No such thing as Compression Brake for B Series

[kscheffler]

Seems like there has been a lot of discussions on "Jake Brakes" and it appears that the terms are not being used correctly. Based on a discussion that I had with my local Cummins dealer there is no COMPRESSION style brakes (exhaust valve release) made for the "B" series engine. Only option is an "exhaust" style brake (butterfly valve in the exhaust system). Is this true? I have read past postings on compression brakes but they must have been really discussing exhaust style brakes. Does anyone know of a compression style brake that we can use on our "B" series engines.

 

[RustyJC]

No, I don't know that the B-series Cummins was designed to use a compression brake. Yes, the Jacobs exhaust brake as marketed by Cummins and Dodge for the B-series Cummins uses the "Jake Brake" term - i. e. , a Diesel engine exhaust brake made by Jacobs. You and I may or may not agree with it, but they (Jacobs) own the term and can use it as they wish. Heck, the Dodge dealer who installed mine when I took delivery of the truck even stuck the decal in the back window advising the world that I have a "Jake Brake"!



Rusty

 

[Thomas]

From the Jacobs site:

"Jake Brake®" is a registered trademark of Jacobs Vehicle SystemsTM. The term Jake Brake is sometimes incorrectly used to refer to compression release type engine brakes in general. The term correctly refers to all of Jacobs Vehicle Systems retarding products including Jacobs Exhaust Brakes and Jacobs Driveline Brakes as well as Jacobs Engine Brakes.

FAQ7:

Will there be a Jacobs Engine Brake for the Cummins B or C engines?

ANSWER:



Jacobs Vehicle Systems is not developing an Engine Brake for these engines today due to low market demand and price considerations. Typically Engine brakes are applied to engines of 10. 0-L displacement and higher. There are Jacobs Exhaust Brakes available for the Cummins B5. 9, ISB, C8. 3 and ISC engines. For more information about the Jacobs Exhaust Brakes for Cummins B and C engines, visit our Medium Duty Exhaust Brake Applications and Performance page, or our Exhaust Brakes for the Dodge Ram page.

 

[kscheffler]

Thanks Rusty I agree the Jackobs terminology makes no sense at all. I also found out that Jackobs designer was one of the original designers of the "B" series engines and he went to Cummins with the original "Compression" style brake and they thought he was nuts. He subsequently quite went to the Jacobs company and they did not think it was such a stupid idea... kts

 

[Ethdee]

I believe that was Clessie Cummins.



Jim

 

[kscheffler]

So is it true then that there is no option for a compression style brake on the "B" series????

 

[dmurdock]

Yes, it's exhaust brake or no brake at all.

 

[David Oxland]

Why would you want the complication of a compression brake when the exhaust brakes work so well?

 

[csevers]

well

for the noise silly more noise is good

 

[Chipstien]

Re: well

Originally posted by csevers

for the noise silly more noise is good

LMAO:-laf :-laf :-laf :-laf :-laf

 

[WMeyers]

Clessie Cummins

kscheffler, Ethdee: Ethdee is correct -- Clessie Cummins was the designer of the Jacobs engine compression brake after he left Cummins and he first offered to license the design to Cummins.

 

[C Schomer]

It takes pushrod injectors to operate the real Jake brakes. They use hydraulics to open the exhaust valves at the top of the compression stroke so the piston sucks a vacuum on the power stroke. They're WAY more affective than the exh plug brakes! Craig

 

[RustyJC]

Actually, a compression brake works by releasing the compressed air charge by opening the exhaust valves at the top of each cylinder's compression stroke. This means that the negative work the engine does to compress the air before it is dumped is used to slow the truck. With no compression brake, the cylinders act like an air spring - the negative work done on the compression stroke is recovered (less friction, leakage and heat transfer) on the expansion (what would normally be the power) stroke.



The exhaust brake mimics this somewhat, but it creates negative work on the exhaust stroke as the engine tries to compress air against a blocked exhaust system. Because of the much greater fixed clearance in the exhaust system, much lower maximum pressures are achieved; therefore, an exhaust brake won't be as effective as a compression brake.



Rusty

 

[C Schomer]

Just like I said!!

 

[RustyJC]

Not to pick nits, but not really. The retarding force isn't due to the piston "sucking a vacuum" on the power stroke. It's due to the unrecovered work of compressing air on the compression stroke.



Rusty

 

[NVR FNSH]

Originally posted by RustyJC

Not to pick nits, but not really. The retarding force isn't due to the piston "sucking a vacuum" on the power stroke. It's due to the unrecovered work of compressing air on the compression stroke.



Rusty

Darn engineers Always gotta be sooo precise.....



Nice explanation BTW.



Brian

 

[bighammer]

I guess I thought during operatiion of a "jake brake" the exhaust valves stay open all the time. The engine just moves air and is not really compressing anything. Am I wrong? (again )

 

[kscheffler]

No on a compression brake the exhaust valve only opens at the top of the compression stroke...

 

[Paul Somers]

Most small towns around here have signs posted as you enter town: Warning, Jake brake illegal. Some of them make horrible noise.

 

[nickleinonen]

it is the compression brake on the engine that makes the noise. it pops the exhaust valve open just a bit near the end of the compression stroke, releasing the compressed air into the exhaust system. that is what causes the noise. . now, if the broker/driver has proper "full" exhaust on his rig, the compression brake is not too loud, but if it is a broker with straight pipes, then that c-brake will make a lot of noise. . the exhaust backpressure brakes shouldn't make much noise at all. at school, we had one engine in out heavy equipment lab, a volvo [12L{??}] that had both: a c-brake and an e-brake. . , c-brake for highway, e-brake for cities, kinda like how they have the air horns and the city horns. .