Long project: ELITE. ELectronical Injection Timing Enhancement.
Long project: ELITE. ELectronical Injection Timing Enhancement.
Hi, Guys!
I decided to share my project with you all, although I even did not achieve any progress except for information research and stuff.
Yet I am already gaining knowledge.. and motivation..
Well, here we go…
Our loved engines are mostly equipped with the M-type fuel pump.
There are a few other pump types as you know, with here and there some differences.
The M-pump does not incorporate a mechanism to control “start of delivery”. (This is for example the case for the VP/VP pumps. There is also a H-type line pump, where SOD can also be controlled by a special mechanism)
Because the SOD must be varied, measures have been taken: the centrifugal timing device.
The timing device advances the SOD in a pretty parabolic relationship to the engine RPM, I think...
This for sure worked with the 177 HP OM606 in 1996, but it doesn’t mean that it worked perfectly.
Then, we got some bigger elements from our Diesel Gods, which makes it even worse.
As I understood, tremendous work has been done to develop bigger pump elements that compensate for the timing, as it appears to be possible to do.
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In the usual 4-stroke engines, the valves are controlled by camshafts. Camshafts are driven by the crankshaft and lift the valves.
It can be favorable to alter the timing or the lift height of the valves.
Since almost the beginning of the internal combustion engines, loads of different valve timing and lift control systems were invented and developed.
https://en.wikipedia.org/wiki/Variable_valve_timing
One of the interesting methods is cam phasing. Cam phasing allows to alter the start (and thus end) of the valve lifting event with regard to the crankshaft position.
This happens by means of altering the angle of the connection of camshaft to the driven gear.
It can look like this:
These systems are usually controlled hydraulically.
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So, I was sitting and thinking about how cool it would be to add some controllable timing device to the M-pump..
When I stumbled upon this:
This is an electronical cam phaser. With the same functionality as the old systems, but then faster and better and modular.
So now, my plan is to fit such system to the pump of the OM605 / 606 engine.
Following needs to be done:
- Test the shaft load caused by the pump. That is not so easy. I need to measure the torque on rotating pump. For such causes, I have a torque measuring shaft.
- If I would connect the pump to the measuring shaft and connect 6 injectors to the pump, and let the pump rotate with 3500 RPM, it will not be enough…
The injectors are modified to pop open at 150 bar, but do not forget: it is 150 bar DIFFERENCE between the line and the injector opening. When the injector injects fuel into the prechamber, there is already some pressure because of the compression, and then the fuel starts to burn.
With 800 Nm out of a 3-litre, the BMEP of the engine is 33 bar, but the pressure peak is much higher. And .. we do not know how much, especially in the prechamber..
- I am going to make a small block of steel with two fuel line connections and a pressure sensor from a common-rail engine. I will cut a couple of fuel lines for an OM in halves, and make flares and swivel nuts, so I can connect it in a STD-car with the pressure sensor. Then, during a full load drive, I will be able to measure the pressure in the line.
After that, I can let some check-valves be made such that they copy the pressure behavior … and then put the pump on the test bench with these modified check-valves and measure the torque.
- With the torque measuring shaft, I can measure up to 100000 samples per second, so I will be able to see the whole load profile.
- With that load profile, I will chose a suitable cam phaser (or conclude that it is impossible, because the pump needs 300 Nm, I don’t know )
- Modifications to the phaser need to be done, so it can be connected to the engine. Connections to the pump shaft, the chain sprocket and the engine housing must be engineered.
- After that, the control comes. Baldur already confirmed the possibility of controlling the phaser with a (modified) DSL1.
- Testing, mapping .. etc…
I hope you like the idea!
If you have questions or ideas - I am open for discussion, everything is welcome
I will keep you updated.
Kind regards,
Evgeniy
ill be paying close atention to your progress. i hope it works out to not be too difficult. i breifly thought how difficult it would be to adapt a H pump to one of the OM6XX series engines for the variable timing. however using an electronic cam phaser is a much more elegant solution.
(09-19-2016, 08:53 PM)R-3350 ill be paying close atention to your progress. i hope it works out to not be too difficult. i breifly thought how difficult it would be to adapt a H pump to one of the OM6XX series engines for the variable timing. however using an electronic cam phaser is a much more elegant solution.
(09-19-2016, 08:53 PM)R-3350 ill be paying close atention to your progress. i hope it works out to not be too difficult. i breifly thought how difficult it would be to adapt a H pump to one of the OM6XX series engines for the variable timing. however using an electronic cam phaser is a much more elegant solution.
