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This paper forms the third of a series and presents results obtained during the testing and development phase of a dedicated range extender engine designed for use in a compact class vehicle. The first paper in this series used real world drive logs to identify usage patterns of such vehicles and a driveline model was used to determine the power output requirements of a range extender engine for this application. The second paper presented the results of a design study. Key attributes for the engine were identified, these being minimum package volume, low weight, low cost, and good NVH. A description of the selection process for identifying the appropriate engine technology to satisfy these attributes was given and the resulting design highlights were described. The paper concluded with a presentation of the resulting specification and design highlights of the engine. This paper will present the resulting engine performance characteristics.

The addition of exhaust gas recirculation (EGR) has demonstrated the potential to significantly improve engine efficiency by allowing high CR operation due to a reduction in knock tendency, heat transfer, and pumping losses. In addition, EGR also reduces the engine-out emission of nitrogen oxides, particulates, and carbon monoxide while further improving efficiency at stoichiometric air/fuel ratios. However, improvements in efficiency through enhanced combustion phasing at high compression ratios can result in a significant increase in cylinder pressure. As cylinder pressure and temperature are both important parameters for estimating the durability requirements of the engine - in effect specifying the material and engineering required for the head and block - the impact of EGR on surface temperatures, when combined with the cylinder pressure data, will provide an important understanding of the design requirements for future cylinder heads.

Diesel Cylinder Deactivation (CDA) has been shown in previous work to increase exhaust temperatures, improve fuel efficiency, and reduce engine-out NOx for engine loads up to 3 bar BMEP. The purpose of this study is to determine whether or not the turbocharger needs to be altered when implementing CDA on a diesel engine. This study investigates the effect of CDA on exhaust temperature, fuel efficiency, and turbocharger performance in a 15L heavy-duty diesel engine under low-load (0-3 bar BMEP) steady-state operating conditions. Two calibration strategies were evaluated. First, a “stay-hot” thermal management strategy in which CDA was used to increase exhaust temperature and reduce fuel consumption. Next, a “get-hot” strategy where CDA and elevated idle speed was used to increase exhaust temperature and exhaust enthalpy for rapid aftertreatment warm-up.

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.

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.

A dynamometer test methodology was developed for evaluation of HMMWV axle efficiency with hypoid gearsets, comparing those having various degrees of superfinish versus new production axles as well as used axles removed at depot maintenance. To ensure real-world applicability, a HMMWV variant vehicle model was created and simulated over a peacetime vehicle duty cycle, which was developed to represent a mission scenario. In addition, tractive effort calculations were then used to determine the maximum input torques. The drive cycle developed above was modified into two different profiles having varying degrees of torque variability to determine if the degree of variability would have a significant influence on efficiency in the transient dynamometer tests. Additionally, steady state efficiency performance is measured at four input pinion speeds from 700-2500 rpm, five input torques from 50 - 400 N⋅m, and two sump temperatures, 80°C and 110°C.

There is growing interest in additive manufacturing technologies for prototype if not serial production of complex internal combustion engine components such as cylinder heads and pistons. In support of this general interest the authors undertook an experimental bench test to evaluate opportunities for cooling jacket improvement through geometries made achievable with additive manufacturing. A bench test rig was constructed using electrical heating elements and careful measurement to quantify the impact of various designs in terms of heat flux rate and convective heat transfer coefficients. Five designs were compared to a baseline - a castable rectangular passage. With each design the heat transfer coefficients and heat flux rates were measured at varying heat inputs, flow rates and pressure drops. Four of the five alternative geometries outperformed the baseline case by significant margins.

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.

A zero-dimensional cycle simulation model coupled with a chemical equilibrium model and a two-zone combustion model has been extended to predict nitric oxide formation and emissions from spark-ignited, lean-burn natural gas engines. It is demonstrated that using the extended Zeldovich mechanism alone, the NOx emissions from an 8.1-liter, 6-cylinder, natural gas engine were significantly under predicted. However, by combining the predicted NOx formation from both the extended Zeldovich thermal NO and the Fenimore prompt NO mechanisms, the NOx emissions were predicted with fair accuracy over a range of engine powers and lean-burn equivalence ratios. The effect of injection timing on NOx emissions was under predicted. Humidity effects on NOx formation were slightly under predicted in another engine, a 6.8-liter, 6-cylinder, natural gas engine. Engine power was well predicted in both engines, which is a prerequisite to accurate NOx predictions.

