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. C

    What is the Relationship Between Power and Current in an Elevator's Engine?

    Homework Statement An elevator is running upwards at the constant speed v. The magnitude of opposing forces is F_o. The elevator's mass is m and the voltage is V Find the magnitude current in the elevator's engine. 2. The attempt at a solution I tried to solve this task by energy equations...
  2. R

    Heat Engine problem in Thermophysics

    Homework Statement Im working on the following problem and could need some help in answering them: Work is being produced from a cycle. In order to produce this work, energy is being taking from a high temperature sources at a ratio of 1000 kJ/kg and the extra energy is being deliver to a...
  3. Metals

    Boost Your Engine's Performance: Answers to Common Nitrous Oxide Questions

    Now I'm aware of how at around 300 degrees C N2O breaks apart, resulting in more oxygen in the cylinders. I'm also aware that N2O cools down the air fuel mixture when it evaporates, increasing density and resulting in more volumetric efficiency. What I don't get, is why not just take in more...
  4. adska

    Hydraulic Engine: Ball Spin, Stop & Why?

    What will happen with metal ball in the below picture? it will spin? if yes, when it will stop and why? I am not very faimiliar with physics, but I am sure that ball must spin :D http://www.cagof.com/Untitled.png
  5. S

    Better muffler for small engine?

    I have a 9 hp subaru engine that operates a soil mixer. I find it obnoxiously loud. From other reading the 'mufflers' on many small engines are little more than spark arresters. The location of the engine (about 6 feet off the ground, and the exhaust (on top) make me think that it should be...
  6. K

    Diesel Electric Locomotive formula

    What formulas do Diesel Electric Locomotive manufactures use when designing new Locomotives? Are there any good books on the subject? Locomotive meaning train engine. I want to understand freight engine designs not passenger. Thank you, Kevin
  7. F

    Design Your Own 50ci Engine: Balancing Crankshaft

    Hi, I am going to design my own 50 ci engine, straight 4 cylinder 2 stroke. I know nothing about how I should go about the crankshaft... Very few drawings so far, can anyone guide me on any formulas i should use to figure out what i need, based on piston weight, rod weight and size, etc...
  8. W

    Wankel/rotary engine efficiency

    I was just wondering how we can find out the efficiency of a rotary engine? Obvious, it is more efficient than a gasoline/diesel engine.For example the RX8 on 1.3 L in 2 rotors get 250 hp which is quite impressive for that capacity,also it works in 4 stroke,and the power to weight ratio is...
  9. P

    Calculating Otto Engine Clearance w/ Efficiency 46.4% & k=1.3

    Homework Statement What is the clearance of an ideal otto engine if the efficiency is 46.4% and k=1.3 Homework Equations efficiency = Worknet/Heat Added k=1.3 hot air T= 1900kThe Attempt at a Solution i don't know how to start
  10. J

    What is the Temperature of the Low Temperature Reservoir in a Carnot Engine?

    Homework Statement A Carnot engine moves a piston which applies 5N of force to a rotating disc by moving a piston 0.25cm for a total of 5W of power. If the high temperature reservoir is 100K, what must the temperature of the low temperature reservoir be? Homework Equations The efficiency of a...
  11. A

    Pressure generated from gasoline combustion

    how much pressure can be generated upon ignition of gasoline/air in an internal chamber at atmospheric pressure? I know that combustion engines can generate well over 1000 psi on the piston but this occurs when the air is compressed to begin with.
  12. T

    Will this be more efficient than the Sterling engine?

    Hi everyone,I am hoping to discuss the value of a design. The original idea was intended to receive the thermal energy from the exhaust from an internal combustion (IC) engine and produce additional power. The working principle is much like a Stirling engine except that instead of a regenerator...
  13. Chevreuil

    4 stroke engine exhaust fed to high air flow

    Hello, So say that I have a small four stroke engine that is designed to be kept static at ground level. I then take this engine and mount it to a small air plane, feeding the engine with either still air from inside the cabin (cargo) or the outside wind. The exhaust is fed out to the wind...
  14. S

    Does efficiency always depend on reversibility of the engine?

