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It is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards of 0.20 g/bhp-hr, the National Ambient Air Quality Standards (NAAQS) requirements for ambient ozone will not be met. It is expected that further reductions in NOX emissions from the heavy-duty fleet will be required to achieve compliance with the ambient ozone requirement. To study the feasibility of further reductions, the California Air Resources Board (CARB) funded a research program to demonstrate the potential to reach 0.02 g/bhp-hr NOX emissions. This paper details the work executed to achieve this goal on the heavy-duty Federal Test Procedure (FTP) with a heavy-duty natural gas engine equipped with a three-way catalyst. A Cummins ISX-12G natural gas engine was modified and coupled with an advanced catalyst system.

The diesel engine has long been the most energy efficient powerplant for transportation. Moreover, diesels emit extremely low levels of hydrocarbon and carbon monoxide that do not require post-combustion treatment to comply with current and projected standards. It is admittedly, however, difficult for diesel engines to simultaneously meet projected nitrogen oxides and particulate matter standards. Traditionally, measures aimed at reducing one of these two exhaust species have led to increasing the other. This physical characteristic, which is known as NOx/PM tradeoff, remains the subject of an intense research effort. Despite this challenge, there is significant evidence that heavy-duty highway engine manufacturers can achieve substantial emission reductions. Many development programs carried out over the last five years have yielded remarkable results in laboratory demonstrations.

The 2010 emissions standards for heavy-duty engines have established a limit of oxides of nitrogen (NOX) emissions of 0.20 g/bhp-hr. However, the California Air Resource Board (ARB) projects that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter (PM) and Ozone will not be achieved without further reduction in NOX emissions. The California Air Resources Board (CARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOX emissions.

Recent 2010 emissions standards for heavy-duty engines have established a limit of oxides of nitrogen (NOX) emissions of 0.20 g/bhp-hr. However, CARB has projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter and Ozone will not be achieved without further reduction in NOX emissions. The California Air Resources Board (ARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOX emissions. This paper details engine and aftertreatment NOX management requirements and model based control considerations for achieving Ultra-Low NOX (ULN) levels with a heavy-duty diesel engine. Data are presented for several Advanced Technology aftertreatment solutions and the integration of these solutions with the engine calibration.

The most recent 2010 emissions standards for heavy-duty engines have established a tailpipe limit of oxides of nitrogen (NOX) emissions of 0.20 g/bhp-hr. However, it is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter and Ozone will not be achieved without further reduction in NOX emissions. The California Air Resources Board (CARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOX emissions.

An Automatic Tire Inflation System (ATIS), specifically designed for use on commercial long haul trailers underwent complete testing and evaluation in 1993/1994.1 Testing and evaluation included a field test of a prototype system and a controlled laboratory evaluation of the Rotary Union which is the only component subject to wear. The testing of the prototype system indicated that design improvements were necessary before the system could be installed in fleet operations. The design improvements were completed and field installation of production ATIS began. The design improvements were intended to improve overall system durability, decrease installation time, to have less effect on the axle structure than the original design, implement the use of SAE or DOT Approved pressure components and increase overall dependability of the system. ATIS systems have now been developed and tested for most domestic trailer axle configurations.

Emissions from existing diesel-powered urban buses are increasingly scrutinized as local, state, and federal governments require enforcement of more stringent emission regulations and expectations. Currently, visual observation of high smoke levels from diesel-powered equipment is a popular indicator of potential emission problems requiring tune-up or engine maintenance. It is important that bus inspection and maintenance (I/M) operations have a quality control “test” to check engine emissions or diagnose the engine state-of-tune before or after maintenance. Ideally, the “emission test” would be correlated to EPA transient emissions standards, be of short duration, and be compatible with garage procedures and equipment. In support of developing a useful “short-test,” equipment was designed to collect samples of raw exhaust over a short time period for gaseous and particulate emissions.

