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Despite numerous research efforts, there is no reliable and widely accepted tool for the prediction of erosion prone material surfaces due to collapse of cavitation bubbles. In the present paper an Erosion Aggressiveness Index (EAI) is proposed, based on the pressure loads which develop on the material surface and the material yield stress. EAI depends on parameters of the liquid quality and includes the fourth power of the maximum bubble radius and the bubble size number density distribution. Both the newly proposed EAI and the Cavitation Aggressiveness Index (CAI), which has been previously proposed by the authors based on the total derivative of pressure at locations of bubble collapse (DP/Dt>0, Dα/Dt<0), are computed for a cavitating flow orifice, for which experimental and numerical results on material erosion have been published. The predicted surface area prone to cavitation damage, as shown by the CAI and EAI indexes, is correlated with the experiments.

High-efficiency, clean-combustion strategies for heavy-duty diesel engines are critical for meeting stringent emissions regulations and reducing the costs of aftertreatment systems that are currently required to meet these regulations. Results from previous constant-volume combustion-vessel experiments using a single jet of fuel under quiescent conditions have shown that mixing-controlled soot-free combustion (i.e., combustion where soot is not produced) is possible with #2 diesel fuel. These experiments employed small injector-orifice diameters (≺ 150 μm) and high fuel-injection pressures (≻ 200 MPa) at top-dead-center (TDC) temperatures and densities that could be achievable in modern heavy-duty diesel engines.

NVH is gaining importance in the quality perception of off-highway machine performance and operator comfort. Booming noise, a low frequency NVH phenomenon, can be a significant sound issue in an off-highway machine. In order to increase operator comfort by decreasing the noise levels and noise annoyance, a tuned mass damper (TMD) was added to the resonating panel to suppress the booming. Operational deflection shapes (ODS) and experimental modal analysis (EMA) were performed to identify the resonating panels, a damper was tuned in the lab and on the machine to the specific frequency, machine operational tests were carried out to verify the effectiveness of the damper to deal with booming noise.

The bending fatigue performance of gears, cantilever beam specimens, and notched-axial specimens were evaluated and compared. Specimens were machined from a modified SAE-4118 steel, gas-carburized, direct-quenched and tempered. Bending fatigue specimens were characterized by light metallography to determine microstructure and prior austenite grain size, x-ray analysis for residual stress and retained austenite measurements, and scanning electron microscopy to evaluate fatigue crack initiation, propagation and overload. The case and core microstructures, prior austenite grain sizes and case hardness profiles from the various types of specimens were similar. Endurance limits were determined to be about 950 MPa for both the cantilever beam and notched-axial fatigue specimens, and 1310 MPa for the single gear tooth specimens.

The growth of auto sales in emerging markets provides a good opportunity for automakers. Cost is a key factor for any automaker to win in an emerging market. This paper analyzes risks and opportunities in a low cost manufacturing environment. The Chinese auto market is used as an example and three categories of risks are analyzed. A typical risk assessment for cost reduction includes the analysis of environment risks, process risks and strategic risks associated with all phases of a product life. In an emerging market, emission regulations are a rapidly-evolving environment variable, since most countries with less regulated emission codes try to catch up with the newly- developed technologies to meet sustainable growth targets. Emission regulations have a huge impact on product design, manufacturing and maintenance in the automotive industry, and hence the related cost reduction must be thoroughly analyzed during risk assessment.

With stringent emission regulations, many subsystems that abate engine tailpipe-out emissions become a necessary part for engines. The increased level of complexity poses technical challenges for the quality and reliability for modern engines. Among the spectrum of quality control methodologies, one conventional methodology focuses on every component's quality to ensure that the accumulative deviation is within predetermined limits. This conventional methodology tightens the component tolerance during the manufacturing process and typically results in increased cost. Another conventional methodology that is on the other side of the spectrum focuses on tailoring an engine calibration solution to offset the manufacturing differences. Although the tailored engine calibration solution reduces manufacturing cost for components, it increases the development and validation cost for engines. Given the cost and time constraints, system integration plays an important role in engine development.

Various engine platforms employ Selective Catalytic Reduction (SCR) technology to reduce the tail pipe emissions of oxides of nitrogen (NOx) from diesel engines as part of an overall strategy to comply with the emission regulations in place in various countries. High levels of NOx conversion (greater than 98%) in SCR aftertreatment may provide operating margin to increase overall fuel efficiency. However, to realize the potential fuel efficiency gains, the SCR technology employed should achieve high NOx conversion with limited reductant slip over transient application cycles in addition to steady state operation. A new approach to SCR controls was developed and implemented. This approach does not rely on any maps to determine the amount of urea solution to be dosed, thus significantly reducing calibration and development time and effort when implementing the SCR technology on multiple engine platforms and applications.

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.

This paper discusses a joint customer-supplier program intended to further develop the ability to design and apply aluminum alloy pistons selectively reinforced with ceramic fibers for heavy duty diesel engines. The approach begins with a comprehensive mechanical properties evaluation of base and reinforced material. The results demonstrated significant fatigue strength improvement due to fiber reinforcement, specially at temperatures greater than 300°C. A simplified numerical analysis is performed to predict the temperature and fatigue factor values at the combustion bowl area for conventional and reinforced aluminum piston designs for a 6.6 liter engine. It concludes that reinforced piston have a life expectation longer than conventional aluminum piston. Structural engine tests under severe conditions of specific power and peak cylinder pressure were used to confirm the results of the cyclic properties evaluation and numerical analysis.

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.

