Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Jake brake vs. exhaust brake

Discussion in '1982-Present GM Diesel' started by Leadfoot, Jan 12, 2005.

  1. Leadfoot

    Leadfoot 1/2 ton status Premium Member

    Joined:
    Nov 28, 2000
    Posts:
    3,112
    Likes Received:
    1
    Location:
    Western Massachusetts
    Since there was some debate in another post, I thought I would start this one.

    The name "Jake Brake" came from the Jacobs engine brake.

    You can find out more info here:
    http://www.jakebrake.com/content.php4?doc_uid=3
    http://www.jakebrake.com/ppt/4


    Exhaust brake (also made by Jacobs):

    http://www.jakebrake.com/content.php4?doc_uid=25


    Also a "newer" technology (the bleeder brake):

    http://www.jakebrake.com/content.php4?doc_uid=122



    Jake brakes and restrictions:

    TAKEN FROM http://ks.essortment.com/jakebraketruck_raio.htm
    Many towns have signs with the words "Jake Brake" overlaid with the international symbol for "banned." I will explain what it is and why it is banned.





    The Jake Brake takes its name from the manufacturer who invented the most common implementation of the technology, the Jacobs Company.



    The Jake brake is an add-on engine brake for diesel engines. Big semi trailers, the 18 wheel trucks that move everything we use, can weigh as much as 80,000 pounds. Stopping them or slowing them down results in a great deal of wear on the brakes, which have to be replaced frequently. The Jake brake, as an engine system, causes no wear and tear and can help slow the truck before the wheel brakes need to be applied. Its primary use is on long downhill grades where the wheel brakes would otherwise have to be frequently pumped to keep the truck from gaining dangerous speed.

    bodyOffer(24828)

    When the driver presses a button in the cab to activate the device, two things happen. First, the switch excites the engine brakes' solenoids. By itself, this would help only a little but it is necessary for the second step. What happens inside of the engine goes roughly like this.



    As a four-stroke internal combustion engine, each piston in a diesel normally moves up and down twice in each cycle. For the nit-pickers out there, there are many two-stroke diesel trucks on the road as well. The process begins when the fuel and air valves are closed and the piston moves upward. This compresses the air in the cylinder to as much as 25 times atmospheric pressure. This is much higher compression than a gasoline engine (typically ten times atmospheric pressure) and results in the air getting very hot, about 900 degrees Fahrenheit. At this time fuel is sprayed into the superheated air which immediately begins burning. The second stroke, the power stroke, is the downward movement of the piston as fuel burns. The third stroke is an upward movement with the exhaust valve open to clear out the combustion products while the fourth stroke refills the cylinder with air.



    The Jake brake completely changes all this, redefining what the valves do as each piston moves up and down. With the fuel flow terminated, the upward moving first stroke still compresses the air to very high pressure. As we said above, this transfers mechanical energy into heat as the air becomes highly compressed. If nothing else were done, most of this energy would be recovered, except for frictional losses, as the cylinder moved back down and the compressed air expanded. The Jake brake, however, opens the exhaust valve just as the air reaches maximum compression, dumping all of that energy in an almost instantaneous explosive release. The result is a very effective slowing of the vehicle as mechanical energy is converted to heat and then dumped. The Jake brake effectively transforms the internal combustion engine into an air compressor.



    It has only one drawback: it is very noisy. You may have heard a semi use the Jake brake without realizing what it was. Sometimes when a truck is approaching a stop sign or stop light it suddenly emits a load roar, very much like a large lawnmower, for five or ten seconds. It is the noise that is causing many towns to ban the use of the Jake brake. Even though tests have shown the decibel level to be about as loud as a large lawnmower, at night or early morning the low frequencies seem to carry a long distance and are very noticeable.

    Because it extends the life of wheel brakes and saves money, trucking companies generally lobby against the bans and some towns are compromising by allowing the Jake brake to be used in daylight hours. Yet more and more signs, with the words Jake Brake and the international symbol for "banned", are certain to appear. Since the primary use of the Jake brake is to slow the truck on long downhill grades, the technology will continue to be widely adopted for use on the open road.
     
