how do dynos work?

[commsirac]

Really? So tell me what are your qualifications? What are you qualified in? What do you do for a living?

I figure that you are neither a mechanic or mechanical engineer, because if you were I don't think that you would be explaining the combustion process as explosions. Come on champ tell us all about it. I am waiting for my hiding, (Although generally I prefer a light spanking ).

So I take it from that response you didnt do high school physics?

What are my qualifications and profession? more than enough to comment on the differences between torque and power.

Sorry, I dont reveal personal information on a public forum for several reasons, which i wont go into.
Regardless, If I was able to tell you what my qualifications were and what I did for a living, you probably wouldnt believe me.....then you'd be asking for proof, where would it end, Id have to post a copy of the transcripts for my uni results or pictures of my degrees? Then whose name appears on the degree, is it really me, then Id need my passport photo....no thanks.
The reality is anyone can claim to be anyone on the internet, it is more important to look at what they say.

 

[Not_An_Abba_Fan]

Energy and power are two different things though. We aren't disputing the transfer of energy, the point I was trying to get across is that the process of calculating the 'power' output of an engine is the measuring of it's torque then using a formula to work out it's 'power'. James Watt originally wanted to quantify a steam engine's ability to do work by comparing it to the rate at which a horse could move a weight over a distance in a set time. The term 'Horsepower' is an approximation, as no two horses could do the exact same amount of work in a given time. Horsepower was used because it was what was understood by the people at the time.

While power does exist, I still contend that an engine doesn't 'make power' it makes torque. The engines ability to make usable torque in certain rev ranges is converted to kW or HP by a formula. If the engine were to 'make power', then why isn't there a device to measure it?

 

[vt748]

Yeh mate I did high school physics. Ha Ha a long time ago. Getting a bit old now I am afraid. But I always remember my first physics lecture at university when the lecturer told us to forget everything we learnt about physics at high school, because basically it's the baby version, to give you a taste so to speak. But i am sure you already know this.

Since then I have among other things built engines professionally for 8 years. I obviously am not in your league as any engine I built only produced torque. The power always had to be calculated.

I have also have tested engines on engine dyno's for 2 years.

Believe or not, couldn't care less, you obviously do alot of research and are confident in your own beliefs. Maybe next time you can do a bit of research on the explosions that happen in YOUR engine that produces POWER. :thumbsup:

 

[commsirac]

post removed....when you keep banging your head against a brick wall, sometimes its best to stop.

 

[greenfoam]

Well so long as the torque happens as high in the rev range as possible I don't care how it's messured because that's how you go realllly fast, you can probably make a 10 second 1/4 mile in a V6 commodore with it's stock 300 nm of torque (if that torque happened at 12,000 rpm) that's why someone smart invented gears!, Power is everything

 

[commsirac]

post removed .....futile

 

[vt748]

Commsirac, mate you just waffle on and on. The original posters question was how does a dyno work. Now we have explanations from you on how thermometers work, how thermocouples work,how much energy is in a bowl of cornflakes, blah blah blah.....You seem to just want to quote what you learnt in your high school Physics class.

Basically the only thing that has been needed to be discussed is torque, rpm, and power. You contend that the engine produces power and torque, I reckon the only thing that an engine produces is torque. I think I will just agree to disagree with you.

BTW I was never confused by you using the term "explosion", it just gave me an insight into how much you really now about engines!

 

[commsirac]

You are right vt748, it is pointless me waffling on when the people such as yourself and NAAF, whom I am hoping to convince otherwise, have had these views for perhaps along time and nothing will convince you otherwise.
Hopefully what I have posted is not wasted on those with open minds.
You are not going to tell me that you worked on a dyno that only gave your torque readings, surely not? There is no magic formula that engineers can simply plug just a torque value to get a power figure, or perhaps you can produce one.
The "magic" formula I believe you are talking about is:
(power(kw) = rpm x torque(Nm)/9549)
Perhaps the dyno you worked on provided torque and power readings? the power reading could only be arrived at if the dyno was measuring its rotational speed, which they all do.....

Torque wrenches produce torque......they are not engines

 

[Not_An_Abba_Fan]

Torque wrenches meausure torque actually....The force of your arm pulling or pushing the wrench is what is producing the torque...

 

[commsirac]

Torque wrenches meausure torque actually....The force of your arm pulling or pushing the wrench is what is producing the torque...

If we extend your logi: if dynos only measure torque and torque wrenches measure torque, then a dyno and a torque wrench are the same thing?

For goodness sake, torque wrenches are machines/levers that are force multipliers(we use them to tighten bolts etc) and they have a scale on them to measure how much torque they are producing.
They dont have to be pushed on by humans, we can just hang weights off them to create the torque if you like.....but I agree by itself a torque wrench wont do much, I had given up on making sure what I wrote was word perfect.....so you can win some points there.......
However, the simple point, which has been explained to you(fifty times ^?), is it is very easy to produce massive torques, ie standing on the end of a metre spanner produces more torque than any production car v8, which archimedes worked out just a little while ago.

Simply most dynos as we know them, measure the torque and the rpm produced at the rollers.........which combined together these two quantities gives us power! Just like we combine the voltage and current that goes through a toaster to give us a power rating.:bang: