i like how you give the answer right off the bat then explain instead of waiting till 10 min in to give an answer. it actually makes me watch longer because i hear the answer is "no" and i wonder why so i keep watching. proper way to do a youtube video👍
Great information and thank you, no Bless You for getting right to the point in the beginning. Your the only person who has done that, so I stayed and watched the entire video. Thanks again.
Edward Nelson **** this guy is a real fool. dont believe his bullshit. he knows nothing about jake brake retarded braking or even how engines work. he just a bullshitter.
7:44 that's the piece of the puzzle I have always been missing, that's why the Jake is SO EFFECTIVE, it works(consumes lots of kinetic energy) against compression and then against vacuum , double action. Whoever came up with the Jake mechanism, he guy was a FRIGGIN GENIUS. Thanks for clearing this out. I feel like some Mars Mission rocket designer scientist right now.
The ironic thing is those people who throw their vehicle in neutral downhill to save fuel, on top of losing all assist down the hill of engine breaking, will actually burn more fuel because with the trans in neutral it takes more fuel to hold the engine at idle rpm
It can actually save fuel though! Off course, if you're trying to decelerate or stay at a certain speed downhill, you might as well leave it in gear for the engine to assist in braking. However, on long level or very slight downhill roads coasting in neutral can actually save you more fuel than being in gear. This is because in neutral minimal fuel is being consumed to idle the engine rather than the engine in gear slowing down the vehicle and the driver having to accelerate again to maintain its speed. That is true for cars and light trucks at least. In fact latest model mercedes have a feature where the transmission does just that.
Awesome explanation and real-world data to back it up! I recently got a new(er) car and wondered why the RPM would jump and it would slow down significantly between 60-40km/h... The vacuum explains it! Thanks!
I found in a book years ago the engineering description of gas and diesel engines. Gas engines are "variable volumetric pumps" Diesel engines are "constant volumetric pumps". Once I found this description it actually put a lot of things into perspective when working on the different engines.
Hi guys, the Swedish brand Volvo trucks has a really great system for engine brake that's called VEB (Valve Engine Brake) that in principal closes all the valves and brakes the truck really good even with full load (60tonnes) or 132, 277.357 pounds/lbs of weight, when empty you don't even need the manual brakes at all if you use VEB at lvl 3 😁+extra the system uses the valves and a exhaust brake, so lvl 1 is only exhaust brake, lvl 2 only valve brake and lvl 3 both of them!
I liked the video and subscribed.... Because you got right to the point, and ended up watching the entire video anyway, haha. Thanks, lots of good info in your videos. Keep em comin.
Automotive smaller diesel engines have a butterfly valve on the intake which closes when you let off the throttle to create vacuum and also it closes on engine shut down to ensure a smoother shut down. Great video!
Adept Ape thank you for taking the time to explain your answer. I have always wondered about that very question and now I have been educated on the topic.
Yes I do enjoy your videos a bunch! Having had several E models and C-15s both single and 2 turbo models, I was reluctant to buy a C-13 Accert engine with high mileage. When the dyno came out good at a Cat dealer where I bought the truck, the guy explained to me about how deep the liner goes into the block on a 13, and it was considered a ''clean slate'' model by design, whereas a 15 has the very shallow liner protrusion depth and thus they are prone to cracking! Yes, I was able to experience ''hydrolock'' on a 6NZ I had at the time, and got to tow it and in-frame the whole engine at only 700,000! Please go over ''hydrolocking'' in a future video to explain to your viewers! Thanks and keep up the great work!
My boss kept telling me that using the Jake Brake is bad for the truck n it ruins the engine is that true? Please and thank you. Love the video n more of them new truckers should watch it cause as much as it’s helpful it’s dangerous as well just like the video says.
On a carbureted gas engine, the idle passage, and maybe part of the intermediate circuit, is AFTER the throttle plate. A high vacuum situation will pull more fuel through the idle circuit. This will result in a rich situation. When you are engine braking, assuming there is enough oxygen in the exhaust, it will backfire all the way down the hill. An air injection cut-off valve and/or a good (non leaking) exhaust system will limit this to an extent. In a fuel injected engine, the computers have been smart enough for the last 25 years to deal with this situation and limit the fuel. Engine braking in a carburated gas engine will result in lower fuel economy than rolling down a hill in neutral.
,,, Clessie Cummins invented the Jake Brake after he retired from Cummins . The management at the time, at Cummins, did not realized the huge potential, and Clessie with the connection of a relative hooked up with Jacobs in Connecticut (I think) and developed and brought the amazing invention to market. Its an amazing story, look it up .
Mr Cummins invented the engine brake to set a new coast to coast speed record, he had the power to stay at speed everywhere so all that was left was to find a way to go faster down grades without overheating the service brakes. Same as most automotive inventions it all started with the need for speed..
,,, the story I read had him on that famous coast to coast trip; however coming down Cajon their brakes failed and they narrowly avoided death. Waaaaay before Eye-15 . And this prompted the invention.
The jake or engine brake is basically a compression release. Not very many people really know how they work. If you can find a 2 stroke motorcycle from the 70s most had compression releases on the handlebar via a lever. When going down a hill if you pulled the lever it slowed you as well as sounding similar to a jake. It was just a valve in the cylinder head that opened and stayed open until you released it. It let more volume of air into the cylinder with nowhere to go except through the compression release or exhaust port. On a jake its the same except the air is passing through the exhaust valves
jake braking or engine braking is just turning you engine in to an air compressor hence the loud noise that they make when its in use.. cat, cummins and detroit engines use this very well for slowing down big payloads 70-100k lbs.. the mack engines don't use it very well as the are an smaller displacement engine tho there is one exception to that and that is the vgt that the newer engines now have
Good info and video as always.I think engine brake does not waste fuel while using it correctly ... But if you use it to often without needing it and then you have to put throttle down again and repeat that too much then probably you'll have to use more fuel to rev up again...
The logic is simple in a diesel engine with the jacobs brake on. If you remove the compresed air from the compresion chamber you do not inject any diesel fuel becasuse it will not ignite and will dilute the oil film + other consequences.
,,, it's more than logic, the engines can and do when something is wrong with the system throw fire out the stack when fuel is injected (inadvertently) with the Jake on, as the injection starts before the exhaust valves are cracked .
Look up "Telma" electric end brakes on driveshafts of European trucks and cranes. Amazing stopping power. I was driving a 180,000 lb Grove GMK 5300 crane down a steep grade and pulled Telma brake almost went through windshield. Not sure why American trucks don't use them?
The diesel engine has one draw back, especially 2 strokes, is that they will run on out of control. The Jacobs brake works on that principle minus fuel. I watched a guy at an asphalt plant throw his flannel on the air intake of a fully out of control 2 stroke diesel. The motor never even hiccupped, it swallowed the flannel into the turbo immediately. The color of smoke out his stack was slightly darker but it had no effect on engine rpm. It finally spun enough bearings and broke the crank. The damage was insane. One of those moments I look back on wishing cell phones back then had cameras.
Authority can Suck it with Authority the same thing happened to my F-I-Ls 82 Olds diesel! He put the pump together with the shut off valve in the wrong position! When it finally hit, it ran wide open for several minutes!! It had no turbo, and still sucked a flannel coat thru it!! Cut battery cables were no help. It got so hot that it blew the upper rad hose off, while my F-I-L was leaning over it! He was a big fellow, and it threw hit a pretty good bit! Vice grips on the fuel line finally got it shut down!! Just short of a complete melt down, I do believe!! But the engine was toast!! It shredded the accessory belts! Erupted coolant from the recovery bottle! Black smoke poured out the dual tail pipes! The noise it make was horrific! Probably burned up a 1/4 tank of fuel, before they got it shut down! My B-I-L was looking for his cigarettes!! He then realized that they were in the flannel jacket pocket, and marveled that the cigs were swallowed up, and consumed so easily!! I then reminded him of the flannel jacket!! The pack of cigs didn't have a chance!! I fully expected it to grenade!! But it didn't, surprisingly!! It even still cranked over, after it all cooled off! But never ran again!! We never took it part, to find out why!! It was like accidentally killing a neighbor!! We cleaned up! Disposed of any evidence! Replaced things as needed! And never spoke of it, afterwards!! My B-I-L once mentioned that he missed that coat! We just looked at each other, athe subject was changed, and the thought went away!! GOOD TIMES, I tell ya!! NOT!!
