OT: Pinking Diesel Engine

[Chris]

Hi all,

How is it possible for a diesel engine (given the correct grade of fuel)
to pink? Obviously with petrol, you can advance the ignition to produce
the effect, but with derv, combustion is determined kind of automatically
by the compression level (AFAIK) and is therefore fixed. Yet my diesel
car's been pinking since the garage changed the EMU and I'm sure I'm not
imagining it. How is that even possible?
Any ideas?

Ta.

[Dan S. MacAbre]

I don't know much about diesel, but I expect the injection has to be
timed. I think the idea is that air alone is compressed, and then the
fuel sprayed into it at the appropriate moment, when the air is very hot.

[NY]

"Chris" <c...@noreply.com> wrote in message
news:nt991o$vhp$4...@dont-email.me...

Maybe the ECU is injecting fuel too early, before the piston reaches TDC.
That would have virtually the same effect as the spark plug on a petrol
engine firing too soon.

[Richard]

"Chris" wrote in message news:nt991o$vhp$4...@dont-email.me...

Have you just had a VW 'fixed' for the emissions?

[The Natural Philosopher]

It all depends utterly on the software and mapping used as to how much
of a knock the engine will give. Lean early injection will be more fuel
efficient, produce more NOx and pink more.

And since mapping is somewhat of a moveable feast depending on the
sensors attached to the engine and their condition, and the software, I
would be asking why the EMU was changed.

And what it was changed for...

--
Those who want slavery should have the grace to name it by its proper
name. They must face the full meaning of that which they are advocating
or condoning; the full, exact, specific meaning of collectivism, of its
logical implications, of the principles upon which it is based, and of
the ultimate consequences to which these principles will lead. They must
face it, then decide whether this is what they want or not.

Ayn Rand.

[Chris Green]

Diesels 'knock' or 'pink' to work, it's what they do. Now whether you
should *hear* a noise that sounds like that is another matter.

--
Chris Green
·

[Richard]

"Chris" wrote in message news:nt991o$vhp$4...@dont-email.me...

If this is after a VW 'fix', take it back and get them to put it right.
Daughter's 2.0 TDI Golf had similar issues post fix. They first said it was
a dirty EGR which they allegedly cleaned, but the problem persisted. I had a
chat with the service guy and pointed out it was their fault, and they must
rectify it. After further investigation, they allegedly found some soot
which was interfering with the operation of a valve or some other bollocks -
but the problem has gone away for now. Dealer techs were appreciative of the
learning opportunity.
Check Honest John for other experiences.

[Chris]

On Sat, 08 Oct 2016 10:09:29 +0100, Richard wrote:

> Have you just had a VW 'fixed' for the emissions?

Nope. Nowt to do with VW, this is a Land Rover. The EMU was changed
because the original one (which ran quietly) packed up.

[Bob Minchin]

I've been looking at car code readers recently thinking of upgrading and
one feature mentioned by so is the ability to reprogramme the injectors
( I know not what features can be changed)
So maybe whatever programming data for the injectors in your old ECU
have not been set up the same in the new one?

I'd be going back to the dealer and "discussing" it with them.
Have you driven it enough to get an idea of the fuel consumption and how
that compares with before?
In my experience degradation in fuel consumption comes with almost
anything being sub-optimal in the engine control system.

[Dave Plowman (News)]

In article <ntaqur$9k2$1...@dont-email.me>,

Bob Minchin <bob.minc...@YOURHATntlworld.com> wrote:
> I've been looking at car code readers recently thinking of upgrading and
> one feature mentioned by so is the ability to reprogramme the injectors
> ( I know not what features can be changed)
> So maybe whatever programming data for the injectors in your old ECU
> have not been set up the same in the new one?

I really can't see how a new ECU wouldn't be correct in this respect. It
might well start off with a base map, and learn the actual engine's
characteristics. But this isn't going to take long.

--
*The fact that no one understands you doesn't mean you're an artist

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

[Fredxxx]

On 08/10/2016 15:13, Dave Plowman (News) wrote:
> In article <ntaqur$9k2$1...@dont-email.me>,
> Bob Minchin <bob.minc...@YOURHATntlworld.com> wrote:
>> I've been looking at car code readers recently thinking of upgrading and
>> one feature mentioned by so is the ability to reprogramme the injectors
>> ( I know not what features can be changed)
>> So maybe whatever programming data for the injectors in your old ECU
>> have not been set up the same in the new one?
>
> I really can't see how a new ECU wouldn't be correct in this respect. It
> might well start off with a base map, and learn the actual engine's
> characteristics. But this isn't going to take long.

If this engine is of the Duratorque, much of the mapping is carried out
at the dealer and there is very little learning.

I believe the pinking the OP hears is the multiple injection times at
part throttles. At full throttle this sound should go away.

BICBW

[Chris]

Just wondering if it's doing the engine any harm running it with this
slight pinking. I haven't noticed any difference one way or the other
with fuel consumption or performance.

[Dave Plowman (News)]

In article <ntb2jc$gk2$4...@dont-email.me>,

Older diesel designs used to knock like the clappers. We've got a bit
spoilt by modern ones in this respect. Pity they've not managed to do
anything about the stink, though. ;-)

--
*I stayed up all night to see where the sun went. Then it dawned on me.*

[newshound]

You need to ask Mr Cheerful, hence the cross post. Might be helpful to
mention exactly which model Land Rover.

[MrCheerful]

The ignition cannot start until the actual moment of injection. So you
first need to get the timing checked. Don't leave it as it can wreck
the engine.

[The Natural Philosopher]

Do you actually know how the injection timning works on a modern diesel?

--
No Apple devices were knowingly used in the preparation of this post.

[MrCheerful]

Please tell me why the timing cannot be wrong.

[MrCheerful]

On 08/10/2016 17:44, The Natural Philosopher wrote:

Please enlighten us.

[newshound]

How modern is a Land Rover diesel anyway?

[MrCheerful]

On 08/10/2016 17:44, The Natural Philosopher wrote:

The principal of the diesel engine has not changed since it was
invented, it needs correct timing to run properly, and incorrect timing
can wreck it.

Can you explain what you infer is wrong with these statements?

[The Natural Philosopher]

Don't change the subject.

How do you propose anyone 'checks the timing'



--
“It is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.”

Thomas Sowell

[The Natural Philosopher]

Oh no, you claim to be the expert.

How would you 'check the timing'' on a diesel engine?


--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

[The Natural Philosopher]

Depends on the Land rover

[The Natural Philosopher]

First tell; me what you thing determines the 'timing' on a modern
diesel, and how you can 'measure' it, and how you can 'change' it.

[Fredxxx]

Then explain why you say "Do you actually know how the injection timning
works on a modern diesel" after he said get the timing checked.

> How do you propose anyone 'checks the timing'

Are you suggesting you don't know?

[Fredxxx]

After you said "Do you actually know how the injection timning works on
a modern diesel" you seem to be claiming that ground.

> How would you 'check the timing'' on a diesel engine?

[Fredxxx]

Obviously young enough to have a ECU.

[Fredxxx]

We were all hoping you'd be telling where Mr Cheerful statements might
be wrong.

Do tell...........

[Clive George]

On 08/10/2016 17:44, The Natural Philosopher wrote:

I suspect he does, because he's given the correct answer. If the
injection starts early, it'll pink. It can start early if the computer
thinks the crank is in a different position to where it actually is.

[Fredxxx]

We don't know yet the engine the OP has, whether its high pressure rail
or a hybrid, old pump but still drive by wire. The OP said the EMU was
replaced, but I'm wondering if this was really the EDU associated with
his pump or some other on-board control unit.

Without more info Mr Cheerful's answer is the right one.

[polygonum]

On 08/10/2016 19:29, Clive George wrote:

> It can start early if the computer thinks the crank is in a different
> position to where it actually is.

Not with you there - how can what the computer thinks affect the
physical state within the cylinder? The computer could ...

Bomb#20: In the beginning, there was darkness. And the darkness was
without form, and void.

Boiler: What the hell is he talking about?

Bomb#20: And in addition to the darkness there was also me. And I moved
upon the face of the darkness. And I saw that I was alone. Let there be
light.

But how do the ECU's thoughts impact on the detonation?

--
Rod

[MrCheerful]

The start of combustion is NOT triggered by the level of compression.

[Fredxxx]

On 08/10/2016 19:37, polygonum wrote:

That does depend on the position of the crank sensor and whether this
has been correctly programmed into the ECU. We still don't know the OP's
engine so not sure what this has to do with bombs and boilers.

There are generally a few fault codes associated with injection timing.
I have read articles that under a fault condition the fuel pump goes to
full advance on certain types.

[MrCheerful]

On 08/10/2016 17:44, The Natural Philosopher wrote:

Please enlighten us.

The principal of the diesel engine has not changed since it was
invented, it needs correct timing to run properly, and incorrect timing
can wreck it.
Can you explain what you infer is wrong with these statements?

[newshound]

+1

[Peter Hill]

On 08/10/16 7:46 PM, Fredxxx wrote:
> On 08/10/2016 19:37, polygonum wrote:
>> On 08/10/2016 19:29, Clive George wrote:
>>> It can start early if the computer thinks the crank is in a different
>>> position to where it actually is.
>>
>> Not with you there - how can what the computer thinks affect the
>> physical state within the cylinder? The computer could ...
>>
>> Bomb#20: In the beginning, there was darkness. And the darkness was
>> without form, and void.
>>
>> Boiler: What the hell is he talking about?
>>
>> Bomb#20: And in addition to the darkness there was also me. And I moved
>> upon the face of the darkness. And I saw that I was alone. Let there be
>> light.
>>
>> But how do the ECU's thoughts impact on the detonation?
>
> That does depend on the position of the crank sensor and whether this
> has been correctly programmed into the ECU. We still don't know the OP's
> engine so not sure what this has to do with bombs and boilers.

The ECU was given the attribute of thinking. Computer consciousness is
quite still not reality.

The "Bomb#20" in question was a character in the film "Dark Star". It's
power of thought caused some problems, it wasn't very interested in
doing it's job of detonation. A "pet" that resembled an animated beach
ball with duck's webbed feet also caused problems.

He could have gone for HAL in 2001 .. more trouble.

Or Skynet .. guess what?

--
Peter Hill
replace nospam with domain host name to reply

[Fredxxx]

I feel much wiser - thank you.

Of course Dark Star must have been before I was born!! What's 2001? :-)

[NY]

"polygonum" <rmoud...@vrod.co.uk> wrote in message
news:e5ssn7...@mid.individual.net...

Because the detonation begins when the fuel injection begins - and if the
crank-position sensor thinks a given piston is in a different position it
will inject the fuel early or late of the correct position of the piston.

[NY]

"MrCheerful" <g.odon...@yahoo.co.uk> wrote in message
news:P9bKz.2178482$jB.7...@fx43.am4...

> On 08/10/2016 19:37, polygonum wrote:
>> On 08/10/2016 19:29, Clive George wrote:
>>> It can start early if the computer thinks the crank is in a different
>>> position to where it actually is.
>>
>> Not with you there - how can what the computer thinks affect the
>> physical state within the cylinder? The computer could ...
>>
>>

>> But how do the ECU's thoughts impact on the detonation?
>>
>
> The start of combustion is NOT triggered by the level of compression.

I'm wondering whether Polygonum (I think, if I've got the quoting correct -
if not, apologies) thinks that detonation *is* triggered by the compression
reaching some critical level - in other words, that fuel is injected
arbitrarily early and then detonates when the pressure and/or mixture
temperature subsequently reaches the "right" level - which is not how it
works.

As I understand it, air (and nothing but air) is sucked/blown (*) into the
cylinder on the inlet stroke, and is compressed on the compression stroke
which raises its temperature above the point at which fuel will
spontaneously ignite/detonate if it comes in contact with the air. At the
correct moment (which may be x milliseconds rather than y degrees before top
dead centre, fuel injection begins. The fuel ignites as it comes in contact
with the air and continues to burn for as long as the fuel is injected.

The correct instant of injection is determined by a TDC sensor which the ECU
uses as a reference point to determine the time offset to the injection
point, based on engine speed so fuel injection will always have *finished*
before the piston reaches the bottom of its travel on the power stroke and
the exhaust valve opens, since any fuel injected after this time will not
increase the cylinder pressure (and hence contribute to engine power) but
will instead go straight out of the exhaust.

(*) Depending on whether engine is normally aspirated or turbo/super
charged.

[NY]

"Fredxxx" <fre...@nospam.com> wrote in message
news:ntbeuh$geg$1...@dont-email.me...

> That does depend on the position of the crank sensor and whether this has
> been correctly programmed into the ECU.

And this changes when the crank sensor is changed - as I found out when I
took my car to the local garage in my village to have the cambelt replaced
at the stated mileage. The replacement of the belt was straightforward but
the associated sensor needed to be replaced as well. I'm not sure whether
the old one broke during removal of the old belt or whether the sensor
replacement was a routine part of belt replacement.

The garage took five days (!) to manage to reprogram the ECU for the fact
that the sensor had changed and either gave a different voltage-versus-time
curve as the TDC was reached or else was in a slightly different position.
The change in timing of the critical TDC event was enough to prevent the
engine running properly and they had to call out someone from Peugeot to
advise on adjusting the ECU to compensate.

The engine ran perfectly once they adjusted it properly (it ran for another
30,000 miles until I sold the car) but it took a long time for them to get
it going. I happened to be cycling past the garage late one evening to go
shopping (after five days without a car I was running out of things) and
they were still working on my car and trying to start the engine. Suddenly I
heard a yell of delight as it fired - and carried on running smoothly. I
stopped to see how things were going and the engineer was dancing round the
room and punching the air in delight.

I stopped using that garage after this incident, and an earlier one where
the garage had replaced a broken "fan belt" and the replacement failed a
thousand miles later because they hadn't diagnosed the bent pulley flange
that had *caused* the original belt failure, and wouldn't give me any refund
for shoddy workmanship that required the work to be repeated.

[Bob Eager]

Because the detonation is caused not by compression ignition these days,
but by the injector timing.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

[Bob Eager]

On Sat, 08 Oct 2016 22:08:01 +0100, Fredxxx wrote:

> Of course Dark Star must have been before I was born!! What's 2001?

Probably. Certainly pre-dates the early 1990s, when Tubular Bells II was
released.

(many tracks on TBII are named after science fiction stories, and one of
them is Dark Star)

[Dave Plowman (News)]

In article <L7-dnavVJbzX_WTK...@brightview.co.uk>,

NY <m...@privacy.net> wrote:
> Because the detonation begins when the fuel injection begins - and if
> the crank-position sensor thinks a given piston is in a different
> position it will inject the fuel early or late of the correct position
> of the piston.

Crank position sensor and trigger wheel or whatever on production engines
are generally fixed. The ECU, however, can fire the injectors at any point
according to its mapping.

--
*Eat well, stay fit, die anyway

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

[Cursitor Doom]

On Sat, 08 Oct 2016 22:23:15 +0100, NY wrote:

> I'm wondering whether Polygonum (I think, if I've got the quoting
> correct - if not, apologies) thinks that detonation *is* triggered by
> the compression reaching some critical level - in other words, that fuel
> is injected arbitrarily early and then detonates when the pressure
> and/or mixture temperature subsequently reaches the "right" level -
> which is not how it works.

it used to be how it worked donkey's years ago, though. In a normally-
aspirated diesel engine (they don't make 'em any more 'cos they're shite)
the diesel is sucked in along with air and spontaneously combusts when
the compression level and cylinder temperature reach a certain point. But
I don't think they've been made that way for decades now.

[Dave Plowman (News)]

In article <irCdnQWU3Y9i-mTK...@brightview.co.uk>,

NY <m...@privacy.net> wrote:
> "Fredxxx" <fre...@nospam.com> wrote in message
> news:ntbeuh$geg$1...@dont-email.me...
> > That does depend on the position of the crank sensor and whether this has
> > been correctly programmed into the ECU.

> And this changes when the crank sensor is changed - as I found out when
> I took my car to the local garage in my village to have the cambelt
> replaced at the stated mileage. The replacement of the belt was
> straightforward but the associated sensor needed to be replaced as
> well. I'm not sure whether the old one broke during removal of the old
> belt or whether the sensor replacement was a routine part of belt
> replacement.

> The garage took five days (!) to manage to reprogram the ECU for the
> fact that the sensor had changed and either gave a different
> voltage-versus-time curve as the TDC was reached or else was in a
> slightly different position. The change in timing of the critical TDC
> event was enough to prevent the engine running properly and they had to
> call out someone from Peugeot to advise on adjusting the ECU to
> compensate.

I'm rather surprised at that. Don't know every engine of course, but
sensors are usually rigidly mounted - and designed to a tolerance whereby
changing them doesn't involve any re-programming.

A VR type sensor has an input stage on the ECU which looks for the zero
crossing point - so the varying voltage output doesn't matter. Hall effect
give a constant voltage output regardless of speed.

And the timing is only critical for best running. Most modern engines with
a cam position sensor will run in a limp home mode if the crank position
one fails.

--
*Why isn't 11 pronounced onety one? *

[Cursitor Doom]

On Sat, 08 Oct 2016 19:49:00 +0100, MrCheerful wrote:

> The principal of the diesel engine has not changed since it was
> invented, it needs correct timing to run properly, and incorrect timing
> can wreck it.
> Can you explain what you infer is wrong with these statements?
>
> Please tell me why the timing cannot be wrong.

I don't claim to be any expert on this subject (far from it) but the
*original* diesel engines were (more or less) normally-aspirated, were
they not? Hence why you can use aerosols like 'Easy Start' to get the
fuckers going from cold. I wonder if they still make Easy Start - anyone
know?

[Clive George]

They never made them that way. The diesel was always injected into the
compressed air near TDC.

Have a read of https://en.wikipedia.org/wiki/Diesel_engine

Now glow plug engines, the tiny two strokes used for models, are a
different game - but they're not diesels.

[Clive George]

On 08/10/2016 23:39, Bob Eager wrote:

>> But how do the ECU's thoughts impact on the detonation?
>
> Because the detonation is caused not by compression ignition these days,
> but by the injector timing.

It always was injector timing. These days the injectors are controlled
electrically, but they were mechanical in the past - the diesel pump was
a timed device, sending a pulse of fuel to each injector at the
appropriate time.

[Clive George]

Yes, you could put some more volatile fuel into the air to help them
start - and indeed you might even be able to run the thing on it if you
had enough and could cope with the pinking which would result. But for
normal running on the oily stuff you get from the pump, the bang starts
when the fuel is injected.

Normally-aspirated means something else - merely no turbo. You can run a
modern diesel normally aspirated, just disconnect the air pipe from the
turbo or open the waste gate. It won't go anything like as well, but it
will work.

(had an interesting problem after having my cam belt changed. The car
felt quite slow when I drove it home. Stared at it for a while, then
plugged a computer in, whereupon it told me the electrovalve wasn't
working. After a certain amount of internet reading, eventually worked
out they meant the two pressure sensors - and yes, there were two wires
which hadn't been reconnected. Plug them in, it runs a lot better.

What happened was the ECU wasn't sensing anything, so it opened the
waste gate on the turbo for safety. You could see the difference on the
air pipes - with the sensor disconnected, pressing the accelerator meant
the pipe was sucked in as the engine ran faster. Connect it up, the pipe
expanded as the turbo forced more air into the system instead.)

[Weatherlawyer]

On Saturday, 8 October 2016 12:19:41 UTC+1, Chris wrote:
> On Sat, 08 Oct 2016 10:09:29 +0100, Richard wrote:
>
> > Have you just had a VW 'fixed' for the emissions?
>
> Nope. Nowt to do with VW, this is a Land Rover. The EMU was changed
> because the original one (which ran quietly) packed up.

Diesel valves do need de-coking quite regularly. I think it just means a polish with grinding paste, which should have been done at the time but was unlikely to; however its arriving with the new part sounds fishy.

[Clive George]

Regularly as in once every million miles or so, if that? I'll admit mine
have only done 200-230K, so haven't had that much time to get coked up yet.

[Mike Tomlinson]

En el artículo <xcbKz.2178551$jB.21...@fx43.am4>, MrCheerful
<g.odon...@yahoo.co.uk> escribió:

>Please enlighten us.

*tumbleweed rolls*

You'll have a long wait; he's off his meds again.

--
(\_/)
(='.'=) systemd: the Linux version of Windows 10
(")_(")

[The Natural Philosopher]

On 09/10/16 03:11, Weatherlawyer wrote:
> On Saturday, 8 October 2016 12:19:41 UTC+1, Chris wrote:
>> On Sat, 08 Oct 2016 10:09:29 +0100, Richard wrote:
>>
>>> Have you just had a VW 'fixed' for the emissions?
>>
>> Nope. Nowt to do with VW, this is a Land Rover. The EMU was changed
>> because the original one (which ran quietly) packed up.
>
> Diesel valves do need de-coking quite regularly.

every 1/4 million miles or so,. yes.

I think it just
> means a polish with grinding paste, which should have been done at
> the time but was unlikely to; however its arriving with the new part
> sounds fishy.
>

--
"Anyone who believes that the laws of physics are mere social
conventions is invited to try transgressing those conventions from the
windows of my apartment. (I live on the twenty-first floor.) "

Alan Sokal

[The Natural Philosopher]

On 08/10/16 19:01, Fredxxx wrote:
> On 08/10/2016 18:46, The Natural Philosopher wrote:

>>> Please tell me why the timing cannot be wrong.
>>

>> Don't change the subject.
>
> Then explain why you say "Do you actually know how the injection timning
> works on a modern diesel" after he said get the timing checked.
>
>> How do you propose anyone 'checks the timing'
>
> Are you suggesting you don't know?
Absolutely. Do you?

[The Natural Philosopher]

On 08/10/16 19:04, Fredxxx wrote:
> On 08/10/2016 18:50, The Natural Philosopher wrote:

>>> The principal of the diesel engine has not changed since it was
>>> invented, it needs correct timing to run properly, and incorrect timing
>>> can wreck it.
>>>
>>> Can you explain what you infer is wrong with these statements?
>>

>> First tell; me what you thing determines the 'timing' on a modern
>> diesel, and how you can 'measure' it, and how you can 'change' it.
>
> We were all hoping you'd be telling where Mr Cheerful statements might
> be wrong.
>
> Do tell...........

HE said 'check the timing' and that implies altering it. I am just
asking how he proposes to do either.

[The Natural Philosopher]

On 08/10/16 19:29, Clive George wrote:
> On 08/10/2016 17:44, The Natural Philosopher wrote:
>> On 08/10/16 17:06, MrCheerful wrote:
>>> On 08/10/2016 16:32, newshound wrote:
>>>> On 10/7/2016 11:53 PM, Chris wrote:
>>>>> Hi all,
>>>>>
>>>>> How is it possible for a diesel engine (given the correct grade of
>>>>> fuel)
>>>>> to pink? Obviously with petrol, you can advance the ignition to
>>>>> produce
>>>>> the effect, but with derv, combustion is determined kind of
>>>>> automatically
>>>>> by the compression level (AFAIK) and is therefore fixed. Yet my diesel
>>>>> car's been pinking since the garage changed the EMU and I'm sure I'm
>>>>> not
>>>>> imagining it. How is that even possible?
>>>>> Any ideas?
>>>>>
>>>>> Ta.
>>>>>
>>>> You need to ask Mr Cheerful, hence the cross post. Might be helpful to
>>>> mention exactly which model Land Rover.
>>>
>>>
>>> The ignition cannot start until the actual moment of injection. So you
>>> first need to get the timing checked. Don't leave it as it can wreck
>>> the engine.
>>
>> Do you actually know how the injection timning works on a modern diesel?
>

> I suspect he does, because he's given the correct answer. If the

> injection starts early, it'll pink. It can start early if the computer

> thinks the crank is in a different position to where it actually is.
>
>

That wasn't what I said.

He said 'check the timing'?

My question was 'how' and 'if its wrong how do you propose to change it'

The point being he doesn't understand how a modern diesel works, if he
thinks there are easy answers to the above.

[The Natural Philosopher]

On 08/10/16 19:37, polygonum wrote:

> On 08/10/2016 19:29, Clive George wrote:
>> It can start early if the computer thinks the crank is in a different
>> position to where it actually is.
>

> Not with you there - how can what the computer thinks affect the
> physical state within the cylinder? The computer could ...

Unbeleivable.

Do you people actually READ what other people write, or its it always
just what you THOUGHT they wrote.

It the crank sensor - or other sensors - is out, the computer will not
have the correct info to compute the correct injection point.

>
> But how do the ECU's thoughts impact on the detonation?
>

*whoosh*

What determines the injection level and timing, if not the EMUS 'thoughts'?

[The Natural Philosopher]

On 08/10/16 19:49, MrCheerful wrote:
>>
>> Do you actually know how the injection timning works on a modern diesel?
>>
>
> Please enlighten us.
>
> The principal of the diesel engine has not changed since it was
> invented, it needs correct timing to run properly, and incorrect timing
> can wreck it.
> Can you explain what you infer is wrong with these statements?
>
> Please tell me why the timing cannot be wrong.

Where did I say that it couldn't?

--
"I guess a rattlesnake ain't risponsible fer bein' a rattlesnake, but ah
puts mah heel on um jess the same if'n I catches him around mah chillun".

[Andy Burns]

Cursitor Doom wrote:

> the *original* diesel engines were (more or less) normally-aspirated,
> were they not? Hence why you can use aerosols like 'Easy Start' to
> get the fuckers going from cold. I wonder if they still make Easy
> Start - anyone know?

Dunno, maybe the new Homebase owners will import his stuff? It was
available over here a few years ago, but doesn't seem to be any more.

<http://www.nulon.com.au/products/aerosols/Start_Ya_Bastard_Instant_Engine_Starter>

[The Natural Philosopher]

On 08/10/16 22:23, NY wrote:
> I'm wondering whether Polygonum (I think, if I've got the quoting
> correct - if not, apologies) thinks that detonation *is* triggered by
> the compression reaching some critical level - in other words, that fuel
> is injected arbitrarily early and then detonates when the pressure
> and/or mixture temperature subsequently reaches the "right" level -
> which is not how it works.

Very old diesels work that way. Fuel-air is compressed and goes bang
under compression.


But not seen it for about 40 years...;-)

[The Natural Philosopher]

Well *diesel* engines for model aircraft ARE diesels and they DO work
that way.

Some old agricultural diesels inject into the inlet manifold

[MrCheerful]

Who mentioned easy??

Do you understand what pinking is? Do you know what are the likely
causes? Do you understand the consequences of ignoring pinking?

Modern diesels work in the same way they have for the last 150 or so
years. The method of timing and controlling the timing has changed.

Tiny model aircraft diesel engines are not the ones under discussion.

There is no mention of what the actual engine type is. Checking the
timing on a diesel may be done merely with a strobe on some engines, or
via computer hookup on others. I would not expect any ordinary person
to have the equipment to do so. The results will determine what course
of action to follow subsequently. Best bet for the OP is to take the
vehicle to a diesel specialist.

[polygonum]

Polygonum was asking how the thoughts of the ECU were translated into
actual events inside the cylinder. On its own, the thoughts of chairman
ECU are nothing. It is what it does with them that matters!

Which you have described.

--
Rod

[Chris Green]

So very old diesel engines had a carburetter of sorts rather than
injectors?

--
Chris Green
·

[NY]

"Cursitor Doom" <cu...@notformail.com> wrote in message
news:ntc0uq$ajh$2...@dont-email.me...

I hadn't realised that diesels had ever been designed that took in fuel and
air mixture (like a petrol engine) and then relied on critical level of
compression/temperature to determine the engine timing. That must have been
a very irregular timing, giving rise to very lumpy running. Would you really
want detonation to occur a long time before TDC (if the engine was very hot)
or a long time after TDC and approaching BDC (if the engine was cold). Seems
very hit and miss.

Did it apply it apply to all non-turbo engines, or just some of the very
early ones?

[Dave Plowman (News)]

In article <8499a0b1-e7f1-4b8a...@googlegroups.com>,

Weatherlawyer <Weathe...@gmail.com> wrote:
> Diesel valves do need de-coking quite regularly.

Eh? Don't know of any modern engine that needs de-coking regularly. Think
this was more a function of older oils anyway.

--
*Being healthy is merely the slowest possible rate at which one can die.

[Dave Plowman (News)]

In article <e2cpcd-...@esprimo.zbmc.eu>,

Chris Green <c...@isbd.net> wrote:
> > it used to be how it worked donkey's years ago, though. In a normally-
> > aspirated diesel engine (they don't make 'em any more 'cos they're
> > shite) the diesel is sucked in along with air and spontaneously
> > combusts when the compression level and cylinder temperature reach a
> > certain point. But I don't think they've been made that way for
> > decades now.

> So very old diesel engines had a carburetter of sorts rather than
> injectors?

It's not even strictly true. Direct injection diesel engines have been
around for at least 80 years.

--
*It ain't the size, it's... er... no, it IS ..the size.

[The Natural Philosopher]

Model aircraft diesels still do.

And a compression adjustment screw for ignition timing.


However the diesel I am tyhi8nking of - 60s tractor, seemed to have
injection,but it wasn't into the cylinders. Into the manifold.


And of course in between are indirection injection, which is not exactly
into the cylinders, either.

http://www.dieselhub.com/tech/idi-vs-di.html



--
“Some people like to travel by train because it combines the slowness of
a car with the cramped public exposure of 
an airplane.”

Dennis Miller

[The Natural Philosopher]

On 09/10/16 09:00, MrCheerful wrote:
> Checking the timing on a diesel may be done merely with a strobe on some
> engines, or via computer hookup on others.

Ok' I'll bite.

What do you hook the strobe up to - an injector?

What about multi-injection engines?

What is the relationship between actual ignition time, fuel-air ratio,
combustion pressure, engine temperature, given a certain injection time?

Or are all these mere handwaved away?

A little knowledge makes you look stupid,


--
"Socialist governments traditionally do make a financial mess. They
always run out of other people's money. It's quite a characteristic of them"

Margaret Thatcher

[Dave Plowman (News)]

In article <55cc4d8...@davenoise.co.uk>,

Dave Plowman (News) <da...@davenoise.co.uk> wrote:
> In article <e2cpcd-...@esprimo.zbmc.eu>,
> Chris Green <c...@isbd.net> wrote:
> > > it used to be how it worked donkey's years ago, though. In a normally-
> > > aspirated diesel engine (they don't make 'em any more 'cos they're
> > > shite) the diesel is sucked in along with air and spontaneously
> > > combusts when the compression level and cylinder temperature reach a
> > > certain point. But I don't think they've been made that way for
> > > decades now.

> > So very old diesel engines had a carburetter of sorts rather than
> > injectors?

> It's not even strictly true. Direct injection diesel engines have been
> around for at least 80 years.

If I remember things right (my father worked in the truck industry, but I
had no real interest in diesel engines) indirect injection gives a
slightly more refined result. Early direct injection engines were very
efficient, but agricultural.

The advent of electronic injectors and very high fuel rail pressure made
direct injection the way to go these days - while giving acceptable
refinement for car use. And I've a feeling some engines use a mixture of
both.

--
*It's this dirty because I washed it with your wife's knickers*

[Fredxxx]

No it doesn't.

If conventional pump there is kit to measure timing, Ross-Tech do a
plugin. You can still have drive by wire on a conventional pump which
can calculate injection quantity based on load, turbo etc.

For common rail the timing is dependent on various temperatures, crank
speeds, various pressures and load demand. It's important the pressure
is limited to ensure damage to pistons, rods etc. An "injection" can be
a number of separate events, I recall 5 being mentioned on one system. I
would expect this information can be generally gleamed from an ECU
diagnostic port.

The OP hasn't come back to say the type of system he has. ECUs may also
be different for different levels of tune, or certainly mapped
differently. I know the Duratorq engine has different injectors for its
range of power outputs on essentially the same engine. For all I know
the 'wrong' ECU has been fitted.

[Fredxxx]

Its funny how Diesel stole the limelight when there were various patents
that predate his work.

Most model airplane engines are akin to hot bulb, and are not truly
compression ignition.

> Some old agricultural diesels inject into the inlet manifold

Can you provide an example? Even semi-diesels / hot bulb diesels use low
pressure injection.

[The Natural Philosopher]

On 09/10/16 12:05, Fredxxx wrote:
> If conventional pump there is kit to measure timing, Ross-Tech do a
> plugin. You can still have drive by wire on a conventional pump which
> can calculate injection quantity based on load, turbo etc.
>
> For common rail the timing is dependent on various temperatures, crank
> speeds, various pressures and load demand. It's important the pressure
> is limited to ensure damage to pistons, rods etc. An "injection" can be
> a number of separate events, I recall 5 being mentioned on one system. I
> would expect this information can be generally gleamed from an ECU
> diagnostic port.

But not a 'strobe'

At least you understand the complexity. Its almost certain that the
engine is running slightly off because its not been connected back to
some sensor. OR there is a faulty sensor. If et ECU was needing to be
changed it may be whatever broke it, broke the sensor too,


"Checking the timing" is pointless as there is no way to change it
directly... If the engine is pinking, more than normal diesel clatter,
the timing or fuel air mixture is wrong. Measuring it wont help fix it.

What is needed is to check all the diagnostics and see if there is a
sensor fault.


--
To ban Christmas, simply give turkeys the vote.

[Fredxxx]

On 09/10/2016 02:12, Clive George wrote:

> On 08/10/2016 23:39, Bob Eager wrote:
>
>>> But how do the ECU's thoughts impact on the detonation?
>>

>> Because the detonation is caused not by compression ignition these days,
>> but by the injector timing.
>
> It always was injector timing. These days the injectors are controlled
> electrically, but they were mechanical in the past - the diesel pump was
> a timed device, sending a pulse of fuel to each injector at the
> appropriate time.

That's not strictly true for all.
https://en.wikipedia.org/wiki/Hot-bulb_engine#1890s.E2.80.931910

What is interesting is that glow plugs are sometimes hot just to reduce
emissions. Sort of getting close to a hot bulb engine!

[Fredxxx]

On 09/10/2016 06:57, The Natural Philosopher wrote:
> On 08/10/16 19:49, MrCheerful wrote:
>>>
>>> Do you actually know how the injection timning works on a modern diesel?
>>>
>>
>> Please enlighten us.
>>
>> The principal of the diesel engine has not changed since it was
>> invented, it needs correct timing to run properly, and incorrect timing
>> can wreck it.
>> Can you explain what you infer is wrong with these statements?
>>
>> Please tell me why the timing cannot be wrong.
>
> Where did I say that it couldn't?

The implication by abusing Mr Cheerful is that it can't be wrong.

Is this reply your way of accepting you could be wrong and Mr Cheerful's
post was appropriate for the information at hand?

[Tim Lamb]

In message <55cc4d8...@davenoise.co.uk>, "Dave Plowman (News)"
<da...@davenoise.co.uk> writes

>In article <e2cpcd-...@esprimo.zbmc.eu>,
> Chris Green <c...@isbd.net> wrote:
>> > it used to be how it worked donkey's years ago, though. In a normally-
>> > aspirated diesel engine (they don't make 'em any more 'cos they're
>> > shite) the diesel is sucked in along with air and spontaneously
>> > combusts when the compression level and cylinder temperature reach a
>> > certain point. But I don't think they've been made that way for
>> > decades now.
>
>> So very old diesel engines had a carburetter of sorts rather than
>> injectors?
>
>It's not even strictly true. Direct injection diesel engines have been
>around for at least 80 years.

Umm.. Don't know how the single cylinder Marshall tractor of my youth
worked. Starting was hand crank with either cartridge or glowing
corrugated cardboard:-)

More recently agricultural diesels have changed from indirect to direct
injection (I think) Something to do with bowl in piston from offset
chamber.
>

--
Tim Lamb

[The Natural Philosopher]

Please read what I wrote. I am not talking about glowplug engines, but
'diesels'.


They run on paraffin and ether, plus oil as they are 2-wstrokes.

https://www.youtube.com/watch?v=uhJH0c7igig

>> Some old agricultural diesels inject into the inlet manifold
>
> Can you provide an example? Even semi-diesels / hot bulb diesels use low
> pressure injection.

I've been looking, but can only find indirect injection examples

It was a long time ago...maybe the one I saw was indirect, just the the
injectors weren't straight into the cylinders.

[The Natural Philosopher]

No.

You and mr cheerful seem to be under the false impression that I
criticised his post on the grounds of being wrong.

It was on te grounds of being stupid. Not wrong

I.e.

Like 'Oh, my hamster has died" "You had better check is blood pressure"

What is 'pinking'?

IT'S PRE-IGNITION, DUH!

But there isn't, on a diesel any 'timing' you can measure or alter. It
is a complex result of many calculations performed by the EMU depending
on the input from its sensors. That determines *injection* timing, but
it doesn't determine *ignition* timing, as there are then things like
flame propagation rates and so on before you get to peak cylinder
pressure, which is probably the nearest parameter that corresponds to
'timing'. And that is affected by fuel amount mixing ratio and air
temperature and so on.

None of which you can 'measure'. Not without gear even a top garage wont
have. And in-cylinder sensors.

Since Mr Cheerful didn't seem to understand any of that, I asked him if
he actually knew how a modern diesel works.

It appears he doesn't.

You seem to, a little, but you haven't caught the original point.
Measuring whatever you think is 'timing', on a diesel is almost
impossible to do to any level of accuracy, and almost completely
pointless when you have.

You can't rotate the distributor to 'fix' it. There isn't one.

You can look at where the injectors are firing if you want, but that
doesn't tell you any more than that is when they are firing, Maybe they
are firing too early. Maybe they are firing too weak..
The EMU will tell you that.

And tell you if any sensors are out of spec. Or you may have to guess at
which one is faulty. e.g. it might be that a temperature sensor appears
OK, but isn't sensing inlet air temperatures correctly.

We so far don't know what the diesel type is, and we don't know what led
up to the EMU being changed. If the engine was running good and not
pinking before, why was the EMU changed.

E.g. my boiler started leaking, and before it could get fixed, it
stopped firing, but the air and fuel pumps would run indefinitely. Then
it fired, but went into lockout and wouldnt run at all.

There turned out to be three distinct faults which all had occurred
either one because of te other, or purely concentrically.

It was leaking. It was soaked in te combustion chamber and the wire to
the photocell had corroded and was sometimes touching, sometimes not.
Ther was an issue with the fuel solenoid I think.

The sensor and the control box were changed, but it wasn't till the
solenoid was fiddled with that it all sprang to life

The moral is that sometimes fixing one thing reveals a problem elsewhere
that was masked.



--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

[Cursitor Doom]

On Sun, 09 Oct 2016 06:58:29 +0100, Andy Burns wrote:

> <http://www.nulon.com.au/products/aerosols/
Start_Ya_Bastard_Instant_Engine_Starter>

Only in Australia. ;-)

[Cursitor Doom]

On Sun, 09 Oct 2016 13:19:04 +0100, The Natural Philosopher wrote:
>
> Like 'Oh, my hamster has died" "You had better check is blood pressure"

Now. Just. A. Minute., NP.

Are you now claiming that it's a waste of time to check the blood
pressure of a dead hamster?
Some clarification required here.

[NY]

"The Natural Philosopher" <t...@invalid.invalid> wrote in message
news:ntdcjk$vjt$1...@news.albasani.net...

> You seem to, a little, but you haven't caught the original point.
> Measuring whatever you think is 'timing', on a diesel is almost impossible
> to do to any level of accuracy, and almost completely pointless when you
> have.
>
> You can't rotate the distributor to 'fix' it. There isn't one.

True, but then nor can you make any comparable adjustment with a modern
petrol engine. In both cases, timing is determined (at least in part) by
sensors such as crankshaft position, with timing offsets controlled partly
by non-adjustable algorithm behaviour in the ECU and (maybe) partly by
tweaking parameters in the ECU. It is the latter which is the nearest
equivalent to rotating the distributor.

Did old non-ECU have any equivalent of rotating the distributor on a petrol
engine - for example, to alter the timing of the mechanical fuel injectors
relative to TDC.

I take you point about timing of *ignition* in a diesel being a bit less
precise than in a petrol engine, because it doesn't happen precisely when
the spark of a petrol engine triggers it, but is subject to extra
uncertainty about the delay between injection beginning and detonation
beginning. Presumably there are sensors in the cylinder head which can sense
the delay between the two at any instant and can adjust the injector timing
accordingly so the detonation occurs exactly when it is wanted - ie it
compensates for the variable injection-to-detonation delay.


I really must read up about indirect injection and try to understand how it
works. The simplified "Ladybird book" diagrams/explanations for petrol and
diesel engines always show (for a diesel) fuel being injected directly into
the cylinder, not into an ante-chamber or manifold. When I first heard about
cars having direct injection, as if it was a new innovation, I was left
thinking "but what other sort is there"?

Why is it that my first diesel car, a 1997 Peugeot with a 1.9 TD (not HDi)
engine, usually needed a pause between turning on the ignition and the
engine firing when the starter is turned on, whereas my newer cars (Peugeot
2.0 and 1.6 HDi engines) don't require a delay: you can turn the key
straight to starter motor and the engine will fire immediately. Presumably
the delay in the older engine was for glow plugs to heat up the cylinder to
the operating temperature that is normally caused by the previous
combustions, but why do HDi engines not need this to occur, or at least heat
up so quickly that you don't have to allow for it?

[Cursitor Doom]

On Sun, 09 Oct 2016 13:19:04 +0100, The Natural Philosopher wrote:

> We so far don't know what the diesel type is, and we don't know what led
> up to the EMU being changed. If the engine was running good and not
> pinking before, why was the EMU changed.

I'm pretty sure he has said somewhere that it just simply conked out one
day.
You seem to be jolly clever with this diesel malarky, NP. Let's say the
OP could insert some sort of delay line in the injector leads so when an
actuation pulse comes down the wire, it can be momentarily 'held' by an
adjustable interval to correct this pre-ignition (if that's what it is).
Would that be viable? Obviously you'd have to do this by the same delay
for each injector control wire. Or how about a similar arrangement for
the crankshaft position sensor - only requires one intervention rather
than several. Just a thought....

[Cursitor Doom]

On Sun, 09 Oct 2016 02:12:58 +0100, Clive George wrote:

> It always was injector timing. These days the injectors are controlled
> electrically, but they were mechanical in the past - the diesel pump was
> a timed device, sending a pulse of fuel to each injector at the
> appropriate time.

That was before the introduction of common-rail injection systems,
though, n'est pas? The good old days when everything was simpler.

[Cursitor Doom]

On Sun, 09 Oct 2016 09:34:54 +0100, Chris Green wrote:

> So very old diesel engines had a carburetter of sorts rather than
> injectors?

Nope. Certainly not in the conventionally accepted sense.

[Cursitor Doom]

On Sun, 09 Oct 2016 10:09:23 +0100, NY wrote:

> Did it apply it apply to all non-turbo engines, or just some of the very
> early ones?

*Very* early designs. I'm giving my age away now. ;-)

[Cursitor Doom]

On Sun, 09 Oct 2016 09:00:28 +0100, MrCheerful wrote:

> Best bet for the OP is to take the
> vehicle to a diesel specialist.

Yeah, like good advice 20 years ago. Today you pretty much have to go to
someone who specialises in the particular engine and EMU so therefore has
the hardware interfaces and software for that specific model.

[Cursitor Doom]

On Sun, 09 Oct 2016 12:00:12 +0100, The Natural Philosopher wrote:

> Ok' I'll bite.
>
> What do you hook the strobe up to - an injector?

I was wondering that, too.

[Fredxxx]

On 09/10/2016 12:14, The Natural Philosopher wrote:
> On 09/10/16 12:05, Fredxxx wrote:
>> If conventional pump there is kit to measure timing, Ross-Tech do a
>> plugin. You can still have drive by wire on a conventional pump which
>> can calculate injection quantity based on load, turbo etc.
>>
>> For common rail the timing is dependent on various temperatures, crank
>> speeds, various pressures and load demand. It's important the pressure
>> is limited to ensure damage to pistons, rods etc. An "injection" can be
>> a number of separate events, I recall 5 being mentioned on one system. I
>> would expect this information can be generally gleamed from an ECU
>> diagnostic port.
>
> But not a 'strobe'
>
> At least you understand the complexity. Its almost certain that the
> engine is running slightly off because its not been connected back to
> some sensor. OR there is a faulty sensor. If et ECU was needing to be
> changed it may be whatever broke it, broke the sensor too,
>
>
> "Checking the timing" is pointless as there is no way to change it
> directly... If the engine is pinking, more than normal diesel clatter,
> the timing or fuel air mixture is wrong. Measuring it wont help fix it.

Are you being deliberately stupid?

We don't know what pump he has, as I have seen on many occasions is a
conventional pump with a drive by wire fuel control. The timing is done
by the pump itself and can only be checked through conventional means.

Being a Landrover, it is more like to be old rather than new. Saying
something out of the blue "Do you actually know how the injection
timning works on a modern diesel?" is entirely irrelevant and insincere.

> What is needed is to check all the diagnostics and see if there is a
> sensor fault.

Assuming it has a sensor related to injection timing. In true form you
are being very presumptuous.

[Dave Plowman (News)]

In article <tj8+O4IN...@marfordfarm.demon.co.uk>,

Tim Lamb <t...@marfordfarm.demon.co.uk> wrote:
> >It's not even strictly true. Direct injection diesel engines have been
> >around for at least 80 years.

> Umm.. Don't know how the single cylinder Marshall tractor of my youth
> worked. Starting was hand crank with either cartridge or glowing
> corrugated cardboard:-)

> More recently agricultural diesels have changed from indirect to direct
> injection (I think) Something to do with bowl in piston from offset
> chamber.

Albion were one that used direct injection for diesel engines long before
WW2. Most usually four cylinder units for trucks.

--
*Puritanism: The haunting fear that someone, somewhere may be happy.

[Cursitor Doom]

On Sun, 09 Oct 2016 14:05:04 +0100, NY wrote:

> Why is it that my first diesel car, a 1997 Peugeot with a 1.9 TD (not
> HDi) engine, usually needed a pause between turning on the ignition and
> the engine firing when the starter is turned on, whereas my newer cars
> (Peugeot 2.0 and 1.6 HDi engines) don't require a delay: you can turn
> the key straight to starter motor and the engine will fire immediately.
> Presumably the delay in the older engine was for glow plugs to heat up
> the cylinder to the operating temperature that is normally caused by the
> previous combustions, but why do HDi engines not need this to occur, or
> at least heat up so quickly that you don't have to allow for it?

Good question. I've often wondered about that as well. :-/

[Fredxxx]

OK.

> They run on paraffin and ether, plus oil as they are 2-wstrokes.
>
> https://www.youtube.com/watch?v=uhJH0c7igig
>
>>> Some old agricultural diesels inject into the inlet manifold
>>
>> Can you provide an example? Even semi-diesels / hot bulb diesels use low
>> pressure injection.
>
> I've been looking, but can only find indirect injection examples
>
> It was a long time ago...maybe the one I saw was indirect, just the the
> injectors weren't straight into the cylinders.

The only ones I have seen are into a hot bulb. I have never seen one you
talk of.

Even this wiki article says the model airplane engine doesn't scale up.
https://en.wikipedia.org/wiki/Model_engine

[Chris]

On Sun, 09 Oct 2016 14:43:51 +0100, Fredxxx wrote:

> Being a Landrover, it is more like to be old rather than new.

Certainly is a lot closer to old than new! It's a 2003 TD5 (the TD5 is a
BMW engine).

[The Natural Philosopher]

On 09/10/16 14:05, NY wrote:
> "The Natural Philosopher" <t...@invalid.invalid> wrote in message
> news:ntdcjk$vjt$1...@news.albasani.net...
>> You seem to, a little, but you haven't caught the original point.
>> Measuring whatever you think is 'timing', on a diesel is almost
>> impossible to do to any level of accuracy, and almost completely
>> pointless when you have.
>>
>> You can't rotate the distributor to 'fix' it. There isn't one.
>
> True, but then nor can you make any comparable adjustment with a modern
> petrol engine. In both cases, timing is determined (at least in part) by
> sensors such as crankshaft position, with timing offsets controlled
> partly by non-adjustable algorithm behaviour in the ECU and (maybe)
> partly by tweaking parameters in the ECU. It is the latter which is the
> nearest equivalent to rotating the distributor.
>

Well I wouldn't advocate 'measuring te timing in a modern petrol engine,
either...

> Did old non-ECU have any equivalent of rotating the distributor on a
> petrol engine - for example, to alter the timing of the mechanical fuel
> injectors relative to TDC.

I believe they MAY have done on mecahnical injectors, but thats REALLY
old school

>
> I take you point about timing of *ignition* in a diesel being a bit less
> precise than in a petrol engine, because it doesn't happen precisely
> when the spark of a petrol engine triggers it, but is subject to extra
> uncertainty about the delay between injection beginning and detonation
> beginning. Presumably there are sensors in the cylinder head which can
> sense the delay between the two at any instant and can adjust the
> injector timing accordingly so the detonation occurs exactly when it is
> wanted - ie it compensates for the variable injection-to-detonation delay.
>
>
> I really must read up about indirect injection and try to understand how
> it works. The simplified "Ladybird book" diagrams/explanations for
> petrol and diesel engines always show (for a diesel) fuel being injected
> directly into the cylinder, not into an ante-chamber or manifold. When I
> first heard about cars having direct injection, as if it was a new
> innovation, I was left thinking "but what other sort is there"?
>
> Why is it that my first diesel car, a 1997 Peugeot with a 1.9 TD (not
> HDi) engine, usually needed a pause between turning on the ignition and
> the engine firing when the starter is turned on, whereas my newer cars
> (Peugeot 2.0 and 1.6 HDi engines) don't require a delay: you can turn
> the key straight to starter motor and the engine will fire immediately.
> Presumably the delay in the older engine was for glow plugs to heat up
> the cylinder to the operating temperature that is normally caused by the
> previous combustions, but why do HDi engines not need this to occur, or
> at least heat up so quickly that you don't have to allow for it?

I have a BMW diesel in a freelander, and that WILL start after a few
cranks from cold, but with a lot of smoke. If I wait till the glowplug
lights go out, it starts quicker with a lot less smoke.



--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

[The Natural Philosopher]

On 09/10/16 14:09, Cursitor Doom wrote:
> On Sun, 09 Oct 2016 13:19:04 +0100, The Natural Philosopher wrote:
>>
>> Like 'Oh, my hamster has died" "You had better check is blood pressure"
>
> Now. Just. A. Minute., NP.
>
> Are you now claiming that it's a waste of time to check the blood
> pressure of a dead hamster?

Well yes, I think I am.

If restoring it to life is the aim.


> Some clarification required here.
>


--
"What do you think about Gay Marriage?"
"I don't."
"Don't what?"
"Think about Gay Marriage."

[The Natural Philosopher]

Its called software and its in the ECU.

Look the whole point is simply this. ALL the timing depends on the
software and the sensors. With a new EMU one may assume the software
works. Ergo one or more sensors have probably not been reattached.Or are
faulty

Its unlikely to be a failing crank sensor, as these tend to work, or not
work, and if not working should throw an error code.

It COULD be an analogue sensor, like air temperature or airflow meter or
somesuch, that isn't changing as it should but is still outsize 'fault
parameters' when the ECU checks it.

WE don't even know if its a turbodiesel or not.

Lots more sensors on those.

