Applied physics 101

[rpalmer]

I maintain that hp is heat. You say it's work. Work can't be done without energy and all energy is heat.

This is my position on Hp=heat.
Also the only porous of compression in an engine is to raise the cylinder temp. Compression tries to establish a proper environment for it's fuel. LP or propane needs high compression and diesel engines use relatively high compression to innight their fuel. As you compress air it's temp rises. So High compression = high (relative) temperature.

 

[thoffman]

When the heat goes up I get lazy.

 

[rpalmer]

Tom Hoffman,
The path of least resistance is "natures way".

 

[kide]

All right, I'm here (I schlumped my way through high school physics, but I've read a thing or two since).. I thought that hp was the application of a measured amount of force (applied energy measured in torque) for a given amount of time or...mumble mumble........mumble.

 

[sstanton]

Force=energy is what I had learned in school.

 

[rpalmer]

Kendell Ide,
Sounds right. I just remember learning that. Work takes energy; calories, joules, watts, horse power are all measurements of energy. Nothing works without energy. So to get mechanical torque you first need energy. In this case a controlled burn of fuel or gas. I'm sorry for always saying fuel. It is a habit. I am somewhat familiar with gas (all grades) diesel and propane for fuel of internal combustion and jet engines.

The efficiency of the burn, relative to the cycle the engine is in, leads to volumetric efficiency and more torque/hp. This being said. There is no energy/torque without heat.

BTW I looked for my printed material. Gone. Or I could give you btu/h , burn time ect for different fuels.

 

[rpalmer]

Scott Stanton
Force=energy is what I had learned in school

Yes it does. But it takes energy to make/transfer that force. All energy is heat. No heat.. no energy.. a body at rest.

 

[aschumacher]

The purpose of compression is to get the reaction of de-compression...some form of mechanical motion that can be used. <font size="-2">But compression does not necessarily mean "to raise cylinder temp". Burning fuel raises temp.</font>
Yes, heat is energy, the higher the heat, the more the energy. Depending on the fuel and design, hotter<font size="-2">burning fuel</font> is better.
So I guess heat does equal HP.

 

[sstanton]

Richard, I see. So a body in motion stays in motion, thus making heat/energy. Does that transfer into horsepower at some point? I'm just trying to learn from you guys. (I did horrible in school!)

 

[dtanner]

Hehe , well just got back from camping and the boys are at it again lol.In the high winds and rain the Diesel ram got 15 mpg . wow wind makes a big difference in fuel used in my D.


I have always used high test gas in all the small engines I own. I am old and most everything here is at least 10 yrs old.powersaw ect.I have never had a carb problem or cleaned. must be the good gas I think.


I also think that there is more energy in diesel that gas. I`am liking this info that i read here.
Keep them stirred up Richard ,,, LOL

 

[rpalmer]

Allen Schumacher,
But compression does not necessarily mean "to raise cylinder temp". Burning fuel raises temp.

Yes it does. When you compress air/atmosphere, you raise it's temperature. This is how a diesel engine gets combustion. The compression is high enough to ignite the fuel. (No spark plug)

Scott Stanton,
Richard, I see. So a body in motion stays in motion, thus making heat/energy. Does that transfer into horsepower at some point? I'm just trying to learn from you guys. (I did horrible in school!)

No that is perpetual motion. It does not exist. Yes. You have horsepower when you walk. But the number in HP has a lot of places. So it is broken down into calories. But you can convert it to any of the mentioned.

Donald Tanner,
Welcome back. Hope to see that loader on the 129 "in action" soon.

 

[jpatchett]

HP does not equal Heat.

The HP an engine creates is limited by what is being burned (combustion). The more hydrocarbon and oxidizer that can be burned, the more HP that can be created. Two major unwanted bi-products of combustion are heat and light. Heat reduces the efficiency of the combustion process (the creation of large quantities of gas, i.e. exhaust). The more heat that is dissipated, the less HP that is lost. Heat is not an object or substance, but something that is given up or absorbed (radiant, convection or conduction). Heat is simply another form of energy that can be measured ONLY in the terms of the affect it produces. Mechanical energy (HP) can be lost to heat , but not the opposite ( heat is not HP).

