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Continuously variable transmissions, commonly known as CVT's, have been shown to be feasible alternatives to the conventional multi-step gear transmissions (standard or automatic) typically used in automotive applications. Most CVT applications, however, rely on a shaft-to-shaft transmission arrangement, in which the belt-sheave action limits the load capacity of the transmission, particularly at the high power ranges (low speed, high torque). In this paper, a system based on a combined planetary gear train and a continuously variable pulley system is presented. The uniqueness of this arrangement is that the variable pulleys provide a power/torque split and recirculation function, which, when combined with the planetary gear train function, produces a continuously variable power split transmission system.

A bi-fuel engine with the ability to run optimally on both compressed natural gas (CNG) and gasoline is being developed. Such bi-fuel automotive engines are necessary to bridge the gap between gasoline and natural gas as an alternative fuel while natural gas fueling stations are not yet common enough to make a dedicated natural gas vehicle practical. As an example of modern progressive engine design, a Saturn 1.9 liter 4-cylinder dual overhead cam (DOHC) engine has been selected as a base powerplant for this development. Many previous natural gas conversions have made compromises in engine control strategies, including mapped open-loop methods, or resorting to translating the signals to or from the original controller. The engine control system described here, however, employs adaptive closed-loop control, optimizing fuel delivery and spark timing for both fuels.

A family of transmission systems based on a “Planetary Gear - CVT” mechanism is presented here. The systems considered consist of two compound planetary gear trains connected through a CVT pulley system to provide the power/torque split and recirculation function, without the use of additional clutches and/or chain drives. A two degree of freedom system results in which one of the degrees of freedom is directly related to the CVT ratio. The mechanisms considered here combine the gear reduction function of compound planetary gear trains with the continuously variable trans- used as a circulating power control unit. The kinematics and dynamics of this family of systems is presented with emphasis on the belt forces, torques on the various shafts and the overall input/output velocity ratios through the CVT ratio span. Then a parametric analysis is conducted to characterize the effect of the various functional ratios and parameters of the system in terms of the overall performance.

This paper describes the strategy for engineering design, modeling, and analysis of a planetary - CVT (Continuously Variable Transmission) system. The uniqueness of this mechanism arrangement resides in the combination of features associated to two conventional systems, namely a planetary gear train and a CVT pulley system, acting as a power circulation control unit. The pulley system features a manually activated control over the variable pitch ratios of the CVT, by means of which the overall system input/output velocity and power ratios can be controlled according the operational requirements. By using the belt drive as a feedback control unit (as opposed to the main driveline), one of the major problems or limitations of conventional CVT arrangements is overcome, namely the belt capacity of the system. Specifically, the output torque obtained through the planetary output shaft is greater than the torque circulating through the pulleys.

In this study a higher-order shear deformable, analytical model is developed to analyze composite shells with parametric modeling capabilities. The material and geometric properties and loading conditions can be varied as parameters which satisfy a set of constraints to allow the designer to achieve a sensible and computationally feasible FE model. The formulation is derived with equal emphasis on all the six strain as well as stress components at a generic point in the shell laminate. Unlike many other available models which violates the equilibrium conditions at lamina interfaces, this model satisfies the equilibrium conditions at the lamina interfaces for a certain class (angle-ply and unidirectional orthotropic) of laminates.

The objective of this study was to evaluate iso-butanol (C4H9OH) as an alternative fuel for spark ignition engines. Unlike methanol (CH3OH) and ethanol (C2H5OH), iso-butanol has not been extensively studied in the past as either a fuel blend candidate with gasoline or straight fuel. The performance of a single cylinder engine (ASTM=CFR) was studied using alcohol-gasoline blends under different input parameters. The engine operating conditions were: three carburetor settings (three different fuel flow rates), spark timings of 5°, 10°, 15°, 20°, and 25° BTDC, and a range of compression ratios from a minimum of 7.5 to a maximum of 15 in steps of one depending on knock. The fuels tested were alcohol-gasoline blends having 5%, 10%, 15%, and 20% of iso-butanol, ethanol, and methanol. And also as a baseline fuel, pure gasoline (93 ON) was used. The engine was run at a constant speed of 800 RPM.

