little motor that could... no, doesn't sound right.

__________________
1985 190D 2.2l Sold-to Brother-in-law
1996 Mustang 3.8l -"thinks it's a sports car"
1988 Grand Wagoneer - Sold (good home)
1995 Grand Cherokee Ltd -"What was I thinking??!!"

My Engineering Professor, Mr. Merrick, in his very stoic New England accent, would tell us boys, that the terms could be used interchangeably, but in our lexicon today, an engine uses a fuel (or substance) that changes it's state (solid, liquid, gas, plasma), where as a motor uses energy that has an effect on another body ... i.e. an electric motor uses electron flow (current) through a wire which creates (right-hand rule!) a magnetic field which then creates a force (electro magnetic force - EMF for short) onto another body ... hence motion. Yes, I am simplifying this but I hope the point is understood.

Now, what about Rocket Motors? Well, if you follow Mr. Merrick's statement, he's wrong. My brother, being a Machinist, used to machine Rocket Propellant in a Motor Casing for those "special" agencies in the U.S. The Rocket Motor was a chemical-based motor that produced motion via the material changing states (remember ... solid to gas/plasma).

Engine and Motor can be used interchangeably ... depends where you are, and how you are using it. Both words are now in our lexicon.

__________________
1992 500E (Daily Driver)
2004 Porsche RUF 955 Dakara 550

Mr. Merrick would quiz us on engineering terms as well ...

Where did the term "Balls to the walls" come from?

Well we all know that it MEANS go as fast as one can, right?

To control (limit) the speed of an engine (let's say internal combustion type), a governor was used. The governor was a gizmo that had typically two balls (or bodies of mass) that would rotate around a shaft that was connected to the engine crankshaft (directly or indirectly). As the engine speed would increase, these balls would try to spin away from the governor shaft (centrifugal force) and then would reach a mechanical limit. The governor would then limit the speed of the engine.

Well, way back when, engines where in an Engine Room and if the balls (of the governor) where touching the walls, you've gone as fast as you can.

__________________
1992 500E (Daily Driver)
2004 Porsche RUF 955 Dakara 550

In the space propulsion business, "engine" refers to liquid fuel based systems, while "motor" refers to solid propellant based systems.

Good example!

Again ... the terms can be used interchangeably ... it just depends on what one is describing, and where (geographically).

__________________
1992 500E (Daily Driver)
2004 Porsche RUF 955 Dakara 550

Actually no, the terms are not interchangeable. Engine = liquid fuel, motor = solid fuel (although I suspect the actual difference to be more in line with what PEH mentioned, as opposed to being based on the propellant type used). For example, if someone talks about the space shuttle boosters, they will refer to them as "motors," not engines. OTOH, if they were talking about the propulsion systems mounted on the orbiter itself, they will use the term "engine," not motor.

Of course, to most normal people, this is all just semantics.

So what do all of you in North America who run yours on "gas" call them? In Oz most of us use liquid fuel, either petrol or diesel.

Sorry guys, couldn't resist that one. I know, for you "gas" is short for gasoline. We call it petrol. Cars here that run on gas (eg. most of our taxis, some buses and many privately owned vehicles that cover large annual distances) really do use gas. LPG or liquified petroleum gas is popular in Oz and CNG or compressed natural gas is also now in use.

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

That's probably the best answer.

I'm still hung-up on the expansion chamber as a definition. Can anybody name an engine that doesn't have an expansion chamber?

I guess a trebuchet is a seige engine. And you have search engines.

Okay, how about limiting to the industrial age?

