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. D

    How can I build an aerospike rocket engine with a three-component fuel mixture?

    Ok so I'm no grad student asking for help on a research project. I'm a senior in high school that is totally burnt out when it comes to the daily grind. I think I found a project, that hopefully is possible, and that will take me oodles of time and feed my hunger for education without a stupid...
  2. Wellesley

    Thermodynamics - Carnot Engine

    Homework Statement A Carnot engine has 40 g of helium gas as its working substance. It operates between two reservoirs of temperatures T1 = 400°C and T2 = 60°C. The initial volume of the gas is V1 = 2.0 X 10-2 m3, the volume after isothermal expansion is V2 = 4.0 X 10-2 m3, and the volume...
  3. homology

    Carnot engine with finite reservoirs

    Homework Statement I'm trying to find the final temperature of a carnot engine with two finite thermal reservoirs. We're told that the heat capacities for both reservoirs are constant (and equal) and to regard the change in each reservoir's temperature during any 1 cycle as negligible...
  4. V

    Ideal Carnot Engine: Find Time & Power Output

    Homework Statement An ideal Carnot engine operates between a heat reservoir and a block of ice of mass M. An external energy source maintains the reservoir at a constant temperature T_{h}. At time t=0 the ice is at its melting point T_{0}, but it is insulated from everything except the...
  5. O

    Frequency of Siren Perceived at 50m After Fire Engine Passes

    Homework Statement Assume that the speed of sound in the air is V=343m/s. Use the generalized form of the Doppler equation to solve the following problem. You are standing 100m away from a long straight road while a fire engine passes by along the road. The fire engine is equipped with a...
  6. W

    Heat engine, how much power does it use in watts?

    [b]1.A heat engine is rejecting 200btu/h and 30% efficient, how much power does it use in watts? [b]2. QH=w+QC and power=energy/time (1kwh=3412btu) and a power diagram: QC= wasted heat, w=work QH l 30%l---->W l QC [b]3. 200btu/h(1kwh/3412btu)(1000w/1kw)=58.6watts...
  7. M

    Determining Mass of Moment of Inertia for Flywheel in IC Engine

    i have diagram of the turning moment in flywheel in internal combustion engine , i want to determine the mass of moment of inertia of the flywheel needed to keep speed fluctuation < or equal 1.5% at engine speed 560 rpm ? http://img534.imageshack.us/img534/1765/57306264.jpg
  8. K

    Ideal monatomic gas engine problem

    Homework Statement An ideal monatomic gas is confined to a cylindrical container having a movable, yet "snuggly-fitting," lid that slides up and down to accommodate changes in pressure and volume. The diagram shown below, outlines the steps in a heat cycle starting at position A and moving...
  9. S

    Problem related to power of engine and resistance

    Homework Statement A car of mass 500 kg has a maximum speed of 40 ms-1 on a level road with the engine of the car working at a constant power of 20 kW. The resistance to motion is proportional to the square of the speed. (i) find its acceleration when the speed is 20 ms-1 (ii) find the...
  10. W

    Calculate Heat Rejected by 200W Lamp in 1 Hour

    Given : QH=W+QC and Power= E/t or W/t A heat engine is attached to a 200W lamp. If we power the lamp for 1 hour and extract 700 btu from the heat source, how much heat is rejected? Attempt: 200w(3.412btu/1w) = 682.4 btu now, 700 btu-682.4 btu =17.6 btu rejected??
  11. V

    Efficieny of a diesel engine

    Homework Statement The diagram below shows the thermodynamic cycle of a diesel engine. The compression ratio is the ratio of maximum to minimum volume; r=\frac{V_{1}}{V_{2}}. In addition, the so-called cutoff ratio is defined by r_{c} = \frac{V_{3}}{V_{2}}. Find an expression for the...
  12. R

    Heat transfer inside engine combustion chamber

    Hi, I'm not sure if I've got this in the right section, but I'm hoping someone can point me in the right direction. I'm trying to create a model of what's actually happening during the combustion cycle in an engine and where the energy is going. As the intake valve closes and the piston...
  13. D

    Morse Test Results: Engine Indicated Power

    Morse test! A morse test is sued to determine the mechanical efficiency of a petrol engine. these are the results Torque (Nm) No plugs shorted 91 no1 shorted 63 no2 shorted...
  14. C

    Thermodynamic equation for combustion in a spark ignition engine

    if i have calorific value of mixture, volume at time of compression, bore diameter, can i know the pressure being exerted on the pistons due to the combustion?
  15. T

    Clarifying the Cooling Stages of a Carnot Engine

    Note this is more of a coursework question about the theory behind Carnot engines as opposed to an actual homework question. Homework Statement The Attempt at a Solution So I am reading the theory behind a Carnot Engine and I am a little confused about the cooling stages of the Carnot cycle...
  16. O

    Small wheel folding bike, which rc engine best for lightweight n performance ?

