Ray,
Lester worked on some issues on my bus and really had an in depth knowlegde of a lot of systems. Worth the call.
http://www.prevoman.com/Pages/POGPolk/IMG_1938.jpg
Mike
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Ray,
Lester worked on some issues on my bus and really had an in depth knowlegde of a lot of systems. Worth the call.
http://www.prevoman.com/Pages/POGPolk/IMG_1938.jpg
Mike
Ray,
The more you post the more confusing this gets because in my coaches there is a house and there is a bus, and the two only interface at very few points. For CC to use their own custom boards to control things like a jake and cruise seems well out of the ordinary.
My coach has PLCs that funtion like your board to control the coach, but they have zero applicability to the Prevost systems.
If you want to talk to the guy that is alleged to know the CC boards try Buddy Gregg's Organization at 800-421-0031.
I also suggest you learn as much about your coach as possible for several reasons. First you will know who to go to for help. Second, you will be less likely led by the nose when it comes to repairs and paying for them, and last, you will learn there are a lot of things you can do when stuff goes bad and you will not have your wallet emptied on a regular basis. Trust me, what you will learn at POGII will be worth the time.
Jon, I would have expected the same. I wouldn't have throught that CC would insert logic in between the switches and the bus controls. But, today when I spoke with a technician at CC in Oregon, when I reiterated the problems my Prevost tech was seeing, including the jake, he indicated to me that he could "bypass the CC controls, and wire things such that the jake switches worked direct, rather than through the CC logic". In the next breath he told me that he felt the job to actually FIX the boards was 1 to 2 day job, easily done.Quote:
My coach has PLCs that funtion like your board to control the coach, but they have zero applicability to the Prevost systems.
In all fairness to the Prevost guys, they are really working hard to solve this, unfortunately with a system that has been evidently modified by CC, and no schematics, and limited telephone support for help from CC.
Amen to that ... :)Quote:
I also suggest you learn as much about your coach as possible for several reasons.
PS: Thanks for the phone numbers. I'll try to contact Lester tomorrow. I'll also post a call to Buddy Gregg's
This isn't going to be directly helpful, but here goes; various converters integrate their conversion into the shell at different levels; that is, the Angolas, for the most part were simply built on top of the the shell and it was pretty easy to figure out what side of the the coach a problem sat; either house or chassis.
A 92 CC that I was familiar with had its own OTR system which had a York compressor and an integrated electronics system on the aft panel of the front bay. It seemed that they had done a parallel construction of many of the electronic control systems similar to what they do on their plastic coaches. So in a sense, they were doing the high end conversion on a Prevost shell, based on their good experience with high end motorhomes.
I also had direct experience with a Foretravel where everything electronic in the engine and Jake went through the King Cruise Control. If that puppy went down, you were off the road.
Something to think about anyway. Gosh I wish I could be more helpful.
I had just gone back to two threads on the prevost-stuff site. The indication there was that without jake, while heading downhill, the pyro temps will go down substantially. But, if the jake was engaged in low one side would raise to 300-400 degrees, and that if high was engaged both sides would go up to 300-400?Quote:
The effect should be that the pyro temps drop substantially while the brake is in effect.
Am I misreading one of the posts?
Ray, you are correct.
When the jake is disengaged while coasting the pyros go to the bottom of the scale.
When the jake is engaged "low", one pyrometer will show a temperature and the other will be at the bottom of the scale. The jake when set at "high" will show a temperature on both pyros.
The temperature you see on the pyro gauges as a result of the jake being engaged is the hot compressed air being dumped into the exhaust manifold and is not the heat of combustion. Good catch.
Thanks for the clarification, Jon.
Someone is going to have to convince me on this one.
Riddle me this Batman;
If the engine is in a normal "idle' position whilst downshifted, is it not still burning fuel and such there is exhaust temperature related to the combustion taking place? Combustion equals heat equals some readable EGT?
If the engine is in a similar position with no fuel being injected into the cylinder, then what is the heat value of compressed air with no combustion components added? I have to think it is less than the above scenario? And if that is the case, isn't the EGT equal to the compressed air temperature less any losses due to heat transfer from the head to the location of the thermocouple that reads EGT?
Now I will admit that I haven't sat down and worked thru this as a thermodynamic problem, but at face value it doesn't make sense to me. But I have assumed incorrectly before. :o
If my interpretation of the pyros is wrong I hope someone will step in and slap me because I am going by memory here.
Under normal cruise conditions the pyros show the exhaust gas temperature at the exhaust manifold. They are reflecting the heat of combustion.
As soon as we decide to lift our foot from the gas pedal, the DDEC or diesel control reduces or eliminates the fuel delivery and the pyros go to the bottom of the scale. There is heat of combustion with the bus at idle but it is lower than the bottom of the pyro scale.
Now lets apply the jake brake. Under normal cruise conditions it is not working so the pyros show the normal heat of combustion. But when the foot is lifted from the gas pedal fuel delivery stops or is reduced and there is no longer combustion, and because of torque converter lock-up the bus momentum is now driving the engine rather than the other way around.
But the jake is engaged, so while the coach is driving the engine, the pyros show heat in the exhaust manifold. That heat is the heat developed, not from combustion, but from the compression of the piston stroke. And since the jake dumps that compressed air into the exhaust, rather than allow that stored energy to push the piston back down the cylinder, the engine has turned into a compressor, driven by the bus, with the compressed air going into the exhaust making a sweet sound, and increasing the manifold temperatures.
For those lucky enough to have a jake you probably have noticed that it works most effectively when the RPMs are high, and thus it is working the hardest providing the most resistance to the coach trying to push the engine, and the jake drops out at 15 or 20 MPH so the bus will not stall.
I should add that the reaon a diesel engine has combustion is because the compressed air is so hot it is capable of igniting diesel fuel injected into it.