What will come after the 2.4 V8?

[WhiteBlue]

I don't think high rpm is a real limitation for Direct injection.

I believe that you are in error there. The time window for injection is extremely small and stratified injection increases the requirements dramatically. They basically wrap the fuel air mixture in a cushion of unfueled air to stop the over heating at high AFRs. To still get the spray charge positioned correctly they need to control penetration very closely and keep the charge in a very small crank shaft angle.

RPM is definitely a limiting parameter which you find when you study the literature on direct injector design.

[xpensive]

In all honesty, I fail to see the purpose of treating a 4.5 V8 with a for automotive purposes massive one Bar boost, to see peak power rising with only 25% and torque, though flat as Ayers Rock, with 35? Can this one Bar boost be confirmed?

[ringo]

How do the piezo injectors work exactly?
Looking into that can give an inference of the limitations of the technology as it relates to engine speed.

18,000rpm is 4500 compression strokes per minute or 75 per second. The injectors open for a range of time on this upward stroke; the stroke lasts for 0.0133s.

Comparatively for a 12000rpm engine the stroke lasts 0.02s. Between 12,000rpm and 18,000rpm the technology is withing the same precision of hundredths of a second.

Is piezo technology at this level?

[madtown77]

A solenoid DI injector can maintian a pulse width of 0.8 ms or 0.0008 s (and relistically down to 0.5 ms). I would think for a piezo injector this is even smaller, though they haven't typically been used in production cars very often due to their size and cost.

[WhiteBlue]

I have added info on stratified injection in my last post, which I believe is relevant.

Re boost pressure of the new Porsche Cayenne turbo I have not found anything so far. It is very new.

Piezo drivers work by the expansion of crystals with varying electrical charges. The stroke is in the micrometer range and often gets amplified by a hydraulic stage like the staging of servo valves.

viewtopic.php?f=4&t=8814
A collection of sources for injectors:

[ringo]

A solenoid DI injector can maintian a pulse width of 0.8 ms or 0.0008 s (and relistically down to 0.5 ms). I would think for a piezo injector this is even smaller, though they haven't typically been used in production cars very often due to their size and cost.

Yes i just read that the piezo injectors are twice as fast as magnetically triggered injectors, or even more.

In 2006, the Bosch DI-Motronic/stratified charge combination will be modified such that a centrally located injector in the roof of the combustion chamber will spray an exceptionally fine stream of fuel into the cylinder that can be ignited immediately. Called “Spray Guided Combustion,” this GDI strategy will require advanced fuel injector designs. One version under development has magnetically operated valves with multiple aperture jets. The other uses piezoelectric actuation.

The multiple aperture injectors atomize the fuel through a disc with six to ten holes at its tip. The geometry of these openings can be altered to work with multiple cylinder designs, which should make it relatively easy to adapt this combustion technology to current engines. Plus, the combination of multiple holes and magnetic actuation makes it possible to produce compact, quick-acting injectors that are relatively low cost.

On the other end of the scale sit piezoelectric injectors. They can cycle twice as often as magnetically triggered injectors, so short duration injections can be used to generate mixture flows that are easily ignited. Plus, this injector’s circular side opening creates a cohesive cone-shaped stream flowing from the top center of the combustion chamber, and can be timed to produce a charge of varying density. Its big disadvantage is that it is larger and more expensive than magnetically operated, multiple aperture injectors.

Cost may not be such a factor for F1 as compared to production cars ^.

Convinced that a stop-start function will provide real fuel savings, but cognizant of automakers’ unwillingness to pay to integrate a separate electric drive starting system, Bosch created “Directstart” for GDI engines. It starts a combustion engine by igniting a fuel-air charge without engaging the starter motor.

http://www.autofieldguide.com/articles/080303.html
No more external starters as well. A driver can stall and restart.

[madtown77]

No more external starters as well. A driver can stall and restart.

I bet that won't be allowed.

