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Catalyzed Particulate Filter Passive Oxidation Study with ULSD and Biodiesel Blended Fuel

2012-06-18
A 2007 Cummins ISL 8.9L direct-injection common rail diesel engine rated at 272 kW (365 hp) was used to load the filter to 2.2 g/L and passively oxidize particulate matter (PM) within a 2007 OEM aftertreatment system consisting of a diesel oxidation catalyst (DOC) and catalyzed particulate filter (CPF). Having a better understanding of the passive NO2 oxidation kinetics of PM within the CPF allows for reducing the frequency of active regenerations (hydrocarbon injection) and the associated fuel penalties. Being able to model the passive oxidation of accumulated PM in the CPF is critical to creating accurate state estimation strategies. The MTU 1-D CPF model will be used to simulate data collected from this study to examine differences in the PM oxidation kinetics when soy methyl ester (SME) biodiesel is used as the source of fuel for the engine.
Technical Paper

Balancing Stack, Air Supply, and Water/Thermal Management Demands for an Indirect Methanol PEM Fuel Cell System

2001-03-05
2001-01-0535
This work presents a method to maximize the net power output of an indirect methanol PEM fuel cell system. This method establishes an operating strategy for the air supply based on the stack, air supply and water and thermal management (WTM) sub-system characteristics - holding anode conditions constant. It is shown that operating strategies based on individual components result in the inefficient operation of the overall system. Inclusion of the WTM modifies the optimal operating conditions for both low and high pressure systems. However the results for high pressure show an efficiency gain through reducing air pressure and increasing airflow, the opposite of what is expected. This work also outlines the components and issues not included and their importance in system operation.
Technical Paper

A Comparison of High-Pressure and Low-Pressure Operation of PEM Fuel Cell Systems

2001-03-05
2001-01-0538
This paper compares the merits of operating a direct-hydrogen fuel cell (DHFC) system using a high-pressure air supply (compressor) versus one using a low-pressure air supply (blower). Overall, for the system modeled, it is shown that there is no inherent performance advantage for either mode of operation at the DHFC stack level. However, in practical applications, as will be shown in this paper, a systems analysis (stack and air supply) of power and efficiency needs to be performed. Equivalent PEM DHFC stack peak power values can be obtained using both high-pressure and low-pressure air supply systems. For each air supply configuration, air mass flow and pressure operating conditions can be found that result in an equal value of the oxygen partial pressure at the cathode catalyst layer surface. However, at the system level, the required air supply power needed to achieve the same DHFC stack performance values can be drastically different for high and low pressure operation.
Technical Paper

Steam Reformer/Burner Integration and Analysis for an Indirect Methanol Fuel Cell Vehicle Fuel Processor

2001-03-05
2001-01-0539
This paper focuses on the impact of proper thermal integration between two major components of the indirect methanol fuel cell vehicle fuel processor (reformer and burner). The fuel processor uses the steam reformation of methanol to produce the hydrogen required by the fuel cell. Since the steam reformation is an endothermic process, the required thermal energy is supplied by a catalytic burner. The performance of the fuel processor is very strongly influenced by the extent of thermal integration between the reformer and burner. Both components are modeled as a set of CSTRs (Continuous Stirred Tank Reactors) using Matlab/Simulink. The current model assumes no time lag between the methanol sent into the reformer and the methanol sent into the burner to generate the necessary heat for the reformer reactions to occur.
Technical Paper

The Hybridized Fuel Cell Vehicle Model of the University of California, Davis

2001-03-05
2001-01-0543
Vehicle manufacturers claim that fuel cell vehicles are significantly more fuel-efficient and emit fewer emissions than conventional internal combustion engine vehicles /1/. A computer model can help to explore and understand the underlying reasons for this potential improvement. In previous published work, the UC Davis Vehicle Model for the case of a load-following Indirect Methanol Fuel Cell Vehicle (IMFCV) has been introduced and discussed in detail /2/. Because of possible technical barriers with load following vehicles, as well as near term cost issues, hybrid fuel cell vehicle concepts are widely discussed as another fuel cell vehicle option. For load following vehicles, the questions of fast start up and fuel processor dynamics in extreme transient situations, (e.g., during phases of hard acceleration) are not totally resolved at this time. For both of these performance issues, a hybrid design could offer at least an interim solution.
Technical Paper

