the dumb thing is, i know what torque is, (coz i studied it in science) and how it creates horse power. i just cant see how it relates to an engine.

 

i know the easyest way of explaining torque is using a bicycle as an example, its been used on many web-sites. If the distance from the center pivot of the pedal to the center of the drive sprocket on the bicycle is 1 foot. and you stand on the pedal with all your weight, say 150 lbs. You are generating 150 lb.ft. of torque, for as long as you stay standing on the pedal. if u maintain the 150 lbs of force on the pedals at 4 rpm (one revolution every 15 seconds). u will be making .144BHP (RPM x torque lb.ft. divided by 5252 = BHP)

so horsepower is the result of torque at a given rpm. doubling the torque at a given rpm doubles the power (hp). Or doubling the rpm with the same torque doubles the power (hp).

 

i just dont see how torque is created/calculated in an engine. this is probably due to my lack of knowledge on how an engine really works.

 

do they use hyperthetical weights when working it out?

 

I.E. if we put a 300 lb weight on the end on this engines crankshaft, and it can revolve this weight 9000 RPM. this engine is producing 514BHP @ 9000 RPM????

 

i just dont get how they work it out. sum1 explain please!

Knowing that torque is a force of turning motion and an engine converts linear to rotational the torque is used to spin the crank

 

When the piston is at the top of its stroke the torque is none, as the piston is forced down the torque is turning the crank.

 

Examples I had when i did mechanical science at college was of steam engines transfering cylindrical to linear movement.

 

The weight bit, not sure where you were going with that but its based on the force created by the bang forcing the piston down!!

Edited July 29, 200420 yr by Mike RS2300

so does that mean compression ratio is the key factor??

 

and why turdo diesel engines have high touque ratings???

this lot might help:

 

 

How do you convert engine torque to horsepower?

 

Why do big diesel engines and race car engines have such different horsepower ratings?

 

How Force, Power, Torque and Energy Work

 

 

lets me know if it helps

giving a brainless Cnut like me a haedache

 

power and torque mean absolutle nothing except good pub talk.

 

1/4 mile times speak....

giving a brainless Cnut like me a haedache

 

power and torque mean absolutle nothing except good pub talk.

 

1/4 mile times speak....

or pub torque

giving a brainless Cnut like me a haedache

 

power and torque mean absolutle nothing except good pub talk.

 

1/4 mile times speak....

LMAO

 

i'm beginning to agree!

that info did kinda help.

 

so basically. the bigger the combustion bang, the more torque your engine will have.

 

thats what was confusing me, because i didnt know where the "weight" was coming from to give the lb per ft number.

 

coz in the bike example, the weight is coming from the person standing on the pedal and turning it.

in an engine i take it the weight comes from the pressure caused in the combustion process, forcing the piston to move, thuss turning the crank.