Hauling safety

[jk96]

jk96: Thanks for the link to 6.0 PS info. Interesting, but I'm not sure how much does or does not apply to the 6.4 L 2008 version.

No problem. While I don't know for sure, I would assume that the 6.4 is the same. I can tell you that I pull loads regularly in the 10-12k range with my 05 F250 powerstroke and am amazed how well this truck handles the loads. It has the integrated factory brake controller. With the combination of the brake controller and torqueshift, the truck handles great. Most of the time going down grades I barely have to use the breaks. Also, I had a guy pull out in front of me on a two lane hwy last fall. I was going 55 with a pretty good load and am still amazed at how quick and controlled I was able to slow the load down.

 

[Soundguy]

I havn't yet seen the integrated controlers, I just got the plug in wire harness kit for my Hop controller from TSC and slappe dit in my 04 f250PS.. works good.

Does the integrated controller give you the same controlls.. like panic switch, onset speed, and brake power?

soundguy

 

[jk96]

Soundguy,

Here's a pick I found online showing the factory controller. Its integrated into the dash.

I'm not familiar with any of the aftermarket controllers, but the ford factory brake controller is setup so that you can adjust the gain from 1-10 depending on how heavy the load. Also has a manual slide to manually apply trailer brakes. You can adjust your brake setting, then fully apply the brakes manually. If the trailer locks up your settings are too high and need to back it down a bit. This way you can set them up so that if you fully apply your trucks brakes, you get maximum trailer braking without locking them up. The harder you press the brakes in the truck, the harder the brakes are applied on the trailer as well. I'm assuming very similar to any aftermarket unit. Also has a green light when all connections are working properly, turns red and warns you if it detects a connection problem. (This can be a real PITA sometimes though since there's no way to turn it off - had to listen to my dash beep for 300 miles before having a chance to fix the problem, bad connection on one of the brakes)

jk

 

[patrick_g]

I havn't yet seen the integrated controlers, I just got the plug in wire harness kit for my Hop controller from TSC and slappe dit in my 04 f250PS.. works good.

Does the integrated controller give you the same controlls.. like panic switch, onset speed, and brake power?

soundguy

Soundguy, I too have the built in controller on my 2008 F-250 PSD It has a digital readout with +/- buttons to set braking power 1..10 which needs to be adjusted for the load. Too high and you slide the tires and too low you don't get all the braking you might want. It has a slide control to apply the trailer brakes manually from 0 to 100% by squeezing the traditional slide control between thumb and forefinger if you want trailer brakes without truck brakes.

I have the Tekonsha (sp?) unit on my Dodge with two control knobs to adjust the braking action and the slide switch to activate the brakes without using the truck brakes and think it is a terrific controller but the Fords built in seems to work just as good and I have had around 15Klbs on a tandem trailer behind the 2008 PSD F-250 and braking was good.

The main trouble I have with trailer brakes is forgetting to turn the brakes down after unloading and sliding them the first time I use the truck brakes, especially off road.

edit:

OOPS... Sorry jk your reply wasn't showing when I made my post. Only difference I see is that my truck has the readout to the left instead of to the right. Otherwise looks the same.

Pat

 

[Egon]

Thermodynamics!

The engines are well designed to dispense heat. On backing off the accelerator boost is diminished, the air is cooled, then compressed but the efficiency of the engine cooling system means energy is being taken out of the system faster than is being added.This results in a net braking result with the result with a locked up transmission.

Hows that for a fellow who really does not understand thermodynamics.

 

[patrick_g]

If you have read the above post (or even if you didn't) you are not REQUIRED to read the redundantly quoted material between here and the end of the quoted section.

Thermodynamics!

The engines are well designed to dispense heat. On backing off the accelerator boost is diminished, the air is cooled, then compressed but the efficiency of the engine cooling system means energy is being taken out of the system faster than is being added.This results in a net braking result with the result with a locked up transmission.

Hows that for a fellow who really does not understand thermodynamics.

Now start reading...

I'm sort of tentatively on board with your post, Egon.

Now please explain to me where the retarding force comes from.

