Specifications

Definition of Terms On Engine Performance Curve
Fig. 1
Fig. 2
Cummins 1991 N14 Heavy Duty
Engine Operating Curve
Definitions:
1. Peak Torque (N•m [ft-lb]) - Maximum
torque that the engine will produce. Also,
sometimes referred to as COMMAND
TORQUE. This is listed on the engine data
plate.
2. Peak Torque RPM (RPM) - Engine speed at
which peak torque is generated. This is
listed on the engine data plate.
3. Maximum HP RPM (RPM) - Engine speed
at which maximum power is developed. This
is listed with Advertised Horsepower on the
engine data plate.
4. Advertised Horsepower (HP) - Maximum
power that the engine will develop. This is
provided on the engine data plate with its
corresponding engine speed.
5. Command Range (RPM) - The engine’s
operating range from COMMAND TORQUE
or Peak Torque up to the engine’s governed
speed.
6. COMMAND Point - The point on the per-
formance curve where maximum horse-
power and optimum fuel economy come to-
gether. This is the point where Advertised
Horsepower occurs.
7. Full Load Governed Speed (RPM) - De-
fined as the upper end of the engine’s full
load operating range. This is listed on the
engine data plate.
8. No-Load Governed Speed (RPM) - (not
shown) Maximum unloaded engine speed.
This value is listed on the engine data sheet
and in the FPEPS publications.
Engine Testing Definition of Terms On Engine Performance Curve
N14 Page 14-3