Even if it did, I'd rather waste a bit of fuel instead of, like, you know, dying. Also, what you said about storing energy by air, is actually how GM's active fuel management cylinder deactivation works. At least on the LS, what it does is it disconnects the exhaust valves on 4 cylinders at the bottom of their stroke and holds them shut. Because there is air trapped inside that cylinder, it now acts as a big spring, so instead of those dead cylinders being dead weight, instead it's helping the engine rotate the crank more easily. When the ECU wants 8 cylinders again, it reconnects the valves to the valvetrain and everything continues as normal. I'm not exactly sure *how* the connection/disconnection happens, only that it does. In 4 cylinder mode, those valves are no longer part of the equation.
When you brake, you are taking energy away from the vehicle. If you want to move again, you will need to use fuel to add the same amount of energy back. If you could predict traffic and stops perfectly, you could drive without any braking, saving a lot of fuel by only slowing and stopping when unavoidable. That's one reason why city driving uses a lot of fuel. Ofc no brakes = not safe. What about downhills? If your truck was indestructible, there were no speed limits and bends were built accordingly, you could get back all the energy used to get to the hill top. Driving a car on down that sale hill at the same time as the trucks would be frightening.
So, what happens if there's a malfunction, and fuel is introduced while the Jake is being used? I can say from experience with a cold Cummins Big Cam (The water temp was warm, but the oil hadn't heated up yet) that the answer looks really cool. I used the Jake for a moment, and hit the throttle again, and saw a flash. Just then, the guy going the other way got on the radio and said "Man! You just shot four foot of flame from both stacks!" After that, my warm up time doubled to 40 minutes before heading to the yard as that's the amount of time it took for the oil pressure to start dropping to normal. Still not sure that cold and thick oil was the cause, but I couldn't think of anything else that would cause fuel to load up in the exhaust like that, and it never happened again with double the warm up time.
DrFruikenstein A Jacobs brake, or the later version C-Brake (Cummins Brake) depends on oil flow into and out of the brake housing for proper operation. Cold oil might have delayed shutting off the injectors. Not quite sure how but that's the only thing I can think of. Today's engines being electronically controlled, that's not a problem. (To err is human, to really screw it up takes a computer)
@@cbmech2563 Thanks for the explanation. Now people will understand why I was fixated on the oil temperature. I should have explained that myself, but didn't. Thanks again.
Hey great video but what about the Diesel engines that DO have an throttle valve like the newer ISX and horrid DD engines and could you tell us why most engines after 07 have such quieter jakes it just sounds like loud hissing air especially on the DPF but a lot of regular muffled engines have next to silent jakes
,,, I generally ignore the existence of any Diesel with anything other than an air cleaner, cooler, and compressor wheel in the intake tract, lol. But, what's this ? 99 percent of the world market ?
Maestro gracias por Compartir con nosotros su sabiduría para k todos nosotros tus seguidores seamos MEJOR en la mecanica de ante mano muchas gracias y si pudiera aser videos en español GRASIAS
having to use any form of brakes means you were going to fast and wasted fuel to get there.So many kids love to play with jake to make noise.U usually a sign of inexperienced new jacks.
Wait, diesels might not do produce enginebraking through a vacuum. But instead they produce a lot of heat while the compressionstroke is happening. (which gasoline engines won´t). From a certain point, where the piston is now moving towards top dead center, the air exceeds the coolant temperature thus creating thermal energyflow from the compressed air in the cylinder to the coolant (the energy for this is provided by the kinetic energy of the vehicle). Even in case of non existing jakes, the pressurecurve past top dead center will now be as a result way below the pressurecurve before that. And from my own experience by comparing 2 cars of the same engine size and the same weight with N/A gasoline and turbodiesel, my conclusion is that enginebraking on a gasoline engine is way less powerfull than it is on a diesel engine. Even with a gasoline engines typically significant higher RPM´s.
,,, I agree, and will stick my neck out and say in the Diesel, with the Jake is engaged the compression is 70 percent and the vacuum is 30 percent of the braking, but this is an opinion. Also keeping in mind that the Diesel will generally have a half dozen or more points of compression.
Now I'm curious if open throttle plates in a Diesel would cause any restriction, some of the older Diesels use a choke shutoff, and there are aftermarket throttle kits to prevent engine runaway without using dioxide. Also curious to see which generates better performance for NA and forced inducted Diesels, cold air intake, short runner intake, ram air intake, etc.
interesting to see that no fuel is sprinkled while the jake is on. But how about you going down for a long hill, and diesel is not lubing the chambers? will that be an issue?
So there is a way that it wastes fuel out on the road if you leave it on all the time. When you lift off the throttle for bump or dips, shallow corners, etc. the truck slows down when all you needed was to remove torque from the dive axles for a couple of seconds. One the truck slows unnecessarily because the jake was left on you are now pushing extra fuel to get back up to speed. It’s to that the application of the jake itself doesn’t use fuel, but the real would use of it can impact fuel efficiency based on the way you use it.
Half-assed Garage I couldn’t agree more, but there are a lot of drivers that don’t truly understand how to use their jake. As a result they’re either under utilizing it, or they’re just leaving it on all the time.
aodhanof90 I leave mine on all the time. If I’m coasting or in no hurry to slow down I just rest my foot lightly on the clutch pedal. Nothing about it will cause reduced fuel economy.
aodhanof90 even if how you describe it is true, it's not the Jake Brakes fault, it's the drivers fault!! Plus, the drivers driving style would generally use more fuel, than even the wasted amount of fuel you are talking about!! Basically, the driver that does what you suggest, and causes wasted fuel, also drives in a manner that would cause even more wasted fuel!! A heck of a lot more fuel!! But, something else to consider! Even at a point that you have the jakes on unnecessarily, you would tend to push the throttle back down, as soon as you would notice it! You don't leave the throttle released (released throttle, means applied jake brake) to avoid a bump or pot hole, and stay off the throttle for just a second, but that would certainly engage the jakes, and you would certainly re-apply throttle immediately! The jakes were designed to perform a specific job! They were designed to provide braking assistance, while descending a hill, while heavily loaded, to prevent overheating the service brakes! Drivers now a days, use them in place of service brakes, especially when they think it's cool to make extra noise, to show off! There are some O/Os that swear that it reduces service costs, by not wearing out the brakes as quickly! Others swear that each use of the jakes causes a tiny bit of engine damage, and only operate them when absolute safety is necessary! The question of fuel economy is a simple one!! The specific idea of the use of a jake brake does not waste fuel! A drivers particular set of driving and jake usage habits, can!! There are some engine controller parameters, that help use the jakes during normal operation, that even help fuel economy!! I drove a truck once, that didn't immediately turn on the jakes for a simple release of throttle! You could leave them turned on, and the computer would not actuate them until a service brake application of at least one second occured! There are also parameters in the computers that when on cruise control, a set speed that gets exceeded by a certain number of MPH, would actuate the jakes! Say you cruise at 65, and then go on a downhill piece, and the vehicle speed exceeds 5mph over the set amount, the jakes would automatically engage an appropriate amount, to help slow you down, and prevent an overspeed situation!! Either legal speed limit, or company limited vehicle speed, or company appropriate speed!! I once drove for a company with 68mph governed trucks! Even in 70 mph states, you weren't allowed to exceed that speed, and had monitors on the units to report that info, when accessed! So, no 80mph downhill runs!! But, other ways to waste fuel, even greater amounts of fuel, exist, that should be addressed, before any thought goes into the jake brake possibility!!
