Uses of different Piston Crown designs?

DSC.CUSTOMS · 18th July 2011, 13:23

Hi everyone ,
I recently visited the Federal Mogul Goetze factory . It was a good experience watching them make various pistons , piston rings and gudgeon pins . I quite liked the variation in sizes of the pistons i.e from a moped to a tank(forged piston)

.However there was a question which struck my mind when i saw various piston crowns . Most of the pistons i saw had a different crown design on them .
Now my obvious question is that - What are the various uses of different piston crown designs ?
I wanted to ask this question to the head of the piston workshop but he wasn't available then . The workers didnt know much about it . Also i couldnt find much on the internet as well.
I request all the guru's to enlighten me on this particular topic . If anyone finds a suitable link then please post it here .
Regards .

MODS- You may move this to an appropriate section ,if required .

aaggoswami · 18th July 2011, 16:09

To the best of my knowledge, Piston crown plays a very critical role in compression ratio of an engine. Moreover, it has to take a lot of stress and transmit the thrust. This depends a lot upon engine.

As per the engine requirement, different types of crowns are used. In some cases the crowns are so designed that can take load of higher output when the engine is modded. In some cases, the crown has round deeper surface for valve operations.

Would like to update myself further.

vina · 18th July 2011, 17:03

Crowns have multiple functions:

1. convert the pressure developed in ignition stroke to a downward force - carry that force to the piston rod
2. sustain pressure waves generated by occasional knocking
3. act as a thermal barrier between cylinder and crank area
4. introduce swirl in the fuel - controls knocking and helps more uniform combustion

...

you can get more info here:

Introduction to piston design for forced induction engines | Supercharger Performance and Engine Performance Parts

Randhawa · 18th July 2011, 17:05

Mostly its designed as per requirement of compression/valve to piston clearance and Squish area. That is keeping in mind the location of the spark plug and how or from where the flame will progress.

dhanushs · 18th July 2011, 17:53

To my best knowledge, piston crown is designed to

Fight reversion
Aid flow velocity
Induce swirl.

18th July 2011, 13:23	#1
DSC.CUSTOMS BHPian Join Date: Jun 2009 Location: Patiala,Chandigarh Posts: 179 Thanked: 12 Times	Uses of different Piston Crown designs? Hi everyone , I recently visited the Federal Mogul Goetze factory . It was a good experience watching them make various pistons , piston rings and gudgeon pins . I quite liked the variation in sizes of the pistons i.e from a moped to a tank(forged piston) .However there was a question which struck my mind when i saw various piston crowns . Most of the pistons i saw had a different crown design on them . Now my obvious question is that - What are the various uses of different piston crown designs ? I wanted to ask this question to the head of the piston workshop but he wasn't available then . The workers didnt know much about it . Also i couldnt find much on the internet as well. I request all the guru's to enlighten me on this particular topic . If anyone finds a suitable link then please post it here . Regards . MODS- You may move this to an appropriate section ,if required .
	() Thanks

18th July 2011, 16:09	#2
aaggoswami Senior - BHPian Join Date: May 2007 Location: Vadodara Posts: 4,997 Thanked: 3,012 Times	Re: Help: Uses of different Piston Crown designs . To the best of my knowledge, Piston crown plays a very critical role in compression ratio of an engine. Moreover, it has to take a lot of stress and transmit the thrust. This depends a lot upon engine. As per the engine requirement, different types of crowns are used. In some cases the crowns are so designed that can take load of higher output when the engine is modded. In some cases, the crown has round deeper surface for valve operations. Would like to update myself further.
	(2) Thanks

18th July 2011, 17:03	#3
vina Senior - BHPian Join Date: Dec 2010 Location: Ghaziabad/Hyderabad/Mysore Posts: 1,435 Thanked: 345 Times	Re: Uses of different Piston Crown designs? Crowns have multiple functions: 1. convert the pressure developed in ignition stroke to a downward force - carry that force to the piston rod 2. sustain pressure waves generated by occasional knocking 3. act as a thermal barrier between cylinder and crank area 4. introduce swirl in the fuel - controls knocking and helps more uniform combustion ... you can get more info here: Introduction to piston design for forced induction engines \| Supercharger Performance and Engine Performance Parts
	(2) Thanks

18th July 2011, 17:05	#4
Randhawa Senior - BHPian Join Date: Oct 2007 Location: Brighton Posts: 1,203 Thanked: 361 Times	Re: Uses of different Piston Crown designs? Mostly its designed as per requirement of compression/valve to piston clearance and Squish area. That is keeping in mind the location of the spark plug and how or from where the flame will progress.
	(2) Thanks

18th July 2011, 17:53	#5
dhanushs Distinguished - BHPian Join Date: Oct 2009 Location: Chennai Posts: 4,450 Thanked: 11,515 Times	Re: Uses of different Piston Crown designs? To my best knowledge, piston crown is designed to Fight reversion Aid flow velocity Induce swirl. Last edited by dhanushs : 18th July 2011 at 17:57.
	(2) Thanks