[ringo]

Yeah, but it would make for more interesting racing. Shumacher would love it. Stall in pit entry, then start up back and off he goes.

From the numbers I think the piezo technology can live up to 18000rpm

Until now, petrol direct-injection engines have relied on wall-directed or air-wall-directed combustion processes, which redirect fuel off the cylinder wall and piston base toward the direct vicinity of the firing spark plug, where the mixture immediately ignites. This process only works if the amount of fuel and injection timing are precisely matched.

The Piezo element - made from titanium based ceramics - switches four to six times faster than conventional solenoids, allowing the fuel to be far more accurately metered. The piezo actuator is integrated into the fuel injector and directly connected to the nozzle needle. As soon as the piezo element receives electric current, the needle completely unseats at the tip, moving into the cylinder. A precise amount of fuel is delivered toward the spark plug in 0.0002 seconds.

Maybe there are other considerations, but i am yet to find them. I'm still learning about this.

[madtown77]

Maybe there are other considerations, but i am yet to find them. I'm still learning about this.

As I see it, it will be system pressure to deliver such a large burst of fuel in such a short time.

[PlatinumZealot]

I don't think high rpm is a real limitation for Direct injection.

I believe that you are in error there. The time window for injection is extremely small and stratified injection increases the requirements dramatically. They basically wrap the fuel air mixture in a cushion of unfueled air to stop the over heating at high AFRs. To still get the spray charge positioned correctly they need to control penetration very closely and keep the charge in a very small crank shaft angle.

RPM is definitely a limiting parameter which you find when you study the literature on direct injector design.

That is the thing. Can it work on an 18,000 rpm engine with:

a. One injection per cycle
b. Two injections per cycle

I have a feeling that high rpm (like 18,000rpm) is not limiting it. Suppose one injection per stroke is sufficient? Then there you have it! You can use a GDI system designed to inject say 2 times for a 9,000 rpm car. You say rpm is limiting but you need to give us what approximate rpm is the limit. 9,000? 11,000? (and even what is limiting it)

[ringo]

Maybe there are other considerations, but i am yet to find them. I'm still learning about this.

As I see it, it will be system pressure to deliver such a large burst of fuel in such a short time.

Yes the flow of the fuel. I have read of some systems injecting as much as 6 times per cycle. This may be for emissions and efficiency reasons.
For Formula 1, 6 injections may not be necessary, but 6 is showing that the fuel flow can respond to the speed of the injectors.

Hysteresis and noise is another issue, but this is more electrical than based on the engine. Hysteresis occurs with large displacement or large loads against the movement on the piezo, since stronger fields are need to drive the piezo under load.
This load is dependent on the compression ratio and boost pressure, but after reading some articles, hysteresis is only an issue with open loop operation and it does not incapacitate the injector, only affects the accuracy a bit.

[WhiteBlue]

I don't think high rpm is a real limitation for Direct injection.

I believe that you are in error there. The time window for injection is extremely small and stratified injection increases the requirements dramatically. They basically wrap the fuel air mixture in a cushion of unfueled air to stop the over heating at high AFRs. To still get the spray charge positioned correctly they need to control penetration very closely and keep the charge in a very small crank shaft angle.

RPM is definitely a limiting parameter which you find when you study the literature on direct injector design.

That is the thing. Can it work on an 18,000 rpm engine with:

a. One injection per cycle
b. Two injections per cycle

I have a feeling that high rpm (like 18,000rpm) is not limiting it. Suppose one injection per stroke is sufficient? Then there you have it! You can use a GDI system designed to inject say 2 times for a 9,000 rpm car. You say rpm is limiting but you need to give us what approximate rpm is the limit. 9,000? 11,000? (and even what is limiting it)

The German book that I quoted says that only spray guided combustion with outward opening nozzles will deliver the highest fuel savings.

