Hi mchel
I think your problem with stabilizing rpm on the bench is due to the pantone.
the more you increase the load and the more efficient the reactor, so the turns go up the following power (torque x nb of tr = power);
The tests I did (without bench; with a nice straight line of 6km); I learned that it was very difficult to stay at constant speed under heavy load. as soon as the pantone is at 100/100 the vehicle accelerates so I gently lift my foot. And there lost the vehicle continues to a critical point where the performance of the pantone drops; then must reaccelerate like a deaf man to restart everything. Not good
So now I let it run without changing the position of the accelerator and when the speed is done making the yoyo I adjust
@+
PS: Laurent still has his 13 key, will have to pay him a 33 bolt
Mercedes 240 D from Didier
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- Éconologue good!
- posts: 406
- Registration: 08/01/07, 11:43
- Location: South West
I remain skeptical about the knocking aspect of the piston on the shirt ... Let me explain!
There are three accelerometers placed in the piston translation alignment and an accelerometer placed on the engine block, perpendicular to the displacements of the pistons.
We can clearly see the shocks caused by the explosion of the fuel in the different cylinders (see spectra of higher amplitudes) thanks to the vertical accelerometers.
However, if we look more closely with the spectrum of the engine block, we can see that there is an inconsistency: the vibrations of the engine block are not in adequacy with the vibrations detected by the others. We see that the vibration of the engine block is greater during the explosion in chambers 1 and 3 and less significant (or even zero) in chambers 2 and 4. Beginning of charging? !!! Yes No?! Or, is it due to a synchronous return of the inertia of the load ?! To have...
Consequently, it can be said that only one component in the direction of displacement of the pistons generates this new peak present after combustion.
Now it remains to be seen where it could come from.
Hypotheses...
Does the engine rattle ?! So it may well be a back burn from the end of the mix.
Otherwise, could it not be a force feedback due to the inertia of the load to be driven ?!
Is this something else to determine ?!
In view of the spectrum of piston 1, it is certain that the pantone smoothes this post-combustion curve. But the peak on cylinder 2 moderates our assertion regarding this smoothing ...
Thus, I think that we should push further the observations of these spectra while looking more closely at the design of the vehicle engine and its operation: intake, engine design, adjustments ...
What do you think?!
There are three accelerometers placed in the piston translation alignment and an accelerometer placed on the engine block, perpendicular to the displacements of the pistons.
We can clearly see the shocks caused by the explosion of the fuel in the different cylinders (see spectra of higher amplitudes) thanks to the vertical accelerometers.
However, if we look more closely with the spectrum of the engine block, we can see that there is an inconsistency: the vibrations of the engine block are not in adequacy with the vibrations detected by the others. We see that the vibration of the engine block is greater during the explosion in chambers 1 and 3 and less significant (or even zero) in chambers 2 and 4. Beginning of charging? !!! Yes No?! Or, is it due to a synchronous return of the inertia of the load ?! To have...
Consequently, it can be said that only one component in the direction of displacement of the pistons generates this new peak present after combustion.
Now it remains to be seen where it could come from.
Hypotheses...
Does the engine rattle ?! So it may well be a back burn from the end of the mix.
Otherwise, could it not be a force feedback due to the inertia of the load to be driven ?!
Is this something else to determine ?!
In view of the spectrum of piston 1, it is certain that the pantone smoothes this post-combustion curve. But the peak on cylinder 2 moderates our assertion regarding this smoothing ...
Thus, I think that we should push further the observations of these spectra while looking more closely at the design of the vehicle engine and its operation: intake, engine design, adjustments ...
What do you think?!
0 x
ThierrySan wrote:I remain skeptical about the knocking aspect of the piston on the shirt ... Let me explain!
[...]
Does the engine rattle ?! So it may well be a back burn from the end of the mix.
Otherwise, could it not be a force feedback due to the inertia of the load to be driven ?!
Is this something else to determine ?!
[...]
Thus, I think that we should push further the observations of these spectra while looking more closely at the design of the vehicle engine and its operation: intake, engine design, adjustments ...
What do you think?!
Hi to you all !
symaptic dosument this analysis ... I read it last night, but I was a little disappointed because there is a big part on the inductive sensor and a small on the accelerometers, which left me on the hunger
it is a very objective analysis of the results which lets us formulate the hypotheses that we can stick to it
for noise reduction, this will be confirmed by the synchronous averages of instantaneous speeds ... a lower amplitude reflecting a less violent shock during the explosion in the room ????!?
for the story of this second peak (red bubble) I am perplexed .... I want the engine to be old .. but from there to have a game so important that it knocks ... in my opinion (which is not at all an exact science ) the engine will already have been torn apart by dint of beating and vibrating in all directions .... no?!?
