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.

View More On Wikipedia.org
Recent contents Top users
  1. C

    Stirling Engine School Project Help

    I need to generate electricity from this, how would I do so? I was thinking about placing magnets on the flywheel and using silver wiring as a conductor. This needs to power an RC cars electric motor so I can drive the thing and I have little to no experience with anything electrical. Any...
  2. schrodingerscat11

    Efficiency of Carnot engine that uses a paramagnetic substance

    Homework Statement Greetings! A Carnot engine uses a paramagnetic substance as its working substance. The equation of state is M = \frac{n D H}{T} where M is magnetization, H is the magnetic field, n is the number of moles, D is a constant determined by the type of substance, and...
  3. K

    Why do diesel engines produce less power than gasoline engines?

    Hello all; I have been thinking about this for some time and searching through the internet for it but couldn't get a satisfactory answer for it, so i decided to ask this to you. Here is my question: If diesel fuel has more energy in it than gasoline does and if diesel engines are more...
  4. marellasunny

    Gyroscopic effect in a horizontal axis IC engine

    My tutor says Henry Ford opted for a horizontal-bed IC engine for the Model-T as this would avoid having any gyroscopic effects(normally associated with a vertical oriented engine). My question is,how does it matter if the engine cylinders are oriented horizontally or vertically?since the...
  5. B

    Calculating Bore and Stroke for a CO2 or Air Powered Engine

    To give a little background I have machine tool training but not much other than what I have taught myself in general physics. Its a VERY interesting subject for me and I have thought about going back to college just to take a course or two relating to it. I come up with various ideas I would...
  6. M

    Inertia forces in an ic engine

    when they say the inertia forces in the engine,what does it refer to ? this is with respect to the fact that in a diesel engine the point of maximum pressure is at combustion as there are no sufficient inertia forces to cancel out load forces..
  7. 1

    Carnot Engine Question: Efficiency & Work/Heat Rejected

    Homework Statement A Carnot heat engine absorbs heat form a high-temp reservoir at 1200K and concerts some of it into useful work and rejects the rest to a low-temp reservoir at 400K. A) What is the efficiency of the engine? b) If the engine absorbs 2400J per cycle from the high-temp...
  8. M

    Is My Internal Combustion Engine Efficiency Too Low? A Table Analysis

    i am calculating the properties of an internal combustion engine, however, for efficiency i am getting a value of 0.2%.This seems too low to be correct. please see attached table of values and point out any figures that seem incorrect thanks
  9. K

    Modelling heat loss to cylinder walls in a piston engine.

    I am building a mathematical model of a piston engine which calculates the pressure and temperature of the cylinder gas every 1° of crank angle. I'm having some difficulty with the heat transfer to and from the cylinder wall (to when the Tg > Tw and from when Tg < Tw). I found the heat...
  10. K

    Shortest collision time that will leave engine block intact?

    Homework Statement In a crash test a solid concrete wall is used to test crashworthiness. A particular SUV weighs 338.183 kg and is accelerated to 33.3485 m/s before colliding head on with the barrier. What impulse must be applied is required to stop the SUV? This gives Impulse =...
  11. A

    How to find the maximal mechanical power output of a stearin engine?

    Homework Statement "How does the placement of the puncture hole of a stearin engine affect the power output of the system?" By a stearin engine, it just means an oscillating candle around a fixed point; a video can be viewed at . I have done all of the data collection by testing...
  12. M

    RPM Problem with Duke's Single-Cylinder Engine

    I am facing this RPM problem with my single-cylinder engine(Duke's) that I have used in my project.. Even though the ECU is programmed to allow RPM upto 12,000 revs but still engine can only reach 6,000 when the clutch is engaged...it can go near to 12,000 only while the clutch is disengaged...
  13. D

    How Is Engine Efficiency Calculated Using V1/V2 in Thermodynamic Cycles?

