Measure car engine speed RPM via the cigarette lighter

[@felixar90]

Works for Valve. Has a super workshop where he makes X-Ray machine, Lasers, electron microscopes & cookies machines Has a DeLorean Come on. How much cool can someone be. This is getting ridiculous.

[@AppliedScience]

I work for Google[x] now. Thanks for the kind words. I really appreciate it!

[@BlackEpyon]

+felixar90 And this is what happens when you encourage your kids to go into STEM fields :D

[@tennicktenstyl]

don't forget working for google.

[@Skleog]

"Good morning Mr. Freeman!"

[@jasonnguyen3224]

prety sure he has a tesla now too :)

[@FranLab]

I always had my suspicions that you were from the future, Ben.

[@kattn01]

Of course you have a DeLorean.

[@blackbird8632]

The delorean uses the PRV engine, developed by Peugeot, Renault and volvo. It was intended as a V8 but the oil crisis caused people to look for smaller engine's. Thus it was made into a V6.

[@RimstarOrg]

From this video I now have both oscilloscope envy and car envy! :) Though I still love my TDS 220.

[@campbellmorrison8540]

Yeah me too, just the scope would be enough to keep me happy.

[@USWaterRockets]

Can't you just measure the RPM by putting the scope across the Flux Capacitor?

[@USWaterRockets]

That's heavy.

[@Flokker]

USWaterRockets Why is it heavy, is there something wrong with the earths gravity?

[@carolynmmitchell2240]

Ryan Willis gigawatts*

[@Afrotechmods]

You are amazing.

[@HennerZeller]

Now that is a proper car.

[@soramyoujoukasei]

This is just about as mind-blowing as your hybrid rocket engine tests. So simple and yet so awesome.

[@trustthewater]

I almost feel bad that your videos teach me more things that are more useful than what I learned in college but all I'm giving you is one view and not the thousands of dollars the schools got.

[@w2aew]

Very cool, Ben! Very cool trick with the Search feature!

[@JRo250]

German Alvarez Indeed. A master of all things Tektronix. Good on them for the nice gesture.

[@BlowDevilUp]

OMG! That thing is a beauty! Your DeLorean is also not too shabby.

[@johnqpublic2718]

Maybe one day you could design your own musical pickup (like on a guitar, with 6 magnets and a coil) and show us how you did it. I bet you have a unique approach. You never cease to amaze.

[@spokehedz]

I clicked for the DeLorean, I stayed for the science.

[@aarongallagher8898]

I was trying to figure out what RPM actually means and after listening to your description now I know. I used your information to figure out how to set my 4 cylinder engine's RPM to 750 using a fluke to measure the igniter (grounds/un grounds the coil with a signal from ECU) hertz. which equaled 25 hertz.

[@etmax1]

typically a V6 is an attempt to reduce crankshaft length but because the ideal angle of 120 degrees results in a very flat engine most manufacturers choose 90 degrees and put balancing shafts in to reduce the resulting excess motion. Interesting that DeLorean chose to play with the timing to achieve similar goals.

[@iSuchtel]

Fuck me, you have a DeLorean... dude, you are awesome!

[@forecaster182]

*****

[@ruuman]

I never asked myself "what car does Ben have?" Its pretty obvious there was only one real choice!!! Great video. Thanks

[@michaelsnyder7442]

Ben, you have my sympathies. I have worked on Delorean's and they were a piece of bovine fecal matter. You must love that car alot. Love that scope, have one at work as well. Congrats on scoring that scope for your shop.

[@shiftymiata]

My favorite KZbinr... Drives my favorite car (which happens to be very rare)... AND I DIDN'T KNOW?!?!?

[@williamogilvie6909]

Emmet "Doc" Brown knew about the strange ignition timing of the delorean and used that feature to supercharge his flux capacitor. Nice scope. My employer a few years ago supplied me with a similar model that has a logic analyzer option instead of the RF/Spectrum analyzer that yours has. I soldered about 20 30 gauge wirewrap wires to a surface mount processor and recorded its every move.

[@RikMaxSpeed]

Great fun seeing what a modern oscilloscope looks like, but even more impressed by the car!

