DieselInfantry711
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Try this. http://pacbrake.com/exhaust-brakes-how-do-they-work-and-what-benefits-do-they-bring/
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Jake brakes open the exhaust valves just before top dead center allowing all that compressed air to exit out the exhaust. It also stops the fuel. So each time the piston is coming up to top dead center the engine is compressing all that air which requires HP and then just letting it go. It can really bring a heavy loaded trucks speed down fast but it is "loud" !!!I realize that I can probably Google it, but would someone please explain how this type of engine brake and a Jake Brake works?
Like I posted earlier in most modern engines with ECM's there is a signal that is sent telling the ECM to shut-off the fuel.Super, thanks for that.
When the engine is Jaking or Pacbraking, isn't fuel still being injected into the cylinders? Potential washdown or wet fuel in the exhaust that can ignite when you get back on the throttle? How is that handled, especially like in a retrofit as OP is building?
Jake brakes open the exhaust valves just before top dead center allowing all that compressed air to exit out the exhaust. It also stops the fuel. So each time the piston is coming up to top dead center the engine is compressing all that air which requires HP and then just letting it go. It can really bring a heavy loaded trucks speed down fast but it is "loud" !!!
An Exhaust brake is just a flap that partially or almost totally closes off the exhaust from the turbo which causes the engine to slow down. In the newer trucks it also shuts-off the fuel with a signal to the ECM.
That makes sense that a factory setup would have provisions for shutting off the fuel. I am not sure how OP will accomplish that or if it is not considered necessary, in which case I still wonder if even idle fuel accumulating in the exhaust could not pose a problem.Like I posted earlier in most modern engines with ECM's there is a signal that is sent telling the ECM to shut-off the fuel.
It's a "yes and no" kind of question. Yes there is excessive fuel going out the exhaust. No I don't think it will be hurt much except for exhaust emissions. Since we don't have to test for emissions that is not a problem. You can have a little problem if your exhaust is extremely hot and you unload a bunch of unburnt fuel into it. You can cause a stack fire which I've seen happen. It was on an extremely hot day and the truck had been used hard for most of that day. It just blew flames for a few minutes until all the fuel was burnt out. Didn't hurt the engine or even the exhaust.That makes sense that a factory setup would have provisions for shutting off the fuel. I am not sure how OP will accomplish that or if it is not considered necessary, in which case I still wonder if even idle fuel accumulating in the exhaust could not pose a problem.
Too bad there wasn't any time to sell tickets!IYou can have a little problem if your exhaust is extremely hot and you unload a bunch of unburnt fuel into it. You can cause a stack fire which I've seen happen. It was on an extremely hot day and the truck had been used hard for most of that day. It just blew flames for a few minutes until all the fuel was burnt out. Didn't hurt the engine or even the exhaust.
^^THIS is correct. There is a fueling mode called throttle leakage on the mechanical pumps and "motoring fuel" on electronic engines, Cummins anyway, other manufacturers have different terminology, but it is same same. It is there for a few reasons, one, if there is no fuel circulating, internals will be damaged. The moving parts in the injector are referred to as class fit, they are manufactured together as a unit so the contacting surfaces are uniform, clearances are in the .00001 range. If there is no, zero, fuel delivery, the parts will adhere to each other and you will have a failed injector(s). Think about how many times a single injector is fired at say 2000 RPM, no lube would kill it. Heat, one of the other reasons there is not zero delivery in an off throttle mode. The tip of the nozzle protrudes into the cylinder in a direct injected engine, compressing air to the point of ignition makes alot of heat, the leakage or motoring mode makes the cooling happen.Only an idle amount because you are not on the throttle.
Are you saying I'm spreading FUD ? Really ?!?!^^THIS is correct. There is a fueling mode called throttle leakage on the mechanical pumps and "motoring fuel" on electronic engines, Cummins anyway, other manufacturers have different terminology, but it is same same. It is there for a few reasons, one, if there is no fuel circulating, internals will be damaged. The moving parts in the injector are referred to as class fit, they are manufactured together as a unit so the contacting surfaces are uniform, clearances are in the .00001 range. If there is no, zero, fuel delivery, the parts will adhere to each other and you will have a failed injector(s). Think about how many times a single injector is fired at say 2000 RPM, no lube would kill it. Heat, one of the other reasons there is not zero delivery in an off throttle mode. The tip of the nozzle protrudes into the cylinder in a direct injected engine, compressing air to the point of ignition makes alot of heat, the leakage or motoring mode makes the cooling happen.
Don't spread FUD
OP will be fine, no fire out the tailpipe, with a flap style brake installed.
What's FUD?
Floridanson might be right, but I was figuring that the "D" was for data.Farting Under Darkness ?
Well when someone says I'm giving "FUD" advice that is not a very nice thing to say. The advice I give is from my decades of actually doing mechanical work. Not something I learned from reading a web site's tech column. If you disagree with something I have written that's fine. I will explain my reasons and usually back it up with actual technical reports. Not just my opinion. Mr. Wagner still has not presented any Technical documentation for his "opinion" will I have. At my age all I have left is my good name and when someone attacks that it does make me extremely angry. So I will leave this now. I will be contacting some friends at Cummins technical to see if they can send me some information on this whole thing.I would not make a good teacher. The way information is shared should be free to all without attitude or taking it personal. I much rather be a dumb azz about somethings and have the respect of all men then be a no it all and no respect.
Rustystud aka Greg Will has gained a lot of respect here by sharing info without attitude or taking it personal and you have shared a lot too but I think sometimes you take it to personal. Keep the respect and just share the facts.