Not really related but ...... Standby generators need to start up and go on load within about 15 seconds, even with a block heater it is not at working temperature. If a hot engine makes 700kw how much reduction in power is there just after start up?
,,, there is certainly less power available, because of the thick oil and heat loss to iron or aluminum, buuuuut the design has more power than the generator needs so the governor is just constantly adjusting for load or lack thereof.
@@elljay4587 you can hook an eld to anything, the eld working and being compliant with the mandates data collection are entirely different things. The lack of data to collect is the reason for the exemption of old trucks, not wether or not it would function and record drive time. I have 2 as well, 1 FLD and 1 old shit spreader.
Does engine braking clean carbon deposits? I suspect it does especially for extended declines..I drive a sprinter van and it seems to run better after a mountainous trip
Somewhat related question. I'm aware that most injection systems when placed in a zero load zero throttle "cut" injection. Now if injection is truly cut why don't I see EGT temps drop to idle levels? I can do this for extended periods on I70 coming off the rocky mountains and never see EGT's drop below say 600 degrees. Yet at idle EGT's drop to 325 degrees in short order, certainly less than 600 degrees in seconds. I would think while driving down a grade and injection events stopped the sheer volume of air running through without combustion would drop those temps in short order.
That is an interesting question isn't it. What are your rpm, boost, and Jakes on/off? You will usually have some boost just due to the fact there is a decent amount of air traveling through the turbo. The compression of the air by the turbo increases the temp a little, but I'm guessing that at higher rpms and due to the compression ratio of a Diesel, that air in the combustion chamber is pretty dang hot. The air itself ignites the fuel in these engines so it has to be pretty dang hot. That is my guess.
I would also be willing to bet it's hot compressed air. Air compressors only get to 150psi or so and think of all the heat they create at the discharge line from the head.
Yeah your dumping air hot enough to auto ignite diesel fuel rite at peak compression its hot as heck. When your burning fuel at idle little to no boost very lean fuel ratio the hot air of compression is then being used to ignite fuel thus cooling it some and becuase it is staying in the cylinder to do actual work it is cooled more and absorbed by the engine before it is final exhuasted at little to no pressure
AA - There is still combustion occurring within the combustion chamber while the Jakes are operating (at least on the older mechanical engines), and that permits the engine to maintain temperature. Decades ago during a descent, the engines not equipped with Jakes always realized a drop in engine temperature depending, the degree of which depended on whether the rig was equipped with an on/off fan or shutters. My question for you concerns cam actuated injectors, where the injector plungers would require a continuous flow of diesel for lubrication purposes, so are you certain that fuel delivery is curtailed during Jake Brake operation? I can understand where there would be no fuel injection on electronically fired injectors, it is just that I personally have not delved into the subject with much depth to see what is happening in those situations. So I am being lazy and asking you for the answer.
@@cwj9202 ,,, partial answer, if there is any combustion it is extremely small and not at all if there is no fuel, or ib double extremely rare maybe some engine oil .
I just have one question, so if no diesel fuel isn’t going in any of the cylinders why doesn’t the engine shut off? Great video and you are very good at what you do keep pumping out videos !
The engine it's being spin by the wheels, even w/o fuel it will act as if it has some injected in it. As soon as you press the accelerator pedal fuel turns ON.
My dad has a GMC 2500 with a Duramax diesel engine and he pulls a fifth wheel camper with a boat hooked up behind that, so a decent amount of weight. He told me that he doesn't use the exhaust brake (yes I am aware that is different from a jake brake, that's besides the point) because it makes the auto tranny downshift and makes the RPMs get high and it uses more fuel. I told him actually when you aren't touching the accelerator pedal it doesn't use any fuel at all, but he insisted. He said his MPG gauge on the dash always shows lower MPG when he uses the exhaust brake when he goes downhill. Is he right or just really stubborn?
I have a rather interesting question.i used to kill the engine and used the engine brake for my carburetted bike. does the engine still use fuel or does it squirt it and waste it inside the engine? and lastly but not least , is doing that bad for the cylinder walls and piston?
Can you do a video on the difference between a jake brake on semi vs the exhaust break on a diesel pusher RV. I plan on purchasing an RV in a year or so and need all the information I can get, unfortunately very little information out their other than it has one.
I've kinda got a question. So when you jake brake and the air comes out the exhaust why can't it be put back into the intake manifold. It would be hard to engineer and to make reliable but wouldn't it be quieter? Also why dose it have to come out the exhaust? Could they use the intake valve instead? That might be bad on the turbo and other components though. Loved the video thanks :)
gav well yes/no yes there are the exhaust fumes going back into the system but since there is no combustion going on there wouldn't be as much. And there not on all the time so that wouldn't be much of an issue. NGR systems basically do just that they such unburdened fuel back into the engine and they do it all the time instead of just for a few seconds.
You've already got a muffler on the exhaust, if the air came out the intake it would be loud as hell and need another muffler setup. - compressed air is hot, so if you were thinking of recirculating it, I don't think it would work as well, and that air would get screwin hot. Just a few other aspects.
Why don't they now design a way to make a Jake brake quieter? What type of half ass design in this? Airplanes have many noise quieting features and so do space vehicles but trucks are just big noisemakers? Are all the truck Engineers on vacation at the same time? Why not have a special exhaust system that is super quiet that gets engaged only for a Jake brake and then when power is generated in the engine, it goes back to the normal exhaust system?
Hey Josh, I have a question about Jake breaks... old school Cummins engines when you use the jake on a down hill you (DONT) hear the Turbo and say a Modern CAT or Detroit 60 you do hear the Turbo kickon? always wondered why that is
No, as I recall, the first truck to run with the Jake Brake was a gasoline tanker truck which operated on the West Coast. Clessie and son lived, I think, in Santa Rosa north of San Francisco at the time of the invention. I have talked with Clessie Jr. a few times over the years and last saw/spoke with him two years ago. He is an engineer through and through.
Chad Jessup That's very awesome! Bet he has alot of great stories! I knew about the tanker. Pretty sure it was a Kw. Thought they tinkered with the design/idea in the suburban. Model j maybe? Can't remember what engine, knew it was smaller
Randy, it was a KW, and I can't say that I have ever heard about the Suburban, but I do know that a Jake Brake was not designed for the J model Cummins, as it was a single head engine which would have presented many additional issues during development. Also, as the J model was not widely accepted within the trucking community, there would have been a financial disincentive to its manufacture. Are you possibly thinking of the old Packard with the U model Cummins (no Jake on that) Clessie used to promote the diesel in the early days?
I know your an cat certified mechanic. But call me crazy, but in order to downshift a gear, you have to rev the rpms up right? In other words it does burn fuel but not when the Jake or engine break is currently in operation. Just when dropping gears.
Your question is a little misleading. It is not the increase in RPM that burns more fuel. At a closed throttle position a gas engine uses the minimum level of fuel. A diesel at idle position injects the minimum amount to maintain engine rpm and most injector pumps if the rpm is higher than idle but the throttle is at idle inject zero. On both types of engines when one blips the throttle to assist in a downshift there is very little fuel used. Any fuel burned greater than what is needed to maintain creates usable power. When you are in gear this is what accelerates the vehicle. When one shifts all extra energy goes into accelerating the engine (or engine and transmission if power shifting). That really is a very minor load compared to the vehicle. As soon as you are back in gear after the shift you are also back into the minimum or zero fuel state regardless of RPM.
Happy b.s. productions I saw where you replied, I could not find it for a reply. Please note the that my reply did not at any time mention number of cylinders. Also notice that this video has both Gasoline and Diesel engines included. My reply stands, the same principles apply as stated to both diesel and gasoline. It takes very little energy to spin up an engine to assist in downshift and the fuel flow is at minimum when throttle is closed. The savings are observable in either case.
greenketch1 you are correct! Plus, if you are raising the rpm to downshift, the jake will not normally be operated!! If raised to the downshift point, and then the throttle is released, the jakes can operate, and slow the vehicle, in a more efficient manner, due to the increased engine rpm, and the lowered gear ratio!