James Prescott Joule developed the relationship between thermal energy (heat) and mechanical energy (HP) in 1843. His experiment determined how much mechanical energy was needed to raise the temperature of 1 lb of water 1 degree F. How much work is needed to heat up a known mass of water. This energy to heat 1 lb of water is said to be 1 BTU and it took 778 ft lb of HP to do so. Joule stirred water with the use of falling weights to spin a stir and the friction between the water and stir created heat and that was absorbed by the water.

Power (HP) = work/time or ft lbs/sec or Joules/sec

HP is a force

Energy (heat) = BTU or Cal or Kcal= something lost or gained= related to a change in temperature

There is no work being done by heat over time, therfore it is not a force.

Jim

 

[dfrisk]

DONALD - You're CHEATING...Cummins get better MPG than My PSD... At least by a little. There's about 25% more BTU of heat energy in #2 diesel fuel than gasoline.

You guys have to remember an engine is an AIR PUMP. And HP is "CYLINDER PRESSURE exerted onto the Piston", Heat helps but after a certain point causes catastrophic failure! Have to get air in to burn before You can make HP. That's why BOOST is a WONDERFUL thing! But You can not exceeed the detonation point of the fuel You are burning. I think a guy by the name of LINGANFELTER said that, or maybe it was Smokey Eunick (sp).

I've had a couple posts typed out and hit "Delete" about burning fuel.

There's a website called "FAQabout gasoline" or something close. You Guys need to read up on that site. The most efficient engine ever made last time I checked that site was a HONDA F-1 engine from the 1980's.

A Kohler K-series doesn't even rank in the top 80% of the world of engines. The old FARMALL IHC 4-cylinder engines built in Rock Island, IL actually make awefully good torque per CID and hold that torque down to crazy LOW RPM. For instance, My Super H is supposed to run 1650 RPM, Peak torque is at 975 RPM at about 1-1/2+ #/ft per CID.

You read up on the BEST engine builders and anything above 1 HP/CID and 1 #/ft of torque per CID is very good. And IHC was getting That with 70 octane gasoline back in the 1940's & 1950's but just wasn't making the HP because of the VERY low RPM.

You Guys keep arguing.....

 

[rpalmer]

Jim Patchett,
The more hydrocarbon and oxidizer that can be burned, the more HP that can be created.
If by oxidizer you mean air I agree. And without a burn (heat)how much hp will you develop?

Two major unwanted bi-products of combustion are heat and light

The unwanted byproduct of combustion is water.
Heat is not an object or substance, but something that is given up or absorbed (radiant, convection or conduction). Heat is simply another form of energy that can be measured ONLY in the terms of the affect it produces. Mechanical energy (HP) can be lost to heat , but not the opposite ( heat is not HP).

Given up from what? The sun gives heat. Where does it come from? Mechanical energy or any other gets lost to heat often in the form of friction. This is the reason you (one) can not have a perpetual motion machine.

All energy is heat. All heat is energy. Be it potential or conetic.


Maybe this will help in understanding.

joules 9.48E-04 Btu
joules 10000000 ergs
joules 0.7376 foot-pounds
joules 0.0002389 kg-calories
joules 0.102 kg-metres
joules 0.0002778 watt-hrs

746 watts equals 1 horsepower

horsepower 42.44 Btu/min
horsepower 33000 foot-lbs/min
horsepower 550 foot-lbs/sec
horsepower (metric) 0.9863 horsepower
horsepower 10.68 kg-calories/min
horsepower 0.7457 kilowatts
horsepower (boiler) 33479 Btu/hr
horsepower (boiler) 9809.5 watts
horsepower (metric) 735.4988 watts
horsepower (electric) 746 watts
horsepower see tables cc and cu.in. (approx)
horsepower (UK) 745.7 watts
horsepower (water) 746.043 watts

horsepower-hrs 2547 Btu
horsepower-hrs 2.68E+13 ergs
horsepower-hrs 1980000 foot-lbs
horsepower-hrs 641190 gram-calories
horsepower-hrs 2684000 joules
horsepower-hrs 641.1 kg-calories
horsepower-hrs 273700 kg-metres
horsepower-hrs 0.7457 kilowatt-hrs

