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With increasing energy prices and concerns about the environmental impact of greenhouse gas (GHG) emissions, a growing number of national governments are putting emphasis on improving the energy efficiency of the equipment employed throughout their transportation systems. Within the U.S. transportation sector, energy use in commercial vehicles has been increasing at a faster rate than that of automobiles. A 23% increase in fuel consumption for the U.S. heavy duty truck segment is expected from 2009 to 2020. The heavy duty vehicle oil consumption is projected to grow while light duty vehicle (LDV) fuel consumption will eventually experience a decrease. By 2050, the oil consumption rate by LDVs is anticipated to decrease below 2009 levels due to CAFE standards and biofuel use. In contrast, the heavy duty oil consumption rate is anticipated to double. The increasing trend in oil consumption for heavy trucks is linked to the vitality, security, and growth of the U.S. and global economies.

Future light duty vehicles in the United States are required to be certified on the FTP-75 cycle to meet Tier 3 or LEV III emission standards [1, 2]. The cold phase of this cycle is heavily weighted and mitigation of emissions during this phase is crucial to meet the low tail pipe emission targets [3, 4]. In this work, a novel aftertreatment architecture and controls to improve Nitrogen Oxides (NOx) and Hydrocarbon (HC) or Non Methane Organic gases (NMOG) conversion efficiencies at low temperatures is proposed. This includes a passive NOx & HC adsorber, termed the diesel Cold Start Concept (dCSC™) catalyst, followed by a Selective Catalytic Reduction catalyst on Filter (SCRF®) and an under-floor Selective Catalytic Reduction catalyst (SCR). The system utilizes a gaseous ammonia delivery system capable of dosing at two locations to maximize NOx conversion and minimize parasitic ammonia oxidation and ammonia slip.

This study analyzed the impact of transient and multi-mode engine conditions on emissions of dioxins and furans from a variety of diesel aftertreatment configurations. Exhaust aftertreatment systems included combinations of diesel oxidation catalyst, diesel particulate filter, and either Cu/zeolite or Fe/zeolite selective catalytic reduction catalyst. EPA method TO-9A was modified for proportional exhaust gas sampling, whereas EPA method 0023A was modified for raw exhaust gas sampling. Dioxin and furan emissions were first measured with modified method TO-9A during Federal Test Procedure transient cycles, but no toxic dioxins or furans were detected. Measurements were then taken with modified method 0023A during Ramped Mode Cycles-Supplemental Emissions Test experiments. Because more rigorous pre-cleaning and sample extraction procedures were used with this method and lower detection limits were achieved by the analytical laboratory, some dioxin and furan congeners were detected.

Real-world operation of diesel oxidation catalysts (DOCs), used in a variety of aftertreatment systems, subjects these catalysts to a large number of permanent and temporary deactivation mechanisms. These include thermal damage, induced by generating exotherm on the catalyst; exposure to various inorganic species contained in engine fluids; and the effects of soot and hydrocarbons, which can mask the catalyst in certain operating modes. While some of these deactivation mechanisms can be accurately simulated in the lab, others are specific to particular engine operation regimes. In this work, a set of DOCs, removed from prolonged service in the field, has been subjected to a detailed laboratory study. Samples obtained from various locations in these catalysts were used to characterize the extent and distribution of deactivation.

In August of 2011, the US Environmental Protection Agency issued new Green House Gas (GHG) emissions regulations for heavy duty vehicles. These regulations included new procedures for the evaluation of hybrid powertrains and vehicles. One of the hybrid options allows for the evaluation of an engine plus a hybrid transmission (a powertrain). For this type of testing, EPA has proposed simulating a vehicle following the hybrid vehicle test procedures, including the use of the vehicle cycles and the A to B comparison testing - as required for the full vehicle evaluation option. This paper proposes an alternative approach by defining a powertrain cycle. The powertrain cycle is based on the heavy duty engine emissions cycle - the transient FTP cycle. Simulation and test results are presented showing similar performance over the engine and vehicle cycles. This approach offers several advantages as compared to the procedure described in EPA's GHG rule.

Light duty vehicle emission standards are getting more stringent than ever before as stipulated by US EPA Tier 2 Standards and LEV III regulations proposed by CARB. The research in this paper sponsored by US DoE is focused towards developing a Tier 2 Bin 2 Emissions compliant light duty pickup truck with class leading fuel economy targets of 22.4 mpg “City” / 34.3 mpg “Highway”. Many advanced technologies comprising both engine and after-treatment systems are essential towards accomplishing this goal. The objective of this paper would be to discuss key engine technology enablers that will help in achieving the target emission levels and fuel economy. Several enabling technologies comprising air-handling, fuel system and base engine design requirements will be discussed in this paper highlighting both experimental and analytical evaluations.