Botnst

I think we just get used to pronouncing things a certain way.
NOBODY I know of EVER referrs to an electric motor as anything but a motor, but COULD you? Sure. Would everybody know what you mean? Sure. Would they correct you and say "NO NO, electric MOTOR, not electric ENGINE!" In about 2 second flat!
The internal combustion device located under the hood of your car (bonnet for you English guys), can be interchangeably called an engine OR a motor. The engineers at MB actually give them MOTOR numbers (M103 for example), but we can call them engines no problem, right? The same could work for any other type of energy producing device, but it isn't as widely accepted as an internal combustion engine. Does anybody correct anyone else if they refer to the internal combustion device in their car as an ENGINE or a MOTOR? I don't think so. We've become accustomed to using both terms in that case.
In reference to either solid or liquid fuel, how would that apply to what we call an electric motor? At one time, my thought was that a motor uses an already existing energy source, such as electricity, to produce motion, and an engine uses a FUEL to produce motion. But after enough thought about it, I think it is just what we get used to saying in regards to a particular type of device.

Gilly

Amen to that!

__________________
1992 500E (Daily Driver)
2004 Porsche RUF 955 Dakara 550

Gilly,

NO WAY !

Are there such things as starter engines?

Are there power window engines?

Does your heater have a blower engine?

Is there an engine in your refrigerator?

See what I mean?

P E H

Since it's obvious no one read that article I posted the link to:

ENGINE AND MOTOR
Two closely-related words investigated
On the rare occasions we encounter one, we refer to a steam locomotive as an engine, the same word that we give to the motive power of an aircraft. But all electrical devices are driven by motors. In Britain at least, one’s personal transport is a motor car (with compounds such as motor trade, motor vehicle and motor sport), even though it’s always powered by an engine. Small boats may have outboard motors and then are often called motor boats.
However, the propulsion device of a rocket can be called either a rocket motor or a rocket engine, and usage here seems not to have settled on one or the other. The IEEE Spectrum magazine for June 1998 (which Ron Jeffries has thoughtfully sent me) reports that the debate has been so intense, and yet so inconclusive, that some rocket scientist has coined the phrase whoosh generator as “the humorous, genderless, politically correct way to refer to the propulsion device in a hobby rocket, thus avoiding the great motor/engine debate”.
In everyday, non-technical usage the words have much the same meaning. But they have such clearly defined and fixed compounds (except in the rocket case) that they can’t be thought of as entirely interchangeable. The magazine article argues that the difference is that engines contain their own fuel or are part of a highly integrated engine-fuel system, whereas a motor draws on externally supplied energy. That’s the rule given in the Oxford English Dictionary, but on reflection it seems not wholly satisfactory. It doesn’t work for outboard motor or rocket motor for example. And it doesn’t explain why the two words should have been applied in this way. For that we have to look into their history.
Engine is from the Latin ingenium, which referred to one’s ability to create things, one’s native genius; it comes from a root meaning ‘create; beget’ from which we get words like genetic, and is also the source of ingenious and ingenuity (engineer derives from a related word). Its first meaning in English, from about the fourteenth century, was very much this one of mother wit or genius, a skill in devising things. It could also, by obvious extension, refer to the result of such ingenuity, a contrivance or device, particularly any mechanical apparatus. The term was very general; a sixteenth-century text directs that a person should be “put in the stocks or other such engine”; pulleys and their like were also engines (as in Swift’s Gulliver’s Travels of 1727: “With ropes and engines, I made a shift to turn it”). The British pub served its drink by means of beer engines, hand pumps which drew the brew up from casks in the cellar; blazes were extinguished with the help of fire engines, originally hand-operated pumps. In the 1670s one John Worlidge invented a machine for pulping apples in cidermaking; he termed his device the Ingenio, an obvious reference to the Latin original. Engine was commonly applied also to weapons of war, such as the siege engine and to devices such as snares for catching game (hence gin trap, where gin is a short form of engine that also turned up in compounds such as horse gin for a horse-powered windlass).
It was an obvious enough extension to apply the word to the new devices that created power through steam. At first these were static units designed to pump water from mines, hugely complicated even in their early Newcomen incarnations. The steam engine was such an important machine, being one of the crucial developments of the Industrial Revolution, in particular making possible deep mines, that engine soon came to apply almost exclusively to it (being replaced in most other cases by machine, a word that earlier had meant almost the same as engine). And that usage came to influence later extensions of it, as in petrol and diesel engines: no longer just a contrivance, but a system for producing propulsive power.
Incidentally, computer science has several terms that include engine, such as search engine, database engine and recognition engine. In all of them engine has the sense of a central part or kernel of a software application, hidden from the user, which does intensive ‘number-crunching’ work on data, only the results of which are made available. Charles Babbage named his Victorian mechanical computer the Analytical Engine, using the pre-Industrial-Revolution sense of the word. I would guess, in view of the almost iconic regard many computer scientists have for Babbage’s work, that the modern terms derive directly from this phrase.
Motor had quite different origins, coming from the Latin movere, ‘to move’. It was first employed in English in the sense of ‘instigator’, or something that causes motion, often in a figurative sense, as of God as being the cause of the motion of the heavens. Even by the nineteenth century, it was still applied generally to the idea of something that caused change, without necessarily implying a mechanical device; for example the Civil Engineering Journal in 1839 said “The true motor of the system would ... be the weight of the atmosphere”, in which motor here is an agent or force (a sense which is still current). It was also applied early in the same century to classes of muscles or nerves whose job was to cause parts of the body to move. Only in the 1850s did it begin to be applied to a device that employed some source of energy to create movement, being applied first to the electric motor and to hydraulic devices.
When the electric motor appeared, people saw a key difference between it and the steam engine. The latter had an obvious source of energy in its fuel; the source of energy of the former was less clear, being supplied mysteriously from a battery or generator by means of wires. Steam engines obviously consumed their fuel, but electrical and hydraulic devices extracted energy from some source without obviously consuming it. Perhaps this reminded people of the original sense of motor that referred to some intangible or spiritual force, and persuaded them to apply it to these new sources of power.
By the time that vehicles driven by internal combustion engines had begun to appear in any numbers, at the very end of the century, both words had become well established in common usage. The driving force was obviously an engine, which consumed fuel to provide motive power. But why the conveyance as a whole was termed a motor vehicle is less obvious. The mere fact of it moving was obviously not sufficient; that was hardly a new idea, after all. It may be that it was a more elegant word, and also helpfully distinguished the automobile as a system from anything that belched steam and soot, such as the early steam-driven road vehicles like the Stanley Steamer.
By the beginning of the twentieth century, the two words had moved together from very different origins, even though as we’ve seen, for historical reasons they were mostly employed in set compounds. But when new forms of propulsive device came along, analogy (or sometimes chance) decided which was to be applied in a particular case. Aeroplanes were obviously powered by engines, since the earliest ones were taken over directly from petrol engines of the kind that drove cars and lorries. Though there seems to be no clear evidence for the choice, perhaps outboard motor was so termed because it was a compact device that reminded its namers of electric motors.
The confusion between rocket engine and rocket motor is less obvious. By analogy with other devices that consume fuel, it ought to be an engine, but perhaps by the time it came to be named motor had become so close a synonym that either felt right.

__________________
past MB rides:
'68 220D
'68 220D(another one)
'67 230
'84 SD
Current rides:
'06 Lexus RX330
'93 Ford F-250
'96 Corvette
'99 Polaris 700 RMK sled
2011 Polaris Assault
'86 Yamaha TT350(good 'ol thumper)

No, do YOU see what I mean? Did you time yourself, I bet it was under 2 seconds. YES, I believe you could use those terms you gave, but it goes against every fiber of our being, because everybody KNOWS that an electrical device that produces motion is a MOTOR, but no one knows WHY. It's just how we learned to refer to them since we were young. I still maintain they are actually interchangeable with each other.

Gilly

Actually, there is such a thing as a starter engine on some big diesel engines.... Some people call them pony motors.

__________________
Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

Whew! after reading all that guess I'll take a spin on my enginecycle.........
William Rogers........