Field testing of an extended life coolant technology in Class 8 trucks, equipped with Caterpillar C-12 engines revealed excellent coolant life with negligible inhibitor depletion to 400,000 miles with no refortification and no coolant top-off. In separate evaluations in Caterpillar 3406E equipped trucks, extended corrosion protection and component durability were established out to 700,000 miles, without the need for refortification other than top-off.

The Society of Automotive Engineers Fatigue Design & Evaluation Committee [SAE FD&E] is actively working on a total life project for weldments, in which the welding residual stress is a key contributor to an accurate assessment of fatigue life. Physics-based welding process simulation and various types of residual stress measurements were pursued to provide a representation of the residual stress field at the failure location in the fatigue samples. A well-controlled and documented robotic welding process was used for all sample fabrications to provide accurate inputs for the welding simulations. One destructive (contour method) residual stress measurement and several non-destructive residual stress measurements-surface X-ray diffraction (XRD), energy dispersive X-ray diffraction (EDXRD), and neutron diffraction (ND)-were performed on the same or similarly welded samples.

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 groups worldwide have been actively developing specifications and requirements for biodegradable hydraulic fluids for mobile applications. These groups have recognized that an industry-wide specification is necessary due to the increase in environmental awareness in the agriculture, construction, forestry, and mining industries, and to the increasing number of local regulations primarily throughout Europe. Caterpillar has responded to this need by publishing a requirement, Caterpillar BF-1, that may be used by Caterpillar dealers, customers, and industry to help select high-performance biodegradable hydraulic fluids. This requirement was written with the input of several organizations that are known to be involved with the development of similar types of specifications and requirements.

It is estimated that operating continuously on a B20 fuel containing the current allowable ASTM specification limits for metal impurities in biodiesel could result in a doubling of ash exposure relative to lube-oil-derived ash. The purpose of this study was to determine if a fuel containing metals at the ASTM limits could cause adverse impacts on the performance and durability of diesel emission control systems. An accelerated durability test method was developed to determine the potential impact of these biodiesel impurities. The test program included engine testing with multiple DPF substrate types as well as DOC and SCR catalysts. The results showed no significant degradation in the thermo-mechanical properties of cordierite, aluminum titanate, or silicon carbide DPFs after exposure to 150,000 mile equivalent biodiesel ash and thermal aging. However, exposure of a cordierite DPF to 435,000 mile equivalent aging resulted in a 69% decrease in the thermal shock resistance parameter.

The induction hardening process involves a complex interaction of electromagnetic heating, rapid cooling, metallurgical phase transformations, and mechanical behavior. Many factors including induction coil design, power, frequency, scanning velocity, workpiece geometry, material chemistry, and quench severity determine a process outcome. This paper demonstrates an effective application of a numerical analysis tool for understanding of induction hardening. First, an overview of the Caterpillar induction simulation tool is briefly discussed. Then, several important features of the model development are examined. Finally, two examples illustrating the use of the computer simulation tool for solving induction-hardening problems related to cracking and distortion are presented. These examples demonstrate the tool's ability to simulate changes in process parameters and latitude of modeling steel or cast iron.

Since the advent of P/M technology as a near net shape production process, millions of mechanical components of various shapes and sizes have been produced. Although P/M continues to be one of the fast growing shaping processes, it suffers from the inability to produce intricate geometry's such as internal tapers, threads or recesses perpendicular to pressing direction. In such cases application of machining as a secondary forming operation becomes the preferred alternative. However, machining of P/M parts due to their inherent porosity is known to decrease tool life and increase tool chatter and vibration. Consequently, several attempts have been made to improve the machinability of P/M materials by either addition of machinability enhancing elements such as sulfur, calcium, tellurium, selenium, etc., or by resin impregnation of P/M parts.

Smaller locomotives often use mechanical transmissions instead of diesel-electric drive systems typically used in larger locomotives. This paper discusses how Model Based Design was used to develop the complete drive train control system for a 24 ton sugar cane locomotive. A complete MATLAB Simulink machine model was built to fully test and verify the shift control logic, traction control, vehicle speed limiting, and braking control for this locomotive application before it was commissioned. The model included the engine, torque converter, planetary transmission, drive line, and steel on steel driving surface. Simulation was used to debug all control code and test and refine control strategies so that the initial field commissioning in remote Australia was executed very quickly with minimal engineering support required.

With stringent emission regulations, aftertreatment systems with a Diesel Particulate Filter (DPF) and a Selective Catalytic Reduction (SCR) are required for diesel engines to meet PM and NOx emissions. The adoption of aftertreatment increases the back pressure on a typical diesel engine and makes engine calibration a complicated process, requiring thousands of steady state testing points to optimize engine performance. When configuring an engine to meet Tier IV final emission regulations in the USA or corresponding Stage IV emission regulations in Europe, this high back pressure dramatically impacts transient performance. The peak NOx, smoke and exhaust temperature during a diesel engine transient cycle, such as the Non-Road Transient Cycle (NRTC) defined by the US Environmental Protection Agency (EPA), will in turn affect the performance of the aftertreatment system and the tailpipe emissions level.

A number of oxidation catalysts have been prepared using different types of advanced support materials such as ceria-zirconia, silica-titania, spinels and perovskites. Active metals such as Pd and Au-Pd were loaded by conventional impregnation techniques and/or deposition-precipitation methods. A liquid hydrocarbon delivery system was designed and implemented for the catalyst test benches in order to simulate the diesel engine exhaust environment. The activity of fresh (no degreening) catalysts was evaluated with traditional CO and light hydrocarbons (C2H4, C3H6) as well as with heavy hydrocarbons such as C10 H22.