    I got a small 16inch folding bike weight 13kgs and managed to shed it down to 9kg and working in weight reduction further... eg using hollow shaft at the peddle and using clips at the axles and replacing to 14inch rims and redoing the frame in lighter stainless 201 - these are my next to-do...
  17. R

    Working Of Additional Engine In Freight Trains

    1. I have heard the argument that "the Effort ( Force ) required to move a certain mass by Pulling is greater than the Effort required to move the same mass by Pushing it". What is the truth regarding this statement and what causes the difference in the applied force to move the same...
  18. V

    Doubt: Is 3 Stroke Engine Possible?

    Is 3 stroke engine possible??if not why?
  19. R

    Understanding Torque Transmission in Engine Clutches

    Hi guys I read somewhere that "the actual torque transmitted from the engine to the clutch is the total engine torque subtacted by the amount of torque required to accelerate the inertia of rotating components of engine.i.e:" T(c) = T(e) - [ I(e) x \alpha(e) ] where T(c)=Torque at clutch...
  20. H

    Conversion of Internal Combustion Engine Vehicle to Hydrogen Fuel Cell Vehicle

    I’m from a group that is current working on the theory of a Hydrogen Economy. Our first area of development is the Hydrogen Highway. We are currently seeking help in the form of freelance / work for hire basically engineer(s) that could aid in design and calculations of internal combustion...
  21. N

    Exploring the Design and Functionality of Reciprocating Compressed Air Engines

    Hello, I am currently doing a project on reciprocating compressed air engine and would like to have explanations about the mechanical design - is it similar to a reciprocating air compressor or steam engine, that is, does it have a conventional piston-cylinder assembly, connecting rod...
  22. G

    Components of Fuel System for Single Cylinder Engine w/o Carb & Above Tank

    Hi, i am interested to know the major components of the fuel system of a car. I know, these are the major ones: Fuel Tank, Fuel Pump, Fuel Filter, Injector Valve, Return Lines but what i am interested is in the fuel system for (1) a single cylinder engine, (2) no carburetor (instead, i am...
  23. O

    Two piston or 4 piston engine

    suppose a bike which has 2 piston engine and other is 4 piston. which one is most powerful? thanks
  24. G

    How Much Coal Must Be Burned in a Steam Power Plant to Generate 900 MW?

    Homework Statement 18. (II) At a steam power plant, steam engines work in pairs, the heat output of the first one being the approximate ehat input of the second. Th eoperating temeprautres of the first are 680 degrees C and 430 degrees C, and of the second 415 degrees C and 280 degrees C...
  25. C

    How Should Pistons Be Timed in Differently Angled Cylinders?

    Im looking at designs for a engine, but I am giving myself a headache over something which is probably incredibly obvious. Ill explain it as simply as I can in text and I've drawn a (terrible) paint image to help explain it a bit better. There are two cylinders. One cylinder needs to have its...
  26. V

    How Much Energy Input Is Needed for an Engine to Perform 10.2 kJ of Work?

    Homework Statement A heat engine operating between 78.5oC and 204oC achieves 20.6% of the maximum possible efficiency. What energy input will enable the engine to perform 10.2 kJ of work? The only help I need with this is exactly what equation(s) to use. I would think thermal efficiency...
  27. B

    Been working on a new engine design

    So, I've been working on an engine design that has been tried already, and nobody has really got it to work the way i think that it should. The engine I'm working with is a Wankel Rotary Engine and what I'm trying to do is make a modern, high-efficiency, high power-output diesel out of it. I'm...
  28. M

    Engine Braking: Comparing Petrol vs External

    please explain engine braking? the definition i found was " braking effect caused by throttle position induced vacuum in petrol engines".In what way is this better than external braking?
  29. V

    What are the design considerations for a 5kW Stirling engine?

    Hey, I'm an electrical engineering student and I'm trying to design a solar dish which converts the heat from sunlight into electricity. I managed to make a small stirling engine with the results i got from google (The stirling engines made from coke cans). I was wondering how costly...
  30. D

    Power of a Jet Engine: 1.5 * 10^9 Nm/s

    A jet engine develops 1 * 10^5 n of thrust in moving the airplane forward at a speed of 900 km/h. What is the power developed by the engine? I thought I needed to convert 900 km/h to m/s, so I did and I got 15000 m/s. The only equation I see to use for this is: P = Fvcosθ When I...
  31. S

    Thermodynamics: Steam Powered Carnot Engine Question

    Homework Statement A steam engine has a cylinder 80cm in diameter with a piston that has a total travel length of 1.8m. Assume that there is no "dead space" between the cylinder head and the piston when the piston is farthest in the cylinder. Steam is piped into the cylinder head from an...
  32. S

    What is the best design for cooling vents on a Sukhoi radial engine?

