Motor Trends
Taking the Next Generation of Diesel Engines to Heart
 If our editors ran on diesel power plants, we’d get even more accomplished. Take a skid steer for instance, utilizing a fiery diesel engine. It can work 12-hour shifts, seven days a week, enduring dust and drastic climate change and still last for decades with the proper care. Is that so much to ask from fellow CE staffers?
I’ve been eyeing a liquid-cooled, four-cylinder, 49-hp diesel engine for myself — variable geometry turbocharger, Interim Tier 4 certified, in a nice compact package. I figure I can fix that power plant to a few hydraulic pumps that can power bionic limbs and a motherboard, doubling my output and intimating assistant editors with my Kung-Fu grip.
While this bold project has been put on hold (my publisher cites high fuel costs, although I suspect it goes deeper than that), we here at Compact Equipment have been totally engrossed in engines — especially with Interim Tier 4 emissions standards falling into place.
Over the last decade, the Environmental Protection Agency (EPA) has mandated that engine manufacturers (from Cummins to Detroit Diesel) engineer cleaner burning motors. These next gen off-highway diesel engines eliminate hazardous pollutants such as particulate matter (PM) and oxides of nitrogen (NOx), and manufacturers are also taking the opportunity to tweak their diesel designs, increasing efficiency and power for the end-user.
These new power plants will not only need to be cleaner, but also more fuel-efficient.
“With our Tier 3 engine technologies — cooled exhaust gas recirculation, variable geometry turbochargers, four-valve cylinder heads, air-to-air after-cooling, high-pressure fuel systems — companies like John Deere were able to achieve record fuel economy gains over our Tier 2 models,” explains Doug Laudick, product manager at John Deere Power Systems. “Interim Tier 4 engines will continue to use these same technologies and maintain similar fuel-economy leadership.”
 Fuel economy is just one of the pivotal issues surrounding Tier emission standards for the next generation of diesel engines. One of the most interesting and controversial arguments is between selective catalytic reduction (SCR) and cooled exhaust gas recirculation (EGR). Both technologies use different philosophies to meet new emission regulations. SCR is a European technology that uses a urea-based solution to reduce NOx. SCR advocates promote best in fuel economy with their new clean-burning power plants.
But most North American companies seem to be turning to EGR strategies, which lowers an engine’s peak combustion temperature to lower NOx output. The EGR camp says that SCR requires additional components and is overly-complex; also, urea may not be widely available in the Tier time frame.
Turn to the cover story on page 14 to delve into all the issues surrounding Tier 4 emission regulations. As these diesel engines continue to evolve, whether in compact machinery or cyborg journalism, Compact Equipment will be there to cover it.
Keith Gribbins
Managing Editor
kgribbins@benjaminmedia.com
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