from what i heard on the lockridge report was that a def tank thats frozen solid from a cold engine start, will thaw out and be ready to starrt injecting it within 50 minutes. EPA regs have a 70 min window before def injection must start.

Watkins Shepard is running the D13 Volvo Engine. I mean that one.

KH

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Kinghunter: Truck Photographer, Airline Guru and Boat Guru

RE: SCR

I have heard that the SCR/Urea system has a freeze point of 32F. How is this going to effect winter driving?

All of there automotive engines....including ISB, ISC, ISL, and ISX. Remember they did away with the ISM and now the ISX comes in two different displacements.

I do like that we're toning back the EGR. I believe from a driver's perspective, this will improve fuel economy while also improving performance. I say this because we will have better combustion while still meeting EPA standards on NOx because of the SCR.

I don't like the physical size of all of this. If anyone drives a truck with aftertreatment on it, you know the size of the whole system. The SCR catalyst will be the same size, and we still have to have both systems. Exhaust first runs through the DPF assembly to get all of the particulate matter out of the exhaust, and then runs through the SCR catalyst to break down the NOx. A lot of mounting options are available, but I still think this will be a hassle.

The diesel exhaust fluid (DEF) is 32.5% urea and the rest is water. This makes it freeze at around 12 degrees F. The DEF tank is heated by engine coolant, and the lines are electronically heated. Coolant also runs to the DEF dosing injector to cool it off. Once the engine has been running for the 70 minutes the Defront Heating Cycle ends. If the ambient temperature is not above 41 degrees F then a Maintenace Heating Cycle begins until ambient temps reach above 50 degrees F.

For anyone that drives a new Cummins, you'll know that if another maintenance item. The crankcase filter on these 07 engines have been overlooked, as far as I know....customers seem to not have read the owner's manual. Well, we have another filter in the DEF dosing unit (not dosing injector) that will have to be replaced when you schedule in a DPF cleaning or about every 200,000 miles. For midrange engines ISL and lower, there is also an air filter that gets replaced every service.

One thing that does concern me on these engines is reliability. We have many more parts now and thats always a concern. There is another computer, and about four more smart devices (like the vgt actuator) if I remember correctly. I believe that Cummins has most of it figured out, but a lot of the mounting and a few things like the DEF tank and lines will be the OEM's responsibility. I believe locating will be crucial for two reasons. One, I believe if the smart devices and new computer are mounted in a high splash area, this will cause a lot of electrical problems. I remember when Bendix ABS units were outside of the trucks, they had to replaced a lot of computers. Two, again its mounting but for the SCR system. We can't mount the SCR and DPF assemblies too far from the engine, or the exhaust will get too cold. Being these both are really big and awkward, this may be a problem.

Just my three cents.

Did not know about the cycles of the heated lines. Have you had a chance to drive a truck with the 15 liter in it yet?

not yet, have only seen one in person

Well, with the added cost of all this junk, the best solution is still a glider kit like a brand new FL Coronado spec'd out in every way you want and a rebuilt pre-egr DD engine in it. The pre-egr DD got the best fuel mileage when matched up to the right drive train and had a long useful life. And a brand new Coronado glider kit truck is about $30,000 less than a similar spec'd new Coronado with the latest emission engine. And it would be less $$ to operate over it's life compared to new emissions engines. Of course, for those that love to go to California, that wouldn't be a viable option after 2013. But for everyone one else, it will be a good option for quite a few years yet.