Puts on my pedantic hat
Colloqually we typically say that a motor converts electricity to motion, while an engine runs on combustion. But is that accurate, and has that always been the case?
First we have to look at the history
An engine historically was anything that converted energy into mechanical motion. A motor is a machine which provides motive power. We can see that they have overlapping definitions.
Ironically, the first usages of the words were backwards to what we think of today. A motor (from the classical Latin movere or ‘to move’) was used for any mechanical device which produced propulsive motion – first in the industrial age with steel mills, steamships, and railways.
As it transpired through English, motor became used for anything that initiated or caused movement or change. A person could be a “motor” of a plot or a political party. By the end of the 19th century, a “motorcar” started to be used to describe a self-propelled train, and then later to describe the Duryea and Olds’ horseless carriages – aka, a motorcar.
Indeed, the first use of this was in a patent by Carl Benz for his strange 3-wheeled Motor Car, pictured above.
In 1885, the first motorbike or motorcycle was created – Daimler Reitwagen, pictured above.
So it’s really not possible to insist that a motor is only electric.
Then what is an Engine?
An engine (from the Latin ingenium: character, mental powers, talent or intellect) was first used to describe a person who effected change, then to things that effected change, then to things that effected movement. The first recorded usage of ‘engine’ in the contemporary sense was in 1853, and was – quite aptly for this conversation – for an electrical machine driven by a petroleum motor.
It was that usage becoming common that started to conflate the words.
Also, let’s not forget that “engine” can be used even more widely for anything that performs work or creates a product. Charles Babbage’s Difference Engine from 1820 was an automatic mechanical calculator designed to tabulate polynomial functions. Babbage’s Analytical Engine was a general purpose computer first described in 1837.
Today, they’re used pretty much interchangeably. Any major dictionary is going to list them as synonyms for each other. Remember, English is a living language defined by its usage.
So, technically, the Chevy Bolt EV has an engine, or an electrical motor. The Bolt’s service manual has no less than 2,600 references to the word “engine”, and more than 7,000 references to the word “motor”.