What about feedback? How you will know how much advance is being applied? Nozzle holders used on this engine never equipped needle motion sensor and because of their tight mounting hole ones that did will not fit.
the VE and VP pumps didn't have any pintle lift sensors equipped yet they have variable SOI timing. that should only be necessary for PD and CR systems. in our case the feed back is from the cam phaser. the beginning of delivery is directly tied to the position of the IP cam relative to the engine so all you would have to do is look up the stock values then add or subtract the lead or lag angle of the cam phaser.
What? There was never ever EDC system without needle lift sensor. Do your research. Also it always works in closed loop with SOI (RPM x IQ) map demand.
the first generation cummins 6BT 5.9 uses a bosch VE pump which has a SOI timing advance built into the pump. the injectors have no electronic feedback to the pump even some of the later VP44 pumps have purely mechanical injectors. the system uses a hydromech advance you don't need feedback for that just some careful tuning to get it right. SOI can be controlled as an independent variable with some experimentation. the stock engine uses a mechanical advance with a fixed advance curve dependent on rpm it doesn't need to know the SOI for the electronic governor to work. all this would do is allow for more SOI timing advance and to be able to change the advance curve in real time.
* EDIT: http://dodgeram.org/tech/dsl/ISB/Vp44.htm this details the VP44 operation it doesn't incorporate a needle lift sensor instead it varies timing based on the output of the pump shaft position sensor and crank position sensor.
"A reference pulse that marks top dead center (TDC) of cylinder No. 1 is sent from the ECM once every pump revolution. By comparing this reference pulse from the ECM to the position signal from the speed sensor (IAT), the fuel pump control module (FPCM) can reference the pump's position in relation to the engine's position. This allows the fuel pump control module (FPCM) to adjust the pump timing to compensate for minor position differences between the fuel pump shaft and the engine camshaft."
About feedback:
The system I am doing a research for and already get some help for contains a harmonic drive, which incorporates kind of 3 rotating thingies:
1. A ring that will be connected to the chain gear
2. A ring that will be connected to the pump shaft
3. A shaft which:
- Stationary rotates as fast as 1. does
- When the timing needs to be altered, it rotates slower or faster. because of that, the angular refference between 1 and 2 alters.
Thus, there will be 3 angle sensors in the device. Or let's say 2: for the parts 1. and 2. .. and the electric motor which propels 3. by definition contains a sensor
So, Starynovy, you are right: feedback is necessary and must be done, but because of lack of the needle lift sensor, the angle sensors must be used.
About needle lift sensor:
I have a VW Scirocco mTDI with a 1Z engine, that used to be eTDI of course. And the engine has a needle lift sensor on the 3rd cilinder. The SOI (start of injection) is adjusted in the VE by means of rotating the roll carrier, and rotating happens by means of applying hydraulic pressure against a plunjes, and controlling that pressure happens by modulating a solenoid.
The MSA15 ECU for the 1Z contains a map that can control the modulation depending on the load and RPM ( 3D map of course). (can't find a suitable picture, sorry)
I also know that after for example a timing belt change, one must adjust the SOI in idle RPM with VAG-COM
Because just like with the line pump, the VE-pump is mounted with slotted holes, and rotating it means altering the angle.
BUT .. guys .. I honestly do not know whether the SOI is checked in a closed loop like Starynovy says. Because it can be.. but it also could be not as long as the engine is a standard engine, which can be an assumption in the factory, as it is forbidden to alter your stuff and blablabla
My idea with the phaser would be: When everything is done, make a map that just does the same as the mechanical centrifugal timing device.
Then, put the engine on a test bench... Let it turn with certain RPM and certain throttle position .. and then adjust the timing for maximum torque...
It is closed loop because of other factors influencing it, it is always demaded vs. reality and as long as that selenoid can keep it up no DTCs are triggered. You could use pressure sensing on one of pressure lines. That will be the same signal as if there was needle lift sensor.
Here is SOI table from MSA11 for example:
Cool! Thank you
using closed loop would also be my first thought.. especially because it is possible .. and because "pump pressure modulation" is pretty sensitive to temperature and stuff.. open loop would cause bad precision..
Then I have an idea: Piezo Fuel line clamp!!
This is much cheaper than an expensive sensor, and the fuel line doesn't need to be cut.
