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TD42, is it a Full or Swirl pre-cumbustion chamber?

Posted: Fri Apr 16, 2010 4:17 pm
by Abitibi
Quick question.

Anyone knows if my GQ 4.2 n/a diesel has a swirl combustion chamber or a full pre-combustion chamber similar to the older Mercedes?

Thinking ahead for my veggie conversion, ie. single tank vs. dual tank...

Thanks!
David

Posted: Sun Apr 18, 2010 11:55 am
by PGS 4WD
Full pre comp chamber on all TD42, turbo and non-turbo

Posted: Sun Apr 18, 2010 5:23 pm
by Abitibi
Thanks for the reply.

I dug these definitions comparing the swirl vs. the full prechamber, just trying to understand the concept. Doesn't the TD42 have a tangential throat like described below in the swirl chamber? I'm still trying to grab an understanding of these chambers...

SWIRL CHAMBER:

It consists of a spherical chamber located in the cylinder head and separated from the engine cylinder by a tangential throat. About 50% of air enters this swirl chamber during compression stroke of the engine producing a swirl.

The products after combustion returns through the same throat to the main cylinder at much higher velocity. So more heat loss to walls of the passage takes place. Such type of chambers finds application in those engines where fuel control and engine stability is more important than fuel economy. These are Ricardo chambers.


PRECOMBUSTION CHAMBER:

This chamber is located at the cylinder head and is connected to the engine cylinder by small holes. It occupies 40% of the total cylinder volume. During the compression stroke, air from the main cylinder enters the precombustion chamber. At this moment, fuel is injected into the precombustion chamber and combustion begins. Pressure increases and the fuel droplets are forced through the small holes into the main cylinder, resulting in a very good mix of the fuel and air. The bulk of the combustion actually takes place in the main cylinder. This type of combustion chamber has multi-fuel capability because the temperature of the prechamber vaporizes the fuel before the main combustion event occurs.