The Spark Plug Story
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The spark plug, a crucial component in gasoline internal combustion engines, has a rich history dating back to 1859 when Belgian engineer Jean Joseph Étienne Lenoir first used it in his coal gas and air engine. The design was refined by inventors like Nikola Tesla, Frederick Richard Simms, and Robert Bosch, with Bosch being the first to develop a commercially viable spark plug.
Spark plugs ignite the air-fuel mixture in the engine's combustion chamber by creating a spark between two electrodes separated by an insulator. The spark ionizes the gases in the gap, causing a rapid surge of electron flow that ignites the mixture, creating a controlled combustion event.
Early spark plugs used mineral insulators and had short lifespans. The introduction of sintered alumina in the 1930s improved insulation, strength, and thermal properties, allowing higher voltages and better self-cleaning capabilities. In the 1970s, lead-free gasoline and stricter emissions regulations prompted further redesigns, including the use of copper core electrodes to improve self-cleaning and prevent pre-ignition.
Multiple ground electrode plugs and surface-discharging spark plugs were explored in the following decades. The 1990s saw the introduction of coil-on-plug ignition systems and noble metal high-temperature electrodes, enabling higher voltages, stronger sparks, and longer service life.
Modern spark plugs also incorporate ionic-sensing technology, which allows the engine control unit to detect detonation, misfires, and optimize fuel trim and ignition timing for each cylinder. This level of control has pushed engine designs to be more efficient and powerful.
As electric vehicles become more prevalent, the spark plug's evolution may soon reach its end, with electricity both pioneering the emergence and likely ushering in the end of the internal combustion engine.
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As an old-school retired mechanic, I had no knowledge of the current use of the spark plug itself as a monitoring device. Excellent well researched video.
en.wikipedia.org/wiki/Saab_Direct_Ignition
Believe we were trying to do that in the mid 2000s on megasquirt detecting knock from ionization.
I tip my hat to the engineers that came up with that idea. Awesome!
Research never stops...
It’s amazing how much spark plugs have improved in such a short time. Anyone who is at least 50 remembers when we had to clean or replace our spark plugs every few months/few thousand miles. These modern plugs will go 75,000-100,000 miles or more without even needing to be cleaned! I remember when you would pull them and clean/regal them every few months and they still would wear out and need to be replaced after a year or two. My current car has over 100k on it and I only replaced the plugs once! Honestly they didn’t even need to be replaced at 50k but I just got nervous and changed them out because I was worried they would get sized in the heads after being in there for 5 or 6 years! Anyone remember points? Yea we used to have to do a lot more maintenance on cars back then. Granted modern cars have lots of other problems and I’d gladly go back to points and the old plugs, it really wasn’t bad having to replace plugs and points every other oil change because those older cars were a lot easier and more pleasant to work on compared to these late model ones where you have to take half the car apart to get to anything. Leaded fuel didn’t help fouling but the real improvements are in the materials. Those old plugs just wore out the gap got bigger and bigger and after a few months it got so large that the engine started misfiring. When I pulled the ones out of my current car after 50,000 miles the gap was almost the same as a new plug! We’re talking about maybe 0.010 wear, those old school plugs eroded that much or more in 5,000 miles.
Yes...I haven't seen a gapping tool in a long time...
Some of us young folk still know how to take an emery cloth to a points dizzy! And truthfully, I agree with the sentiment behind going back to points and old plugs. I daily drive a 77 Mercury Cougar and do all my own maintenance on it. Oil changes, brakes and bearings, carb and timing adjustments, and most importantly diagnosis... I can do it all with simple tools and from the comfort of my own garage. Some people call me crazy for driving a gas guzzling land yacht but honestly I wouldn't trade that kind of straightforward, analog, accessible ease of work for a newer car. Hearing recently about Dodge's new non-serviceable transmission, in addition to watching a very disappointing video review of their new Hornet SUV (from a channel here on KZhead titled "The Fast Lane Car"), really made me take a step back from the idea of the modern automobile. In an age where planned obsolescence and reliance on technology are becoming more and more prevalent, I think it's increasingly reasonable to seek a product made at a time when planned maintenance and longevity were the premiere focus. I really do.