I have 2 of these for 6mm lines and I already tested it on my mTDI . It gives a 2 Volt pulse between the " body" and the " fuel line" .. that 2V are pretty good measurable with an oscilloscope, and for sure with a DSL1 it will be measurable too
I made two pictures to explain my idea about testing and measurement:
Step one:
- make modified fuel lines and measure the line pressures in a running car with full load and high boost and high rpm.
I think 3 fuel lines are okay .. the sensors are not cheap either, but I need more than one, to be sure..
The sensors can be calibratet first, to be sure...
Step two:
- Make some kind of check valves that will induce the same pressure in the lines as the life running motor ... and then drive the pump with an electric motor and a measurement shaft.
Via the pressure sensor, the functioning of the check valves can be verified. Via the measurement shaft, the pump load will become visible.
After that, the choice of the phaser will beginn...
I am curious if those CR sensors will be fast enough to show whole pressure profile. Ad "checkvalve" just use normal injectors spraying into bucket. That piezo clamp is right what you need for normal non-lab function in vehicle. That DSL1 thing shoul be able to calculate advance by sensing on teeth on flywheel and then count time until injection commences.. time x angular velocity and you have degrees and finally not shooting blind.
i was thinking the cam phaser itself could supply the feed back necessary. the DSL1 doesn't need an injection sensor to work on the stock 60X edc pump. the electronic cam phaser you intend to use must have built in position feedback to allow the ecu to control it. you could just run the pump with the torque sensor between it and the pump and a set of calibrated injectors hooked up to provide the hydraulic loading necessary to show the full load driving torque necessary. then just select the cam phaser model that can handle the requisite load. use the position feedback from that combined with the crank position sensor gives you the SOI by referencing the two vs a static table. you would need to know the degree at which each element on the pump begins delivery to build the static table, but this is established when the pump is built. if you read through the early thread detailing when Dieselmeken first started making 7.5mm elements he talks about the phasing of SOD of each element relative to the others in degrees of pump rotation. i believe he said the factory tolerance was .5 degree.
Cool project. I was hoping for something like this reading your other thread. Subscribed.
Starynovy, good that you said that... I did some research, and often, sensors have 20ms response time, which is waaaay to slow. I now found them with " =< 2ms" .. so I am searching for even better. Remember: at 6000 RPM, one revolution takes only 10 ms ... and what is the total delivery time of the fuel then ? For sure not more than 2 ms ...
About injectors spraying into bucket. The whole problem that I tried to explain is: The injector is set to pop at a pressure difference of 150 bar. That means line pressure of 150 bar when just spraying into bucket... but it will be 400 bar when spraying into a room with 250 bar pressure ... or 600 when there is 450 bar pressure.
That is the whole problem and the reason why I want to measure the line pressures: they for sure will be higher than 150 bar... but we do not know how high.
And if it would be for example 500 bar, I think that an injector cannot be set for such a high pressure, or can it be ?
Starynovy and R-3350, I think you are both right about controlling the SOI. Measuring a piezo pulse on the fuel line will work as a needle lift sensor signal, but the exact position of the pump shaft for sure will also be usable for a control strategy too. I think, when the time will come, we will investigate which strategy is better.
I will have a closer look to the elements development, I wanted to do it anyway
SurfRodder, thank you ... and thanks again for the very valueable tip about the pump tool. Will save me some annoying fabrication
Well modern common rail diesels capable of twice torque 606 will ever withstand are made for maximum combustion pressure of 250Bar and that with MLS headgaskets.. good guess would be that 606 will run at half of that at 400PS. About injection time.. should be simmilar to common rail so at maximum power it will be around 2ms (1000-2000us), that is whole injection event with pre-injections so there it could be even shorter. Also you will need to advance pump to around 30-40°BTDC to compensate so bear that in mind when choosing that phaser.
hmm, 2ms for CR engine? At which RPM would that be? Because CR has higher pressure (at load), so actually I would expect the fuel to be delivered faster? But indeed, if you say that it is including preinjections, then there is also a small portion of time where the injector is closed.
Well, at this moment, I am investigating the Harmonic Drive. Something like this:
http://harmonicdrive.de/de/produkte/einb...uc-2a.html
This will allow full 360 degrees of phasing, BUT I would like to modify it such that it will have a safety function if the electric motor fails.
About the pressure:
Althoug I also think that 250 bar is more than enough cylinder pressure, we still do not know what exactly happens in the pre chamber. I believe, there happens magical stuff, with decomposing indecomposable, compressing in-compressible and so on .. I mean, there must be a reason that these boat engines can run almost 7k RPM
What I mean is: to have 250 bar in the cylinder, there must be a X-factor higher pressure in the pre-chamber. And that pressure in the prechamber will be the back-pressure for the injector .. and (back pressure + 150 bar pop-open pressure + pressure Y to sustain certain flow) = the pressure that the pump will have to deliver.
