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This paper presents the results of engine and vehicle simulation modeling for a wide variety of individual technologies and technology packages applied to two medium-duty vocational vehicles. Simulation modeling was first conducted on one diesel and two gasoline medium-duty engines. Engine technologies were then applied to the baseline engines. The resulting fuel consumption maps were run over a range of vehicle duty cycles and payloads in the vehicle simulation model. Results were reported for both individual engine technologies and combinations or packages of technologies. Two vehicles, a Kenworth T270 box delivery truck and a Ford F-650 tow truck were evaluated. Once the baseline vehicle models were developed, vehicle technologies were added. As with the medium-duty engines, vehicle simulation results were reported for both individual technologies and for combinations. Vehicle technologies were evaluated only with the baseline 2019 diesel medium-duty engine.

This paper describes the potential for the use of Dedicated EGR® (D-EGR®) in a gasoline powered medium truck engine. The project goal was to determine if it is possible to match the thermal efficiency of a medium-duty diesel engine in Class 4 to Class 7 truck operations. The project evaluated a range of parameters for a D-EGR engine, including displacement, operating speed range, boosting systems, and BMEP levels. The engine simulation was done in GT-POWER, guided by experimental experience with smaller size D-EGR engines. The resulting engine fuel consumption maps were applied to two vehicle models, which ran over a range of 8 duty cycles at 3 payloads. This allowed a thorough evaluation of how D-EGR and conventional gasoline engines compare in fuel consumption and thermal efficiency to a diesel. The project results show that D-EGR gasoline engines can compete with medium duty diesel engines in terms of both thermal efficiency and GHG emissions.

Antilock brake systems for air braked vehicles have been growing in popularity in Great Britain and Europe and appear to be candidates for extensive use in the United States as well. Previous mandated use in the United States during the 1970's was not successful, in part because of reliability problems, and the National Highway Traffic Safety Administration (NHTSA) has decided that a thorough evaluation of air brake antilock systems is necessary prior to any decision about the appropriateness of future mandatory use in the United States. This paper describes the electronic data collection equipment and processing techniques which are being used in the NHTSA 200 truck evaluation project. Detailed maintenance histories for each truck are being recorded manually as a separate segment of the project. An average of 6 to 7 megabytes of data per week is being collected in the various cities in which fleets are operating test vehicles.

Commercial vehicles are moving in the direction of improving brake thermal efficiency while also meeting future diesel emission requirements. This study is focused on improving efficiency by replacing the variable geometry turbine (VGT) turbocharger with a high-efficiency fixed geometry turbocharger. Engine-out (EO) NOX emissions are maintained by providing the required amount of exhaust gas recirculation (EGR) using a 48 V motor driven EGR pump downstream of the EGR cooler. This engine is also equipped with cylinder deactivation (CDA) hardware such that the engine can be optimized at low load operation using the combination of the high-efficiency turbocharger, EGR pump and CDA. The exhaust aftertreatment system has been shown to meet 2027 emissions using the baseline engine hardware as it includes a close coupled light-off SCR followed by a downstream SCR system.

Criteria pollutants were measured from ten Class 7 and 8 (i.e., gross vehicle weights > 33,000 lb) heavy-duty diesel trucks with engine model years between 1953 and 1975. The data was used by EPA to estimate that period's particulate matter emission rates for these type engines and will be used to develop dose response relationships with existing epidemiological data. Particulate samples were analyzed for sulfate and volatile organic fraction. Carbon soot was estimated. The trucks had particulate emissions of 2 to 10 g/mi as compared to 1 to 6 g/mi for trucks with model year engines from 1975 through the mid-1980s, and less than 1 g/mi for post-1988 trucks.

The U.S. Army's National Automotive Center has contracted with Illinois Institute of Technology Research Institute (IITRI), Southwest Research Institute (SwRI), and Advanced Propulsion, LLC, to evaluate the effects on fuel consumption and logistics that would result from hybridizing the powertrains of the Army's tactical wheeled vehicle fleet. This paper will outline the approach taken to perform that evaluation and present a synopsis of results achieved to date.