    Advice needed please with the design of cooling vents, louvres on the cowling of a radial engine. Plane is a Sukhoi, as per vid links below, 76 inch span 37cc petrol engined radio control. Cooling will be from cutouts in the cowl approx 20 x 80 mm with a flat plate louvre at the leading edge...
  33. A

    Solving Heat Engine Problem: Power Output Calculation

    Homework Statement The hot reservoir of a heat engine is steam at 100 while the cold reservoir is ice at 0. In 1.3 of operation, 12 of steam condenses and 59 of ice melts. What is the power output of the heat engine? Homework Equations W=Q_h - Q_c n=W/Q_h=1 - (T_c/T_h) Q=ML...
  34. G

    Viability of Heat Pipe technology in Internal Combustion Engine Cooling

    Hi there, my first post on this forum and I hope its in the right place ! My question is this, in an exisitng air-cooled motorcycle engine what is the viability of using heat pipe technology to cool exhaust gas temperature? Using heat pipes to remove heat from exhaust valve areas to external...
  35. T

    What is the fastest speed ever recorded, achieved by an internal combustion engine?

    What is the fastest speed ever recorded, achieved by a internal combustion piston engine on a land vehicle, and not an aircraft/propeller? I know that some top-fuel dragsters can exceed 300 MPH.
  36. C

    How Does Gas Volume Change After Combustion in an Engine?

    Hi you all Seaching in internet, I have not found an answer to this: In a air-gasoline stechiometric mixture, what can be the volumen relationship between the unburned (intake gas) and final exhaust gases?. I guess temperature is important, but let's consider a normal working...
  37. C

    Calculating Tension in Couplings of 100T Engine & 400T Train

    Homework Statement Engine: 100 tonnes, with 1,000N frictional force Train: 400 tonnes, with 20,000N frictional force Speed = 80km/hour Engine is exerting a power of 4000kW Find the tension in the couplings between train and engine The Attempt at a Solution I'm not sure where to...
  38. T

    Cyclic variation of engine torque

    ! Cyclic variation of engine torque If the cylinders fire sequentially according to the fire order 1-2-4-3 What is the pattern of the cyclic variation of each cyclinder engine torque and the resultant engine torque?
  39. L

    Gas pressure in internal combustion gasoline engine

    can anyone please tell me what is the gas pressure which applies on piston head just after combustion in cylinder its very urgent and necessary for me to know this please help me
  40. J

    Using Solenoids to Create an Automobile Engine: Patents & Possibilities

    I once saw an engine study that uses solenoids in compensating engagements much like the internal combustion engine. It was a small contraption but it worked. It used 12v dc current. I am just wondering if the engine can produce enough electricity to recharge the battery it uses if an alternator...
  41. S

    Gas in a 748mL cylinder of a diesel engine has a pressure of 1.72 atm

    The gas in a 748mL cylinder of a diesel engine has a pressure of 1.72 atm at 306K. What will be the volume of the gas when the piston compresses it to 46.5 atm and 777K?
  42. A

    Pulsation damping in a heat engine

    Hi all, I have recently been shown a diagram of pressure versus piston position for a particular heat engine. The system is based on a Joule cycle and is designed to take a drive stroke at constant pressure. Now what I'm trying to understand is, the pressure appears to 'wobble' slightly...
  43. E

    Does the piston ever stop moving in a running engine?

    Does the piston ever "stop" moving in a running engine? well guys...does it?
  44. J

    Theromdoynamics-TV diagram & Heat Engine

    1. The pressure is constant at 1Mpa how come it goes up after touching saturation vapor line.?Shouldn't it remain constant throughout? Please look at the Tv diagram below: http://www.ent.ohiou.edu/~thermo/Intro/Chapt.1_6/ideal_gas/tv_ideal.gif 2. Why quasi-static equilibrium is necessary...
  45. P

    Gas engine running on Veggie oil -

    Before I get flamed for this, I am not running a gasoline engine directly with normal fuel oil or veg oil- I made a gasifier. My gasifier is lame at the moment, but is just for testing purposes. It consists of a small fuel reservoir, suspended several feet up, then it flows down through about...
  46. B

    Formula to calculate the engine inertia

    Dear All, Please help me about how to calculate the requirement inertia of flywheel when i changing from 1.8 m to 1.2 m diameter flywheel for the total system inertia. The mass for engine is 5200kg.
  47. L

    Efficiency of Carnot Engine Question

    Homework Statement This is from "Equilibrium Statistical Physics" by Plischke and Bergerson, problem 1.1: "Consider a Carnot engine working between reservoirs at temperatures T1 and T2. The working substance is an ideal gas obeying the equation of state [ PV=Nk_BT ], which may be taken to be...
  48. A

    Pulse Jet engine - A new design concept

    I`ve had a new idea in designing a pulse jet by adding a valve in it... According to my intuition and logically this increases the output many folds and I`ve given sufficient reasons for suggesting it. I have a powerpoint of my idea that I have made and I request any of you to please go through...
  49. S

    Efficiency with a combustion engine

    I've been trying to understand why fuel economy decreases when the engine gets into higher RPMs. That is, if you put the pedal to the metal and quickly accelerate to 40 MPH, your engine operates much less efficiently than if you slowly accelerated to 40 MPH. Here's where it seems the...
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