Does that apply to a non electronic engine as well ? Say a B model. Or is there still fuel being sent to the nozzels when the throttle is in the idle position, and the Jakes are on ?
IF I SAY IF, system is wired and working correctly, foot off clutch and foot off throttle. You inject low idle fuel delivery. If wired incorrectly, you might want to clean out your underwear, it makes a heck of a noise and smokes. Possible engine damage.
Has anyone done a video where they turn off the truck to prove it? I know in modern fuel injection they shut fuel off using zero fuel. I know you can't do this on semi trucks because of safety concerns and they probably watching you in the trucks :D.
So my Kodiak with a vgt only works on the exhaust side of breaking, is not as efficient as the traditional Jake brake ? Or does the vgt also cut off the intake flow as well?
Little late here, I was just trying to figure that out myself. My guess is the pressurized air that gets released right before combustion creates enough exhaust flow that it spools the turbo a little.
,,, have to wonder if in some Diesels when you let off the throttle, but the rpm has not dropped to idle rpm, if the fuel system goes to no fuel or the very slight amount of idle fuel, as the revs are on the way down ?
Same thing. In a mechanical engine your governor controls fuel metering. You governor is just a set of centrifugal flyweights that fly open when your engine reaches a speed that allows the centrifugal force of the spinning weights to overcome a spring. Your throttle lever is attached to the spring, and as you push the throttle, it increases the pressure on the spring which means the governor weights (and therefore the engine) need to rotate faster to overcome the spring. The governor is attached to your fuel rack, and will automatically increase or decrease the amount of fuel all the way from no fuel to full fuel in order to hold the requested rpm. So if your going down a hill, and your off the throttle, it will drop down to the no fuel slot in the fuel rack.
Here's an interesting little tidbit people might like to know I'm going to use the year of 1972 caterpillar engines did not have a jake brake all Detroit's were two stroke and they never had no jake brake there were still a lot of 335 Cummins engines running around I don't know about caterpillar but on a Detroit you could let your foot off the throttle at any RPM and it didn't hurt the engine on the Cummins engine if you let your foot off the throttle and let the engine hold you on compression over 1500 RPM you could break head bolts you always run your Jake brake between 1500 RPM and 1800 RPM if you went over 1800 RPM at put a stress on things and you would break head bolts I can go on the other things that's necessary to make the engine last back then but my question now is why is it that modern engines you don't have to worry about this people get in their air ride truck with their air ride seats and their AC and their power steering they use the jake brake in any RPM they can just Mash on the throttle and nothing is hurt maldades these drivers wouldn't make it halfway across the country and their motor would be blown up so what is a safe RPM to run your Jake brakes if you want your motor to last how about these guys that use their jake brakes through town and they can't seem to be able to shift the truck without a jake brake how does that affect the long livity of some motor
Since there is far less cylinder pressure created when operating the jake brakes compared to normal running pressures under load, any head bolt breakage that occurred during jake brake operation was merely coincidental; so, any head bolt breakage while using the jakes would indicate the head bolt was already on its way out. I've seen more broken head bolts on engines without jake brakes than ones equipped with jake brakes. Use of jake brakes while shifting does not affect engine longevity, but it can affect transmission longevity. The old jake brake manuals stated the engine RPM should remain near governed speed for maximum retarding benefit.
FOOT OFF THE THROTTLE should be a indication that no fuel is being burned. Truck drivers are absolutely Dumb. Some cant even back up tucks. And the new guys (and girls) cant even shift because they went to school to learn automatic only. Anyway. if you are reading this. Whether you are a truck driver. Car driver, whatever. Do not croud or ride their ass.
It shouldn't(no combustion heat punishment). If anything it keeps them clean and moving inside their grooves because of the change from positive to negative pressure.
A malfunction or a not properly adjusted Jake could damage the engine, but this is very rare on most engines. Jakes working normally shouldn't cause any engine damage, of course I haven't seen engine damage from them.
Higher rpms will cause piston seizure or blow your turbo. I see rookies going down a mountain in a low gear but in a high mph then I see them at the shoulder, engine is blown. I have a c15 with 1.5 million miles. I never let the rpms go above 1800.
i like how you give the answer right off the bat then explain instead of waiting till 10 min in to give an answer. it actually makes me watch longer because i hear the answer is "no" and i wonder why so i keep watching. proper way to do a youtube video👍
The people who 'only want the answer' never ask the question.
Yeah I really like how be did that
Great information and thank you, no Bless You for getting right to the point in the beginning. Your the only person who has done that, so I stayed and watched the entire video. Thanks again.
Edward Nelson **** this guy is a real fool.
dont believe his bullshit. he knows nothing about jake brake retarded braking or even how engines work. he just a bullshitter.
That smart engineer is no less than Clessie Cummins himself. A self taught engineer.
Ace. Friggin hate 20 minute videos for a yes or no answer.
If I choose to watch the rest I might. I definitely respect That!!!
- That earned a subscription
7:44 that's the piece of the puzzle I have always been missing, that's why the Jake is SO EFFECTIVE, it works(consumes lots of kinetic energy) against compression and then against vacuum , double action. Whoever came up with the Jake mechanism, he guy was a FRIGGIN GENIUS.
Thanks for clearing this out. I feel like some Mars Mission rocket designer scientist right now.
I know this is an old comment but I believe the guy was Mr. Cummins
I wish all that could stay in my head, but I understood it for the first time.
Thanks...
Best part of the video was the end with your dog 😍
The ironic thing is those people who throw their vehicle in neutral downhill to save fuel, on top of losing all assist down the hill of engine breaking, will actually burn more fuel because with the trans in neutral it takes more fuel to hold the engine at idle rpm
Talk about endangering others and yourself . . . (O . O)
It can actually save fuel though! Off course, if you're trying to decelerate or stay at a certain speed downhill, you might as well leave it in gear for the engine to assist in braking. However, on long level or very slight downhill roads coasting in neutral can actually save you more fuel than being in gear. This is because in neutral minimal fuel is being consumed to idle the engine rather than the engine in gear slowing down the vehicle and the driver having to accelerate again to maintain its speed. That is true for cars and light trucks at least. In fact latest model mercedes have a feature where the transmission does just that.
@@nobenznofun9139 auto shift semi use neutral down hill as well.
@@GIGABACHI it also takes more energy to use the braking system than using the compression of the engine to slow the vehicle down.
putting it in neutral might even damage your gearbox! best to save as much fuel as possible is putting it in higher gear (if don't need to brake)
Awesome explanation and real-world data to back it up! I recently got a new(er) car and wondered why the RPM would jump and it would slow down significantly between 60-40km/h... The vacuum explains it! Thanks!
I already know this but I wanted to hear your explanation. You explained it very well.
I found in a book years ago the engineering description of gas and diesel engines.
Gas engines are "variable volumetric pumps"
Diesel engines are "constant volumetric pumps".
Once I found this description it actually put a lot of things into perspective when working on the different engines.
Subbed, been watching videos for a while now, you my friend are a wealth of knowledge.... Where's the t-shirts?
Hi guys, the Swedish brand Volvo trucks has a really great system for engine brake that's called VEB (Valve Engine Brake) that in principal closes all the valves and brakes the truck really good even with full load (60tonnes) or
132, 277.357 pounds/lbs of weight, when empty you don't even need the manual brakes at all if you use VEB at lvl 3 😁+extra the system uses the valves and a exhaust brake, so lvl 1 is only exhaust brake, lvl 2 only valve brake and lvl 3 both of them!
I liked the video and subscribed....
Because you got right to the point, and ended up watching the entire video anyway, haha. Thanks, lots of good info in your videos. Keep em comin.
I like how you included the gasoline engine in this video. good perspective on both operations of gasoline vs diesel.
I try to make the general question videos include both gas and Diesel if I can.
Automotive smaller diesel engines have a butterfly valve on the intake which closes when you let off the throttle to create vacuum and also it closes on engine shut down to ensure a smoother shut down. Great video!
