I normally work on Detroits and today I had to do a valve adjustment on an Cat C13 ACERT engine with the Variable valve actuators on it and it made me wonder. Why the heck didnt they just go with the EGR system like detroit 60 series has? Is there somthing Im missing or is this just a retarded setup.

 

Cat has to be Cat and do everything differently. For this reason, it is likely they will not be in the on-highway engine business after 2010. All the other engine OEMs laughed at and continue to laugh at Cat's technology. Why reinvent the wheel when it can't be any more round than it already is.

 

I heard a rumor that Cat was trying to buy out International just so they would have a home for there engines.

 

EGR on a diesel engine will fill up the intake manifold with soot, clogging it. I clean them out all the time on the VW TDI.
If Cat has come up with a way to get EGR without actually having to use EGR plumbing, I think it is a great idea. If they close the exhaust valve early, that would do it nicely and you woudn't have to deal with all that sooty exhaust being re-routed back through the intake.

 

I don't think that will happen either. We (Volvo) tried that before we bought Mack and the Intl. shareholders rallied together and drove the price up. I think they're SOL right now. It's a bit too late in the game to start playing at this point.

 

Cat/Navistar news...

Current Trucking Industry News: TruckingInfo.com : Your Source for Trucking Information and News

 

What they use is "filtered" exhaust gas AFTER the dpf. Great theory that causes packaging nightmares for chassis OEMs.

 

Cat paid non-compliance penalties for it's engines, and did not suffer backbreaking warranty claims in it's emissions engines regarding add-on emissions devices. They also were able to substantially reduce the penalties paid in the on-highway segment of their engine lineup by applying their ACERT technology to their ENTIRE engine lineup, of which the on-highway division was only 10-15%. We've all seen how older (pre-2000) off-highway Caterpillar engines were mobile smoke farms; ACERT reduced that by a huge degree.

The other OEM's used add-on emissions devices, and absorbed HUGE amounts of warranty claims for covering failures in said add-on emissions devices (incidentally not manufatured by the OEM's).

I wonder who "won" the money battle?

My money's on Cat.

Cat's ACERT technology met the ORIGINAL specs for 2004 emissions standards without the use of aftertreatment strategies. In the 2002 "Consent Decree", emissions targets were accelerated AND strengthened to "compensate" for all the "non-compliant" 1994-2000 engines -- thus the phase-in of EGR in 2002, versus 2004. The strengthened targets could only be "met" by supplemental aftertreatment in the exhaust stream (which incidentally, were only manufactured by two companies, neither of whom were engine manufacturers).

The two biggest parts of the ACERT strategy were:

1) Advanced combustion event management, facilitated by multiple injection events (as many as 5-6) in a combustion event. In a sense, they DID use exhaust gas to reduce combustion temps, but they did it by generating the exhaust gas in the cylinder, before the main combustion event. (As opposed to using complicated plumbing (VGT's and EGR coolers, and problematic valving) that was reverse engineered onto an existing platform.)

2) twin sequential turbo's, whose exact function I'm STILL not clear on.

The other OEMs' approach was to use the aforementioned plumbing, and as we all know from PSD experience, was beset from problems from the outset. The accelerated phase-in schedule resulted in the loss of over half the normal development mileage/time, and as such the problems had to be resolved at the customer's expense. I'm aware of multiple revisions to Detroit's Series-60 EGR cooler over it's 2002/4-2007 operational timeframe, as well as less-than-spectacular (and certainly less than advertised) lifetime on the EGR control valves.

Additionally, as far as I know, ALL the other OEM's had significant difficulties with sizing the EGR coolers (even in the PSD), which resulted in frequent de-rating of the engine to keep the undersized coolers from overheating. It's a pretty safe bet that any time you see a truck struggling to pull a grade, it's suffering from a derated engine (as much as 50%) while trying to keep "clean" exaust.

