brulaz wrote:
wnjj wrote:
...
duty-cycle (not miles but percentage of time running at or near max power output.
Asked about this earlier.
Just what do people mean by duty-cycle?
You've given two interpretations above.
I've read articles referencing "medium-duty" trucks where all they talk about is their GVWR.
So when the O.P says "as HP goes up, Duty cycle goes down", exactly what is meant?
The Duty cycle the the time the engine was designed to last under the normal uses it was designed for. A light duty truck is designed to be worked some of the time and the medium and heavy duty trucks are design to be worked all the time.
Personally I don't read much into the duty cycles of the engines in our light duty trucks. Most of these diesel engines are design originally for use in Medium Duty trucks but at much lower power.
For example:
The 2004 F650 dump truck we have here at work has a 5.9 Cummins that has 215 hp. The is a truck that has a 26,000 GVWR. The same year 5.9 in the light duty trucks had 305-325 hp. The duty cycle on the engine may be the same but in the F650 it will do it with your foot on the floor 100% of the time where as the pick-ups very seldom are run that way.