Control Strategies for a Series-Parallel Hybrid Electric Vehicle

2001-03-05
2001-01-1354
Living in the era of rising environmental sensibility and increasing gasoline prices, the development of a new environmentally friendly generation of vehicles becomes a necessity. Hybrid electric vehicles are one means of increasing propulsion system efficiency and decreasing pollutant emissions. In this paper, the series-parallel power-split configuration for Michigan Technological University's FutureTruck is analyzed. Mathematical equations that describe the hybrid power-split transmission are derived. The vehicle's differential equations of motion are developed and the system's need for a controller is shown. The engine's brake power and brake specific fuel consumption, as a function of its speed and throttle position, are experimentally determined. A control strategy is proposed to achieve fuel efficient engine operation. The developed control strategy has been implemented in a vehicle simulation and in the test vehicle.
Technical Paper

Diesel Engine Electric Turbo Compound Technology

2003-06-23
2003-01-2294
A cooperative program between the DOE Office of Heavy Vehicle Technology and Caterpillar is aimed at demonstrating electric turbo compound technology on a Class 8 truck engine. The goal is to demonstrate the level of fuel efficiency improvement attainable with an electric turbocompound system. The system consists of a turbocharger with an electric motor/generator integrated into the turbo shaft. The generator extracts surplus power at the turbine, and the electricity it produces is used to run a motor mounted on the engine crankshaft, recovering otherwise wasted energy in the exhaust gases. The electric turbocompound system also provides more control flexibility in that the amount of power extracted can be varied. This allows for control of engine boost and thus air/fuel ratio. The paper presents the status of development of an electric turbocompound system for a Caterpillar heavy-duty on-highway truck engine.
Technical Paper

A Study of the Vapor- and Particle-Phase Sulfur Species in the Heavy-Duty Diesel Engine EGR Cooler

1998-05-04
981423
To meet future NO, heavy-duty diesel emissions standards, exhaust gas recirculation (EGR) technology is likely to be used. To improve fuel economy and further lower emissions, the recirculated exhaust gas needs to be cooled, with the possibility that cooling of the exhaust gas may form sulfuric acid condensate in the EGR cooler. This corrosive condensate can cause EGR cooler failure and consequentially result in severe damage to the engine. Both a literature review and a preliminary experimental study were conducted. In this study, a manually controlled EGR system was installed on a 1995 Cummins Ml l-330E engine which was operated at EPA mode 9* (1800 rpm and 75% load). The Goksoyr-Ross method (1)** was used to measure the particle-phase sulfate and vapor-phase H2SO4 and SO2 at the inlet and outlet locations of the EGR cooler, obtaining H2SO4 and SO2 concentrations. About 0.5% of fuel sulfur in the EGR cooler was in the particle-phase.
Technical Paper

Hybrid Electric Vehicle Development at the University of California, Davis: The Design of Ground FX

1994-03-01
940340
The last few years have been an exciting time for alternative vehicle development. New concerns about the environmental impact of personal transportation and about the United States' dependence on imported oil have pushed energy efficient, ultra-low, and zero emissions vehicles to the forefront of automotive design. California's own mandate for Zero Emissions Vehicles (ZEV) takes effect in 1998, creating a tremendous push towards the difficult goal of producing a commercially viable, practical electric vehicle for sale in 1998. Beyond California, most of the world's automakers are simultaneously committing tremendous research and development resources towards the technology necessary for a viable electric vehicle. The University of California at Davis is one of seven California universities participating in the 1993 Ford Hybrid Electric Vehicle Challenge.
Technical Paper

Development of Plasma Spray Coated Cylinder Liners

1996-02-01
960048
Improved fuel economy and reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, such insulation will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150°C to over 300°C. Since existing ring/liner materials cannot withstand these higher operating temperatures alternatives are needed for this critical tribological interface. This paper describes the development of a cost effective ID grinding technique for machining the bores of plasma sprayed diesel engine cylinder liners.
Technical Paper

Proton Exchange Membrane Fuel Cell Characterization for Electric Vehicle Applications