[@henryrobinson9837]

the interference is all that you said plus a fuel pump and maybe a blower motor, i'm trying to find fft usage to diagnose MAF digital sensors on cars ,i'm a mechanic not an electrical genius like you but it did help

[@jeffkurtock6726]

Just look at the distributor cap (see in video "Car engine science: Ignition timing, emissions, mixture"). The plug-wire posts are not evenly spaced; this is what produces the uneven timing.

[@SimoWill75]

I made a tachometer for my car using this principle about 15 years ago. I won't claim originality, because I got the idea after seeing a commercially made one in a friend's car! ;)

[@electronicsNmore]

Very nice scope and video!

[@mikeissweet]

Score! Congrats on your new scope Ben. Very clever demonstration.

[@CoolJRT2009]

OF COURSE you have a DeLorean. You're a legend!

[@davidhoekje7842]

The Delorian has an unusual engine that was also used in some Volvo's. It was a Peugot, Reneault, Volvo collaboration and was known for the odd ignition sequence. They had a few odd traits, notably a habit of being starved for oil supply to the overhead cam. I had a Volvo 264 with one and it was a delight, reliable and smooth and long lived. Not everyone was so lucky and the millions invested in the engine project were mostly lost by the companies that developed it.

[@GGigabiteM]

The reason that the Renault PRV V6 in your Delorean has 90 degree bank spacing is because the engine was made from a PRV V8 engine base. Basically Renault took the PRV V8 and removed two cylinders from the block and heads and a throw from the crankshaft to get a V6 engine. According to the book, the first generation V6 PRV engine (1974-1985) used uneven ignition timing, which explains the strangeness you see on the scope. The second generation engine split the crank pins and got a more even firing, which would probably look better on a scope. I have an '88 Dodge Dakota with a Chrysler 239 V6 engine which has a similar history to your engine. It's basically a Chrysler 318 V8 with the front two cylinders removed and has split crank pins on the crankshaft. Chrysler had a heck of a time getting it to work without shaking apart so it has a huge harmonic balancer on it and the automatic transmission acts as a second flywheel.

[@gordo8189]

Ben, have you checked for interference from the flux capacitor in your temporal displacement matrix?

[@joonasfi]

The spline reticulator might cause the interference in time-space continuum when approaching event horizon

[@TomKappeln]

I did exactly the same thing with a HAMEG in the 80s, working for the Alfa Romeo Racing Team. The only way to SEE the whole ignition system in realtime working.

[@landlockedviking]

soooo back to the future. Neat vid, thanks. That looks like one cool scope.

[@x9x9x9x9x9]

Ben, You just keep getting more and more awesome! YOU DRIVE A DeLOREAN!!!!

[@wizardOfRobots]

Please don't take the average of the periods...Either take 20ms as corresponding to 90 degree phase difference and multiply by four to get one time period; the inverse will yield 750 rpm at idling or take 32 ms as corresponding to 150 degrees and get time for 360 degrees as the time period yielding 781 rpm.

[@mikehernandez5099]

Love your videos, Applied Science. Learn a lot from you, keep up the great work.

[@1hdsquad]

Thank you for your great videos! Its always a big joy to watch them.

[@RobLion]

It's kind of funny, while the oscilloscope makes it easier to play around with the signal, I think it actually makes getting the number you're interested in a bit harder. The microcontroller implementation counting pulses in a fixed period (say, 1 or 2 seconds) would essentially do the averaging automatically.

[@ociemitchell]

You've had a DeLorean all this time and haven't done a video on the flux capacitor yet? Great video as always.

[@russhellmy]

Just be very careful twiddling with the dials on that Tektronix's oscilloscope while it is plugged into your DeLorrean, it has a hidden Flux Capacitor mode that can easily be accidentally activated.

[@StephenTack]

Interesting about the V6... Another oddity would be vehicles without a distributer. For instance Subarus with 4 cylinder engines have 2 coils that are triggered solid state, and there is a "Lost spark" in the cylinder that is sharing that coil.

[@josephhiggins]

Stephen, can you elaborate a bit more on the 'lost spark' (or give a URL)?

[@StephenTack]

Joe Higgins er, also "Wasted Spark" en.wikipedia.org/wiki/Wasted_spark

[@josephhiggins]

Stephen Tack Thanks Stephen!

