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Old 01-27-2010, 03:33 AM   #1
AVANTI R5
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Default Hyundai is wary of direct injection in small engines






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Cost and complexity are discouraging Hyundai from applying direct injection to small engines.

Direct injection reduces fuel consumption and emissions and in some applications boosts engine performance.

The automaker's new family of engines, Theta II, has 2.0- and 2.4-liter four-cylinders with direct injection. But future engines with a displacement of 1.6 liters or less may not, said John Juriga, powertrain director at the Hyundai-Kia America Technical Center Inc. in Superior Township, Mich.

For the United States, "I think you will see us over time transition very heavily" into gasoline direct-injection engines, said Juriga at a Hyundai Motor America press event at the tech center this month.

But for a 1.6-liter engine or below, direct injection may not make sense as a fuel economy measure, he said.

Juriga said direct injection is more expensive than the multipoint fuel-injection system on Hyundai's 1.6-liter engine. Cost is an issue for Hyundai's price-sensitive small vehicles, such as the Accent.

There also is the issue of complexity. For smaller engines, "it gets more difficult when you have four valves, the injector and the plug all in a very small-sized bore," Juriga said. Bore is the diameter of the holes drilled into the engine block for use as cylinders.

Juriga said "there is still more room to get more fuel efficiency" from smaller engines without direct injection.
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Old 01-27-2010, 04:53 PM   #2
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BMW and PSA did well with DI in the 1.6L engine in the Mini and Peugeot 207 though...
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Old 01-27-2010, 04:59 PM   #3
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Originally Posted by neg_matnik View Post
BMW and PSA did well with DI in the 1.6L engine in the Mini and Peugeot 207 though...
Other than the excessive carbon build up in the intake ports, I agree. This seems to be common among current DI engines though.
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Old 01-27-2010, 09:32 PM   #4
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Originally Posted by Godmal View Post
Other than the excessive carbon build up in the intake ports, I agree. This seems to be common among current DI engines though.
this is actually a bigger problem than people realize.
sometimes the carbon buildup is so much that the only way to clean the valves is to remove the head.
they need to develop something which sprays the valves occasionally to keep the carbon from building up.
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Old 01-27-2010, 09:58 PM   #5
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Originally Posted by bugeye829 View Post
this is actually a bigger problem than people realize.
sometimes the carbon buildup is so much that the only way to clean the valves is to remove the head.
they need to develop something which sprays the valves occasionally to keep the carbon from building up.
I like my DI, but I am concerned I'll pull off the intake manifold one day because the engine is throwing misfire codes and find my intake ports clogged. It will be really interesting to see how DI plays out in the long term.
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Old 01-27-2010, 10:12 PM   #6
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I think that's pretty fair once you get smaller the advantage also gets smaller. I am sure a thousand dollar price hike would push more people away than getting 36MPG instead of 34MPG. Also does any one know if the dual injection method that Toyota uses gets around the carbon build up issue?
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Old 01-28-2010, 09:24 AM   #7
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Originally Posted by quentinberg007 View Post
I like my DI, but I am concerned I'll pull off the intake manifold one day because the engine is throwing misfire codes and find my intake ports clogged. It will be really interesting to see how DI plays out in the long term.
What kind of car? I've already seen it on Minis and bmws.
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Old 01-28-2010, 09:18 AM   #8
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Originally Posted by bugeye829 View Post
this is actually a bigger problem than people realize.
sometimes the carbon buildup is so much that the only way to clean the valves is to remove the head.
they need to develop something which sprays the valves occasionally to keep the carbon from building up.
Exactly, like a tiny port injection set up to keep the valves clean and extra fuel when needed.
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Old 01-28-2010, 10:12 PM   #9
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Quote:
Originally Posted by bugeye829 View Post
this is actually a bigger problem than people realize.
sometimes the carbon buildup is so much that the only way to clean the valves is to remove the head.
they need to develop something which sprays the valves occasionally to keep the carbon from building up.
too bad the average driver wouldnt be able to properly care for a water injection system. cool the combustion chamber a bit and keep it clean.
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Old 01-27-2010, 10:40 PM   #10
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Originally Posted by Godmal View Post
Other than the excessive carbon build up in the intake ports, I agree. This seems to be common among current DI engines though.
That probably has to do with DI engines creating more particulate, similar to Diesel. I don't think I've seen much talk about this, something about creating better fuel economy but at the same time burning dirtier probably wouldn't set well with the green folks.
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Old 01-28-2010, 09:23 AM   #11
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That probably has to do with DI engines creating more particulate, similar to Diesel. I don't think I've seen much talk about this, something about creating better fuel economy but at the same time burning dirtier probably wouldn't set well with the green folks.
On the Mini S N14 engine, its because of the oil vapor separator system. Coupled with the turbo and more oil/vapor in the intake tract, it builds up as carbon around the intake valves and ports. No fuel spraying back there to keep it clean and it really builds up, though this happens more if you dont drive the car hard.
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Old 01-27-2010, 05:04 PM   #12
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Complexity/technology > Hyundai
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Old 01-27-2010, 05:31 PM   #13
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Complexity/technology > Hyundai