Yes, BUT, the cars with these more sophisticated system can be absolute hell to deal with when they do develop problems, and they all do. For myself I prefer simpler less efficient designs that have fewer parts and are easily serviced. I don't care if I have to replace my spark plugs, cap and rotor every few years. It's easy to do...
That is a much more common dilemma for Diesel glow plugs... try it on a straight-6, 3.0l Mercedes diesel with 650,000 kilometers! (it wasn't pretty)
This is all way above your pay grade.
@3:38 once the ionized channel starts to conduct, voltage goes to near zero because it's practically a dead short. In reality it pulsates rapidly because the ionized channel will get blown out allowing a voltage to build up again so you get a few sparks.
Yes, the video is more like academic paper (but dumbed down for children), rather than practical guide.
Damn you beat me to it! Interesting video otherwise though, honestly didn't know that's how the Saab knock sensing was "so special".. smart people working there for sure.
@@Pelletajuton1 If you keep the spark on you can measure current flow on the low voltage side and determine the temperature in the cylinder. The ignition coil is fed a square wave in electronic ignition systems.
This channel became my new favorite since uploading more car content.
Spark plugs arent for cars, they are for ovens to light the stove.
@@canoaslan1011 your brain on mcdonalds
Bruh, same!
mcgronalds burger
@@cammi_sammi guys dont give me shit because you guys dont know knowledge. its common sense, whos going to know best, this channel, or me? exactly, argument over. Next question please, ask me anything, aaaanything. If i get alot of likes, at least 6 or 7 ill make a video. you guys know what to do, go on.
Engine being assembled at 15:06 is a Volkswagen 1.4/1.5 TSI. just a random thing I noticed
Mk6 Golf motor?
My father invented a self igniting spark plug, it contained a piezo crystal and used engine compression to put pressure on the crystal causing it to make a spark, a man from the patent office came to see the prototype in action and was impressed to see a 250cc engine running with the plug, it was to receive a patent but my father could not afford the fees at the time and it was shelved. The plug needed more development as i found out when i tried it in my Yamaha FS1E 2 stroke, i think the compression was too low, but it had potential even as a get you home device should your cars electrics fail, i see piezo electric ignition on model engines these days but they dont operate the same way my fathers did
Ford Triton spark plug: “Ight imma head out”
The introduction of unleaded fuel was great for our NSU Ro80 back in the 80s. The Wankel engine had a pretty unique plug design that was easily fouled by lead (and the generally terrible fuel quality in Australia…). Needed to clean plugs pretty often, but unleaded fuel cured it totally.
Wow, the beauty of the internet spreading knowledge. I had no idea that the spark plugs themselves are reading detonation now and also can detect misfire at EACH cylinder...amazing.
Thank you for all your awesome work! 🙏
It reminds me of Tolstoys: "A spark neglected burns the House" Amazing explanation 👏
A primary reason for the switch from distributor to distributorless ignition systems is coil life. Beyond the increased wear on distributor cap and rotor conductors, having just one coil limited the peak voltage by what the coil could recharge to. It doesn't take a long time for coil saturation, but when you have a six or eight cylinder engine running at higher loads and RPMs can cause issues. Having a coil only firing once or twice per complete firing cycle allows them to run cooler, last longer, and provide higher voltages.
You may want to add energy loss in cables too… just saying.
That's an answer to a problem that doesn't exist. Old cars with distributors run every bit as good as cars with distributorless ignition. They maybe a percentage point or two less efficient, but they are far easier to service because there's no (expensive) module to burn out...and wonder where you're going to find a diagnostic tool to test it with. On top of that, a lot of companies are discontinuing replacement parts for those earlier distributorless systems, making the prospect of keeping cars from the 90s on the road much more of a challenge. Because the parts are more sophisticated, they require more volume in sales to justify their production. Older cars with simpler parts cost less to keep in the market place.
