This study compared diesel exhaust emission for a low sulfur and a Fischer-Tropsch (F-T) diesel fuel. The comparison included regulated emissions, airtoxics, aldehydes/ketones, and greenhouse gas emissions. Testing was conducted using a Cummins B-Series engine installed in a heavy light-duty truck operating on a chassis dynamometer and on an engine dynamometer. The chassis driving cycles included city, highway, and aggressive driving operation. Engine dynamometer tests included the U.S. transient cycle. Results showed that the F-T diesel fuel substantially reduced emissions although the engine was not specifically tuned to take advantage of the unique characteristics of F-T diesel fuel.

Combustion models, used in spark-ignition engine modeling, are reviewed. Different approaches for representing the main combustion features are reported. Limitations in simulating such a complex phenomenon as turbulent combustion in engines are highlighted as well. In order to compare different combustion models, the multidimensional program KIVA-3V has been used. The behavior of an actual spark-ignition engine has been investigated. In particular, simulation results, using simple chemical kinetics and mixing-controlled models, are compared. The results obtained, compared to measured data, confirm that different combustion models can lead to a satisfactory prediction of engine performances. But, in many cases, these models require experimental data for determining the model characteristic constants. A hybrid combustion model is proposed. It is able to provide a good reproduction of engine combustion process and, in particular, the model seems to be less sensitive to the engine operation. The computation results are compared to the measured data.

Ultra-fast emission measurements can provide important information about the combustion system of an engine, especially during its development phase. The ability to measure NOx as soon as it exits the cylinder provides an insight to engine designers and combustion engineers about the in-cylinder process with regards to formation of NOx emissions. There are mainly two areas where such information can be used. First, the fast measurements can be used for the tuning of CFD models that are used during the development phase of an engine. Secondly, such a method could be useful in the first phases of engine testing during the development of the combustion system where engine tuning could lead to an overall superior compromise between an engine’s fuel economy and emission behaviour. The current research work investigated the potential of performing ultra-fast emission measurements in the exhaust port, immediately downstream of the exhaust valve, of a specified engine cylinder of a two-stroke large engine. A methodology was therefore developed and tested, by which emission measurements with fast temporal response can be conducted for individual engine cylinders. More specifically, an ultra-fast NOx measurement sampling probe was designed and developed to be applied mainly to 2-stroke engines, with the flexibility to also be applicable to 4-stroke engines. The development of the sampling system was done by initially performing NO measurements on the 4-stroke MAN L16/24 research engine, installed at the test bed of the Laboratory of Marine Engineering (LME), at the National Technical University of Athens (NTUA). Once developed, the final fast sampling system was then used for measurements of NO at the exhaust port of the 2-stroke MAN 4T50ME-X engine, at the MAN Diesel & Turbo test-centre in Copenhagen. The employed NO emissions measurement method provided the results on a cycle-by-cycle basis, and also as phase averaged values. The extremely fast response time of the instrument captured important details of the NO concentration in the exhaust gases, as soon as they exit the cylinder.

Pipeline natural gas composition is monitored and controlled in order to deliver high quality, relatively consistent gas quality in terms of heating value and detonation characteristics to end users. The consistency of this fuel means gas-fired engines designed for electrical power generation (EPG) applications can be highly optimized. As new sources of high quality natural gas are found, the demand for these engines is growing. At the same time there is also an increasing need for EPG engines that can handle fuels that have wide swings in composition over a relatively short period of time. The application presented in this paper is an engine paired with an anaerobic digester that accepts an unpredictable and varying feedstock. As is typical in biogas applications, there are exhaust stream contaminants that preclude the use of an oxygen or NO x sensor for emissions feedback control. The difficulty with such a scenario is the ability to hold a given exhaust gas emission level as the fuel composition varies. One challenge is the design of the combustion system hardware. This design effort includes the proper selection of compression ratio, valve events, ignition timing, turbomachinery, etc. Often times simulation tools, such as a crank-angle resolved engine model, are used in the development of such systems in order to predict performance and reduce development time and hardware testing. The second challenge is the control system and how to implement a robust control capable of optimizing engine performance while maintaining emissions compliance. Currently there are limited options for an OEM control system capable of dealing with fuels that have wide swings in composition. Often times the solution for the engine packager is to adopt an aftermarket control system and apply this in place of the control system delivered on the engine. The disadvantage to this approach is that the aftermarket controller is not calibrated and so the packager is faced with the task of developing an entire engine calibration at a customer site. The controller must function well enough that it will run reliably during plant start-up and then eventually prove capable of holding emissions under typical operating conditions. This paper will describe the novel use of a crank-angle resolved four-stroke engine cycle model to develop an initial set of calibration values for an aftermarket control system. The paper will describe the plant operation, implementation of the aftermarket controller, the model-based calibration methodology and the commissioning of the engine.