    I'm confused on the efficiency of a Thermal engine in the case it is reversible or not reversible, in particular where the ideal gas follows isochoric or isobaric processes. Infact during isochoric and isobaric processes $$Q_{isochoric}=n c_v \Delta T$$ $$Q_{isobaric}=n c_p \Delta T$$ So the...
  15. S

    Efficiency of engine when non-boundary work done is done?

    The thermal engine efficiency is defined as $$\eta = \frac{W_{\mathrm{produced}}}{Q_{\mathrm{absorbed}}}\tag{1}$$ A more general definition of efficiency (not only for thermal machines is) $$\eta = \frac{\mathrm{Work \, produced}}{\mathrm{Energy \, absorbed}}\tag{2}$$ But suppose that, in one...
  16. Joyal Babu

    On the possibility of making an engine with efficiency 1

    https://www.researchgate.net/post/Gibbs_free_energy_U-TS_PVIn_a_high_pressure_environment_when_PV_equals_TS_can_we_actually_use_the_entire_internal_energy_of_a_system_to_do_work?_iepl%5BviewId%5D=EMvZ8y3kBTyHiPzK6A8YVYvn&_iepl%5BsingleItemViewId%5D=erF86LeZ0BmbObFXKscz92Ib&_iepl%5BactivityId%5D=7...
  17. B

    AC Alternator Load Loss on Engine Performance

    I'm trying to determine the amount of load (power loss) a theoretical engine will suffer from an AC alternator, such as one you would find on an automobile engine, they produce something of 40 amps with 110 volts I believe? To be specific, I'm curious to know how much a theoretical engine would...
  18. H

    Automotive What is the formula for force in an engine?

    hi. i want to know how much force acts on every piston in an v8 engine and how much torque acts on the crankshaft . pls also tell me how much energy is created in an engine and how much of it is lost, say in friction and other factors. pls tell the force at start of engine in car and at...
  19. trigger701

    What moves the piston in a Carnot heat engine?

    Hi everyone, I have been looking at Carnot heat engines in a bid to better understand entropy, and I can't figure out how it actually does work. Why does the piston move? In some diagrams I have seen weights being removed from the piston, reducing the pressure at constant temperature and...
  20. O

    Can a Hybrid Lightning Jet Engine Outperform a Traditional Jet Engine?

    Does lightning heat air 5 times more the the suns surface? If so can a hybrid lightning jet engine work, as lightning heats up air, more then fuel can? Americas 5th gen jet fighter can travel 3* more then enemy jet's. That means it's a hybrid engine right? Compressed air heated sees the air...
  21. Z

    Automotive Vehicle and Engine Simulink Model Engine rpm calculation

    Hello Everyone, I am designing Simulink model for HIL testing. Basic concept: Input: Throttle angle ----> Injection timing from that I have calculated requested torque (% of max torque)(chekced and correct) Real torque follows requested torque with delay. (long list of conditions depending on...
  22. Firasf1dream

    Effective Compression Ratio Definition?

    hello everyone, i would like please to know what is Effective Compression Ratio for an RC 2stroke Engine that i have ? the value in the info is 9.7, so i need to know the meaning and what values are the best ? what is the range ?
  23. F

    Automotive Engine in-cylinder pressure validation

    Hi all, I’m currently investigating the engine in-cylinder pressure by simulation and experimental method. All inputs parameters in the simulation were exactly follow the engine technical specification (engine geometry, compression ratio, fuel injection parameters, initial pressure and...
  24. Firasf1dream

    Need help in calculating Engine Air Flow and Specs Explanation

    hello everyone, i hope you're doing well, i am new to this forum so i am not sure if this is the right place for my question what i am doing is trying to calculate the air flow needed for intake of an RC engine Zenoah G320RC in the attachment files, it's a pdf for the info about the Standard...
  25. wolram