This paper will describe the fuel economy benefits that can be obtained when traditionally engine-driven accessories such as water pumps, oil pumps, power steering pumps, radiator cooling fans and air conditioning compressors are decoupled from the engine and are remotely driven and controlled. Simulation results for different vehicle configurations such as heavy duty trucks operated over urban and highway driving cycles and light duty vehicles such as mini vans will be presented. These results will quantify the heavy dependence of fuel economy benefits associated with different types of driving cycles.

A vehicle's gasoline fuel tank was removed and replaced with a 5,000-psig, Type-III, aluminum-lined hydrogen cylinder. High-pressure cylinders are typically installed with a thermally-activated pressure relief device (PRD) designed to safely vent the contents of the cylinder in the event of accidental exposure to fire. The objective of this research was to assess the results of a catastrophic failure in the event that a PRD were ineffective. Therefore, no PRD was installed on the vehicle to ensure cylinder failure would occur. The cylinder was pressurized and exposed to a propane bonfire in order to simulate the occurrence of a gasoline pool fire on the underside of the vehicle. Measurements included temperature and carbon monoxide concentration inside the passenger compartment of the vehicle to evaluate tenability. Measurements on the exterior of the vehicle included blast wave pressures. Documentation included standard, infrared, and high-speed video.

This paper analyzes the aging of zeolite based hydrocarbon traps to guide development of diagnostic algorithms. Previous research has shown the water adsorption ability of zeolite ages along with the hydrocarbon adsorption ability, and this leads to a possible diagnostic algorithm: the water concentration in the exhaust can be measured and related to aging. In the present research, engine experiments demonstrate that temperature measurements are also related to aging. To examine the relationship between temperature-based and moisture-based diagnostic algorithms, a transient, nonlinear heat and mass transfer model of the exhaust during cold-start is developed. Despite some idealizations, the model replicates the qualitative behavior of the exhaust system. A series of parametric studies reveals the sensitivity of the system response to aging and various noise factors.

The objective of this effort was to develop an understanding of how different converter substrate cell structures impact tailpipe emissions and pressure drop from a total systems perspective. The cell structures studied were the following: The catalyst technologies utilized were a new technology palladium only catalyst in combination with a palladium/rhodium catalyst. A 4.0-liter, 1997 Jeep Cherokee with a modified calibration was chosen as the test platform for performing the FTP test. The experimental design focused on quantifying emissions performance as a function of converter volume for the different cell structures. The results from this study demonstrate that the 93 square cell/cm2 structure has superior performance versus the 62 square cell/cm2 structure and the 46 triangle cell/cm2 structure when the converter volumes were relatively small. However, as converter volume increases the emissions differences diminish.

Brake energy recovery is one of the key components in today's hybrid vehicles that allows for increased fuel economy. Typically, major engineering changes are required in the drivetrain to achieve these gains. The objective of this paper is to present a concept of capturing brake energy in a mild hybrid approach without any major modifications to the drivetrain or other vehicular systems. With fuel costs rising, the additional component cost incurred in the presented concept may be recovered quickly. In today's vehicles, alternators supply the electrical power for the engine and vehicle accessories whenever the engine is running. As vehicle electrical demands increase, this load is an ever-increasing part of the engine's output, negatively impacting fuel economy. By using a regenerative device (alternator) on the drive shaft (or any other part of the power train), electrical energy can be captured during braking.