It also says that all fuel injection for this method must occur between 20-10° crank shaft angle before the upper piston position in the compression phase. It says that only multiple injections allow the use of stratified charges for higher loads.

The best equipment mentioned are directly piezo operated injectors which are said to have only 30-50 micrometer of needle stroke but should theoretically have a stroke of only 7 micrometers for best performance and compact injector design.

It is also mentioned that 50-120 bar injection is typical for older combustion methods with spin nozzles and non spray guided combustion. The higher 200 bar systems are typical for outward opening piezo driven injectors and spray guided combustion.

I have figured that the 10° crank angle window for injection @ 10,000 rpm means that the time for all injection to take place is 0,00017 s. If the piezo injector can deliver 0.0002 s a multiple event is not possible and the potential for faster engine speeds is not there.

It indicates that indeed Ferrari are the leading manufacturer and that they are doing better than Porsche.

[ESPImperium]

From what i have been reading, the new engine seems to be aggreed as this:

1.6 Litre, V4, Forced Induction with unlimited KERS. Expect KERS to be up to 5 times more powerful than the 2009 spec systems for this. But there was also a rumor that all cars will be given a standardised fuel tank that is up to 10% less in fuel than the least fuel consuming race (Monza, by my records) of the season, meaning KERS relyance will be critical.

All VVTi and things like that are gonna be deemend as legal, at least untill the start of the 2015 season when the engines are frozen, with relyability rule loopholes as per current regs being closed until 2020. Basically allowing a free for all for engines for a 2 year period to get some engine manufacturers into the sport. Also expect to see more common alliances with gearboxes and such as well, as if Renault supply Red Bull, they may decide to use the Red Bull gearbox if it is still the best gearbox arround at that time.

Id expect engine performance to drop off arround 1.2 to 2 seconds a lap for the first few races of 2013, but then coming back, to arround 0.2 to 0.7 seconds a lap faster by the end of 2013.

Im going on what ive read so far with those comments.

[WhiteBlue]

Can you please tell your source. I must say I'm a bit surprised if they insist on V4. What would be the rational behind it? Surely V config is bad news for turbo charging. You need two turbos for good delivery as seen on the V8s and V6s. Initially he only 1.6L V4 engine that I found by googling quickly was a marine engine that was oriented vertically. It looked quite compact. But then I came across the Lancia Fulvia Rally car that had a 1.6L V4 and was a huge success.



Perhaps they see packaging advantages. The V4 will be stiffer and shorter than a I-4. Many methods from the V6 turbos can be carried over. It could look like this with two cylinders cut off and some KERS added.





Another reason that comes to mind is avoiding to comply with the GRE concept for marketing reasons.

[ringo]

Why restrict to 10 degrees? Or a multiple event for that matter?
Ultimate fuel savings and emissions for an F1 car is not as critical as a production car. Another thing is that piezo electronics have infinite resolution.
F1 teams may push the technology even further; that 0.0002s figure could be further reduced in time.

Resolution
Since the displacement of a piezo actuator is based on ionic shift and orientation of the PZT unit cells, the resolution depends on the electrical field applied. Resolution is theoretically unlimited. Because there are no threshold voltages, the stability of the voltage source is critical; noise even in the µV range causes position changes. When driven with a low-noise amplifier, piezo actuators can be used in tunneling and atomic force microscopes providing smooth, continuous motion with sub-atomic resolution.

We don't know how much more the technology will advance in 2 years. Injection can also be very flexible, some injection could take place on the intake stroke, then some injection on compression etc. Race fuel is also a consideration.
I agree that beyond a certain engine speed, it may not be possible to use the best techniques to obtain lowest emissions possible, but i think it is very likely that the technology can still be applied to engines revving well beyond 10000 rpm.
It may not be applied in the cleanest greenest ways, but it can be applied.

I think multi event injections work best on slow rotating engines such as diesels and long stroke applications. The concern for emissions also goes out the window with F1 engines which don't use catalytic converters.