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Bio diesel and common rail now engine basics

G

Guest

Guest
JB wrote...
Sorry but heres a few of the usual stupid questions Sorry.
What is the head and what is in it,
I know fuel is pumped into the engine to push the pistons down by an
explosive action which in sequence will drive the crankshaft but where else
will fuel go or end up in the combustion process.
It just to me Diesel is a lot tinner in voscosity that veg oil and I just
dont see how an engine made to use one can run on the another with out any
issues over time. I know im sad but thats me.
How come Diesels cant use petrol or the petrol ones cant use Diesel or is
that a whole book to read with a bottle of plonk.
SNIP
Hey JB, are you trying to set me my homework for the week ?
All this stuff I am sure is better explained in some of those on-line
books like the engine oil bible and so-on. But I will take-up the
challenge cos its you. I refer to generic principles here, and not
specific to TLC's.
What is the head and what is in it,
==============Its the lid on the engine containing the inlet and exhaust valves,
fuel injector and glow plug if you have that system. Each cylinder
when the piston is down at the bottom of its stroke has a capacity of
about 700cc in your 80. Piston comes up the bore and with the valves
in the head shut, it squeezes the air inside into a small space
under/within the head. The air gets hot when squeezed, and at just
the right time a few degrees before the piston is right at the top of
its stroke, the injector squirts a fine mist of fuel into it. The
fuel then undergoes a controlled burn in the hot air and pushes the
piston down on the power stroke. All the gubbins that makes the
engine fire and then exhaust effectively is contained within the head
and driven by the cambelt.
where else will fuel go or end up in the combustion process.
====================When cold some will not be burnt and go out the exhaust, this will
also happen when you open the throttle suddenly - the black smoke you
see is the unburnt fuel.
When cold, some fuel can condense on the inside of the bore and will
be swept down into the crankcase by the piston rings. They should
provide a good seal, but the older and more worn the engine the more
this will happen and will dilute the oil in the sump.
To me Diesel is a lot tinner in voscosity that veg oil and I just
dont see how an engine made to use one can run on the another with out any
issues over time.
====================I won't get into that argument here as we have some mates putting it
into their tank mixed with diesel with good results - so far. If you
want to run on 100% biodiesel then you have to buy the esterised
(processed) stuff, just like Julian's supplier.
How come Diesels cant use petrol or the petrol ones cant use Diesel or is
that a whole book to read with a bottle of plonk.
=================== From what we know of you JB the glass can only contain water when
you read that book ;-)
Petrol is so much more volatile and only needs a spark to set it off.
Diesel is not volatile (or so much anyway) and will not burn in the
presence of a spark. So that is why it burns best when injected into
the hot atmosphere of compressed air in the cylinder. So you can add
some (max 10%) petrol to diesel to make it burn better if its very
poor quality, as my brother-in-law does in Russia. But put diesel in
petrol and it just won't burn with a spark. Put neat petrol into a
diesel and the engine blows-up.
The amount the air that is compressed in a diesel is about 18:1
ratio but can be up to 22:1 or so. In a petrol it is much less at
about 9:1. So with the much higher pressure in the cylinder of a
diesel the block has to be made in a much heavier construction.
I know im sad but thats me.
=====================Yes JB but your wife loves you and all your mates here enjoy helping
you out as you are so open at your wish to learn. Its a pleasure!
Cheers
Jon
Grand Union Canal
'92 HZJ80 ex UN surplus from Bosnia
 
Bio diesel and common rail now engine basics and rant

Hey Jon-C-W
Thanks again for the info. So clear and concise, saves me having to read a
book.
I have this craving at times like I suppose a pregnant woman does for weird
food except in my case its questions about things.
You have done well, still not losing the head with me at least on line.
Id say now when you read some of my stuff you have a few well vexed words
to yourself and then self composure takes over and you reply to me. Ah sure
you and the other unlucky few might get bored without the questions.
Im just glad at times I live so far away from you all. So please send me a
1HDT engine complete by post so i can take it apart and put together in
perfect order just wih extra bits left over that I really dont need anyway
Right. Thanks
John C
92HDJ 80 1HDT Rep of Ireland
 
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