The VanDyne SuperTurbocharger (SuperTurbo) is a turbocharger with an integral Continuously Variable Transmission (CVT). By changing the gear ratio of the CVT, the SuperTurbo is able to either pull power from the crankshaft to provide a supercharging function, or to function as a turbo-compounder, where energy is taken from the turbine and given to the crankshaft. The SuperTurbo's supercharger function enhances the transient response of a downsized and turbocharged engine, and the turbo-compounding function offers the opportunity to extract the available exhaust energy from the turbine rather than opening a waste gate. Using 1-D simulation, it was shown that a 2.0-liter L4 could exceed the torque curve of a 3.2L V6 using a SuperTurbo, and meet the torque curve of a 4.2-liter V8 with a SuperTurbo and a fresh-air bypass configuration. In each case, the part-load efficiency while using the SuperTurbo was better than the baseline engine.

Real-time transient and steady-state oil consumption were measured on three SI-engines, applying two different ring-packs to each engine. Testing of multiple engines enables an assessment of the engine-to-engine variability in oil consumption. Testing of multiple ring-packs on each engine enables an assessment of the ring-pack-to-ring-pack variability in oil consumption. The oil consumption was measured by the Southwest Research Institute (SwRI) novel developed SO2-tracer technique, referred to as RTOC-III. An interesting finding is that the testing shows low engine-to-engine and ring-pack-to-ring-pack variability, in both steady-state, as well as in transient oil consumption. This suggests that the RTOC-III system did not introduce significant variability to the data. The testing results are experimental verification of a design and simulation exercise, in a field of scarcely published literature.

The electrification of accessories using a fuel cell as an auxiliary power unit reduces the load on the engine and provides opportunities to increase propulsion performance or reduce engine displacement. The SunLine™ Class 8 tractor electric accessory integration project is a United States Army National Automotive Center (NAC™) initiative in partnership with Cummins Inc., Dynetek™ Industries Ltd., General Dynamics C4 Systems, Acumentrics™ Corporation, Michelin North America, Engineered Machine Products (EMP™), Peterbilt™ Motors Company, Modine™ Manufacturing and Masterflux™. Southwest Research Institute is the technical integration contractor to SunLine™ Services Group. In this paper the SunLine™ tractor electric Air Conditioning (AC) system is described and the installation of components on the tractor is illustrated. The AC system has been designed to retrofit into an existing automotive system and every effort was made to maintain OEM components whenever modifications were made.

In off-highway applications the engine torque is distributed between the transmission (propulsion) and other accessories such as power steering, air conditioning and implements. Electronic controls offer the opportunity to more efficiently manage the control of the engine and transmission as an integrated system. This paper deals with development of a steepest descent algorithm for maximizing the efficiency of hydrostatic transmission along with the engine in the presence of accessory load. The methodology is illustrated with an example. The strategy can be extended to the full hydro-mechanical configuration as required. Applications of this approach include adjusting for component wear and intelligent energy management between different accessories for possible size reduction of powertrain components. The potential benefits of this strategy are improved fuel efficiency and operator productivity.

Computational Fluid Dynamics (CFD) analysis software is being developed by many companies and it is a valuable tool in designing hydraulic components. CFD analysis can provide accurate predictions of pressure drop in fluid flow paths and offer insight into the primary source of losses. When used in conjunction with solid modeling design software, the process of optimizing a design can be accomplished much quicker, reducing development costs and time. This paper presents a CFD analysis of an existing valve design and compares it to an improved design. The source of the primary losses of the existing valve will be identified which will lead to modifications to design features that minimize those losses. These modifications will be modeled and analyzed for predicted improvements. Pressure drop tests will be conducted on the original design to verify the analysis. Internal pressure loading of valve parts cannot easily be determined by testing.

It has been shown within the catalyst industry that the emission performance with higher cell density technology and therefore with higher specific geometric area is improved. The focus of this study was to compare the overall performance of high cell density catalysts, up to 1600cpsi, using a MY 2001 production vehicle with a 4.7ltr.V8 engine. The substrates were configured to be on the edge of the design capability. The goal was to develop cost optimized systems with similar emission and back pressure performance, which meet physical and production requirements. This paper will present the results of a preliminary computer simulation study and the final emission testing of a production vehicle. For the pre-evaluation a numerical simulation model was used to compare the light-off performance of different substrate designs in the cold start portion of the FTP test cycle.