The Thermodynamics of the combustion engine

[drakkie]

As you might all know, i now study for Automotive engineer. This is the stuff we did at the subject called "Engines". My Technical english is not upto the standard native english may have so i need to use a dictonairy quite often. So please, correct me if I am wrong. I have holidays this week,so i will try and do as much as possible of this. This is the first page of the pretty long essay i am writing especially for you guys !!! i reckon this is page 1 out of 25/30 Lets hope you guys enjoy it If you have any questions i will try and answer them,so please ask

S.

PS: Some basic mathematical knowledge is required.
PPS: All text and drawings are created by myself and are therefor copyrighted to me. If you want to copy it,please ask me and you'll probably get my permission If you dont ask me,you know i can sue your ass




The thermodynamics of the engine

Sources:
- powerpoint presentations from uni.
- Bosch Technische leergang Thermodynamica van Verbrandingsmotoren.
- knowledge

i assume you know the basic principle of the combution engine:
- Injection
- compression
- ignition
- exhaust


General stuff

- bore - D (in meter) - diameter of the cilinder
- stroke - S (in meter) - The stroke of the piston is the distance from the Top Dead point (TDP) to the Bottom dead point (BDP).
- Stroke volume - Vs - This is the volume that is moved by the piston. So this is the volume between the TDP and the BDP.

V’s = π / 4 * D2 * S - answer in m3

For an engine with z clinders the total Stroke volume is Vs = V’s * z
Z is the number of cylinders.

- The volume of the combustion chamber or compressionvolume is known as Vc . This is the volume of the combustion chamber when it is in the TDP. This is also called Compression space.

- Compression relation (hope this is the correct translation, please correct me if wrong). For this we have two different indications:
- the nominal compression relation ε . this is the normal indication by the manufacturers.
ε = Volume above the piston in BDP / volume above the piston in TDP
or
ε = V’s + Vc / Vc

See attached drawing number 1

- The true or effective compression relation εeff. This is calculated by using either one of the next two formulas.
Εeff = Volume above the piston at the time of closing inlet valve / volume above piston in TDP.
Or
Εeff = V’seff. + Vc / Vc
See attached drawing number 2


page 2 following pretty soon (either tonight or tomorrow morning).

[lightweight]

Maybe you mean compression ratio, instead of compression relation

Really useful data!!!

Maybe you can post the powerpoint slides????
All of them?????
Until the end of your course?????

[dromeas]

Thanks. keep up

[deffenbaugh03]

Thank you drakkie, I look forward to seeing the other 30. I'm pretty sure I would like to be an automotive engineer as well when i 'm older so keep it up

[Quiggs]

More common language is "Top Dead Center (TDC)" and "Bottom Dead Center (BDC)."

Good info to have.

[h00t_h00t]

I'd take the smiley out of your sources, it just looks unprofessional

[drakkie]

Originally Posted by lightweight

Maybe you mean compression ratio, instead of compression relation

Really useful data!!!

Maybe you can post the powerpoint slides????
All of them?????
Until the end of your course?????

Some slight problems:
- ucp doesnt support uploading powerpoint slideshows
- copyrighted ?
- they are completely in Dutch

[rahul81f]

Me a mechanical automobile engineer too.

[Bob]

just wanted to point out that this:

V’s = π / 4 * D2 * S

should read like this:

V's = (pi/4)(D^2)*S

seeing it as D2 can be confusing made you tried to superscript it and it didn't work?

[jediali]

Nice work. I found in my engineering degree, automotive stuff was not considered. I therefore wrote up my own work and done my thesis on F1 crankshaft balance. Now i enjoy reading various textbooks about this sort of stuff. keep it up

[drakkie]

Originally Posted by jediali

Nice work. I found in my engineering degree, automotive stuff was not considered. I therefore wrote up my own work and done my thesis on F1 crankshaft balance. Now i enjoy reading various textbooks about this sort of stuff. keep it up

Well i am 100% sure that the book i mentioned above will interest you. I have a ISBN# for you of the Dutch version:
90 6674 907 5

It is printed by Delta press. I think informing there on how to order english versions is a good plan. They have many,many books on automotive subjects.

Unfortunately my sparetime is rare. I will try and do some more on this soon...

Edit:
Bosch also has some great books. google gave me this as the first link:
http://www.bentleypublishers.com/bosch/index.htm

ALso if you are good in German,the Vieweg Handbuch kraftfahrzeugtechnik is a very good book.