John C. Hedrick

Exhaust Emissions From a 1,500 kW EMD 16-645-E Locomotive Diesel Engine Using Several Ultra-Low Sulfur Diesel Fuels

This paper documents results from an experimental study performed to determine the effects of several ultra-low sulfur diesel (ULSD) fuels (< 15 ppm S) on exhaust emissions from a 1,500 kW EMD 16-645-E, roots-blown, diesel locomotive engine. U.S. EPA-regulated emission levels of hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx ), and particulate (PM) were measured using U.S. EPA locomotive test procedures while operating on four ULSD fuels, plus a fifth baseline fuel which was a commercially-available Federal on-highway diesel fuel (< 500 ppm). The four ULSD fuels were (1) a ULSD California motor vehicle diesel fuel (CARB fuel) with an aromatic content of less than 10 percent, (2) a ULSD “equivalent” California motor vehicle diesel fuel with an aromatic content of 24 percent, (3 and 4) two custom blended “2006 ULSD Federal” diesel fuels with relatively low Cetane Numbers and higher aromatic levels. This paper reports the changes observed in the regulated exhaust emission levels between the ULSD CARB diesel fuels and the ULSD Federal diesel fuels.Copyright

Locomotive Idle and Start-Up Exhaust Emissions Testing

The objective of this project was to quantify locomotive idle and start-up emissions, to answer the question: “At what point is it preferable from an emissions standpoint to idle a locomotive engine rather than shut down the engine and restart it when needed?” Idle and restart emissions tests were performed on two Tier 0 emission locomotives; a 1,120 kW EMD MP15-DC Switcher (UPY1378) and a 3,280 kW line-haul GE Dash9-44CW (BNSF4373). The results of the testing showed that continuous idling emissions of NOx and PM were greater than the start up emissions from the two test locomotives. The only exception was the 15-minute restart on the line haul locomotive BNSF4373, but this was envisioned to be due to a non-typical operational cycle of the GE AESS. The results of the extended idle tests showed that the older locomotive (UPY1378) operates at a relatively consistent idle emissions output through the four hours of extended idle. However, idle emissions from BNSF4373 varied over the idle period as the engine speed changes in response to on-board computer controls to accomplish engine warm-up and a series of other locomotive functions.Copyright

Locomotive emissions measurements for various blends of biodiesel fuel.

The objective of this project was to assess the effects of various blends of biodiesel on locomotive engine exhaust emissions. The emission tests were conducted on two locomotive models, a Tier 2 EMD SD70ACe and a Tier 1 Plus GE Dash9-44CW, using two baseline fuels: (1) conventional Environmental Protection Agency (EPA) ASTM No. 2-D S15 certification diesel fuel and (2) commercially available California Air Resource Board (CARB) Ultra Low Sulfur Diesel (ULSD) fuel. A single batch of soy-based B100 was mixed in with the EPA and CARB diesel to yield a 5 percent and 20 percent blend of fuel. A randomized test matrix was used to perform triplicate tests on each of the six test fuels (EPA0, CARB0, EPA5, CARB5, EPA20, and CARB20). General emissions and fuel economy trends seen in other studies and applications for biodiesel use were also observed in this study. Higher blend levels of biodiesel were associated with lower carbon monoxide and particulate matter, as well as with higher levels of nitrogen oxides and fuel consumption. Use of diesel fuel with 20 percent biodiesel often resulted in statistically significant differences from the fuel with 0 percent or 5 percent biodiesel, while the difference between 0 percent and 5 percent biodiesel was generally not statistically significant.

