What is the engine dynamic curve?

There are generally two kinds of engine curves: one is called external characteristic curve, which represents the output torque curve corresponding to engine speed under the premise of maximum throttle opening; The other is called general characteristic curve, which reflects the fuel consumption characteristics of the engine.

Attached Figure: The ordinate is the output torque of the engine; Abscissa engine speed. The outermost part of the curve is the external characteristic curve, which reflects the dynamic performance of the engine. In the middle is a general characteristic curve (equal fuel consumption curve) reflecting the fuel consumption of the engine under different working conditions!