Ecodiesel power derating as temps rise?

[CrazyCooter]

The solution? Better cooling LOL....... be it oil, coolant, or both. You can't expect people to go only 45, you can't expect people who buy to tow to haul only 1,000 pounds.
The equation is pretty simple really - either lighten load, lower the speed - but there are practical minimums to each.

There are people that derated not towing and I've derated towing just 1100-1400lb in cooler weather!

I can't slow down much more, the climate is warming, I'm already traveling well under the rating......We definitely need a solution to ditch some heat!

I'd love to see a TSB and maybe an aux oil cooling package offered by Mopar for severe/police operation conditions that wouldn't void our warranty.

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[just_another_guy]

There are people that derated not towing and I've derated towing just 1100-1400lb in cooler weather!

I can't slow down much more, the climate is warming, I'm already traveling well under the rating......We definitely need a solution to ditch some heat!

I'd love to see a TSB and maybe an aux oil cooling package offered by Mopar for severe/police operation conditions that wouldn't void our warranty.

I don't think the oil temps are too far out of line in relation to the coolant temps, which are excessive. If you bring the coolant temp down, the oil temps will follow. If you only cool the oil, you will probably still derate when the coolant temps get too high.

 

[CrazyCooter]

I don't think the oil temps are too far out of line in relation to the coolant temps, which are excessive. If you bring the coolant temp down, the oil temps will follow. If you only cool the oil, you will probably still derate when the coolant temps get too high.

I could agree.

I was wondering if the oil was overloading the water side or is the radiator that undersized? When someone tows heavy this winter in near freezing temps we could have our answer? If coolant stays low and oil is still high, it's the oil side?

 

[just_another_guy]

I could agree.

I was wondering if the oil was overloading the water side or is the radiator that undersized? When someone tows heavy this winter in near freezing temps we could have our answer? If coolant stays low and oil is still high, it's the oil side?

You would see a bigger delta in the oil & water temps if that was the case. If you can keep the heads and cylinders cool with the coolant, the oil temp will drop as well.

 

[Red_5]

I'm new to this site and to Jeeps. I've wanted one my whole life and I'm finally in a place both financially and practically to get one. I've also always been a fan of diesels. This thread has me rethinking the Jeep with a diesel.

Did the person who opened up the hood "vents" on their Rubicon see any benefit? I have similar vents on my race car that are pretty effective. I highway speeds above the hood should be lower pressure than under the hood and that should extract hot air. I would think even at lower speeds having an opening to release hot air would be beneficial.

Next, from reading here, it seems like the particle filter regen is at least part of the problem.

I'm certainly interested in what modifications become available to address this problem.

 

[Hondo1]

I'm new to this site and to Jeeps. I've wanted one my whole life and I'm finally in a place both financially and practically to get one. I've also always been a fan of diesels. This thread has me rethinking the Jeep with a diesel.

Did the person who opened up the hood "vents" on their Rubicon see any benefit? I have similar vents on my race car that are pretty effective. I highway speeds above the hood should be lower pressure than under the hood and that should extract hot air. I would think even at lower speeds having an opening to release hot air would be beneficial.

Next, from reading here, it seems like the particle filter regen is at least part of the problem.

I'm certainly interested in what modifications become available to address this problem.

I didn’t see enough difference in hood vents to say it was worth while.

 

[foo.c]

That pretty much sums it up. You can't change how much HP you need to haul something, so there needs to be a way to get rid of the heat that comes along with it.

It's more complex than that.

Boost is heat. 8th gear will be the hottest when towing something heavy because it will be the highest load on the engine and also longer boost.

It's also about the torque that is being made to produce the work. You put less torque to the ground in high gear than low gear. The same amount of work is being done, but it's easier for the engine to do the work because the torque is being multiplied in lower gears. This can also translate to less heat.

So while it does take a certain amount of power, with an 8 speed there will be 2, 3, maybe 4 ways to generate that power and when you add boost to the mix I don't think X amount of power is always X amount of heat.

 

[CrazyCooter]

It's more complex than that.

Boost is heat. 8th gear will be the hottest when towing something heavy because it will be the highest load on the engine and also longer boost.

It's also about the torque that is being made to produce the work. You put less torque to the ground in high gear than low gear. The same amount of work is being done, but it's easier for the engine to do the work because the torque is being multiplied in lower gears. This can also translate to less heat.

So while it does take a certain amount of power, with an 8 speed there will be 2, 3, maybe 4 ways to generate that power and when you add boost to the mix I don't think X amount of power is always X amount of heat.