  2. BlueBlazer

    BlueBlazer 1/2 ton status

    Joined:
    Feb 15, 2001
    Posts:
    1,940
    Likes Received:
    0
    Thank you.:D Does that make sense Bobby?
     
  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,166
    Likes Received:
    1,363
    Location:
    E-town baby!
    Thanks Chris. As fun as a hi-jacked post can be it does make it hell to find the info later...wheras this will be at anyones fingertips with a logical search word. :waytogo:

    Rene
     
  4. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,095
    Likes Received:
    144
    Location:
    california
    :rolleyes: I know how a Jake works, I have even rebuilt a set once for goodness sake.
     
  5. 84gmcjimmy

    84gmcjimmy 1 ton status

    Joined:
    Dec 3, 2003
    Posts:
    12,838
    Likes Received:
    0
    Location:
    B.C. CANADA
    So they are so loud they have to be banned? But if it saves the trucking companies money by extending the life of the brakes, why can't the people accept that? :confused:
     
  6. BlueBlazer

    BlueBlazer 1/2 ton status

    Joined:
    Feb 15, 2001
    Posts:
    1,940
    Likes Received:
    0
    Whatever:rolleyes: You may have rebuilt them, but you still do not know what they do, but yet in your first post about them you act as if you are the authority around here on them. Please refrain from posting unless you know what you are talking about. Thanks:D
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,166
    Likes Received:
    1,363
    Location:
    E-town baby!
    I know there is a bit of ball busting going on which is OK...but please don't let this degrade into anything personal. I will not hesitate to lock this thread...

    To put a finer point on it, this is directed at Bobby and Tyler in particular.

    Disagree all you want, just stay civil.

    Rene
     
  8. Leadfoot

    Leadfoot 1/2 ton status Premium Member

    Joined:
    Nov 28, 2000
    Posts:
    3,112
    Likes Received:
    1
    Location:
    Western Massachusetts
    Thanks Rene.

    I posted in the other thread to correct a incorrect statement (I did not say the person who posted it was an idiot or had never rebuilt one himself, etc.). I have known what I was talking about and have not been able to put it into the correct words, so I know how it could happen. I just wanted to correct the "literary" portion of the statement. I also felt as Rene said, that this would be a good post for anyone wanting to do a search and nothing more. I did not intend to affend anyone with this post or try to prove a point. This was strictly informational.

    :thumb:
     
  9. big_truxx

    big_truxx 1/2 ton status

    Joined:
    Oct 8, 2004
    Posts:
    2,272
    Likes Received:
    0
    Location:
    Canaan, Maine
    Yes very good post indeedy!! :waytogo: :waytogo: (2 thumbs up for you.) I also have known quite some time how a jake works but lacked the ability to describe it to someone else. This post was the words of description needed!
     
  10. BlueBlazer

    BlueBlazer 1/2 ton status

    Joined:
    Feb 15, 2001
    Posts:
    1,940
    Likes Received:
    0
    Sorry Rene, I just hate when people spread misinformation, and I especially hate it when people can't admit they are wrong. ;)
     
  11. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,166
    Likes Received:
    1,363
    Location:
    E-town baby!
    No need for apologies...neither of you had crossed that invisible line yet. I just didn't want that to happen.

    Keep the info coming.:)

    Rene
     
  12. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,095
    Likes Received:
    144
    Location:
    california
    Grow up Bobby

    No personal shots Bobby. As a Mod I expect better from you, especially after I specifically warned both you and Tyler.:angry1: :angry1:

    Grow up!
     
