Car Chat

[Soup DeVille]

The term is from old French.  "Engine", from ingenium, is a contrivance.  Same meaning behind "search engine".

As is an electric motor.

[MX793]

As is an electric motor.

Sure, if you want to take that definition.  But in actual use, nobody refers to electric motors as "engines".  Google "electric engine" and you'll get only information on electric motors.

And fuel cells, like batteries, are neither engines nor motors.

[Soup DeVille]

Sure, if you want to take that definition.  But in actual use, nobody refers to electric motors as "engines".  Google "electric engine" and you'll get only information on electric motors.

And fuel cells, like batteries, are neither engines nor motors.

They're engines, not motors. It goes one way, not both ways. Electric motors are engines. All engines are not motors.

Look, I was taught the same thing in thermo as you. It was useful for the class, but in general, its just not an accurate distinction. For Ward's purposes, it makes much more sense to call it a "10 best engines list" than it does "a list of the ten best ways of moving a car or truck including, but not limited to, heat engines, electric motors, and any other effective contrivances."

[MX793]

They're engines, not motors. It goes one way, not both ways. Electric motors are engines. All engines are not motors.

Look, I was taught the same thing in thermo as you. It was useful for the class, but in general, its just not an accurate distinction. For Ward's purposes, it makes much more sense to call it a "10 best engines list" than it does "a list of the ten best ways of moving a car or truck including, but not limited to, heat engines, electric motors, and any other effective contrivances."

What I was suggesting was that Wards call their list "10 Best Motors" or "10 Best Powerplants".

A fuel cell is not a machine.  It's essentially an air-breathing battery, converting chemical potential energy into electricity via chemical reaction.  If you want to go archaic and call a fuel cell an "engine" because it's a contrivance, then we can start calling refrigerators, computers, TVs, and cell phones "engines" too.

[Soup DeVille]

What I was suggesting was that Wards call their list "10 Best Motors" or "10 Best Powerplants".

A fuel cell is not a machine.  It's essentially an air-breathing battery, converting chemical potential energy into electricity via chemical reaction.  If you want to go archaic and call a fuel cell an "engine" because it's a contrivance, then we can start calling refrigerators, computers, TVs, and cell phones "engines" too.

Yes, a fuel cell most definitely is a machine, but lets work with one word at a time.

When you read "10 best engines in this context," do you expect to find low speed diesel generators, jet turbines, or 2-cycle chainsaw engines on the list even though those fit every definition of engine you want to use? No, you're expecting to find machines that power cars and light trucks for personal/consumer use. That doesn't have to be spelled out, because you approached that definition as a reasonable person looking to understand what was being said, rather than an opportunity to be as pedantic as possible.

[giant_mtb]

Oh god.

[shp4man]

I've always thought the "engine" was the main power source of any given transportation device and a "motor"was a secondary device, like  fan motor or wiper motor.
This may not be the strict definition, but it's common usage.

[MX793]

Yes, a fuel cell most definitely is a machine, but lets work with one word at a time.

There is no definition under which a fuel cell is a machine.  It has no moving parts.  It does not operate by, produce, impart, or convert mechanical force or power.  It is no more a machine than a lead-acid battery or a solar cell.

[Soup DeVille]

I've always thought the "engine" was the main power source of any given transportation device and a "motor"was a secondary device, like  fan motor or wiper motor.
This may not be the strict definition, but it's common usage.

I think if you go back far enough, an engine is Almost anything that converts energy from one form to another, and a motor is an engine that provides motion (hence motor-car, a term that goes back to Duryea and the Mercedes-Simplex in the 19th century).

[Soup DeVille]

There is no definition under which a fuel cell is a machine.  It has no moving parts.  It does not operate by, produce, impart, or convert mechanical force or power.  It is no more a machine than a lead-acid battery or a solar cell.

Why would one double down after all this?

( Oxford English Dictionary) 1.2technical Any device that transmits a force or directs its application

No requirement anywhere that that force needs to be mechanical in nature. Batteries are machines that store energy for transfer. Its not complicated. Moving parts are not required.

