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. T

    Engine Modification Help: Automotive Technician Q&A

    Hi, I'm an automotive technician with a question on engine oil flow following a performance modification. Can you folks help me with that? Thank you, Alex
  2. EL_bob

    Magnetic assisted rocket engine

    Hello everybody! I have been thinking about something for a while now. I would like to make a magnetic nozzle for a rocket engine. Basically, I would like to ionize the hot and high pressure gaz in the combustion chamber and then use a strong magnetic field to adjust the nozzle throat...
  3. T

    Fuel with Static Air in a Jet engine

    Good evening, Today's planes' need bleed air to start. Above a certain speed, igniters fire up and we inject fuel inside the combustor chamber. Why do we need to have the engine running to inject fuel (around 20%N2)? Can we simply not inject fuel with static air (i.e. when engine is not...
  4. Pull and Twist

    Calculating work of Otto cycle stages - Thermodynamics.

    One big coincidence of thermodynamics is that automobiles are usually powered by an Otto cycle This cycle consists of an adiabatic compression (the cylinder compresses), isochoric compression (the fuel ignites, increasing the temperature in too short a time for the piston to move), adiabatic...
  5. S

    Changing my wood chipper's engine

    Hello everyone I have a wood chipper as shown in photos attached to this message called 'Morbark1.jpg' and 'Morbark5.jpg'. The engine on it as standard (Kohler Command CH25s 25hp) is too much hassle, time and money to fix and repair. My question is I wish to attach another engine onto the...
  6. P

    Automotive How Can I Optimize Airflow Across Different RPMs for My Motorcycle Engine Build?

    Ok so here it goes, I have a motorbike,and as I am a learning engineer I want to build a second engine for a few reasons, firstly I want to go faster secondly I want to do all the work myself to learn, thirdly I want to become a better engineer and want to do lots of paper work to learn and see...
  7. Kara386

    How far will the ship travel after the engine stops?

    Homework Statement A ship's engine supplies power of 85MW, which propels the ship of mass 5.3×106 kg across the sea at its top speed of 11##ms^{−1}##. The frictional force exerted on the ship by the sea is directly proportional to its speed. If it starts at top speed and then travels in a...
  8. TMT

    Overall efficiency of cascaded reverse Carnot engine & a Rankine turbine

    Assuming a reverse Carnot engine (Heat Pump Achieve 353K after compression and 253K after evaporation) is cascaded to Rankine turbine such that heat rejection to a steam boiler and heat is collected from a thermally isolated compartment first (used as condensation by cooling) then from ambient...
  9. grandpa2390

    Calculating the Efficiency of a Heat engine

    Homework Statement I am trying to calculate the efficiency of this heat engine that has two step. an adiabatic compression, followed by a linear expansion back to the original point. I keep getting an efficiency of 1, which I know can't be right... Homework Equations ##e = \frac{W}{Q_H}## The...
  10. E

    Temperature in a Carnot heat engine

    Homework Statement A Carnot heat engine takes 95 cycles to lift a 10 kg. mass a height of 11 m . The engine exhausts 14 J of heat per cycle to a cold reservoir at 0∘C. What is the temperature of the hot reservoir? Homework Equations η=1-(Tc/Th)=W/Qh The Attempt at a Solution I've tried...
  11. Jarro

    Stirling engine against solar panels

    Hello, Since childhood, I have been wondering why it is not possible to make miniature electric motors with pistons and gas container covered with a very dark (meaning high absorption coefficient over a wide spectral width) material that would translate the energy of sunlight directly into...
  12. G

    Error in this depiction of a Stirling engine?

