3 ms·

Also known as "jake braking". It's useful if you're a dump-truck driver who thinks midtown Manhattan is too quiet.

cartoonworld 5y ago
Jake Brake is engine braking, its really similar but not the same. Theres a difference between the kind of power braking/engine braking that a car does and a commercial truck. I typed a lot about this elsewhere, but essentially trucks have crappy brakes because of reasons (thermal ones, in large part) and as a result, in order to gather enough brake performance to not be extremely hazardous, they often must apply their engine brakes/jake brake/engine compression release brake in order to safely navigate with their loads in normal traffic or an emergency braking scenario (such as being cut off in midtown by some a-hole). https://en.wikipedia.org/wiki/Compression_release_engine_brake https://en.wikipedia.org/wiki/Compression_release_engine_bra...
deleted 5y ago
[deleted]
MisterTea 5y ago
A real "Jake brake" (Invented by Clessie Cummins) slows a truck down by turning the engine into an air compressor. It does this by modifying the exhaust valve timing to open at top dead center while cutting fuel. Once turned on all you do to engage it is to take your foot off the accelerator. That staccato popping sound is the compressed air blasting out of the exhaust valves. On old rigs like my '61 Mack the jake brake is switched manually. You have to be sure to turn it off once you get close to engine idle rpms otherwise the engine will stall. A quieter version called a bleeder brake which does the same thing though it leaves the exhaust valve slightly open during the entire compression stroke eliminating the popping sound. There is also the exhaust brake which puts a butterfly valve on the exhaust line creating back pressure when closed. Though the exhaust brake is known to cause problems with some valve train setups.

Jake Brake is engine braking, its really similar but not the same. Theres a difference between the kind of power braking/engine braking that a car does and a commercial truck. I typed a lot about this elsewhere, but essentially trucks have crappy brakes because of reasons (thermal ones, in large part) and as a result, in order to gather enough brake performance to not be extremely hazardous, they often must apply their engine brakes/jake brake/engine compression release brake in order to safely navigate with their loads in normal traffic or an emergency braking scenario (such as being cut off in midtown by some a-hole). https://en.wikipedia.org/wiki/Compression_release_engine_brake https://en.wikipedia.org/wiki/Compression_release_engine_bra...

deleted 5y ago

[deleted]

MisterTea 5y ago

A real "Jake brake" (Invented by Clessie Cummins) slows a truck down by turning the engine into an air compressor. It does this by modifying the exhaust valve timing to open at top dead center while cutting fuel. Once turned on all you do to engage it is to take your foot off the accelerator. That staccato popping sound is the compressed air blasting out of the exhaust valves. On old rigs like my '61 Mack the jake brake is switched manually. You have to be sure to turn it off once you get close to engine idle rpms otherwise the engine will stall. A quieter version called a bleeder brake which does the same thing though it leaves the exhaust valve slightly open during the entire compression stroke eliminating the popping sound. There is also the exhaust brake which puts a butterfly valve on the exhaust line creating back pressure when closed. Though the exhaust brake is known to cause problems with some valve train setups.