"Add-on" EGR systems were doomed to failure almost from the concept stage because they were added onto engines that ran too hot (to get acceptable power/mileage figures) to be effectively "cooled off" given then-curent design requirements. Underhood packaging requirements virtually guaranteed that they were never going to be able to be appropriately sized to do the job required. You'll notice something about the 2008 model Class-8 trucks that are designed for continuance into the 2010 emissions regime: they ALL have MASSIVE faces/noses, to hold the 40% upsized radiators required to deal with the cooling system overload from the EGR systems.

(I'm immensely impressed with Detroit's new DD-15 engine, which was designed from the ground up as an EGR engine, and will only require minimal (if any) modifications to accept Detroit's forthcoming SCR/Urea system. Turbo-compounding? Old, IMPRESSIVE technology! (Too bad it's only being offered in a foreign-built, FUGLY truck.))

Cat's ACERT system sidestepped ALL of the problems in the preceding 3 paragraphs, but at the expense of creating a couple of it's own (the aforementioned valve adjustments being but one).

Further refinement of the ACERT system is what is allowing Cat to continue on a better ultimate path to emissions reduction in it's off-highway engine market. As is now public knowledge, the alliance between Cat and Navistar should allow Navistar to captilize on that knowledge to remain with it's (IMHO better) non-SCR approach to the 2010 emissions standards. And Cat will make better money by licencing someone else's product than it would by spending mega-million$ to develop it's own product in a market that they've readily announced they simply have no desire to continue to pursue.

As an aside, I'll be interested to see how Paccar, Cat's biggest on-highway customer, will work towards the "vertical powertrain integration" already demonstrated by Daimler Heavy Duty (formerly Freightliner) with Detroit, Mack/Volvo using their own respecive in-house branded powertrains, and Navistar remaining in-house as well.

Here's another link to the Cat/navistar Alliance, from E-trucker:

Cat to exit highway engines, build truck with Navistar - eTrucker

-blaine

 

Great read Blaine, as usual.

Another down side to ACERT is the poor fuel economy in the C15 engines not to mention the complexity and virtual mechanics nightmare caused by this system.

Paccar, as you know, will be using the DAF engine and SCR for 2010. That makes Navistar the lone chassis OEM not to use SCR. For their sake, I hope their aerodynamics are good enough to offset the additional fuel consumption caused by massive EGR engines. I'm sure the CU ISX will be better off, and we intend to test their concept side-by-side with our own. Judging by early figures on our own engines, Cummins will have to perform a miracle.

 

I am unimpressed with the urea-based SCR system; the whole concept, actually. It's the first system in widespread use that REQUIRES user intervention to function. As such, I'm largely convinced that it may be "great" until the first user intervention is required, and then it's going to be an absolute NIGHTMARE. Freddy Krueger ain't gonna have NUTHIN' on the boondoggle that SCR will eventually become.

Use in passenger vehicles is completely different than use in commercial ones, and the first dispatcher/driver combo that starts generating customer service failures (due to improperly operating or completely non-functional equipment) is gonna leave the heap parked by the side of the road. My personal experience is that while SOME large fleets have in-place systems to force maintenance intervals, not all do, and almost NO small fleets have systems that FORCE the maintenance. To wit: Werner starts docking DISPATCHER pay, then DRIVER pay, when maintenance intervals are not kept. However, Swift, at least during my tenure there during 1999-2000, had no system to FORCE maintenance, and as such I knew of a number trucks that had not even had the oil CHECKED (much less changed) in 60,000 miles. (Mine was not one of them.) Given that even many large-fleet trucks can never see the inside of a company terminal during a standard service interval (15K miles) you can see how problematic this may become.

