Sequential Injection for Aprilia Motor

[Miles]

Hey,

I am team leader for Georgia Tech's team this year and we are planning on running the Aprilia motor this year. We are trying to use our Motec as the ECU for the car, except that the motor does not come with a camshaft position sensor for a sync signal for the ignition and injection timing. Has anyone come up with a sucessful way to mount a cam position sensor to the motor?

I know the stock ECU somehow uses only a crank signal and still has sequential injection/ignition, but I'm not quite sure how it works. Can someone shed some light on how this works, and if it is possible to have Motec emulate this?

Miles Henslee
GT Motorsports
Team Leader

[Miles]

Hey,

I am team leader for Georgia Tech's team this year and we are planning on running the Aprilia motor this year. We are trying to use our Motec as the ECU for the car, except that the motor does not come with a camshaft position sensor for a sync signal for the ignition and injection timing. Has anyone come up with a sucessful way to mount a cam position sensor to the motor?

I know the stock ECU somehow uses only a crank signal and still has sequential injection/ignition, but I'm not quite sure how it works. Can someone shed some light on how this works, and if it is possible to have Motec emulate this?

Miles Henslee
GT Motorsports
Team Leader

[Davidimurray]

Miles

We too are planning to run the Aprilia on a Motec - yet to get it on the dyno but hopefully in the next few weeks. We are going to try and run a wasted spark system - in affect fooling the ECU by telling it we are running a 2 stroke.

The aprilia ECU works by measuring the cranking speed for the first few revs on the starter. Where the speed rapidly changes, the ECU assumes that to be compression and electronically then sets that as a reference signal until the engine is switched off.

If you need any further info or want to discuss the setups then drop me an email at
murraydi1 at cf.ac.uk

Cheers

Dave Murray
Cardiff Racing

[rjwoods77]

Not saying you havent figured something out but when we trid to run our 90 degree v twin without a sequential system using motecs odd fire table we were told by Simon in Motec California that it wont work on. He did a simulation on his computer or whatever and it wouldnt work. I would call him and ask him about what he found out when University @ Buffalo called up trying to run a batch fire 90 degree v twin.

[Grant Mahler]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Davidimurray:
The aprilia ECU works by measuring the cranking speed for the first few revs on the starter. Where the speed rapidly changes, the ECU assumes that to be compression and electronically then sets that as a reference signal until the engine is switched off.
</div></BLOCKQUOTE>

That's pretty trick.

[Dan Deussen @ Weber Motor]

The phase recognition (meaning running sequentially) unfortunately only works on odd firing engines like V's. We use the same ECU as the Aprilia does on the our MPE750 but we have to run with a cam sensor if we want to run phased.
The trick is indeed to measure camshaft acceleration to determine which cylinder is on compression. On our parallel inline 2 cylinder engine compression occurs evenly spaced every revolution of the engine since it has an even firing event every 360 degrees. There is no chance to get the correct phasing here by only looking at the crank angle accelerations.

Phasing the system without a cam sensor can still be done this way:
1) Start the engine non-phased and then take a guess at the correct phasing. There is a 50% chance that the engine will continue to run without missing. Should the engine miss an event it can then be seen on the crank angle acceleration and the phasing can be switched 360 degrees. Of course this system has the risk that a misfire can interrupt the running and the user will not be happy with that short stutter. In order to increase the reliability of finding the correct phasing better the ECU can even try to remember the correct phasing when shutting down the engine. If the crankshaft is not rotated from shutting down the engine until the next engine start, the phasing will still be correct.

I belive the French ECU manufacturer Sagem had implemented a strategy like that into their ECU's, but had limited success with it.

[rjwoods77]

Dan,

How is that MPE610 coming along? Dead in the water or just delayed?

[Davidimurray]

Thanks for the tip Rob - I will get in touch with Simon.

Cheers

Dave

[Dan Deussen @ Weber Motor]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Rob Woods:
Dan,

How is that MPE610 coming along? Dead in the water or just delayed? </div></BLOCKQUOTE>

The way it currently looks, it's dead in the water. I am still hoping for the miracle that magically grinds a custom crank and machines custom rods. If anything changes I will of course post it.