1994-03-01
940296
This paper presents experimental data and an analysis of a proton exchange membrane fuel cell system for electric vehicle applications. The dependence of the fuel cell system's performance on air stoichiometry, operating temperature, and reactant gas pressure was assessed in terms of the fuel cell's polarity and power density-efficiency graphs. All the experiments were performed by loading the fuel cell with resistive heater coils which could be controlled to provide a constant current or constant power load. System parasitic power requirements and individual cell voltage distribution were also determined as a function of the electrical load. It was found that the fuel cell's performance improved with increases in temperature, pressure and stoichiometry within the range in which the fuel cell was operational. Cell voltage imbalances increased with increases in current output.
Technical Paper

A 2-D Computational Model Describing the Flow and Filtration Characteristics of a Ceramic Diesel Particulate Trap

1998-02-23
980545
A 2-D computational model was developed to describe the flow and filtration processes, in a honeycomb structured ceramic diesel particulate trap. This model describes the steady state trap loading, as well as the transient behavior of the flow and filtration processes. The theoretical model includes the effect of a copper fuel additive on trap loading and transient operation. The convective terms were based on a 2-D analytical flow field solution derived from the conservation of mass and momentum equations. The filtration theory incorporated in the time dependent numerical code included the diffusion, inertia, and direct interception mechanisms. Based on a measured upstream particle size distribution, using the filtration theory, the downstream particle size distribution was calculated. The theoretical filtration efficiency, based on particle size distribution, agreed very well (within 1%) with experimental data for a number of different cases.
Technical Paper

A 2-D Computational Model Describing the Heat Transfer, Reaction Kinetics and Regeneration Characteristics of a Ceramic Diesel Particulate Trap

1998-02-23
980546
A 2-D CFD model was developed to describe the heat transfer, and reaction kinetics in a honeycomb structured ceramic diesel particulate trap. This model describes the steady state as well as the transient behavior of the flow and heat transfer during the trap regeneration processes. The trap temperature profile was determined by numerically solving the 2-D unsteady energy equation including the convective, heat conduction and viscous dissipation terms. The convective terms were based on a 2-D analytical flow field solution derived from the conservation of mass and momentum equations (Opris, 1997). The reaction kinetics were described using a discretized first order Arrhenius function. The 2-D term describing the reaction kinetics and particulate matter conservation of mass was added to the energy equation as a source term in order to represent the particulate matter oxidation. The filtration model describes the particulate matter accumulation in the trap.
Technical Paper

Frictional Performance Test for Transmission and Drive Train Oils

1991-02-01
910745
Lubricating oil affects the performance of friction materials in transmission, steering and brake systems. The TO-2 Test measured friction retention characteristics of lubricating oils used with sintered bronze friction discs. This paper introduces a new friction performance test for drive train lubricants that will be used to support Caterpillar's new transmission and drive train fluid requirements, TO-4, which measures static and dynamic friction, wear, and energy capacity for six friction materials, and replaces the TO-2 test. The new test device to be introduced is an oil cooled, single-faced clutch in the Link Engineering Co. M1158 Oil/Friction Test Machine.
Technical Paper

Diesel Engine Flame Photographs With High Pressure Injection

1988-02-01
880298
The effect of high pressure injection (using an accumulator type unit injector with peak injection pressure of approximately 20,000 psi, having a decreasing injection rate profile) on combustion was studied. Combustion results were obtained using a DDA Series 3–53 diesel engine with both conventional analysis techniques and high speed photography. Diesel No. 2 fuel and a low viscosity - high volatility fuel, similar to gasoline were used in the study. Results were compared against baseline data obtained with standard injectors. Some of the characteristics of high pressure injection used with Diesel No. 2 fuel include: substantially improved ignition, shorter ignition delay, and higher pressure rise. Under heavy load - high speed conditions, greater smokemeter readings were achieved with the high pressure injection system with Diesel No. 2 fuel. Higher flame speeds and hence, greater resistance to knock were observed with the high volatility low cetane fuel.
Technical Paper

Methanol vs. Natural Gas Vehicles: A Comparison of Resource Supply, Performance, Emissions, Fuel Storage, Safety, Costs, and Transitions.

