Re: [A/S] Exhaust brakes and Jake brakes

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

http://www.jakebrake.com

According to another page, http://www.howstuffworks.com/question134.htm
the big rig Jake brake alters the valve timing so the engine exhaust
valve opens when the compression is maximized in the cylinder. That no
doubt leads to a lot of noise. Jacobs also sells an exhaust brake for
Cummins and Dodge Ram that might be more a restriction in the exhaust
line without altering the valve timing, and I presume all shut down the
injection pump while braking, if the engine governor hasn't already.

I know I can hear Jake brakes on semis a mile or two from the nearest
interstate. They are very distinctive and LOUD. One truck driver on
another page (I found more than a thousand hits on "Jake Brake" on
www.google.com search engine) said they were only loud on semis with
straight pipes. The ones I hear are a lot louder than the engines.

Gerald J.