mercedes sprinter chassis
we are downsizing from a diesel pusher to a class C. We had a tiffin before current one and the Wayfarer caught our attention, but when studying it a bit the 702 lbs carrying capacity killed it for u...
Forum Discussion
DRTDEVL wrote:
the invention of the Jacobs Engine Brake (Jake Brake). It opens the exhaust valves and closes the intake valves differently in order to create vacuum in the engine. The result of this is the loud B-A-A-A-A-A-A-A-A-A-A-A-A-A-A-P when going downhill or slowing down. Yes, some abuse these just to make noise, but its actually an important safety device.
Slight correction. An engine compression brake (aka Jake brake) works by allowing the piston to come up on the compression stroke-- it takes a LOT of energy to compress 18 or more "volumes" to 1. Then the exhaust valve opens, allowing all that compressed air to go out the exhaust. No fueling occurs during its activation.
With the throttle closed, engine compression brake OFF, the same compression occurs, but once the piston passes TDC, most of that energy is used to push the piston back down. So, with the exception of a small amount of friction, not much braking action occurs. No fueling occurs with the throttle closed (same as with engine brake or exhaust brake on).
Now, an EXHAUST BRAKE works basically like a "potato stuffed in the tail pipe". It provides back pressure (the amount speced by the engine manufacturer). The engine (basically a large "compressor" has to work harder/produce braking HP) to work against that back pressure.
