2020 Cummins IKE pull

4x4ord wrote:

ShinerBock wrote:

stsmark wrote:


I was wondering the same thing, it’s like the EB just gets shut off. Seems like it would be tough on some part of the drivetrain. Also if it just shutoff what’s holding the truck back from accelerating if not the brakes?
I find it interesting that neither of them point out how cool that brake hp indication is.

Engine braking at 3,500 rpm is what is trying to hold the truck back when it is off. It cannot with engine braking alone so it starts to gain speed past 35 mph and then the exhaust brake kicks back on to slow it back down to 35 mph then cuts off again. As you can see at of the video 5:56 of the video. Exhaust brake is off, it starts to get to 37 mph and then it kicks back on to slow it down to 35 again.

You can hear the exhaust brake. It's remaining constant. The exhaust brake/engine brake is really the same thing. While the engine is being driven from flywheel it is braking. The degree of braking varies with the speed of the engine and the amount of restriction in the exhaust. The exhaust brake is simply the turbo adjusting to create more restriction in the exhaust. It's like if you had an engine driving a positive displacement water pump and you had an adjustable nozzle on the end of the water hose. You could change the power demand on the engine by opening and closing the nozzle. The engine on these trucks is acting as an air pump and the adjustable turbo is the nozzle.

I'm not saying the exhaust brake is switching on and off when the gauge is displaying a value. I'm suggesting the wheel brakes are being applied to help with braking during the time that the gauge is displaying a value.

I don't here the exhaust brake being on constantly. In fact, I hardly hear it when it comes on in that video. I hear the normal sound of a Cummins(which is noticeably loader than the other trucks) at a high rpm, but I don't hear an exhaust brake being on the whole time.