In order to investigate the possible environmental and economic benefits of lubricants optimized for stationary natural gas engine efficiency, a decision was made to develop a test stand to quantify the effects of lubricant viscosities and formulations on the brake specific fuel consumption. Many fuel economy tests already exist for evaluating gasoline and heavy duty diesel motor oils which have proven the benefit of fuel economy from different lubricant formulations. These engines would not be suitable tools for evaluating the fuel economy performance of lubricating oils formulated specifically for stationary natural gas engines, since there are significant differences in operating conditions, fuel type, and oil formulations. This paper describes the adaptation of a Waukesha VSG F11 GSID as a tool to evaluate fuel consumption performance. The performance of brake specific fuel consumption when using different formulations was measured at selected high loads and rated speed. The results of the testing program discuss the viscosity and additive effects of stationary natural gas engine oil formulations on brake specific fuel consumption. The results will detail the change in brake specific fuel consumption between natural gas engine oil formulations blended to varying viscosities and compared to a typical natural gas engine oil formulation with a viscosity of 13.8 cSt @ 100°C. The second portion of the test program explores the effect of different additive packages that were blended to the same finished oil viscosity. It was acknowledged that there were statistical differences in brake specific fuel consumption characteristics between lubricants different in viscosity and additive formulations.

As part of the U.S. Maritime Administration (MARAD) marine application of alternative fuel initiative, the U.S. Navy provided neat hydrotreated renewable diesel (HRD), derived from the hydroprocessing of algal oils, for operational and exhaust emission testing onboard the T/S STATE OF MICHIGAN. This vessel has diesel-electric propulsion with four caterpillar D-398 compression ignition engines; one of these ship service diesel engines was selected as the test engine. The diesel generator sets power both the propulsion motors propelling the ship and provide the electrical power for the hotel loads of the ship. Ultra-low sulfur diesel (ULSD) was blended with the neat HRD fuel in a 50/50-by-volume blend and tested for over 440 hours on the vessel. Exhaust emissions testing was performed while underway on Lake Michigan using the baseline ULSD assessed earlier. A similar profile was run using the blended test fuel. Emission testing was conducted using the ISO 8178 (D2) test cycle. When emissions testing was completed a series of underway and pierside test runs were conducted to accumulate the remaining engine hours, After all testing, the engine conditions were assessed again using a combination of visual inspection and oil analysis. The remainder of the test fuel will be used to conduct a long-term stability test. The setup, test, and results of this testing, currently underway, are reported here with a discussion of MARAD’s alternative fuels test initiative.

The PR30C-LE is a repowered six-axle, 2,240 kW (3,005 hp), line-haul locomotive that was introduced to the rail industry in 2009. The Caterpillar 3516C-HD Tier 2 engine is equipped with an exhaust aftertreatment module containing selective catalyst reduction (SCR) and diesel oxidation catalyst (DOC) technology. PR30C-LE exhaust emission testing was performed on test locomotive PRLX3004. Phase-1 of the test program included the following tasks: engine-out baseline emissions testing without the aftertreatment module installed, aftertreatment module installation, commissioning and degreening, and emissions testing with the aftertreatment. Emission results from testing without the aftertreatment module, referred to as the baseline configuration, indicated that PRLX3004 emissions were below Tier 2 EPA locomotive limits without aftertreatment. Emission test results with the DOC and SCR aftertreatment module showed a reduction in nitrogen oxides (NO x ) of 80 percent over the line-haul cycle, and 59 percent over the switcher cycle. Particulate matter (PM) was reduced by 43 percent over the line-haul cycle and 64 percent over the switcher cycle. Line-haul cycle composite emissions of Hydrocarbon (HC) and carbon monoxide (CO) were reduced by 93 and 72 percent, respectively. The PR30C-LE locomotive achieved Tier 4 line-haul NO x , CO, HC, as well as Tier 3 PM levels. There are currently five PR30C-LE locomotives in operation in California and Arizona, and the total hour accumulation of the five PR30C-LE locomotives as of October 2011 was 20,000 hours.

