مصر موتورز مجتمع السيارات - SAAB should be here nearly soon due to the same soLe agent for V.W in egypt is a deaLer for Spyker Cars TOO !!

take a good Look for this very smart engine

saab svc engine concept promo 2000

http://www.youtube.com/watch?v=oxR-3Un6WkU

Prodrive Variable Compression Ratio Engine

http://www.vehicular.isy.liu.se/Lab/...es/engine2.gif

http://t0.gstatic.com/images?q=tbn:8...mg01-1.jpg&t=1

<TABLE border=0 width="100%"><TBODY><TR>< TD width="50%">Saab new engine Saab unveiled a revolutionary new engine concept, a world first, called Saab Variable Compression, or SVC. The 1.6 liter SVC engine offers the power and performance of a regular 3.0 liter V6 engine while providing fuel economy and emission levels that are better than those of a 1.6 liter engine with fixed combustion

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http://www.autointell.com/news-2000/...-2000/Saab.JPG

For example, 95 octane gasoline has the same resistance to self-ignition as a mix of 95% octane and 5% heptane.

But why do we need fuel with high resistance to self-ignition under pressure? The answer is simple, the efficiency of the engine depends of the compression ratio, thus how much the air-fuel mix will be compressed before the ignition. If in a given engine we use gasoline with lower octane rating than necessary we will cause a lot of damage. Not only the fuel-air mix will ignite early but also that ignition is sudden and uncontrollable. There will be multiple flame fronts and sudden pressure spikes instead of a controlled ignition that we normally have with spark plug.

The main parameters that dictates what kind of fuel is suitable for every engine are three, the geometric compression ratio, the electronic fuel and ignition management and the existence or not of a supercharger.

1).The geometric compression ratio is defined from the ratio of the cylinder volume with the piston at the TDC to the cylinder volume with the piston at the BDC. The geometric compression ratio is fixed for a given engine and can only be change with mechanical alterations (ex piston change).

2).The electronic fuel and ignition management is a more complicated matter.

In a piston engine theoretically the ignition should take place when the piston crown reaches the TDC. If the fuel-air mix ignites earlier the exhaust gases will provide a resistance at the -still going upwards- piston, if it ignites after the TDC pressure potential is wasted during the distance that the piston has already travel downwards.

http://robotpig.net/_images/photos/fuel/saab_di.jpg(engine with separate ignition coil per cylinder and advanced electronic ignition management - photo SAAB)

The world, 'theoritically' we used in the previous paragraph is very important. It implies that combustion occurs instantly in zero time, which may be almost the case in very low revving engines but the usual car and motorcycle engines behave differently. The optimum timing for ignition is to take place without decelerate the ascend of the piston to TDC and without waste downward piston travel (after the TDC) and energy.
The fuel-air mix needs a certain time to fully combust and the available time the piston stays around the TDC decreases the more the engine spins in higher revs. The optimum ignition time is the one that will give the maximum gas pressure when the piston is in the TDC, thus in high revs the ignition must start when the piston is still ascending to give time for the pressure to build up until it reach the TDC. The adjusting mechanism of the optimum ignition timing is called 'Timing advance' and in modern cars and bikes is electronically controlled from the electronic ignition.

If the electronic ignition is advanced and there also is a knock sensor an engine even if it is set up to use 98-octane fuel can also operate safely with slightly lower octane rating gasoline. In that case the ignition takes place earlier during the ascend of the piston. That may reduce the efficiency and the power of the engine but it also prevents fuel mix self-ignition and engine wear. Contemporary engines can tolerate lower octane fuel or take advantage of high-octane fuel to a point.
In reality even a very advanced electronic ignition can do much by itself. A normally aspirated car with indirect fuel injection has almost insignificant power benefit from higher-octane fuel that borders in the statistic error when measured in a dynamometer. A high-revving motorcycle engine with a high compression ratio may have some benefit but small nonetheless.

One can tune an engine to exploit high-octane gasoline and thus be more efficient and powerful but then the use of regular 95-octane unleaded may damage it.

