In summary, the question asks how the action of the accelerator pedal affects the rpm of an internal combustion engine. The four quantities considered are compression ratio, air to fuel ratio, ignition rate, and air flow rate through the intake manifold. The compression ratio is relatively constant, while the other three are variable and contribute to regulating the engine speed. The accelerator pedal, linked to the butterfly valve, is the primary factor in controlling the air flow and therefore, the engine speed. The firing rate is dependent on the resultant rpm through either a distributor or ECU input.