[Drew Price]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Grant Mahler:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Davidimurray:
The aprilia ECU works by measuring the cranking speed for the first few revs on the starter. Where the speed rapidly changes, the ECU assumes that to be compression and electronically then sets that as a reference signal until the engine is switched off.
</div></BLOCKQUOTE>

That's pretty trick. </div></BLOCKQUOTE>

The Saab Trionic engine management uses the Direct Ignition cassette (coil on plug cartridge for all 4 cylinders) for, among other things, ion sensing during running, knock sensing, and to set the phase during startup.

During starting the ECU fires all 4 plugs wasted spark for the first few revolutions and measures the resistance across the spark plug gap (with resistor type plugs). The resistance across the gap is larger when there is atomized fuel in the chamber, compared to the empty chamber during the intake stroke. After the comparison is complete, the ignition runs sequential for the rest of the run event.

The ion sensing (mixture) and knock sensing work off the same principle - the resistance across the plug gap is different in a chamber that is detonating vs. rich vs. lean, and fires a sequence of pulses on the exhaust stroke of each cylinder to measure the resistance, and determine the levels of unburnt HC's left in the chamber, and adjusts accordingly.


http://i84.photobucket.com/albums/k16/Loobis71/CIMG1968.jpg



Best,
Drew

[LS1FC3]

Hey guys with the 550s,

our 2009 team is considering the SVX550 for next year. Could you tell me where you bought yours?

[Ton]

Hi Dan,

Are you using the Walbro ECUC for your MPE750 ?

We are planning on using the Aprilia with it's stock ECU (the ECUC) to get sequential firing working but Walbro won't release the information about that particular ECU.

If you have datasheets and pinouts and are willing to share, it would save us buying another ECU.

Cheers

[Dan Deussen @ Weber Motor]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ton:
Hi Dan,

Are you using the Walbro ECUC for your MPE750 ?

We are planning on using the Aprilia with it's stock ECU (the ECUC) to get sequential firing working but Walbro won't release the information about that particular ECU.

If you have datasheets and pinouts and are willing to share, it would save us buying another ECU.

Cheers </div></BLOCKQUOTE>

Hi Ton,

yes, the MPE750 is in production with the ECUC. You will probably not be able to get your hands on the calibration files needed for this ECU though. I would recommend you get the ECUA from Walbro. It is offered to FSAE teams at a very good price. Contact me through a PM if you need contact infos.

[EfiOz]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Davidimurray:
Miles

We too are planning to run the Aprilia on a Motec - yet to get it on the dyno but hopefully in the next few weeks. We are going to try and run a wasted spark system - in affect fooling the ECU by telling it we are running a 2 stroke.

The aprilia ECU works by measuring the cranking speed for the first few revs on the starter. Where the speed rapidly changes, the ECU assumes that to be compression and electronically then sets that as a reference signal until the engine is switched off.

If you need any further info or want to discuss the setups then drop me an email at
murraydi1 at cf.ac.uk

Cheers

Dave Murray
Cardiff Racing </div></BLOCKQUOTE>

This was dveloped by EFI Technology and was implemented by them for the Aprilia ECU which they developed. The ECU fires in each phase until it sees a rapid crankshaft acceleration, otherwise it switches to the other phase and so forth until it fires.

We have used it here successfully on Lsmborghini V10 engines. It does struggle when you start to use very large overlap cam timing (over 3mm lift at TDC) as it can back fire when firing on the wrong phase.

[Dan Deussen @ Weber Motor]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
This was dveloped by EFI Technology and was implemented by them for the Aprilia ECU which they developed. The ECU fires in each phase until it sees a rapid crankshaft acceleration, otherwise it switches to the other phase and so forth until it fires.
</div></BLOCKQUOTE>
The developer and manufacturer of the Aprilia ECU is Walbro Italy. EFI Technology is a competitor to them. So I do not think that this strategy was developed by EFI.

[Erich Ohlde]

What ECU's are the guys with the Aprilia's running? Just the stock Walbro? anyone using the Motec?

[Mectronik]

Hi , I'm new of this forum .

My company build Electronic control unit for both racing use and alternative fuel .

We build and ecu ( MKE1 ) for 1-2-4 cilinders engine , that have this strategy .

It's possible to configure this using 3 different metods :

1) Crank speed at TDC , in some case introducing an "artificial missfire" and checking it .
2) Looking at intake pressure sensor ( connected to only 1 cilinder )
3) Of course with CAM sensor

The ecu start in semisequential mode , and You can decide how and when search to run in sequential mode .