Reciprocating engines are still frequently used in aviation especially in applications such as recreation planes, taxi-planes, fire extinguishing aircraft and generally applications that do not require a high power density. For such applications they have a significant advantage against turbine engines as far as purchase and maintenance cost is concerned. The proper and efficient operation of these engines in aviation applications is critical and therefore techniques that are used to determine engine condition and to detect potential faults are extremely important. The performance of these engines depends strongly on the condition of the ignition system and the quality of the supplied mixture. For this reason in the present work it is examined the effect of mixture AFR on the combustion mechanism and engine performance using an existing diagnostic methodology for spark ignited engines developed by the present research group. The investigation is conducted on a radial, spark-ignited reciprocating engine used on the CL-215 fire extinguishing aircraft. The diagnostic technique is used to investigate the effect of AFR on the main combustion and performance characteristics of the engine and specifically brake power output, rate of heat release, cumulative heat release, peak firing pressure, ignition and injection timing and duration of combustion. Furthermore the diagnostic technique is used to derive information for spark advance, spark duration, compression condition etc. The diagnostic technique is based on a thermodynamic two-zone combustion model for spark ignited engines. To examine the effect of AFR on the combustion mechanism a detailed experimental investigation was conducted on an engine (radial, supercharged, air-cooled, eighteen-cylinders) mounted on a test bench. The measurement procedure involved measurements at various operating conditions (load and speed) and various AFR values. During the experimental investigation beyond the conventional test bench measurements, measurements were taken using a fast data acquisition system of cylinder pressure and the electric signal of both spark plugs. Engine diagnosis is established by processing of these measured data. From the results of the diagnosis procedure it is revealed that the diagnosis method provides detailed information for the operating condition of the engine and the values of parameters that cannot be measured on the field. The diagnosis results reveal that the proposed technique can determine the effect of AFR ratio on the combustion mechanism adequately and thus it can be used during engine testing to determine the optimum AFR ratio in combination with the remaining engine settings and mainly spark advance. The results obtained are positive and reveal that the proposed diagnostic technique can be easily applied on any type of spark-ignited engine and especially on aircraft piston engines (i.e. aviation applications), where the accurate estimation of the engine condition and settings is extremely important.

A 2009 Volkswagen Jetta was tested using a Portable Emissions Measurement System (PEMS) SemtechD emissions analyzer to determine when the emissions and fuel consumption will be the smallest in regards to startup vs. idle emissions. An idle time equivalent was calculated to determine when idle emissions became equal to startup emissions at four different ambient temperatures for a cold start. The mass of Total Hydrocarbons (THC) emitted limited the idle time equivalent to less than the startup time for all ambient temperatures. The temperature of the Catalytic Converter (CC) was monitored to determine how quickly the car cools down and therefore, how beneficial it is to turn the car off after a certain time period. For the temperature range tested, it was more beneficial for reduced emissions to turn off the car compared to idling by a factor of at least four. The data suggests a trend that idling would never be the best option; however, more testing needs to be done with a greater range of CC cool down temperatures to confirm this initial assessment.

Dresser Waukesha has developed a more robust piston capable of operating under abuse conditions beyond those typically seen for large industrial natural gas engines. The results of the modeling and experimental work used to develop and validate the new robust piston will be presented in this paper. Simulation tools were first used to gain a comprehensive understanding of the causes of piston scuffing when operated under abuse conditions. With this understanding, an improved design was developed and the design changes were compared to the original piston. The performance of the new design was then simulated and compared to the original design. To investigate the robustness of the new design, the effect of reducing the major diameter clearance beyond the print specification was studied. Wear loads were predicted to be insensitive to size variations and were predicted to be acceptable even to the limit of a cold piston/liner interference fit. The predicted robustness of the new design was confirmed with experimental testing.

