Why Is Cold Air Better?

[Saner]

This is for my Uni Project:

We all know that Colder, Denser, damper air is best for then enhine to run. But what is the science behind this that proves it?

I need to be able to say, the reason cold air is better is because... (i can't say it just is)

Anyone able to help or link me up?

Saner

 

[Matbrown]

The denser it is the more fuel it allows to be burnt.



Mat.

 

[John D]

Its more dense so there is more oxygen contained in a given area than the same of hot air. So an engine has to ingest less cold air to than it would hot air. More oxygen equals more power.

^^^Theres my effort

 

[Nik]

yep, air is more dense as temperature decreases, and more density means more oxygen molecules for a given volume of air. Oxygen is needed to burn the fuel, so more oxygen means more fuel burnt thus more energy released.

I think.... :S

 

[Saner]

What about the dampness? does the hydrogen also help with the reaction?

 

[stan*]

yup....the air molecules will also be closer together making for a more uniform mixture.

also reduced intake temps reduce the onset of detonation, and so more ign advance/boost pressure can be run.

 

[Nik]

One thing that people often overlook though is that although the engine might produce a bit more power, the air that the car is driving through is more dense which increases drag, so wether the car would be any quicker is debatable. This is a common problem with aircraft.

 

[Matbrown]

One thing that people often overlook though is that although the engine might produce a bit more power, the air that the car is driving through is more dense which increases drag, so wether the car would be any quicker is debatable. This is a common problem with aircraft.

And how often do we drive at 40,000ft? :rasp:



Mat.

 

[GazCB]

It's all about fuel/air ratio. You get the best power with a certain ratio. If you intake cold air, it is more dense and so you're effectively taking in more air quickly. If you're taking in more air then you can burn more fuel with it to maintain the air/fuel ratio. More fuel you burn, the more energy you produce.

 

[Nik]

And how often do we drive at 40,000ft? :rasp:
Mat.

Have you seen the height of a Trophy? :clown:

Nah, was just an example. Same problem though, just has a much bigger effect on a plane :rasp:

 

[Andy_J]

cool avatar Nik..

 

[stan*]

It's all about fuel/air ratio. You get the best power with a certain ratio. If you intake cold air, it is more dense and so you're effectively taking in more air quickly. If you're taking in more air then you can burn more fuel with it to maintain the air/fuel ratio. More fuel you burn, the more energy you produce.

yup...as has been said numerous times above!

that ratio is usally around lambda=0.88