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Driving without EGR valves. Is it safe for the engine?

Discussion in 'Engine Compartment' started by Deepak, Apr 24, 2015.

  1. kunwar.g

    kunwar.g Superiore

    Messages:
    522
    Gurgaon
    Grande Punto 1.3
    Question - if driving without EGR is so harmful then why is that EGR closes after the turbo spools in. If you drive over 2K rpm then anyway the EGR is closed. Like I do. Its primarily there for in city traffic where speeds are realy low and have to drive at lower rpm.
  2. Deepak

    Deepak Regolare

    Messages:
    455
    KA-30
    Bengaluru
    Punto Evo 1.3 90 HP
    exactly!
    1. At wide open throttle (WOT) emissions are not tested and so manufacturers close the valve and allow a full shot of fresh air to allow the engine to develop max power.
    2. EGRs do reduce NOx emissions, but at a high price.
    • Mixing hot exhaust gasses with the intake air reduces engine efficiency. The sole reason for using an intercooler is to lower the intake air temps. This makes the air more dense, so we get more air into the combustion chamber. The EGR works effectively to negate the function of the inter cooler.
    3.When blocking the EGR port you are redirecting the exhaust gases back out via the turbo, (where it was meant to go). The turbo now has more pressure turning the blades and the turbo will spool quicker. Most people will even be able to feel this by the “seat of their pants” dyno. ie you will feel a marginal increase in performance and that’s a good thing.

    more Info: http://www.chiptuning.com.au/egr_blanking_info/

    EGR systems ARE NOT in place to help keep the engine from getting hot. This is a myth. The reduction of combustion temps is PURELY an emissions system. This is proven from the fact that at WOT, when the engine would need to most cooling, the EGR system is CLOSED. So its perfectly OK to drive without EGR.
  3. Ganges

    Ganges Esperto

    Messages:
    3,121
    Driver Seat _/
    :
    Grande Punto 1.3
    if the reduction of temps is purely an emissions system,then why to close EGR after 2000 RPM ? is that the rpm>2000 is the reason where the combustion temp goes high ?
    Why cant more effective EGR-System be designed atleast for our lazy fiats,like add temperature controller in the Mid range of RPM(below 2000 RPM) and control/maintain % opening of EGR valve(travelling type off valve),this might reduce the turbo lag.ofcourse heatexchanger always plays a key role.
  4. Deepak

    Deepak Regolare

    Messages:
    455
    KA-30
    Bengaluru
    Punto Evo 1.3 90 HP
    why to close EGR after 2000 RPM?
    if the EGR valve doesn't close post 2k rpm, exhaust fumes are being fed into the engine at all times. This can mean poor acceleration and rough running, because the excess exhaust fumes are depriving the engine of oxygen. Because there is insufficient oxygen, there’s too much fuel, so the unburnt fuel starts spewing out of the exhaust as black smoke, especially when the engine is at idle. Fuel consumption is likely to rise substantially. Also, due to a lack of oxygen (which is needed to complete the combustion process), the engine sometimes starts to misfire.
    why cant more effective EGR designed?
    EGR valve is an anti-pollution device, aimed primarily at reducing the amount of nitrogen oxide (NOx) spewing out of the vehicle’s exhaust pipe. This is perfect according to the theory. But In the real world, EGR valves often don’t work very well.
    What goes wrong is this: the exhaust gases from the vehicle’s engine contain much more than just carbon dioxide: they also contain dozens of chemical by-products, left behind after the fuel was burnt inside the engine. One of these by-products is a fine dust, known as particulates. This dust is mostly unburnt carbon fuel. The more efficiently the diesel engine burns its fuel, the less carbon dust is produced. However, no diesel engine works with anything like complete efficiency and, over time, the carbon dust inside the exhaust gases begins to clog up the EGR system, reducing the movement of the EGR valve. This clogged EGR valve causes the engine to run badly due to an imbalance in the fuel/air mixture. Because the engine is running badly, the fuel is not being consumed efficiently. Because the fuel is not being consumed efficiently, more carbon dust is produced. Some of this carbon dust within the exhaust gets recycled by the EGR system, clogging the EGR valve still further. The more the EGR gets clogged, the more carbon dust is produced. The more carbon dust is produced, the more the EGR valve clogs. This viscious circle continues until the EGR valve jams completely open or closed.
    Ganges, drknaresh and kunwar.g like this.
  5. kunwar.g

    kunwar.g Superiore

    Messages:
    522
    Gurgaon
    Grande Punto 1.3
    Does the 75bhp have intercoller ? Thought only the 90bhp has it. Though have not looked under the hood for same :)

    The EGR closes after 2K rpm cause post that the fuel and gas get max combustion and there is less of the amount of NOx and other carbon checmicals left to be pushed out the exhaust. You will not that the black smoke comes out primarily on only at the time you increase the acceleration, once you have gained momentum there is no smoke.

    If you keep driving below 2K rpm you will have lots of carbon deposits on EGR and Manifold. Some pics can be seen in the EGR cleaning discussion on this forum. Why else is it recommended to clean at every 30K km :)

    Close the EGR and you will see immediate improvement in low-end. If dont want to close, stay over 2K rpm as much as possible.
    Deepak likes this.
  6. Deepak

    Deepak Regolare

    Messages:
    455
    KA-30
    Bengaluru
    Punto Evo 1.3 90 HP
    @kunwar.g agree with you!
    and 75 MJD does have an inter cooler too.
  7. asimpleson

    asimpleson Esperto

    Messages:
    2,998
    Heptanesia
    Linea 1.3
    The engine does benefit contrary to what you believe in extended running environments. The combustion temperature is regulated to offer needed performance and not MAX performance mainly with intent to keep formation of NOx, thats true but so is the fact that engines produce less gases harmful to the environment.

    Please read here further — http://www.aa1car.com/library/egr.htm

    //WHY EGR?
    Exhaust gas recirculation reduces the formation of NOX by allowing a small amount of exhaust gas to "leak" into the intake manifold. The amount of gas leaked into the intake manifold is only about 6 to 10% of the total, but it's enough to dilute the air/fuel mixture just enough to have a "cooling effect" on combustion temperatures. This keeps combustion temperatures below 1500 degrees C (2800 degrees F) to reduce the reaction between nitrogen and oxygen that forms NOx.//
  8. Deepak

    Deepak Regolare

    Messages:
    455
    KA-30
    Bengaluru
    Punto Evo 1.3 90 HP
    @asimpleson : there are many biased views on real need of EGR in internet.
    IMO if the EGR is used to have the "cooling effect" on combustion temperature to avoid the formation of NOX, it should be functional all the time. but the same EGR doesnt bother about pollution @ higher RPM :p
    And when EGR is functional? : at Lower RPM. at higher RPM [WOT] EGR is always closed.
    So the so called "cooling effect" is only available at lower RPM. At higher RPM EGR doesn't give a damn! Its just shut.
    why is this behaviour? : we always do pollution check at lower RPM. No one really tests the emission at 100 KMPH.

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