2014-2020 Formula One 1.6l V6 turbo engine formula

[gruntguru]

(btw - at which car dealership can we buy a stratified charge gasoline car ?)

Most GDI engines have stratified charge at part load.

[gruntguru]

Main reason is NOx emissions. 3 way cat cannot reduce NOx if lambda >1 (lean). Apart from this, jet ignition with homogeneous lean would appreciably improve economy. The other problem is power falls as mixture is leaned so the maker would have to provide a larger engine or forced induction.

I don't quite understand the other problem. What power falls - under partial load? Couldn't such an engine just swicth between different modes?

If the engine uses Jet Ignition lean mode at full load, the peak power will be reduced significantly.

[toraabe]

Does the ignition in the prechamber need a high injection pressure? AFAIK no. And pre-chambers come from the diesel world, right?
Taffin lately said: "We don’t hit the 500bar fuel pressure limit at the moment. I guess it’s going to be more if you have multiple injections and trick things like that, but so far we are not on that limit. We are already in that direction and we are getting closer and closer to a diesel engine in that respect."

When it comes to pre chamber diesel.
Merc OM 606 https://www.youtube.com/watch?v=hf5lLMCWWYc

[R_GoWin]

Pre chamber ignition is where it's at right now. HCCI doesn't seem to be for high performance applications....

This concept doesn't seem overly complicated, especially given how fast manufacturers are implementing it in their f1 engines. Why don't we have this technology already in our everyday cars? Does it require special fuel or are such engines less reliable/durable,..something else?

-Cost-benefit trade off
-unproven performance over the whole speed-load map
-parasitics of turbo system

When asked why the Indycar regulations did not go down the F1 way for 2014 to make DI mandatory and get rid of PFI - someone once said that F1-style technology, comes with F1-style price tags. 500 bar direct fuel injection is not where the mainstream market is at and IS expensive. I think the same holds for the Mahle system - fuel systems suppliers have always come up with more and more expensive options. I doubt the latest Mahle Jet Ignition system sits on the favourable side of the cost-benefit trade-off, given that you can achieve a lot with 'good-old' turbocharged GDI (and the different combustion modes).

Also before uptake by OEMs on a production engine - the system would have to prove itself to be reliable enough during its entire life cycle and all kinds of use/abuse that the end user puts the engine through. The benefits of this system over the whole speed load map is not proven yet. I do not doubt Mahle's claims of benefit during the lean mode - but I have concerns of injector tip temperatures, injector coking, HC emission during homogenous mode (more wetted area - so SFC too), soot on cold start, light load operation etc. From Ringo's link - the thermal efficiency benefits appears to come from boosting all over the speed-load map. So that brings a systems level trade-off question - will the benefits of this combustion systems offset the parasitics of a larger turbo? And the BSFC benefits are compared to a naturally aspirated SI engine - which is misleading. MAHLE has clumped the benefits of two technologies - turbocharging and Jet Ignition. So in effect they don't answer how exactly this is better than turbocharged+GDI - where most OEMs are at already.

As far as I see the biggest benefit of this system and the reason why its popular among large bore gas engines is the greater combustion speed, and the ease of integration into a current hardware. Most of those heavy duty large engine manufacturers actually operate in the diesel world. So this system gives them an easy entry point to tap into the natural gas market, with a diesel engine, without having to pour $millions into a new engine development program for natural gas. (swap diesel injector for jet ignition - among other changes - like conrod to achieve suitable CR). The powerful ignition system allows them to use a core engine hardware developed for diesel with only a few changes. You do not need to redesign the head or change the ports originally designed for swirl. The lack of tumble/turbulence intensities required for flame propagation is compensated by the high energy turbulent torch jet ignition system.

Modularity remains the buzz word in the automotive arena. If engine companies can get away with selling the same core engine hardware for diesel and natural gas - they will!

[gruntguru]

The Mahle system is designed for, and targeted at the gasoline engine market.

