ENGINE BRAKING | How Semi Trucks Slow Down Without Brakes | SCIENCE GARAGE 

Science has shown that a Jake Brake is significantly quieter than an out of control truck crashing into your house.

We miss you Bart and science garage :(

I miss science garage!!!! Definitely one of my favorites!

Fact: every engine can get up to 15000 rpm at least once Edit: people are taking this joke to serious calm down

RU-vid is broken. My video released same time and also has no views, not visible in videos. Awesome RU-vid!

Holy hell. This dude can explain things so well. He's better than all of the teachers I've ever had.

Coming up to a tunnel? It's Jake Brake O'clock.

It is now June of 2021 and Bart with Science Garage was still the best show Donut did. Hope Bart is doing well over at Motor Trend but I miss him.

Jacobs Brake - Pissing off city council members and HOAs one neighborhood as a time...

Town Sound Ordinance: Keep quiet after 9 pm. Jake Brake: Hold my decibels.

Can proudly say I binge watched all 49 videos in this playlist in a week or so...and learned a ton of stuff along the way... Thank you so much guys This playlist is a great way to get into the basics, loved it

I love how he explains it as if I'm a 5 year old. He really cares, it's like he genuinely wants people to know this information.

i learn more from this than school thx sensei-donut for teaching me -life- about -cars- semi trucks

Ok who did the animations? The exhaust valve going up 😂👌

I was taught in transmission school that automatics even older style ones also have kindof an engine/trans brake. If youre going downhill and your brakes fade you can slam the trans from OD or D into L2 or L1 and it will actually apply extra bands and clutch packs and the engine will rev up to a certain rpm. But will not go further because the throttle is closed. Thats when the torque converter will compensate and slow the vehicle. The atf is cooled right after it leaves the converter to the trans cooler. You will not damage it. Ive tried that even on the poor 700r4 gm. It grabs the rear end and you slow down quick. So many people have died losing brakes going down a mountain and not knowing this engineered function of an automatic

I’m a truck driver and I love the new trucks jake brake, not the aerodynamic look, but the muffler is under the trucks so you can use your jake anywhere even where there are no engine brake signs because they don’t pop like stacks do (the exhaust pipes that go up and stick out over the truck) also the jake really has saved countless lives when it comes to steep mountains like West Virginia and PA

4 strokes of an engine: Suck Squeeze Bang Blow

A colab between science garage and engendering explained is needed now!!!

How to slow down without hitting the brakes: Step 1: let off the gas.

This was the last episode of Science Garage! Crazy! It's been over a year and a half. In these last few episodes he definitely seems less energized.

I never seen an engine valve open in this way 🤣🤣🤣🤣

I`m sorry to be one of those ``ehm actually`` people, but as someone who studies mechanics here in europe, and who drives a (european) turbo diesel manual every day, i will say this much: engine braking DOES very much occur in diesel engines, just maybe not in the same way as in gasoline engines (and said engine braking is VARY noticable in both my car and in the vw transporter vans we have at work, especially in 1st and 2nd gear), and the phenomena that occurs in diesel engines may be known by a different name on your side of the ocean. In diesel engines, the car will slow down when you let off the gas because of the high compression. Basicly the cylinder will fill up with air and the piston will compress said air (high compresstion btw), but, because you dont want to accelerate, little to no diesel will be injected, and with no bang to push down the piston, aside from the compressed air, energy will be lost, rather than produced, and the car will slow down. A turbo helps in this sence because the residual boost will give the piston more air to compress without combustion, and, once boost is lost, there will also be a vacuum which will likely have a similar effect to what a petrol does. Also, from my experience with a 1.5l turbodiesel vs a 2.2l petrol, my diesel slows down my car more violantly than the 2.2l sedan my dad owned until recently. Also, the reason trucks use jake brakes or exaust brakes isn`t so much that the engine isn`t able to slow down the truck at all, but rather that the weight and inertia of the vehicle are to much for compression losses alone to slow it down significantly, and aditional restrictions need to be added to the exaust to further slow down the crankshaft. Again, sorry for being ``that guy`` but (as you could probably tell from my wordy comment) i didn`t agree with alot of what was said in the video, and wanted to share my viewpoint on the situation, since I felt you werent being truly fair to diesel engines in general. Keep up the good work though.

I miss Bart and the Science Garage. Seeing this again years later brought back many memories.

