Why Fuel Injectors are AWESOME (28,000 fps Slow Mo) Part 1 - Smarter Every Day 281

Hey, it's me Destin, welcome back to Smarter Every Day! You remember in an earlier video we talked about how carburetors work? We made this see-through carburetor, and you can see that there's a bowl... there's the float... there's a needle and then there's this Venturi on top. The wonderful thing about a carburetor is that as the piston draws in the air, that fuel is pulled up into the Venturi, and then it particulates the fuel as it goes down into the cylinder. The slow motion was amazing.

Well today on Smarter Every Day, since we know so much about carburetors, let's go find the carburetor on this old tractor. All right, let's go over to this side of the engine. Gotta open this thing up here... and check this out. I did this earlier; this mechanism is so cool. Check this out. The engine is up under the battery here, and uh the first time I tried this, I took the battery out like an idiot, (laughs) but the way you actually do it is THIS... which is beautiful (clearly excited about the mechanism). Okay, so THIS is the top of the engine, and you'll notice there's not like a carburetor-looking-thing here. Like I don't have a bowl, a float, and a needle or any of that... I've just got pipes going straight into the top of the engine right here. You see that? It says: "Firing order one, two, three." So this is a three-cylinder engine.

Those things right there (let's zoom in) THAT is a fuel injector, and you're smart; you read the title to this video, and you know that we're about to do something awesome. We're about to look at a fuel injector in slow motion to see its spray, kind of like the carburetor when it misted the fuel and the air and mixed it up. Fuel injectors work differently, and I happen to have a buddy that legit owns a tractor parts company, and we're about to go check this out in slow motion.

Let's go get smarter every day 🎵 [Smarter Every Day sting] 🎵

This is my buddy Dean; he owns Cross Creek Tractor, and uh he does all kinds of tractor parts. What do you do mainly?
Dean (flatly) - Tractor parts.
(Destin giggles, clearly they know each other) Dude, you're getting everything out of that!

So Dean started his business years ago doing tractor salvage. Right?
Dean - Yeah.
Destin - So this is... you're getting every usable part off this thing, ain't you? ...And so look at all this, all these used tractors back in here. Are most of them scrap?
Dean - Yeah.

Cross Creek Tractor is an amazing place. They refurbish parts from this huge graveyard of old tractors, and it's incredible to see what they're doing, but Dean is taking it to the next level. He now has a full CNC machining operation where they make totally new parts for tractors as old as the 1940s all the way up to the newer models.

These parts allow people to keep their tractors running, which is really important for a lot of people all over the world, and I absolutely love seeing that "Made in America" sticker Cross Creek sticks on their boxes. I love that. I'm going to be manufacturing some stuff soon, so I'm excited to do that myself. (Seriously, I'm CNC milling as I type this.)

Anyways, whenever I come around, Dean's always talking about how he's making TRACTOR parts. He's not making ROCKET parts, but don't let him fool you; he's doing some really awesome stuff. My old friend Jacob works there, and we got to work setting up a little experiment to explore some tractor fuel injectors.

All right! So we're in the shop; this is my buddy Jacob.
Jacob - Hey!
Cross Creek tractor.

So we understand carburetors at this point; they create a vacuum pressure that pulls in fuel from the bowl and vaporizes it, but injectors are different, right?
J - That's right, they're a totally different system; it's a forced fuel injection.

Okay, so these are different types of fuel injectors, and you were telling me -- I've already forgotten... I know this is international.
J - Correct.
Was this?
J - Kubota
J - Massey Ferguson,
J - John Deere,
J - Ford.

Okay, so these are all different types of injectors. These two are new, and these are sold here at Cross Creek Tractor. Get your tractor parts at CrossCreekTractor.com. I'm assuming that's your website.
J - Always that is, (laughing) J - That's the correct website.

Jacob and I go way back. You were on Smarter Every Day, like episode 20 something.
J - Vortex Shedding.

Okay, so what we have here is a way to demonstrate a fuel injector. Let me turn the Phantom off; it's a little bit loud. So this is a tester used to test fuel injectors, right?
J - Correct.
And how does it work?
J - All right, it's basically a hydraulic pump that has a gauge on it. It works sort of like a floor jack.
J - You would shut off your valve, attach the injectors...
D - Woah! Did I just shoot you with fuel?
J - Just a little bit.
D - Okay, my bad! (laughing) I'm sorry!
J - That's okay.

But then you hook the injector up to it, then you continue to pump that until you build the pressure that it takes to overcome the spring tension in the injector, and then you would check...
D - So it's like a check valve.
J - Just like a check valve.

