Maximum engine speed

Engine torque is limited to protect the engine from damage at higher engine speeds so that the engine speed cannot increase even more.

Fig 1: Engine Torque Graph (Maximum Engine Speed)

Courtesy of SAAB-SCANIA OF AMERICA, INC.

When the engine speed exceeds 5900 RPM, engine torque will be limited. If the engine speed should increase above 6200 RPM then the fuel supply will be cut.