I by the way found out that there are piezo-sensors. Their response time is measured in micro-seconds. That could be the solution !
Well it is known fact that radial rotary pump (VP44) reaches almost 1000Bar in injection event, but that is whole other story with so much stronger hard lines compared to that spaghetti on 606 and steep DI "cam" profile. I think you will be surprised with how low pressure you will measure on this engine.
Ad that duration time... CR may have bigger pressure but take this. Both of those engines need lets say 120cc/1000 to make 200kW. If one was much slower to delivery this fuel it would have to advance maybe 50 maybe 80°BTDC to complete injection event before pressure drops after piston reaches TDC. So they must have simmilar time of injection, CR od IDI matters not. Both engine use simmilar SOI in range of 20-30°BTDC so assuming that injection takes 1.5-3ms is good guess.
Here you have CR duration table.
Starynovy, thanks for the table pretty interesting to see how people made it.
Based on our calculation, I concluded together with the technical sales engineer that a sensor with up to 1.5 kHz response would be more than enough, and I ordered a sensor:
http://www.keller-druck.com/home_e/paprod_e/21y_e.asp
It is for sure not cheap, but hey .. everything for the science of STDs
It will take 4 weeks to deliver, but meanwhile I still need to source a bunch of injector lines, let them be modified .. and make a small block for the sensor to attach.
By the way, I am most likely not going to choose a phase, but build one myself. As basis, a Harmonic Drive from http://harmonicdrive.de/en/home/ will be taken
The engineer there is very very helpfull and is going to assist me in choosing the right HD after I will complete the measurements.
If somebody is interested: Harmonic Drive is fascinating
Look very carefully.
The chain-gear-sprocket will be attached to the RING SPLINE (RS)
The pump will be attached to the FLEX SPLINE (FS)
The motor that will control the phasing will be attached to the WAVE GENERATOR (WG)
now, the most important thing comes:
When the WG rotates with the same speed as the RS, there is NO CHANGE in angular position of all the 3 components, but most interesting the RS and the FS, which means timing keeps being the same.
When there is some SPEED DIFFERENCE between WG and RS, there will be speed difference between FS and RS as well, BUT including the ratio!! And there are ratios up to 160 possible. So 160 relative turns of WG to RS will lead to one turn between FS and RS. ( one turn is already too much for us)
The gear ratio also makes the life easier for the electric motor: Torque of the electric motor is multiplied by that factor. This is why the look so tiny: they can be so tiny, probably 1 Nm electric motor is more than enough.
So, in how the car works:
During constant speed/load, the electric motor is rotating with exactly the same speed as the pump chain sprocket. The pump injects fuel at the right timing.
When motor speed and/or load changes, the electric motor will accelerate or break the WG a little bit, causing relative angle change between RS and FS, which means altering the pump timing.
Accelerating and braking will be difficult because of PI-control and stuff ... but hey, the whole life is not easy
I am sorry .. But as I see, most people here drive with mechanical pumps anyway I do not think that many will switch to DSL1 because of this invention..
Yet I would be glad of course, as more people will be interested in making maps for different setups
A friend helped me with a tip:
Instead of cutting the lines, just make a sensor-adapter which will go immideately on the injector, and then bend the injector line a little bit.
Will take a lot of teflon sealant at that injector.
I actually was thinking about having a flat face inside and let it seal with a copper ring. If the sensor points in a stupid direction, just take a thinner or thicker ring and retry..
At this moment I think that is the cheapest way ...
Well, I think it will not fit.. because you are totally right, on the test bench it would fit... but I also have to do measurements in a (fast) car, and there I will have the big inlet manifold... Therefore the choice to do it on the injector.
I bought an OM606 yesterday now I can measure everything and plan accordingly. The test car has OM605 though, but that shouldn't matter.
2 words: Fucking...awesome!
Thank you guys for the appreciation
Being able to make some measurements, I modeled the necessary part of the cylinder head...
And now ... more stuff!
Now, the crucial part comes:
If the injector thread is M12x1.5 (can someone confirm it? Still need to measure or test it...) , then the thread on the sensor adapter will be M14x1.
The brass-colored part will be a sleeve with M12x1.5 and M14x1 inner thread.