Inside there, you overcome the spring tension, move the plunger, release the fuel; you check what pressure it pops off at, and the pattern.
D - Can we hook one up?
J - We sure can.
D - All right, which one is this?
J - This one we'll start out with the international.

Okay, and not to use crude language or anything here, but it looks a little like a nipple at the end with little holes in it, and that pattern, uh, dictates what kind of spray pattern you get inside the engine. So what does an ideal pattern look like on a fuel injector?
J - The ideal pattern is going to be even throughout all of the holes that you pointed out at the end of the injectors. If you've got four ports on there, you're going to want to see fuel coming out of all four ports of those. You want it to come out in an even... almost even burst, where it would be evenly distributed inside the cylinder. If you get too much on one side, you get an uneven combustion.
D - Like if you get too much fuel on one side of the cylinder, you won't burn complete on that side.
J - Right, it won't burn complete, and you'll end up with you know... black exhaust smoke, incompletely burned fuel, uh poor fuel economy, and eventually engine failure. So basically you'll have a rich side of the engine and a lean side.
(Agrees)
Yeah, and so that affects temperature and stuff like that.

D - That's interesting because on the carburetor everything happens upstream from the inlet.
Okay, so here's what we're gonna do; we're gonna get this slow-mo video here, and we're going to look at the nozzle... Fuel injection systems are super, super high speed, like CRAZY high speed. So in order to see this... will you flip that light on behind you?

We're going to backlight these things, and we're going to try to get some nozzle spray patterns using the Phantom. Here we go. So we set up a bucket to catch fuel as it sprays out of the injector, and we dialed in the lighting. We wanted to start with this old injector from an international tractor to see if this thing was still working.
J - And we got a little leak, but it'll work.
D - Yep! Three, two, one...
D - Oh wow, look at all that fuel; it was like... it was super, super smoky in a good way.
J - Yep.
D - Come check this out.

This slow-mo is deceiving because it looks like you're just watching liquid come out of a little bitty hole, but if you look down here, that timing is in milliseconds. This event is EXTREMELY FAST.
D - Is that good?
J - That is a... not great pattern... That one you could probably see some misfiring issues on that.
D - Because it's....?
J - Because it's not a uniform stream.
D - What pressure did it pop off at?
J - That one popped off at 2,250 PSI.
D - You would have liked to have seen more uniform streams on that.
J - Right, more of a uniform mist out of the end of it.

D - All right, should we try a new one?
J - Yep!
D - How old would you say that injector is?
J - That injector right there was probably from the late 60s or early 70s.
D - Are you serious? So fuel injector technology is pretty old, pretty old.
J - Pretty old...
D - Really?
J - Pretty old.
D - And this is the old injector you're taking off?
J - And the adapter to fit it to the injector tester.
D - What is this from?
J - That's a Kubota.

D - Kubota... All right, ready?
J - Yep.
D - Yep
D - So you're having to put some force to it?
J - Well, I mean you're building three thousand... on this particular one uh looked like it's about 3,100 PSI, so you're literally... I mean you're using hydraulic pressure, so it's not like you're lifting 3,000 pounds, but yes, you got to put a pretty good amount of pressure on it too...
D - All right, let's see that one.
(Slow Motion Squirting Liquid Sounds)
D - How's that one look?
J - This one is a much better pattern than the one we saw on the last go around. There were more individual streams coming out of the other one, so it's going to give you incomplete combustion. As you can see in this one, it's vaporizing the fuel... atomizing the fuel more, so you're gonna get that more even combustion inside the cylinder.
D - So this is going to burn more efficiently....
J - Yes, like all around; you're going to get that even heating in the chamber, and that's going to be a better, better fuel burn.
D - So this is an ideal... maybe not IDEAL, but it's much better.
J - It's good.

D - Okay... So we filmed a lot more of these fuel injectors in slow-mo, and it was amazing to see the different approaches to delivery and vaporization of the fuel in an attempt to maximize power and performance. A lot of these things have four streams that shoot out radially, which is really fun to watch. I love looking at these things knowing that this can happen up to thousands of times a minute inside an engine. This is fascinating. Thank you very much, Jacob.
Jacob - Thank YOU!
D - Appreciate it! 💥 Pew! 💥
D - I didn't blow it up! 💥 PEW! 💥 (Both Laughing)

All right, this should go without saying, but do not try what I'm about to do at home.... Even if you have really cool safety glasses (chuckles). All right.... turns out... you can buy these fuel injector testers on the internet for pretty cheap. In true redneck fashion, I have a propane torch duct taped to a stick, with that flame tip being right at the end of a fuel injector. This is one of those that's got the four tips on it? ...Like it has four streams of fuel. So let's catch some slow motion... uh, we'll go 6,000 frames per second. One..... Two.... Three <WHOOOOOF!> ........