I quite agree with what Thierry says ... or a post combustion:
-> first normal explosion, then a second due to the presence of the doping gas (ionized vapor?) ...
otherwise it is due to inertia finally I do not really see what you (Thierry) meant by that ... me I interpreted:
-> it is the elastic return of the material, all the parts compressed during the explosion which restore this deformation energy (a bit like a spring) ...
voalou ... these are only my impressions ...
otherwise I don't want to sound unpleasant, because you've all done a lot of work ... but 5 pages out of 20 for accelerometers ... it's a bit short
I quote : "The synchronous variances of accelerometric signals are rich in information."
HAAAA I want to know more
@ + michel and the others
0 x
"To do something is expensive, to do nothing will cost much more." Koffie Annan
next species endangered: Man ... and it will be good for him !!!
MAN IS A VERY DANGEROUS POLLUTION NATURAL!
next species endangered: Man ... and it will be good for him !!!
MAN IS A VERY DANGEROUS POLLUTION NATURAL!
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- Éconologue good!
- posts: 406
- Registration: 08/01/07, 11:43
- Location: South West
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- I understand econologic
- posts: 168
- Registration: 13/08/05, 17:49
Good evening,
for the second pic on page 17, maybe it's the shock of the cam heads when it comes into contact with the pusher? (slightly confirm in the angular domain) ...
Or a gear problem ...
On the other hand (page 7) it is strange to note that the background noise of the spectral density is higher with the pantone than without the pantone, right? everyone says and finds (including me) that doping with water reduces noise (therefore mechanical vibrations) or there, we see that they are higher.
Hence my question to Mathieu ... would there have been no inversion of the data before analysis? Under Matlab or Scilab this can happen easily.
So much so that the resonance (of a bearing probably) visible around 11000hz almost disappears in the noise. Maybe there was a filtering out?
On the spectrum without pantone we can I think, to distinguish a comb of stripes can be due to a sick bearing precisely. Difficult to say without an analysis of the signal with the characteristics of the bearing (if it exists).
Does page 15 indicate a loss of compression on cylinder 3?
for the second pic on page 17, maybe it's the shock of the cam heads when it comes into contact with the pusher? (slightly confirm in the angular domain) ...
Or a gear problem ...
On the other hand (page 7) it is strange to note that the background noise of the spectral density is higher with the pantone than without the pantone, right? everyone says and finds (including me) that doping with water reduces noise (therefore mechanical vibrations) or there, we see that they are higher.
Hence my question to Mathieu ... would there have been no inversion of the data before analysis? Under Matlab or Scilab this can happen easily.
So much so that the resonance (of a bearing probably) visible around 11000hz almost disappears in the noise. Maybe there was a filtering out?
On the spectrum without pantone we can I think, to distinguish a comb of stripes can be due to a sick bearing precisely. Difficult to say without an analysis of the signal with the characteristics of the bearing (if it exists).
Does page 15 indicate a loss of compression on cylinder 3?
0 x
- camel1
- Pantone engine Researcher
- posts: 322
- Registration: 29/01/05, 00:29
- Location: Loire
- x 1
- Contact :
Hi everybody !
Well, Mathieu provided me with this first document with all the reservations concerning an analysis in progress ...
He even told me that we could perhaps wait before publishing it as it is ...
It's true Lio, that we are staying a bit on our end, and that we would like to know more, but it will come, he works on it ...
For the history of the knocking of the piston, I already had discussions with the guys from the analysis lab of the IUT, who told me that this phenomenon is present in all engines (even new!), And that it is due to the action of the linkage on the piston, which gives longitudinal forces, but also lateral. During the stroke of the piston, and because of the functional clearances, there is a position where the piston, which is actually crooked, will tip.
This phenomenon contributes largely to engine noise. This lab has worked for car manufacturers, on the latest HDI generations (or equivalent) to optimize the design of the linkages and the cylinders / pistons, in order to reduce this slamming (these mills are actually quieter, compared to old diesels. ..)
This could have been developed thanks to the vibration analysis ...
It is therefore not a rant, the choice of the installation of the sensors was made according to their past experiences and the precise idea of what they could expect to harvest.
But it is true that the modification of the vibratory signatures without / with is not obvious, I think it is mainly due to the failure of the water supply ...
What we see on these diagrams is only a first draft ... this calls for another manipulation on a perfectly functional prototype ... in a while ...
The answer (or at least part of it) is that the transverse accelerometer was placed on the block, opposite cylinder 1, and that it was in fact more receptive to noises coming from this cylinder.
We can clearly see a noise which arrives in the 180/270 ° segment, which corresponds to the moment of combustion in the cylinder 3, at the same time as the ascent of the piston 1. However, its shape strongly resembles that of combustions in the others cylinders, so?
As for the uneven distribution of the phenomenon of attenuation of the 2nd peak with pantone on the other cylinders, it is probably due to the fact that the system was not 100% operational ...