    Explaining the Hyperloop Engine

    https://www.sciencedaily.com/videos/d5be126450ab9c4b5c94a7455f267d0a.htm The video does not say how this hyperloop (engine) works can anyone explain?
  26. Willfrid Somogyi

    Heat Extracted and Delivered to Reservoirs in a Heat Engine

    NO TEMPLATE---MISPLACED HOMEWORK So it seems like a pretty simple question, and in all likelihood it is, but my lecturer somehow managed to miss this bit in his lecture notes. A heat engine operates between 500K and 300K with 20% of the efficiency of Carnot engine operating between the same...
  27. A

    Thrust angle calculation for off-centerline airplane engine

    This isn't for any particular project or assignment, but I've tried solving this in the past and haven't figured it out. Say you have an RC seaplane, like the one pictured, with the engine mounted well above and aft the CG. You're going to need to angle it down a little to counteract the...
  28. P

    How do Search Engine Optimizers work?

    I know a bunch of people who have their own website or blog, including myself. When you search some of the sites’ names, they pop up immediately as the very first link and, for other ones, it just never pops up. I’ve tried to read about this, but I find it hard to understand. How does this work...
  29. jmalitz

    Liquid Fueled Engine: A New Perspective

    I know that this has been talked about already, but from the responses, I feel the topic was not addressed to the fullest, but as we know a Jet engine is subject to the amount of O2, so i was looking at a earlier post about this topic. within the replies to that topic the rocket engine was...
  30. J

    Calculating wheel torque from engine torque

    Im currently writing a code to find the optimum rpm points to shift gears to maximize acceleration. Thus far I've found the shift points and the rpm's after an upshift, meaning I have my bounds on my rpm vs torque curve. For simplicity's sake I'm assuming and increase of 1000 rpm to take 1...
  31. DevonZA

    Power output/input, energy input, efficiency of engine & generator

    Homework Statement Homework Equations P=2piNT/60 P=I^2R Pin=Pout/efficieny E=P/t The Attempt at a Solution 2.1 P=I^2R = (5)^2x48 = 1200W 2.2 Pin=Pout/efficiency = 1200/0.86 = 1395.35W 2.3 P=2piNT/60 *3100.78=2pi(500)T/60...
  32. anj

    Automotive Working Back from Wheel Torque to Engine Torque

    Hello All, Is it possible to work back from drive torque at wheel to engine torque? Can it be described with basic equations and is the calculation same between all wheel drive and front wheel drive? Thanks Anj,
  33. K

    Work done by a 20% efficient heat engine

    I had an exam last week and I just got it back today. On the exam was a question that I got wrong even though his wording was terrible (he's from India) and I feel that it was not clearly expressed what he was saying. The question is: "A heat engine is 20% efficient. If it absorbs 500 J of heat...
  34. S

    Automotive Calculating engine parameters from power requirement

    Hi, I've defined engine power requirements based on driving dynamics, but am not sure how to extend this to engine parameters. From design requirements, I've fixed my gear ratios, and hence can determine how much power and torque is required from the engine at a particular speed. I want to then...
  35. F

    Internal combustion engine calculation questions

    < Mentor Note -- Poster has been reminded to use the Homework Help Template and show their work on schoolwork problems > Hello everyone I have some questions on engine calculations that I need help in please. 1) A reciprocating internal combustion engine operates on a 4 stroke cycle. If the...
  36. Y

    I calculating the heat exhausted from an engine.

    Homework Statement A 112 hp car engine operates at 11% efficiency. Assume the engine's water temperature of 85°C is its cold-temperature (exhaust) reservoir and 445°C is its thermal "intake" temperature (the temperature of the exploding gas-air mixture). (a) What is the ratio of its efficiency...
  37. devecseri

    Automotive Car Question Acceleration vs. Engine Life

    What's going to let an engine last longer: 1) Accelerating quickly to just above desired speed and coasting until speed drops 2) Holding engine at a more constant lower rpm to achieve that desired speed I know to some extent 1) is better for fuel when the acceleration isn't too hard but...
  38. O

    Internal combustion engine, front PTO

    Internal engines got a flywheel connected to the crankshaft on one side, and on the other there is a wheel that drive all the engine accessories with a belt. If the main power output would be taken from the "belt" wheel and not the flywheel, would I receive the same power output? And if no, is...
  39. L

    Why does heat engine need to do negative work to surround?

