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A computational methodology has been developed for loss prediction in intake regions of internal combustion engines. The methodology consists of a hierarchy of four major tasks: (1) proper computational modeling of flow physics; (2) exact geometry and high quality and generation; (3) discretization schemes for low numerical viscosity; and (4) higher order turbulence modeling. Only when these four tasks are dealt with properly will a computational simulation yield consistently accurate results. This methodology, which is has been successfully tested and validated against benchmark quality data for a wide variety of complex 2-D and 3-D laminar and turbulent flow situations, is applied here to a loss prediction problem from industry. Total pressure losses in the intake region (inlet duct, manifold, plenum, ports, valves, and cylinder) of a Caterpillar diesel engine are predicted computationally and compared to experimental data.

Virtual Product Development (VPD) is a key enabler in CAE and depends upon accurate implementation of multibody dynamics. This paper discusses the formulation and implementation of a large-scale multibody dynamics simulation code. In the presented formulation, the joint variables are used as the generalized coordinates and spatial algebra is used to formulate the system equations of motion. Although the presented formulation utilizes the joint variables as the generalized coordinates, closed-loop mechanisms can be easily modeled using impeded constraints. Baumgart stabilization approach is used to eliminate the constraint violations without using the expensive Newton-Raphson iterations. Integrated rigid and flexible body dynamic simulation allows accurate prediction of structural loads, stress, and strains. Both modal and nodal flexible body approaches are discussed in the paper.

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.

Most pieces of mobile equipment (machines) produce an audible signal to indicate movement in the rearward direction. This signal is intended to alert nearby personnel of the potential danger associated with the machine moving in a direction where the operator may not be able to see people or objects in the machine path. Anyone who has been on or near a construction site recognizes the familiar “beep…beep…beep…” of this signal as the backup alarm. To be effective, the backup alarm must be discernible, timely, and relevant to those people where a reaction is intended. As machine designers respond to various sound directives for reducing sound emissions (including the backup alarm), the performance of the backup alarm is receiving special attention. An emerging solution is an alarm capable of sensing ambient sounds and producing an audible signal proportional to the sensed sound levels-a self-adjusting backup alarm.

There is an ongoing interest in biodegradable hydraulic fluids. Biodegradable fluids are often considered to include only vegetable oils, polyol esters and diester base stocks. However, other fluid base stocks including highly refined mineral oils, poly(alpha olefins) and fire-resistant fluids such as water-glycol hydraulic fluids are also biodegradable fluid alternatives. This paper will provide an overview of the international literature on biodegradable fluids, various international testing protocol, fluid base stocks, effect of oxidative stability, material compatibility and pump performance.

Today’s business climate and economy demand new, innovative strategies from the initial kickoff of research and development - to the mining of ore from the earth - to the final inspection of a finished product in a mid-western factory. From startup companies with two employees to the largest companies, the world faces new and challenging requirements every day. The demands from companies, customers, executives, and shareholders continue to drive for higher outputs with more efficient use of personnel and investments. Fortunately, the rate of technology continues to exponentially accelerate, which allows those at the cutting edge of technology to capitalize. Caterpillar has been a pioneer in advanced technology since its inception and has been developing the foundation for autonomy over the past four decades.

This paper identifies potential performance benefits and computational costs of applying advanced multivariable control theory concepts to coordinate the control of a general multi-degree-of-freedom fuel system. The control variables are injection duration and pressure. The focus is on the design of a robust multi-input multi-output controller using H-infinity and mu synthesis methodology to coordinate the control of injection duration and pressure; reduce overshoots and system sensitivity to parameter variations caused by component aging. Model reduction techniques are used to reduce the order of the H-infinity controller to make it practically implementable. Computer simulation is used to test the robust performance of a generic engine and fuel system model controlled by the reduced order H-infinity controller and a traditional proportional plus integral controller.

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.

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.

Ducted fuel injection (DFI), a concept that utilizes fuel injection through ducts, was implemented in a constant pressure High Temperature Pressure Vessel at 60 bar ambient pressure, 800-1000 K ambient temperature, and 21 % oxygen. The ducts were 14 mm long and placed 3-4.7 mm from the orifice exit. The duct diameters ranged from 1.6-3.2 mm and had a rounded inlet and a tapered outlet. Diesel fuel was used in single-orifice fuel injectors operating at 250 MPa rail pressure. The objective of this work was to study soot reduction for various combinations of orifice and duct diameters. A complete data set was taken using the 150 μm orifice. A smaller data set was acquired for a 219 μm orifice, showing similar trends. Soot reduction peaked at an optimal duct diameter of 2-2.25 mm, corresponding to an 85-90 % spray area reduction for the 150 μm orifice. Smaller or larger duct diameters were less effective. Duct diameter had a minimal effect on ignition delay.

