4x4ord wrote:
This is the torque curve for the PACCAR MX 13 that’s Peterbilt uses in their medium duty truck
Looks like PACCAR is unaware of the 1800 rpm fuel saving rule.
I think you are a little confused as to what that 1,800 rpm rule is. It is the rpm at which diesel burns most efficiently and completely and there for will generally have the highest thermal efficiency for the amount of power it is creating around that rpm. Basically, it is the point at which you get the most out of a drop of diesel fuel. This is not to be mistaken for the spot at which an engine is using the least amount fuel or the different rpm ranges to make power for different applications, industry needs, or rpm limitations due to engine size.
