Ferrari Power Unit Hardware & Software

[Vortex Motio]

Except that only one injector is allowed, and it is a direct injection system.

And yet Ferrari is using some form of this system and it is legal.

Our opinions as to whether or not a separate injector is allowed in the ignition chamber aren't relevant. The FIA decides this question, and they already have. But which way did they decide?

The full text of tech reg 5.10.2 leaves a possibility for either interpretation:

There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves. Only approved parts may be used and the list of parts approved by the FIA, and the approval procedure, may be found in the Appendix to the Technical Regulations.

Ferrari may have successfully argued there is only one injector for the cylinder, and it's in the cylinder. The other injector isn't upstream nor downstream of the valves, nor is it for charging the cylinder with fuel, nor is it in the cylinder.

AFAIK, the "Appendix to the Technical Regulations" isn't available from the FIA web-site.

What's more intriguing obviously is if Mr. Whiting didn't agree with that argument and the separate injector isn't legal. Mahle's "weeks of work" in 2015 to meet F1's requirements for Ferrari would've been fairly creative.

There is a hint that Mahle may have already been thinking of a creative solution on page 13 of their 2014 presentation, http://energy.gov/sites/prod/files/2014 ... 2014_o.pdf, where they mentioned that they've made progress on:

Non-auxiliary fueled model under development

Mahle's Ferrari article inside their recently released 2015 annual report described their system as follows:

The newly developed MAHLE Jet Ignition lean burn combustion process relies on a special surface ignition, which in turn allows for higher engine performance. The ingenious trick here is that the air-fuel mixture is preignited in a prechamber around the spark plug. This results in the formation of plasma jets that reach the piston primarily at the outer edge and ignite the remainder of the mixture.

If F1 doesn't allow for a separate injector inside the ignition chamber, then studying existing public documentation on their proposed road car systems (patents were from 2010/2011, and DOE presentation was 2014) may differ significantly than what they actually implemented for F1 in 2015. If that is true, I'll suggest that how they described their system in the annual report could be significant in a subtle way.

[FW17]

Is there a necessity for the fuel air mixture in the chamber to be rich? Jets of lean flame from the prechamber can also do the job of lighting the lean fuel in the cylinder combustion chamber.

[3jawchuck]

The full text of tech reg 5.10.2 leaves a possibility for either interpretation:

There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves. Only approved parts may be used and the list of parts approved by the FIA, and the approval procedure, may be found in the Appendix to the Technical Regulations.

Ferrari may have successfully argued there is only one injector for the cylinder, and it's in the cylinder. The other injector isn't upstream nor downstream of the valves, nor is it for charging the cylinder with fuel, nor is it in the cylinder.

Couldn't regulation 5.11.1 "Ignition is only permitted by means of a single ignition coil and single spark plug per cylinder...." put paid to them persuading the FIA that the prechamber is not actually the cylinder?

[mistareno]

I think if you are going to argue that a pre-chamber injector isn't in the cylinder, you can't then say the spark plug is. I think the FIA would say you can't have your cake and eat it too...

I hypothesized something like the image below in a similar thread elsewhere.

A single injector with indiviual calibrated nozzles. 1 nozzle injecting ~3% fuel for the Pre-Chamber and the other injecting ~97% for the Combustion Chamber. The other option would be to incorporate 2 individually controlled injector actuators within a single housing. 1 aimed into the Pre-Chamber and the other for the CC.

[NL_Fer]

I don't think the ratio has to be 3/97. Since a large portion of the fuel can be injected during intake.

[mistareno]

I don't think the ratio has to be 3/97. Since a large portion of the fuel can be injected during intake.

Mahle quote between 3 -5% of total fuel (per combustion event) is injected in the pre-chamber.

[gruntguru]

the header at the top of this page says 'TJI pushes engine combustion efficiency'
imo, essentially it does not, the combustion efficiency would already be very high at the mixture strengths normally used

the header should say 'TJI pushes high power efficiency through increased leaning'
increased leaning via increased boost and air massflow lowers cycle temperature, so reduces heat loss to coolant and exhaust
(judging by temperature-lowering benefits that are a prime feature of various novel cycles also mentioned in the F1 context)
and allows higher CR

The levels of leaning obtainable with TJI are significantly greater. There is an additional efficiency benefit from TJI which is the rapid combustion and pressure rise near TDC.