Jake brake is the mating call of my people

i wish the diagrams were more accurate. for example the valves are opening the wrong way and even though it was stated that diesel engines dont have throttle bodies there was a throttle body on the diesel engine diagram. i hope no one gets confused by that kinda stuff

Can we get some more videos on semis. Like DEF systems, air brakes, and axle weighs

Now explain modern "exaust brakes" in small diesel engines

Small correction, in gasoline engine the fuel will be completely cut off if you are above certain RPM (like 1500), so no “idling fuel air mixture happens, just air. Also, instead of the power stroke you just compress air which will not cause the power stroke, which also helps the braking. So, vacuum and pressure slows it down, not just vacuum.

I've been trying to wrap my head around jake braking for years..I'm used to doing it, but I never understood what it does to the engine. Thanks for the clear explanation!

"that's a lot of Faygo" Michigan showing our reach

This is so sad that Science garage is gone this was my favourite show... now I'm stuck watching reruns to get by in life.

I’ve always used engine braking with my S4 and Stinger, and the later is even smoother because of the 8 speeds. Very often I slow down to the speed I want without even using my brake pedal. Nothing crazy, i.e. when getting out of the highway. Gives those brake pads more life!

Bart you will be missed, so does science garage :’)

BRING BACK BART AND SCIENE GARAGE! ME NEED TO KNOW MORE TO NOT MESS UP MY WHIP

I love this. I've learned so much from your channel. Two years ago I was mechanicaly illiterate. Now I work on my own car and even shade tree for friends on simple things. Thank you RU-vid University. And thank you donut team.

You guys should bring Bart back for a special episode. He’s the reason I fell in love with donut in the first place. He kinda taught me everything I understand about cars, he’s amazing

So you're telling me they don't stop by dropping anchor?? Doubt

Modern diesels DO have throttle bodies, but they are primarily for emissions/ EGR functions. They still don't control throttle. The ECU by means of electrical motor or solenoid controlled vacuum line can control the actuation of the butterfly valve in the throttle body to restrict the amount of fresh air (from turbo charger) into the intake manifold under low engine load situations. This helps create a pressure differential and thus helps the EGR system to feed more exhaust into the intake manifold.

I have drove a truck for 8 years. Started watching your vids to learn about racing because i think that may be my next step. Cool that you covered this as well 😁

I love watching videos on things I already know about. I get more than just book knowledge about it and I get to hear different explanations of the same thing. It increases my knowledge a bit more every time. This video is well made and I'm glad it was recommended to me.

*You:* _Jake brake_ *Me, as a 10yo intellectual:* _Look dad, truck farts! LOL_

Whoa, a late upload 👀 One of the best things about a manual transmission is engine braking. For daily driving, it's perfect

really miss this show, we actually watched these videos in my high school auto-shop class to learn the basics of a lot of stuff

Where science garage? Bro everyone who watches car stuff are nerds/geeks, we need this. We WANT this.

I love u guys. Been watching y’all since middle school, when I started getting into cars. Now I’m getting ready to go into the navy as an Engineman.

Absolutely great show. I wish you'ed been around when I was a kid with ZERO access to any info like this. Thanks dudes!

I feel like i am at physics class... You explain it like a hyped physics teacher

I've always loved Jake's. One of my favorite parts of driving a rig with straights. Preferably a Cat motor in a Kenworth W900L

Thanks for this video! I have always wanted to know about this!

Donut, y’all should do more videos on semi trucks. The people need to be informed!! Also you should teach people how to drive around semi trucks. Its ridiculous the crap that people do. 🙄

ive been watching videos in this channel since 2018, i was grade 8 student, and now im grade 12 graduating student, this gives me inspiration to pursue my course in college, im taking automotive servicing course, i wish you make more of this videos i will rewatch this videos as my reviewer....i learned a lot from this youtube channel, i love you science garage, i love you donut media

So basically its creating a vacuum that adds friction to the system thus slowing it down? Man what a time we live in, I literally heard the term "jake brake" 30 seconds ago and within 15 seconds I found an explanation on what it is! What a time to be alive, everything every little bit of info in the world is within arms reach.

So what I got from this is that diesels engine brake by farting

jake brake is the best sound in the world

Love that last, uber-succinct line. Very clear. Great video!

Miss this series and this guy. A+ series

*my boy a lumberjack now*

I miss science garage :( it was so fun and interesting

You can feel it in automatic cars that have a manual setting or paddle shifted. My car is automatic but I use the button shift sometimes especially if it is snowing out so I can control what gear the car is in better and to use engine braking so I can slow down without hitting the brakes and maybe losing control.

