Basics

This paper aims to go over the history/technology behind Fuel Injection in the context of Diesel Engines (ie Compression Ignition Engines although there is probably overlap with RCCI Engines )
It will also then aim to delve into Hardware+EFI Software and other questions related to actual hardware development
- Either from a scratch built Billet Engine or from a White Label Single Cylinder Diesel Engine modification/iteration project

Older/Lower Tech

These injectors are basically a metal syringe fed via a low pressure fuel supply (akin to thay used to fill a Carburetor Bowl
A Camshaft then presses down the piston inside the injector spraying the fluid out
A spring then returns it to it’s starting position
Due to low pressure and larger orifice size they don’t atomize the fuel as well
- They do have less issues with clogging though making Fuel Cleanliness less of an issue, re Fuel Polishing etc
Akin to the issues facing pre-Pneumatic Valve Springs racing engines, this may limit the upper rev range of the engine before other factors do
- Although high rev diesels aren’t needed that much, but still a factor to consider

These are oil actuated or electrically tweaked/monitored (yet still camshaft actuated)
May be more reliable than some modern systems, but odd “middle” in a situation where high tech or ultra low tech may be preferable

This used a high pressure pump and reservoir (the “common rail” + tubing) and all that the injectors do is simply open and close a valve
Often driven by a Piezoelectric Actuator
Atomizes Fuel Better + More Independent of Camshaft/Rev Range Limitations
- Especially models using VERY High pressure (grab spec sheet)
Tend to have tighter tolerances and more requirements for Fuel Cleanliness etc though so this can cause issues
Also some options run into issues with Right to Repair / Design for Repair issues/part availability