This paper describes the development vehicle cycles based on heavy duty engine test cycles for emissions certification. In the commercial vehicle and industrial equipment markets, emissions are evaluated using engine test cycles. For the on-highway market in the United States, these cycles include the transient heavy duty engine FTP test, and the steady state heavy duty engine SET test. Evaluation of engine only emissions is a practical approach given the diversity of applications, small volumes, and lack of vertical integration in the commercial vehicle market. However certain vehicle and powertrain characteristics can contribute significantly to fuel consumption and emissions. A number of approaches have been proposed to evaluate vehicle performance, and all of these vehicle evaluation methodologies require the selection of a vehicle cycle.

This paper presents the business purpose, software architecture, technology integration, and applications of the Cummins Vehicle Mission Simulation (VMS) software. VMS is the value-based analysis tool used by the marketing, sales, and product engineering functions to simulate vehicle missions quickly and to gauge, communicate, and improve the value proposition of Cummins engines to customers. VMS leverages the best of software architecture practices and proven technologies available today. It consists of a close integration of MATLAB and Simulink with Java, XML, and JDBC technologies. This Windows compatible application software uses stand-alone mathematical models compiled using Real Time Workshop. A built-in MySQL database contains product data for engines, driveline components, vehicles, and topographic routes. This paper outlines the database governance model that facilitates effective management, control, and distribution of engine and vehicle data across the enterprise.

Cummins has studied requirements of the Light Truck Automotive market in the United States and believes that the proposed V-family of engines meets those needs. Design and development of the V-family engine system continues and has expanded. The engine system is a difficult one, since the combined requirements of a very fuel-efficient commercial diesel, and the performance and sociability requirements of a gasoline engine are needed. Results of testing show that the engine can meet requirements for fuel economy and emissions in the Tier 2 interim period from 2004 to 2008. Advanced results show that the full Tier 2 results for 2008 and beyond can be achieved on a laboratory basis.

Based on our error budget analysis, the urea SCR aftertreatment system is uncontrollable under EPA 2007-emission level without an effective closed-loop control strategy. The objective of the closed-loop control is to improve transient response as well as reduce the steady state control error. But the inherent large dead time in the urea SCR aftertreatment system makes the closed-loop control a challenge. In this paper, an innovative closed-loop control architecture is introduced, which combines model-based feedforward control with variable gain-scheduling feedback control. Transient response is improved with the inverse-dynamic feedforward control and the variable-gain closed-loop control. The steady-state response is improved with the closed-loop control. Based on this new strategy, a controller is designed and validated under the simulation and test cell environment. Comparison with the baseline open-loop controller is also conducted. Finally, some conclusions are presented.

Cummins Westport Inc. (CWI) released for production the latest version of its C8.3G natural gas engine, the C Gas Plus, in July 2001. This engine has increased ratings for horsepower and torque, a full-authority engine controller, wide tolerance to natural gas fuel (the minimum methane number is 65), and improved diagnostics capability. The C Gas Plus also meets the California Air Resources Board optional low-NOx (2.0 g/bhp-h) emission standard for automotive and urban buses. Two pre-production C Gas Plus engines were operated in a Viking Freight fleet for 12 months as part of the U.S. Department of Energy's Fuels Utilization Program. In-use exhaust emissions, fuel economy, and fuel cost were collected and compared with similar 1997 Cummins C8.3 diesel tractors. CWI and the West Virginia University developed an ad-hoc test cycle to simulate the Viking Freight fleet duty cycle from in-service data collected with data loggers.

Commercial Cu-Zeolite SCR catalyst can store and subsequently release significant amount of H2O. The process is accompanied by large heat effects. It is critical to model this phenomenon to design aftertreatment systems and to provide robust tuning strategies to meet cold start emissions and low temperature operation. The complex reaction mechanism of water adsorption and desorption over a Cu-exchanged SAPO-34 catalyst at low temperature was studied through steady state and transient experiments. Steady state isotherms were generated using a gravimetric method and then utilized to predict water storage interactions with respect to feed concentration and catalyst temperature. Transient temperature programmed desorption (TPD) experiments provided the kinetic information required to develop a global kinetic model from the experimental data. The model captures fundamental characteristics of water adsorption and desorption accompanied by the heat effects.

Engine noise is one of the significant aspects of product quality for light and medium duty diesel engine market applications. Gear whine is one of those noise issues, which is considered objectionable and impacts the customer’s perception of the product quality. Gear whine could result due to defects in the gear manufacturing process and/or due to inaccurate design of the gear macro and micro geometry. The focus of this technical paper is to discuss gear whine considerations from the production plant perspective. This includes quick overview of the measurement process, test cell environment, noise acceptance criteria considerations. A gear whine case study is presented based on the data collected in the test cell at the engine plant. Gear whine data acquired on current product and next generation of prototype engines is analyzed and presented. This paper concludes by highlighting the lessons learned from the case study.

