a situation the electric pump speed can be measured by a speed sensor 74 with the signal from speed sensor 74 provided to ecu 68 speed sensor may be a hall effect sensor proximate a toothed wheel rotating with electric pump 51 or any other speed sensor known to one skilled in the art according to an embodiment of the present disclosure operating parameters associated with electric pump 51 can be used to infer flow rate and pressure in the fluid circuit such inferred values can be determined whether mechanical pump 22 is operated or not when both electric pump 51 and mechanical pump 22 are operated the flow rate provided by mechanical pump 22 is estimated because mechanical pump 22 is a positive displacement pump its estimated output flow rate is based on its rotational speed mechanical pump 22 is driven by and coupled to engine 14 via a gear set 24 and 26 typically engine 14 is provided with a toothed wheel 70 and a hall effect sensor 72 sensor 72 provides a signal to ecu 68 from which engine speed is computed and mechanical pump speed can be computed based on engine speed and a gear ratio of gears 24 and 26 electric pump 51 in one embodiment is driven by an ac motor the pump is controlled by applying a.