Air Compressor

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Sanguinem Luna
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Re: Air Compressor

#11 Post by Sanguinem Luna » 07 Sep 2017 05:23

I've got a friend who's a truck driver for R+L Carriers in Utah, who hauls Triples. He's explained to me that the Air Brakes Simulation is nowhere near realistic. I've consulted him about it after encountering empty tanks way too often when trying to park (blindside backing, at least) and he had this to say: "Using your brakes actually does deplete some air from the tank, but the compressor replaces it so quickly that you never notice you used any. The instant that engine is running, that compressor is pumping out air. High idle, low idle. It's making air. The only way you would ever deplete your air tanks is you have a massive leak. Now, I can watch my primary air after a hard stop and it doesn't even budge. So, besides the obvious "where is that air going?" there's also the recovery time. Recovering about 1/2 of your air tanks, from idle, should take about a minute. And recovering 3/4 of your air tanks, from idle, should take 30 seconds. From dead empty, maybe a bit longer. 90 seconds or more for completely dry tanks. Sometimes it can take a little longer, but not usually. And while increasing RPM speeds it up, it doesn't really speed it up by much."

I also told him how sometimes, when setting the parking brake and quick traveling (back to a home garage, service station, taking ferrys, etc. Any kind of fast travel) that I would find my air tanks empty and need to build the pressure back up. He said this: "Now... if you set your parking brake, go home overnight (or leave the truck off for an extended period of time), then come back and you have empty tanks, that would be more realistic. That would also mean you need to chase down an air leak."

He drives a Peterbilt 386 Day Cab with a 500HP Cummins and a Manual 10 Speed. I'm not too sure if bigger trucks (Sleeper units or just longer frames) have larger tanks, but I imagine it wouldn't make much of a difference. So, with his insight in mind, it begs the question: "Why do we even have the so-called Air Brakes Simulation gameplay option, if it is actually unrealistic?"
Turnpike Double haulin' all day long. I love my job.
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Dukman
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Re: Air Compressor

#12 Post by Dukman » 07 Sep 2017 05:42

Luna has asked me about this several times and I finally decided to take a closer look at it.

Essentially this portion of the game is way off the mark.

For example in regards to refilling air tanks My current tractor has 3 main tanks, 2 primary and 1 secondary. (or something like that, I would have to ask the mechanics to be sure). On a typical day, my tractor leaks out 9/10ths of its air in about 16-18 hours. Complete refill of those tanks takes on average 3-4 minutes tops. Thats basically long enough for me to climb in and fill out my inspection sheet for the day. Then the tanks are full at 110psi and the truck is ready to go.

The air usage during backing? Fuhgeddaboutit, Completely off the mark. If I used air that badly, it would take me all night to put away my trailers because I would be stuck in place because I ran out of air.

You want realistic air usage? Then turn the setting off.

Does my tractor use air while backing or moving through the yard? Yeah it does, but Luna already described the situation and how my truck handles it. If my real tractor used air like the tractors in the game does, the tractor in question would be deemed unsafe and be placed out of service.



Addendum: Back on page one I see Reinhards reply about that setting being aimed towards the wheel and pedal crowd. While that does make sense to a certain degree, many of us use game pads that utilize pressure sensitive trigger for brake and throttle.
Last edited by Dukman on 07 Sep 2017 07:47, edited 1 time in total.

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natvander
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Re: Air Compressor

#13 Post by natvander » 07 Sep 2017 06:31

TheBigKangaroo wrote:
29 Jul 2017 08:10
I can drink 2 cans of VB (Australian 4.9%) waiting for the bloody thing...Ah...now I can tell my doctor it is this game that is responsible for my "less than responsible" drinking habits. .. There is always a positive to a negative !!!
There's your mistake. VB isn't for drinking.
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Dukman
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Re: Air Compressor

#14 Post by Dukman » 12 Sep 2017 04:23

Maybe beating a dead horse here, but I decided to record a video showing how long it takes to air up all the tanks on my tractor.

Tractor had been sitting for 9 days and all the air had bled off.

https://youtu.be/GPvCiyrxHpQ

So the air simulation/recharge in game isn't even close to accurate. Keep in mind, this time varies from tractor to tractor. Say if you have an older engine with a lot of miles/kilometer on it, that also means the compressor is old as well.

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Max
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Re: Air Compressor

#15 Post by Max » 12 Sep 2017 18:50

there are two basic timing in game. game time, that is in scale with map so like 1:20 on regular highway (1:3 in city). long tasks should be happening in this time to prevent boredom of players. second is physical time where simulation is running. this time is 1:1. it must be otherwise everything will be awfully off - truck moving, braking, turning, etc. simulation basics and short tasks are running in this time.

as game time is basically 1:20, if you slam the brake, you stop in few seconds in real time but in game time its like minute. you can hardly say you were braking for a minute in general.
question is what time are we using for what ...

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Bandit & The Snowman
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Re: Air Compressor

#16 Post by Bandit & The Snowman » 13 Sep 2017 18:18

Ok so you are using compressed time for the depletion of air pressure in the storage tank. Then why are you not also using compressed time for filling the tank again?

But the real point is: You have made depletion of air pressure depend on braking time, when in fact it depends on how much and how often the brake pedal is depressed and released. When the pedal is pressed, air goes from the main tank to the brake chambers, and stays there until the pedal is released again.

So, if the pedal constantly stays depressed in a certain position for an amount of time, no extra pressure is depleted over that time.

Where is the error?

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Max
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Re: Air Compressor

#17 Post by Max » 13 Sep 2017 19:24

there is no error.

i did not wrote a letter about how air is depleted. yet. if you try in game pressing and keeping pedal, you will see that this is not time dependent at all. amount of air consumed is just proportional to brake pedal position.

my analogy about braking process was just about time spend in braking process. just to illustrate that one thing can happen in 3 sec or 1 minute so you have to choose your perception. nothing less, nothing more.

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ShirBlackspots
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Re: Air Compressor

#18 Post by ShirBlackspots » 13 Sep 2017 23:22

When the brake pedal is depressed, there is supposed to be no air depleted in a properly maintained system. When people get their CDL, and go do their driving test, you're supposed to hold the brake pedal with the engine off for 1 minute as part of the precheck (in Texas, this pre-check test is supposed to take 45 minutes.) If no air is lost in that time, you pass.
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Max
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Re: Air Compressor

#19 Post by Max » 14 Sep 2017 03:20

that is not correct.

when you press brake pedal, there is depleted amount of air that moves into braking cylinder and keeps brakes - pressure in brake circuit/reservoir drops. all is stable then until you release brake pedal again. in that moment air in braking cylinder is truly released out but as gauges are measuring pressure in reservoir, no other change happen now.

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ShirBlackspots
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Re: Air Compressor

#20 Post by ShirBlackspots » 14 Sep 2017 03:30

Yes, that's what I meant. The pressure gauge isn't supposed to drop after you've held your foot on it for that period of time (after the initial drop when pressing the brake pedal)
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