so i pretty much have the concept of how exhaust brakes works but im still confused with a few things. ive heard that there is a slave cylinder on the exhaust valve, and that it opens the valve to release the gases there by slowing down the vehicle.... but what confuses me is how is this any different from a normal exhaust cycle. Either way the exhaust valve will open on the exhaust stroke with or without a jake brake...... Does the exhaust valve stay open longer? or maybe it opens sooner?? And does the camshaft have to play a part in it, does it use some special cam lobe for the exhaust brakes?? :Banghead so can someone please explain this to me
It is the exhaust valve opening early so when the cylinder fires, there is not the power generated on a normal cycle. That and the compression of the cylinder just before injection steals more power, and because there is very little power generated by the fuel, it winds up being a double whammy. I bet that is as clear as mud. George
The way I've understood it is the exhaust valve opens at the top of the compression stroke which is why you hear the pop. With that compression released and not forcing the piston back down, the other pistons approaching TDC become compressors until their compression is released as well. I haven't looked at the mechanics of it but I'd guess the camshaft is involved somehow. There are solenoids on the head which activate the exhaust valve at the proper time, driven by oil pressure.
To me an exhaust brake is a butterfly in the exhaust pipe. You seem to be referring to a Jake brake which is more effective but more complicated. Here is an old video. Somebody needs to do some better animation but the concepts are true. https://www.youtube.com/watch?v=7FSkNSOeTWM The engines that use an injector push rod to activate tend to have stronger brakes than those that use another cylinder's exhaust valve. The Cummins ISX has special cam stuff to make it even more powerful than usual. In the old days they were kind of an afterthought but more and more they try to make them as powerful as possible.
:drinkup very nice because of you all ive grasp the concept much better, and it seems alittle simpler now thanks very much