Torque of diesel vs Petrol

[artme]

Can some knowing forumite explain why a diesel engine prodces so much torque compared to a petrol engine and yet produces less power??

Thanx in advance.

[Avery]

Basically because diesel engines have a longer piston stroke, therefore a longer conrod and exert more leverage on a bigger diameter crank.

More leverage = more torque.

A petrol engine with a long stroke delivers more torque than a petrol engine with a short stroke.

Short stroke engines turn at higher RPM and deliver more power and are probably easier to drive, or at least they were with conventional transmissions.

Diesel also converts to more energy than petrol.


Of course, I could be totally wrong

[Scott]

Does this help?

-Scott.

[Scott]

And got this out of one of my books:

Horsepower provides highway passing power when your engine is revving hard, allowing you to accelerate at high speeds, while torque gives you low-end power and the ability to move quickly after stopping. In other words, torque lets you do the work, but horsepower lets you do the work quickly.

Think I'm going off on a tangent here...

[artme]

Thank you gents! It was much as I expected.

It will be interesting to see how the new range of Mazda engines perform. Both have a compression ratio of about 14:1 (( as I have read somewhere).

This is quite high for a petrol engine but apparently will give a cleaner brn and deliver more grunt. For a diesel this is quite a low compression ration but wll allow the diesel fuel to burn mre slowly ( diesel burns more slowly than petrol ) and completely and therefore more cleanly.

All very interesting stuphph

[BobL]

Can some knowing forumite explain why a diesel engine prodces so much torque compared to a petrol engine and yet produces less power??

Firstly torque and HP are not a single quantity for any engine but vary dramatically with RPM so your question should perhaps be ". . . why a diesel engine prodces so much maximum torque compared to a petrol engine and yet produces less maximum power

This web page answers your question far better than I can.
http://www.vettenet.org/torquehp.html

[Ozkaban]

That's neatly explained in your link, Bob.

I've always remembered it by "Torque is twisting force, hp/kw is the rate at which it is put to work"

Cheers,
Dave

[BobL]

That's neatly explained in your link, Bob.

I've always remembered it by "Torque is twisting force, hp/kw is the rate at which it is put to work"

Well put!

[Christopha]

Doesn't matter coz only girlymen drive petrol powered things, and real men drive diesel powered utes!

Hmm... must myself one again.....Swish!

[jimbur]

Doesn't matter coz only girlymen drive petrol powered things, and real men drive diesel powered utes!

Hmm... must myself one again.....Swish!

Only since they changed from steam
Cheers,
Jim

[AlexS]

I've always remembered it by "Torque is twisting force, hp/kw is the rate at which it is put to work"

... and the closer the couple, the less the torque.

[wheelinround]

Doesn't matter coz only girlymen drive petrol powered things, and real men drive diesel powered utes!

Hmm... must myself one again.....Swish!

Says he who rides a diesel powered motor bike.

[wheelinround]

All this talk about torque its a matter of a pinion and its differential surface traction if you don't grasp it it'll leave you smoking.

[3RU]

All this talk about torque its a matter of a pinion and its differential surface traction if you don't grasp it it'll leave you smoking.

.......or going nowhere.

Great read guys

[artme]

Thanks Bob!, A good read. Must read again so it sinks even deeper into the realms of cognitive functtion.

Diesel contains more enery per litre or per kilo than petrol?? Which is it??