[The Natural Philosopher]

On 09/10/16 14:43, Fredxxx wrote:
> On 09/10/2016 12:14, The Natural Philosopher wrote:
>> On 09/10/16 12:05, Fredxxx wrote:
>>> If conventional pump there is kit to measure timing, Ross-Tech do a
>>> plugin. You can still have drive by wire on a conventional pump which
>>> can calculate injection quantity based on load, turbo etc.
>>>
>>> For common rail the timing is dependent on various temperatures, crank
>>> speeds, various pressures and load demand. It's important the pressure
>>> is limited to ensure damage to pistons, rods etc. An "injection" can be
>>> a number of separate events, I recall 5 being mentioned on one system. I
>>> would expect this information can be generally gleamed from an ECU
>>> diagnostic port.
>>
>> But not a 'strobe'
>>
>> At least you understand the complexity. Its almost certain that the
>> engine is running slightly off because its not been connected back to
>> some sensor. OR there is a faulty sensor. If et ECU was needing to be
>> changed it may be whatever broke it, broke the sensor too,
>>
>>
>> "Checking the timing" is pointless as there is no way to change it
>> directly... If the engine is pinking, more than normal diesel clatter,
>> the timing or fuel air mixture is wrong. Measuring it wont help fix it.
>
> Are you being deliberately stupid?
>
> We don't know what pump he has, as I have seen on many occasions is a
> conventional pump with a drive by wire fuel control. The timing is done
> by the pump itself and can only be checked through conventional means.

I don't think that layout would *have* an 'EMU'

>
> Being a Landrover, it is more like to be old rather than new. Saying
> something out of the blue "Do you actually know how the injection
> timning works on a modern diesel?" is entirely irrelevant and insincere.
>

WEll I have had diesel landrovers for the last 20 years and non of them
are as you describe. The old defneder 4 pot, then te TD4, aqnd tre BMW
TD4 unit are all electronic.

>> What is needed is to check all the diagnostics and see if there is a
>> sensor fault.
>
> Assuming it has a sensor related to injection timing. In true form you
> are being very presumptuous.

Well yes, I am presuming that the OP and you are not so completely
moronic as to check the sensor for the ABS, in an effort to resolve
pinking in the diesel.

If that is an assumption too far, I apologise, but possibly, if you are
that stupid, you shouldn't be allowed near a fuel injection system.


--
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"

[ne...@loampitsfarm.co.uk]

On Sun, 09 Oct 2016 12:01:55 +0100, "Dave Plowman (News)"
<da...@davenoise.co.uk> wrote:

>If I remember things right (my father worked in the truck industry, but I
>had no real interest in diesel engines) indirect injection gives a
>slightly more refined result. Early direct injection engines were very
>efficient, but agricultural.

That's right, lorry and tractor engines tended to be direct injection
but the rapid rise in pressure as the atomised fuel burnt gave them
the harsh knock but it wasn't the same as pinking.

So passenger vehicles injected the spray into a swirl chamber (Ricardo
invention I think) the partially burned fuel air mixture then exited
into the cylinder to complete combustion and this meant the pressure
rise was smoother. The drawback was that the combustion continued as
the piston descended , so some of the heat expanded from a lower
pressure, hence less thermodynamic efficiency.
>
>The advent of electronic injectors and very high fuel rail pressure made
>direct injection the way to go these days - while giving acceptable
>refinement for car use. And I've a feeling some engines use a mixture of
>both.

Common rail with the higher pressure leads to finer fuel droplets and
faster switching of the injectors than a piston pumping fuel past a
injector poppet valve, so a short squirt at around TDC can initiate
combustion and then the main charge is squirted in once a flame front
has developed, giving a smoother pressure rise and complete combustion
near the top of the stroke, moving the diesel cycle into the realms of
the Otto cycle whilst keeping the volumetric efficiency of the diesel
at part throttle. This still isn't as ideal as a constant volume
combustion but the higher compression ratio and volumetric efficiency
still give it the edge.

AJH

[Tim Lamb]

In message <ntduip$3ch$2...@news.albasani.net>, The Natural Philosopher
<t...@invalid.invalid> writes

>On 09/10/16 14:05, NY wrote:
>> "The Natural Philosopher" <t...@invalid.invalid> wrote in message
>> news:ntdcjk$vjt$1...@news.albasani.net...
>>> You seem to, a little, but you haven't caught the original point.
>>> Measuring whatever you think is 'timing', on a diesel is almost
>>> impossible to do to any level of accuracy, and almost completely
>>> pointless when you have.
>>>
>>> You can't rotate the distributor to 'fix' it. There isn't one.
>>
>> True, but then nor can you make any comparable adjustment with a modern
>> petrol engine. In both cases, timing is determined (at least in part) by
>> sensors such as crankshaft position, with timing offsets controlled
>> partly by non-adjustable algorithm behaviour in the ECU and (maybe)
>> partly by tweaking parameters in the ECU. It is the latter which is the
>> nearest equivalent to rotating the distributor.
>>
>
>Well I wouldn't advocate 'measuring te timing in a modern petrol
>engine, either...
>
>
>> Did old non-ECU have any equivalent of rotating the distributor on a
>> petrol engine - for example, to alter the timing of the mechanical fuel
>> injectors relative to TDC.
>
>I believe they MAY have done on mecahnical injectors, but thats REALLY
>old school

The injector pump had rotating weights which altered the injection point
relative to engine speed or fuel quantity or both. Beyond my knowledge.

I once set the injector pump timing on an ancient David Brown tractor.
The sort you see towing the bomb trolleys in WW2 RAF films. There were
timing marks on the gear train and I think the pump had to be arranged
for the fuel *spill* point to be a few deg. before TDC.

Tim Lamb

[Clive George]

On 09/10/2016 14:05, NY wrote:

> I really must read up about indirect injection and try to understand how
> it works. The simplified "Ladybird book" diagrams/explanations for
> petrol and diesel engines always show (for a diesel) fuel being injected
> directly into the cylinder, not into an ante-chamber or manifold. When I
> first heard about cars having direct injection, as if it was a new
> innovation, I was left thinking "but what other sort is there"?
>
> Why is it that my first diesel car, a 1997 Peugeot with a 1.9 TD (not
> HDi) engine, usually needed a pause between turning on the ignition and
> the engine firing when the starter is turned on, whereas my newer cars
> (Peugeot 2.0 and 1.6 HDi engines) don't require a delay: you can turn
> the key straight to starter motor and the engine will fire immediately.
> Presumably the delay in the older engine was for glow plugs to heat up
> the cylinder to the operating temperature that is normally caused by the
> previous combustions, but why do HDi engines not need this to occur, or
> at least heat up so quickly that you don't have to allow for it?

Your XUD engine had little inserts in the cylinder head where the fuel
injector and glowplugs go. They make a little chamber away from the
piston head. Hence indirect. The injector on the HDi goes straight into
the main chamber - direct.

A friend had a little rattling in a XUD which swiftly turned into a
stopped engine - the insert in one of the cylinders had fallen out, and
having the piston bash it against the head top leads to a big mess very
quickly. I've not heard of that happening to anybody else though.

The fuel pressure on the direct injection one is way higher - at least
10x. Which means tinier droplets, which means easier to burn, which
means easier to start - no need for the glow plugs.

[The Natural Philosopher]

Well you haven't attended many aeromodelling shows then.

And the video shows one being started and run, so its not fiction.
I've owned half a dozen in my youth, and they are still being made today.

In fact I think that you CAN scale what you call 'hot bulb' (gloplug)
engines up, and in fact a lot of diesels may or may not use the
assistance of glow plugs even after they have started. I don't know. BUT
(some of) the paraffin engines of yore are very much akin to scaled up
'gloplug' engines. although they tend to be 4-strokes.

Gas engines used hot ceramic gloplugs too.

All forms of ignition have been tried. What's left is what worked best
in any given application

> Even this wiki article says the model airplane engine doesn't scale up.
> https://en.wikipedia.org/wiki/Model_engine

NO it doesn't.



--
"When a true genius appears in the world, you may know him by this sign,
that the dunces are all in confederacy against him."

Jonathan Swift.