Adept Ape thank you for taking the time to explain your answer. I have always wondered about that very question and now I have been educated on the topic.
Yes I do enjoy your videos a bunch! Having had several E models and C-15s both single and 2 turbo models, I was reluctant to buy a C-13 Accert engine with high mileage. When the dyno came out good at a Cat dealer where I bought the truck, the guy explained to me about how deep the liner goes into the block on a 13, and it was considered a ''clean slate'' model by design, whereas a 15 has the very shallow liner protrusion depth and thus they are prone to cracking! Yes, I was able to experience ''hydrolock'' on a 6NZ I had at the time, and got to tow it and in-frame the whole engine at only 700,000! Please go over ''hydrolocking'' in a future video to explain to your viewers! Thanks and keep up the great work!
My boss kept telling me that using the Jake Brake is bad for the truck n it ruins the engine is that true? Please and thank you. Love the video n more of them new truckers should watch it cause as much as it’s helpful it’s dangerous as well just like the video says.
Best Explanation of Jake brake ! Made it very understandable and really explained it. Thanks !
I've also seen on et that in the status it will say injection disabled when the Jakes are enabled
Awesome video! Really helps you visualize how the engine brake works
On a carbureted gas engine, the idle passage, and maybe part of the intermediate circuit, is AFTER the throttle plate. A high vacuum situation will pull more fuel through the idle circuit. This will result in a rich situation. When you are engine braking, assuming there is enough oxygen in the exhaust, it will backfire all the way down the hill. An air injection cut-off valve and/or a good (non leaking) exhaust system will limit this to an extent. In a fuel injected engine, the computers have been smart enough for the last 25 years to deal with this situation and limit the fuel. Engine braking in a carburated gas engine will result in lower fuel economy than rolling down a hill in neutral.
,,, Clessie Cummins invented the Jake Brake after he retired from Cummins . The management at the time, at Cummins, did not realized the huge potential, and Clessie with the connection of a relative hooked up with Jacobs in Connecticut (I think) and developed and brought the amazing invention to market. Its an amazing story, look it up .
I've heard in the past that Cummins developed it, but I've never researched the history. Thanks for the mini lesson.
Mr Cummins invented the engine brake to set a new coast to coast speed record, he had the power to stay at speed everywhere so all that was left was to find a way to go faster down grades without overheating the service brakes. Same as most automotive inventions it all started with the need for speed..
,,, the story I read had him on that famous coast to coast trip; however coming down Cajon their brakes failed and they narrowly avoided death. Waaaaay before Eye-15 . And this prompted the invention.
The jake or engine brake is basically a compression release. Not very many people really know how they work. If you can find a 2 stroke motorcycle from the 70s most had compression releases on the handlebar via a lever. When going down a hill if you pulled the lever it slowed you as well as sounding similar to a jake. It was just a valve in the cylinder head that opened and stayed open until you released it. It let more volume of air into the cylinder with nowhere to go except through the compression release or exhaust port. On a jake its the same except the air is passing through the exhaust valves
jake braking or engine braking is just turning you engine in to an air compressor hence the loud noise that they make when its in use.. cat, cummins and detroit engines use this very well for slowing down big payloads 70-100k lbs.. the mack engines don't use it very well as the are an smaller displacement engine tho there is one exception to that and that is the vgt that the newer engines now have
,,, I believe the Mack Dynatard moves the exhaust valve less than a Jake . But in effect very similar.
Good info and video as always.I think engine brake does not waste fuel while using it correctly ...
But if you use it to often without needing it and then you have to put throttle down again and repeat that too much then probably you'll have to use more fuel to rev up again...
The logic is simple in a diesel engine with the jacobs brake on. If you remove the compresed air from the compresion chamber you do not inject any diesel fuel becasuse it will not ignite and will dilute the oil film + other consequences.
,,, it's more than logic, the engines can and do when something is wrong with the system throw fire out the stack when fuel is injected (inadvertently) with the Jake on, as the injection starts before the exhaust valves are cracked .
Yes, when you shift down unnecessarily to use the Jake. No,while the Jake on.
Look up "Telma" electric end brakes on driveshafts of European trucks and cranes. Amazing stopping power. I was driving a 180,000 lb Grove GMK 5300 crane down a steep grade and pulled Telma brake almost went through windshield.
Not sure why American trucks don't use them?
Not needed american trucking service is basically on the style of "if it ain't broke don't fix it"
The diesel engine has one draw back, especially 2 strokes, is that they will run on out of control. The Jacobs brake works on that principle minus fuel.
I watched a guy at an asphalt plant throw his flannel on the air intake of a fully out of control 2 stroke diesel. The motor never even hiccupped, it swallowed the flannel into the turbo immediately. The color of smoke out his stack was slightly darker but it had no effect on engine rpm. It finally spun enough bearings and broke the crank. The damage was insane. One of those moments I look back on wishing cell phones back then had cameras.
Authority can Suck it with Authority the same thing happened to my F-I-Ls 82 Olds diesel! He put the pump together with the shut off valve in the wrong position! When it finally hit, it ran wide open for several minutes!! It had no turbo, and still sucked a flannel coat thru it!! Cut battery cables were no help. It got so hot that it blew the upper rad hose off, while my F-I-L was leaning over it! He was a big fellow, and it threw hit a pretty good bit!
Vice grips on the fuel line finally got it shut down!! Just short of a complete melt down, I do believe!! But the engine was toast!! It shredded the accessory belts! Erupted coolant from the recovery bottle! Black smoke poured out the dual tail pipes! The noise it make was horrific! Probably burned up a 1/4 tank of fuel, before they got it shut down! My B-I-L was looking for his cigarettes!! He then realized that they were in the flannel jacket pocket, and marveled that the cigs were swallowed up, and consumed so easily!! I then reminded him of the flannel jacket!! The pack of cigs didn't have a chance!! I fully expected it to grenade!! But it didn't, surprisingly!! It even still cranked over, after it all cooled off! But never ran again!! We never took it part, to find out why!! It was like accidentally killing a neighbor!! We cleaned up! Disposed of any evidence! Replaced things as needed! And never spoke of it, afterwards!! My B-I-L once mentioned that he missed that coat! We just looked at each other, athe subject was changed, and the thought went away!! GOOD TIMES, I tell ya!! NOT!!
Thanks,enjoyed the video,i understand engine braking much better,lol,looks like you were driving my 92 fld 425, 3406b
Even if it did, I'd rather waste a bit of fuel instead of, like, you know, dying.
Also, what you said about storing energy by air, is actually how GM's active fuel management cylinder deactivation works. At least on the LS, what it does is it disconnects the exhaust valves on 4 cylinders at the bottom of their stroke and holds them shut. Because there is air trapped inside that cylinder, it now acts as a big spring, so instead of those dead cylinders being dead weight, instead it's helping the engine rotate the crank more easily. When the ECU wants 8 cylinders again, it reconnects the valves to the valvetrain and everything continues as normal. I'm not exactly sure *how* the connection/disconnection happens, only that it does. In 4 cylinder mode, those valves are no longer part of the equation.
Fantastic explanation. Thank you.
When you brake, you are taking energy away from the vehicle. If you want to move again, you will need to use fuel to add the same amount of energy back. If you could predict traffic and stops perfectly, you could drive without any braking, saving a lot of fuel by only slowing and stopping when unavoidable. That's one reason why city driving uses a lot of fuel. Ofc no brakes = not safe. What about downhills? If your truck was indestructible, there were no speed limits and bends were built accordingly, you could get back all the energy used to get to the hill top. Driving a car on down that sale hill at the same time as the trucks would be frightening.
So, what happens if there's a malfunction, and fuel is introduced while the Jake is being used?
I can say from experience with a cold Cummins Big Cam (The water temp was warm, but the oil hadn't heated up yet) that the answer looks really cool.
I used the Jake for a moment, and hit the throttle again, and saw a flash.
