- Published: Sunday, 01 August 2010 08:00
- Written by CP Staff
Concrete fleets approach a new era as engine and truck manufacturers clear 2009 inventory and modify mixers, dumps and product-hauling vehicles for power and exhaust treatment packages meeting Environmental Protection Agency diesel emissions thresholds effective January 2010. Producers will find higher price tags on new trucks, reflecting perhaps $7,000-$9,000 in premiums manufacturers attribute to EPA 2010 compliance. The agency's new threshold for diesel engine emissions is 0.2 gm/brake hp-hour and 0.01 gm/brake hp-hour for oxides of nitrogen (NOx) and particulate matter, respectively.
Those shopping new vehicles for the first time since the peak concrete-demand years of 2005-2007 will find a sharply different landscape, marked by truck model changes, brand sunsets, and evolution of engines and exhaust components beyond the diesel particulate filters central to EPA 2007 phase emissions compliance:
- Selective Catalytic Reduction (SCR) chambers treating post-diesel particulate filter (DPF) exhaust
- Urea or diesel exhaust fluid (DEF) tanks, charging SCR chambers
- Under-step mounting of DEF tanks (driver side) and DPF and/or SCR components (passenger side), or combinations of under cab and back of cab (passenger side) mounting
- Caterpillar Engine Division's exit from on-highway market
- Discontinuation of widely specified Cummins ISM engine in favor of the EPA 2010-compliant ISX11.9 and new ISL version
- Detroit Diesel's presence, via the DD13 engine, in mixer- and dump-grade power and torque categories
- Paccar Inc. offering its own MX engine for Kenworth and Peterbilt models
- Navistar Inc. differentiating its EPA 2010 compliance strategy through Advanced Exhaust Gas Recirculation (EGR), eliminating competitor-deployed SCR components and DEF tanks
- Freightliner addressing a Sterling brand void with its M2 and Concord models, in set-forward and set-back axle configurations
- Moderate fuel-economy improvements with EPA 2010 power compared to earlier generation engines (over-the-road trucking applications have seen 5 percent improved economy; equipment manufacturers see lower percentage for on/off-highway applications)
Shipment of EPA 2010-compliant heavy-duty diesel engines and exhaust treatment systems has reached critical mass, albeit in mainline, over-the-road trucking: Volvo Trucks North America and Daimler Trucks North America each reported earlier this summer they had reached the 10,000-order mark for vehicles built with mostly new 13- or 15-liter Volvo, Mack, Detroit Diesel or Cummins power and companion SCR packages. For mixers, dumps and other on/off-highway vehicles, the migration to 2010 power has been slower, but figures to step up this month as the Cummins ISX11.9 enters full production.
Among the handful of early EPA 2010 power adopters Concrete Products has identified are three Texas operators: Nelson Bros. Ready Mix in Lewisville, Texas, running a Mack MP7-powered Granite Axle Back; Kansas Ready Mix, Wichita, operating four Mack MP7-powered Granite Axle Forward bridge formula mixers; and, Cemex, which in late-July took delivery of a DD13-powered Freightliner M2 (above photo) for a key Houston plant.
MACK TRUCKS INC.
The MP engines feature the ClearTech SCR system, EPA 2010-certified and delivering near-zero emissions. Mack was the first heavy-duty truck and engine manufacturer to achieve agency compliance certification, notes Senior Vice President, Sale & Marketing Kevin Flaherty, adding, We had trucks in customer hands early and often for testing, and were ready to go soon enough to start production last fall.
Mack showed a working engine and exhaust solution for 2010 EPA compliance on a mixer and dump at the 2009 World of Concrete; at the 2010 event, it displayed two Granites with production engines and exhaust systems, bearing McNeilus and Beck Industrial mixers.
Mack's ClearTech diesel emissions control system uses SCR to reduce NOx output to near-zero, while at the same time improving fuel economy by up to 5 percent and reducing active regenerations of the diesel particulate filter. ClearTech injects diesel exhaust fluid (DEF) Û a nontoxic solution of ultrapure water and urea, a common nitrogen-bearing compound Û into the engine's exhaust stream. DEF works with the hot exhaust and a catalyst to convert NOx into nitrogen and water vapor, harmless and natural components.
Mack tested ClearTech in North American customer fleets for more than two years, tracking performance and fuel consumption through 5 million miles of field service.
DAIMLER TRUCKS NORTH AMERICA
The company is positioning its Freightliner brand for stronger presence in construction through the M2 model, picking up where the discontinued Sterling brand left off and replacing the Freightliner FL series. A new Coronado SD, especially suited for dumps, replaces the FLD. The M2 was introduced in 2009 with a set-back axle version, to be followed this fall by a set-forward axle version.