@@tempest411 This is probably one of the worst takes I've seen on this. Higher ignition energy is required for higher output engines, which modern engines are. We're talking cylinder pressures more typical of race engines in the 80s than regular cars. This higher energy puts more stress on any arcing part, eroding it faster. I have had a lot of experience with carbs, points, distributors, early electronics, early and modern distributorless, and fuel injection systems from K Jet to 2024 model year direct injection. I built several hot street engines, and once you're having to run an MSD or other high energy ignition, the cap and rotor life goes down to about 10k, and that's if it doesn't start arc tracking and misfiring. The "unreliability" of modules is a myth as well, a lot of perfectly operational ones were condemned as a black box that nobody understood, and diagnosis isn't hard once you've actually worked with this stuff for a while. I've got 30 years now across all these various iterations of ignition and induction, and I'd gladly take a 100k+reliable electronic system over having to adjust my carb because it's 2° warmer today, or I had to fill up at a different station.
@@jaredkennedy6576 To each his own. I worked in the auto parts business since the late 80s. We had the equipment to test these components for our customers and I can tell you they work great for between 100 and 200k, but they do crap out, and the aftermarket ones are garbage. Many of the OE parts have been long since discontinued, not that many with a 30 year old car are eager to pay what those parts cost anyway.
@@tempest411 I spent five years running a fleet of 48 medium duty delivery vehicles, mostly running GM L96 engines. They ran 150-200 miles daily, and well over 300k. Usually I had to change the plugs and wires at 75-90k, depending on the specifics of the use, and the engine at 200k. The oil pressure usually dropped way off around 220-230k, so it was preemptive. I replaced engines, throttle bodies, harnesses, transmissions, differentials, but not once did I ever have a computer failure. None of the Fords did either. Same with the Mercedes and Cummins diesel ones. Now I've been running a smaller fleet in the rust belt with the same company, only 31 vehicles, for the last year and change. Still no computer failures, and I've had cars with over 700k. These things get thrashed by the drivers 8-12 hours daily, and soak it up. If I had to do a cap, rotor, and copper core plugs every 12k, there would need to be another tech here to keep up.
Ion- sensing ignition systems are very rare still to this day. I just had a 2020 f350 in the shop with the new 7.3L gas v8 engine. It had the same old school ignition coils/plug wires and it had four knock sensors. No overcomplicated ignition systems to be found on that engine.
Soo much I didn't even know I didn't know :)... Thanks for an excellent video !!!
An interesting extension of this technology is Mazda Skyactive engines which use this sensing to adjust valve timing in a way to, effectively, change the compression ratio of the engine constantly (allowing some blow by the valves on purpose during compression). Would not be possible without the extremely granular information about the state of combustion and knock.
i watched this for my saturday night shindig. you guys are awesome for helping me gain more understanding on the topics you educate us on... the pace, narration, structure of the "lesson" and all round wisdom in your vids are pleasant to behold ❤
The problem with the internet is: "educators" themselves are not educated enough to tech others. Go figure.
Thank you for sharing with us!
Thanks, still trying to figure the copper alloy center electrode being able to handle a greater heat range then steel as copper & brass electrodes were tried 100 years ago and eroded/wore out quickly.
Iridium Tipped FTW long life spark plugs // I even installed one in our 19 Honda Grom SF & it improved ignition performance // along with an O2 sensor & fuel commander //
thanks for the video man i really enjoy them❤
As someone who saw mechanics clean the spark plug as first level of troubleshooting in a two stroke scooters of 90s, I always wondered why we never had to change them even after 100k km's in newer cars.. This explains it so well..
Lean or rich conditions killed plugs easily modern engines have map n 02 sensors that keep them lasting over 100k.
Isn't that a reupload? But i still love it. :D
Very very informative video , is this correct that temperature in between two electrode reaches up to 50,000 °C ?
I am not a mechanic but I enjoy getting this knowledge. Thanks for the upload
i literally changed my spark plugs on my e46 and this video came up lol
Excellent as always
I thought they were cheaping out when the went to the steel stay-in-place washers from brass/copper! But, sure saved a lot of dropped washer time!!!
Champion was a common plug as a kid, and they are more into making jet engine igniters used on airliner jet engines, and such, really hi-tech stuff. Always liked Champion.😇
Anyone else wondering why one spark plug randomly jumps out at 2:04?
Fantastic video. Thanks
Thank you for having the ability to make learning new things so easy and effortless
These things are basics covered in the textbooks from the 60'-70's up.