Testing of ducted fuel injection (DFI) in a single-cylinder engine with production-like hardware previously showed that adding a duct structure increased soot emissions at the full load, rated speed operating point [1]. The authors hypothesized that the DFI flame, which travels faster than a conventional diesel combustion (CDC) flame, and has a shorter distance to travel, was being re-entrained into the on-going fuel injection around the lift-off length (LOL), thus reducing air entrainment into the on-going injection. The engine operating condition and the engine combustion chamber geometry were duplicated in a constant pressure vessel. The experimental setup used a 3D piston section combined with a glass fire deck allowing for a comparison between a CDC flame and a DFI flame via high-speed imaging. CH* imaging of the 3D piston profile view clearly confirmed the re-entrainment hypothesis presented in the previous engine work.

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.

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 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.

NVH is gaining importance in the quality perception of off-highway machines' performance and operator comfort. Booming noise, a low frequency NVH phenomenon, can be a significant sound issue in a motor grader when it is used under certain operating conditions that cause low frequency excitations to the machine. In order to increase operator comfort by decreasing the noise levels and noise annoyance, both simulation and testing techniques were leveraged to reduce the booming noise of a motor grader. Simultaneous structural/acoustics simulations and experimental modal tests were performed to evaluate this phenomenon. The simulation models were validated using test results and then used to evaluate solutions to this noise problem. Further field tests confirmed the validity of these recommended solutions.

An improved method for studying mixing-controlled compression ignition (MCCI) flame interactions with an engine combustion chamber has been developed. It is implemented in a constant pressure vessel, which contains a portion of a piston and a portion of a cylinder head, where the cylinder head is emulated by a transparent fused silica window. This method allows for vaporizing or combusting fuel jets to be imaged from two orthogonal directions. The piston and cylinder head can be adjusted to emulate in-engine piston positions from top dead center (TDC) to approximately 15 mm away from TDC. The design allows for pistons from engine bore sizes up to approximately 175 mm to be studied, including the ability to simulate injector spray included angles from 120°-180°. In this study, the piston was made as an extruded piston bowl profile, where the length of the extrusion approximated the arc length between two neighboring jets from a 6-hole injector.

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.

During the early 1990s, the Track-Type Tractors Division (TTTD) of Caterpillar Inc. experienced several challenges. The Division faced increasing global competition in the midst of an economic recession. Although intense plant modernization and reorganization occurred in the five previous years, the business unit was not profitable. In 1993, Track-Type Tractors Division instituted its solution -- a change in its culture. Previously, the culture hindered the division’s ability to move forward. This was revealed in a 1992 review detailing the major obstacles inhibiting management from achieving divisional goals. The division leaders recognized that a change in business philosophy, as opposed to further plant modernization, was required to achieve production goals and stay globally competitive.

This paper details results of a numerical and experimental investigation into the relative performance of vaned and vaneless mixed flow turbines for application to medium and heavy-duty diesel engines utilizing pulse exhaust systems. Previous investigations into the impact of nozzle vanes on turbine performance considered only open turbine housings, whereas a majority of medium and heavy-duty diesel engine applications are six-cylinder engines using pulse exhaust systems with divided turbines. The two turbine stages for this investigation were carefully designed to meet the constraints of engines with pulse exhaust systems and to control confounding factors that would undermine the vaned vs vaneless performance comparison. Detailed CFD analysis and turbine dynamometer test results confirm a significant efficiency advantage for the vaned turbine stage under both full and partial admission conditions.

The NOx reduction performance under lean conditions over γ-alumina was evaluated using a micro-reactor system and a non-thermal plasma-equipped bench test system. Various alumina samples were obtained from alumina manufacturers to assess commercial alumina materials. In addition, γ-alumina samples were synthesized at Caterpillar with a sol-gel technique in order to control alumina properties. The deNOx performances of the alumina samples were compared. The alumina samples were characterized with analytical techniques such as inductively coupled plasma (ICP) emission spectroscopy, temperature programmed desorption (TPD) and surface area measurements (BET) to understand physical and chemical properties. The information derived from these techniques was correlated with the NOx reduction performance to identify key parameters of γ-alumina for optimizing materials for lean-NOx and plasma assisted catalysis.