The Secret Behind Diesel Engine Combustion Chambers

I'm trying out some new video editing software. So I wanted to cover a topic that would be quick and easy so I can see if this software is gonna suit my purposes or not. So what I decided I wanted to talk about was basically gas dynamics in a diesel engine versus a typical automotive application and how they're different and why they're different. And so real quick, I think most people that are watching an automotive diesel channel like this one are aware of the best example I can think of is a HEMI, right? And when you talk about a HEMI, what makes it a HEMI is the shape of the area where the valve's set in the cylinder head and it's hemispherical, so it's called a HEMI, right? So what we get with that is that you have different designs and different shapes. So they're not all HEMIs, but the shape of a combustion chamber in most gasoline engines is usually gonna be defined by the shape of the cylinder head that sits on top of the cylinder and that shape is what defines the shape of the combustion chamber. What we see different in a lot of diesels, now this isn't across the board, right? This is just for the majority, I guess I would say, is that you'll have a cylinder head that looks a lot like this guy and you'll see you got your valves on here and that this is a relatively flat surface. And so that means that when this is bolted onto the block deck and it's sitting above the combustion chamber, it has no shape or feature to it at all whatsoever. So since in the gasoline engines, you would have a shape in there that defined the combustion chamber, since ours are flat, like the one I just showed you, what defines the combustion chamber shape in a diesel engine is usually going to be the crown of the piston. So whereas in a lot of automotive applications, you will have very kind of flat top pistons or very little features up here on the top, maybe some. We have what we call the toroidal piston, which is the intrusion in the center, the valve that goes around it. This is where our gas dynamics come in as the fresh air comes rushing into the combustion chamber, fills this valve and causes a swirling motion. So then when the piston starts to come up on the compression stroke, the air that's in this area is going to be really violent. So now when the fuel injector sprays fuel, that fuel that ignites with that hot air is going to spread around that area. So again, like I said, I'm just trying to test out some new editing software. So I'm trying to keep it short and simple just by describing that difference. So combustion chamber shape usually defined by the cylinder head on gasoline applications, where it's defined by the piston more often than not on diesel applications. And again, like a lot of stuff that I talked about on this channel, there's almost no absolutes in the world. Are you going to find a diesel that might have some shape to the cylinder head and have a pretty flat piston? It is very possible that you could see that, right? So don't take everything I say on this channel is absolutely 100% all the time when it comes to stuff like this, but generally speaking, right? So now you got an idea. This is what shapes the combustion chamber called the radial piston crown. It's the most popular one out there. You'll see differences in the size of the protrusion, size of the valley, things like that. But generally speaking, flat cylinder head shaped piston for diesels. Hope this helped you guys out a little bit, but more understanding of how diesel combustion chambers work, how they're defined, what causes the gas dynamics inside the chamber. If you have any questions, please put them in the comments. There's going to be more specific videos coming out soon that are going to cover more specific testing on engines and how to use software to diagnose issues and things like that. Those videos are going to be available to members first and not be released to the general public for a few months. So if you want access to these videos that are coming up soon, please become a member of the channel. It helps support us. It can help me provide better videos for you guys. If I can start making some money off this stuff, I would appreciate it. And at the very least, if you can't afford that, that's fine. I still appreciate you viewing the videos. So please like, subscribe. Have a good day.