[@mdasilvac]

Got the same with my Citroën 2CV, no distributor just points and condenser with a lost spark... Tried an analog sensor, but that didn't do the trick...

[@kens97sto171]

Mazda Miata also has a waste spark setup.

[@kittadyne]

Super interesting way you discovered the odd ignition timing.

[@fluffycritter]

My mom had a 1960s Saab that didn't have a built-in tach, and someone had added an aftermarket tach which worked on this general principle (although much more simply of course).

[@KarlBunker]

Can that oscilloscope measure jigawatts?

[@carolynmmitchell2240]

KarlBunker gigawatts*

[@among-us-99999]

carolyn mmitchell no, not in this case. It is from the future

[@ArtturiSalmela]

That is a very nice car you have, Ben! And a cool oscilloscope too :)

[@PixelCortex]

That is one fancy ass oscilloscope.

[@wrOngplan3t]

"you might as well do it in style" - I see what you did there :) Figures you got a DeLorean, things makes sense now, Doc! Just say it, when are you from? You can tell us, we won't tell :P Awesome video as usual!

[@bumelant]

Another lucky guy! Nice video Ben.

[@oisiaa]

That's like a $14,000 scope!

[@redtails]

not just a scope ;)

[@MilitanT07]

$4,000*

[@W00FLES]

MilitanT07 pmgodfrey Owned xD

[@user-qx7tm5df8j]

thats acutally still 14k?!

[@carolynmmitchell2240]

oisiaa I wish he would send me it

[@robbowman8770]

Add a 10kHz low pass filter - passive or active (opamp), doesn't really matter as your tek has amazing amplifiers. As you said, it would also be useful to get the Tek to autodetect peaks in the spectrum - it must have that capability I would have thought, though I haven't used it.

[@berni8k]

Well looks like Ben is working on a time machine now Oh and btw those peaks are clean enough to simply set your trigger point on them and ask the scope to show you the triggering frequency (My agilent scope calls that meshurment type "Counter", a little confusing to be honest).

[@compu85]

Mechanical Volkswagen diesels use a feed from the alternator to sense RPM, the tach is connected to only one of the poles. It ends up making 33 pulses per revolution.

[@misterhat5823]

Why not measure the frequency of the alternator ripple?

[@andyspark5192]

That is a fancy oscilloscope. I like it !

[@DextersTechLab]

i have some old dashboard 'shift lights' in the garage somewhere that use the same technique to identify engine rpm.

[@sitlar]

Wow! That's a really cool oscilloscope!

[@realvanman1]

Boy, that scope looks RIGHT at home sitting in that car, doesn't it! I wonder why they didn't make the cylinder bank angle 60 degrees?

[@gregfeneis609]

I hope Techtronix has improved their firmware release process since the early teens. I lost count of how many times I submitted bug reports and waited on firmware updates (I had to check, they wouldn't notify me)

[@petergregory5286]

Hi,Got to agree with felixar90. A DeLorean! Wow! Some test bed. Regards

[@BalticLab]

Very cool Ben! This video also shows what I keep preaching to hobbyists who design circuits for cars: The car power, particularly from the cigarette lighter, is extremely nasty.

[@sanches2]

car supply lines hide some of the nastiest surprises... 3yrs in the automotive already and i'm still impressed:)

[@redtails]

cars are a pretty harsh environment all-together, not just the cigarette lighter :D Scourging heat in the summer that make laptop batteries explode, freezing temperatures in the winter, condensation when it rains, constant (variable) vibrations, and worst of all: children

[@sanches2]

+redtails you seem to be an automotive engineer ;) I really like the way you put it especially the last factor hihi:) Greetings, Ivan

[@imacmill]

What's so special about the cigarette lighter? Is it just that it's conveniently located inside the car? Where would be a good place to tap into under the hood? Anywhere with 12V on it?

[@AgentOffice]

and why can't you look at leaked ac from the alternator? modern cars have filtered ignition modules

[@costarich8029]

I had a 68 CJ5 Jeep with a Dauntless 225. In the jeep world they literally called it an odd fire V6. It definitely had a loping sort of exhaust sound. Kinda quaint.