[R_GoWin]

The Mahle system is designed for, and targeted at the gasoline engine market.

Agree. I suppose I should have made 2 separate posts. Part of it was in reply to Jure based on the links from Ringo (the ecoboost project at Ford using Mahle's Jet ignition on gasoline engine) and the other part was in addition to NL_Fer's video links on MAN gas engine and why its popular in that market. (still learning the ways of communicating succinctly on the forum!)

[gruntguru]

HCCI and Jet-Ignition has come up in several of the engine threads here. Perhaps this thread is the most appropriate in which to focus on combustion?

Here is an update on what might be happening in the Mercedes and other engines.
http://www.motorsportmagazine.com/f1/f1s-power-secret/
The article suggests a combustion pre-chamber which is entered by a protrusion on the piston crown as it approaches TDC.

[Blackout]

Are he saying that they either use a spark plug which is placed in the main chamber or a spark plug which is placed in the pre-chamber with a piston that has a movable extension

[PlatinumZealot]

Nice technical arti... Oh! wait it's Mark Hughes.. I will read with caution.

[NL_Fer]

What would be the point of starting compression ignition in a prechamber? I though HCCI was about homogenous burn of the mixturen in the whole combustion chamber.

Thinking further why wouldn't they use Gasoline Stratified Injection Compresssion Ignition. It also has increased compression ratio, increased efficiency and prevent knocking. Look at Hyundai and Delphi's work on GDCI. It looks very usefull for f1 cars.

[Edis]

So guys, what's the opinion about the engines using HCCI? It is a rumour that keeps turning up, but imo is a total nonsense.

I believe HCCI has a slow burn rate, to slow to run at 10000rpm
HCCI is limited in power, so unusable in WOT, which is 70% of an f1 average lap
Even using it in slow corner exits, would just be usable for a few second, saving 1kg a race?

So i don't think HCCI is the technology used at the moment. It is great for a consumer car combining efficiency and low NOx emissions, but it has no use in f1.

HCCI has a very fast burn rate, especially so at high loads. Typically you have to dilute the charge with air and exhaust to avoid excessively high burn speeds, which will limit how high loads can be used.

But HCCI is very difficult to control and the fact that variable valve timing isn’t allowed in F1 doesn’t make it easier.

Jet ignition is far easier to control. You simply inject up to a few percent of the total fuel in the pre-chamber 50 crankshaft degrees or so before the spark is triggered and then the jets leaving the pre-chamber nozzles will rapidly ignite the main charge.

[godlameroso]

The MGU-H can be used in conjunction with the variable trumpets to influence induction timing if you get creative with your cam shaft durations.

[ringo]

HCCI and Jet-Ignition has come up in several of the engine threads here. Perhaps this thread is the most appropriate in which to focus on combustion?

Here is an update on what might be happening in the Mercedes and other engines.
http://www.motorsportmagazine.com/f1/f1s-power-secret/
The article suggests a combustion pre-chamber which is entered by a protrusion on the piston crown as it approaches TDC.

I don't think the engines are HCCI. They may simply be Jet Ignition combustion. the article seems to be throwing spaghetti at the walls hoping something sticks down the line.

As for low engine speed and part throttle, i think the MGU will manipulate the boost pressure through the compressor to eliminate most of the part load and low engine speed issues.

[godlameroso]

Another benefit of having a very powerful MGU-H, it's power to the turbine compressor is unlimited, so you can do some bizarre Miller cycle type things that a lot of people probably never accounted for. The variable trumpets and MGU-H along with some clever cams can provide all the benefits of an extreme Miller cycle with non of the drawbacks(namely low rpm and part throttle).

[NL_Fer]

Maybe not HCCI, but i think some form of auto-ignition can be used. Increasing efficiency, askes for an increased compression ratio and to prevent knocking injecting then fuel, just before tdc. Keep increasing Cr and some form of Auto Ignition wil start.