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.

Exhaust emissions of non-methane hydrocarbon (NMHC) and methane were measured from a Tier 3 dual-fuel demonstration locomotive running diesel-natural gas blend. Measurements were performed with the typical flame ionization detector (FID) method in accordance with EPA CFR Title 40 Part 1065 and with an alternative Fourier-Transform Infrared (FTIR) Spectroscopy method. Measurements were performed with and without oxidation catalyst exhaust aftertreatment. FTIR may have potential for improved accuracy over the FID when NMHC is dominated by light hydrocarbons. In the dual fuel tests, the FTIR measurement was 1-4% higher than the FID measurement of. NMHC results between the two methods differed considerably, in some cases reporting concentrations as much as four times those of the FID. However, in comparing these data it is important to note that the FTIR method has several advantages over the FID method, so the differences do not necessarily represent error in the FTIR.

Several new or significantly upgraded heavy duty truck engines are being introduced in the North American market. One important aspect of these new or revised engines is their noise characteristics. This paper describes the noise related characteristics of the new DD15 engine, and compares them to other competitive heavy truck engines. DD15 engine features relevant to noise include a rear gear train, isolated oil pan and valve cover, and an amplified high pressure common rail fuel system. The transition between non-amplified and amplified common rail operation is shown to have a significant noise impact, not unlike the transition between pilot injection and single shot injection in some other engines.

A simulation framework with a validated system model capable of estimating fuel consumption is a valuable tool in analysis and design of the hybrid vehicles. In particular, the framework can be used for (1) benchmarking the fuel economy achievable from alternate hybrid powertrain technologies, (2) investigating sensitivity of fuel savings with respect to design parameters (for example, component sizing), and (3) evaluating the performance of various supervisory control algorithms for energy management. This paper describes such a simulation framework that can be used to predict fuel economy of series hydraulic hybrid vehicle for any specified driver demand schedule (drive cycle), developed in MATLAB/Simulink. The key components of the series hydraulic hybrid vehicle are modeled using a combination of first principles and empirical data. A simplified driver model is included to follow the specified drive cycle.

Vehicle to Everything (V2X) communication has enabled on-board access to information from other vehicles and infrastructure. This information, traditionally used for safety applications, is increasingly being used for improving vehicle fuel economy [1-5]. This work aims to demonstrate energy consumption reductions in heavy/medium duty vehicles using an eco-driving algorithm. The algorithm is enabled by V2X communication and uses data contained in Basic Safety Messages (BSMs) and Signal Phase and Timing (SPaT) to generate an energy-efficient velocity trajectory for the vehicle to follow. An urban corridor was modeled in a microscopic traffic simulation package and was calibrated to match real-world traffic conditions. A nominal reduction of 7% in energy consumption and 6% in trip time was observed in simulations of eco-driving trucks.

Southwest Research Institute (SwRI) converted two small air-cooled, gasoline engines to operate on LPG (sometimes called propane since propane is LPG's major constituent). Typical two- and four-cycle engines were chosen for this investigation. The two-cycle engine used was a McCulloch string trimmer engine with 28 cc displacement. The four-cycle engine used was an L-head, Tecumseh TVS90 with 148 cc displacement. These are typical of engines found on lower cost lawn mowers and string trimmers. The engines were baseline tested on gasoline, converted to LPG, and tested to determine equivalence ratios at which the engines could be operated without exceeding manufacturers' recommended spark plug seat or exhaust temperatures. Engine startability and throttle response was maintained with the LPG conversion. The emissions of the four-cycle engine were measured following the CARB 6-mode emissions test procedure.