For Zac,
The first attempts at stabilization, we made them without prototypes, so it is indeed a problem linked on the one hand to the bench, which is not planned for partial load tests, and on the other hand to the regulator of the merco injection pump. We simply observed the contradiction between two regulatory systems which could not reach agreement. Boulon experienced something a little similar when going to the bench of the tractor, three guys to stabilize a speed on a given load, with long hesitations to manage to make a drinking measurement ...
The idea which consists in giving an instruction rpm AND a resistant couple at the same time, then to release the accelerator to the maximum while taking this instruction (what we do on the road) is far from being simple to implement on this type of bench ...
Finally here, this pdf is a first draft, just to give us a little grain to grind, but it will be completed, and will not remain as it is, for sure!
For the rest, I just got the photo / video report of this manipulation, made by friend Vincent.
I prepare their upload, and keep you posted as soon as it's done ...
Zac, you will be able to recover a beautiful photo of the granny, for your collection, you will not be disappointed!
Go, a +++
Michel
Well, Mathieu provided me with this first document with all the reservations concerning an analysis in progress ...
He even told me that we could perhaps wait before publishing it as it is ...
It's true Lio, that we are staying a bit on our end, and that we would like to know more, but it will come, he works on it ...
For the history of the knocking of the piston, I already had discussions with the guys from the analysis lab of the IUT, who told me that this phenomenon is present in all engines (even new!), And that it is due to the action of the linkage on the piston, which gives longitudinal forces, but also lateral. During the stroke of the piston, and because of the functional clearances, there is a position where the piston, which is actually crooked, will tip.
This phenomenon contributes largely to engine noise. This lab has worked for car manufacturers, on the latest HDI generations (or equivalent) to optimize the design of the linkages and the cylinders / pistons, in order to reduce this slamming (these mills are actually quieter, compared to old diesels. ..)
This could have been developed thanks to the vibration analysis ...
It is therefore not a rant, the choice of the installation of the sensors was made according to their past experiences and the precise idea of what they could expect to harvest.
But it is true that the modification of the vibratory signatures without / with is not obvious, I think it is mainly due to the failure of the water supply ...
What we see on these diagrams is only a first draft ... this calls for another manipulation on a perfectly functional prototype ... in a while ...
ThierrySan wrote:We see that the vibration of the engine block is greater during the explosion in chambers 1 and 3 and less significant (or even zero) in chambers 2 and 4.
The answer (or at least part of it) is that the transverse accelerometer was placed on the block, opposite cylinder 1, and that it was in fact more receptive to noises coming from this cylinder.
We can clearly see a noise which arrives in the 180/270 ° segment, which corresponds to the moment of combustion in the cylinder 3, at the same time as the ascent of the piston 1. However, its shape strongly resembles that of combustions in the others cylinders, so?
As for the uneven distribution of the phenomenon of attenuation of the 2nd peak with pantone on the other cylinders, it is probably due to the fact that the system was not 100% operational ...
For Zac,
The first attempts at stabilization, we made them without prototypes, so it is indeed a problem linked on the one hand to the bench, which is not planned for partial load tests, and on the other hand to the regulator of the merco injection pump. We simply observed the contradiction between two regulatory systems which could not reach agreement. Boulon experienced something a little similar when going to the bench of the tractor, three guys to stabilize a speed on a given load, with long hesitations to manage to make a drinking measurement ...
The idea which consists in giving an instruction rpm AND a resistant couple at the same time, then to release the accelerator to the maximum while taking this instruction (what we do on the road) is far from being simple to implement on this type of bench ...
Finally here, this pdf is a first draft, just to give us a little grain to grind, but it will be completed, and will not remain as it is, for sure!
For the rest, I just got the photo / video report of this manipulation, made by friend Vincent.
I prepare their upload, and keep you posted as soon as it's done ...
Zac, you will be able to recover a beautiful photo of the granny, for your collection, you will not be disappointed!
Go, a +++
Michel
0 x
We were on the brink, but we made a big step forward ...
laurent.delaon wrote:for the second pic page 17, maybe it is the shock of the cam heads when it comes into contact with the pusher?
there is no push on these prehistoric nags there are only rockers.
and not looking on the side of the blow of the timing belt there is not either.
@+
0 x
Said the zebra, freeman (endangered breed)
This is not because I am con I try not to do smart things.
This is not because I am con I try not to do smart things.
- camel1
- Pantone engine Researcher
- posts: 322
- Registration: 29/01/05, 00:29
- Location: Loire
- x 1
- Contact :
Hi everybody !
I added a page with the photos of this day at Carnot, it's there:
http://reaction.directe1.free.fr/Merco220D/240307.html
See you soon !
Michel
I added a page with the photos of this day at Carnot, it's there:
http://reaction.directe1.free.fr/Merco220D/240307.html
See you soon !
Michel
0 x
We were on the brink, but we made a big step forward ...
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