An Accelerated Testing Approach for Lubricant Oil Consumption Reduction on an EMD 710 Diesel Engine

Real-Time Da Vinci Lubricant Oil Consumption (DALOC™) measurements were made on a 2,942 kW (4,000 hp) EMD 16-710G3 locomotive diesel engine, as part of a program to evaluate prototype cylinder kits that hold the potential to reduce lubricating oil consumption and hence reduce exhaust particulate matter emissions towards meeting EPA Tier 0+ locomotive emissions certification. The DALOC technique uses sulfur dioxide (SO2 ) measured in the exhaust gas stream as a tracer for oil consumption. The engine was operated on an ultra-low sulfur diesel fuel (3 ppm by weight) and commercially available SAE grade 20W40 mineral-based lubricating oil (4,865 ppm by weight). Knowing the SO2 concentration in the exhaust, the air and fuel flow rates, and the lubricating oil consumption rate can be calculated in real-time, i.e. on a second-to-second basis. Use of this measurement technique on the locomotive engine application has proven to be a cost- and time-reducing tool for mapping steady-state lubricating oil consumption rate. Numerous prior publications describe the evolution of this technique over time as well as the prior art in the area of lubricant impact on emissions [1–12]. As part of this project, the lubricant oil consumption of 4 different cylinder kits were accurately quantified at 4 steady-state operating conditions typical of North American freight locomotive operation within less than 40 hours of actual engine running. Applying this measurement technique, a reduction of lubricant oil consumption of 75%+ in comparison to the baseline cylinder kits were documented.Copyright

Partial Flow DPF System for Large Bore or High Power Applications

A number of technical challenges are faced when applying wall flow Diesel Particulate Filter (DPF) systems to large high horsepower off-highway applications, locomotives, and marine diesel engine applications due to the size of the DPF system required and the space constraints associated with these applications. Experimental results show that a new approach of adding an exhaust bypass valve, creating a partial-flow DPF system, can greatly reduce the DPF package size while continuing to offer significant PM emission reductions. The exhaust bypass valve is configured to open proportionally to maintain a pre-set maximum engine backpressure as the exhaust flow increases.Proof-of-concept testing of an experimental partial flow DPF system was conducted on a 3MW, 4-stroke locomotive engine, following U.S. EPA locomotive certification test protocols. These tests showed that the experimental DPF system, which was approximately 40 percent smaller than what would be expected for this application, provided an 84 percent PM reduction over the US-EPA Switcher Cycle and 59 percent reduction over the Line-Haul Cycle. It was calculated that the system could provide a 91 percent PM reduction over the Switcher Cycle and 76 percent PM reduction over the Line-Haul Cycle with addition of a DOC in the bypass exhaust flow.Copyright

Diesel Particulate Filter Retrofit of a 1500 kW Multi-Engine Genset Locomotive

This paper documents the initial test results of a locomotive diesel particulate filter (DPF) retrofit project. The locomotive used for this project was BNSF1284, a 1,566 kW National Railway Equipment Company (NREC) model 3GS21B, originally manufactured in April, 2008, and designed to be an Ultra-Low Emissions Locomotive (ULEL). This genset switcher locomotive uses three Cummins QSK19 Cummins 522 kW diesel-engine driven generator sets (Genset 1, 2, and 3) to provide the power needed to drive the traction motors.The GT Exhaust Diesel Particulate Filter (DPF) retrofit system, installed on BNSF1284, uses catalyzed DPF elements. The DPF, and its catalyzed coating, offered significant hydrocarbons (HC), carbon monoxide (CO), and particulate (PM) emissions reduction. Additionally, the catalyzed coating should allow the diesel particulate filters to passively regenerate at moderate exhaust temperatures, thus keeping the engine back pressure within allowable limits of the manufacture.The GT Exhaust DPF’s were installed in place of the standard mufflers on each of the three engines. The GT Exhaust DPF’s are roughly the same size as the stock muffler. The only locomotive modification needed to install the GT Exhaust DPF’s was to the muffler mounting platform, directly above the engine, where the exhaust pipe opening needed to be enlarged. There are no external modifications to the locomotive car body needed to install the GT Exhaust DPF’s.After installation of the DPF’s, they were degreened by operating the engines at rated power for 20 hours. After degreening testing was performed according to Title 40 of the U. S. Code of Federal Regulations (CFR), Part 92, Subpart B. The addition of the DPF reduced the PM emissions to 0.016 g/kW-hr or 60 percent below the locomotive Tier 4 PM limits.BNSF1284 was returned to revenue service in Richmond, California in March 2012, where the DPF performance will be tracked for 3,000 hours of operation as part of a California Air Resources Board (CARB) verification program.Copyright