This book will assist readers in meeting today's tough challenges of improving diesel engine emissions, diesel efficiency, and public perception of the diesel engine. It can be used as an introductory text, while at the same time providing practical information that will be useful for experienced readers. This comprehensive book is well illustrated with more than 560 figures and 80 tables. Each main section is broken down into chapters that offer more specific and extensive information on current issues, as well as answers to technical questions.

Semi-volatile organic compounds (SVOC) are a group of compounds in engine exhaust that either form during combustion or are part of the fuel and lubricating oil. Since these compounds occur at very low concentrations in diesel engine exhaust, the methods for sampling, handling, and analyzing these compounds are critical to obtaining good results. An improved dilute exhaust sampling method was used for sampling and analyzing SVOC in engine exhaust, and this method was performed during transient engine operation. A total of 22 different SVOC were measured using a 2012 medium-duty diesel engine. This engine was equipped with a stock diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst in series. Exhaust concentrations for SVOC were compared both with and without exhaust aftertreatment. Concentrations for the engine-out SVOC were significantly higher than with the aftertreatment present.

The key words in the marketplace for off-highway vehicles are durability, performance, and efficiency. A manufacturer of these vehicles recognizes that one way to successfully address these needs is by a well thought through electronics design. With the computer sophistication now being incorporated into off-highway vehicles, engineers must work closely to assure electromagnetic compatibility (EMC) of the entire system. A properly established EMC program extending from concept to final design will support each of a product's specified operations and still function as an integrated whole. This paper describes the process for designing the EMC for an off-highway vehicle.

Electromagnetic immunity (EMI) for off-highway vehicles (OHV) is a vehicle's ability to resist radiated and conducted electromagnetic interference. Interference can originate within the OHV from the various systems designed to control its operational functions; external sources can also cause serious disruption of the electronic control mechanisms. Knowledge of how and where interferences originate gives the electronic designer insight into how to avoid the pitfalls which can cause malfunctions. Verification of designs through testing will ensure that safety and reliability are built into every OHV produced. This paper discusses the mechanisms that cause susceptibility of electronic circuits to electromagnetic interference, and presents test methods to help the designer improve circuit design and verify the immunity of the complete vehicle. This is the second in a series of papers on electromagnetic compatibility (EMC) in the off-highway vehicle.

Selective Catalytic Reduction (SCR) systems provide excellent NOX control for diesel engines provided the exhaust aftertreatment inlet temperature remains at 200° C or higher. Since diesel engines run lean, extended light load operation typically causes exhaust temperatures to fall below 200° C and SCR conversion efficiency diminishes. Heated urea dosing systems are being developed to allow dosing below 190° C. However, catalyst face plugging remains a concern. Close coupled SCR systems and lower temperature formulation of SCR systems are also being developed, which add additional expense. Current strategies of post fuel injection and retarded injection timing increases fuel consumption. One viable keep-warm strategy examined in this paper is cylinder deactivation (CDA) which can increase exhaust temperature and reduce fuel consumption.

California Air Resources Board (CARB) has instituted requirements for on-board diagnostics (OBD) that makes a spark-plug sized exhaust particulate matter (PM) sensor a critical component of the OBD system to detect diesel particulate filter (DPF) failure. Currently, non-real-time resistive-type sensors are used by engine OEMs onboard vehicles. Future OBD regulations are likely to lower PM OBD thresholds requiring higher sensitivity sensors with better data yield for OBD decision making. The focus of this work was on the experimental evaluation of a real-time PM sensor manufactured by EmiSense Technologies, LLC that may offer such benefits. A 2011 model year on-highway heavy-duty diesel engine fitted with a diesel oxidation catalyst (DOC) and a catalyzed DPF followed by urea-based selective catalytic reducer (SCR) and ammonia oxidation (AMOX) catalysts was used for this program.

Multiple areas in the U.S. continue to struggle with achieving National Ambient Air Quality Standards for ozone. These continued issues highlight the need for further reductions in NOX emission standards in multiple industry sectors, with heavy-duty on-highway engines being one of the most important areas to be addressed. Starting in 2014, CARB initiated a series of technical demonstration programs aimed at examining the feasibility of achieving up to a 90% reduction in tailpipe NOX, while at the same time maintaining a path towards GHG reductions that will be required as part of the Heavy-Duty Phase 2 GHG program. These programs culminated in the Stage 3 Low NOX program, which demonstrated low NOX emissions while maintaining GHG emissions at levels comparable to the baseline engine.