    Homework Statement Four thermodynamic processes A,B,C,D are shown in the picture. A and C are adiabatic processes. Pressure is held constant during B, and volume is constant during D. An engine run from A->B->C->D->... What is the efficiency of this engine (in terms of V1/V2)? Homework...
  14. R

    Brake Mean Effective Pressure (Bmep) SI Engine

    Dear all, Can Torque max. be used instead of Power max. in the bmep equation?-(as shown on attached pic) The name of the equation seems to suggest it is only for Brake Power but hopefully i am wrong. Also, when I do a calculation for bmep for max. Brake Power and max. Torque, the bmep...
  15. A

    High-hypersonic external scramjet aerospike engine

    Take a look at the PDF I attached to this thread. Note that this sketch represents the entire aircraft. Also the aircraft may be much longer than in the sketch Do you think it would work above Mach ten ? What about lower speeds and lower altitude ? Has someone designed the same engine before me ?
  16. H

    Proving that a heat engine cannot exceed the carnot efficiency

    In many textbooks, a proof is provided where the work output of a super-efficient heat engine is provided to a carnot refrigerator, with the net result that a spontaneous heat transfer occurs from the cold reservoir to a hot reservoir. Let's use some numbers, TH = 600 K and TL = 300 K, so...
  17. K

    Work done by a car engine up a slope

    Hello. I've searched the internet hard but couldn't find anything about this so i decided to ask this to physicsforums. If a car is up a slope with friction and it's stopping(balanced) by using the gas pedal, what is the energy consumed by the motor of the car? I know F.x is 0 in this...
  18. T

    What is the definition of Engine Load

    What is the definition of "Engine Load" A lot of things I have read make reference to engine load but it is not clear if there are different meanings. One definition seems to be that the engine load is the amount of air flowing through the engine as a percentage of the theoretical maximum...
  19. T

    Ignition Timing vs. Heat Distribution in the Engine

    Hello all, I am studying four stroke ICE engines (as a mechanic) and there is something I can't fully understand about the combustion process. It's repeatedly documented in books that retarding the ignition timing will reduce cylinder temperatures / avoid engine knock. Though less...
  20. H

    Does a Rocket Engine Exert Same Force Regardless of Velocity?

    This is a problem I have never really understood. If a rocket engine is fired in a vacuum, does it exert the same force regardless of its velocity? If so, I don't know how to get around the following issue. Say that the chemical energy stored in a particular rocket engine is 100 Joules (I am...
  21. E

    Solid Fuel Internal Combustion Engine

    Has anyone ever built an internal combustion engine which runs on solid fuel? A system would have to use waste heat or a mechanical friction device or whatever to heat the fuel and produce vapor which would be burnt in the cylinder (similar to the way coal gas was produced). Of course the vapor...
  22. B

    Geothermal heat pump or heat engine power requirements

    Homework Statement In winter, you like to keep your house interior at 21.0 degrees C. Your geothermal heating system, which was advertised as being reversible, draws thermal energy from an underground reservoir at 347 K. In a cold winter, with the average outdoor temperature being 0.0...
  23. S

    Can a car engine dipstick be magnetized

    Hi, Is it possible to permanently magnetize a car engine dipstick? If yes, what would be the easiest way to get it magnetized, such that it will be able to lift an (rusted steel) object which is about 10 grams or lighter.
  24. E

    How can Solar Thermal Rocket Engines revolutionize space exploration?

    Dear visionary inventors, megalomaniac engineers and audacious explorers, Chemical rocket engines aren't up to our desire to hop in the Solar system: go quickly to Mars, deviate Earth-threatening objects, and so many more missions. We need a higher ejection speed to save propellant mass, but...
  25. H

    Engine valve control: camshaft or electronic control

    I just watched a video by Koenigsegg engineers and came across this question. Why is camshaft the primary control of the engine valves? Using electronic controlled actuators would certainly benefit the engine in aspect of performance, but might increase the cost of production as well. People...
  26. fluidistic

    Carnot engine with a magnetic auxiliary system

    Homework Statement I would like some assistance to solve the following problem. A magnetic system satisfies Curie's law ##M=nDB/T##, has a specific heat capacity at constant magnetization ##C_M=\text{constant}##. It is used in a Carnot engine that operates between temperatures ##T_h## and...
  27. H

    What is the purpose of using two cylinders in a Moriya Stirling engine fan?

