentally, this is the statement in Huang's book) In these same...
  35. S

    Calculating Weight Savings of Aluminum Engine vs Cast Iron

    I've never taken physics, and I'm not even sure this is physics. :S On the hint it mentions, think of freshmen physics, but I honestly have no clue. Could someone help me out on how to even start this problem? Estimate the weight savings if a typical automobile engine (100 kg) is made of...
  36. I

    Maximum altitude of a rocket engine

    Homework Statement A rocket is launched at an angle of 53 above the horizontal with an initial speed of 100 m/s. It moves along its initial line of motion with an acceleration of 30 m/s^2 for 3 s. A this time its engines fail and the rocket proceeds to move as a free body. a. Find maximum...
  37. T

    Ramjet Rocket engine hybrid?

    I wanted to get some opinions on this, I am serious considering designing a ramjet rocket hybrid engine for my 3rd year mechanical engineering degree project and have started doing the research to see exactly how much work it entails I still can't quite decide... is this a realistic project? (my...
  38. S

    Powdered Graphite in engine oil

    From a chemical point of view, what are some of your thoughts about powdered graphite in engine oil? I think it would work very well because it would suspend particles between the graphene sheets.
  39. J

    What are the forces acting on a jet engine when encountering turbulence?

    Homework Statement A 1600kg jet engine is fastened to the fuselage of a passenger jet by just three bolts (this is the usual practice). Assume that each bolt supports one-third of the load. (b) During flight, the plane encounters turbulence, which suddenly imparts an upward vertical...
  40. G

    Flywheel Energy Storage and small engine

    I posted this on another section, but got no replies in three days...so thought maybe I'd had posted in the wrong section...apologies. I have an idea pertaining to energy storage in flywheels, something like they do in the KERS, and need assistance here... Ok, my idea involves using a...
  41. M

    Finding the Exhaust Temperature of a Carnot Engine

    Homework Statement A Carnot engine performs work at the rate of 360 kW while using 720 kcal of heat per second.If the temperature of the heat source is 650 C, at what temperature is the waste heat exhausted? Homework Equations because Th,Qh,and W are given so i going to use this formula...
  42. A

    Calculation of work done by/on engine

    Homework Statement During the working cycle of an engine, the heat transferred out of the system was 200kj/kg of working fluid. The internal energy also decreased by 300kj/kg of working fluid. find teh work done and state whether it is work done on the engine or by the engine. Homework...
  43. R

    Building a Solar-Powered Stirling Engine

    Hi Guys I m trying to make a Stirling engine power by solar heat. Somewhere I found out that the solar flux available on Earth is abt 1350watts/m2 Is this heat energy only or "heat & light " combined?? I m trying to find out if my soar engine will be better than traditional solar...
  44. M

    Implosion Engine - What is it?

    what is an implosion engine?
  45. S

    How do I calculate energy extraction in a heat engine?

    I have a qualitative understanding of a heat engine; that being that when heat moves through a heat engine from a source to a sink, an amount of energy that passes through the heat engine will be absorbed, until no heat gradient exists between the source and the sink The attachment is a...
  46. V

    Thermodynamic cycle of jet engine

    How to choose thermodynamic cycle for designing new jet engine? While designing new jet engine what parameters are important for choosing thermodynamic cycle? what other parameters are important for jet engine designing?
  47. S

    Nutating disk engine perspectives

    Recently there was information that military is developing a nutating disk engine http://en.wikipedia.org/wiki/Nutating_disc_engine" which, as they hope, will have higher power density, than reciprocating engine.Also some people say,that this is low friction design. Does anyone know what is...
  48. R

    Electric Motor and Gas Engine Horsepower Equivalency

    Is there a way to figure out the horsepower of an electric motor if you know the horsepower of a gas engine. For example: If the torque-to-horsepower equation goes as follows: [(Torque x Engine speed) / 5,252 = Horsepower] and I know that a 161cc gas engine has a Gross Torque of 7.00 ft-lbs...
  49. H

    Using search engine logarithmic scales

    Hi there, I have a problem for work that is stirring up lots of memories of University Math courses, and I need help! I work in search engine optimization, and search engines use logarithmic scales to value pages and websites. I'm using a tool that mimics those scales and assigns a number...
  50. C

    Could Hybrid Vehicles That Use An Engine to Power an Electric Motor Be Created?

    So with most of the hybrid vehicles around, they use a conventional engine and transmission with an electric motor to take over at certain points, and the engine recharges the electric motor. But could a hybrid be made that uses say an ordianry gasoline or diesel engine that directly powers an...
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