They have the technology. It adds to the bottom line of their cars, and on their very cheap models, that may drive people away.
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Old 01-27-2010, 09:57 PM   #14
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They have the technology....
...we can make the Tiburon faster, stronger and wheel drive *wait
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Old 01-27-2010, 08:35 PM   #15
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Complexity/technology > Hyundai
You just went full SCIC, you know that?
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Old 01-27-2010, 08:47 PM   #16
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I saw a news article recently ao that said that DI doesn't always give a significant benefit in a lot of engines. There's some engineering behind it, it's not necessarily just a "add DI and automatically gain 10hp and 2mpg" thing. Certain regular engine configurations can apparently be more efficient without it. Some were speculating this may be why Honda hasn't seriously jumped on the bandwagon yet.
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Old 01-29-2010, 05:06 PM   #17
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You just went full SCIC, you know that?
Dayam, you should never go full SCIC

EVER
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Old 01-28-2010, 09:22 AM   #18
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It makes sense. There probably wouldn't be significant gains with DI to justify raising the price of the car. Have to keep the super cheap cars very basic.

The rest of their line will be fine with DI.

Nick
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Old 01-29-2010, 01:10 AM   #19
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People want direct fuel injection until they have to pay to replace the fuel pump.
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Old 01-29-2010, 03:25 AM   #20
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Volvo has unveiled the first of a new range of down-sized gasoline engines that the automaker plans to launch in its cars from this year onwards. The new engines adopt the tried-and-tested method of combining two separate fuel saving technologies, direct fuel injection and turbocharging, in order to make an engine more efficient.
Volvo calls its technology Gasoline Turbocharged Direct Injection (GTDi) and it will debut in the Volvo S80 sedan in overseas markets and eventually filter across to the V70 and XC60 models. No word yet on any U.S. release but there’s a strong chance that the upcoming 2010 Volvo S60 due later in the year will feature a GTDi engine.
As for the unit debuting in the S80, it features a four-valve four-cylinder design and displaces 2.0-liters. Peak output stands at 203 horsepower and 221 pound-feet of torque--similar numbers to Volvo’s current 2.5-liter engines. Additionally, an overboost function squeezes an extra 15 pound-feet of torque when needed.
Volvo's new GTDi engine also utilizes variable timing for its camshafts. Both the inlet and the exhaust valves' opening times can be varied to optimize the overlap and ensure the correct fill rate in the combustion chamber irrespective of engine revs. This gives the combustion process maximum efficiency throughout the rev range and helps generate rapid acceleration at all speeds.
[Volvo]
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Old 01-29-2010, 04:35 PM   #21
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This is happening on EVERY Audi RS4 right now. My friend will chime in with some photo's of his but there is a massive movement being made right now in the RS4 community where people are dyno'n the car, removing the heads, cleaning all the ****, and re-dyno'n and gaining upwards of 30-40WHP. Its insane!!!! Something will have to change.

He's in the process of completing the supercharger for the car, but he went as far as individual port meth injection, and full oil catch can setup to see if that eliminates the issue once and for all.
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Old 01-29-2010, 04:55 PM   #22
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^^

Here is my 08 RS4 with severe carbon buildup at 23,000 miles. Never had a check engine light or code of any sort. The buildup was so gradual I didn't realize the power loss (-45 whp).

Every single RS4 on the boards that has opened up their intake manifold had carbon buildup, even as low as 5,000 miles. There have been reports of it coming right back after having carbon buildup cleaning done. This is due to direct injection and not having fuel sprayed behind the valves to clean them. VW is aware of this problem on all of their direct injection FSI motors and has released official documents of their awareness of this being a problem. They offer no solution.


With 800 miles on the odometer:


With 23,000 miles on the odometer:


















Here are the valves after the cleanup. The cleanup was done without removing the heads.