This paper presents an extension of our earlier work on Cummins Vehicle Mission Simulation (VMS) software. Previously, we presented VMS as a Windows based analysis tool to simulate vehicle missions quickly and to gauge, communicate, and improve the value proposition of Cummins engines to customers. We have subsequently extended this VMS architecture to build a grid-computing platform to support high volume of simulation needs. The building block of the grid-computing version of VMS is an executable file that consists of vehicle and engine simulation models compiled using Real Time Workshop. This executable file integrates MATLAB and Simulink with Java, XML, and JDBC technologies and interacts with the MySQL database. Our grid consists of a cluster of twenty Linux servers with quad-core processors. The Sun Grid Engine software suite that administers this cluster can batch-queue and execute 80 simulations concurrently.

Diesel engine cylinder deactivation (CDA) can be used to reduce petroleum consumption and greenhouse gas (GHG) emissions of the global freight transportation system. Heavy duty trucks require complex exhaust aftertreatment (A/T) in order to meet stringent emission regulations. Efficient reduction of engine-out emissions require a certain A/T system temperature range, which is achieved by thermal management via control of engine exhaust flow and temperature. Fuel efficient thermal management is a significant challenge, particularly during cold start, extended idle, urban driving, and vehicle operation in cold ambient conditions. CDA results in airflow reductions at low loads. Airflow reductions generally result in higher exhaust gas temperatures and lower exhaust flow rates, which are beneficial for maintaining already elevated component temperatures. Airflow reductions also reduce pumping work, which improves fuel efficiency.

Government agencies like EPA play an important role through regulation to reduce emissions and fuel consumption and to drive technological developments to reduce the environmental impact of burning petroleum fuels. Emissions testing and control is one of the leading and growing fields in the development of modern vehicles. Recently, Cummins Emissions Solutions (CES) and Southwest Research Institute (SwRI) worked jointly in order to achieve a method to conduct emissions testing efficiently and effectively. The collaborative work between the two organizations led to the usage of FOCAS HGTR™ (a diesel-based burner test rig at SwRI) to simulate the exhaust conditions generated by a 2010 ISX Cummins production engine operating over an EPA standard Ramped Modal Cycle Supplemental Emissions Test (RMC SET) cycle.

Sustained NOx reduction at low temperatures, especially in the 150-200 °C range, shares some similarities with the more commonly discussed cold-start challenge, however, poses a number of additional and distinct technical problems. In this project, we set a bold target of achieving and maintaining 90% NOx conversion at the SCR catalyst inlet temperature of 150 °C. This project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015 and completed in 2017.

The influence of gasoline quality on exhaust emissions has been evaluated using four modern European gasoline cars with advanced features designed to improve fuel economy and CO2 emissions, including stoichiometric direct injection, lean direct injection and MPI with variable valve actuation. Fuel effects studied included sulphur content, evaluated over a range from 4 to 148 mg/kg, and other gasoline properties, including aromatics content, olefins content, volatility and final boiling point (FBP). All four cars achieved very low emissions levels, with some clear differences between the vehicle technologies. Even at these low emissions levels, all four cars showed very little short-term sensitivity to gasoline sulphur content. The measured effects of the other gasoline properties were small and often conflicting, with differing directional responses for different vehicles and emissions.

The modern diesel engine is used around the world to power applications as diverse as passenger cars, heavy-duty trucks, electrical power generators, ships, locomotives, agricultural and industrial equipment. The success of the diesel engine results from its unique combination of fuel economy, durability, reliability and affordability - which drive the lowest total cost of ownership. The diesel engine has been developed to meet the most demanding on-highway emission standards, through the introduction of advanced technologies such as: electronic controls, high pressure fuel injection, and cooled exhaust gas recirculation. The standards to be introduced in the U.S. in 2007 will see the introduction of the Clean Diesel which will achieve near-zero NOx and particulate emissions, while retaining the customer values outlined above.

The influence of big-end bore fretting on connecting rod fatigue fracture is investigated. A finite element model, including rod-bearing contact interaction, is developed to simulate a fatigue test rig where the connecting rod is subjected to an alternating uniaxial load. Comparison of the model results with a rod fracture from the fatigue rig shows good correlation between the fracture location and the peak ‘Ruiz’ criterion, rather than the peak tensile stress location, indicating the potential of fretting to initiate a fatigue fracture and the usefulness of the ‘Ruiz’ criterion as a measure of location and severity. The model is extended to simulate a full engine cycle using pressure loads from a bearing EHL analysis. A fretting map and a ‘Ruiz’ criterion map are developed for the full engine cycle, giving an indication of a safe ‘Ruiz’ level from an existing engine which has been in service for more than 5 years.