Oh!... Oh, oh.... oh, okay. (Gathering Composure) All right, let's look at that (Pleasant Music) Wow!!! Oh man.... Okay! (Laughing) Okay, here's what I learned here. When I first started squirting it, it was just liquid... just like a solid stream, but it wasn't until the correct vaporization or the cloudiness, if you will... it was until that started that it actually lit fire, so that's key to combustion; you gotta have the right surface area of the fuel to the air, and of course, you gotta have spark.

So uh.... Okay, we didn't light one of the streams, so let's try it again; let's see if we can get all four to light. I have a mega fire extinguisher just so you know (giggling still). All right, here we go..... One, Two, Three... <WHOOOOF, SLAM!>

Okay...... ....Yeah, I've got to go get a better torch.... Okay, acetylene torch... I'm melting that. Ready? One, Two, Three... <PWOOOOOF!> Aw! We only got three! <FWOOOP!> <FWOOOSH!> <LAUGHING, CLEARLY PLEASED> I'm starting to understand this. I can't see the camera; there's so much light. It's like the stoichiometry is changing radially out from the center of the injector.... and so, uh, it's... yeah!

Think about it! Boundary conditions! Right at the little exit, it's 100% fuel... WAY out into Infinity, it's 100% air. Somewhere in between, there's a boundary; it's a gradient. And so there's an optimum mixture point somewhere between nozzle exit and getting out into the air, so there's this radial boundary that it can't back burn into, and I don't know what you call that.... but we just saw it. So it's like the fuel and the air have to agree that, okay now it's time to burn, and the fire is trying to run backwards, but it can't quite get there because the stoichiometry goes back to fuel-rich.

Very interesting! I want to point out one thing that has just occurred to me. So I am using a torch to light off the fuel on these diesel fuel injectors, but that's not how this would work inside a diesel engine, and I got these really cool old books to show you why. So in this one, there's a really cool graphic showing the difference between a gasoline engine and a diesel.

Gasoline, on the right here, you can see we have a spark plug; that acts like the torch I'm using; it provides the flame which propagates from one side to the other. But with a true diesel engine, it would be more like this. It's the compression and the hot gases being compressed that makes it all explode; that's how a diesel engine works, so that's probably more what these fuel injectors are actually seeing.

Another thing I want to point out is there's many different types of fuel injection. Like, we're talking about direct fuel injection right now, which is basically injecting the fuel directly into the cylinder; that requires really high pressures, but there's also a method called the port injection method where you can have the fuel injector upstream of the intake valve, and then when you open that valve, you can squirt it in there, and that requires lower pressure.

So my point is fuel injection is complicated, and we will talk about some of these other methods in a future video. Here's what we'll do right now; I want to transition from these quad nozzles, I'll call them; I don't know what you call those, to these single-type sprayers because I want to see it spray straight out, and I just think this high speed is beautiful, and I'm learning, and I want to keep doing it!

So, uh, yeah! Let's do some more. 20,000 frames per second.... let's see what's up! <FWOOSH!> WOOHOOOO!

Okay... (Upbeat, happy music starts slow) <FWOOSH!> <Pleasant, Reflective Vocals> <Music Overtakes You, Like the Fire> It looks like the eye of Sauron! Look at that! It totally does! Oh man... It is beautiful though. Ah! That's pretty.

All right, I hope you enjoyed this as much as I do; this is AMAZING! So like... direct injection fuel injection, there's more stuff too! There's throttle body, there's electronic fuel injection, there's port injection... We're gonna learn about all that. I have filmed all this stuff already; I've just got to make the video.

And so a huge thanks to everybody that supports on Patreon. You'll notice there's not a sponsor on this video because Patreon is how I made this thing happen... so super duper thank you. I will shout out a company though! My buddy Dean! He has Cross Creek Tractor.
Cross Creek Tractor.com
Dean - Yep, that's the deal... uh call Jacob and uh blow his phone up and make him have a hard week next week.
So basically, you guys sell parts that like... electrical parts... all the stuff is new... you do used... everything, right?
Dean - Everything... New, Used, Top to Bottom.
Destin - And you do old stuff, and you manufacture new stuff as well...?
Dean - We do, yes.
Destin - Yeah, so if you got an old tractor and you need it run. Cross Creek Tractor.com......