I don't buy the high compression of the diesel. If the fire is out or small then the air being compressed gives back its energy on the "power" cycle. In coast mode, the pistons could just as well be compressing springs which would give back the energy stored in them on the down stroke. Friction of the moving parts is orders of magnitude less than the force we are trying to pin down.

So, the mystery is... Where does the retarding force come from?

Pat

 

[Egon]

During the compression stroke the engine cooling system removes more heat than is generated by the compression stroke. That should mean there could be a retarding force?

Thermodynamics were just not my strong point; in other words I didn't have a clue!

Maybe there are some magnets involved??

 

[Defective]

During the compression stroke the engine cooling system removes more heat than is generated by the compression stroke.

Have we found a solution to global warming???

 

[Egon]

Nope. No no fuel is being injected or burned!

Now tell us what is GLOBAL WARMING and all about it. From what I've read about 6000 - 7000 years ago the temperature was higher than it it is now???

And maybe explain why the our entire solar system is getting warmer??

 

[Soundguy]

The main trouble I have with trailer brakes is forgetting to turn the brakes down after unloading and sliding them the first time I use the truck brakes, especially off road.Pat

Same here.. I'll be backing up the flatbed to the dock at the feed co-op to get loaded, and will find I can't get the trailer to back straight.. then i rememebr the brakes are on, and making one wheel catch int he gravel better than another and makes her turn one way or another..... guy at the dock must wonder why sometimes I back up perfectly straight, and then the next month i'm all over..

soundguy

 

[patrick_g]

During the compression stroke the engine cooling system removes more heat than is generated by the compression stroke. That should mean there could be a retarding force?

Thermodynamics were just not my strong point; in other words I didn't have a clue!

Maybe there are some magnets involved??

Egon, I understand exactly to what you refer and applaud your lack of use of such terms as adiabatic in your description BUT the effect to which you refer is orders of magnitude less than the effect observed and reported and must be ruled out as THE main contributer.

Pat

 

[Defective]

Egon, I understand exactly to what you refer and applaud your lack of use of such terms as adiabatic in your description BUT the effect to which you refer is orders of magnitude less than the effect observed and reported and must be ruled out as THE main contributer.

Pat

So...

You mean we haven't solved Global Warming?

 

[Egon]

Pat, other than transmission somewhere in the realm of thermodynamics should lie the answer.

What's this "Adiabatic" thing?

I can recall seeing signs telling truckers to gear down when steep downward sloped hill was coming up so diesel engines must have some braking ability.

The other thing that perplexes me on a gas engine is that if the air supply is cut off there should be less fluid to compress and hence less braking power??

Defective: After this past winter I would surely appreciate a little warming!

 

[bjcsc]

What's this "Adiabatic" thing?
/

It actually means the opposite of what you were implying. An adiabatic process would occur if the temperature inside the cylinder changed as the compression changed and had no effect on the temperature of the block, i.e. net heat/loss gain = 0.

The other thing that perplexes me on a gas engine is that if the air supply is cut off there should be less fluid to compress and hence less braking power??/

That's interesting as what you suggest is that it would draw a vacuum on the intake stroke, and that coupled with the 50% lower compression ratio would yield significantly less resistance. Sounds plausible...Pat?

 

[patrick_g]

It actually means the opposite of what you were implying. An adiabatic process would occur if the temperature inside the cylinder changed as the compression changed and had no effect on the temperature of the block, i.e. net heat/loss gain = 0.



That's interesting as what you suggest is that it would draw a vacuum on the intake stroke, and that coupled with the 50% lower compression ratio would yield significantly less resistance. Sounds plausible...Pat?

I don't know, I seem to be running out of humorous material. I'm happy that at least one person got the adiabatic thing. It was yet another way of saying, "I don't think so, Tim!"

Egon, since engine braking on a gas engine is not produced by compressing (in the cylinders) the air entering through the intake, changing the quantity of it is not going to produce a big change in retarding force. The retarding force is the work the engine does on the intake stroke pulling air through a restriction (mostly closed throttle.)