@@GrandePunto8V there are way better as amazng videos
Great video. Thanks.
Please do one on Seals!! It’s one of the most complicated things for me to understand
Small correction in 13:05, higher octane fuel is more resistant to pre-ignition because it is less reactive, which is not the same as volatile 😉. This is the same as saying that the auto-ignition temperature of the fuel is higher.
Lots of interesting details here, even forgiving some subtle inaccuracies others have mentioned in the comments. I was quite surprised to learn that modern gasoline engines also use the spark plug as a sensor to detect running conditions. One thing slightly outside of the scope of this video, but quite related though: Why in the hell are some engines designed in such a way where you literally have to remove the entire intake manifold to replace the spark plugs?!
Ten pounds of shit in a five pound bag.
To answer you question you dont need too pull the plugs every now and them like back in the days most of the time a good modern plug will out life the engine it is in and the coils seams too be fairly strong too and even with preventive maintainace a engine will only eat 2 or 3 Sets of coils in its life soo yeha it just isnt needed
@@TheLtVoss Yeah, about the coil packs. Kinda helps when the mechanic that installed the last set of coil packs actually plugs in all the wires correctly. We had to pay like $120 for a new set of coils, only to end up with the mechanic botching the job and didn't have cylinder 1 plug wire properly plugged in. It was just kinda jammed in at about a 45⁰ angle under the rubber boot, bent the connector at the end of the wire, and ended up burning up the replacement coil pack due to arcing at the connection. We almost had no choice but to have the plug wires replaced due to that crap, which would have required removing the intake manifold and all that good jazz. But I managed to salvage it, at least they gave us the old set of coils and 2 of the 3 were still good. So I did that coil swap my damn self to make sure it was done right for a change, and I salvaged the plug wire by bending the clip back into shape, wire brushing it clean, and making quite sure all the plug wires were completely plugged into the coils this time. Saddest part is the mechanics that botched the job had just recently done all the surgery to replace all the plugs and wires, only to screw up one of the wires and burning out not one but two coil packs, from the same plug wire no less! Honestly I don't really know if that wire goes to cylinder 1 or cylinder 4, nor do I really even care, it's a double fire coil pack setup so either way works. Sorry for the random story/rant, but thanks for coming to my Ted Talk LOL!
Say hello to my gen 3 Mitsubishi montero. An amazing suv but it sucks to change my plugs because of all the crap I have to pull off
Some crappy new cars have entirely too much stuff packaged into too small a compartment with no consideration for service and/or lots of crappy plastic stuff and water pumps placed where when they leak coolant will mix into the engine's oil.
I found another favorite channel 😊
Could you create a video explaining how ECUs function, focusing on design implementation aspects such as AUTOSAR, as well as tuning?
8:13 these are things I didn't know about unleaded fuel, and makes me think deeper about the fuel I put into my 1928 Model A
I'm sure its not too big of a deal since you can manually retard the ignition. With proper leaded fuel, you could probably advance it more and get better fuel efficiency.
figure out how to get 100LL aircraft fuel, its leaded
the ford model a was designed to run on just about anything that burns. leaded fuel was not yet the standard, something simmilar to what we call white gas or coleman fuel today was. running on straight ethanol, methanol or even wood gas was also legit
Really old fashioned gasoline engines had to run on bad gas that was very low octane and also created lots of deposits inside the combustion chambers. Requiring the engines to run very low compression ratios (large combustion chamber volumes) such engines could probably tolerate having the compression raised by such as shaving the cylinder heads a little bit when using modern gasoline
anyone know of a aftermarket ecu that uses that knock detection system with the plug?
,,, don't know , but Motec usually gets wherever first ,,, !
Not sure for which vehicle you are looking, but Haltech (Australia) seems to have this functionality.
@@Stratos1988 ,,, I haven't been looking , but I tend to like stand alone ( even within the ECU ) stuff . I'd have to work with something like this , to build up skill and trust ,,, !