Direct injection with pilot fuel injection, multi-phase injection and stratified charge have more ways to exploit a better fuel and even if they are tuned for high-octane fuel use are very flexible with normal gasoline. Dynamometer tests show a detectable and sometimes significant benefit from high-octane fuel use in those engines.

<TABLE border=0 cellSpacing=0 cellPadding=0 width=250><TBODY><TR><TD class=cellpad bgColor=#e3e3e3 height=20>TDC / BDC</TD></TR><TR><TD bgColor=#f8f8f8 height=5 background=../_images/greybox_x.gif></TD></TR><TR><TD class=cellpad bgColor=#f8f8f8 background=../_images/greybox_x.gif>http://robotpig.net/_images/photos/fuel/pistonsx.jpg

In pistons engines the piston moves straight and reciprocates inside a cylinder. When it reaches the top point of its travel and its velocity momentarily is zero, this point is called Top Dead Center (TDC). The opposite one, when the piston is down and also its velocity is momentarily zero is called Bottom Dead Center (BDC).

</TD></TR><TR><TD bgColor=#f8f8f8 height=10 vAlign=bottom background=../_images/greybox_x.gif>http://robotpig.net/_images/greybox.gif</TD></TR><TR><TD bgColor=#ffffff height=20 vAlign=bottom></TD></TR><TR><TD class=cellpad bgColor=#e3e3e3 height=20>Variable Compression Engines</TD></TR><TR><TD bgColor=#f8f8f8 height=5 background=../_images/greybox_x.gif></TD></TR><TR><TD class=cellpad bgColor=#f8f8f8 background=../_images/greybox_x.gif>http://robotpig.net/_images/photos/fuel/svc3.jpg

In the main article we mentioned three factors that dictates how much the fuel-air mix will be compressed. There is another one (and possibly more!), the variable compression engine by SAAB (SVC - SAAB Variable Compression).

http://robotpig.net/_images/photos/fuel/svc.jpg
http://robotpig.net/_images/photos/fuel/svc2.jpg

This engine has an articulated cylinder block and there is a mechanism that allows it to rotate slightly and alter the cylinder height. This height variation is electronically controlled alongside the electronic fuel management, ignition control and supercharger. The result is very low specific fuel consumption (fuel consumption in relation with the power of the engine) because the engine can adapt to every circumstances and give the optimum compression ratio. It can also use a variety of fuels. It isn't available in the market

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http://www.sae.org/automag/techbrief...images/03c.jpg

variable compression

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apparently saab already showed the engine to the public in 2000, but this is the first time i read anything about it. if they ever manage to get this into production, it sure will give some very cool engines. the prototype is a 1.6l, with variable compression, rangeing from 8:1 to 14:1, with an output of 225bhp http://forums.finalgear.com/images/s...ustom/ohmy.gif

http://www.autozine.org/technical_sc...ngine/svc2.jpg
Saab has stunned the world by showing its variable compression ratio engine in the 2000 Geneva motor show. I’ve heard such engine for some 2 years, but this is the first time Saab disclose the details to the press. In my opinion, this is perhaps the largest single breakthrough in engine technology since turbocharging and electronic engine management.

Why is variable compression ratio so fascinating? As everybody knows, fixed compression ratio is always a constraint for supercharging or turbocharging engines. To prevent excessive pressure in combustion chamber, hence pre-ignite ("knocking") and overheat to cylinder head, turbo/supercharger engines always employ a much lower compression ratio than normally aspirated engines so that the total pressure won’t exceed the limit when the boost pressure is added. The problem is, when the charger (especially is turbocharger) is not yet getting into full boost, that is, at low and mid rev, the combustion runs at lower compression ratio than normally aspirated engines. Therefore power efficiency at low speed is even lower than normally aspirated engines.

