Blocking off EGR

[3000GT VR-4]

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Originally posted by labman:
Right 3000. If I built a turbine vacuum pump, once started, would it run without further power since it didn't have any reciprocating parts, just a restricted intake?

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No, not at all. Where did you get this idea?

 

[3000GT VR-4]

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Originally posted by labman:
I am not sure how the compression, expansion would balance out in the real world. The faster you compress or expand a gas, the more energy lost. Why do air compressors have cooling fins, and air motors get cold?

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Because of the heat of compression. As the air is compressed, its temperature goes up. Some of this heat is transferred by conduction to the cylinder and head on the compressor, causing their temperatures to go up. The fins prevent overheating.

 

[SHOZ]

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Originally posted by 3000GT VR-4:

What is the theory behind more rapid TBN depletion? How is the EGR gas supposed to be affecting the oil?

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Exhaust gas has a low pH.

 

[brianl703]

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Originally posted by 3000GT VR-4:
If we accept this to be true, and the EGR is there to reduce NOX, doesn't it make sense to leave the EGR functional?

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And what about 3-way catalysts (TWCs) that can reduce NOx into nitrogen and oxygen?

2NO => N2 + O2 or 2NO2 => N2 + 2O2

Is the linked article trying to say that the oxidation catalyst that follows the reduction catalyst can combine the nitrogen and oxygen and turn it back into NOx?

Who knows, it doesn't go into that much detail, nor does it go into any detail about what conditions under which this is suspected to happen (like, maybe, as a wild guess, with a whacked oxygen sensor?)

 

[MolaKule]

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What are the pro's and con's of doing such a thing aside from the emissions.

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Combustion chamber temperature gets too hot for CAT and O2 sensors and check engine light will come on. Average water coolant temp rises as well.

Greater oil thinning and oxidation due to higher CC temps.

 

[brianl703]

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Originally posted by MolaKule:
Combustion chamber temperature gets too hot

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I would suspect that pinging and subsequent ignition timing retard (if equipped with knock sensor) are also cons of disabling EGR.

 

[SyntheticShield]

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Originally posted by 3000GT VR-4:

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Originally posted by SyntheticShield:
I think it was on the Lubrizol website that I read that the EGR can lead to more rapid TBN depletion. Does that mean if I (I dont plan on doing so) did so that my oil would stay healthier for longer?

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What is the theory behind more rapid TBN depletion? How is the EGR gas supposed to be affecting the oil?

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Well I had hoped to gather some information on that in this thread from the posts. But the thread went into a debate over why or why not the egr should be disabled and then all posts over other things. Lubrizols site was not very forthcoming with information other than just to highlight that the EGR was the biggest contributor to TBN depletion in an oil. I started the thread inquiring as to the benefits to the oil of disabling the EGR versus the pollution effects of doing so and it kinda spiraled away from there.

Dont get me wrong though, I have learned a lot more than I bargin for in this thread, just not now the EGR effects the TBN of an oil and what the results would be of disabling the EGR against the increase in emmissions and whether or not one would out weigh the other. For instance, if my TBN stays higher then the oil is going to have a certain amount of longer life in a motor all other things being equal. So does that longer TBN retention and the reduction in oil changes and thus waste oil and filters out weigh the emmissions increase? Furthermore, just how is the EGR system contributing to TBN depletion and can anything be done about it short of disabling the EGR system?

 

[3000GT VR-4]

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Originally posted by Fuelrod:
Reciprocating piston engines have "pumping losses" but they are NOT related to compression or vacuum. They are caused by the energy lost accelerating and deceleration the weight of the reciprocating parts...

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In my mechanic's classes we were taught that pumping losses are caused by vacuum and pressure. On the intake stroke, when the piston is moving downward in the bore to draw in a fresh charge, a vacuum is created on the top of the piston. This vacuum is necessary to cause the air to move into the cylinder. It creates a differential pressure between the atmosphere and the inside of the cylinder. If there were no differential, the air simply would not move and there would be nothing in the cylinder. Multiply the vacuum by the surface area of the piston and you have the force required to pull the charge in. This force must be overcome by energy input from the engine itself. Same thing, but in reverse on the exhaust stroke when the piston forces the charge out of the cylinder. They are "pumping losses" because the engine is "pumping" the air into and out of the cylinder.

 

[Kestas]

Interesting... I heard pumping losses were from the pumping action behind the piston in the crankcase. That's why some engines have windows cast in the webs for the main bearing support. I guess there are a lot of different pumping losses in an engine.