
Louie T. answered 12/05/20
Mechanical Engineer Specializing in Solidworks
Hi Jackson! Since this is a purely hypothetical problem, we can discount both the efficiency and the friction of the gears and engines which makes our job a lot easier. If you are looking to go from a lower torque to a higher torque, the gear ratio will always be a bigger gear connected to the engine shaft and a smaller gear connected to the output shaft. Since both engines are geared to the highest possible torque, it would mean that they have the same gear ratios. This gear ratio can be thought about as as infinitely big gear attached to the engine shaft and an infinitely small gear attached to the output shaft. If you have learned about the concept of different "sizes" of infinity, then you can think about it like that. You have
Big_Engine_Output_Torque = (Engine_Big_Input_Torque * Infinite_Gear_Ratio)
as the torque of the initially higher torqued engine, and you have
Small_Engine_Output_Torque = (Engine_Small_Torque * Infinite_Gear_Ratio)
as the torque of the initially lower torqued engine. If the original ratio of the bigger input torque over the smaller input torque was >1, then the new ratio of the bigger output torque over the smaller output torque will be the same (>1) because you can cancel the gear ratio term out of the top and the bottom. You can see that no matter how much you crank the gear ratio up, the engine with the higher initial torque will always produce a higher output torque.