Just then, the guy going the other way got on the radio and said "Man! You just shot four foot of flame from both stacks!"
After that, my warm up time doubled to 40 minutes before heading to the yard as that's the amount of time it took for the oil pressure to start dropping to normal.
Still not sure that cold and thick oil was the cause, but I couldn't think of anything else that would cause fuel to load up in the exhaust like that, and it never happened again with double the warm up time.
DrFruikenstein
A Jacobs brake, or the later version C-Brake (Cummins Brake) depends on oil flow into and out of the brake housing for proper operation. Cold oil might have delayed shutting off the injectors. Not quite sure how but that's the only thing I can think of. Today's engines being electronically controlled, that's not a problem. (To err is human, to really screw it up takes a computer)
@@cbmech2563
Thanks for the explanation.
Now people will understand why I was fixated on the oil temperature. I should have explained that myself, but didn't.
Thanks again.
The old 855 I drove was bad about the cold oil Jake wants to stay on
Hey great video but what about the Diesel engines that DO have an throttle valve like the newer ISX and horrid DD engines and could you tell us why most engines after 07 have such quieter jakes it just sounds like loud hissing air especially on the DPF but a lot of regular muffled engines have next to silent jakes
,,, I generally ignore the existence of any Diesel with anything other than an air cleaner, cooler, and compressor wheel in the intake tract, lol. But, what's this ? 99 percent of the world market ?
The flitters help reduce noise and the EGR helps dampen as well
They still make kinda loud or noticeable noise of a Jake kind of like a growl. I work around DD13s and MP 8s, they have gotten a lot quiter
Maestro gracias por Compartir con nosotros su sabiduría para k todos nosotros tus seguidores seamos MEJOR en la mecanica de ante mano muchas gracias y si pudiera aser videos en español GRASIAS
Excellent video very well your explanation greetings from Panama Central America.👍👋
Thank you.
having to use any form of brakes means you were going to fast and wasted fuel to get there.So many kids love to play with jake to make noise.U usually a sign of inexperienced new jacks.
Wait, diesels might not do produce enginebraking through a vacuum.
But instead they produce a lot of heat while the compressionstroke is happening. (which gasoline engines won´t).
From a certain point, where the piston is now moving towards top dead center, the air exceeds the coolant temperature thus creating thermal energyflow from the compressed air in the cylinder to the coolant (the energy for this is provided by the kinetic energy of the vehicle).
Even in case of non existing jakes, the pressurecurve past top dead center will now be as a result way below the pressurecurve before that.
And from my own experience by comparing 2 cars of the same engine size and the same weight with N/A gasoline and turbodiesel, my conclusion is that enginebraking on a gasoline engine is way less powerfull than it is on a diesel engine.
Even with a gasoline engines typically significant higher RPM´s.
,,, I agree, and will stick my neck out and say in the Diesel, with the Jake is engaged the compression is 70 percent and the vacuum is 30 percent of the braking, but this is an opinion. Also keeping in mind that the Diesel will generally have a half dozen or more points of compression.
Now I'm curious if open throttle plates in a Diesel would cause any restriction, some of the older Diesels use a choke shutoff, and there are aftermarket throttle kits to prevent engine runaway without using dioxide. Also curious to see which generates better performance for NA and forced inducted Diesels, cold air intake, short runner intake, ram air intake, etc.
interesting to see that no fuel is sprinkled while the jake is on. But how about you going down for a long hill, and diesel is not lubing the chambers? will that be an issue?
Thank you, in other words release of throttle turns the engine into an air pump that imparts a braking force on the output shaft (drive train).
,,, with a time release of quite a bit of potential energy, that would have otherwise went plus energy to the drive-train .
Older types of diesel are 2 stroke, and there are some newer 2 stroke 6 cyl. diesels.
My Toyota 1kz has a throttle butterfly but it still has a vacuum pump and more interestingly it only ever shows vacuum sometimes when decelerating.
Does it have a compression brake too?
Are there different types of jakes? I heard once that they can be exhuast, hydraulic, or electronically powered
We need a video on exhaust brakes now
So there is a way that it wastes fuel out on the road if you leave it on all the time. When you lift off the throttle for bump or dips, shallow corners, etc. the truck slows down when all you needed was to remove torque from the dive axles for a couple of seconds. One the truck slows unnecessarily because the jake was left on you are now pushing extra fuel to get back up to speed.
It’s to that the application of the jake itself doesn’t use fuel, but the real would use of it can impact fuel efficiency based on the way you use it.
I same would be true if you continuously rode the brakes.
You are correct, BUT you, the driver is the one wasting fuel if YOU let that happen.
Half-assed Garage I couldn’t agree more, but there are a lot of drivers that don’t truly understand how to use their jake. As a result they’re either under utilizing it, or they’re just leaving it on all the time.
aodhanof90 I leave mine on all the time. If I’m coasting or in no hurry to slow down I just rest my foot lightly on the clutch pedal. Nothing about it will cause reduced fuel economy.
aodhanof90 even if how you describe it is true, it's not the Jake Brakes fault, it's the drivers fault!! Plus, the drivers driving style would generally use more fuel, than even the wasted amount of fuel you are talking about!!
Basically, the driver that does what you suggest, and causes wasted fuel, also drives in a manner that would cause even more wasted fuel!! A heck of a lot more fuel!! But, something else to consider! Even at a point that you have the jakes on unnecessarily, you would tend to push the throttle back down, as soon as you would notice it! You don't leave the throttle released (released throttle, means applied jake brake) to avoid a bump or pot hole, and stay off the throttle for just a second, but that would certainly engage the jakes, and you would certainly re-apply throttle immediately!
The jakes were designed to perform a specific job! They were designed to provide braking assistance, while descending a hill, while heavily loaded, to prevent overheating the service brakes! Drivers now a days, use them in place of service brakes, especially when they think it's cool to make extra noise, to show off! There are some O/Os that swear that it reduces service costs, by not wearing out the brakes as quickly! Others swear that each use of the jakes causes a tiny bit of engine damage, and only operate them when absolute safety is necessary!
The question of fuel economy is a simple one!! The specific idea of the use of a jake brake does not waste fuel! A drivers particular set of driving and jake usage habits, can!! There are some engine controller parameters, that help use the jakes during normal operation, that even help fuel economy!! I drove a truck once, that didn't immediately turn on the jakes for a simple release of throttle! You could leave them turned on, and the computer would not actuate them until a service brake application of at least one second occured! There are also parameters in the computers that when on cruise control, a set speed that gets exceeded by a certain number of MPH, would actuate the jakes! Say you cruise at 65, and then go on a downhill piece, and the vehicle speed exceeds 5mph over the set amount, the jakes would automatically engage an appropriate amount, to help slow you down, and prevent an overspeed situation!! Either legal speed limit, or company limited vehicle speed, or company appropriate speed!! I once drove for a company with 68mph governed trucks! Even in 70 mph states, you weren't allowed to exceed that speed, and had monitors on the units to report that info, when accessed! So, no 80mph downhill runs!! But, other ways to waste fuel, even greater amounts of fuel, exist, that should be addressed, before any thought goes into the jake brake possibility!!
Not really related but ...... Standby generators need to start up and go on load within about 15 seconds, even with a block heater it is not at working temperature. If a hot engine makes 700kw how much reduction in power is there just after start up?
,,, there is certainly less power available, because of the thick oil and heat loss to iron or aluminum, buuuuut the design has more power than the generator needs so the governor is just constantly adjusting for load or lack thereof.
I spent a lot of years looking at one of those FLD dashes.
wally twixter I still have 2 to look at neither of which supports an ELD, very valuable.
@@elljay4587 you can hook an eld to anything, the eld working and being compliant with the mandates data collection are entirely different things. The lack of data to collect is the reason for the exemption of old trucks, not wether or not it would function and record drive time. I have 2 as well, 1 FLD and 1 old shit spreader.