    Hi all:I am currently considering building a moriya stirling engine fan turbine. I would like to know if anyone here has built one. If so, is it possible for you to explain why they use 2 cylinders (power and displacer)? what is the principles of using two cylinders over this type ...
  28. MalachiK

    Boeing 747 Engine Power: Realistic or Not?

    Hi there I'm writing a problem sheet for a class that I teach and I'm trying to use as many real world examples as I can. I'm writing simple questions about the power output of engines that are moving vehicles at constant speeds. I've used cars and boats, but now I want to use aircraft...
  29. marellasunny

    Interpretation of an ideal engine torque,power curves

    Attached you will find the torque vs engine rpm and power vs engine rpm curves for an 'ideal engine' and also for a 'normal SI engine'. 1.(for the 1st ideal engine curve) Is it 'ideal' that the torque curve should decrease as the engine rpm increases? Why? Does this mean that 'ideally' in a...
  30. G

    Physics of a diesel engine revving up and slowing down

    Hi everyone. So I am trying to write a very simple engine simulator for a game, and I have a question about how diesel engines accelerate and decelerate when a machine is in neutral. I have found some videos of a machine at full throttle and then the throttle released, and the engines...
  31. R

    Mastering Physics: Heat Engine Problem

    The figure shows the cycle for a heat engine that uses a gas having gamma =1.25. The initial temperature is T1=300K, and this engine operates at 20 cycles per second. a.) What is the power output of the engine? b.) What is the engine's thermal efficiency? The link to this image is here...
  32. marellasunny

    Chemical equilibrium reaction for burned gases in engine

    I do not understand how equation(3) occurs.(taken from the book Internal Combustion Engines by John B.Heywood) $$ $$ Consider a reactive mixture of ideal gases. The reactant species M_a,M_b etc.and the product species M_l,M_m etc. are related by the general reaction whose stoichiometry is...
  33. M

    Work of Carnot Engine integral

    I'm curious how do you choose the u and v transformations here to be equal to the constants and why is the f(u,v)=1 for the area- because you are summing infinitesimal x's and y's? I see that the area in xy is difficult to integrate because the sides are curved. is the transformation proven...
  34. C

    Engine lubricant temperature reduction

    I need to reduce the lubricant temperature in a motorcycle engine.? I've been allotted this project in a motorcycle company in India in which I need to reduce the average temperature to which a lubricating oil gets heated up, in an engine for one of their models. Now I did see the flow path of...
  35. L

    Data of Engine PW4060 PW123D and PW127E

    Hello! My name is Luis Trindade and I am a Aeronautic Engineering student. I am doing a comparative study on aircraft performance, but I lack data on some of the aircraft. These data refer to the engines. Needed to know the fuel consumption in cruise and traction on the cruise of the...
  36. 1

    Please help - Efficiency of car engine question Unit test tomorrow

    Please help -- Efficiency of car engine question... Unit test tomorrow Homework Statement A car's engine is only 12% efficient at converting chemical energy in gasoline into mechanical energy. If it takes 18000 N of force to keep the car moving at a constant speed of 21 m/s, how much chemical...
  37. marellasunny

    Design of 4 stroke IC engine from few parameters (bmep, B.P, piston speed)

    (I have trouble in finding the stroke length and fuel flow rate) From Heywood,E2.11 You are designing a 4 stroke CI to provide a brake power of 300kW,Naturally aspirated at its max rated speed.Based on typical values for brake mean eff.pressure(bmep){700kPa to 900kPa} and max mean piston...
  38. Todee

    Java How to make a search engine by Java ?

    want some sites to teach me how to develop a simple web-based search engine that demonstrates the main features of a search engine (web crawling, indexing and ranking) and the interaction between them. Using Java :confused:
  39. F

    Could a jet engine be run on nuclear power?