    Hi. In my (German) physics lecture notes, I found this depiction of a Stirling engine: According to the text, it should be A: isothermal expansion B: isochoric cooling C: isothermal compression D: isochoric heating This seems correct for the PV diagram, but strange in the illustration on the...
  13. E

    Effects of engine torque on engine to chassis mountings

    I'm currently working on a design for a go-kart-like vehicle which involves some calculations. The engine used is a motorcycle engine and it is mounted to the main chassis via steel rods. I would like to know how the engine torque (i have an estimated value of ~45Nm) will cause stress and...
  14. S

    Carnot Engine cycle on PV Diagram

    I posted this in the engineer / comp science thread, but I've had no one reply or help. I really could use some guidance and I don't know where else to post. Homework Statement I am tasked to create a PV Diagram of a Carnot Engine Cycle. I must find pressure, volume, Q, W, ΔU, and ΔS on all...
  15. S

    Plotting Carnot Engine Cycle on PV Diagram

    Homework Statement I am tasked to create a PV Diagram of a Carnot Engine Cycle. I must find pressure, volume, Q, W, ΔU, and ΔS on all four points. This is what has been given to me by my teacher: a to b : Isothermal b to c: Adiabatic c to d: Isothermal d to a: Adiabatic TC = 300 K TH = 1700 K...
  16. J

    What would an antimatter engine be like?

    Antimatter thrust engine would be somewhat like a chemical or nuclear thrust engine, but with the difference that the exhaust would be pure light, and the fuel would the lightest possible fuel currently known to theoretically exist. That is known, but what would it really be like, meaning like...
  17. JLD Co

    Automotive Effect of vibration on engine efficiency

    It has been stated in previous threads that engine inefficiencies are caused by: Pumping losses (induction and exhaust) Frictional losses (in bores, bearings, and ancilliaries) Thermal losses to exhaust, coolant (jacket, charge and oil), and surroundings Does engine vibration have an effect on...
  18. M

    Internal Combustion Engine question

    Just out of curiosity, as I am very amateur here, in ICE could mono-crystal Alumina replace aluminum and create a better engine? Aside from the high cost to manufacture. I know MC-Alumina has a higher density than Al but is considerably stronger. This would be fantastic, I would think for a...
  19. Jason Louison

    Automotive Formulas For Engine Cylinder Perssure

    Hi! I am a new member to this great Forum! I am so excited to be a part of this wonderful community. Anyway, as the title suggests, I am looking for a way to calculate the pressure in each cylinder of any Four Stroke Engine at any given crank angle of Cylinder One. I have been trying creating a...
  20. mastermechanic

    How to calculate the torque of an engine?

    Actually I have 2 questions. 1-) How do we calculate the torque that the engine generates? t=F.d so F= The force piston exerts on crank arm. and d= length of crank arm. Can we calculate like this or is it completely different? 2-)Torque values of a car in the technical information is the...
  21. J

    Rocket Engine: Centripetal Force to Vector thrust

    Hey guys, I'm new to the forum and I have a question that has stumped several of the professors at my school. My idea is to use an electric motor with a solid rocket engine on a thrust stand to spin the exit cone. The concept would make use of centripetal force to increase the pressure of...
  22. physea

    Automotive Why engine efficiency drops for light loads?

    It is known that automotive engine efficiency (ie. fuel efficiency) is maximum at a specific range of medium loads. If we go higher than this range, the efficiency drops. If we go lower than these loads, the efficiency drops as well. Do we know the reasons for that? I am particularly interested...
  23. danyull

    Efficient Heat Engine and Final Temperature Calculation

    Homework Statement Two identical bodies of constant heat capacity ##C_p## at temperatures ##T_1## and ##T_2## respectively are used as reservoirs for a heat engine. If the bodies remain at constant pressure, show that the amount of work obtainable is ##W = C_p (T_1 + T_2 − 2T_f)##, where...
  24. T

    Work done by a Carnot Engine. Melting ice

    Homework Statement The problem is that a Carnot contains Boiling water in the hot reservoir and ice water in the cold reservoir. Given that 0.0400kg of ice is melted in 5 minutes, what is the amount of work done by the engine. Homework Equations Qh/Qc=Th/Tc W=Qh-Qc W=(1-Tc/Th)Qs q=mHf...
  25. A

    Nitinol Engine Design: Exploring Efficiency and Power Harnessing Techniques

    So I'm starting to do some tests with nitinol (order about 5 feet of wire just to do some basic tests and get a feel for the material before I go any further). I've seen a few variations on different types of motors that are powered by nitinol and am wondering if they all have the same...
  26. Maximilian Popelier

    What is the force of a jet engine and how can I calculate it?