Conventional switcher or shunting locomotives in North America are powered by a single 12 or 16 cylinder engine which operate at eight distinct power levels, plus idle. Recently introduced locomotive power systems utilize multiple smaller displacement non-road diesel engines packaged as individual generator sets to obtain a cleaner and more efficient locomotive. This paper examines exhaust emissions and fuel consumption of a Railpower RP20BD switcher locomotive utilizing three 375 kW e generators. FTP tests, described in part 92 of the CFR Title 40, were completed for UPY2606 using two fuels: EPA certification diesel, and ultra-low sulfur diesel. The locomotive produced emissions well below EPA Tier 2 limits using certification fuel, and subsequent testing with ULSD further reduced emissions to below the future EPA Tier 2 and 3 limits.

Dresser Waukesha has designed a new connecting rod for implementation on the VHP series of natural gas engines. The connecting rod design process was driven by feature based solid models which were readily accessed for finite element structural analysis, rapid prototyping, and production tooling procurement in order to minimize the overall development time. The main objectives of the design effort were higher speed/power rating capability and assembly compatibility with existing 8.50 inch and 9.375 inch bore field engines in both a lean burn and rich burn operating condition. This paper discusses the advanced utilization of finite element analysis and bench testing techniques to expedite the design and test validation process.

Engines performance and efficiency are largely influenced by the combustion phasing. Operating conditions and control settings influence the combustion development over the crankshaft angle: the most effective control parameter used by Electronic Control Units (ECU) to optimize the combustion process for Spark Ignition (SI) engines is Spark Advance (SA). SA mapping is a time-consuming process, usually carried out with the engine running in steady state on the test bench, changing SA values while monitoring Brake and Indicated Mean Effective Pressure (BMEP, IMEP) and Brake Specific Fuel Consumption (BSFC). Mean values of IMEP and BSFC for a test carried out with a given SA setting are considered as the parameters to optimize. However, the effect of SA on IMEP and BSFC is not deterministic, due to the cycle-to-cycle variation: the analysis of mean values requires many engine cycles to be significant of the performance obtained with the given control setting. Finally other elements, such as engine or components ageing, and disturbances like Air-to-Fuel Ratio (AFR) or air, water and oil temperature variations, could affect the tests results: this facet can be very significant for racing engines testing. This paper presents a novel approach to SA mapping, with the objective of improving the performance analysis robustness, while reducing the test time. The methodology is based on the observation that, for a given running condition, IMEP can be considered a function of the combustion phasing, represented by the 50% Mass Fraction Burned (MFB50) parameter. Due to cycle-to-cycle variation, many different MFB50 and IMEP values are obtained during a steady state test carried out with constant SA. While MFB50 and IMEP absolute values are influenced by disturbance factors, the relationship between them holds, and it can be synthesized by means of the angular coefficient of the tangent line to the MFB50-IMEP distribution. The angular coefficient variations as a function of SA can be used to feed a SA controller, able to maintain the optimal combustion phasing. Similarly, knock detection is approached by evaluating two indexes: the distribution of a typical knock-sensitive parameter (MAPO, Maximum Amplitude of Pressure Oscillations) is related to that of CHR NET (net Cumulative Heat Release), determining a robust knock index. A knock limiter controller can then be added, in order to restrict the SA range to safe values. The methodology can be implemented in real-time combustion controllers: the algorithms have been applied offline to sampled data, showing the feasibility of fast and robust automatic mapping procedures.

