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From Dave 4/6/09:  I was talking with some folks from a large government agency here.  They (government agency) buy the new EXCESSIVE EGR trucks from the only one who makes them (medium duty trucks).  The Nav reps took the prospective future drivers of those EXCESSIVE EGR trucks to a TRAINING, in which they explain all the gizmos of their system.

First thing that made the "future drivers" drop their jaws to the ground is the price of the DIESEL PARTICULATE FILTER and the Expensive Material Coolers.  Second issue -- drivers will be responsible for any malfunction or mis-operation of the system which will void the warranty.  Third issue -- some warranty issues.  Fourth issue -- they were trained to watch out for more REGEN events and look out for the DPF replacement periods.  (The more REGEN events, the more DPF replacement periods.)


No fuel economy talk on their training.

Those drivers told me that they will continue to drive the older trucks and the new ones will sit at their local yards.  And they say ADVANCED EGR is hassle free!!!


A:  Dave...I believe you've struck pay dirt here!

Can I use the term "Excessive" EGR?  It actually is much more descriptive than "Massive" EGR.  If you ever decide to leave the employ of Uncle Sam, call me first!

Anyway, you are correct there are a lot of new "gizmos" for 2010 regardless of technology selection.  The most onerous one is OBD, aka On-Board-Diagnostics.  This is the device that monitors ALL ASPECTS of engine performance and outputs.  Oh yeah -- it records all of this data too.  The good news here is that in 2010, Mack will use our Co-Pilot driver information center to alert the driver/operator of any out of EPA compliance issues.  The display can be toggled from English, Spanish, French and Russian Cryllic(?).

All DPFs are loaded with precious metals and they can be expensive.  The good news here is that very rarely do you have to actually replace the DPF.  Something around 200 to 300,000 miles, the DPF will have to be cleaned and reinstalled.  This should be around a few hundred bucks every few years.  If the DPF is damaged, either physically or with sulfur poisoning, then it will have to be replaced.  That would be big bucks.  One activity that will shorten the life of the DPF is heat cycling or the amount of active regen events over time.  With SCR, we drastically reduce active regen's to ZERO for the highway and NEAR ZERO for vocational trucks.  Excessive EGR active regen's will be significantly increased -- thereby shortening the life expectancy of the DPF.  Now that's expensive.

On the fuel economy side, there was no talk because there isn't anything to talk about.  It is poor; just ask Clessie Cummins, they threw in the Excessive EGR towel last August.  Just think about the amount of time, effort and money spent there, only to do a 180 and go with SCR.  Simple -- it's the fuel economy -- period.  Make no mistake.  Our own FE data from customer field test trucks has been excellent!  It's nice to have something to smile about these days.

I wouldn't be afraid of 2010 technology regardless of the system used.  We have taken our time and the safeguards for driver alerts are clear and in place now.  Thanks for your information!

From Fabian 4/4/09:  Hello, I am from Puerto Rico.  Can all those in the industry that embrace the SCR technology (all the major diesel engine/truck manufacturers) go to the local politics (Congress) to see if we get a DEF incentive tax credit just as propane does.

I think this will help a lot.  Propane fuel users get a 50 cent tax credit for every gallon of propane they use.


Maybe we can get a 50 cent tax credit for every DEF gallon we consume.  Think about this one.

A: interesting point of view here and I do like your way of thinking!  To date, I have not heard of any concerted effort focused for tax relief on DEF.  I will contact our Washington folks and see where we stand on some sort of DEF credit.  So far we have managed to stave off attempts to tax DEF at the Federal level -- which I accept as a small victory.

I've never been to Puerto Rico, Fabian, although Scotty B (who works for me, I think?) has been there on dealer visits a couple of times.  Strangely, this always seems to be in the dead of (an Allentown) winter, whilst your humble SCR guy here finds himeself sledding off to Winnipeg in Canada, where by comparison, Allentown is downright balmy!

One of these days....

 From Jim 4/1/09:  Dave, I came across an alarming article on Urea (DEF) that states that DEF deteriorates at higher than 86 degrees.  My trucks run in ambient air temperatures that are above 86 degrees.  Will the deteriorated DEF poison the SCR or Ammonia Slip Catalysis?

I read your responses, I gain confidence in SCR, but then I receive articles like this and my confidence in SCR starts to move towards the fence.


Can I drain the DEF out and put new in, if I was to purchase an SCR vehicle?  How do I handle the temperature issue?

To answer your question 'who we are'... my technicians and fleet managers keep sending me articles like the one I read.  I am not sure what their deal is but there doesn't seem to be many articles stating the benefits or problems with EGR. 

A:  Jim -- always interesting stuff you manage to find.

"Alarming" is a word I would use if one of your technicians were to drink some Diesel Exhaust Fluid.  Certainly not an adjective one should use when handling and storing DEF.  Windshield washer fluid is significantly more toxic than DEF, not to mention diesel fuel, engine oil, synthetic gear lube, antifreeze, battery acid, auto trans fluid, parts cleaners and so on.  We seem to have managed the handling of these materials safely for approximately 100 years.

You (or the article) fail to mention under what circumstances the DEF "degrades".  We have had a total of ZERO complaints and issues with the customer storage and dispensing of DEF after four complete seasons.  That is ZERO -- zip -- nada.  This includes use in high temperature and high humidity areas.  We check the DEF quality continually using a refractometer and have not noticed any measurable degradation through any temperature variable, not one whatsoever.  Now I must admit here in all honesty, our customers did store the DEF as required, not in an open container in the middle of the parking lot or inside their walk-in freezers.  It's the same treatment used for their lube oils and windshield washer fluids.