Freightliner showed an M2 set-back axle model with McNeilus mixer and Detroit Diesel DD13 engine at the 2010 World of Concrete. EPA 2010-compliant through the BlueTec SCR technology (charted below), the DD13 will bring Detroit Diesel into mainstream specifications for concrete fleets; limited ratings have made the brand an infrequent power source for mixers for at least two decades.
The 12.8-liter DD13 replaces the MBE4000 and features a six-cylinder, in-line configuration. It will be offered in output and torque variants from 350 to 470 hp and 1,250 to 1,650 lb-ft. Built to spend more time in top gear, the DD13 pulls strong down to 1,100 RPM, which results in increased fuel economy. Its enhanced cooling system reduces fan on-time, further contributing to the engine's fuel-efficient design. Another key feature is the engine's electronically controlled Amplified Common Rail Fuel System, a delivery component working with Detroit Diesel's DDEC VI management system to deliver the exact amount of fuel needed at just the right moment, creating an optimal combustion event.
The result is a more fuel-efficient engine, company engineers note, and a reduction in NOx emissions without draining power. The engine was designed with convenience in mind, they add, pointing to positioning of the cartridge-style filters (oil, coolant and fuel) above the frame rail, plus maintenance-free crankcase breather. The DD13's torque curve provides an extremely wide peak torque range, up to 500 rpm, allowing drivers to locate with ease the Îsweet spotÌ for optimum engine performance. In addition, an asymmetrical turbocharger results in fewer moving parts when compared to VGT or waste-gated turbocharger designs. Other key engine features contributing to the all-around performance of the DD13 include the Jacobs engine brake, which is integrated into the engine and offers up to 546 braking horsepower; a robust rear gear train; and a ribbed cast ironblock that lowers noise-vibration harshness.
International trucks, including the WorkStar 7600 and PayStar 5000 series, will meet 2010 EPA diesel engines emissions requirements with MaxxForce Advanced EGR (exhaust gas recirculation) engines. An emissions-reduction technique already used in most gasoline and diesel engines, EGR works by re-circulating a portion of an engine's exhaust back to the engine cylinders and burning off excess pollutants.
As temperatures in the combustion chamber get hot, oxides of nitrogen (NOx) form and, when combined with hydrocarbons, yield smog. EGR re-circulates this exhaust into the intake stream. Since the exhaust gases have already combusted, they don't burn again. These gases displace some of the normal intake, slowing and cooling the combustion process, which reduces NOx formation. The 2010 MaxxForce are engineered to precisely control the flow of recirculated exhaust. These engines have increased injection pressure, improved combustion and refined calibrations with that goal in mind. The result is an engine that treats NOx in-cylinder and, therefore, requires no extra exhaust treatment effort from truck operators.
Navistar underscores these technologies behind MaxxForce engine performance:
Advancements in fuel injection
Next-generation fuel injection systems are capable of delivering fuel into the cylinder multiple times per cycle and at higher pressures. Utilization of one or more pre- and post-injections along with the main injection event means combustion can take place over a longer period and be more complete, resulting in less creation of NOx emissions.
Improved air intake management
The advanced EGR system uses dual turbochargers. The first, smaller turbocharger spins up immediately to provide boost at lower engine speeds, while the second, larger turbo provides maximum power at higher engine rpms. The company also placed an inter-stage cooler between the turbochargers to help reduce air temperature going into the cylinders and allow more air to be packed into the large second-stage turbo for maximum power at high engine speeds.
Improved electronic calibration
Engine controllers previously used a preprogrammed lookup table to determine the fuel-air mixture to burn. Increases in computing power allow the engine controller to continuously calculate the optimum mix to achieve maximum power and efficiency in many different situations.
Proprietary combustion technology
The redesigned combustion bowl combines with the higher fuel injection pressure to break the fuel up into a finer mist that is spread more evenly inside the cylinder, resulting in a more complete and cleaner burn.
The ISX 11.9 is set to round out Cummins' 2010 heavy-duty engine line, with full production commencing this month on the heels of the model's Environmental Protection Agency and California Air Resources Board certification. A mixer- and dump-suited ISM successor, the ISX11.9 engine and its exhaust treatment components meet EPA January 2010 oxides of nitrogen (NOx) and particulate matter thresholds of 0.2 grams and 0.01 grams per brake-horsepower-hour, respectively.
Like the well-traveled ISX15, the new ISX11.9 uses an enhanced cooled Exhaust Gas Recirculation system, single VGT Turbocharger, and proprietary XPI fuel system. The latter is able to produce extremely high pressure independent of engine speed, enables controlled fuel injection events, and is instrumental in achieving up to 5 percent better fuel economy than a comparably rated ISM predecessor.