    I know people have designed nuclear rocket engines, but is there any reason you couldn't have a nuclear thermal jet engine? Simply take a conventional jet and swap out the combustion area with a small reactor? Could the same idea work at higher speeds with a nuclear ramjet, or scramjet equivalent?
  40. R

    How is the torque curve of a gasoline engine different from a diesel?

    Hi, my lecturer has given us two graphs showing the general shapes of the max torque curves for both gasoline and diesel engines, and they clearly show that the diesel engine has a much flatter torque curve than the gasoline engine, but not explained why. Expected to find this information...
  41. F

    Engine specs for large saloon (sedan vehicle)

    Need some help with this question. I have given it loads of thought, but my assumptions are not getting through. Here it is: 1. Objective (a) To determine the power needed to give the chosen vehicle the required performance; to determine the bottom and intermediate gear ratios. (b)...
  42. N

    New Engine technology: no camshafts

    ten minute youtube video... http://www.youtube.com/watch?feature=player_embedded&v=Bch5B23_pu0 From Sweden...Claims 20% fuel efficiency improvement, even more power improvement. This is episode 7 of a 9 part series...have not seen the others... enjoy.
  43. C

    Mean molar mass after combustion in a combustion engine

    Homework Statement The problem is to calculate the mean molar mass of the reaktion below, which takes place in a combustion engine. C4H10 + z(0.79N2 + 0.21O2) → αH2O + βCO2 + γN2 where the molar masses for the different molecules/atoms are: MH2O = 18, MCO2 = 44, MN2 = 28, MO2 = 32, MC =...
  44. J

    Efficiency of engine taking diatomic ideal gas through cycles

    Homework Statement What is the thermal efficiency of an engine that operates by taking n moles of diatomic ideal gas through the cycle 1 -------> 2 -------> 3 -------> 4 ------> 1 shown in the figure ? http://s3.amazonaws.com/answer-board-image/2d50cb1e-1bc6-4325-acf6-fe1df4f0a7b5.jpeg...
  45. A

    Equation Questions for a gas powered engine driving a pulley system.

    I am building a prototype for an agricultural pulley system and I need help calculating how much horse power I need. The pulley system will need to drag a 400 lbs. object of a 45 degree incline for 150 feet. The static coefficient of friction is 0.1 and the kinetic friction is only 0.05...
  46. W

    Calculating Work and State Variables for an ideal Stirling Engine

    Homework Statement Consider the ideal Stirling cycle working between a maximum temperature Th and min temp Tc, and a minimum volume V1 and a maximum volume V2. Suppose that the working gas of the cycle is 0.1 mol of an ideal gas with cv = 5R/2. A) what are the heat flows to the cycle during...
  47. S

    Carnot heat engine - calculate work

    Using Carnot heat engine we connect two objects with the same mass m, specific heat capacities c. At the beginning the body 1 has temperature T_{1} and body 2 T_{2}. Calculate: a) How much mechanical work can this engine give? I tried like this, but i believe this is very wrong :(...
  48. D

    Carnot Engine Between Reservoirs with Varying Temperatures

    Homework Statement Two containers with fixed volume are each filled with n moles of a monatomic ideal gas with constant heat capacity. Initially, the volumes of gas are at temperatures T_1,i and T_2,i. What is the maximum amount of work that can be obtained by operating an engine between the...
  49. F

    Fixing 2-Stroke Engine Issues for C125R Honda Motor

    I am in the process of working on a 2 stroke motor that I am looking into converting to fuel injection. One thing in particular that I find with the 2 stroke is that is less efficient than than a 4 just because fuel mixture goes out the exhaust port while it is still open. Is there any ideas...
  50. S

    Recommendation for good book for IC Engine design

    Hey Everyone, I'm a mechanical engineering student and I was wondering if there was any good book regarding IC Engine design; which includes timing belt design, camshaft, crankshaft, rocker-arm, pump design etc.. a whole in one package that design engineers use for designing ic engines...
Back
Top