Jim -- get away from the fence!  SCR is here to stay.  Massive EGR is the last gasp (literally) and final EGR-only solution for EPA 2010 -- and remember clean air credits are burned to achieve this at an "alarming" rate.  No credits -- no can do.  Credits cannot be built up after December 31, 2009 so it is a constant and rapid depletion of the bank.

At the bottom of each DEF there is a small drain that is used for service purposes.

And as to who "we" are -- this is an offer from me to you, to meet with you, your drivers and your technicians and put these issues to rest, once and for all.

From Ken 3/30/09:  David, at the Mid America Truck Show, Volvo was talking about the future of active regneration events on its 2010 engines.  The need to NOT have to wait for REGEN or initiate REGEN.  It will be automatic, invisible to the customer.  Since Volvo has made this statement, customers have been inquiring as to what is Mack's position, especially in the vocational markets, local haul, ???  Since Volvo made these statements and also utilized the VHD for vocational/construction, maybe you can give me some added info on where Mack will be with 2010 REGEN's.

  Ken...thanks for the timely question.  Good one, too, as there is some confusion on active regen events today and going forward.

Since I wasn't invited to the VTNA MATS soiree, I had to read of their Zero Regen's for 2010 in a press release.  Maybe I should put my Uncle Ed Saxman back on the Christmas card list...


Anyway, onto what I know best -- Mack trucks.

Easily the most difficult transition to EPA 2007 was what we call the driver/operator interface, which is a fancy way of saying what the driver/operator sees, responds to and takes action on -- any alert or information signal.  Today when the system requests an active DPF regneration event to oxidize collected exhaust soot, we illuminate the upper part of the dash-mounted DPF Smart Switch.  This has caused some confusion with drivers as historically, we have schooled drivers that a yellow lamp was some type of caution indicator.  So each time this system demand lamp lights up, drivers always want to take some type of action -- leading to some confusion when there is nothing wrong -- just keep driving and it will go out in 2 minutes.  For 2010 we will eliminate this information only lamp, so even when an active regen event is demanded there will be no indication to the driver.  And these events will be very few and far between.

Mack trucks and "Near Zero" active regeneration events:  in several of our customer field test units, there have been no -- read ZERO -- active regneration events in over 40,000 miles of highway use.  These chassis all now have Production intent software, so what we are seeing today is what our customers will experience in a few months from now.  These chassis have a lot more than 40K miles, but that is when we installed the new s/w.  So for our highway customers, I feel very confident in stating their active regneration events are over!  Just think of the fuel savings from this alone!  Each moving active regen event consumes about a gallon to a gallon and a half of diesel fuel.  A forced - parked regen can consume up to 4 gallons.  This can and does add up.  So while the MEGR folks will definitely increase DPF active event frequency and duration, we will do exactly the opposite.

Mack vocational chassis will truly have "Near Zero" active regen events.  As the duty cycles of chassis in these applications vary, I'm very hesitant to claim zero, as that is a very definitive number, read -- ZIP!  Low vehicle/engine speeds in cold weather will contribute to the need for active DPF regen events even in 2010.  Where we are seeing something around every 8 to 13 engine hours today, that number will reduce to less than 5% of that frequency or just once every 3 months.  Several vocational field test chassis have not yet had an active regen event with 10,000 miles on the new s/w.  So I'm going to stick with near zero, because when 90% of our vocational customers experience no active regen events at all, we will have exceeded their performance expectations.

Rather wordy, but I hope this, ahem, clears the air.

  From Milton 3/26/09:  How will an "advanced" EGR engine perform at long time periods of PTO systems working "full throttle"?  Let's take the example of a concrete mixer.  PTO system operating at peak, truck is standing still.  I think excessive EGR engines will have some issues at this operating condition because with the truck not moving at all, no cool air flow will help the radiator or cooling systems of "advanced EGR" engines.  Please elaborate.  Is this a good question?

  Milton...a very good question you've asked here.  This area is so important for any low speed -- high torque = vocational applications.  Transit mixers and refuse collection vehicles, just to name two.


Although I do take issue with the term "advanced EGR" as there is nothing advanced about recycling up to ~50% of exhaust gas.

Operating an engine around the peak torque range creates the most heat -- read NOx -- in the entire duty cycle.  Generally, this occurs as the engine RPM reduces from cruise speed down to peak torque when a grade or headwind is experienced.  The key here is the truck is still moving through the air and at road speed.  Unfortunately, this does not occur in a transit mixer duty cycle under typical low speed vehicle operation.  Running the engine at "full throttle" at low vehicle speeds will alleviate some heat load issues -- but think of the fuel burned!

A 10 yard mixer barrel of low slump concrete requires ~170 HP just to drive the hydraulic system to the agitator speed, couple that with moving the vehicle through a job site of soft earth (sand if you are in Florida), which generates a significant amount of heat that must be managed.  A difficult task under these duty cycle circumstances; add power steering, air conditioning and an automatic transmission, you have a physical challenge.  A lot of heat, not much flow through air and low cooling fan speeds.

The Massive EGR folks announced for the first time during the recent NTEA Show in Chicago (of all places!) that they'll use a larger (+23%) cooling system coupled with a 4" raised hood and a 4" raised cab to accommodate.  So they already know heat is a significant problem with a non-SCR engine.

Reminds me of the time when I asked my boss for a raise...he told me to sit on a New York City phone book.  I sat higher but was no wealthier.  Go figure...

With Mack SCR, we will reduce the rate of EGR, thereby reducing the amount of rejected heat the engine produces.  We will keep today's cooling system going forward, drastically improving low speed cooling performance.

We now have a larger number of EPA '10 test trucks in vocational customer service and we are seeing ZERO heat load issues.  Another surprise is the amount of DEF we consume -- substantially below the 3% we have been talking about so far, another pleasant surprise there!

Between improved fuel economy, better thermal management and reduced DEF consumption, we are onto something here!

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