As a Emergency Mobile Mechanic..Heat range on spark plugs critical...These spark plugs with multiple ground electrodes/ 2 or more..cause heat range dilema...One good ground electrode with proper heat range number is all you need..Of course..Rotary engines use circular ground design for clearance..Double check part # for these or damage internal$$$$.....
The system only builds voltage to what it needs to jump the gap. Gap too big,requires more voltage which may be harder on the spark plug and high tension wires. Modern systems can withstand/produce more voltage allowing a bigger gap. Coil on plug reduces the loss of energy or chance of deterioration of long high tension wires (with coil on plug the energy goes most of the way as low voltage higher current)
Wish you would have mentioned aviation spark plugs, they have a long and interesting development history, too
Another great video!
A few extra seconds regarding "flame-front propagation" would have been more illustrative for ignition timing... possibly also pros/cons multi-cathode ("shadow") ..although ionization of Oxygen/Nitrogen mix vs. atomized Gasoline/oxygen/nitrogen would be a bit much.
Amazing video!
Brilliant!
ICE engines will never be obsolete. Nice video.
wouldn't it make more sense to call them fire engines? oh right firefighters patented that; what about boom boom shocky shocky engine? Dielsel is squeezey boom engine
@@phobosmoon4643Let's start calling electric cars mobile uncontrolled toxic fume generation devices.
Not obsolete, niche yes.
@@rogerk6180 I don't think there's anything niche about the military, construction, mining, aircraft... All sorts of areas where bulky batteries wont do. Among other issues.
They absolutely will, maybe not in the next year, next decade, or even century, but eventually they will, without a doubt, become as much a relic as steam technology is today
I love your content I’m thinking about starting in Hindi myself thank you for the inspiration ❤❤
good one thanks
Was this video reuploaded? It's extremely familiar
At 12:39 I’m not a mechanic but isn’t the spark plug upside down in the illustration? Just curious.
Wow your channel is more informative.
Excellent video.
Can you do a video about: Harmonic Drive, or Strain Wave gear. 🎉
I remember my dad tune up is taking the spark plugs out cleaned them with a WD-40 and a wire brush and gap them 😂 and we were ready for summer vacation 😅
Very interesting. Thou from I read, no one is using ion measurent for detecting knock in commercial sense. Saab did, but it never caught on…?
BMW used it on their s85 V10. Although that’s some time ago now. I believe Mazda skyactive uses it also.
One of the best, if not the best informative non-pritical video documentary of spark plugs I've ever witnessed. Now if I was to purchase electric vehicle, this guy should be your salesman. I cannot explain it. Any clear he's simply put why electricity is the next best thing and is inevitably the future as well as its past. A combustion engine will not combust without a spark. You have to have a controlled explosion fire and an uncontrolled explosion is chaos a bomb. So I injured a controlled bomb. The cylinders the engine walls. They all controlled the heat of the explosion. Electrical engines have possibility of eliminating this putting all the power directly into the tires.
It blows my mind every time I change sparkplugs, even the double Iridium are relatively cheap and last from 60k to 120k mi
All these technologies and their developments will sadly die out quickly. Ice engine technology is just marvelous, i hope we will see the same amzing technological advancement in the new and exciting electric field going forward.
Nikola Tesla patented the capacitor-coil-point switch ignition system in U.S. Patent 609,250, approved August 16, 1898. Tesla did not develop spark plugs, the ignition patent came when Tesla was developing electrical oscillators.
You're a champion ya got a head like a spark plug.
Way to spark, AC!
Removal of lead reduced resistance to knock (sometimes incorrectly called detonation), not pre-ignition. Not the same thing.
14:45 I drive a 1993 Saab 9000, and it has direct ignition system with ionization sensor, it was from the early 90s, not late 90s. Its system looks like what today engine looks like, but a simpler one, I guess it was pretty ahead of its time back then. I know that it did its job as when the system started to fail, it began misfiring and stuttering, the system was there to extract more efficiency out of it and doing so at its limit with help of such sensor, but as it was early design of such thing, it was over-engineer and is damn expensive. Saabs are very reliable, but cost of repair is high, you got to stick to maintenance very strictly.