[@jhyland87]

The info on the 90 degree firing is really interesting

[@electrodacus]

Great video. My car I think has also 6 cylinders spaced at 90 degrees but is a much modern car so maybe doesn't have this problem (Oldsmobile Intrigue 2002 3.5L) On modern cars you have the info about RPM using the diagnostic port and much more info. I was playing once with an old laptop and a DOS software to reset one error that I had. It was do to an old and cracked seal on the gas tank and the error was something about small evaporative leak or similar.

[@icesoft1]

Yes, the 'Short-Star' V-6s are 90 degree, however GM used a split-pin design on the crankshaft, effectively moving the crank throws to 120 degrees between cylinders.

[@MylesJP]

Brilliant as always Ben! Why is there an inductive electrical spike everytime a cylinder ignites? What were you actually measuring with the plug in the cigarette lighter?

[@roboverholt9959]

I thought the delorian was a fake thumbnail clickbait picture, you actually have one , wow, nice ! :p I saw one in regina canada a few weeks back getting a speeding ticket:p

[@nilssab]

awesome! Can it threshold the FFT and show the inverse FFT of that？ would be cool..

[@MrClaudiodonate]

C'mon, you have a DELOREAN!!!! Totally jealous! Nice video!

[@00Skyfox]

They just gave you a $14,000 oscilloscope? Wow!

[@HeinousAnusOG]

this was utterly fascinating ben, thank you! i need one of those...

[@oocalhoun722]

Won't work on a diesel, though. No ignition coil.

[@darkobul1]

Tell me Tektronix is no kidding by asking 13k$ for it? wow. I am glad they gave it to you. I am sure you will use it well.

[@metou3072]

you could also just look up the alternator specs and measure voltage and current draw to determine the rpm of the engine (yes. it is slightly more involved than this but this is the gist of it so you will have to know what you are doing because you will have to be certain that a known load is being supplied...another words you can not have anything else drawing current from the alternator other than what is needed for the vehicle to run...I'm sure that it can still be done with everything electrical still connected but there is much more room for error because it doesn't take a genius to understand that the more components there are in a circuit...more things can go wrong) but it can be done ...of course an occilliscope would be the better option over math

[@welltekdiagnostics6835]

amazing efforts ..but it would be so easy if you use Lap scoop . also amazing computing as far Cylinder degrees compare to cylinder configuration per Secondos and Revolution ..you are doing good job

[@nickmartinblue]

I wouldnt put my scope attached as a 1-1 probe to a car. Use a x10 scope probe. I am interested how your signal of your inductive spikes looks zoomed out and if you could see the pattern of firing's. Want to upload a csv file of a capture?

[@ColinMacIver]

Scope is in very good good hands!

[@jovangrbic97]

Why wouldn't you derive the RPM from the alternator ripple frequency, as it's directly coupled to the flywheel?

[@YodaWhat]

From the alternator ripple it is easy to see _changes_ in rpm, but not the _actual engine rpm,_ because there is an unknown ratio of pulleys involved. It would have to be calibrated, which kinda defeats the purpose of a simple plug-in measurement.

[@norxcontacts]

When the heck did you get a Delorean?!

[@AppliedScience]

It was my daily driver in high school!

[@MustafaTULU32]

Applied Science I am a little bit disappointed because of not to here the delorean's voice:)

[@Max_Marz]

***** HA

[@IsaacMyers1]

Applied Science wait... was that "do it in style" a reference to BTF

[@transmorpher]

+Isaac Myers NO

[@spinafire]

Wow, a lot of neat information in one video. Does the uneven firing sequence effect engine performance at all? I would figure an even 'beat' pattern would be less strain and more efficient for the engine.

[@TubeWrangler]

The first production V6 engines were all like this: a 90 degree angle between the cylinder banks. These V6 engine blocks were derived directly from V8's - with one cylinder, or "hole", removed from each bank. A much heavier flywheel, along the order of 25 lbs. more of mass, is required for a 90 degree, odd-firing V6 to run reasonably smooth. Some manufacturers (such as Ford) produced 60 degree V6's, and those fire evenly. All modern V6's use the scheme Ben described; the crank pins are splayed for each connecting rod to allow a consistent and even 120 degree firing sequence. Fun fact: The smoothest and inherently balanced engine configuration is the venerable Straight, or Inline, 6!