Along with the install of my supercharger, I'm installing a 8 port injection meth system and a secondary oil catch can system. Hopefully that will keep things squeeky clean!
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Old 01-30-2010, 02:50 PM   #23
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Can someone explain to me how the carbon build up gets on the intake valves?

I thought that it came from the fuel being sprayed onto the valve combined with the heat of the engine...

All of these DI engines DON'T get the fuel sprayed on the valve, so how does the carbon get there, and where does it come from??
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Old 01-30-2010, 03:25 PM   #24
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This is due to direct injection and not having fuel sprayed behind the valves to clean them.
That makes no sense. Spraying fuel on the back of valves does not clean them--sounds like an internet forum rumor. If that were true, all the old batch fired EFI systems would have spotless valves because they have every injector spray at the same time and half the required fuel is delivered twice per revolution. So the intake valves are getting sprayed a lot, more than your sequential fired motors like the modern Subarus. Carbon builds up on the back of the valves of those old engines just like any other motor, because the fuel sticks a little and gets caked on.




On the Audi motors the same thing is occurring because fuel does hit the back of the valves under many different conditions, and maybe there is something about the design that makes it build up even worse than your typical port injected motor. Spraying on the back of the valves is the problem, not the fix.



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All of these DI engines DON'T get the fuel sprayed on the valve, so how does the carbon get there, and where does it come from??
This is true only when the injector fires during late in the compression stroke (to create stratified charge). The goal is to have a sort of "column" of fuel right by the plug. This is what we normally think of when we think direct injection. But you can't use stratified charge (in the compression stroke only) during higher load and cold start. So on the Audi motors, during the compression stroke the valves are of course closed and the fuel is sprayed into the bowl of the piston:



Now the fuel injection timing logic is a lot more complicated on a direct injected motor compared to a sequential port injected motor. During higher load operation, the injector may fire twice in one cycle and at least part of the fuel charge may be sprayed during the intake stroke so that the mixture is more homogeneous. And if you look at that first pic, you'll see that it's certainly possible to accumulate carbon on the back of the valves just like on port injected motors. During cold start, the fuel sprays during the intake stroke and then again during the power stroke to warm up the cat.

I have an article from a few years ago which explains all this, although it makes no mention of carbon buildup because I don't think people had been noticing the problem yet. Just remember that late 70s port injection was pretty unreliable by today's standards. Just give it time, any 1st generation technology just needs more development.

Last edited by arghx7; 01-30-2010 at 04:52 PM. Reason: injector timing
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Old 01-30-2010, 05:14 PM   #25
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That makes no sense. Spraying fuel on the back of valves does not clean them--sounds like an internet forum rumor. If that were true, all the old batch fired EFI systems would have spotless valves because they have every injector spray at the same time and half the required fuel is delivered twice per revolution. So the intake valves are getting sprayed a lot, more than your sequential fired motors like the modern Subarus. Carbon builds up on the back of the valves of those old engines just like any other motor, because the fuel sticks a little and gets caked on.




On the Audi motors the same thing is occurring because fuel does hit the back of the valves under many different conditions, and maybe there is something about the design that makes it build up even worse than your typical port injected motor. Spraying on the back of the valves is the problem, not the fix.





This is true only when the injector fires during late in the compression stroke (to create stratified charge). The goal is to have a sort of "column" of fuel right by the plug. This is what we normally think of when we think direct injection. But you can't use stratified charge (in the compression stroke only) during higher load and cold start. So on the Audi motors, during the compression stroke the valves are of course closed and the fuel is sprayed into the bowl of the piston:



Now the fuel injection timing logic is a lot more complicated on a direct injected motor compared to a sequential port injected motor. During higher load operation, the injector may fire twice in one cycle and at least part of the fuel charge may be sprayed during the intake stroke so that the mixture is more homogeneous. And if you look at that first pic, you'll see that it's certainly possible to accumulate carbon on the back of the valves just like on port injected motors. During cold start, the fuel sprays during the intake stroke and then again during the power stroke to warm up the cat.

I have an article from a few years ago which explains all this, although it makes no mention of carbon buildup because I don't think people had been noticing the problem yet. Just remember that late 70s port injection was pretty unreliable by today's standards. Just give it time, any 1st generation technology just needs more development.
Actually, the fuel spray does clean them. Carbon buildup on the older engines is likely due to poor quality gas and the way it was driven. That was nothing compared to modern DI engines. Those pics of the RS4 engine showed excessive carbon buildup, but is nothing compared to what I've seen on Mini's N14 engine.
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