[shp4man]

In common usage, engine and motor can both be used to describe the device that actually moves the vehicle.
As in " This Mustang has the 5.0 motor".
But won't interchange with secondary devices.
As in "Damn it, it's raining and the sunroof engine won't work".

[MX793]

Why would one double down after all this?

( Oxford English Dictionary) 1.2technical Any device that transmits a force or directs its application

No requirement anywhere that that force needs to be mechanical in nature. Batteries are machines that store energy for transfer. Its not complicated. Moving parts are not required.

And what is the definition of Force?

What vector force (or torque) is created by a fuel cell (or a battery, for that matter)?  How many lbs or ft-lbs are created?

[Soup DeVille]

And what is the definition of Force?

What vector force (or torque) is created by a fuel cell (or a battery, for that matter)?  How many lbs or ft-lbs are created?

Transmits or directs; not creates. That would require a god or some sort of deity.

Electrical force, as measured in Coulombs of charge. A coulomb is 1 Amp-second. An Amp is the amount of current that produces a force of 2x10^-7 NEWTONS between 2 wires a meter apart.

Do we need to go over our basics again?

[shp4man]

Sounds like Tesla (not the car company, the scientist) was involved in that stuff. 

[Soup DeVille]

Sounds like Tesla (not the car company, the scientist) was involved in that stuff. 

He gets a unit too. 1 Tesla= 1 Weber/square meter of electromagnetic flux.

[CaminoRacer]

I don't care about a list of electric motors, so I don't care about fuel cells. It's not like gas engines that have character

[Soup DeVille]

I don't care about a list of electric motors, so I don't care about fuel cells. It's not like gas engines that have character

That's fair to a point, but some of the guys that are into hand-winding their own motors for R/C cars would disagree.

Maybe we think they're without character because we're unfamiliar with them being used in cars.

[Galaxy]

I don't care about a list of electric motors, so I don't care about fuel cells. It's not like gas engines that have character

A horse has more character then any combustion engine, but people in general deemed the horseless carriage to be superior.

[Soup DeVille]

A horse has more character then any combustion engine, but people in general deemed the horseless carriage to be superior.

Sure, if "having the shakiest grip on sanity" is character.

[MX793]

Transmits or directs; not creates. That would require a god or some sort of deity.

Electrical force, as measured in Coulombs of charge. A coulomb is 1 Amp-second. An Amp is the amount of current that produces a force of 2x10^-7 NEWTONS between 2 wires a meter apart.

Do we need to go over our basics again?

Allow me to rephrase:  What vector force or torque is input, output, or transmitted by a fuel cell?  To be a machine, it either needs to take mechanical work in to perform some task (a generator converts mechanical work to electricity) or take some other form of energy and convert that mechanical work (an engine or motor), or transmit work (like a gearbox).  A fuel cell, like a battery, has no mechanical inputs or outputs.  They do not take force in, they do not put force out.  They are not machines.

And neither the coulomb nor the ampere are units of force.  Neither of these is a vector quantity (which is part of the inherent definition of force).  That amperes may be measured by measuring the electromagnetic force that an electrical current through a wire can generate does not make it a force itself.  We similarly can determine mass by measuring the weight of an object, but mass is not force even though weight is.

[shp4man]

My sister loved horses, so i got to know them. Here's the real difference- horses can think, avoid obstacles, catch or cut that steer out, all by itself, no human input. Let's see an autonomous car cut a steer out of the herd. 

[MX793]

My sister loved horses, so i got to know them. Here's the real difference- horses can think, avoid obstacles, catch or cut that steer out, all by itself, no human input. Let's see an autonomous car cut a steer out of the herd. 

Given their tendency to plow into parked fire trucks and emergency vehicles, I'm sure a Tesla on autopilot would have little trouble cutting any steer in its path out of the herd.  Car probably wouldn't fair too well, though.

[shp4man]

Given their tendency to plow into parked fire trucks and emergency vehicles, I'm sure a Tesla on autopilot would have little trouble cutting any steer in its path out of the herd.  Car probably wouldn't fair too well, though.