Does engine braking clean carbon deposits? I suspect it does especially for extended declines..I drive a sprinter van and it seems to run better after a mountainous trip
Yes if you leave it on all the time you're slowing down and speeding up and slowing down and speeding up
Engine braking doesn't work on the intake stroke, it works on the compression stroke.
I was just wondering this the other day lol
Somewhat related question. I'm aware that most injection systems when placed in a zero load zero throttle "cut" injection. Now if injection is truly cut why don't I see EGT temps drop to idle levels? I can do this for extended periods on I70 coming off the rocky mountains and never see EGT's drop below say 600 degrees. Yet at idle EGT's drop to 325 degrees in short order, certainly less than 600 degrees in seconds. I would think while driving down a grade and injection events stopped the sheer volume of air running through without combustion would drop those temps in short order.
That is an interesting question isn't it. What are your rpm, boost, and Jakes on/off? You will usually have some boost just due to the fact there is a decent amount of air traveling through the turbo. The compression of the air by the turbo increases the temp a little, but I'm guessing that at higher rpms and due to the compression ratio of a Diesel, that air in the combustion chamber is pretty dang hot. The air itself ignites the fuel in these engines so it has to be pretty dang hot. That is my guess.
I would also be willing to bet it's hot compressed air. Air compressors only get to 150psi or so and think of all the heat they create at the discharge line from the head.
Yeah your dumping air hot enough to auto ignite diesel fuel rite at peak compression its hot as heck. When your burning fuel at idle little to no boost very lean fuel ratio the hot air of compression is then being used to ignite fuel thus cooling it some and becuase it is staying in the cylinder to do actual work it is cooled more and absorbed by the engine before it is final exhuasted at little to no pressure
AA - There is still combustion occurring within the combustion chamber while the Jakes are operating (at least on the older mechanical engines), and that permits the engine to maintain temperature. Decades ago during a descent, the engines not equipped with Jakes always realized a drop in engine temperature depending, the degree of which depended on whether the rig was equipped with an on/off fan or shutters.
My question for you concerns cam actuated injectors, where the injector plungers would require a continuous flow of diesel for lubrication purposes, so are you certain that fuel delivery is curtailed during Jake Brake operation? I can understand where there would be no fuel injection on electronically fired injectors, it is just that I personally have not delved into the subject with much depth to see what is happening in those situations.
So I am being lazy and asking you for the answer.
@@cwj9202 ,,, partial answer, if there is any combustion it is extremely small and not at all if there is no fuel, or ib double extremely rare maybe some engine oil .
I just have one question, so if no diesel fuel isn’t going in any of the cylinders why doesn’t the engine shut off? Great video and you are very good at what you do keep pumping out videos !
Zack Monosso I was thinking the same thing
remember the govener keeps the engine alive... at idling
Its above idle,in gear so the wheels are turning the motor. as soon as it gets back to idle the fuel system comes back on.
The engine it's being spin by the wheels, even w/o fuel it will act as if it has some injected in it.
As soon as you press the accelerator pedal fuel turns ON.
The engine cannot shut off because the diffs are turning therefore turning the transmission which is turning the engine over
My dad has a GMC 2500 with a Duramax diesel engine and he pulls a fifth wheel camper with a boat hooked up behind that, so a decent amount of weight. He told me that he doesn't use the exhaust brake (yes I am aware that is different from a jake brake, that's besides the point) because it makes the auto tranny downshift and makes the RPMs get high and it uses more fuel. I told him actually when you aren't touching the accelerator pedal it doesn't use any fuel at all, but he insisted. He said his MPG gauge on the dash always shows lower MPG when he uses the exhaust brake when he goes downhill. Is he right or just really stubborn?
I wouldn't say really stubborn
Just stubborn.
Now, you want stubborn ? My Father (RIP) ....
This is awesome, thanks
I have a rather interesting question.i used to kill the engine and used the engine brake for my carburetted bike. does the engine still use fuel or does it squirt it and waste it inside the engine? and lastly but not least , is doing that bad for the cylinder walls and piston?
Good video as always
Another great video from my favorite diesel RUclipsr
Can you do a video on the difference between a jake brake on semi vs the exhaust break on a diesel pusher RV. I plan on purchasing an RV in a year or so and need all the information I can get, unfortunately very little information out their other than it has one.
He has a video discussing compression brakes vs exhaust brakes.
Does cat use any variable turbos? I would like to see and understand more about them. Great video!
No they do not, even new cummins have gone back to a wastegate turbo
Jake brakes ONLY activate with no fuel on the accelerator, clutch pedal up fully.
the question should be-- does using the jake put more wear on the engine? the answer is YES.
If only I had your diesel knowledge; both of my trucks would be at 100%.
I've kinda got a question. So when you jake brake and the air comes out the exhaust why can't it be put back into the intake manifold. It would be hard to engineer and to make reliable but wouldn't it be quieter? Also why dose it have to come out the exhaust? Could they use the intake valve instead? That might be bad on the turbo and other components though. Loved the video thanks :)
It's not clean filtered air but air that is contaminated with carbon, some leftover exhaust, oil fumes, etc.
gav well yes/no yes there are the exhaust fumes going back into the system but since there is no combustion going on there wouldn't be as much. And there not on all the time so that wouldn't be much of an issue. NGR systems basically do just that they such unburdened fuel back into the engine and they do it all the time instead of just for a few seconds.
BOB White
The difference is the egr is government mandated, the other is designed to save the operator money.
You've already got a muffler on the exhaust, if the air came out the intake it would be loud as hell and need another muffler setup. - compressed air is hot, so if you were thinking of recirculating it, I don't think it would work as well, and that air would get screwin hot. Just a few other aspects.
Loud pipes save lives.
Before I even watch the video, I'll just say it doesn't matter. They are there to save the service brakes from extra wear and fade.
Enjoy your topics
I get better fuel economy with the Jake’s off and I mean noticeable 6.6 with 7+ off
Why don't they now design a way to make a Jake brake quieter? What type of half ass design in this? Airplanes have many noise quieting features and so do space vehicles but trucks are just big noisemakers? Are all the truck Engineers on vacation at the same time? Why not have a special exhaust system that is super quiet that gets engaged only for a Jake brake and then when power is generated in the engine, it goes back to the normal exhaust system?
Hey Josh, I have a question about Jake breaks... old school Cummins engines when you use the jake on a down hill you (DONT) hear the Turbo and say a Modern CAT or Detroit 60 you do hear the Turbo kickon? always wondered why that is
,,, my N-14 that is kinda old school will make 20 pounds of boost on the Jake @ 18 hun rpm, but I can hardly hear it .
And that very smart engineer? Clessie Lyle Cummins haha. Sorry had to add that.
His son, Clessie Jr., helped his father with the invention.
Chad Jessup wasn't it in an old suburban?
No, as I recall, the first truck to run with the Jake Brake was a gasoline tanker truck which operated on the West Coast. Clessie and son lived, I think, in Santa Rosa north of San Francisco at the time of the invention. I have talked with Clessie Jr. a few times over the years and last saw/spoke with him two years ago. He is an engineer through and through.
Chad Jessup That's very awesome! Bet he has alot of great stories! I knew about the tanker. Pretty sure it was a Kw. Thought they tinkered with the design/idea in the suburban. Model j maybe? Can't remember what engine, knew it was smaller
Randy, it was a KW, and I can't say that I have ever heard about the Suburban, but I do know that a Jake Brake was not designed for the J model Cummins, as it was a single head engine which would have presented many additional issues during development. Also, as the J model was not widely accepted within the trucking community, there would have been a financial disincentive to its manufacture.
Are you possibly thinking of the old Packard with the U model Cummins (no Jake on that) Clessie used to promote the diesel in the early days?
I used the exhust brake in going downhills.Diesel truck..
Was that engine you showed at the end seized up, or was it just knocking?
I know your an cat certified mechanic. But call me crazy, but in order to downshift a gear, you have to rev the rpms up right? In other words it does burn fuel but not when the Jake or engine break is currently in operation. Just when dropping gears.
