Friday 2010-12-10 Dev. video update and Discussion

[W32Blaster]

well not as simple as that.

The ideal mixture is about 14:1, also called lambda=1.

But if you have certain parameters of use like
RPM
accelaration,
Airtemperature high, low
Airpressure high, low
Cold motor (less evaporating fuel in cylinder and thus richer mixture needed)

etc. etc. etc.

you get lots of changes in actual needed air to fuel ratio. Many FuelInjection Systems are a not specified to recognize all those factors, where some really complicated carburators do.

So it´s not that simple one could say:
Fuel Injection is working better than a carburator in terms of providing the RIGHT mixture for all operating conditions.

[SlipBall]

Originally Posted by Richie

That's a very good question. I think because of the fuel injection of the German fighters the Allied aeroplanes will have more fun with the flames.

Damm, I think I flooded her!...

Now you know the real reason, why I fought so hard for realistic start up's .. Flames

Originally Posted by T}{OR

When burning fuel in the cylinder, if we're talking about an ideal process - you need exactly the same amount of fuel and air in your mixture. Since space in cylinder is limited, there is only so much air and fuel you can put in there (if we're not talking about turbo or supercharging). And certain amount of fuel requires exactly certain amount of air (I forgot the exact ratio but I can dig it up if you want, I have it one of my books).

The biggest downside of carburetors is that they can produce such ideal mixture only on certain RPMs, or RPM ranges. While direct fuel injection is much more flexible and can provide the engine with better mixture on all RPM ranges.

I am talking theory here, but I believe this is what Richie meant with:

erm... no, in a nutshell: mixture has different ratios, which need to be varied according to your altitude (leaner/richer mixture), besides a 50/50 mixture ratio would probably send your valves into orbit (Disclaimer: just wanted to make a joke here, please don't take it literally and start posting copy/paste engineering blabber..)
What Richie said just doesn't make sense: engines won't produce different flames if they're direct injected or carburator injected. Or maybe I got it wrong in the first place.

[Letum]

Originally Posted by Sternjaeger

erm... no, in a nutshell: mixture has different ratios, which need to be varied according to your altitude (leaner/richer mixture), besides a 50/50 mixture ratio would probably send your valves into orbit (Disclaimer: just wanted to make a joke here, please don't take it literally and start posting copy/paste engineering blabber..)
What Richie said just doesn't make sense: engines won't produce different flames if they're direct injected or carburator injected. Or maybe I got it wrong in the first place.

I have a sneaky suspicion that Thor might know what he is talking about when it comes to engines...

Originally Posted by Letum

I have a sneaky suspicion that Thor might know what he is talking about when it comes to engines...

..I bet I know a couple of things too

Originally Posted by W32Blaster

well not as simple as that.

The ideal mixture is about 14:1, also called lambda=1.

But if you have certain parameters of use like
RPM
accelaration,
Airtemperature high, low
Airpressure high, low
Cold motor (less evaporating fuel in cylinder and thus richer mixture needed)

etc. etc. etc.

you get lots of changes in actual needed air to fuel ratio. Many FuelInjection Systems are a not specified to recognize all those factors, where some really complicated carburators do.

So it´s not that simple one could say:
Fuel Injection is working better than a carburator in terms of providing the RIGHT mixture for all operating conditions.

Amen

[Spinnetti]

Originally Posted by Sternjaeger

erm... no, in a nutshell: mixture has different ratios, which need to be varied according to your altitude (leaner/richer mixture), besides a 50/50 mixture ratio would probably send your valves into orbit (Disclaimer: just wanted to make a joke here, please don't take it literally and start posting copy/paste engineering blabber..)
What Richie said just doesn't make sense: engines won't produce different flames if they're direct injected or carburator injected. Or maybe I got it wrong in the first place.

ideal mixture is still basically the same at any altitude. The difference is that the air density decreases as you go up, requiring mixture adjustments to maintain the same air/fuel ratio. Some planes had auto compensation, but most did not, so mechanical tune and operator capability also come into play here.

[MD_Marx]

Well, if this colour is the result of computation alone, I think it is remarkable!
Fantastic modelling which just blows my engineering mind away.

If we are talking realism, I would say that a carburated Merlin engine starting up from cold will emit yellow flames because the mixture will be rich. After a few minutes, i would say the flame would go blu-ish?

A Daimler Benz of the period had fuel injection so i would imagine the exhausts would be blue-ish from the start as the air-fuel mixture would have been slightly leaner? Probably 'blipping' the throttle would make the burn 'leaner' as the blower increased the air flow, so it probably went bluer?

Are there any surviving RAF groundpersonnel (engine specialist) who would know? I might drop the Battle of Britain Memorial Flight a line... but it's almost a trivial detail, isn't it?

Can't wait for the game to come out, but I'd rather wait until Oleg is happy to release it, rather than rush it.

Marx

[Azimech]

Originally Posted by W32Blaster

well not as simple as that.

The ideal mixture is about 14:1, also called lambda=1.

But if you have certain parameters of use like
RPM
accelaration,
Airtemperature high, low
Airpressure high, low
Cold motor (less evaporating fuel in cylinder and thus richer mixture needed)

etc. etc. etc.

you get lots of changes in actual needed air to fuel ratio. Many FuelInjection Systems are a not specified to recognize all those factors, where some really complicated carburators do.

So it´s not that simple one could say:
Fuel Injection is working better than a carburator in terms of providing the RIGHT mixture for all operating conditions.

I'm curious which injection systems you are talking about.

The main problem with a carburetor: it's very hard to distribute the mixture to all cylinders equally. Plus fuel injected engine are less prone to icing, they have a faster throttle response and are easier to start when cold.

[proton45]

Originally Posted by Wutz

Ha ha well even with mid forties I then hope I will never become an "adult" as you put it.
Going by some posts one could drop all input, at the most only writen signs of awe are acceptable......Thank god your type is not an admin, or forums would be a dead place.

I dont think your really getting my point...lol