Section 14 - Engine Testing - Group 14 Engine Testing - General Information M11 Page 14-3 Definition of Terms On Engine Performance Curve Cummins M11 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 en- gine data plate. 2. Peak Torque RPM (RPM) - Engine speed at which peak torque is generated. This is listed on the en- gine 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 performance curve where maximum horsepower and optimum fuel economy come together. This is the point where Advertised Horsepower occurs. Fig. 1 7. Full Load Governed Speed (RPM) - Defined 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. 9.
Line Haul Rating - An engine that has a line haul rating has a narrow operating range (RPM). A line haul rating is typically used for on-highway appli- cations. These engines are used with larger (more gears, 13 speed, etc.) transmissions with close ratio splits between gear shifts. 10. Vocational Rating - A vocational rated engine has a wider operating range (RPM). This rating is typi- cally used for on and off, or off-highway applica- tions. These engines are used with smaller (fewer gears, 9 speeds, etc.) transmissions with large ratio splits between gear shifts. Fig. 2