Motivated by the need to achieve greater efficiency in the product development cycle, engine manufacturers in the heavy-duty industry are relying more and more on analytical tools to help resolve performance issues, minimize testing costs and reduce time to market. This is particularly the case in the area of power cylinder development, since the physical phenomena occurring within the cylinders are difficult to observe and quantify. However, analytical tools are useful only if they are able to accurately represent the physical systems that they are supposed to simulate. It therefore becomes critical to establish a correlation between model predictions and empirical measurements. To this end, a correlation study was initiated comparing power cylinder analytical modeling results to empirical measurements in a John Deere 6135H 13.5L I-6 engine. The engine test measurements that were carried out included cylinder pressure, piston land pressure, engine blowby, and lube oil consumption. The correlation parameters considered in the study included piston land gas pressures, power cylinder contribution to engine blowby, and lube oil consumption mechanisms.

In 2007, certification standards for heavy duty diesel particulate matter (PM) emissions were reduced from 0.1g/bhp-hr to 0.01g/bhp-hr, representing an order of magnitude reduction in pollutant level. Coincident with these standards revisions are refinements to test procedures that target reductions in measurement uncertainties. The 2007 U.S. Environmental Protection Agency (US EPA) specifications, as defined in 40 CFR parts 86, and US EPA 2010 specifications, as defined in CFR 1065, require significant updates to established laboratory measurement systems and test procedures. Moreover, additional regulatory standards pertaining to in-use compliance of heavy duty diesel engines will significantly impact the future of heavy duty diesel emissions measurement. As a result of the reduced emission production levels, demand for ‘real-world’ emissions measurements, and subsequent development and evaluation of on-board emissions measurement systems, West Virginia University’s Center for Alternative Fuels, Engines, and Emissions (CAFEE) has designed and constructed, with support from the U.S. Department of Energy (DOE), the ‘next level’ transportable dual primary full-flow dilution tunnel emissions measurement laboratory. The objective of this project was to build a mobile emissions measurement laboratory, of engine test cell quality, that is capable of measuring regulated and non-regulated emissions, and meets US EPA 2007 and 2010 specifications. A thirty-foot long cargo container was constructed to house a portable emissions measurement facility, comprised of a High Efficiency Particulate Air (HEPA) primary dilution unit, two primary full-flow dilution tunnels, a subsonic venturi, a secondary particulate matter sampling system, a gaseous emissions analytical bench instrumentation system, a computer based data acquisition (DAQ) and control system, full air conditioning and ventilation system, and chassis dynamometer control systems. Dual tunnels, of 18 inches ID and 20 feet long provide dedicated measurement capability for both lower PM vehicles, as well as legacy diesel fueled vehicles. This provision reduces tunnel history effects between test programs which address differing exhaust composition and PM loading. The laboratory grade analytical system can be transported to virtually any location with a demand for emissions testing, either with or without WVU’s transportable medium or heavy duty chassis dynamometers. Alternatively, the system can be loaded onto a flatbed trailer in order to test emissions while a vehicle is operated over the road. This paper describes each sub-system of this transportable laboratory in the aspect of specifications and design considerations, and presents results of qualification tests on the laboratory.

This paper presents results from Phase 2 of the development of an Active Air Control (AAC) system to balance air flow into each cylinder of a turbocharged engine system, a PRCI-funded emissions reduction project. Imbalance in air flow creates a discontinuity in trapped equivalence ratio from cylinder to cylinder. Trapped equivalence ratio is directly proportional to NO X production and a function of the fuel flow rate, air flow rate, and, in a two-stroke cycle engine, the scavenging efficiency. Only when these three characteristics are balanced cylinder to cylinder will the combustion and the NO X production in each cylinder be equal. The engine NO X production will be disproportionately high if even one cylinder operates less lean relative to the other cylinders. This paper reports on the testing of an AAC system on a two-cylinder air flow bench at the National Gas Machinery Laboratory at Kansas State University. The results from these tests were then used to further validate the comprehensive, variable geometry, multi-cylinder flow model referred to as the Charge Air Integrated Manifold Engine Numerical Simulation (CAIMENS). CAIMENS is a manifold flow model coupled with the T-RECS engine processor that uses an integrated set of fundamental principles to determine the crank angle-resolved pressure, temperature, burned and unburned mass fractions, and gas exchange rates for the cylinder. CAIMENS has been validated with data from the NGML multi-cylinder flow bench. This information has allowed the research team to (1) quantify the impact of air flow imbalance and (2) provide detailed information leading to the specification of the active air flow control system. The end point of this project is an AAC system that can, with some engineering effort, be applied to field engines.