Well essentially yes. But when you have throttle input the Jake brake turns off
Your question is a little misleading. It is not the increase in RPM that burns more fuel. At a closed throttle position a gas engine uses the minimum level of fuel. A diesel at idle position injects the minimum amount to maintain engine rpm and most injector pumps if the rpm is higher than idle but the throttle is at idle inject zero.
On both types of engines when one blips the throttle to assist in a downshift there is very little fuel used. Any fuel burned greater than what is needed to maintain creates usable power. When you are in gear this is what accelerates the vehicle. When one shifts all extra energy goes into accelerating the engine (or engine and transmission if power shifting). That really is a very minor load compared to the vehicle. As soon as you are back in gear after the shift you are also back into the minimum or zero fuel state regardless of RPM.
Happy b.s. productions I saw where you replied, I could not find it for a reply. Please note the that my reply did not at any time mention number of cylinders. Also notice that this video has both Gasoline and Diesel engines included. My reply stands, the same principles apply as stated to both diesel and gasoline. It takes very little energy to spin up an engine to assist in downshift and the fuel flow is at minimum when throttle is closed. The savings are observable in either case.
greenketch1 you are correct! Plus, if you are raising the rpm to downshift, the jake will not normally be operated!! If raised to the downshift point, and then the throttle is released, the jakes can operate, and slow the vehicle, in a more efficient manner, due to the increased engine rpm, and the lowered gear ratio!
Kinda still is. It'd be far more efficient to not slow down and just keep on rolling
1.5 speed
But what about modern turbo diesels in our cars?
hey bro I got a job at Quinn cat in southern California. i feel good
Congratulations.
hopper1 thanks.Its been my second week
Congratulations.
Adept Ape thanks
Woo hoo!
What's your thoughts on max rpm for long hill engine braking
Does that apply to a non electronic engine as well ? Say a B model. Or is there still fuel being sent to the nozzels when the throttle is in the idle position, and the Jakes are on ?
IF I SAY IF, system is wired and working correctly, foot off clutch and foot off throttle. You inject low idle fuel delivery. If wired incorrectly, you might want to clean out your underwear, it makes a heck of a noise and smokes. Possible engine damage.
how many hours to install a jake brake on a 3406b that never had one before
The only time i get black smoke out of my pipes is when my jakes are being used.... 3406e... 2ws model....
Who cares if it wastes fuel, it'll save your life
CAN YOU ACCELERATE WHEN YOUR ENGINE BRAKING IT IS BAD?
That's a freightliner classic, as my trainer used to say " this thing turns like a pig."
Has anyone done a video where they turn off the truck to prove it? I know in modern fuel injection they shut fuel off using zero fuel. I know you can't do this on semi trucks because of safety concerns and they probably watching you in the trucks :D.
So my Kodiak with a vgt only works on the exhaust side of breaking, is not as efficient as the traditional Jake brake ? Or does the vgt also cut off the intake flow as well?
Exhaust brakes are not as effective as engine brakes, they are however quieter making them a good choice for delivery vehicles/RVs.
Why does the turbo spool up when jakes are on?
Little late here, I was just trying to figure that out myself. My guess is the pressurized air that gets released right before combustion creates enough exhaust flow that it spools the turbo a little.
,,, have to wonder if in some Diesels when you let off the throttle, but the rpm has not dropped to idle rpm, if the fuel system goes to no fuel or the very slight amount of idle fuel, as the revs are on the way down ?
Roland Tamaccio I’m pretty sure on old mechanical diesels it still puts the idle amount in but electronic diesels cut it off completely I’m sure
Same thing. In a mechanical engine your governor controls fuel metering. You governor is just a set of centrifugal flyweights that fly open when your engine reaches a speed that allows the centrifugal force of the spinning weights to overcome a spring. Your throttle lever is attached to the spring, and as you push the throttle, it increases the pressure on the spring which means the governor weights (and therefore the engine) need to rotate faster to overcome the spring. The governor is attached to your fuel rack, and will automatically increase or decrease the amount of fuel all the way from no fuel to full fuel in order to hold the requested rpm.
So if your going down a hill, and your off the throttle, it will drop down to the no fuel slot in the fuel rack.
Roland Tamaccio not in some diesels, it happens in every Diesel engine.
,,, sooooo, ,,, as the rpm drops to idle, say 600 rpm, the fuel comes back to idle settings ? ,,, but not as the rpm is dropping from say 1500 rpm .
Roland Tamaccio research flyweight governors, it’ll explain how a mechanical diesels, steam engines, and lawnmower engines works.
It really doesn’t matter if it wastes fuel. It saves brakes.
Here's an interesting little tidbit people might like to know I'm going to use the year of 1972 caterpillar engines did not have a jake brake all Detroit's were two stroke and they never had no jake brake there were still a lot of 335 Cummins engines running around I don't know about caterpillar but on a Detroit you could let your foot off the throttle at any RPM and it didn't hurt the engine on the Cummins engine if you let your foot off the throttle and let the engine hold you on compression over 1500 RPM you could break head bolts you always run your Jake brake between 1500 RPM and 1800 RPM if you went over 1800 RPM at put a stress on things and you would break head bolts I can go on the other things that's necessary to make the engine last back then but my question now is why is it that modern engines you don't have to worry about this people get in their air ride truck with their air ride seats and their AC and their power steering they use the jake brake in any RPM they can just Mash on the throttle and nothing is hurt maldades these drivers wouldn't make it halfway across the country and their motor would be blown up so what is a safe RPM to run your Jake brakes if you want your motor to last how about these guys that use their jake brakes through town and they can't seem to be able to shift the truck without a jake brake how does that affect the long livity of some motor
Since there is far less cylinder pressure created when operating the jake brakes compared to normal running pressures under load, any head bolt breakage that occurred during jake brake operation was merely coincidental; so, any head bolt breakage while using the jakes would indicate the head bolt was already on its way out. I've seen more broken head bolts on engines without jake brakes than ones equipped with jake brakes. Use of jake brakes while shifting does not affect engine longevity, but it can affect transmission longevity.
The old jake brake manuals stated the engine RPM should remain near governed speed for maximum retarding benefit.
,,, The Jake, but not initially, became available for the two stroke 71's and 92's Detroit's .
99 7.3 Low oil pressure at high rpm help
gold
FOOT OFF THE THROTTLE should be a indication that no fuel is being burned. Truck drivers are absolutely Dumb. Some cant even back up tucks. And the new guys (and girls) cant even shift because they went to school to learn automatic only.
Anyway. if you are reading this. Whether you are a truck driver. Car driver, whatever. Do not croud or ride their ass.
What on earth caused that spun bearing?
11:20 Probably no oil or insufficient oil volume/pressure
I have a 3126 ser# 1wm25349 how can I get a turbo part #? 275HP rv is my engine a E or B ?
S/N 1WM25349
1523344 ENGINE AR COMPLETE
1208244 ENGINE AR-CORE
275 BHP AT 2200 RPM. FREIGHTLINER
TURBO 0R6923
TURBOCHARGER INSTALLATION KIT 4370080
STUDS if needed 8T7044
LOCK NUTS if needed 3E8017
Is it bad for RPM to go to 20?
Do the jake brake damage the piston rings by the time ?? I heard that if you use the jake brake
It shouldn't(no combustion heat punishment). If anything it keeps them clean and moving inside their grooves because of the change from positive to negative pressure.
Overspeeding will if you downshift too fast but that goes for anything.
A malfunction or a not properly adjusted Jake could damage the engine, but this is very rare on most engines. Jakes working normally shouldn't cause any engine damage, of course I haven't seen engine damage from them.
Higher rpms will cause piston seizure or blow your turbo. I see rookies going down a mountain in a low gear but in a high mph then I see them at the shoulder, engine is blown. I have a c15 with 1.5 million miles. I never let the rpms go above 1800.
cebuanoguy I do the same here!!
Who cares one way or the other.....your controlling your speed.....slowing down or stopping. You got use it