    Every thermodynamics cycle needs to do negative work to the environment, which lower its total positive work. For example, in Carnot cycle, the most efficiency possible: 1/ Engine receives heat from hot reservoir, expands and do positive work to surround 2/ Surround does work to engine...
  40. Futurestar33

    Electric engine for car vs Electric Engine for Drone

    Hello, I am trying to find out if there are any differences between how the Electric engine for car works vs how an Electric Engine for Drone works. I am sure the both consist of an Ignition coil, stator and rotor. However I have not been able to find the any schematics for a drones electric...
  41. scotty c

    HP to spin the fan in a VW type 1 air cooled engine?

    the vw type 1 engine comes with flaps that close when the engine is cold. i know the flow through the fan doesn't completely stop but for the sake off argument let's assume that is does. the fan is spinning but there is no flow. what power is required to maintain the pressure differential...
  42. S

    Calculation of torque of engine (mathematically)

    We have tried to convert a petrol engine into a compressed air engine back in our graduation project. At that time we only measured the RPM of engine using tachometer and pressure of compressed air using pressure gauge. Now, we need to know the power of wngine at those readings. As the setup is...
  43. H

    General-Electric GEnx turbofan engine picture label request

    Hi! I am a student who is passionate about engines and mechanics (although the major I'm pursuing is CS.I believe we must not inhibit our intellectual curiosity). The following link will take you to the picture of an uncovered General Electric Next Generation Turbofan engine used by the 787...
  44. S

    Price for the cheapest diesel engine?

    What is the price per kilowatt or hp for the simplest, cheapest diesel engine, such as ones used for powering irrigation pumps? Say one of 1/2 MW or 1 MW. S.A.
  45. A

    Efficiency of Irreversible Engine

    I have a small confusion that can an irreversible engine have greater efficiency than reversible engine if both have different source and sink temperatures?I know that under same conditions reversible engines are more efficient but what can be concluded under different conditions like both...
  46. RTE

    Increase a gas engine's RPM to drive a water pump

    Hello all, This is my first post, but I'm no stranger to skimming the boards. Always can find helpful stuff, but I'm stumped on this one. The situation is we have a Kohler 17 hp electric start gas engine horizontal shaft that max's out at 3600rpm. We are attaching a self-priming water transfer...
  47. B

    How to calculate PSI created in an internal combustion engine

    Hi, working on a project and I need some assistance due to my lack of education in mechanical engineering. With that said I will be as specific as possible. I need to figure out how much PSI is exerted on a piston during the power stroke in an external combustion emgine. I'm not sure how to...
  48. B

    Can't figure out solution -- Space probe with engine thrust vectors

    Homework Statement A space probe has two engines. Each generates the same amount of force when fired, and the directions of these forces can be independently adjusted. When the engines are fired simultaneously and each applies its force in the same direction, the probe, starting from rest...
  49. jdawg

    Find the thrust from the engine

    Homework Statement A static thrust stand is to be designed for testing a jet engine. The inlet conditions for the test are an inlet area of 1 {m2}, inlet velocity of 250 {m/s}, and gage static pressure of -22.5 {kPa}. The expected conditions at the 0.3 {m2} outlet are an exhaust gas velocity of...
  50. Fancypen

    Ambiguity in part B -- Rocket engine failure....

    Question: A 7750 kg rocket blasts off vertically from the launch pad with a constant upward acceleration of 2.35 m/s^2 and feels no appreciable air resistance. When it has reached a height of 555 m , its engines suddenly fail so that the only force acting on it is now gravity. Part B: How much...
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