EFI University

[MrDomino]

I'm curious as to what your approach was when searching for more power. With gasoline engines you adjust fuel based off of AFR and spark timing based on engine torque so it's relatively straightforward. However, with Diesels you can only advance and increase fueling but there's no real way of determining how much is too much without some sort of cylinder pressure measurement.

Also, does anyone know how Audi and Peugeot's engines were designed such that they were suitable for racing? I imagine part of it is gearing but with truck engines you really only have power for a 1000-2000 RPM or so before you need to shift. Do they just use really long gearing or what?
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I am a Mechanical Engineer.

[Techsalvager]

iirc they rev out to 5k and have 6 speeds

[CMW]

Race Engine Technology and Racecar Engineering magazines have both done in depth articles on the diesel Le Mans engines from Peugeot and Audi. Without the blatant crutches the series gives the diesel engined cars (weight breaks, fuel capacities, particulate filters, blah blah), they'd be at the back. Not to say they aren't technically advanced, just that the playing field has quite a gradient.... One of those two mags is doing a cheap back issue offer, but I can't remember which.
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Best regards,
CMW

[MrDomino]

I figured that they'd need some help from the governing bodies to get to where they're at.

Which of those two magazines do you think is better? I was looking at subscribing to Race Engine Technology and getting the backissue deal where you get the entire previous year for pretty cheap. Total cost is about $220. Is it a worthwhile investment?
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I am a Mechanical Engineer.

[TurboCamaro]

The Diesel Tuning 101 Video available on the video page of this site is a very good primer much like EFI101 for understanding the Diesel Engine.

[MrDomino]

I'm pretty confident that I'm not going to learn a whole lot with an introductory course in Diesel engines.

My questions pertain more to how do you guys tune performance Diesels when you don't have access to all of the cool cylinder pressure transducers and turbo speed sensors, etc. that I do (I work for an OEM supplier so they have all kinds of expensive equipment).
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I am a Mechanical Engineer.

[CMW]

If funds permit, subscribe to both. I will try and send you a PM you may find useful.
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Best regards,
CMW

[StantonWarrior]

[rvengineering]

We are already past the point of figuring out injection events, that’s basic and limiting to fuel. On commonrail you can increase fuel pressure in some cases and extend injection duration and change timing and depending on the engine get 30% or more power and some far less due do injector design and lack of fuel pump capacity.
Our focus lays complete on injector development and findings way to avoid pressure drop in the injector during an injection event. Due to pressure drop in the injector the quality of the combustion suffers and you get smoke and poor engine performance.

The last PDE injector we build has 47% more fuel flow and a better start of combustion decreasing engine noise in the process.
The next project will be a commonrail injector with a shaft of 22.1mm that set to handle 250Hp per injector. To bad it’s only 21Cm long and it has a top feed so it will not fit in most small car engines.

The most common problem we face with small diesel engines are the gearboxes. A diesel can build massive torque @ low RPM what we have to reduce to prevent damage and hi up the RPM range we do not have the time to inject the fuel in the desired crank angle so we need massive big injectors to get the fuel amount in and maintain a good quality of injection.

We already past the Hp levels per cc on the Le Mans cars on the engines that run PDE injectors and if we get the budged for development we can even get more Hp out of these engines as we are now running close to the max of EGT indicating that we get to the max on end of injection.

Also lambda plays in important role in the process. It’s hard to say what amount of oxygen left before you can come to conclusions as combustion is a lot different to petrol engines.
Even do we have no valve overlap and run under full load we get spots of oxygen (hi 20AFR) on some engines indicating the combustion takes place in only a part of the cylinder/piston dome. Trying to use this left oxygen is a challenge.

We also look at a thing we cal after burn. This is where a part of the combustion takes place after the exhaust valve increasing EGT and giving more exhaust gas volume as a result in some cases over speeding the turbochargers.
The main rezone we have after burn is due to a fact that we have a slow combustion as a result of poor quality of fuel injection. If you get a pressure drop over the injector you will get a bigger droplet size that will take longer to evaporate. The funny thing is this will not always result in to smoke.

Boost pressure. We intend to find a balance between exhaust pressure and engine efficiency under full load. I n most cases we have all the oxygen needed running normal boost pressure however if we fit bigger injectors than can inject more fuel in the same crank angle you will get a temperature drop in the combustion chamber due to fuel evaporation slowing the rate of burned fuel down resulting into after burn. Increasing the boost pressure will eliminate this problem a lot.
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RV Engineering.
Doktervermetstraat 14
4681 CD Nieuw-Vossemeer.
TEL: +31(0)6 13 90 61 94
E-mail adaptronic@gmail.com
www.adaptronic.nl

[MrDomino]

Why are you still using PDE injectors? It seems like using a piezoelectric common-rail system would be much easier along with allowing more precise control of injection events. I guess you'd be somewhat limited to off the shelf models from Bosch but you'd eliminate the issues you're having with injection duration at high engine speeds (not enough time to inject all of the fuel) along with better control of the pressure drop over the injector. I know you said you're developing a common rail injector for larger engines but why not try one for smaller engines?
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I am a Mechanical Engineer.

[great white]

While it sounds like you guys are more geared towards smaller diesels, I use pulse width, timing, EGT and visible smoke point for the 6+ liter turbo diesels I typically do.

Rail pressure also comes in to play if I'm building a calibration for common rail.

EGT and visible smoke point are my most useful indicators. I like my calibrations to run clean, ie: minimal smoke if any at all.

I'm still what I would call a "beginner" and I only do "street" calibrations though....I don't typically get into increasing power levels to the point of bigger injectors, dual pumps, large boost changes, etc....

I stick around 50-100hp increase range for most of my local guys and myself.

[StantonWarrior]

Opacity is always going to be one of the major limiting factors.

The projects I get involved with tend to be 2000cc 4cyl, 4000-45000 V's, and big 15L HD on/off highway. The latter currently revolves around after-treatment, currently working on SCR development due for release next year. Very interesting stuff.

[rvengineering]

@ MrDomino I’m slowly moving to smaller engines now as we are working on a Mercedes OM613 project with good funding so change is that we going to put this engine to the limed after some time and some say the OM613 it’s one of the strongest small diesel build.

@ great white to me 6+ liter is still a small engine. LOL.

This is modern diesel tuning on a old engine. 92 series V12 GM 2 stroke diesel commonrail conversion with a 900L/hour HD pump and injectors that do 1cc+ per injection.



@ StantonWarrior. after-treatment. Partical filters and adbue?????
_________________
RV Engineering.
Doktervermetstraat 14
4681 CD Nieuw-Vossemeer.
TEL: +31(0)6 13 90 61 94
E-mail adaptronic@gmail.com
www.adaptronic.nl

[StantonWarrior]

Yes, DPF and urea dosing. It's pretty impressive technology...the new systems have a vast amount of control and interaction with the engine control/calibration.

[MrDomino]

[StantonWarrior]

With regards ECU hardware, it's been heading that way for a while; TP efforts from Bosch et all are getting harder for the chiptuning tool manufacturers to work around. Boot Mode is the only way on the new stuff currently, OBD still isn't possible on most.

As for the integration of the likes of after-treatment, the project I'm currently involved with for globally the largest HD diesel engine manufacturer/supplier runs two NOx sensors, ammonia sensors, temp sensors, pressure sensors, urea quality sensors and level sensor; so without alot of emulation trickery can't be bypassed. Not that it's particularly needed, the new stuff makes more torque and offers better fuel economy BECAUSE of the after-treatment!!