The different pitch will allow me to always be able to let the sensor point in the right direction.
I made a small step again...
To be able to connect the fuel-line to the adapter, the adapter needs to have that conical hole, and that is a PITA: how to make a drawing of it, so the lathe-guy can make it?
then, I stumbled upon this:
Soooooo .. the idea is:
And then:
This of course have to be welded!!!
Because, very simple: outer diameter of the lathed-down peace would be 9mm, inner hole diameter is 5mm.
This makes an area of ( pi * (4.5^2 - 2.5^2 ) ) = 44mm^2
If there will be pressure peaks of, lets say, 600 bar ... there will be a force of
F = p * A = 60 N/mm^2 * 44 mm^2 = 2640 N ... ( comparable to force applied by 264 kg of mass)
This means that if you make a press-fit with less than 300 kg, the adapter may loosen during the test. A nice weld bead will prevent that
There is some good info here:
http://www.peachparts.com/shopforum/gene...ester.html
The one from a VW injection pump (fits M-B hard line / pipe to injector) has #6 ORB (O-Ring Boss) type of connector. Not sure if that helps at all, but it might be useful.
That is a good one, thanks! I indeed have some TDI-VE pressure lines here, and the " small side" fits. The delivery valves have M12x1.5, and the injectors have probably M14x 1.5. That is nice, I can build a similar device to pressure-test the sensor adapter assembly!
Unfortunately, things take their time. But I am not giving up!
Now I need to take care for the electronics for datalogging... and then, go for a ride!
The pressure Transmitter goes up to 2 kHz response. This is the reason why I ditched the idea of taking the CR-pressure sensor, that one would be way too slow.
It was reasonably affordable for 210 euro. If it fails, I will need a better one, which will cost me a rib out of the body
(12-08-2016, 08:30 AM)Tobulus How does it measure the pressure? If its internal Volume increases with rising pressure, you will inject less fuel on that cylinder.
(12-08-2016, 08:30 AM)Tobulus How does it measure the pressure? If its internal Volume increases with rising pressure, you will inject less fuel on that cylinder.
(12-08-2016, 03:43 AM)Evgeniy1987 The pressure Transmitter goes up to 2 kHz response. This is the reason why I ditched the idea of taking the CR-pressure sensor, that one would be way too slow.
It was reasonably affordable for 210 euro. If it fails, I will need a better one, which will cost me a rib out of the body
(12-08-2016, 03:43 AM)Evgeniy1987 The pressure Transmitter goes up to 2 kHz response. This is the reason why I ditched the idea of taking the CR-pressure sensor, that one would be way too slow.
It was reasonably affordable for 210 euro. If it fails, I will need a better one, which will cost me a rib out of the body
Guys ... it happened!
I measured the pressures!
During full throttle pedal to the metal full boost drive, the sensor measured 470 - 480 bar peak.
Around 2 bar boost, around 140cc pump.
This was a crucial measurement, a milestone in this project!
Nice! Keep it up brother!
The next step is: find a way to make 500 - 550 bar spikes in the lines in normal room circumstances.
To start with, I need to make the necessary adaptation to be able to put my pump on the test bench...
(12-08-2016, 08:30 AM)Tobulus Wrote:
How does it measure the pressure? If its internal Volume increases with rising pressure, you will inject less fuel on that cylinder.
That statement is falls: once hp line is bled of air its volume bigger or smaller won't have any affect on quantity of injection. Internal volume of the line will be constant.
(02-15-2017, 10:05 PM)Anjay1 (12-08-2016, 08:30 AM)Tobulus Wrote:
How does it measure the pressure? If its internal Volume increases with rising pressure, you will inject less fuel on that cylinder.
That statement is falls: once hp line is bled of air its volume bigger or smaller won't have any affect on quantity of injection. Internal volume of the line will be constant.
(02-15-2017, 10:05 PM)Anjay1 (12-08-2016, 08:30 AM)Tobulus Wrote:
How does it measure the pressure? If its internal Volume increases with rising pressure, you will inject less fuel on that cylinder.
That statement is falls: once hp line is bled of air its volume bigger or smaller won't have any affect on quantity of injection. Internal volume of the line will be constant.
How is things going here?
I am sorry, guys...
I couldn't finish my school yet, my loved daily car broke.. I am fighting against a pretty strong depression, while still having to do all the obligatory things.
I promise to not cancel this project.. it is just in a freezer for now.
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Hang in there-you're not alone. My mercedes is still in pieces after 3 years.
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?