On 7/13/14, 12:06 AM, email@example.com wrote:
I looked it up, and I'm a little confused. I believe an engine brake
simply lets the compression out the exhaust valve, while an exhaust
brake saves it in a container. I understand the exhaust brake isn't
good for heavy-duty engines. I believe the jake is the former, the one
that simply lets it out the exhaust valve, and it's pretty quiet with a
proper muffler. Some truckers cheat and make a racket.
On Sat, 12 Jul 2014 11:28:05 -0600, Tony Hwang wrote:
No it is not required for big trucks.
While some similar hills have areas set aside for truckers, it is only
required to stop when posted.
Having been a US trucker, nationwide, there are only a handfull of hills in
the country where I will stop and check the brakes before going down.
Otherwise, if I can, I'll just stop at the top and sit for a minute or two.
On Sat, 12 Jul 2014 00:58:51 -0500, deadrat wrote:
Here's a simple experiment to confirm your stance on this.
Take a standard pickup truck, empty, to a race track.
Obtain a speed of 60mph and hit the brakes.
Measure the stopping distance.
Now load the bed with sand and repeat.
I"m sure you will find that it takes longer to stop.
Engine braking, on any engine, is using the compression of the
engine to slow down the vehicle. On gasoline engines it works pretty
easily by just closing the throttle and allowing the engine to try to
suck air through a closed door. Diesels do not have (generally
speaking) a throttle, so there is no "inherent" engine braking. An
"exhaust brake" plugs the exhaust, causing the engine to run as an air
compressor, which absorbs power and slows down the vehicle. A "jake"
brake works by controlling the exhaust valves, The exhaust valves are
opened just before TDC under no fuel conditions, evacuating the
compressed air into the exhaust. If the valve was not opened, the
compressed air would push the piston back down, recovering the energy
required to compress the air by returning that enegry to the drive
The air is highly compressed, when that valve opens it's a lot like a
backfire in a gas engine. The normal exhaust doesn't exit under
pressure, the valve opens as the piston starts coming back up and just
pushed the spent fuel gases out.
An exhaust brake is simple, it's just a simple valve in the exhaust.
Until now, I imagined that exhaust gas was under high pressure when the
valve opened. It makes sense that an engine would be designed for the
lowest possible exhaust pressure: more efficient.
My old BMW motorcycle was surprisingly quiet with unbaffled megaphones.
I guess the valves opened with less pressure than some bikes.
I would strongly agree that the training required to get a truck
licence is inadequate and there are WAY too many guys out there
driving vehicles WAY beyond their competence level. Get them into an
out-of-the-ordinary situation and they don't have a clue what to do,
On 7/13/2014 8:46 PM, firstname.lastname@example.org wrote:
It's been a lot of years. I remember hear about a
driver who was tired. He got his rig up to 70 MPH
and put the cruise control on. He left his 10 year
old daughter at the wheel, and went to the sleeper
to zone out. The road had a construction area, and
the daughter tried her best, wrecked the truck on
the side of the road.
You can depend onsomeone cutting you off and taking away your buffer
zone - so you NEED to adjust your speed accordingly - approach the
downhill at reduced speed - preferably close to "control speed" so the
brakes are not required to maintain the speed. A good Jake can be
worth it's weight in gold.
That is also an abuse of police power too. A little common sense and
a quick conversation when the drive came out should have resolved an
incident like that.
I know of a case where the driver was at a highway rest stop. OK, he
had to drive to get there to sleep it off, but this was not the case
here. And cops wonder why a lot of people hate them and don't trust
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