The first thing is the pre combustion chamber engine.. They have a pre combustion chamber but they also still have a portion of the piston that has is machined to cause air to swirl to complete ignition. Around 70 percent of the total air volume goes into the chamber. A turbulence chamber engine has about 95 percent of the air compressed into it and most of the ignition takes place in there. These engines have flat pistons. You have direct injection where everything happens with in the cylinder bore. The reason that turbulence chamber engines have to have a high compression ratio and glow plugs is because most of the modern designs have the chambers in the heads. The air looses allot of heat generated from compression when it is pushed into a chamber that is in a separate hunk of steel that has a gasket bearer from the hunk of steel that has the cylinder bore where the heat started....As far has the injector /nozzle things goes....An injector or unit injector creates and meters the amount of fuel delivered. Everything happens in itself. All they need is a low pressure fuel supply and they are happy when they get a smack in the head by a rocker arm or some high pressure oil. All a nozzle does is spray high pressure fuel that comes from somewhere else.....Yeh they both have spray tips that atomizes the fuel but it is where the injection pressure is created is important difference.

Why manufacturers and parts people call parts by their "not technically correct name" is beyond me and it really isn't important....but the man was doing a report so I figured he might as well be technically right..

Research it. I didn't make it up.

We use terms and phrases incorrectly all the time. Unless you are going on Jeopardy
I guess it doesn't really matter..It's like the phrase " my engine sucked dirt in it". Thats not right at all but we all know what we are talking about.