Diesel engines have injectors. There are two basic types. Injector units and unit injectors.
If I remember correctly, the positioning of a helix, which is controlled, by the commanded throttle position controls injector unit fuel flow into the cylinder. The helix is a part of a piston whose movement up and down in the pump cylinder is controlled by a cam much like the cam in the engine. The stroke of the cam is constant but throttle position causes the helix to rotate in relation to the cylinder in which the piston (helix) rides. The amount of fuel delivered to the engine is dependent upon the positioning of the helix in the cylinder. The fuel pump will consist of a cam driven by the engine and as many helix cylinder combinations as there are cylinders in the engine.
Unit injectors operate in the same way but there is one per cylinder and the controls are ganged together to get uniform fuel distribution to each cylinder. These injectors have a similar helix piston arrangement and are actuated by a cam similar to that operating the valve train on the engine.
Aspiration of the engine can incorporate a blower or, the engine can be normally aspirated. When the fuel is delivered to the engine it will speed up causing an increase in the air volume until there is a balance between fuel delivered and the air delivered to the combustion chamber.
To my knowledge there has never been a system whereby the fuel air ratio can be modified like it is with a carbureted engine.
I guess my mind is not as fuzzy as I thought. I went to engine school in 1947. If I am wrong then I will plead Oldtimers disease.
