Alan M. Petrillo
Diesel engine manufacturers are developing engines that generate more horsepower (hp) from the same or smaller size units, all while running cleaner to reduce or remove emissions and to more efficiently provide the most power for vehicle operations.
Diesel Technology
Dave Drehobl, manager of specialty vehicle business for Cummins Inc., says the evolution of technology over the years has radically changed diesel engines used in fire apparatus. "The first emissions regulations dealt with smoke and then nitrogen oxides (NOx)," Drehobl notes. "But, these days unburned hydrocarbons, oxides of nitrogen, and particulates are at near-zero-emission output levels in diesel engines."
He says that in 2002 the industry was first introduced to exhaust gas recirculation (EGR), which lowered NOx levels. "Engines today continue to use cooled EGR," he observes. In 2007, the industry was introduced to the diesel particulate filter (DPF), Drehobl says, which brought on the need for both passive and active regeneration. Most recently in 2010, the industry added selective catalytic reduction (SCR) with diesel exhaust fluid (DEF) to its diesel engines.
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(1) Cummins offers the ISL-9 engine, compliant with EPA 2010 emission regulations, which features the XPI fuel system, enhanced cooled EGR, a single VGT turbocharger, selective catalytic reduction, and Cummins particulate filter. (Photo courtesy of Cummins.) |
"With greenhouse gas fuel efficiency regulations in front of us," Drehobl says, "what's happening now is the integration of onboard diagnostics (OBD) into engines, something that has been around since the late 1990s in cars and light trucks."
Cummins uses an engine control module (ECM) running OBD software in the background that monitors the engine in a real-time diagnostic mode to identify if there is any engine system malfunction, Drehobl says.
He points out that the Environmental Protection Agency (EPA) and the California Air Resources Board expect that an engine will remain in compliance with coming greenhouse gas regulations as it operates. "Our engine control module accomplishes that task as it performs diagnostics on the engine, aftertreatment, cooling system, and the charged air system on the vehicle," Drehobl adds.
Because diesel engine emissions have been reduced to near-zero levels, regulators are now focusing on improving fuel economy, and greenhouse gases and fuel economy work hand in hand. "Greenhouse gas rules regulate the carbon dioxide (CO2) output from the engine," Drehbol points out, "and when you lower carbon dioxide emissions, the engine consumes less fuel and the miles per gallon improve."
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(2) The ISX-12 engine made by Cummins was designed to deliver better fuel economy, performance reliability, and durability in a compact design that could save space on fire apparatus. (Photo courtesy of Cummins.) |
Durable with Less Weight
Creighton Pritzlaff, Navistar's vocational sales manager for the North American fire and emergency segment, says Navistar offers its own brand of engines in commercial chassis in a range that includes the Maxxforce-7, Maxxforce-11, and Maxxforce-13 engines. The Maxxforce-13 is available in a 475-hp rating (1,700 foot pounds of torque), two 450-hp ratings (1,700 foot pounds of output and multitorque output of 1,550/1,700 foot pounds), as well as a 430-hp r