What is Ignition: Definition and 66 Discussions

An ignition system generates a spark or heats an electrode to a high temperature to ignite a fuel-air mixture in spark ignition internal combustion engines, oil-fired and gas-fired boilers, rocket engines, etc. The widest application for spark ignition internal combustion engines is in petrol (gasoline) road vehicles such as cars and motorcycles.
Compression ignition Diesel engines ignite the fuel-air mixture by the heat of compression and do not need a spark. They usually have glowplugs that preheat the combustion chamber to allow starting in cold weather. Other engines may use a flame, or a heated tube, for ignition. While this was common for very early engines it is now rare.
The first electric spark ignition was probably Alessandro Volta's toy electric pistol from the 1780s.
Siegfried Marcus patented his "Electrical igniting device for gas engines" on 7 October 1884.

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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. neilparker62

    I NIF Reaches Threshold of Fusion Ignition

    Is this a 'big deal' ? https://www.llnl.gov/news/national-ignition-facility-experiment-puts-researchers-threshold-fusion-ignition
  3. phyzguy

    Major Nuclear Fusion Milestone: Ignition Achieved

    https://phys.org/news/2021-08-major-nuclear-fusion-milestone-ignition.html Anybody know any more? Like what they did differently from earlier trials.
  4. L

    Engineering Would the two stroke spark ignition PV digram be same as for a 4 stroke?

    Would two stroke spark ignition PV digram be same as 4 stroke spark ignition. both have otto pv diagrams.
  5. B

    How Can Science and Physics Contain Fusion Ignition?

    Fusion ignition is a self sustaining fusion reaction because the heat is so high that any cooling that does happen due to radiation or loss of mass will not stop the fusion reaction. This is really the key to the dream of endless energy, since fusion will give you electrical power forever...
  6. Charlie Cheap

    Automotive Spark length of a points ignition compared to an HEI system

    Having made/modified my own distributors for years, I was surprised to see MSD (Multiple Spark Discharge) company show their graph using Points, HEI, and Performance HEI comparisons, with little difference in Horse Power made, up to about 6000 RPM. I know a points mechanical system makes a...
  7. U

    I Uncovering the Mystery of the 1991 Atomic Bomb Ignition Papers

    I recently looked at a transcript of a 1991 interview of Hans Bethe, where he recalled the suggestion that an atomic bomb could ignite the air. "Teller at Los Alamos put a very good calculator on this problem, [Emil] Konopinski, who was an expert on weak interactors, and Konopinski together...
  8. H

    In a car ignition how does a circuit work?

    As I get it is that after the contact breaker breaks the contact then the current flows from plus of the battery through the primary winding then through the capacitor and to the minus of the battery. But then what happens to the secondary current? It goes from secondary coil and then what? Does...
  9. hagopbul

    At NIF what is the shape of the 1st stage of the plasma

    Hello all: I was wondering what is the shape of the plasma at Nif ,is it spherical ? I start to wonder that it may be spindle shaped ,or fusiform shaped . Best H
  10. Charlie Cheap

    Automotive Points ignition output voltage and length?

    As the go-to-guy for first generation 6-cylinder Mustangs, I have an unusual question. With a carburetor type engine, operation at 1000 to 5000 rpm, is a modern electronic ignition truly better than a hot points system? After studying both types it seems newer ignitions make a hotter spark but...
  11. M

    Automotive Flash Point of Petrol & Diesel: Pressure & Self Ignition

    Flash point temperature of petrol is lesser than that of diesel at the same pressure. Does this mean, if I take petrol and diesel as liquids in separate containers and heat them, rapid vapourisation (rapid enough to sustain a combustion) of petrol occurs at a lower temperature(fire point) than...
  12. M

    Difference between flash point, fire point and self ignition temperatures

    Is there any difference between setting petrol on fire directly(by contacting it with burning stick) and heating petrol in a vessel, increasing its temperature above itself ignition temperature and making it burn spontaneously? What is the difference between flash point,fire point and self...
  13. J

    Heathkit Model CP 1060 Capacitive Discharge Ignition

    One of my transistor has failed I tried replacing but sticking any transistor in there does not seem to work. Someone from that worked for Heathkit told just look up number this would work except I can not find cross for 230-616. When this unit worked it always put a little wine out I think it...
  14. I

    What influences ignition temperature and oxygen consumption

    Hello, This is for my independent game development project. I am aiming to simulate simple environmental properties in grid-based world. I have world made of cells (or blocks) and I consider each physical property to be constant and uniform in given cell. Some properties spread from a cell to...
  15. eigenmax

    Is the output of my ignition coil AC?

    Hello, I am working on a project that requires both high voltage AC and DC. I was going to use an ignition coil for the AC because I thought it's output would be AC, but when I saw this illustration...
  16. J

    Canister Ignition Protection: How Do Gas Containers Keep Flames from Spreading?