Where's this guy now

Trucker here. The reason that brakes can fail on trucks is because most of the trucks on the road in North America are drum brakes. As you apply the brakes the drum expands, and if you heat it up enough the drum will expand beyond the the stroke of the brake shoes and you literally have no brakes. The other failure that can happen is that if you apply constant, hard pressure to the brakes, you can heat them up so quickly that the components inside the brake drum and the wheel hub will catch on fire. Thankfully disk brakes are becoming more popular on class 8 trucks. Disk brakes can't get heat failure because the more the disk heats up the better they work. Of course you can still warp them or set them on fire, but with the better cooling its harder to do. Also runaway lanes work, but they're there to keep other drivers safe, not truckers. If you drive a truck up a runaway lane theres a very, very good chance you'll jackknife or flip.

73000 lbs? Here in Michigan it's legal up to 164000 lbs. Also, some modern diesels actually do have throttles, but I'm pretty sure that's more to do with emissions (especially EGR) than anything. Also, automatics can engine brake Judy as well as a manual, they just need to have a lock-up torque converter

Your back!!!! Yayyyyyyyyy missed seeing you around my guy

Very good explanation of the jake brake! Thanks!

I'm in my Freightliner Cascadia right now looking at snow in Kansas!

I love that one jake video in that square dash peterbilt long hood Caterpillar is one of the best sounding imo Edit- I realized I commented when this first released 🤣

This video is top quality and has insane clarity 10/10 explanation

What an excellent explanation! I never understood why semi trucks made that obnoxious noise to slow down, while my manual car or bike was nice and quiet. Now I do!

FACT: WE WANT MORE SCIENCE GARAGE

i am glad to see you have slowed down a bit and quit screaming all over the place. because of that, i subbed today.

Thank you for the video. I have studied this yet people still tell me a gasoline engine slows down from compression! I hope theyll be listening to you guys at least!

Bring back science garage The best and fun explanation

We diesel drivers can engine break without our Jake's, however it is less effective than a gas engine. During winter months when roads are slick we often avoid using our Jake's as they have a tendency to slide out our drives causing a jack knife. I like your analogy on the mechanics of the Jake break.

Is it just me, or does Bart look buffer with a beard

Thanks for the Bombfell ad! If I ever want shirts with sleeves that are 2" too short I'll check them out!

That was awesome! Always wondered about that… Thanks!

Miss this type of videos

The little hand explosion when he hits the table😂😂

My kids will enjoy the visual. Good job explaining Jake brake. You did forget to mention the displaced heat in the Jake process, though. Maybe in another video, then? Subscribing now.

This was SUPER interesting to learn-!

2:19 When the the gear is engaged, and you let off the accelerator from cruising speed, both rpm and speed will drop at same rate. There is no way in manual you can maintain the rpm while the speed is dropping without disengaging the gear. Only CVT can do that thing.

Simple depending on how strong your Jake's pull back,weight and gradient of the hill and select the proper gear say 15% grade on my truck at 50T or 110k lbs I'd sit in 8th with Jake's on stage 3. Should hold at 1900rpm

It's a good video for understanding how do engine brake work.. Thank you for the information..

Science garage is the best!!!! Keep up the great videos!

I just got my CDL permit today 💯

Bart the type of guy to dunk his donuts in beer 🍩🍺

This video is a year old, but it would have been nice if they also covered automatic overdrive. I think thats the same thing, but I’m not aware of the differences. This is one of the best explanations I’ve seen.

thxs I am a CDL driver and I really needed this knowledge

As a trucker engine braking is my best friend

This video took an hour to show up in my subscription feed.

Bart, you are the best teacher!

I miss this so much we need this back!

When he said I’ll wait for you to subscribe I was going too but realized I already was, I didn’t know that

Rpm gauge didn't move on the animation, in reality it will come down similarly with the rpm gauge not stay the same.

How come there’s no new episodes for Science Garage? This is such a great series!

Guys, please bring these back! ❤

The animation at 8:00 shows valves opening by moving UP

But the rpm andd the speed remain proportional always! As long as you keep the same gear ratio

where have you been man??? love those videos you made, very educational and funny, MAKE MORE VIDEOS BUDDY,

9:48 I love Faygo. I'm glad there is one store chain in Iowa that carries it.