The air compressed in the cylinders gives back most of the energy used to compress it. Might as well be springs instead of pistons in cylinders. heat loss in the compressed (AND HEATED) air is not a big factor as I said before. The heat is not that intense and the cylinders are not that cold.

Many if not most large trucks (signs referring to trucks ordinarily do not apply to pickups) are equipped with Jake brakes or equivalent. These brakes do very little in the higher gears compared to lower gears, hence a good reason to suggest trucks use lower gears. A diesel engine in a truck with no exhaust brake and no variable valve timing offers less engine braking than a comparable gasser.

Although retarding force may well increase by an order of magnitude or more by sufficiently down shifting a diesel truck and forcing the engine into significantly higher RPM, the retarding force is provided by friction of moving engine components and is still so weak as to not be useful in most heavy load or downhill situations. What is needed is an exhaust brake or variable valve timing (Jake brake .)

Once while descending from about 11,000 ft on a steep Forest Service road driging a nearly new Dodge-Cumins 1 ton with automatic, I was using 1st and 2nd gear only and was trying to be easy on the brakes, using them only intermittently to try to hold RPM down safely below redline trying to avoid brake fade. It was quite a descent. By the time I got to the bottom of the grade where there was a stop sign I didn't have enough brakes left to actually stop the vehicle short of the cross road. I will always be glad that the Ranger in the Gov truck ahead of me finally woke up and realized that the stop sign he had just been sitting at wasn't going to turn green and he drove on. I nearly hit him. After the brakes cooled they worked again, just fine.

I claim that there was no strategy that would have worked better as I was equipped and that the brakes on the nearly new truck were in fine shape but the task was just too demanding for them. Immediately after returning home from this trip I installed an exhaust brake. I have been down even steeper grades since with good control. I have taken my foot off the accelerator and coasted down a pass on the freeway in California at speeds exceeding 85MPH and been passed by a significant number of other drivers while doing it. With the exhaust brake I have gone down it in 4th and 3rd with neither a perfect match but both were OK. In 4th I exceeded the speed limit (70) just a little (not using friction brakes) and in 3rd we only went 50-55, a tad slow given everyone else's speed.

It may be hard for a flat lander to appreciate the dynamics of a heavily loaded diesel in steep grade and or heavy load situations. This is true whether towing or hauling. Towing can involve trailer brakes which will help if used judiciously and the grades are not too steep too long but hauling puts the whole problem on the truck brakes which in many instances are inadequate to maintain a safe profile irrespective of the gear used or the brake application strategy. In these instances you need more and that is where exhaust brakes are worth their weight in gold (oil?)

Pat

 

[Egon]

Lets go back to yesterday. The engine braking was still perplexing so I was off for a trip down the Google Enquiry road. That proved a dead end but I did encounter the Adiabatic term and some diagrams with strange looking equations attached to them. The diagram was neat and concise so it just may been an idealized version of what really happened in the engine!

Then it was on to home projects for the day. A P/U of slabed wood was cut to firewood length and another load was acquired. A few other necessary home chores were preformed and my aged body became tired and dehydrated. Hydration was imperative but home stores had been depleted. Upon arriving at the proper store it became obvious that it was a federal holiday and home sourced tap water would be the fluid of necessity.

Now on the trip home which is down a quite steep road on which my coasting bicycle can hit 80 KPH with ease it became obvious an empirical diesel engine braking test be preformed. This test indicated there were definite deceleration force's present.

More thought over the evening and thinking about the many tugs and the force required when pulling on the starting cord on my gasoline lawn mower engine with the throttle fully open and a screw driver holding open the choke started to make me suspicious of some of our previous statements.

Then it occurred to me the JAKE system changed the valve timing and my troubled thoughts turned to the camshaft timing and engine valve sizes.

My final conclusion is that the braking effect comes from differences in valve sizing, differences in valve opening and dwell characteristics.

Today it's armchair and rest time. There are limits the old system must adhere too!

 

[patrick_g]

Egon
40 years behind the times

40 might be too conservative and be an underestimate.

Pat