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. G

    Auto/Motor Schematic for small engine ignition coil

    As above. As I understand it, there is a charge coil and a trigger coil, and some circuitry potted in together.
  2. D

    Why Does Calculating Ethanol's AFR Yield Different Results from Standard Values?

    First I have seen a few forums dotted about covering this subject already, however I couldn't find exactly what I was looking for so I apologise if its somewhere on here already. I am trying to calculate the AFR value for pure ethanol. I am only including oxygen in the category of "air" due to...
  3. J

    Is a Hydrogen-Fueled Internal Combustion Engine the Future of Transportation?

    Very much interested in everything about engines. While the battery EV seems to be the generally accepted propulsion of the future, I think the Hydrogen (Flex) fueled internal combustion could prove to out-perform it in every way. An engine that is designed for Hydrogen, but could also run...
  4. singularcell

    Efficiency and Temperature in Heat Engine Cycles: Approaching Parts B, C, and D

    I didn't have much trouble with part a but I'm struggling with b,c, and d. I considered the efficiency formula for a heat engine e = work done by engine/ qh but i am unsure of how to approach it. for part c) not sure how i can get to Tc without knowing Th for d) my gut is telling me 5/2 but i...
  5. Y

    Timing Marks on Engine, Timing Chain - Conceptual Question

    On an engine, the timing chain has colored links, and you have to line up these colored links on timing marks on the engine. There's typically marks on sprockets, bearing caps, gears. A understand that you have to line these up in order to get proper timing. I understand that is the reason why...
  6. RandiSS

    Finding efficiency of an engine (with attempt)

    This was my first attempt which was not right. But it was at least a percent unlike my 2nd attempt. This was my second which I found on another forum website. It said it found the work of step 1, heat absorbed of step 2, work of step 3, and absorbed heat of step 4. However, the answers to the...
  7. jesusnd12

    Searching for information on the General Electric J31 engine

    Hi, I am currently trying to do a project related to this engine and I am trying to find information about it. I am looking for technical papers, journals or overall description of the inner workings of the engine. I am looking forward for something more in depth than wikipedia. Also...
  8. T

    Power, Rpm, Torque - Horsepower increase for my small engine

    Hello all, the short story is, I am basically trying to get the same ( or a little more) “power” out of a larger lawn mower type gas engine ( vertical shaft) as one of the largest (120 ish cc) chainsaws ( ref the Stihl MS 880 or newer 881 at approx 10-12k rpm and 9 Hp) The parameters are : a...
  9. S P

    As much steam as possible from engine exhaust gas + warm water?

    Hi all, The idea is to generate as much as possible water steam from heat of internal combustion engine exhaust gas. The so called steam generation device is a simple sloped engine exhaust pipe where water from engine cooling and hot gas is fed at the top and all the mix is exiting at the...
  10. J

    I Reaction moment on I.C. engine when we increase RPM

    Every time when you increase RPM on longitudinal placed internal combustion engine, car shake to side in oposite direction of crankshaft rotation. This is reaction moment for change in RPM of crankshaft/flywheel. How this reaction moment transfer to engine block/car if crankshaft is separated...
  11. Astronuc

    Hydrogen-fueled Internal Combustion Engine (ICE)

    https://www.msn.com/en-us/autos/news/toyota-s-upcoming-hydrogen-powered-5-0-v-8-engine-has-the-potential-to-bury-evs/ar-AA15Q9mq See also an old thread - https://www.physicsforums.com/threads/hydrogen-combustion-engines.70653/ But what material. I know that Nippon Steel & Sumitomo Metals...
  12. D

    Should I use a game engine to make a Tontie clone?

    Hi everyone I'd like to make a simple Tontie/Whack-a-mole clone on Android Studio. I was thinking I could just use buttons and not use any animations. Could I do this on Android Studio? Or would I be better off learning how to use a game engine? If so, which would you recommend?Thanks
  13. core7916

    Automotive Websites for getting datasheets for Ford 220HP engine sensors?

    Can anyone suggest sites for getting datasheets of ford engine 220hp sensors (sensor datasheets). Like cam sensors, crank sensor etc.
  14. Abheer Parashar

    Rotating Detonation Engine, the future of aviation propulsion?

    Hello everyone, I am Abheer and I am a high school student. Few days back I saw an article about RDEs (Rotating Detonation Engines). The article said it is the future of aviation propulsion. I want to ask, is it really so that RDEs are future or the low/high bypass turbofan engines will continue...
  15. BurpHa

    A greater force? (A train engine pulling two identical cars)

    My choice is C, which is "equal to." Here is my reasoning: The engine pulls on car 1, so car 1 is having a force acting on it, which pulls car 1 forward. Likewise, the same amount of force is applied on car 2 by car 1 by moving forward with the same amount of force from the beginning. So it is...
  16. Astronuc

    J58 jet engine and supersonic flight

    We've had several threads on the SR-71 (and related craft) and the J58 propulsion system. https://www.physicsforums.com/threads/sr-71-blackbird-supersonic-aircraft.68694/ https://www.physicsforums.com/threads/j-58-engine-inlet-spike.413262/...
  17. Optymista93