[gruntguru]

Is there a necessity for the fuel air mixture in the chamber to be rich? Jets of lean flame from the prechamber can also do the job of lighting the lean fuel in the cylinder combustion chamber.

An ultra-lean mix in the pre-chamber would still have all the problems ie - difficult to ignite, slow flame progression etc.

[wuzak]

I think if you are going to argue that a pre-chamber injector isn't in the cylinder, you can't then say the spark plug is. I think the FIA would say you can't have your cake and eat it too...

I hypothesized something like the image below in a similar thread elsewhere.

A single injector with indiviual calibrated nozzles. 1 nozzle injecting ~3% fuel for the Pre-Chamber and the other injecting ~97% for the Combustion Chamber. The other option would be to incorporate 2 individually controlled injector actuators within a single housing. 1 aimed into the Pre-Chamber and the other for the CC.

http://www.cargovic.com.au/wp-content/u ... /04/DI.jpg

Where does the air for the pre-chamber enter?

[mistareno]

Where does the air for the pre-chamber enter?

The same place it normally does.

Through the holes in the bottom of the chamber that are open to the cylinder.

Fuel is injected into the Pre-Chamber and the air/fuel mixture is simultaneously ignited by the spark plug. The explosion expands out of the small holes in the base of the chamber in 'jets' that penetrate far into the main combustion chamber. The jets can ignite a far leaner mixture in a far more even manner than would normally be achievable, significantly improving efficiency.

[NL_Fer]

I don't think the ratio has to be 3/97. Since a large portion of the fuel can be injected during intake.

Mahle quote between 3 -5% of total fuel (per combustion event) is injected in the pre-chamber.

Yes but Mahle talks about the commercial version, which uses a separate port fuel injector. This not allowed in F1. So they need to simulate the port fuel injector by injecting during intake stroke and create a homogenious mixture.

Then right before ignition, they need to inject some more fuel, to fill the pre-chamber and because of the single injector also they cannot prevent fueling the main chamber also. This will make a less homogenious mixture, but that's not a problem for F1.

So yes, total mixture will be 97/3% but the ratio for the injector itself could be different.

[mistareno]

Yes but Mahle talks about the commercial version, which uses a separate port fuel injector. This not allowed in F1. So they need to simulate the port fuel injector by injecting during intake stroke and create a homogenious mixture.

Then right before ignition, they need to inject some more fuel, to fill the pre-chamber and because of the single injector also they cannot prevent fueling the main chamber also. This will make a less homogenious mixture, but that's not a problem for F1.

So yes, total mixture will be 97/3% but the ratio for the injector itself could be different.

When Mahle previewed the system, they stated it could be used with both a PFI or DI system (for the main fuelling).

Unless Mahle threw out all their previous research work in the development of the System for Ferrari (which would be pointless for Ferrari and Mahle) I imagine they adapted what they had already designed to fit the rules, or had already developed the system so it fitted with the rule (Single Direct Injector)

Back in 2014, when Mahle first previewed TJI (Jet Injection in Mahle terminology) they stated they were already developing the system so that it removed the need for 'auxiliary fuelling' . Doing so would make the system more desirable and far easier to implement for customers (car makers).

The easiest way for them to do that would be to utilise a Dual output injector that supplies fuel to both the PC and the CC.

If an injector services a single cylinder from within the combustion chamber, has a single fuel input, electrical connection and is contained within a single housing, it would be pretty hard to argue that it wasn't a single injector regardless of how many internal solenoids/actuators/nozzles it contained.

I think the comercial system is almost exactly what they are using, with a proprietary 'Direct Injector' sevicing both requirements independently via different nozzles and actuators.

I imagine the system in the Ferrari is that development.

[NL_Fer]

It still does not have to mean the injector itself has a 97/3 ratio.

[mistareno]

Ok. I have found a recent patent by BMW that has a single injector doing exactly what I propose in exactly the same application.

This is how they have got around the 'Single Direct Injector' issue.

http://google.com/patents/DE102012202080A1?cl=en

It actually references the Mahle TJI system.

This is an image of the injector and it's interaction with the pre-chamber -

[tuj]

I speculated on the Merc thread that Merc was already doing this via PWM of the injector signal (eg. short pulse only hits the pre-chamber nozzle, while long pulse engages the main cylinder nozzles).