Diesel Engine Emissions A New Frontier In Preventive Maintenance

When 2007 rolled around and the EPA increased their emission standards everybody was waiting on what the original equipment manufacturers were going to do.

The diesel engine has always evolved through the decades but the challenge in the new millennium was to reduce soot and ash discharge levels out the tail pipe.

The catalytic muffler was the first on the scene along with ultra low sulfur diesel and low ash engine oil. The muffler transformed into the DPF diesel particulate filter which traps soot and then through an oxidation process remove harmful particulates from entering the atmosphere.

The very difficult problem for the engineers and the battle to stay within EPA specifications is costing Cummins, Mercedes and Navistar a lot of money in research and development. The progression to cooled exhaust gas recirculation worked for many years along with the DPF technology.

However the EGR by itself wasn't enough to keep up with environmental demands. Navistar this year will no longer supply diesel engines in the medium duty market. The EGR pictured above is out of a MaxxForce DT diesel engine. We have several of these engines in out fleet and this component needs regular maintenance or replacement at least once a year.

At the vary least removal and cleaning of the soot and ash buildup is necessary or the shaft that opens and closes the valve sticks and eventually causes the EGR valve to stay open which creates problems with power and take off ability. Every one of our fleet buses are checked for stuck EGR valves especially the older units.

Mercedes EGR valves have the same problem and eventually the electric motor that opens and closes the valve mechanism does not have enough strength to over come the soot covered shaft and valve assembly. At the end of this year Navistar medium duty diesel engines like the MaxxForce DT and MaxxForce 7 will not be manufactured any more.

The Cummins ISB will be taking over the field with it's own technology including the SCR (selective catalytic reduction) system that uses DEF diesel exhaust fluid to reduce emissions. They also have the VGT variable geometry turbocharger to increased heat to assist in the regen process that cooks out the soot build up in the emission system.

It's a heavy duty challenge to keep up with emission demands but when the going gets tough Cummins diesel engines get going. They have really excelled over other diesel engine manufacturers and went outside the box to over come the high demands from the EPA to reduce emissions levels to zero through out the transportation industry.  

MaxxForce Advanced EGR Has Arrived

International Corporation took a different approach to 2010 emissions. They went away from the UREA liquid process that other engine manufacturers are using. The video will give you an overview on how their new EGR technology works.

MaxxForce Advanced EGR has no equipment to add allowing extra payload capacity (and no body mounting issues). It does not require any liquid urea which cuts costs and extra stops to fill-up.

For 2010 the EPA requires diesel exhaust emissions to be reduced by 98%. The environment is on a lot of people's minds right now and the clean air movement is not going to slow down. It caught other engine manufacturers off guard so they fell back on liquid urea SCR, a technology that requires you to add after-treatment equipment and regularly fill up with liquid urea. International® took a simpler approach, perfecting its proprietary Advanced EGR system.



MaxxForce Advanced EGR reduces emissions internally with their diesel engines. It simply recirculates part of an engine's exhaust back to the cylinders, slowing and cooling the combustion process and burning off pollutants. MaxxForce Advanced EGR achieves greatly reduced emissions through a combination of increased injection pressure, improved exhaust flow and refined calibrations–and absolutely zero extra effort from the truck and fleet owner.

As a fleet Mechanic it's refreshing to know all we have to do is get in and drive. The add on equipment with SCR system sounds like an afterthought, like there was no time to change the engine design so UREA was the logical solution. This technology treats the exhaust after the engine 4 cycle process so there is a notable difference in the 2 systems.

Only time will tell which design will gain more popularity. I have to commend the engine manufacturers who bit the bullet and are still striving to meet the extremely strict emission standards put forth by the environmental watchdogs.