FILL ‘ER UP—2X
I enjoyed reading the article about SCR and the new diesel engines. The benefits of SCR are quite interesting. I’m curious though as to what the conditions or parameters are for the engines using this technology to “run cooler” as you state early on? Because an aspect of adopting SCR is to allow for higher combustion temperatures – which reduces the amount of particulates but then results in more NOx being produced – which can then be treated away with the SCR system. So it seems that the engines would be generating more heat.
The reason SCR engines run cooler is because they recirculate much less hot exhaust gas into the combustion chamber than 2007-2009 EGR engines. EGR designs used exhaust gas because its oxygen content was low and that helped slow down the combustion for a more even and complete burn, but force feeding 1,000-degree plus air through your cylinders all day was hard on the whole system. It was only a stop-gap measure until the OEMs could figure out how to make the SCR systems work and the industry had time to get infrastructure in place to sell it.
You are right the in-cylinder combustion temps are higher in an SCR system, but only slightly so. The exhaust is also dirtier when it exits the exhaust valve, but filters and SCR clean that up nicely. On the heavy trucks all the OEMs except International chose SCR over increased EGR to meet the 2010 emissions regs. And Navistar/International only gets to keep EGR for the time being because they’ve got emissions credits from the EPA that the other’s don’t. Mack, Volvo and all the rest are able to cut their EGR rates and run cooler with SCR.
NEXT GEN PICKUP OWNERS
I just wanted to share a couple of pictures and a short story on how they came about. Last weekend the wife and I took our granddaughter (Lorelai) shopping with us. While we were in town we stopped so I could get a haircut. Once inside, Lorelai walked over to a table where some magazines were laid out and picked up a magazine then climbed up on the couch sat back and started turning pages. The other people there starting giggling and saying look at her. She was sitting there looking at your magazine turning page by page as if she was reading each page. I snapped a couple of pictures with my cell phone. My son and I own diesel pickups and my son is a technician for a Cat dealer, so she has been around trucks all her life. She is 2-1/2 years old and I guess you can say she is a real daddy’s girl! Just sharing a moment.
Lake Park, GA
STARK RAVING FAN
Not sure how you all do it, but this is the best and best written magazine for contractors and fleet managers. Be sure to pass this comment along to the staff because I can surely tell a lot of hard work went into this publication. Considering the number of these trucks and the lack of coverage of pickups in the Class 8 publications, I hope this works out well for you.
I personally like the style where there are three separate articles on the trucks rather than working so hard on a “comparison.” We all have our favorites, and we buy because of the dealership, etc., so in the end, we don’t always buy the “best one.” Hopefully the manufacturers appreciated this presentation as well.
The article on trailer pulling was especially informative. In the post-CARB world we continually eyeball the diesel pickup / dually specs to see if one of these trucks can come close to a medium-duty truck for our work assignments—a work crew, lots of hand tools, and hauling supplies to a jobsite. Maybe in a future issue you could mention fifth wheel goosenecks, trailer brakes, electric brake controllers and on-board batteries to activate brakes when detached and their charging systems.
Avila Beach, CA
Thanks for your comments. All the subjects you mentioned will be covered in future issues of ProPickup. In fact we’ve got a headache rack installation article in the next issue.
HYDRAULIC VS. ELECTRIC WINCHES
The comments by MileMarker (“Winches & Winching,” Spring 2010) were not totally correct. Most recovery’s are quick and short pulls, however it misleads customers to think that a MileMarker Hydraulic is the answer for heavy duty applications. The Dodge Power Wagon choose WARN over the MileMarker Hydraulic, in a day-long test at the Chrysler Detroit test facility, the electric winch outperformed the MileMarker two speed hydraulic in all the obstacles, without a battery change or allowing the truck batteries to fully recover. Today’s charging systems are much better than in the past and work best in most applications with electric winches. If you are moving into truly industrial applications such as tow trucks, fire trucks or hoist applications a hydraulic winch does have a place, however they require a reservoir that is large enough to allow the oil to circulate and cool keeping performance at its best.
Comments, criticism, praise?
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E-mail: [email protected].
Snail mail: Bruce Smith, ProPickup,
3200 Rice Mine Road NE, Tuscaloosa, AL 35406.