I have been trying to understand the torque curve and power curve of an engine. From what I have read and understood I know that the torque curve and power curve is has a peak at a particular RPMs(RPM is different for torque curve and power curve). I also understand that when the engine is running at a particular RPM it will be producing a particular torque(drive torque) and if we increase the load on the engine(increase the load torque) then the RPM will start to decrease. To keep the RPM from decreasing, we can open up the throttle( which will increase the fuel burnt and so the energy produced at the power stroke) and so, increase the drive torque being produced to match the increased load torque.
What I am not able to understand is if the torque value at a particular RPM shown in the torque curve is the maximum possible torque at that RPM (i.e throttle valve fully open at that RPM) or if that torque curve is given for a particular external load(i.e we can still increase the load and to keep the RPM constant we can still open up the throttle valve). I am guessing that the curve shows the maximum possible torque at a particular RPM but I am not sure.