One calorie is equal to:

International System (SI)
megajoule 4.1868 *10-06
kilojoule 0.0041868
joule 4.1868

Dennis,
I was taught that the most efficient engine was the steam engine. BTW... I believe it.

 

[mgonitzke]

Oh my...I'm gonna dig out my Thermodynamics book and debunk a few things you guys are saying...when I get time.

 

[dross]

Horse power is an accual measurment. It's so many pounds over a given distance. I think in one minute. Didn't mean to get so technical, It's what one horse could do. Today the dynos use applied force for thier torque numbers, then use RPM to covert the torque to hp.
When combustion happens in a cylinder you try to time the "spike" in pressure really close to but after top dead center. this transfers the highest mechanical advantage into crankshaft rotation. You have to realize by the time the crank spins 30 degrees from TDC, the piston moveing away from the bottom of the head, You lose preassure. Higher octain fuel is less prone to preignition (ping) and allows the higher compression (more stored energy), it's really slower burning. So to put that spike at just after TDC you have to make the plug fire sooner. Comments?

 

[jpatchett]

Richard,

I understand your perspective of thought, but your not understanding HP is work over time and heat is a form of energy.

Water is a by-product in a rocket engine, hydrogen and oxygen, but very limited in a gas engine, not much hydrogen in the air we or an engine breaths (sea level to 10,000ft)

The sun creates heat through Nuclear Fusion, motion at the molecular level, yes friction by simple terms.

Heat is a bi-product when work is done.

Your list of HP equivalents are the forms of HP and the work/time relationship. There is boiler, electrical, metric and hydraulic, all are work being done over some period of time, hrs, min, sec, etc.

Heat is transfer of energy from system or substance to another, or related to motion/vibration. If I hold an ice cube in my hand it melts, because of the transfer of heat from my hand to the ice. What HP is being used here? No work is being done, no motion no vibration, no friction. Some heat in my hand was given up to the ice, and no work was done, no HP needed.

Our bodies consume and store energy and we know this to be expressed in units called calories. For us to loose calories we must do work, exercise, everyday life given a fast metabolism. The point being your body must be doing something (work) to loss calories and thus generating heat in the process of doing work.

 

[rpalmer]

Dave Ross,

I am in total agreeance (sp) with you.
Higher octain fuel is less prone to preignition (ping)
This being relative to the ignition timing.

Jim Patchett,
Water is produced by all internal combustion engines. Why does your exhaust rust out?

Heat is a bi-product when work is done
Right. No perpetual motion machines.
Your list of HP equivalents are the forms of HP and the work/time relationship.
Right. And they all require energy to happen. And that comes from heat.
If no work was applied to the ice it would remain a solid. A body at rest will stay that way until an equal and opposite force acts on it.
Calories convert to joules and they to watts and they to horsepower. These are not my rules. Well not of my making.

 

[bbrigham]

 

[mgonitzke]

Power is the time derivative of WORK, meaning it is the RATE of ENERGY TRANSFER by WORK, which is expressed in terms of any units for energy and time.

Richard-

Heat transfer is energy transfer. Jim is correct; the ice cube will melt because of heat being transferred to it from your hands, with no work done. All energy is not heat...you're talking about thermal energy. There is also kinetic, potential, gravitational, sound, electromagnetic, etc.

Jim-

There isn't much hydrogen in the atmosphere, but don't forget that the fuels being burned are hyrdocarbons, which are compounds composed mostly of carbon and hydrogen. That's where the water is coming from.