Search Results

With more stringent emissions regulations, effective emission modeling on NOx and soot for both on-road and off-road diesel engines becomes increasingly important for diesel engine system design and real-time engine controls. In this paper, a heuristic macro-parameter-dependent approach is proposed by combining theoretical analysis with semi-empirical method. The proposed modeling approach is different from the existing methods, such as empirical modeling, phenomenological modeling, and three-dimensional KIVA modeling. The proposed model uses the macro parameters of engine performance, both cycle-average (e.g., air-to-fuel ratio, EGR rate) and in-cylinder instantaneous data (e.g., cylinder pressure trace) as input. The model computes NOx and soot as a function of crank angle. A concept of “time-variant virtual space zones (burning, burned, and unburned)” is proposed based on the fraction of fuel burnt.

Hydraulic power steering systems traditionally are sized in a straightforward manner with easily verifiable results. The source of power in conventional systems is an engine driven pump that is effectively a source of hydraulic flow. As energy consumption of auxiliary functions becomes significant, on-demand power sources are considered. Best typified by hydraulic pumps driven by electric motors, these on-demand sources are often power limited, and established sizing practices should be re-visited.

This paper presents comparative analyses of steering wheel responses of various layouts for heavy goods vehicles, including rigid and articulated configurations. Newton and Lagrange techniques have been adopted to formulate and verify the generalized linear model for multi-axle rigid and articulated vehicles. The model is then used to simulate, analyze and compare steering angle response of a variety of commercially available vehicles. The study includes the analyses of steady state response and dynamic behavior for different layouts in terms of axle positions, number of axles and multiple steered axles.

The cost of human natural language translation of Service Information, Assembly Instructions, Training Materials, Operator Manuals and other similar documents is a major expense for manufacturers. One translation avoidance method involves replacing most of a document’s text with still and/or animated graphics. While the graphics with minimum text concept has savings potential, clarity of communication must be maintained for widespread application of this technique. The necessary clarity should be achieved if standards are established for the symbols and graphical conventions used. This paper provides an example of a repair procedure documented using the graphics with minimum text paradigm, describes many of the anticipated standards and provides an update on the progress towards achieving a standard development project.

Flax oil is the main goal of growing flaxseed. Flax oil has been used for nutrition, food, paint binder, putty, and wood finish. However, synthetic resin from flax oil has not been developed. In this paper we will develop a biopolymer derived from flax oil and the goal is to use it as a resin to produce a viable, biodegradable composite using natural fiber as reinforcement. First, the functionalization of the triglyceride group of the flax oil fatty acids with polymerizable chemical groups was studied. The triglyceride molecule of flax oil was epoxidized by the reaction of double bonds in the fatty acid with a peroxy acid (formic acid) to get epoxidized oil; the epoxidized oil was then reacted with ethylenically substituted carboxylic acid (acrylic acid) to form acrylated epoxidized flax oil. Polymer resins were prepared from flax oil by blending acrylated epoxidized flax oil with styrene and a free radical initiator.

Hybrid drivetrain systems are becoming increasingly prevalent in Automotive and Commercial Vehicle applications and have also been introduced for the 2009 Formula1 motorsport season. The F1 development has the clear intent of directing technical development in motorsport to impact the key issue of fuel efficiency in mainstream vehicles. In order to promote all technical developments, the type of system (electrical, mechanical, hydraulic, etc) for the F1 application has not been specified. A significant outcome of this action is renewed interest and development of mechanical hybrid systems comprising a high speed composite flywheel and a full-toroidal traction drive Continuously Variable Transmission (CVT). A flywheel based mechanical hybrid has few system components, low system costs, low weight and dispenses with the energy state changes of electrical systems producing a highly efficient and power dense hybrid system.

The main classification of Electric Parking Brakes (EPB) can be made into cable puller and caliper integrated types. In this paper, the main design considerations that need to be made for each type of system will be examined. In terms of mechanical design, actuator design factors including target capacity, system size, and vehicle mounting will be briefly discussed. In terms of software, a unified software structure that can incorporate both types of EPBs will be introduced. This unified approach, made up of fixed and variable modules, allows for more efficient software development for both types of EPB systems. The fixed modules are related to the identical target functions regardless of EPB type, while the variable modules are made up of the different considerations that need to be made depending on the EPB type in order to meet such targets. Finally, some test results of target functions for both types of EPB systems will be given.