This paper reviews the technologies available for Bharat Stage 3 and 4 Heavy Duty on-highway emissions standards. Benchmarking data from several existing engines is used to explore the trade-offs between engine/vehicle cost and fuel consumption. Other implications of the available technologies, such as durability / reliability requirements, are also addressed. The paper provides recommendations for low cost approaches to meeting Bharat Stage 3 and 4 standards with good fuel consumption and reliability/ durability characteristics. A brief look ahead to future Bharat Stage 5 requirements is also provided.

Combustion losses are one of the largest areas on inefficiency in natural gas/diesel dual-fuel engines, especially when compared to the traditional diesel engines on which they are based. These losses can vary from 1-2% at high load, to more than 6% of the total fuel energy at part load conditions. For diesel/natural gas dual-fuel engines, the three main sources of combustion losses are: bulk losses (increasing air-fuel ratio, AFR, to the premixed fuel’s lean flammability limit), crevice losses (premixed fuel trapped near valve pockets and top ring lands unable to oxidize), and blow-through losses (fumigated fuel/air intake charge passes through the cylinder and out the exhaust valve during valve overlap). In order to improve overall engine efficiency and decrease greenhouse gas emissions, these losses must be minimized.

The purpose in doing probabilistic structural analysis is to provide the designer with a more realistic ability to assess the importance of uncertainty in the structural response. This paper provides an overview of the methodology and discusses validation of modular structural analysis packages capable of predicting the probabilistic response distribution for key structural variables such as stress, displacement, natural frequencies, buckling loads, transient responses, etc. The structural analysis solution is in terms of the cumulative distribution function (CDF). Probabilistic structural analysis methods (PSAM) can be used to estimate structural safety and reliability, while providing the engineer with information on the confidence that should be given to the predicted behavior.

An Automatic Tire Inflation System (ATIS), specifically designed for use on commercial long haul trailers, requires modification of the axles to direct air to the tires. The ATIS requires a drilled hole through the axle tube for the installation of a pneumatic fitting. The trucking industry expressed concern about the modification and its impact upon the axle structure, and the general durability of the system over a long period. A three-phase test program was developed and conducted to satisfy the concerns of the industry.

Solid and metallic ash particle number (PN) and particulate matter (PM) mass emission measurements were performed on a heavy-duty (HD) on-highway diesel engine and a compressed natural gas (CNG) engine. Measurements were conducted under transient engine operation that included the FTP, WHTC and RMC. Both engines were calibrated to meet CARB ultra low NOX emission target of 0.02 g/hp-hr, a 90% reduction from current emissions limit. The HD diesel engine final exhaust configuration included a number of aftertreatement sub-systems in addition to a selective catalytic reduction filter (SCRF). The stoichiometric CNG engine final configuration included a closed coupled Three Way Catalyst (ccTWC) and an under floor TWC (ufTWC). The aftertreatment systems for both engines were aged for a full useful life (FUL) of 435,000 miles, prior to emissions testing. PM mass emissions from both engines were comparable and well below the US EPA emissions standard.

As governmental agencies focus on low levels of the oxides of nitrogen (NOx) emissions compliance, new off-road applications are being reviewed for both regulated and unregulated emissions to understand the technological challenges and requirements for improved emissions performance. The California Air Resources Board (CARB) has declared its intention to pursue more stringent NOX standards for the off-road market. As part of this effort, CARB initiated a program to provide a detailed characterization of emissions meeting the current Tier 4 off-road standards [1]. This work focused on understanding the off-road market, establishing a current technology emissions baseline, and performing initial modeling on potential low NOx solutions. This paper discusses a part of this effort, focuses on the emissions characterization from two non-road engine platforms, and compares the emissions species from different approaches designed to meet Tier 4 emissions regulations.