The objective of this work is to study the effect of different control parameters viz. EGR, fuel injection pressure and start of injection timing on exhaust emissions from diesel fueled HCCI combustion concept. A 4-cylinder LCV engine has been selected for experiments and FIRE 3D CFD software was used for simulation study. The basic idea of the simulation study is to find the suitable EGR ratio to run the engine on HCCI combustion mode so as to avoid any damage to the engine during testing. From simulation study, it was observed that the minimum EGR required for running the engine at 5.6 bar BMEP @ 2500 rpm in HCCI mode is approximately 45%. The trends of simulation results viz. soot and NOx emissions are closely following the experiments. The experiments were conducted at different loads at 2500 rpm and EGR varied from 0% to 60%. With increased EGR ratio, soot bump was observed at 50%, 75% and 100%. The BTE dropped to 24.5% from 33.5%. The effect of fuel injection pressures (750bar, 1000bar and 1500bar) were studied to improve the BTE and to control soot bump over a wide range injection timings EGR ratio. Detailed experiments were conducted at 2.8 bar BMEP @ 2500 rpm to study simultaneous reduction of NOx, SOOT, UHC and CO emissions from diesel HCCI combustion. At injection pressure (1500 bar), advanced fuel injection timing and high EGR ratio, the soot CO and THC emissions were reduced significantly without penalty on NOx emissions. The BTE was improved from 24.5% to 31% against 33.5% of convention diesel combustion.

A novel metal-based thermal barrier coating was tested in a spark-ignition engine. The coating was applied to the surface of aluminum plugs and exposed to in-cylinder conditions through ports in the cylinder wall. Temperatures were measured directly behind the coating and within the plug 3 and 11 mm from the surface. In-cylinder pressures were measured and analyzed to identify and quantify knock. Test results suggest the coating does not significantly reduce overall heat transfer, but it does reduce the magnitude of temperature fluctuations at the substrate surface. It was found that heat transfer can be reduced by reducing the surface roughness of the coating. The presence of the coating did not promote knock.

Continued regulatory pressure necessitates the use of precisely designed turbochargers to create the design trapped equivalence ratio within large-bore stationary engines used in the natural gas transmission industry. The upgraded turbochargers scavenge the exhaust gases from the cylinder, and create the air manifold pressure and backpressure on the engine necessary to achieve a specific trapped mass. This combination serves to achieve the emissions reduction required by regulatory agencies. Many engine owner/operators request that an upgraded turbocharger be tested prior to installing the turbocharger on the engine. The purpose of the test is to prevent field hardware iterations that are oftentimes necessary for the turbocharger to meet the air specification on the particular engine. Reworking a turbocharger due to not meeting the airflow and pressure requirement for emissions purposes can be quite costly and in many cases easily discovered through test-cell performance testing. Confirming the as-built turbocharger design specification prior to transporting the turbocharger to the field can decrease downtime and installation costs. There are, however, technical challenges that must be overcome to compare test-cell data to field conditions. This paper discusses the corrections that must be made to the test-cell data in order to determine how the turbocharger will perform on the engine. As the litmus test of the new testing system, performance data is corrected to site conditions verifying the air specification as designed by the end user. The correction method utilized herein is the ASME Power Test Code 10 (PTC-10) version 1997. Performance test data and the compressor map are corrected with the PTC-10 method to field conditions verifying turbocharger site performance before installation. After installation, data collected from the turbocharger operating on engine is compared with test corrected data, authenticating the turbocharger testing system and correction methods.

To meet the ignition system needs of large bore lean burn stationary natural gas engines a laser diode side pumped passively Q-switched laser igniter was developed and used to ignite lean mixtures in a single cylinder research engine. The laser design was produced from previous work. The in-cylinder conditions and exhaust emissions produced by the miniaturized laser were compared to that produced by a laboratory scale commercial laser system used in prior engine testing. The miniaturized laser design as well as the combustion and emissions data for both laser systems was compared and discussed. It was determined that the two laser systems produced virtually identical combustion and emissions data.