Electromagnetic compatibility (EMC) design considerations have a vital role in the proper functioning of the electronic circuits and systems of a modern off-highway vehicle (OHV). Careful planning is needed in developing the electronic systems that operate the various functions and tasks on these vehicles. Incorporation of EMC in a system design gives that system the quality of reliability; that is, the system will have reduced emissions and be less susceptible to radiated and conducted electromagnetic energy. This paper provides ideas, concepts, and guidelines that the designer of OHV control circuitry can use for incorporation of EMC at the beginning of a design project.

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.

This paper presents a discussion on manual transmission torque losses and focuses specifically on the relationship between torque loss, input speed and torque. It also includes a discussion on other factors affecting torque loss, such as inclination angle and lube oil temperature. Manual transmissions used in compact light truck applications have torque losses that are a function of input speed and torque. Efficiency studies done on manual transmissions in the engine-driving mode indicate that torque losses, in other than direct-drive gears, are considerably more dependent on input torque than input speed. It was also observed that efficiency was significantly affected by the inclination angle and lube oil temperature.

An Emergency Tire Inflation System (ETIS) designed for use on commercial trucks was evaluated and tested. The ETIS is provided in kit form and designed to be installed by a truck operator to provide emergency air to inflate a low or punctured tire on tractor drive axles. The ETIS will continue to supply air to the tire until the system pressure falls below a safe air pressure level. The system is designed to allow the rig to be driven 500 miles to a tire repair station or to a safe location where tire repair service is available. The installation kit (Figure 1), which can fit under a truck seat, includes all the necessary equipment to install the system on the most common drive axles. The ETIS supplies air to the under-inflated tire through a previously qualified1 Rotary Union design. The Rotary Union is attached to the axle flange of the drive axle by a threaded adapter and two adjustable links that allow the Rotary Union to be placed at the center of rotation of the axle.

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.

Over twenty prototype hybrid buses and other commercial vehicles are currently being completed and deployed. These vehicles are primarily “series” hybrid vehicles which use electric motors for primary traction while internal combustion engines, or high-speed turbine engines connected to generators, supply some portion of the electric propulsion and battery recharge energy. Hybrid-electric vehicles have an electric energy storage system on board that influences the operation of the heat engine. The storage system design and level affect the vehicle emissions, electricity consumption, and fuel economy. Existing heavy-duty emissions test procedures require that the engine be tested over a transient cycle before it can be used in vehicles (over 26,000 lbs GVW). This paper describes current test procedures for assessing engine and vehicle emissions, and proposes techniques for evaluating engines used with hybrid-electric vehicle propulsion systems.

Regulated gaseous, particulate and several unregulated emissions are reported from four heavy-duty diesel engines operated on the chassis version of the 1983 transient procedure. Emissions were obtained from Caterpillar 3208, Mack ENDT 676, Cummins Formula 290 and Detroit Diesel 8V-71 engines with several diesel fuels. A large dilution tunnel (57′ × 46″ ID) was fabricated to allow total exhaust dilution, rather than the double dilution employed in the stationary engine version of the transient procedure. A modal particulate sampler was developed to obtain particulate data from the individual segments of the 1983 transient procedure. The exhaust gas was analyzed for benzo(a)pyrene, metals, N2O, NO2, individual hydrocarbons and HCN. Sequential extractions were performed and measured versus calculated fuel consumptions were obtained.

While initial Connected Vehicle research in the United States was focusing almost exclusively on passenger vehicles, a program was envisioned that would enhance highway safety, mobility, and operational efficiencies through the application of the technology to commercial vehicles. This program was realized in 2009 by funding from the I-95 Corridor Coalition, led by the New York State Department of Transportation, and called the Commercial Vehicle Infrastructure Integration (CVII) program. The CVII program focuses on developing, testing and deploying Connected Vehicle technology for heavy vehicles. Since its inception, the CVII program has developed numerous Vehicle-to-Vehicle and Vehicle-to-Infrastructure applications for trucks that leverage communication with roadside infrastructure and other light and heavy duty vehicles to meet the objectives of the program.