The reason for using big engines that have high torque when we can use a smaller, low torque engine and use a transmission to get the torque needed?

Question

Smaller engines should have better fuel consumption so this should be better, right?

In: Engineering

Answer 1

Transmission converts speed into torque. That is, a small engine would take a *long ass time* to do the same job as a larger one. Not much point in building a truck if it can only do 3km/h on that sewing machine motor, no?

Also, larger engines are usually more fuel efficient. The small engine uses less fuel each second but if you take all the fuel it needs to move the same thing the same distance, it’ll come up as more in total.