What was expensive? And what part of the engine was over-engineer? The lack of cam facers? The lack of direct injection? At least in Europe a DI ignition pack at the tme could be bought for arround 250 Euro. Not much for 4 ignition coils and electronics. It was at the time more expensive to change the 4 coils on a VW/Audi 4cyl engine. Edit: The ION sense function and DI coil pack was put in production 1988 in 9000CD turbo.. But in the beginning they used to ION sensing for missfire and cylinder/Cam sync. 1993 they started to use the ION sensing for knock detection.
Trionic 5!
Those coil packs are practically unavailable now, unfortunately. I do wonder if a replacement could be built up from more commonly available parts.
@@jaredkennedy6576 In Europe there is plenty to choose from. Both OEM from SEM and none OEM copies. For Pre T5, T5 and T7.
13:00 you claim that higher octane is lower volatility. This is incorrect. Shorter chains have a higher octane rating AND are more volatile. Hence propane having >100 octane, while obviously far more volatile.
I love your content. Thank you, Mr. Sir!
Edmond Berger, a freed slave, invented the spark plug in 1839. Berger is credited with the invention even though he did not obtain a patent. The spark plug is a key component of all engines, using electricity to pass a spark between two electrodes to ignite fuel and generate power.
No mention is made of the 1839 patent holder and inventor of the spark plug , Mr Edmond Berger, i wonder why.
Well made
Re-upload? Or am I just confused again?
Was thinking the same thing🤔
Me too !!
What an ancient piece of technology, it's as technical as a flint cutting tool
Great video bro
Good enough for general public.
Jean Joseph Jingleheimer Schmidt, his name is my name too...
Good video. I agree with what’s his name.
Unless ALOT of improvement is made in the range, recharge time and price of electric vehicles the spark plug is not going to disappear any time soon.
I always rated the NGK plugs.
Do you guys plan on releasing more videos about diesel engines?
Pls more content like this one!
These are BASICS covered already in the automotive textbooks since the 70's.
Re-upload?
It might be.
Definitely is I remember watching this video
I've definitely watched this prior
@@nowackytobaccy2943same
100% only clicked on the video to see all the "re-upload" comments. Was surprised one wasn't the top comment.
Great video! I have a 5.7L hemi that it eats spark plugs, one year and they’re already out of gap specs haha
Can you get platinum and/or dual strap electrode plugs compatible with it? (Some of those plugs don't have adjustable gap,if new plug out of spec it is defective)
is there anything that changed? I think I watched this already
Folger spark plug vs ac lawsuit interesting it was brass and mica ac 's was porcelain and improvement
i love my ngk rutheniums
Had no idea my Saab did that 😅
voltage required can be AS LOW AS 15000 VOLTS ............
No mention of laser plugs?
Bring back leaded fuel! I really miss pumping Ethel.
@1:16 Archaic? It's exactly just like modern ignition coils on all gasoline engines. It's literally the same.
Same essential technology, yes. But these days they're made quite a bit smaller and are sealed in epoxy, making for a much lighter and much more reliable coil assembly that can withstand tens or even hundreds of thousands of miles of engine vibrations and bumpy roads.
Also they use semiconductor switches like MOSFETs instead of mechanical switches. The basic induction principal stayed the same but everything else is new technology.
Multiple-electrode spark plugs are nothing new, and in fact were quite the thing in the teens. Soon, though, everybody realized that more voltage to the firing surface, rather than more surfaces, was what was needed, and they died out.
He literally stated it was to extend service life.
video re-uploaded
Modern electric vehicles can go farther on one charge than early gas vehicles could go without spare parts.
Clicked right away!!
Cool 😎
Internal combustion engines are gonna be around for decades if not an entire century more.
This is a re-upload!
... excellent, thanks :)
Mediocre, thank me later.
During the Vietnam war they tracked enemy vehicles deep in the jungle by looking for ignition from the air. Dragon Fly or fire.
Contrary to what 99.99 percent of people believe, the Bosch spark plug was neither invented, neither designed by Bosch. It was invented and designed by an engineer employed by Bosch. Bosch was the business owner.
videos like this spark my curiosity.
Bosch shouldn't get credit for their fine wire plugs.
3:30 - wrong! The voltage should drop after the ignition spike. Look at typical "secondary waveform" for reference.