A mathematical model has been developed to transfer Chassis Dynamometer (CD) test cycles for heavy duty vehicles to the equivalent Engine Dynamometer (ED) test cycles. The model assumed a generalized drivetrain layout, and a variable drive line efficiency. An interactive computer code was written to represent the mathematical model for different drivetrain systems. Several CD test cycles were used to obtain equivalent ED test cycles for a sample based upon an urban bus equipped with an automatic transmission. Results showed the possibility of simulating CD test cycles with equivalent ED test cycles for heavy-duty urban buses under certain assumptions.

In the case of advanced light weight material applications, the design of such components, in many cases, are based on applied surface tractions These surface loads can be caused by various means. When wind effects are present these tractions can be due to pressure, suction or drag. In the case of underwater applications, hydrostatic pressure and friction caused by moving against water current needs to be considered in the design. These are some of the traction load applications, a design engineer has to deal with in his advanced material applications. In contrast to the conventional materials, the modern structures made of highly directional dependent material properties, respond the applied loads and environment in an unpredicted way, so that, a detail analysis and design is always necessary. Hence in the present study a higher-order shear deformation formulation is developed to calculate the distribution of stresses accurately in angle-ply laminated shells of revolution.

Spray modeling techniques have evolved from the classic DDM (Discrete Drops Method) approach, where the continuous liquid jet is discretized into “drops” or “parcels” till advanced spray models often based on Eulerian approaches. The former technique, although computationally efficient, is essentially inadequate in highly dense jets, as in the near nozzle region of compression ignition engines, while the latter could lead to extreme levels of computational effort when resolved interface capturing methods, such as VoF (Volume of Fluids) and LS (Level-Set) types, are used. However, in a typical engineering calculation, the mesh resolution is considerably coarser than in these high fidelity computations. If one presumes that these interfacial details are far smaller than the mesh size, smoothing features over at least one cell ultimately results in a diffuse-interface treatment in a Eulerian framework.

In the present paper the results of an experimental and numerical analysis of a common-rail, high pressure Diesel spray evolving in high counter pressure conditions is reported. The experimental study was carried out mainly in terms of spray momentum flux indirect measurement by the spray impact method; the measurement of the impact force time-histories, along with the CFD analysis of the same phenomenon, gave interesting insight in the internal spray structure. As well known, the overall spray structure momentum flux along with the injection rate measurements can be used to derive significant details about the in-nozzle flow and cavitation phenomena intensity. The same global spray momentum and momentum flux measurement can be useful in determining the jet-to-jet un-uniformities also in transient, engine-typical injection conditions which can assist in the matching process between the injection system and the combustion chamber design.

Corona discharge from a RF quarter wave coaxial cavity resonator is considered as a plasma ignition source for spark ignited (SI) internal combustion (IC) engines. The gaseous discharge processes associated with this device are analyzed using principles of gas kinetics and gaseous electronics, with assumed values for the electric field strength. Corona discharge occurs when the electric field shaped and concentrated by a single electrode exceeds the breakdown potential of the surrounding gas. Ambient electrons, naturally present due to ionizing radiation, drift in the direction of the externally applied field, gaining energy while undergoing elastic collisions with neutral molecules. After gaining sufficient energy they dissociate, excite, or ionize the neutral particles through inelastic collision, creating additional electrons. This process leads to avalanche electrical breakdown of the gas within about 10-8 sec.

Radio Frequency Corona ignition systems represent an interesting solution among innovative ignition strategies for their ability to stabilize the combustion and to extend the engine operating range. The corona discharge, generated by a strong electric field at a frequency of about 1 MHz, produces the ignition of the air-fuel mixture in multiple spots, characterized by a large volume when compared to a conventional spark, increasing the early flame growth speed. The transient plasma generated by the discharge, by means of thermal, kinetic and transport effects, allows a robust initialization of the combustion even in critical conditions, such as using diluted or lean mixtures. In this work the effects of Corona ignition have been analyzed on a single cylinder optical engine fueled with gasoline, comparing the results with those of a traditional single spark ignition.

The aim of the paper is the comparison of the injection process with different fuels, i.e. a standard diesel fuel and a pure biodiesel. Multiphase cavitating flows inside diesel nozzles are analyzed by means of unsteady CFD simulations using a two-fluid approach with consideration of bubble dynamics, on moving grids from needle opening to closure. Two five-hole nozzles with cylindrical and conical holes are studied and their behaviors are discussed taking into account the different properties of the two fuels. Extent of cavitation regions is not much affected by the fuel type. Biodiesel leads to significantly higher mass flow only if the nozzle design induces significant cavitation which extends up to the outlet section and if the injector needle is at high lift. If the internal hole shaping is able to suppress cavitation, the stabilized mass flows are very similar with both fuels.