I remember when I was still 13 or 14 years old, I realized that problem and "designed" a variable compression ratio engine on paper. It involved variable length connecting rods to vary the position of piston’s top dead center, hence compression ratio. When the turbo is not in full boost, compression ratio is as high as normally aspirated engine (10:1 by then). This lower to 7:1 for full boost. Of course, that concept is completely out of imagination and is no way to be feasible. Today - a dozen years later - Saab finally realized the variable compression ratio engine.

Named SVC (Saab Variable Compression), the engine implement VC by an innovative and interesting method - slidable cylinder head and cylinder. Let’s look at the following pictures for illustration.

http://www.autozine.org/technical_sc.../svc_draw1.jpg http://www.autozine.org/technical_sc.../svc_draw2.jpg
Left: high compression ratio; Right: low compression ratio

As seen, the SVC engine have a cylinder head with integrated cylinders - which is known as monohead. The monohead is pivoted at the crankcase and its slope can be adjusted slightly (up to 4 degrees) in relation to the engine block, pistons, crankcase etc. by means of a hydraulic actuator, therefore the volume of the combustion chamber (when piston is in compressed position) can be varied. In other words, compression ratio is also variable.

SVC is cleverer than any previous patents for variable compression ratio engines is that it involves no additional moving parts at the critical combustion chamber or any reciprocating components, so it is simple, durable and free of leakage.

The monohead is self-contained, that means it has its own cooling system. Cooling passages across the head and the cylinder wall. There is a rubber sealing between the monohead and engine block.

http://www.autozine.org/technical_sc...ngine/svc1.jpg
The VC allows the Saab engine to run on very high supercharging pressure - 2.8 bar, compare with the latest 911 turbo’s 1.94 bar, or about twice the boost pressure using by 9-3 Viggen. So high that today’s turbochargers cannot provide. Therefore it employs supercharger instead. At other speed, the VC is adjustable continuously according to needs - depends on rev, load, temperature, fuel used etc., all decided by engine management system. Therefore power and fuel consumption (hence emission) can be optimized at any conditions.

The SVC engine shown in Geneva is the third generation prototype, although production is still far away. It is an inline 5-cylinder with 4-valve head. The displacement is just 1598 c.c. to take advantage of the outstanding efficiency. Compression ratio can be varied between 8:1 and 14:1. With the supercharger, it output a maximum 225 hp and 224 lbft, something similar to a Honda 3.2-litre V6. However, its fuel consumption is very low. Saab claims it saves 30% compare with equally powerful conventional engines.

In terms of specific output, it achieve 150 hp per litre, which must be a world record for production car. At the same time, it is expected to fulfill all foreseeable emission regulations, including the tightest EU4. Another advantage is the suitability to different grade of fuel, especially in America where lower Octane gas is common. The engine management system detect the fuel grade and decide the most appropriate compression ratio to be used.

Saab started developing SVC in the late 80s and acquired the first patent in 1990. The first prototype was a 2-litre unit but was considered as more powerful than needed. The second prototype was a 1.4-litre inline-6 but it had problems about packaging, so the inline-5 configuration was eventually chosen.

More work has to be done to make a SVC into production. The production unit might not be the same as this one, but it is believed that General Motors has green lighted the full development, which requires big investment from parent company.

source

if you don't wanne read: basically it's a normal engine, but the cylinder is attached to the head, and the head can be raised or lowered, giving bigger/smaller combustion chamber, giving different compression ratios

Saab 9-5 3.0 TiD engine

http://www.youtube.com/watch?v=lvoi3yKlNRY

Saab 9-5 review 2010

http://www.youtube.com/watch?v=FOqfTeid9sw

saab_900 dieseL_engine

http://www.rapidmanuals.co.uk/image/...04-500x500.jpg

WHAT A VERY STUNNING CARS REALLY??!!

http://www.youtube.com/watch?v=Wb20-AFJG0E

http://www.cartype.com/pics/3105/sma..._from_jets.jpg

http://www.saabnet.com/tsn/press/060221psm.jpg

http://upload.wikimedia.org/wikipedi...arken-Logo.jpg

http://www.orangeinks.com/wp-content..._evolution.jpg

GIFT4UGIFT4U

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