Both ISX engines attain EPA 2010 emissions compliance through the Cummins Aftertreatment System with Selective Catalytic Reduction technology. The ISX11.9 is offered in 310-450 hp and 1,150-1,650 lb-ft torque ratings, with optional features including single- and dual-cylinder air compressors; Front Engine Power Take-Off; and, an enhanced Rear Engine Power Take-Off for customers who need to maximize payload.
Production ramp up and agency certification follow a validation regimen that saw ISX11.9 test engines accumulate 1.4 million-plus miles and 19,000 hours of operation in nearly 20 unique vehicle installations. Equal to rigorous duty cycles, Cummins engineers contend, the new model features better pulling power and stronger clutch engagement than earlier-generation power.
Scheduled for production at a new Mississippi plant, the Paccar MX will be available on models most commonly ordered for mixer and dumps: the Kenworth T800 and W900 and Peterbilt 365 and 367. The 12.9-liter engine has a 380-hp to 485-hp range and torque outputs up to 1,750 lb-ft. Fuel efficiency, durability and lightweight design, Paccar notes, position the MX for vocational and over-the-road models. In addition to Paccar power, Peterbilt and Kenworth heavy-duty models will be available with the (above noted) Cummins ISX11.9.
The MX engine meets EPA 2010 diesel engine emission guidelines through SCR technology, which requires an additional treatment chamber, coupled with a small quantity of urea or diesel exhaust fluid, beyond the diesel particulate filter of EPA 2007 emissions solutions.
The construction-grade Kenworth T440 and T470 models, engineered as heavy Class 7 or light Class 8 vehicles, will be available with Paccar PX-8 or Cummins ISL9, in 260-380 hp ratings, both meeting EPA 2010 emissions compliance with exhaust configurations mirroring the MX and ISX11.9. Peterbilt reported delivery of its first Paccar MX-powered model, a 386, in June.
NAVISTAR: EPA, CARB REEXAMINE
2010 SCR ENGINE CERTIFICATION
In a mid-July workshop, the Environmental Protection Agency and California Air Resources Board presented preliminary proposals aimed at reported compliance loopholes found in current 2010 liquid-based Selective Catalytic Reduction systems. Navistar first identified these loopholes to the agencies and also presented our concerns, said Navistar North American Truck Group President Jack Allen. We will be working with the EPA and CARB to ensure full environmental compliance.
Concerns about environmental compliance were backed up by what Navistar notes are independent test findings that show new commercial vehicles depending on liquid urea to meet federal oxides of nitrogen (NOx) emissions standards continue to operate effectively when urea is not present. At such times, Navistar contends, the vehicles throw off NOx as much as 10 times higher or more than when urea is present.
The test findings reflect research conducted by EnSIGHT, an independent environmental consulting firm, using two long-haul vehicles and one heavy-duty pickup, all of which use SCR technology that relies on liquid urea to clean up NOx emissions after they leave the engine. EnSIGHT's research showed that when liquid urea was not present, there was little or no effect on the vehicles' operations. This included long periods of time when the vehicles' urea tanks were empty or were refilled with water instead of urea. One truck tested appears to operate indefinitely with water and as a result without any functioning SCR NOx control. That truck has accumulated more than 13,000 miles with its SCR NOx emission control turned off.
European research also has shown that even with a full tank of liquid urea, Navistar reports, the SCR NOx emission-control system does not turn on when exhaust temperatures are not hot enough. This occurs during stop-and-go traffic. That means that there is frequently no SCR NOx control when these trucks are operating in urban areas, as well as in any other congested traffic situation.
Navistar, which commissioned EnSIGHT's work, joined two prominent environmental groups, the Coalition for Clean Air and Environment Now, in calling on the EPA and California Air Resources Board to eliminate the loopholes and the resulting excessive NOx emissions.
TEREX ISX11.9-POWERED FRONT: CHARGING INTO CONCRETEWORKS
Terex Roadbuilding reports that as of mid-summer, design and integration of the Cummins ISX11.9 in the FD4000 front-discharge mixer is nearly complete. A prototype was in final stages of engineering and has passed air and cooling tests, while initial unit orders have been placed and scheduled for fall 2010 delivery. A production ISX11.9 will replace a factory prototype engine on a demonstration front-discharge mixer scheduled to begin circulating customer plants in late summer or early fall, stopping in Charlotte, N.C., October 5-7, for the National Mixer Driver Championship and NRMCA ConcreteWorks Expo.