    Hi Does someone know realistic numbers that i can put in this equation so i can calculate the force? Ty maximilian Popelier
  27. R

    Hobby rocket engine experiments

    I've started making my own sugar-based hobby rocket engines and I want to work on creating a de Laval nozzle for the specific fuel type and configuration I'm using. I don't have the resources to measure things like chamber pressure and exhaust temperature, so I wanted to try and develop an...
  28. P

    Water spray to steam during compression in a hybrid diesel-steam engine

    I just have read about a new kind hybrid diesel-steam engine where water has been injected inside an internal combustion engine to improve efficiency. The basic principle behind the process is that water will soak up a large section of heat generated by burning the fuel and will turn into steam...
  29. A

    Carnot engine efficiency problem

    Homework Statement A Carnot engine absorbed 1.0 kJ of heat at 300 K, and exhausted 400 J of heat at the end of the cycle. What is the temperature at the end of the cycle? Homework Equations The efficiency of a Carnot engine is given by the formula Efficiency = 1 – Qc/Qh = 1 –...
  30. wolram

    Automotive What does it take to make an F1 GP engine

    At a cost of 1 million pounds per engine there must be some very exotic materials used.
  31. Maximilian Popelier

    Mechanical parts of a jet engine

    Hi guys I'm making a project about jet engine. I need to write 10 pages of the mechanical part of a jet engine. I already did it for physics. What can i talk about. I need formules en stuff in the 10 pages Ty for the help guys! Max
  32. Kernul

    What Forces Act on a Train Engine Going Around a Circular Curve?

    Homework Statement A train engine of mass ##m## is chugging its way around a circular curve of radius ##R## at a constant speed ##v##. Draw a free body/force diagram for the train engine showing all of the forces acting on it. Evaluate the total vector force acting on the engine as a function...
  33. S

    Work and heat transfer in internal combustion engine

    Homework Statement : [/B]At the beginning of the compression stroke of a two-cylinder internal combustion engine the air is at a pressure of 101.325 kPa. Compression redeuces the volume to 1/5 of its original volume, and the law of compression is given by PV^1.2 = const. If the bore and stroke...
  34. yecko

    What is the Thermal Efficiency of an Engine?

    Homework Statement http://i.imgur.com/SQ6jx94.png (sorry for the low resolution~ it's already the best i can make it~) Homework Equations U=Q+W the three variables of isobaric, isochoric, adiabatic process (can i save my effort from typing all of them out?) e=(Qh-Qc)/Qh The Attempt at a...
  35. F

    How to show that Carnot engine is more efficient?

    Homework Statement Consider an Ideal gas engine with the following cycle: i. Isobaric expansion (T1 -> Th) ii. adiabatic expansion (Th -> T2) iii. Isobaric compression (T2 -> T_L) iv. adiabatic compression (T_L -> T1) a. Find its efficiency b. When operated in two temperature, show that Carnot...
  36. Const@ntine

    Understanding Forces and Motion in a 3D Coordinate System

    Homework Statement A toy rocket engine is securely fastened to a large puck that can glide with negligible friction over a horizontal surface, taken as the xy plane. The 4.00-kg puck has a velocity of 3.00ˆi ms at one instant. Eight seconds later, its velocity is (8.00ˆi + 10.0ˆj) ms. Assuming...
  37. betty0202

    Solving Boat Motor Engine Equations w/ Integration

    Homework Statement turning on the engine of a motorboat (v0=0), K = constant force due to the engine drag force of the water D = -cv find v(t)=? Homework Equations integration f=ma, a=dv/dt The Attempt at a Solution [/B] D+K = MA K-cv = MA (A=dv/dt) K-cv=Mdv/dt Mdv=dt(K-cv) ? i want to do...
  38. onargaroberts

