The difference between and indirect injection nozzles.
: Uses a single pumping element and a rotor to distribute fuel to all cylinders in sequence, typically found in smaller vehicles. Fuel Injection pump working principle - Animation
If you'd like to explore a specific part of the system further, I can help you with: A deeper look at the and how it meters fuel. Comparing mechanical governors vs. electronic ECU control. The difference between and indirect injection nozzles