    Cleaning of the finned tubes on gas cooler without disassembling

    Hi, I've been thinking about the solution for cleaning a water-cooled gas cooler and would love to hear some advice from the smarter people with more experience. Description - I will try to roughly explain the concept. Gas Cooler is used to decrease exhaust gas temperature. The exhaust gas...
  18. Harikesh_33

    B Question regarding Heat Transfer in Carnot Engine

    ***A Carnot Engine*** is a theoretical engine unlike a Sterling Engine which can be made practically. Some of the drawbacks of Carnot Engine are, 1)The Heat Transfer occurs only during isothermal process(compression and expansion),this is because the working material (ie) gas or fuel used, if...
  19. WumTrudo

    How Do You Calculate Engine Power for Semi Trucks in Various Conditions?

    Summary: Calculating engine power required for semi trucks under different circumstances. Hello everyone, I would like to ask you for help if that is allowed. For a current project I need to calculate engine power needed in watts under different circumstances. This is something that I will...
  20. W

    I Why Doesn't the McLaren Oil in Water Engine Work?

    Here we have an oil engine. Oil is fed in at the bottom of a column of water, rises up and collects at the top of the column, it overflows into an adjacent column which could be of larger diameter, and is fed back into the column of water. I know it won't work but can someone please explain why not?
  21. Strato Incendus

    Writing: Input Wanted A dangerous space mission that requires a lot of helping hands

    As I've mentioned in a few previous threads, at the midpoint of my sci-fi story on a generation ship, I need a disaster that wipes out about a third of the (male half of) the crew. Several people have suggested things like "a virus that disproportionately affects men", but that didn't quite cut...
  22. S

    JavaScript Physics engine with "angular stiffness" at joints

    I have been experimenting with a minimal "toy" physics engine for JavaScript, called verlet.js but now I want to switch to a more versatile and feature rich engine. One feature I would like to use is the ability to assign a reference angle to a pair of segments (i.e. links, i.e. distance...
  23. D

    Sci-fi engine thrust calculations

    Hi all, I'm writing a technical manual for a starship in a science-fiction series I'm working on, I wanted to check with some folks here to make sure my calculations are correct concerning the ship's engine thrust. The ship has a fully-loaded mass of 5 million metric tons. Using its...
  24. Ozen

    Why Not Titanium Alloy Rocket Engine Nozzles?

    Industry standard right now is a copper alloy (usually an aluminum bronze) inner liner to promote heat transfer to the coolant channels and the walls of the channels and outer liner are usually made of an INCONEL alloy, usually either 625 or 718. But INCONEL is VERY expensive and heavy. The...
  25. camerart

    Can a Rotary Engine Efficiently Charge Batteries in Hybrid Vehicles?

    Hi, Have you ever tried to invent anything? Long ago, as a school boy after learning about internal combusion engines, I 'invented' a rotary engine. (It had actually been invented in the 19th century) My dad said "If Fords can't do then you can't" So I stopped. Years later I learned about...
  26. dom_quixote

    Taurozzi's Oto Cycle Engine: A Notable Improvement

    Notable improvement on the Oto cycle engine, invented by Taurozzi in the early 1970s.
  27. Ozen

    Bi-propellant Liquid Fuel Engine Pressures Before Thrust Chamber

    Been reading Rocket Propulsion Elements 9th Edition and got approval from my university to design a bi-propellant liquid fuel rocket engine for my senior design project, and I've been understanding everything so far but I haven't quite found an answer to how the pressure works throughout the...
  28. A

    Measurement of actual CO2 mass emitted from a diesel engine

    I was wondering if there is a method to measure the actual total mass of carbon dioxide (CO2) emitted from a diesel engine used with a generator for power generation (https://www.cat.com/en_US/products/new/power-systems/electric-power/diesel-generator-sets/1000028914.html). Infrared CO2 sensors...
  29. A

    Inconsistent flow rate measurements of an engine diesel fuel

    I am measuring the volumetric flow rate of a diesel fuel using "Turbines" flow meter, both in the supply and return fuel lines of an industrial diesel engine (https://www.cat.com/en_US/products/new/power-systems/industrial/industrial-diesel-engines/18398034.html – coupled with a generator for...
  30. R

    How does a 4-piston, 4 stroke internal combustion engine work?

    Hi, This post is about a 4-piston, 4 stroke internal combustion engine(ICE).Here is an youtube animation for such an engine. I actually have 2 questions. Q1: We have seen in demos and videos that in a 4-piston (ICE) engine, the pistons P1 ,P4 (pair 1) and P2, P3 (pair 2) are in phase when...
  31. D

    B Question about Thermophotovoltaics (thermal heat engine)

    https://news.mit.edu/2022/thermal-heat-engine-0413 This team that developed this device claims it is capable of generating electrical current from a 1900C heat source via the photovoltaic effect. I was wondering if the generated electricity was put through an initially 1901C electrical...
  32. R

    How difficult will it be to build a 'hybrid' Jet engine?

