What does "air to air" and "engine brake" mean?

[PNW_Steve]

Originally Posted by SolomonEagle

Just to clarify on auxiliary braking a little bit. The engine brake or "Jake brake" is a system that alters the valve timing to creat large amounts of back pressure adding resistance to the engine. Exhaust brakes add back pressure and resistance from a closable valve behind the turbo in the exhaust system. There are also electromagnetic driveline brakes that are pretty cool too

Random trivia:

Jacobs makes both the conventional "jake" brake and exhaust brakes like you describe.

[Brad_SwiftFur]

Originally Posted by Gustav

In order for that pickup to be rolled up like that, it had to be held stationary from the front. otherwise the green semi would have punted it forward into other cars or in the ditch. Notice the front end is pushed into the engine compartment. Likely was pinned behind a large trailer or similar. I have seen a lot in 45 years on the road, but nothing that intense. Just my opinion based upon a still photo with no other info.

Excellent observation, and quite correct. I looked up the article when I posted the photo, another photo (and the text) indicated there were 4 semis involved, 2 in the front, the pickup in the middle, the green truck behind it, which was rear-ended by the 4th. So yes, the pickup was pinned between the green truck and another semi in front of it. Photos show the upper part of the trailer in front of the pickup (including the roof) was pushed in a couple feet.

[Bigfoot18]

Originally Posted by kaivgrant

I'm looking at a bus for sale and it lists:

Air to Air: Yes
Engine Brake: No

What do these refer to? Thanks!

AIR TO AIR: Whenever molecules are compressed, it creates heat. The turbo charger on an engine compresses the air as it is forced into the intake system and causes it to become heated. If this heated air is then cooled, more of it can fit in the cylinder and more fuel can be injected thus increasing horsepower. AIR TO AIR describes the type of aftercooler or "intake air after the turbo charged phase". There are 2 types. One uses water and the other air. AIR TO AIR uses air. Its like a radiator. Hot turbo charged air passes through the inside like water through a radiator and then air passes through the fins and cools it.

ENGINE BRAKE describes a system that holds back the amount of exhaust gas that is released from the cylinders. Causing the engine to have internal resistance which causes a braking effect.

[Bigfoot18]

When I looked at the post, it only showed one reply. When i posted mine it showed i was #63. Sorry if I was redundant.

[Native]

Personally, I like your descriptions.

[Bigfoot18]

Originally Posted by Native

Personally, I like your descriptions.

Thanks.
Was a Field Service Cat Tech for many years. I can't do the work any more but still like to talk about it. All that diesel smoke kinda gets in your blood after a while. Now they don't smoke. Took all the fun out of turning the screws on an injection pump. Now you cant fool with them a whole lot. Put vice grips on the waste gate hose on the early C7's thats about it.