1988-10-01
881656
This paper is a comprehensive comparative analysis of methanol, compressed natural gas, and liquefied natural gas as automotive fuels. First, we examine natural gas, coal, and biomass feedstocks, and the “security” of foreign feedstocks. Next, vehicle performance and emissions are considered, followed by an analysis of vehicle refuelling and storage technology. Environmental impacts of fuel production and distribution are analyzed; followed by a review of health, flammability, transport, and end-use hazards. We perform a detailed cost analysis that combines fuel cost and vehicle cost into discounted life-cycle cost-per-mile. Finally, we discuss the feasibility and implications of transitions to methanol and natural gas from our current vehicular fuel system. We find that natural gas vehicles may offer slight economic and environmental advantages, but that a transition to natural gas fuel would be more difficult, at least in the U.S.
Technical Paper

HEUI - A New Direction for Diesel Engine Fuel Systems

1993-03-01
930270
Caterpillar Inc. has developed a new diesel engine fuel system, powered by hydraulics and controlled electronically. This Hydraulic Electronic Unit Injector, (HEUI), requires no mechanical actuating or mechanical control devices, and offers many advantages over conventional fuel injection systems. Inherent features of the HEUI Fuel System include injection pressure control independent of engine load or speed, totally flexible injection timing, and full electronic control of injection parameters. Packaging the HEUI Fuel System on an engine is simple, as the injector is compact and available in a variety of configurations. The hydraulic actuating circuit is straightforward, using lubricating oil from the engine sump. Hydraulic lines may be internal to the engine or external. This paper describes the Caterpillar HEUI Fuel System, its operating features, performance advantages, and application to diesel engines.
Technical Paper

Engine Electronics Technology

1993-09-01
932404
Electronics technology has evolved significantly since the first electronically controlled heavy duty on-highway truck engines were introduced in the mid 1980's. Engine control hardware, software, and sensor designs have been driven by many factors. Emissions regulations, fuel economy, engine performance, operator features, fleet management information, diagnostics, vehicle integration, reliability, and new electronics technology are some of those factors. The latest engine electronics technology is not only found in heavy duty on-highway trucks, but in off-highway applications as well. Track-type tractors, haul trucks, wheel loaders, and agricultural tractors now benefit from the advantages of electronic engines. And, many more new applications are being developed.
Technical Paper

Emissions and Fuel Usage by the U. S. Truck and Bus Population and Strategies for Achieving Reductions

1974-02-01
740537
This paper presents an approach to modeling the United States truck and bus population. A detailed model is developed that utilizes domestic factory sales figures combined with a scrappage factor as a building block for the total population. Comparison with historical data for 1958-1970 shows that the model follows trends well for intermediate parameters such as total vehicle miles per year, total fuel consumption, scrappage, etc. Fuel consumption and HC, CO, NO2, CO2 and particulate matter emissions for gasoline and diesel engines are of primary interest. The model details these parameters for the time span 1958-2000 in one-year increments. For HC and CO, truck and bus emissions could equal or exceed automobile emissions in the early 1980s, depending on the degree of control. Three population control strategies are analyzed to determine their effects on reducing fuel consumption or air pollution in later years.
Technical Paper

A Turbocharged Spark Ignition Engine with Low Exhaust Emissions and Improved Fuel Economy

1973-02-01
730633
Turbocharging, in addition to increasing an engine's power output, can be effectively used to maintain exhaust emission levels while improving fuel economy. This paper presents the emission and performance results obtained from a turbocharged multicylinder spark ignition engine with thermal reactors and exhaust gas recirculation (EGR) operated at steady-state, part-load conditions for four engine speeds. When comparing a turbocharged engine to a larger displacement naturally aspirated engine of equal power output, the emissions expressed in grams per mile were relatively unchanged both with and without EGR. However, turbocharging provided an average of 20% improvement in fuel economy both with and without EGR. When comparing the turbocharged and nonturbocharged versions of the same engine without EGR at a given load and speed, turbocharging increased the hydrocarbon (HC) and carbon monoxide (CO) emissions and decreased oxides of nitrogen (NOx) emissions.
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