I'm not sure what you mean, both Otto and Diesel cycles are four-stroke.
In petrol engines power is usually controlled by throttle plate which limits volume of air going into cylinder, and enough fuel is added during the intake stroke (either by injection or carburetor) to have combustion close to stoichiometric.
In diesel engines there's no throttle plate and engine always runs on lean mixture, and power is controlled only by amount of injected fuel, which is done after air is already compressed and hot.
I think we cross-edited, remaining confusion I think was about 2 vs 4 stroke but it's not really relevant so I had adjusted with a nod to when diesel injection occurs in 4.
I'm not sure what you mean, both Otto and Diesel cycles are four-stroke.
In petrol engines power is usually controlled by throttle plate which limits volume of air going into cylinder, and enough fuel is added during the intake stroke (either by injection or carburetor) to have combustion close to stoichiometric.
In diesel engines there's no throttle plate and engine always runs on lean mixture, and power is controlled only by amount of injected fuel, which is done after air is already compressed and hot.