Why can't they???

Discussion in 'Trucks [ Eighteen Wheelers ]' started by DevilDog911, Mar 12, 2010.

  1. DevilDog911

    DevilDog911 Light Load Member

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    Dec 26, 2009
    Lexington, Kentucky
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    I'm not sure how to word this but I hope someone can help me. I'm trying to figure out why CAT or Cummins ect ect haven't set up an engine that when your idling for a period of time (i.e. sleeping) that the engine shuts down like 4 cylinders. Can it be done??? It would kinda be like those chevy V8s that only use 4 cylinders when the whole engine is not needed. The cylinders that weren't firing would still be getting lubricated just no fuel. Thus it would have to lower the amount of fuel you would be burning while idling since you'd only be running 2 cylinders but yet it would still be enough to run the AC or heater and keep the batteries charged while running stuff off the inverter correct??? Like I said I don't even know if it would be possible. I would just think they could make the computerized engines able to do something like this. If it would not be possible please explain why so I can understand as I'm knew to trucking and don't know everything, BETTER YET I DON'T ANYTHING LOL about trucking. Thanks you all for taking time to read this.
     
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  3. BrainHurtz

    BrainHurtz Light Load Member

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    The I6 is one of the most fundamentally balanced engine designs. Running on less cylinders would cause it to shake like a mother *ffer... so I doubt you would be able to sleep through it.

    You could add a monster of a harmonic balancer on it but that would probably kill your driving fuel economy
     
    DevilDog911 Thanks this.
  4. Dutch

    Dutch Light Load Member

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    Cat did that back in the late to early 90's with the 3176 to save fuel and the engine would cut to 4 cyl. during cruising ran rough. Didnt last too long. The gm engines use solenoid hydraulic valve to control the engine valve lifters during cylinder deactivation and activation.
     
  5. ironeagle2006

    ironeagle2006 Road Train Member

    Had one of those trucks at Millis. I hated it. Put it to you this way GUTLESS would be putting it MILDLY. A Fleet 315 Cummins had more Balls than that engine did when it cut out. That and when it did the freaking thing wanted to throw you out of the seat from the Vibrations. Here is a clue how bad it shook take a 10lb weight add it to your LF Steer and try to drive at 60 MPH.
     
  6. DevilDog911

    DevilDog911 Light Load Member

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    Dec 26, 2009
    Lexington, Kentucky
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    I appreciate everybody's response so far and I understand what you all are saying but just couple more questions. Keep in mind I'm only talking about computerized engines.


    Okay I get that it shakes like a witch and driving one sucks. But I wouldn't want it to lose any cylinders while driving only while idling as in it wouldn't do it unless you flipped a switch or something. I'm not wanting the other for not to be moving they could still move up and down it's just when you flip the switch you'd be turning off the fuel to those cylinders, therefore saving fuel and since the non firing cylinders are still moving like normal in the engine that would make it stay balanced correct???
     
  7. walleye

    walleye Road Train Member

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    Land of Cheese
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    Mercury Marine used to make a outboard engine that shut down half of the cylinders at idle,.......
     
  8. Dutch

    Dutch Light Load Member

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    Nov 21, 2009
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    The cylinders stay moving regardless if you stop fueling the cylinder. What creates the imbalance is the engine compression. if you were to "shut those cylinders down" you would have a significant compression loss because we didn't fuel that cylinder, thus no combustion and gas expansion, creating the imbalance. The ecm would also increase fuel to the other cylinders to keep up for the loss of the non fueling cylinders to keep it from dieing.

    gm gas engines use hydraulic solenoids to control the hydraulic lifters to keep the valves close. The engine retains the exhaust gas from the combustion stroke and use it as a gas spring so to say to help keep it in balance,and they only do it during cruising applications. I would imagine that if they were to do this during idle conditions we would get a instability.
     
  9. Kansas

    Kansas Road Train Member

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    aircap, Ks.
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    My next APU, a good old Hit and Miss engine. No better way to piss off your neighbors lol:biggrin_255: They just dont use much fuel at all.

    http://www.youtube.com/watch?v=DOCBHa0UIsI

    Ray Wylie Hubbard said it best. "Some things are just cooler n hell"
     
  10. black_dog106

    black_dog106 Road Train Member

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    Google Coga truck idling. Sounds like an ole 2 cylinder John Deere idling. I dont know, but have heard it idles the way it does because there is so much fuel that computer doesnt fuel some cylinders, trying to keep idle speed down? I have no idea if this is the case or not, but it sure does make for some very neat and interesting flicks...
    http://www.youtube.com/watch?v=vHgLMkiTpDs&feature=related
    http://www.youtube.com/watch?v=yEuc3Sxmin0
    http://www.youtube.com/watch?v=Z8NYueci8VU&feature=related
    search youtube also, a bunch of good flicks there. Check out the races in Canada. Them Canucks put on quite a show...
     
  11. DevilDog911

    DevilDog911 Light Load Member

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    Dec 26, 2009
    Lexington, Kentucky
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    Thank you again for further explaining why to me. I now have a little more knowledge to this big world of truckin and Lord knows I still got a whole lot more to learn LOL.
     
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