    Hi, Here is a question - somewhat futuristic and at the moment, hypothetical. How difficult will it be to build a 'hybrid' Jet (turbofan) engine? The engine should be able to handle both Kerosene and (gaseous) Hydrogen as fuel. After burning the kerosene for a while, Hydrogen will take over as...
  33. W

    Heat Engine Efficiency: How Ice Water Affects Performance

    Consider mixing ice water with the hot water and vice versa so that the two reservoirs are closer to the same temperature. What will happen to the mechanical/thermodynamic efficiency and ideal Carnot efficiency of a heat engine?
  34. guyvsdcsniper

    Finding an expression for the efficiency of a heat engine

    My book states the answer to this problem is . I have gotten very close to the answer. My problem is my Tc/th and tc/tm are flipped compared to the solution. I feel like I am missing something in my algebra but can't see where I am going wrong. Could I get some help identifying where my...
  35. thomas-anderson

    B Real world problem - Child's toy engine

    I am not sure this is the right forum, but thought I would try, and you can flock me if I am wrong =) I have a real world problem. However, I don't recall ever having studied electromagnetism, thus I don't really have the necessary background to tackle this problem. I tried to speed up my...
  36. JD_PM

    I Understanding the thrust generated by a typical jet engine

    I was reading propulsion chapter 9 of Anderson's Flight book ( J.D. Introduction to flight (8ed., MGH, 2016)(ISBN 9780078027673)(O)(929s) EAs .pdf) and came to Figure 9.18 b) & c), Figure 9.19 (I cannot post the image here due to...
  37. mopit_011

    Force on three Bolts holding up a Jet Engine

    My solution was that there would be a force of 0 Newtons on the bolt as the bolt is not moving. But this answer is wrong. Where am I going wrong?
  38. M

    How to Build an Isopropanol Rocket Engine?

    Hello, I'm wondering how I could make an isopropyl alcohol rocket engine. Currently I'm testing with plastic bottles, and that's not quite exciting. The alcohol quickly burns out because it is just some vapor in the bottle. There also isn't enough oxidizer, as the bottle quickly fills in with...
  39. C

    I Ideal working gas for a Stirling engine

    I was reading around Stirling engines and there's something I am not sure about, can't see a logical explanation. So the ideal gases discussed are hydrogen and helium on account of their higher thermal conductivities. But I am unclear on what motivation there would be to use hydrogen which has...
  40. B

    Net efficiency of a cascaded Carnot Engine and Fridge

    Here is a diagram of my interpretation of the problem: Where I'm thinking that the engine originally takes heat from ##T_h## to ##T_l##, in which case ## \frac { Q_{h} } { T_{h} } = \frac { Q_{l} } { T_{l} } ## and ## W_{out} = Q_{in} - Q_{out} = Q_h \left( 1 - \frac {T_l} {T_h} \right) ##...
  41. berkeman

    GE initiates testing on second XA100 "adaptive cycle" fighter jet engine

    This is pretty interesting. It sounds like GE and the Air Force have been able to make some good improvements recently...
  42. K

    I Theoretical maximum efficiency of a heat engine without Carnot

    Through an intriguing fictitious dialog between Sadi Carnot and Robert Sterling, Prof. Israel Urieli of the Ohio University shows that it is not required to invoke entropy, the second law of thermodynamics, and the Carnot cycle with the [ideal] adiabatic processes in order to find out the...
  43. D

    I Steam flow rate in 2-chamber steam engine system

    Our system of interest has a duct on the left and a piston chamber on the right that make the shape of the letter T rotated 90º clockwise. The smaller tube on the left is abbreviated as P1 has an unspecified length while the piston chamber is P2. The air in P2 heats up and expands while the...
  44. S

    Automotive How long does engine oil really stay good?

    I though engine lubrication oil needs to be changed every few months or every 3 to 6 months, or every 3000 to 4000 miles, no matter what. Last time I had oil change was more than four years ago, and I have not driven the car for more than just a few miles per week, and not more than maybe two...
  45. T

    Cooling a marine engine while testing

    For my internship I have to test and certify a Marine diesel engine. We are trying to run a few tests in our workshop, but this obviously means we can't use the sea or a river as cooling. We bought an IBC tank, which can hold a 1000 liters of water. The water from the tank will be running...
  46. V

    Energy transformations in an IC engine cylinder

    A drop of fuel is ignited in an engine cylinder, that produces heat, light and sound energies from the chemical energy stored in the drop of oil. What I am not clear about is how heat energy gets transformed into mechanical work? I think the heat energy produced from ignition flows from burnt...
  47. ZdMh

    Automotive Can I convert a combustion engine car to a hybrid car?

    Hello all, I'm thinking of converting my car to Electricity. I know that some internal systems have to change. Can that work? and how?
  48. P

    A Carnot engine between the Earth's poles and equator

    Earth absorbs and releases a massive amount of energy as a part of the day night cycles.(~100 Peta watts of solar radiation received) And the temperature difference between the poles and equator drive weather phenomenon, which happens at an energy scale beyond technology. I am wondering if one...