Mechanical Design, Manufacturing and Engineering Forum
[ Home ] [ Search ] [ Engineering and Design Database ] [ Product and Services Directory ]
[ Engineering Forum ] [ DFM DFA Training and Trainers ] [ GD&T Training GD&T Trainers ] [ Advertise ]
[ Archive#1 ] [ Archive #2 ] [ Archive #3] [ Calculators ]
Forum Moderators: randykimball, Administrator

Need Help Understanding Diesel Cycle Question
Post Reply   Forum
Posted by: Rebecca Pierik ®

05/27/2005, 10:25:21
Author Profile Mail author Edit
Dear Engineers,

I'm editing a textbook about technology and engineering for high schools students and am wondering if one of you may be able to shed some light on a topic of discussion in our editorial group, which includes engineers and non-engineers.

In one of our chapters we discuss the diesel cycle using the gas laws. (The text is for ninth-graders, so we're trying to keep it fairly simple without sacrificing accuracy. Here's how we currently explain the cycle in our draft:

1. As the piston drops, the intake valve opens, and air is taken into the chamber.
2. The intake valve closes, and the piston presses against the air inside of the cylinder, compressing it. As the volume of the chamber decreases, the pressure and temperature of the air inside the chamber increases.
3. Fuel is injected into the hot, high-pressure air inside the chamber. It combusts immediately, creating an explosion. The explosion increases the pressure and temperature of the chamber very quickly. The expanding gas in the chamber pushes the piston down with great force.
4. As the piston rises a second time, the exhaust valve opens, and the smoke from the explosion exits the engine as exhaust.

I understand how the pressure in the chamber pushes the piston down in step 3, but i'm having a hard time understanding what causes the piston to rise or fall in steps 1,2, and 4. Is it that the piston is working in tandem with other cyliders that push or pull on it? Does it have something to do with temperature variations in the beofre and after the explosion? chamber?







Post Reply | Recommend | Alert View All   | Next |

Replies to this message


Re: Need Help Understanding Diesel Cycle Smile
Re: Need Help Understanding Diesel Cycle -- Rebecca Pierik Post Reply Top of thread Forum
Posted by: spgautam ®

06/26/2005, 10:38:17
Author Profile Mail author Edit
Dear friend
hi basically what happens is that in any engine an nergy storing device called flywheel is attached which stores energy during power stroke that is when fuel is burned and piston starts moving down due to expansion and it release the stored energy in other steps about which you are asking . energy stored depends upon the mass moment of inertia of flywheel used . hopefully problem is solved . if not feel free to ask
bye
spgautam






Post Reply | Recommend | Alert Where am I? Original Top of thread
Re: Need Help Understanding Diesel Cycle
Re: Need Help Understanding Diesel Cycle -- Rebecca Pierik Post Reply Top of thread Forum
Posted by: randykimball ®
Barney
05/30/2005, 22:10:17
Author Profile Mail author Edit
Hi, and welcome,

Here is an excellent site with simple steps well explained in about the same level you would be using. Perhaps the author would like to hear form you and offer some advice or copyright usage.

https://www.qrg.northwestern.edu/thermo/design-library/diesel/diesel.html

If you do not get what you need or if you have any more questions PLEASE ask.

-randy-




The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.


Post Reply | Recommend | Alert Where am I? Original Top of thread | |
Re: Need Help Understanding Diesel Cycle
Re: Re: Need Help Understanding Diesel Cycle -- randykimball Post Reply Top of thread Forum
Posted by: Kelly_Bramble ®

05/31/2005, 08:16:49
Author Profile Mail author Edit
You can find a basic explanations on Diesel Cycles on the Engineers Edge at /power_transmission/power_transmission_menu.shtml as well.






Post Reply | Recommend | Alert Where am I? Original Top of thread | |
Re: Need Help Understanding Diesel Cycle
Re: Re: Need Help Understanding Diesel Cycle -- Kelly_Bramble Post Reply Top of thread Forum
Posted by: randykimball ®
Barney
05/31/2005, 20:03:39
Author Profile Mail author Edit
... And a GREAT explanation it is. Wow, this is tremendously fast growing data base and an increasingly fantastic asset of a web site !!!!

I must go browsing around in it again. .. and more often..

Great Job !!!!!!!!

it is good to be connected.

-randy-




The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.


Post Reply | Recommend | Alert Where am I? Original Top of thread
Re: Need Help Understanding Diesel Cycle
Re: Need Help Understanding Diesel Cycle -- Rebecca Pierik Post Reply Top of thread Forum
Posted by: zekeman ®

05/27/2005, 14:19:14
Author Profile Mail author Edit
Inertia. There is energy delivered during the power stroke which is stored in the flywheel which is part of the design. Thus duiroing the nonpower parts of the cycle the system rotates and expemnds part of the energy stored.






Post Reply | Recommend | Alert Where am I? Original Top of thread | |
Re: Need Help Understanding Diesel Cycle Question
Re: #3789 -- zekeman Post Reply Top of thread Forum
Posted by: Rebecca Pierik ®

05/27/2005, 15:16:02
Author Profile Mail author Edit
Thanks. I appreciate your responses. And I have one more question then:
What about the very first intake stroke and compression stroke (steps 1 and 2) before the flywheel is turning (when the vehicle moves from rest)?

Thanks Again,
Rebecca







Post Reply | Recommend | Alert Where am I? Original Top of thread | |
Re: Need Help Understanding Diesel Cycle
Re: Re: Need Help Understanding Diesel Cycle -- Rebecca Pierik Post Reply Top of thread Forum
Posted by: zekeman ®

05/27/2005, 23:50:08
Author Profile Mail author Edit
Just like in your automobile, there is a starting motor that sets the cycle in motion.






Post Reply | Recommend | Alert Where am I? Original Top of thread

Powered by Engineers Edge

© Copyright 2000 - 2024, by Engineers Edge, LLC All rights reserved.  Disclaimer