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Engine EGR technical ??

Discussion in 'Powertrain' started by CorollaULEV, Nov 14, 2004.

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    CorollaULEV Guest

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    EGR technical ??

    I know that on the 1ZZ-FE there is no EGR valve. Do 1998-2000 non-VVTi engines have an EGR valve? I'm under the impression that the EGR is accomplished by the VVT-i and that's why no valve is needed - am I correct?

    Do our engines have an exhaust gas temperature sensor?? If so, where is it?

    Late,
    Trav
    CorollaULEV, Nov 14, 2004
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    vortex Well-Known Member

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    No 1998+ motor has EGR that I am aware of. 1998-1999 are the only non-vvti motors as well. Neither of those have EGR.
    BTW, those are 1ZZ-FE as well... hehe

    As for the EGT - none of them do that I know of.
    vortex, Nov 15, 2004
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    RedAE102 New Member

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    I'll add to Vortex's reply... it's true, no '98+ have EGR, and none of them have an EGT sensor... Even the earlier models with EGR just had a gas temperature sensor in the EGR valve itself, not in the manifold... the exhaust gasses cool significantly before they get to the EGR valve itself...
    RedAE102, Nov 15, 2004
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    CorollaULEV Guest

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    OK - well, how does the 1ZZ-FE accomplish recirculation of exhaust gas? How is it controlled? Engines with the EGR valve/modulator setup open the valve and close it based on manifold vacuum and exhaust backpresure - higher load(low vacuum) = higher EGR flow, lower load(high vacuum) = lower EGR flow and NO EGR flow in open loop (warm up or WOT). How does the 1ZZ accomplish this without a valve to control it? If the 1998-99 1ZZ-FE motors did not have an EGR valve, then apparently it has nothing to do with VVT-i. Right??

    What up with this??

    Late,
    Trav
    CorollaULEV, Nov 15, 2004
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    vortex Well-Known Member

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    No exhaust gas is recirculated... you simply have head->manifold->exhaust system its straight out of the system.

    and you're correct - EGR has nothing to do with VVTi
    vortex, Nov 16, 2004
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    CorollaULEV Guest

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    But EGR cools down combustion temps and allows the engine to run leaner at low loads (highway, cruising) and save fuel. So the 1ZZ-FE has no EGR at all - does not recirculate exhaust gas??

    Strange - I would figure it was a necessary sort of thing to achieve that golden ULEV status and have such good highway gas mileage (40-43mpg for me on HWY). Guess I was wrong.

    Late,
    Trav
    CorollaULEV, Nov 16, 2004
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    vortex Well-Known Member

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    hehe they found they can still get low emissions and good gas mileage w/o throwing something else in there to break the system... :)

    Actually its sort of funny how really down to basics the 1ZZ is (non-vvti at least) you have various sensors here and there that just monitor things that are going on but don't try to interfere with whats going on with the engine - exception of course the ignition and fuel are always adjusted. It's kinda nice - one of the reasons I really got into this motor was its simplicity, makes it easier to mod. :) Still my only complaint with import cars is the amount of wires one has to deal with, lol...

    Of course, give me my 69 Camaro anyday... LOL -- all you need to crank the thing is 5-6 wires. And in total there must be maybe 20 wires on the whole damn car... LOL
    vortex, Nov 17, 2004
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    CorollaULEV Guest

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    Well SNAP - thanks dude! I learned something new about my car.

    As a side note - I was looking around on www.fueleconomy.org and noticed that the Celica/MR2 variety of the 1ZZ only have an LEV emissions rating. And the 2ZZ-GE gets an abissmal TLEV rating. Guess Toyota really needed the Corolla/Matrix, Prius, and Echo to green their emissions score up.

    Trav
    CorollaULEV, Nov 17, 2004
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    vortex Well-Known Member

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    hehe

    what's so funny is my emissions on my corolla were way higher before i turbo'd then after... I was all ' uhh i boosted my car and it runs cleaner? wtf!? ' probably a lot of it was the tuning of the system to run with it but all good...
    vortex, Nov 17, 2004
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    vortex Well-Known Member

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    Took the words outta my mouth... gotta be the namesake... haha Travis' always seem to think alike. <br />
    <br />
    What dominator said makes sense for a VVTi, but I would *LOVE* to know how this works in the 98/99 non-vvti versions... <img src="http://vvti.net/forums/images/smilies/smile.gif" border="0" alt="" title="Smile" />
    vortex, Nov 20, 2004
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    dominator 04 Rolla 5spd.

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    Exhaust-gas recirculation is achieved by internal recirculation via appropriate valve overlap...
    The VVT-i system can change the intake cam timing over a 60 degree range, changing valve overlap from absolutely zero (for smooth idle, easy starting and better cold start performance), to severely overlapped for a natural EGR effect at medium load (eliminating the need for an Exhaust Gas Recirculation valve), to whatever is ideal for maximum power at any point on the powerband.
    dominator, Nov 20, 2004
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    CorollaULEV Guest

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    I believe you wholeheartedly b/c this is what I've heard from several sources. However, riddle me this:

    The 1998 and 99 models do not have an EGR valve, either. They also do not have VVT-i. So, how does the non-VVT-i engine accomplish EGR?

    Late,
    Trav
    CorollaULEV, Nov 20, 2004
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    CorollaULEV Guest

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    HA - too friggin funny.

    Are we on the same length or what?

    Your name isn't Travis is it, vortex??

    Trav
    CorollaULEV, Nov 20, 2004
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    vortex Well-Known Member

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    Yeah it is... lol
    vortex, Nov 21, 2004
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    vortex Well-Known Member

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    dayum... like readin a manual n sheet... <br />
    <br />
    thanks for the info - ya learn something new every day... <img src="http://vvti.net/forums/images/smilies/smile.gif" border="0" alt="" title="Smile" />
    vortex, Nov 21, 2004
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    dominator 04 Rolla 5spd.

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    The non-VVTi versions were only LEV rated. Valve overlap was used before our variable valve timing technology. The 1ZZ-FE VVTi's exhaust valves always close at 2º ATDC; intake valves open between 5º and 48º BTDC, so there is always valve overlap, ranging from 7º to 50º.
    Chrysler's late model Neon 2.0 SOHC engines have actually dropped the EGR valve system without opting for variable valve timing.
    dominator, Nov 21, 2004
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    CorollaULEV Guest

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    Thanks dominator for entertaining our endless interrogation on the finer points of EGR ;)

    I've been school'd.

    Late,
    Trav
    CorollaULEV, Nov 21, 2004
    #17

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