I took college physics. I learned that power is unit work per unit time, which can be expressed as newton-meters per second. Torque is a cross-product quantifying rotational force accounting for a lever arm, which is expressed as newton-meters. I know that the distance in the measurement of torque is perpendicular to the direction of rotational motion whereas the distance in measuring power is parallel to the direction of motion, so these are not the same “meters” at all. But both of these involve a measure of force – more force means more power and it means more torque. However, when it comes to car engines, two engines can have the same horsepower but very different torque. Why do HP and torque not increase in lock-step? Is this just a matter of available gear ratios in the transmission? Or is there a way to build an engine deliberately to make torque vs. Deliberately to make horsepower independent of the transmission? Thanks!
In: 2
Ok, these answers are all saying the same thing so I think I understand.
Torque is applied force measured instantaneously, whereas horsepower requires the rapid and repetitive application of that force over time. So, big cylinders/pistons and long cranks can apply lots of torque, but to achieve high horsepower they need to apply it repetitively really quickly (i.e. at high RPM). This RPM is difficult to achieve with big heavy pistons. Smaller cylinder geometry achieves less torque but allows for higher RPM and therefore more horsepower even though the torque can be low.
Thank you everyone. I know this got a bunch of downvotes so my apologies if not appropriate for this subreddit. I appreciate everyone’s time and hopefully I can reciprocate by answering some questions here.
Latest Answers