[@spinafire]

Awesome, thanks for the info!

[@redtails]

TubeWrangler Cool stuff, I always wondered why engines were in a V-shape to begin with, it seems a highly unstable structure compared to 180° in-line

[@KillerBearsaw]

***** 180° would be flat/boxer style engines commonly used by Subaru and Porsche. inline engines have no offset and are [typically] directly behind one another.

[@strengthbuild]

Since my Saturn doesn't have a CMP sensor it uses a method similar to this to determine ignition timing. It sucks it's not that accurate though. If they actually put a CMP in it, I'd be getting at least 40mpg as opposed to the 30 I get now.

[@chefjoesplaylists2565]

Might not work on hybrids and some newer cars. They use a fully regulated DC power busses.

[@cup_and_cone]

Ben, when is the video on building the flux capacitor for your DeLorean? :-)

[@rich1051414]

Years ago I thought something like this would be quite easy to pull off, although I did not have the equipment to allow it to be more than a fleeting thought. You should definitely make a digital tachometer that plugs into the cigarette lighter, I would buy it :) Seems to me that it would be fairly easy to filter the voltage spikes into a usable pulse train, then averaging that out would be simple, and fairly responsive.

[@bugdev]

Why do you have such a cool lab and car? What do you do for a living? Are you an inventor?

[@davidwilkie9551]

DeLorean, grandfather of CyberTruck

[@UncleKennysPlace]

I just googled the price of this beastie of a scope, as I need a new one. It costs one left kidney.

[@LoveMeKnot]

this guy got a deluxo

[@realvanman1]

I was expecting this video to be about using the ripple resulting from the rectified AC current from the generator. But that would require calibration, since the generator drive ratio and number of poles varies from one make and model to another. I've heard of aftermarket tachometers that work this way, but, come to think of it, I believe they're intended for diesel engines (not spark ignition).

[@dpartridge2325]

How did you get rid of the noise of the flux capacitor??!

[@sneakyrt8613]

LS swap the dmc-12. do it. ditch the anemic boat anchor of a v6

[@JeanDAVID]

Nice equipment ! And nice car too !

[@flaglerhub1]

I always said the DMC 12 needs a better engine. I wonder if that straight six out of a supra would be any good.

[@jonathangwynne1917]

You'd have trouble making it fit. There isn't a ton of space in the engine compartment. As much as I love straight sixes, I don't think it would work. You'd be better off with a more modern V6 - I'd probably start looking at the Nissan VQ37VHR. It is compact, plenty of power for this application and very reliable. I've seen people shoehorn V8 engines into the car but it is almost always more trouble than it is worth. They forget how light the car is and it was tail-heavy even with the original PRV-6 engine which meant that handling was never going to be the car's strong suit. It has plenty of grip but when that grip runs out... The rear-end isn't as wayward as a 911's but almost. Rumor has it that Lotus (who did the original engineering) were horrified at Delorean's decision to push the engine rearward in order to make room for a luggage shelf in the passenger compartment. They begged Delorean not to do it and said it would ruin the balance of the car. He insisted on it and they were able to partially compensate by making the rear wheels and tires much larger for better grip. But that just postpones the "moment of judgement".

[@Ma_X64]

Why you guys haven't some special Imperial units for RPM? Like some kings hand rotations which only rotates by 31.317511 degree because of war trauma. :D

[@j.urielfrancomontes7272]

Hi Ben, How may i reproduce the signal on the batery, this in order to simulate any RPM measuremen with the ripple batery voltage?

[@hulladek3]

Ofc u have a DeLorean. Do you still working on MR Fusion or u already done it?

[@jamesanderson6882]

delorian! you glorious bastard! i salute you!

[@Sauspreme]

I learned much from this video, so interesting!

[@andyweb7779]

Nice DeLorean. They were built in Northern Ireland where I'm from. You can check under the carpets some time as the guys in the factory sometimes drew nationalist and unionist political symbols on the floor to annoy each other before putting carpet in.

[@FranktheDachshund]

Ben, if I won the lottery, I would buy the house next door to yours.

[@MaulTechATV]

Great Scott!