    Impact of the engine thermostat temperature setting on engine efficiency

    Will a four cycle, internal combustion engine have greater thermal efficiency with a relatively cool jacket water temperature, say 160 degrees F, or a relatively hot water jacket temperature, say 190 degrees F? These specific numbers are only important in as much as they are commonly available...
  39. bigfooted

    Engineering Aircraft engine design books from 1900-1920

    I'm interested in the knowledge that was available to aircraft engineers in the period 1900-1920. specifically the thermodynamics and mechanical engineering knowledge generally available, like in how much detail were the calculations on the performance, or the cooling of engines done, how...
  40. ChloeYip

    What is the difference between Otto engine and Carnot engine

    What is the key difference between Otto engine and Carnot engine? Other than it is reversible or not, it seems to me they are so similar. Thanks.
  41. B

    Carnot engine acting upon another Carnot engine

    Homework Statement Suppose an amount of power P_{\ell} is delivered to a load by a black box with potential difference V_T across it, driving current I through a single loop. If an amount of power P_b is applied to the black box, to sustain I at V_T, then the efficiency of this black box acting...
  42. Ugnius

    The internal combustion engine

    Homework Statement Hi , I'm struggling with new paragraph about internal engines. When four-stroke internal combustion engine spins crankshaft 100 times , piston does 300 ticks. How many cilinders does engine has? Homework Equations I don't know how to create equation to calculate that , i...
  43. caters

    Completely solar powered engine -- is my design good?

    The engine of a solar car I am designing(for my fictional stories but I would like a scientific point of view on this) is literally a DC circuit combined with mechanical force. First of all, there is a rechargeable battery. I would say it is about 24V fully charged. There are 2 wires coming off...
  44. TheBigDig

    Finding the energy dissipated per cycle in a Stirling Engine

    1.Recently, we performed an experiment to measure the efficiency of the Stirling Engine. The experimental method can be seen in the image provided. We have been asked to calculate the power dissipation PR and the energy dissipation per cycle WR as part of our lab report. The other variables...
  45. G

    Finding the distance traveled by a steamer

    Homework Statement A steamer starts from rest, the engine exerting a constant propelling force Mf, where M is the mass of the steamer. The resistance of the steamer is assumed to vary as the square of the speed. Show that the distance x traveled in time t is: x = (V^2 /f) ln cosh (f*t/V )...
  46. R

    Automotive Twin engine vs inline flywheel supercharger idea?

    Had this idea today in my garage when I was setting up timing marks on the crankshafts and flexplate,the front engines flexplate would not be spinning the transmission.The flexplate is 14 inch diameter could you weld a series of fan blades to the flywheel face, get a modified bellhousing create...
  47. R

    Automotive Standing mile race car twin engine heavy front end?

    got a twin ls1 standing mile car project I've been toying with for a while.My question is the engines have beeen fit in the engine bay with the rear motor having minimal setback to allow room for the front engine,the total weight for both engines is 760 lbs,half of that weight is ahead of the...
  48. oobgular

    Rocket engine operating in a vacuum

    Homework Statement So suppose there is a chemical rocket operating in the vacuum of space (assume it's a perfect vacuum). It generates a hot gas with a total enthalpy of h. What's the final speed of the rocket exhaust, in terms of h? Homework Equations The energy equation seems to be useful...
  49. R

    Automotive Coupling electric motor to gas engine in series

    Would it be possible to couple and electric motor to gas engine in series so both would increase the overall power.I currently building a twin engine car with two gas engines coupled together crank to crank like the old school twin dragsters.I would like to connect a large D.C. Motor in front of...
  50. wolram

    New rocket engine may enable trips to Mars

    https://www.sciencedaily.com/releases/2016/09/160929161628.htm Return trips to Mars without refueling could be a step closer, thanks to a unique new thruster technology.
Back
Top