    So, this is just a simple question that crossed my mind. When say, a blowtorch or propane tank is ignited, how does the entire canister not go up in flames? How does the flame only stay on the outside and not burn through to the inside where the gas supply is? Will whatever principle this works...
  17. shimun

    Understanding Alcohol Ignition: The Science and Percentage Explained

    1. Can anyone explain in basic way, when alcohol begins to burn from external fire touch, precisely in procentage. as we kown vodka 40% of alcohol don't fire up. 2. Can anyone answer me in basic way, why is what ?
  18. mfig

    How can I design a spark ignition system with a wider energy delivery range?

    Hello, I would like to design a spark ignition system with a wider range of energy delivery than a typical MSD system. On the MSD systems I have looked at, they are limited to about a 10 mJ range, but I need to go from, say 5 mJ to 1 J if possible. Does anyone know of a packaged system like...
  19. B

    Ignition coil HV pulse on oscilloscope?

    Hi all, I've been using a HV step up transformer (10kV-20W on secondary) lately and I'm wanting to look at the HV pulses on an oscilloscope. The coil is isolated from ground. I know connecting a probe directly to it is dangerous and would ruin my scope. I want to use a differential probe but...
  20. M

    Transformer for CDI ignition power supply

    I have an old motorcycle which I would like to fit with a modern CDI ignition. The ignition would be of the type typically fitted to dirt bikes and which require a high voltage AC source. They have a permanent magnet alternator with a separate high voltage stator for the ignition in addition...
  21. A

    Ignition switch and Battery cut-off

    I have a question that how ignition switch works. Is it is directly connected to battery..? or Alternator..?? Further If I apply a Battery Cut-Off Switch, will ignition works when Battery Cut-Off Switch is off..??
  22. Ali Durrani

    Minimum Ignition Energy of HD-5 LPG

    The minimum ignition energy for propane is 0.25mJ and for propene is 0.28mJ i have a mixture of propane and propene the percent by volume of propane is 95% and of propene is 5%, is there anyway other than experimentation to find the exact value of Minimum ignition energy of this Mixture or if...
  23. R

    Auto ignition temperature in pure O2

    First of all (and I know this is not the place I'm supposed to introduce myself,) I'd like to say hi to the forums. Now onto my question. For the past few weeks, I've been thinking about an idea I had. That idea was to use pure oxygen to oxidize a combustion reaction in an engine. I'm sure...
  24. voltech444

    Oxygen Enriched Internal Steam Compression Ignition Engine (OEISCIE)

    Hello PF members and guests, I have been working on this concept for 2 years and I wanted to get some input from this forum. I have done a lot of research on oxygen enriched combustion and water injection. Both of these concepts have been tested and proven in experiments and the real world. My...
  25. K

    Powering a Tesla Coil with a 12 volt battery--help--

    So I have been wanting to build a Tesla Coil for a while now, and I did not want to make a large one, just enough for a 4 or 5 inch spark. That being said I began searching the internet for designs when I stumbled upon the 12 volt battery variation. The idea is that the 12v battery would drive...
  26. T

    Problems with Fast Ignition fusion?

    I came across these slides http://hedpschool.lle.rochester.edu/2009SummerSchool/lectures/Key.pdf which say that the main problems with Fast igniton fusion are 1. Compress DT fuel to high ρ, ρR around cone tip; cone tip must survive Gbar implosion pressure 2. Relativistic laser interaction...
  27. S

    Is fast ignition fusion a viable approach for achieving fusion energy?

    Was this technique ever demonstrated experimentally, or it could be regarded as practically failed theory? https://lasers.llnl.gov/science/ignition/fast-ignition
  28. E

    Can This New Insulating Board Ignite Quickly Under High Heat Flux?

    Homework Statement A new type of insulating board has been developed by that esteemed construction company Kaput Ltd. They warn that at extremely high heat fluxes it could be ignited, but they don’t think it’s very likely and it would take hours, so there’s no real risk! As an expert on the...
  29. M

    Ignition Coil and Capacitor oscillations

    BOB S had posted this in a now closed thread: https://www.physicsforums.com/showthread.php?t=360072 Regarding this analysis ... https://www.physicsforums.com/attachment.php?attachmentid=20126&d=1250393723 My questions ... Q1) Does this oscillation from the L-C circuit actually...
  30. U

    Ignition coil as Hvdc transformer

    Can a large scale ignition coil drive type circuit can be used for stepping up the dc voltage
  31. 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...
  32. J

    Ramjet Ignition Airspeed: What You Need to Know

    What airspeed do I need to ignite a ramjet?
  33. J

    Plasma Creation Method and Ignition of Self-sustained Reaction in Toroidal Reactors

    Abstract The proposing Method unlike to using now others comprises in usage for plasma creation and its further ignition the created in-situ halo-layer of high-energetic particles to the puffed gas. For realization of Method the following procedures should be performed consistently and...
  34. G

    Question about plasma ignition

    Hi, I am an EE studying some plasma physics. I am doing alright with it, but this question cropped up in my head a few days ago, and I've come to find out that most text-books don't devote a lot of time to it. I am interested in microfabrication, and plasma reactors are central to a lot...
  35. K

    How to start generator with battery (self start) with ignition.

