If you’re driving a hybrid Toyota in the St Louis area, you’ve probably heard quite a bit about fuel efficiency and gas mileage. You also know that your vehicle has great power and that you can take it anywhere you would take a standard gasoline powered car. Have you ever wondered about your engine’s power? I’m sure you’ve heard of horsepower, but we all know there aren’t horses under the hood of a hybrid Toyota!

Horsepower is an old term that originally applied to steam engines. When people first began to build engines that could push vehicles, their only basis for comparing power was the horse. Throughout human history, horses have been used for transport in many cultures, and it was natural to use the power of a horse to describe the output of an engine. While most people are far less familiar with horses these days, the name stuck and it’s how engine output is defined.

So, just how much power does a horse have? Horsepower was first defined in the early 1700s, when engines were built that could do the work of, say, two horses. This type of machine came to be known as a two horsepower engine. There were also complicated calculations regarding horses that worked in mills. The horses would walk and turn the stone that ground the grain. The weight and width of the stone and the number of revolutions in an hour became known as one unit of horsepower.

Over time, the horsepower unit that describes the engine in your hybrid Toyota underwent some changes. Different people measured the power of a horse differently, but in time the unit was standardized. There are differences between metric horsepower units and mechanical horsepower units, and even between the unit in different countries, but as long as you know the precise form used, you can figure out the output of the engine. We may no longer rely on horses, but the term is still used to describe engines to this day.

The next time you drive your hybrid Toyota, take a moment to think about how much transportation has changed. From horses to steam to gasoline to hybrids, we’ve come a long way.