    Last edited by a moderator: Jan 13, 2005
  13. divorced

    divorced 3/4 ton status

    Joined:
    Jul 20, 2004
    Posts:
    5,115
    Likes Received:
    0
    Location:
    .
    If the truck has a muffler(s) the jakes aren't very loud. Most people just have to have something to complain about - and who is better to complain about than the guys who transport everything that keeps you alive? Most of the towns that I have seen the "no engine brake" signs in are fairly flat and have speed zones somewhere around 35 mph. When a truck is slowing down from 35 mph the jakes don't really save much wear on the drum brakes, and it won't really slow you any faster in an emergency stop, so the jakes aren't really of any use as a safety item and that's probably why they are outlawed in some towns. If a truck has no muffler(s), just straight pipes, it will be very loud. I drove a truck for a while that had straight pipes and I would use the jake brake to slow down when going into small towns while dodging scales. A guy that lives about 1 mile before town and about 100 feet off of the highway chased me down one day and threatened to kick my a$$ because the jake brake scared his duaghter. I told him he could simply ask me to stop doing it instead of being an a$$hole about it and we have gotten along fine ever since.

    And where's the "other post" that started this?
     
  14. joez

    joez 1/2 ton status

    Joined:
    Oct 21, 2003
    Posts:
    2,512
    Likes Received:
    0
    Location:
    New Lenox, Illinois
    The other thread is there, its just working its way down the page. Might be on the second page depending on how your settings are.
     
  15. jarheadk5

    jarheadk5 1/2 ton status

    Joined:
    Mar 6, 2000
    Posts:
    4,389
    Likes Received:
    0
    Location:
    PA
    Generally, because people with more money than brains refuse to accept that:
    1. When you build your "Barbie dream house" on that perfect piece of land that just so happens to be near an active quarry, you're gonna have to deal with heavy trucks every day.
    2. The guys who drive the heavy trucks every day might actually know what they're talking about.
     
  16. smalltruckbigcid

    smalltruckbigcid 1/2 ton status

    Joined:
    Dec 25, 2004
    Posts:
    3,866
    Likes Received:
    3
    Location:
    NE Wyoming
    As someone else posted its noise that the people don't like, and to be honest some drivers go out of their way to make extra noise and really p*ss off people. There is 2 other types of auxillary braking systems that are quieter, but not as effective or as economical. One is the gate valve style that bolts on behind the turbo, works like a cork in a pipe by not letting any air out of the engine, its cheaper but doesn't have as much braking hp as a regular jake. The other is an elctromagnetic device that installs in the driveline behind the transmission and acts like a load generator in operation. Super effective braking hp but its heavy, not cheap to buy or repair, and is heavier than the other 2 by a couple hundred pounds. Sometimes weight is a factor for trucks.

    Heres some trivia for people...Clessie Cummins invented the engine compression brake after he retired from Cummins diesel engines company and they didn't want it when he brought it to them...so who did he get to manufacture them? Not Jacobs.:confused:

    The Singer sewing machine company. They were looking to expand the product line of a subsidary company that made drill chucks...yep the Jacobs drill chuck company is how the compression brake got called the Jake Brake.
    George
     
  17. Leadfoot

    Leadfoot 1/2 ton status Premium Member

    Joined:
    Nov 28, 2000
    Posts:
    3,112
    Likes Received:
    1
    Location:
    Western Massachusetts
    Clessie L. Cummins, founder of the Cummins Engine Company, conceived the idea of engine braking after a hair-raising and nearly fatal truck ride when his service brakes had faded from use. The event inspired Clessie to determine a way to use the engine and power that brought the truck up the hill so that it could be utilized to bring the truck safely down the hill.

    By virtue of a family connection, Clessie was introduced to the founders of the well-established Jacobs Drill Chuck Company. The two joined forces to further develop and produce Clessie’s vision – and thus, the Jacobs Engine Brake was born, as the Clessie L. Cummins division of the Jacobs Manufacturing Company was established.

    In 1961 the world saw the introduction of the first Jake Brake® engine retarder. The Jacobs Vehicle SystemsTM story begins here. Jacobs has subsequently forged an entire industry from a block of iron and the notion that the diesel engine, properly harnessed, can provide vehicle slowing power that reduces foundation brake maintenance and repair and improves truck safety.

    Over 40 years later, the same basic principles of varying the engine exhaust valve timing for engine braking are in use in nearly all over the road heavy-duty trucks. And Jacobs remains the leader, providing the highest quality, highest performance engine brakes on the market.
     

Share This Page