    Hi to all, I have generator 3500watts (Made in China). it has pull start with rope. and i want alternate start with self start...! i hope you understand what i am talking about. Thanks in advance. what accessories or tools required? how to do? how it works? guys i am not engineer...
  36. M

    Thermodynamics and Compression Ignition Pressure and Temp Problem?

    Homework Statement A model diesel C.I engine has a volumetric compression ratio of 18:1 and a cut*off ratio of 1.5:1? The engine has a volumetric compression ratio of 18:1 and a cut*off ratio of 1.5:1. If p1 = 1 bar and T1 = 27°C, determine the pressure and temperature at each point in the...
  37. M

    Automotive The future of the ICE- fuel and ignition

    It is my belief that as a country we shall all be driving LNG (Liquefied Natural Gas), DI (direct injected), Turbocharged, Plasma ignited cars in the very near future. LNG because of the supply here in the US and the L part (rather than C-Compressed) for range and relative safety. DI...
  38. Z

    What is the process called when metal is heated in a microwave oven?

    Recently I came across with one video in youtube where the guy in the video did experiment on microwave oven. He heat up aluminium foil in the oven and after a few second, the foil started to produce spark. This is my first time watching something like that. I never knew that when metal is heat...
  39. P

    Ignition Coil Won't Spark from Mosfet but DOES spark By Hand? HELP?

    Ignition Coil Won't Spark from Mosfet but DOES spark By Hand? HELP!? I'm trying to get an ignition coil to create sparks running it with a Mosfet powered by a 555 timer. The Mosfet is definitely switching. I checked it with resistor, ampmeter, and o-scope. Everything is behaving predictably...
  40. M

    Electric stove ignition causing an EMP?

    Hi everyone, I'm a musician and I'm having a very strange electrical issue with my home studio setup. I'm hoping someone here might have some advice for where I could investigate this further or who I could ask for more information. In a nutshell, my monitor speakers (JBL LSR4326P) are...
  41. O

    How do you power an ignition coil

    Hello, I've just bought a HV Spark Coil from this site: http://www.rmcybernetics.com/shop/high-voltage/hv-spark-coil/prod_4.html And I was wondering if anyone could help me on how I could power it? I'm really poor on money at the moment since I've just spent it on this item, so if anyone...
  42. G

    Can capacitors be used for rocket ignition instead of batteries?

    I've been wanting to use capacitors instead of multiple batteries to launch rockets. I also want to see how a capacitor driven ignitor works compared to a normal battery driven with clusters of motors. I've been having a couple problems. Problem 1:The switch sparks, which I believe causes...
  43. B

    Can I use 24 Volts input to a car ignition coil?

    I'm feeding the current in pulses via 50v 6800 mfd capacitor. Will it destroy the ignition coil instantly, or will just overheat it? It won't be for automotive use but for general high voltage experiments. As long as instant destruction is a remote possibility, it's easy enough to mitigate...
  44. R

    The Physics of Fire: Understanding Ignition & Oxygen

    Does anyone know a good resource that describes the physics of fire (not the album)? I understand the chemistry of it, breaking apart of hydrocarbons, and combining them with oxygen, but I have been trying to figure out what is actually happening on the atomic level. What is an "ignition...
  45. M

    What is a digital twin spark ignition system?

    what exactly is this digital twin spark ignition system?
  46. C

    Ignition voltage in a waste spark system.

    Hi all I have a question concerning the voltage required to initiate the ignition spark in a combustion chamber. I learned this voltage depends on the dielectric in the plug gap. The more pressure the higher voltage, the richer gas mixture the lower voltage,...and so on...there are many...
  47. R

    How do Capacitor Discharge Ignition Circuits work?

    I have been informed that such devices can produce large voltage sparks from low voltage power supplies, but i was always under the impression that capacitors discharge in a manner that is simply the opposite of the charge graph. 1)So how do these circuits work? and 2)Are the US navy using...
  48. A

    How to Design a Coding Circuit for a 1994 BMW 325 Ignition Switch?

    hi! everyone, um new to this forum and would like some help and few tips on designing a coding and decoding circuit to replace my car ignition switch with, for now all i know is the basics of logic circuit operations, still not enough to perform the function. can someone help plis!
  49. 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?
  50. C

    The capacitor in a points ignition

    Hi all In a car old points ignition system, I understand the capacitor (condenser) main purpose is that of protecting the points from getting burnt. The second purpose for this capacitor, could it be to make a resonant circuit among the ignition coil in order to prevent it from radiation...
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