They get spooked by some unusual things, or noises, or high commotion. It's a horse personality thing.

[Soup DeVille]

Allow me to rephrase:  What vector force or torque is input, output, or transmitted by a fuel cell?  To be a machine, it either needs to take mechanical work in to perform some task (a generator converts mechanical work to electricity) or take some other form of energy and convert that mechanical work (an engine or motor), or transmit work (like a gearbox).  A fuel cell, like a battery, has no mechanical inputs or outputs.  They do not take force in, they do not put force out.  They are not machines.

And neither the coulomb nor the ampere are units of force.  Neither of these is a vector quantity (which is part of the inherent definition of force).  That amperes may be measured by measuring the electromagnetic force that an electrical current through a wire can generate does not make it a force itself.  We similarly can determine mass by measuring the weight of an object, but mass is not force even though weight is.

You keep changing you definitions, it would be best if you found one to defend.

And that is not a way to measure an amp; it is the definition of an amp. Electromagnetism is really one of the basic irreducable four forces we know about. Physical movement of objects is really a combination of of gravity, electromagnetism, and the strong and the weak subatomic forces. Coulombs are electromagnetism; electromagnetism is a force in a way that is fundamentally more real than anything you can directly observe; and I gave you a way to observe that force as a vector quantity.

Correction; an amp is a force. Coulombs are potential energy.

[Soup DeVille]

If you need to visualize it a different way,  a coulomb is the sum of forces created by a whole buttload of electrons being repelled by each other and trying to move to a lower-electron populated area. Tiny masses waiting to accelerate themselves to a better neighborhood.

[MX793]

Correction; an amp is a force. Coulombs are potential energy.

I have not changed my definition.  Several posts up: 

It does not operate by, produce, impart, or convert mechanical force or power.

This is wholly consistent with everything I've said about fuel cells not being machines.

If you need to visualize it a different way,  a coulomb is the sum of forces created by a whole buttload of electrons being repelled by each other and trying to move to a lower-electron populated area. Tiny masses waiting to accelerate themselves to a better neighborhood.

If the amp is a force, then voltage is a unit of velocity.  What's the conversion factor to go from volts to miles per hour?

Current may be (sort of) analogous to force in electricity, but it is not a force.  A force, by definition, is a vector quantity.  Electrical current is a scalar.  There is no direct conversion from force units like pounds or Newtons to amps.  They aren't the same thing.

Fuel cells are an electro-chemical device.  They are not machines.  There is no definition of machine by which they fit because they do not operate by the input of mechanical force (or torque) nor do they directly output mechanical force (or torque).

[Soup DeVille]

An Amp is a force. You can learn more about that if you wish (hint; convert Horsepower to kW) but I've no further wish to repeat myself. You like to call things what you want, and that's cool.

[MX793]

An Amp is a force. You can learn more about that if you wish (hint; convert Horsepower to kW) but I've no further wish to repeat myself. You like to call things what you want, and that's cool.

Horsepower and kW are both power.  Both can be expressed in units of mass x length^2 / time^3.  All units of force can be expressed a mass x length / time^2.  The ampere cannot be expressed as such.  It's also a scalar quantity.  Forces are vectors.  It's not a force.  That's not me calling things what I like or taking a particular interpretation (like engine vs motor).  That's basic physics.  It's not debateable.

[Soup DeVille]

Horsepower and kW are both power.  Both can be expressed in units of mass x length^2 / time^3.  All units of force can be expressed a mass x length / time^2.  The ampere cannot be expressed as such.  It's also a scalar quantity.  Forces are vectors.  It's not a force.

Oh geeze man. Will you just look up the definitions of these things. What's the SI definition of a watt?

[Soup DeVille]

Try thinking about it this way. I'm over complicating it.

You say that a battery is not a machine because it does not input, convert, or transmit a force.

Yet a motor is, for the exact same reasons. What's driving the motor then?  If a battery retains a certain amount of energy (as they are of course rated in kWh), how does it transmit that power without there also being a corresponding force? Can you have power without force? Of course not.