milnersXcoupe
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Yes, this is the 2GR-FSE direct-injection V6 -
and as the pictures were SO cool - and the
Technology is carrying to the V8 460 -
I couldn't resist - so Enjoy !
http://tinyurl.com/ocycz
-quote-
If you look at the first picture, you can see that Toyota has avoided the usual cutaway techniques and instead takes a slice from the middle of the block. This chunk o' engine is motorized, and runs up and down while the engine is on display. It makes it difficult to see what's going on in the bottom end, but does an excellent job of showing off the top end.
Check out the vertical intake runners; this looks more like velocity stacks on a race engine than something we'd find in a luxury automobile.
Check out the cool little roller rockers that are used to transfer motion from the cam lobes to the valves. They add a bit of packaging height, but they also multiply valve lift and therefore require smaller cam lobes. There's the benefit of reduced friction as well.
We can also see the coil-on-plug (COP) assembly tucked between the two camshafts. It's extremely slender, and allows a narrow "included valve angle". This is important for two reasons: 1) Quite simply, it reduces packaging bulk; and 2) Narrower valve angles lend themselves to better intake and exhaust port geometry. The size of this coil is one of those "little details" that impacts so much of the engine's design.
The real story, though, lies just above and below the intake runner. You can see that there are actually two injectors for each cylinder - the top one is a standard port fuel injector, while the bottom one injects fuel directly into the combustion chamber. The two injection systems are used together to optimize the fueling over the engine's operational envelope.
As described in the January 2006 issue of SAE Automotive Engineering International, the system primarily relies on the port injection system when low engine speeds are combined with high loadings. Under these conditions, a direct injection scheme cannot properly atomize the fuel, and so approximately 60% of the fuel is provided by the port injector. As engine speed increases, the direct injection system takes over more of the fueling responsibility, until eventually it provides 100% of the necessary go-juice. Obviously, there some complex calculations going on to determine the optimum fueling over the engine's operating range, and that has led to over 300 patents being issued to Toyota concerning the design of this system.
There's a 7% increase in HP and 7.5% increase in torque from the system, some of which comes from the 11.8:1 compression ratio that's enabled by the use of direct injection. Better yet, the benefits apply to the entire powerband, so this is a feature that will be useful to most any driver.
The dual injection system also reduces cold-start emissions. The port injection system dumps a bit of fuel on the back of the closed intake valve; when that valve opens, the fuel is evenly distributed throughout the cylinder. As the piston approaches the top of its travel, the direct system injects a bit more fuel into the cavity on top of the piston. The total air/fuel mixture in the combustion chamber is slightly lean, but the mixture is significantly richer in the area around the spark plug, making it easier to ignite in a cold engine. The result is quicker warm-up and smoother operation when cold.
The engine produces 306 HP at 6400 RPM, and 277 lb-ft at 4800 RPM; a remarkable accomplishment for a luxury-car V6.
and as the pictures were SO cool - and the
Technology is carrying to the V8 460 -
I couldn't resist - so Enjoy !
http://tinyurl.com/ocycz
-quote-
If you look at the first picture, you can see that Toyota has avoided the usual cutaway techniques and instead takes a slice from the middle of the block. This chunk o' engine is motorized, and runs up and down while the engine is on display. It makes it difficult to see what's going on in the bottom end, but does an excellent job of showing off the top end.
Check out the vertical intake runners; this looks more like velocity stacks on a race engine than something we'd find in a luxury automobile.
Check out the cool little roller rockers that are used to transfer motion from the cam lobes to the valves. They add a bit of packaging height, but they also multiply valve lift and therefore require smaller cam lobes. There's the benefit of reduced friction as well.
We can also see the coil-on-plug (COP) assembly tucked between the two camshafts. It's extremely slender, and allows a narrow "included valve angle". This is important for two reasons: 1) Quite simply, it reduces packaging bulk; and 2) Narrower valve angles lend themselves to better intake and exhaust port geometry. The size of this coil is one of those "little details" that impacts so much of the engine's design.
The real story, though, lies just above and below the intake runner. You can see that there are actually two injectors for each cylinder - the top one is a standard port fuel injector, while the bottom one injects fuel directly into the combustion chamber. The two injection systems are used together to optimize the fueling over the engine's operational envelope.
As described in the January 2006 issue of SAE Automotive Engineering International, the system primarily relies on the port injection system when low engine speeds are combined with high loadings. Under these conditions, a direct injection scheme cannot properly atomize the fuel, and so approximately 60% of the fuel is provided by the port injector. As engine speed increases, the direct injection system takes over more of the fueling responsibility, until eventually it provides 100% of the necessary go-juice. Obviously, there some complex calculations going on to determine the optimum fueling over the engine's operating range, and that has led to over 300 patents being issued to Toyota concerning the design of this system.
There's a 7% increase in HP and 7.5% increase in torque from the system, some of which comes from the 11.8:1 compression ratio that's enabled by the use of direct injection. Better yet, the benefits apply to the entire powerband, so this is a feature that will be useful to most any driver.
The dual injection system also reduces cold-start emissions. The port injection system dumps a bit of fuel on the back of the closed intake valve; when that valve opens, the fuel is evenly distributed throughout the cylinder. As the piston approaches the top of its travel, the direct system injects a bit more fuel into the cavity on top of the piston. The total air/fuel mixture in the combustion chamber is slightly lean, but the mixture is significantly richer in the area around the spark plug, making it easier to ignite in a cold engine. The result is quicker warm-up and smoother operation when cold.
The engine produces 306 HP at 6400 RPM, and 277 lb-ft at 4800 RPM; a remarkable accomplishment for a luxury-car V6.