Recently invented solutions (Canadian Patent 2593305 and United States Patent Applications 20090015008 and 20070194567) incorporate sphere-to-cone type of the interaction between sealing surfaces in a brake tube connector. An interaction of sphere-to-cone type has numerous advantages over one with a cone-to-cone type which is currently utilized in conventional automotive brake tube connectors. Incorporation of a sphere-to-cone interaction between the sealing surfaces dramatically improves connector's sealing robustness. Sphere-to-cone based connectors are resilient to the tube and seat axes misalignment. Correspondingly, sphere-to-cone based connectors have less variation of the securing torque and virtually no propensity to locked misalignment occurrence. The article analyzes another fundamental advantage of a sphere-to-cone mating over the conventional cone-to-cone one.

Piezoelectric self-sensing allows to measure frequency response functions of dynamical systems with one single piezoelectric element. This piezoceramics is used as actuator and sensor simultaneously. In this study, a model-based piezoelectric self-sensing technique is presented to obtain potential squealing frequencies of an automotive disc brake. The frequency-response function of the brake system is obtained during operation by measuring the current flowing through the piezoelectric element while the piezoelectric element is driven by a harmonic voltage signal with constant amplitude. The current flow is composed of the part which is required to drive the piezoelectric element as an actuator and a second part which is the sensor signal that is proportional to the vibration amplitude of the attached mechanical system. Typically the first part is dominant and the influence of the mechanical system is marginal.

Many engineers have been working to reduce brake noise in many ways for a long time. So far, a progress has been made in preventing and predicting brake noise. Nevertheless, there are some discrepancies of brake noise generation propensity between testing for the prototype and the production. As known in general, the reason for this unpredicted brake noise occurrence in production is partly due to the variation of the resonant frequency, material and the other unpredictable or unmanageable variations of the components in a brake system. In this paper, effects of chemical components and casting process of gray iron brake disc on its resonant frequency variation have been studied. Especially this paper is focused on the variation in material aspects and manufacturing parameters during disc casting in usual production condition. And their effects are investigated by the variation of out-of-plane modal resonant frequency.

Brake judder is about oscillations excited by brake application, which are generated in the contact area between brake pad and brake disc and are transmitted by the elements of the suspension to body and steering system. The driver perceives these perturbations as brake pedal pulsations, steering wheel rotational and body vibrations. The evaluation of a suspension concerning brake judder often takes place for the first time in road tests, since established simulation processes with a high significance concerning ride comfort are missing. At such a late moment necessary modifications in the development process are only hardly possible and very expensive. For avoiding brake judder a systematic development process is needed for brake and suspension. Each one can separately be improved in measurably borders so that their assembly is free of cold brake judder. The present paper shows appropriate test and simulation methods to achieve this.

Predominant brake noise evaluation and rating was developed many years ago and no longer fulfills the need of modern development work. An extended description of a noisy brake event (European expert group guideline EKB 3006) and a standardized test data exchange format, allowing the comparison of different source test results (EKB 3008) are presented. Today's noise rating systems are described and compared by selected examples. The paper proposes an open 4 level noise rating system (EKB 3007). It starts with simple occurrence statistics, noise rating based on sound levels, situational noise rating including duration and finally based on the human perception, described by psychoacoustics.

Permanent magnet AC generators are robust, inexpensive, and efficient compared to wound-field synchronous generators with brushless exciters. Their application in variable-speed applications is made difficult by the variation of the stator voltage with shaft speed. This paper presents the use of stator-side reactive power injection as a means of regulating the stator voltage. Design-oriented analysis of machine performance for this mode of operation identifies an appropriate level of machine saliency that enables excellent terminal voltage regulation over a specified speed and load range, while minimizing stator current requirements. This paper demonstrates that the incorporation of saliency into the permanent magnet generator can significantly reduce the size of the reactive current source that is required to regulate the stator voltage during operation over a wide range of speeds and loads.