Passenger car SCR systems require "service" two or three times per year, at most, requiring only a gallon or two of urea to complete the service interval, a quantity (and size) that's quite manageable. Commercial SCR systems will require SCR tanks at least as large as a fuel tank, and the loss of 500+ pounds of tare weight will be significant to many players in the industry. And given that those tanks will have to be filled on a montly basis, it's going to be even more significant. I fail to see how selling one-gallon quantities of urea (as is being forecast) will make a significant difference to a driver whose urea tanks are considered "empty", to get him to a point to where the system will function again. You think a DRIVER will pay for a dozen gallons of urea to make his truck run? NOT! Think about the many small less-than-five-truck fleets out there; having myself driven for a thirty-truck fleet, that was infamous for docking driver pay for anything OTHER than fuel (including oil and minor road maintenance), you can rest assured that urea expenses will be forced back to the driver instead of the oil. *I* personally would not pay for that if I did not own the truck. (And would be hard-pressed to do so, even if I DID own the truck.)

I suspect that the losses in fuel economy will not be quite as bad as is forecast, and the money saved by not having to purchase urea, and service the urea equipment, will more than offset the increased cost of fuel. Observation has suggested that total cost-of-operation is considered less than the raw fuel economy numbers, and that operational costs are actually increased in order to chase down "better" fuel "economy" numbers. And I suspect that precision computer control will result in 20% better fuel economy than on engines of the same displacement class that were used 20-30 years ago. Fifteen liter engines did not appear with the introduction of EGR; they RE-appeared after the drive for fuel economy forced 12-liter engines to generate 450+ HP.

-blaine

 

Just to enlighten you on a few facts.

Commercial vehicle urea tanks will NOT be as large as fuel tanks. Our maximum tank size is 18 gallons with a range of 6000 miles between fills. Yes, the tank will need to be filled before normal service intervals. There is a consortium of OEMs that are working with major fuel stops to make available bulk fill as well as 2.5 gallon jugs for purchase OTC. I don't see it as an inconvenience any more than having to stop for fuel, or pee for that matter. My test drivers feel the same way. Urea SCR is much more efficient at converting NOx to N than anything else. Since OBDII is being forced upon us, both SCR and massive EGR systems will be subject to derate if something malfunctions. In most cases, the only thing that could happen to a SCR system is running low on AddBlue. However, if something were to happen to a massive EGR system, it won't be as easy to fix. Cooling packages for massive EGR systems will be more expensive to replace after hitting a deer also.

There are pros and cons to each system and we can blame the EPA for all of this.

 

Doesn't urea freeze at around 15 degrees fahrenheit? How will that issue be handled?
Are there any concerns with making urea a product readily available to the general public?

 

It's not the act of filling the tank that's the problem; it's PAYING FOR IT. Many drivers, for better or worse, cannot buy ANYTHING except fuel (even oil) on the company fuel card; thus they are forced to pay for these extra items OUT OF POCKET, and then submitting receipts for re-imbursement. Re-imbursement does not always happen. Been there, done that, unfortunately. Ask your test drivers how they'd feel if forced to pay for the urea OUT-OF-POCKET. I'd bet money that they'd change their attitude fairly quickly.

$5 to replace a burned out clearance light is one thing; LEGALLY I'm responsible for that light (whether I get repaid for it or not). $20+ for a bottle of urea that I'm NOT legally responsible for (i.e. not having urea won't make me fail a roadside DOT inspection), and then not getting paid back for it, and I'd be leaving the truck on the side of the road, walking to the bus stop with my duffel bag in hand.

Yeah, yeah, I hear all the pro-SCR people talking about how easy it is to do, and how they're gonna have the infrastructure in place to supply the industry, blah, blah blah... I've been around this industry long enough to know that it's gonna blow up in people's faces if those faces aren't located within 10 miles of a major truckstop on I-10, I-20, I-40, or I-80, or local P&D in a major metro area... Oh, wait, that's what they want, isn't it?

-blaine

 

Very interesting stuff.

 

The tanks will be heated by coolant and the supply line to the injector will be heated electrically. It takes more than 35 hours to freeze a 18 gallon tank of urea completely solid.