Development of a Low Emissions Upgrade Kit for EMD GP20D and GP15D Locomotives

This paper describes the development of a low emissions upgrade kit for EMD GP20D and GP15D locomotives. These locomotives were originally manufactured in 2001, and met EPA Tier 1 locomotive emission regulations. The 1,491 kW (2,000 HP) EMD GP20D locomotives are powered by Caterpillar 3516B engines, and the 1,119 kW (1,500 HP) EMD GP15D locomotives are powered by Caterpillar 3512B engines. CIT Rail owns a fleet of 50 of these locomotives that are approaching their mid-life before first overhaul. Baseline exhaust emissions testing was followed by a low emissions retrofit development focusing on fuel injection timing, crankcase ventilation filtration, and application of a diesel oxidation catalyst (DOC), and then later a diesel particulate filter (DPF). The result was a EPA Tier 0+ certification of the low emissions upgrade kit, with emission levels below EPA Line-Haul Tier 3 NOx, and Tier 4 HC, CO, and PM levels.Copyright

Application of an Experimental EGR System to a Medium Speed EMD Marine Engine

This paper focuses on quantifying emission reductions associated with various on-engine technologies applied to Electro-Motive Diesel two-cycle diesel engines, which are very popular in marine and locomotive applications in North America. This paper investigates the benefits of using exhaust gas recirculation (EGR), separate circuit aftercooler, and retarded injection timing on a EMD 12-645E7 marine engine. The EGR system alone provided up to a 32.9% reduction in brake specific Nitrogen Oxides (NOx ) emissions while demonstrating less than one percent increase in cycle brake specific fuel consumption (BSFC). The brake specific particulate matter emissions increased somewhat, but at a modest rate based on the amount of NOx emission reduction. When the enhanced aftercooler system was combined with the addition of EGR, there was a 31.9% reduction in NOx and essentially no change to the BSFC when compared to the baseline test. The minimum manifold air temperature (MAT) was limited due to the size of the standard EMD aftercooler heat exchanger that is fitted on the engine. No efforts to modify the turbocharger to improve the turbo match to take advantage of the lower manifold air temperatures and the corresponding lower exhaust energy. Once 4° static injection timing retard was introduced, along with the EGR and the minimum MAT, a maximum NOx reduction of 49% was realized with only a 1.1% increase over the baseline BSFC.Copyright

NOx and Fuel Economy Challenges With EMD Two-Stroke Engines: Variable Injection and Valve Timing

NOx emissions are a major cause of ozone formation. Several technologies to mitigate NOx in internal combustion engines have been developed, both in-cylinder and aftertreatment. Some of these newer technologies are being implemented on new engines, but older engines, especially large diesel engines, have few options to reduce these emissions substantially. The most common method of NOx reduction is retarding the start of injection timing but this has a penalty in fuel economy. A program has been undertaken on an EMD 645E two-stroke diesel engine to combine a simple mechanical system with both retarded and variable start of injection — to mitigate NOx — with variable valve timing to offset the fuel economy penalty. Simulation modeling and on-engine experimentation have been carried out to quantify the extent of the NOx reduction with the impact on fuel economy.Copyright

Experimental Application of Diesel Particulate Filters to EMD Switcher Locomotives

The use of exhaust aftertreatment technologies may be required to meet the future Tier IV locomotive emissions standards that have been proposed by the US-EPA. Diesel Particulate Filters (DPF) can achieve a high level of particulate matter (PM) emissions reduction, and they are currently being used on all new 2007 on-highway diesel trucks in the United States. In addition, DPFs have been installed on lower power (1500 kW and less) locomotives in Switzerland that are fitted with 4-cycle high speed diesel engines. However, these systems are only now beginning to be sized and demonstrated in a locomotive environment in the United States. Initial testing of the retrofitted DPF system on a 1,125 kW two-stroke, EMD 12-645 Roots-Blown engine powered locomotive achieved an average 80% reduction in Particulate Matter and an average of 30% reduction in Hydrocarbon from the baseline emissions levels. This paper will discuss the background of the “California Emissions Program”, the current and recently proposed EPA emissions standards for locomotives, the Diesel Particulate Filter (DPF) used in the field demonstration, and emission test results.Copyright