Boost is a product of the restriction between the turbocharger and the exhaust valve. Throw more fuel on the fire and the pressure will rise.

Any which way you try to talk yourself out of it, it takes fuel to move a load and more of it to go it faster. Fuel makes the heat not the air!

 

[ShadowsPapa]

Boost is a product of the restriction between the turbocharger and the exhaust valve. Throw more fuel on the fire and the pressure will rise.

Any which way you try to talk yourself out of it, it takes fuel to move a load and more of it to go it faster. Fuel makes the heat not the air!

Torque is only the ability to work - HP does the actual work and that's where the speed and load comes in. When building high performance gas engines we talk of the HP increase vs. the cooling capacity. We calculate estimated times and speeds based on the weight of the car vs. HP
Torque never comes into it.

 

[DailyMoparGuy]

I’m really enjoying this thermodynamics thread. Maybe it’ll inspire me to finish studying for my Thermal and Fluid Systems PE Exam….or not

 

[foo.c]

Boost is a product of the restriction between the turbocharger and the exhaust valve. Throw more fuel on the fire and the pressure will rise.

Any which way you try to talk yourself out of it, it takes fuel to move a load and more of it to go it faster. Fuel makes the heat not the air!

Compressing air heats it. Boyles Law or ideal gas law or some other law I forgot. This has follow on effects, such as hotter air across part of the radiator, hotter combustion temps, and so on.

Of course it takes fuel, unless you drive downhill.

I don't have a diesel or turbocharged vehicle anymore, but I know you are logging data. Try it and see if it show up in the data.

 

[foo.c]

Torque is only the ability to work - HP does the actual work and that's where the speed and load comes in. When building high performance gas engines we talk of the HP increase vs. the cooling capacity. We calculate estimated times and speeds based on the weight of the car vs. HP
Torque never comes into it.

It does in this case because we aren't using jet engines.

Your car accelerates faster in 1st gear than 2 second gear. Some amount of HP. Why? Torque multiplication. You put more torque to the ground in 1st, less in second, and so on.

 

[ShadowsPapa]

It does in this case because we aren't using jet engines.

Your car accelerates faster in 1st gear than 2 second gear. Some amount of HP. Why? Torque multiplication. You put more torque to the ground in 1st, less in second, and so on.

We aren't talking acceleration, but work actually done. In first gear that work is done slowly. You are using the torque to accelerate it.

 

[AXISJT]

I figured I'd just jump in here to talk a little about my experience. I just moved across the country CA to TN. I drove up into Utah through Colorado Kansas Missouri and down through Illinois and Kentucky. I had myself at 185lb my 120lb dog 10 full 20 gallon totes and some other gear for the trip. The outside temp going through Utah was topped at 105 and through Colorado at 98. I have been aware of the cooling issues with the diesels so was most nervous with Utah and Colorado because of the altitude and heat combo. But I am happy to report I had no issues what so ever and the trip mad me fall In love with the diesel gladiator even more. I watched my oil the whole time and the hottest I hit was 240. I stopped plenty of times to let the dog out and had no heat soak issues, and my mpg topped out at 32mpg. I know a lot have been having issues so I thought I would just give some good news

 

[just_another_guy]

It's more complex than that.

Boost is heat. 8th gear will be the hottest when towing something heavy because it will be the highest load on the engine and also longer boost.

It's also about the torque that is being made to produce the work. You put less torque to the ground in high gear than low gear. The same amount of work is being done, but it's easier for the engine to do the work because the torque is being multiplied in lower gears. This can also translate to less heat.

So while it does take a certain amount of power, with an 8 speed there will be 2, 3, maybe 4 ways to generate that power and when you add boost to the mix I don't think X amount of power is always X amount of heat.

It's definitely more complex than that, which is why I said it "pretty much" sums it up.

I don't have the compressor map for this turbo, but I imagine the efficiency islands are only a few percent apart like most turbos, so there's probably not much effect from that. The efficiency is key in this situation, because it's going to take X amount of fuel to make the required power, along with a certain mass of air, whether that mass is delivered at a higher pressure and lower RPM, or a lower pressure and higher RPM. Remember that air gets compressed anyway for the combustion process, and a 20 degree rise in intake temp only means a 20 degree rise in exhaust temps. It just doesn't add that much heat to the system.

It's known that engines operate at slightly different efficiency levels based on RPM, gearboxes have different losses at different ratios, turbos have different efficiency islands, etc. You can tweak all these variables and come out with slightly different outcomes, but they all end up being very similar. The situation you are describing above is simply running in a different gear, which I think people would have figured out pretty quickly if it had much of an effect.

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