Engine Performance Parameters

[hayai32]

Hey all,

I've recently done a practical investigating the variation of performance parameters of a simple single cylinder 4-stroke engine at varying engine speeds and have a few questions that I can't fully explain.

What are the implications of a high or low "Volumetric Efficiency"?

What would cause a reduction in or increase in "Volumetric Efficiency"?

What causes "Brake Thermal Efficiency" to decrease at high and low engine speeds?

What are the implications of a high or low "Equivalence ratio"?

Any help would be greatly appreciated.

Thank you in advance.

Col.

[heller44]

Is this a school assignment?

[paulr33]

howstuffworks.com

will tell you all you need to know

[hayai32]

Hsw.com is not really helpful in my case, bit too general.

I'm fishing for very specific explanations.

Cheers anyway though.

[fr0st]

http://en.wikipedia.org/wiki/Car_engines

http://en.wikipedia.org/wiki/Volumetric_efficiency

http://en.wikipedia.org/wiki/Equivalence_r...uivalence_ratio

[dead32]

What are the implications of a high or low "Volumetric Efficiency"?

What would cause a reduction in or increase in "Volumetric Efficiency"?

What causes "Brake Thermal Efficiency" to decrease at high and low engine speeds?

What are the implications of a high or low "Equivalence ratio"?

Any help would be greatly appreciated.

Thank you in advance.

Col.

1. a high volumetric efficiency = more bang for your buck. the higher it is the better the car will go.

2. more boost would cause a increase and the reverse for a reduction.

3. airflow causes them to cool. less friction on the pad to disc allows them to cool. very simple

equivalence ratio ive never heard of lol

[rob82]

Equivalence ratio is basically what manufactures call lambda. Eqv Ratio of 1 means lambda 1 or 14.64:1 AFR. Eqv ratio of 0.82 is aprroximately 12:1 AFR. High Eqv ratio means leaner - less fuel and low eqv ratio means richer - more fuel.

Volumetric efficency is usually highest at peak power and can be infulence by alot of things- camshaft, head design, combustion chamber shape, compression, forced induction etc etc etc.

[dead32]

yea basicaly the more air u can fit into the same amount of room. hence the reason forced induction actualy works and works so well.

[Trust33]

1.low gives a slower outcome.High gives a quicker outcome.

2.Hot,cold.Restriction,no restirctions.

3.Brakes heat is a result of friction as allready stated.And various metallic non metallic compunds will give different thermal readings.So how much punishment it can stand up to,is directly related to the thermal properties of what it is made up of.Dont forget cold air has a higher O2 density hot lower.tho hot air can still be used to cool things down it has to be propelled to do so allong with a few other variables.(velocity)Murphys law really einstien.

You came to a car forum why! to ask these questions?