During braking, third-body flows and layers govern friction mechanisms, which are fully responsible of the friction coefficient and wear. In the context of development of brake friction pairs, the involved tribological circuit has to be well understood and mastered. This paper concerns a sintered metal matrix composite used for TGV very high speed train. A series of low-energy stop brakings allows a detailed study of the third-body formation at the pad-disc contact. The pin surface is observed after each test. The evolution of the rubbing-area expansion all along the series is explained, and the friction behaviour, typical of the studied friction material, is related to the formation of a well-established third body at the pad-disc interface.

The system dependency analysis for complex aircraft systems is a model-based methodology and tool for analyzing availability and minimum acceptable control requirements for failures or event scenarios to support the aircraft and system safety analyses (SAE ARP4761) required to show compliance to 14CFR/CS §25.1309, §25.671 and other, related requirements. Aspects of the system such as functional interaction and dependencies to supply systems, physical items (equipment, wiring and tubing) and installation aspects are included in the analysis. This paper describes additional steps to enable the search for potential common cause failure conditions for the system of interest or airplane level systems based on the system model. Common cause analysis (CCA) procedures using the system dependency analysis rely on a systematic and checklist-based approach to determine potential common cause failure conditions.

The system dependency analysis for complex aircraft systems is a model-based methodology and tool for analyzing availability and minimum acceptable control requirements for failures or event scenarios to support the aircraft and system safety analyses (SAE ARP4761) required to show compliance to 14CFR/CS §25.1309, §25.671 and others. Aspects of the system such as functional interaction and dependencies to supply systems, physical items (equipment, wiring and tubing) and installation aspects are included in the analysis. The SAE paper “System Dependency Analysis for Complex Aircraft Systems” (2007-01-3852) describes the modeling approach and the analysis of system dependencies supporting the aircraft and system safety analyses. This paper provides examples for using the system dependency analysis to support the common cause analyses (SAE ARP4761) for complex aircraft systems.

Scope of the DRESS project is to research, develop and validate a distributed and redundant electrical steering system technology for an aircraft nose landing gear. The new system aims to: • reduce system weight at aircraft level, replacing the current hydraulic actuation system with an electric one. • improve aircraft safety, achieving higher system redundancy levels compared to the current technology capabilities. This paper presents an outline of different activities occurring in the DRESS project and also shows preliminary results of the new system performance.

The effectiveness of serial link articulated robots in aerospace drilling and fastening is largely limited by positional accuracy. Unguided production robotic systems are practically limited to +/-0.5mm, whereas the majority of aerospace applications call for tolerances in the +/-0.25mm range. The precision with which holes are placed on an aircraft structure is affected by two main criteria; the volumetric accuracy of the positioner, and how the system is affected when an external load is applied. Production use and testing of off-the-shelf robots has highlighted the major contributor to reduced stiffness and accuracy as being error ahead of the joint position feedback such as backlash and belt stretch. These factors affect the omni-directional repeatability, thus limiting accuracy, and also contribute to deflection of the tool point when process forces are applied.

The paper explains the compact fixturing based on magneto-rheological (MR) fluids that have been designed and validated for aeronautic stringers milling. The MR fluid based tooling developed is flexible and reconfigurable as it can be adapted to different profile's lengths and sections and it is able to fix compliant workpieces without reference faces as the MR fluid adapts to the outer shape of each profile. The MR fluid based tooling is suitable to hold non-magnetic materials such as aluminum and also materials that do not admit high clamping forces, such as titanium, because they will appear as deformation after machining due to the memory effect of titanium. The MR fluid based tooling has been tested in a machine environment under real machining conditions and promising results have been obtained.

A diesel particulate filter (DPF) controls and maintains a constant pressure drop across the filter by repeating the regeneration process for PM (Particulate Matter). However, the regeneration results in ash accumulation on the DPF. Although this ash accumulation is very slow, it eventually causes increased pressure drop which affects the product life of the DPF. Metal elements in the lubricant additives in the engine oil are the source of the ash. Since ash is an oxidized substance, the amount of ash produced depends on such factors as the amount of oil consumed in the engine and the kinds of lubricant additives contained in engine oil. According to the reference literature [1-3], ash accumulates on a DPF differently depending on use of either a passive regeneration system or an active regeneration system. With the passive regeneration system, ash accumulates uniformly on the filter wall while ash accumulates near the outlet of the filter with the active regeneration system.