The problems which arise during the design of a motorcycle, may affect the proper functioning of the vehicle, and ride comfort. This type of problem is particularly found in sport where mechanical components which can cause malfunctioning should, be replaced quickly within a very limited time. This work is an investigation of the swingarm component. The aim is to link objective data such as stiffness and natural frequencies (derived through the application of scientific method) with subjective information such as handling and comfort perceived by professional riders. The testers were two riders of the 2008 World SuperBike Championship. They were chosen to represent two kinds of driving behaviors: one of them had a affable riding attitude, whereas, the second was more aggressive. Three motorcycle swingarms used in the 2008 World SuperBike Championship, were mechanically characterized: FEM and experimental investigations were performed.

In the last decades, worldwide automotive regulations induced the industry to dramatically increase the application of electronics in the control of the engine and of the pollutant emissions reduction systems. Besides the need of engine control, suitable fault diagnosis tools had also to be developed, in order to fulfil OBD-II and E-OBD requirements. At present, one of the problems in the development of Diesel engines is represented by the achievement of an ever more sharp control on the systems used for the pollutant emission reduction. In particular, as far as NOx gas is concerned, EGR systems are mature and widely used, but an ever higher efficiency in terms of emissions abatement, requires to determine as better as possible the actual oxygen content in the charge at the engine intake manifold, also in dynamic conditions, i.e. in transient engine operation.

Water injection in highly boosted gasoline direct injection (GDI) engines has become an attractive area over the last few years as a way of increasing efficiency, enhancing performance and reducing emissions. The technology and its effects are not new, but current gasoline engine trends for passenger vehicles have several motivations for adopting this technology today. Water injection enables higher compression ratios, optimal spark timing and elimination of fuel enrichment at high load, and possibly replacement of EGR. Physically, water reduces charge temperature by evaporation, dilutes combustion, and varies the specific heat ratio of the working fluid, with complex effects. Several of these mutually intertwined aspects are investigated in this paper through computational fluid dynamics (CFD) simulations, focusing on a turbo-charged GDI engine with port water injection (PWI). Different strategies for water injection timing, pressure and spray targeting are investigated.

It has been proposed that an automated remote color inspection of automobile body panels is possible with a reasonably precise color measurement. This paper outlines a test of a new 3D color measurement technology as applied to this task and presents the results of the first test. A camera is set up several feet away from a car body; a 3D orientation measuring system takes both 3D and color data from the car. The raw data is presented as a set of 3D graphs; the geometry-corrected data is also provided. Statistical analysis is presented to indicate system precision.

The Rand Cam engine is a novel design which avoids the use of pistons in favor of a cavity of varying size and shape. A set of vanes protrudes from a rotor into a circular trough in a stator. The vanes seal to the walls and base of the trough, which is of varying depth, and progress around the trough with rotation of the rotor. These vanes therefore pass through the rotor and are constrained to move parallel to the rotational axis. Intake and exhaust processes occur through ports in the stator wall which are revealed by the passing vanes. Advantages of the basic design include an absence of valves, reduction in reciprocating masses, presence of an integral flywheel in the rotor and strong fluid movement akin a swirl induced by the relative velocity between the rotor and stator.

Emission legislation for passenger cars is requiring a drastic reduction of exhaust pollutants from internal combustion engines (ICE). In this framework, achieving a quick heating-up of the catalyst is of paramount importance to cut down the cold start emissions and meet future regulation requirements. This paper describes the development and the basic characteristics of a novel burner for gasoline engines exhaust systems designed for being activated immediately at engine cold start. The burner is comprised of a fuel injector, an air system, and an ignition device. The design of the combustion chamber is first presented, with a description of the air-fuel interactions and mixture formation processes. Swirl is used along with a flame-holder concept to anchor the flame at the mixer exit. Spray-swirl and spray-walls interaction are also discussed. Computational Fluid Dynamics (CFD) analyses have been used to investigate these aspects.

Natural gas (NG) is an alternative fuel for spark-ignition engines. In addition to its cleaner combustion, recent breakthroughs in drilling technologies increased its availability and lowered its cost. NG consists of mostly methane, but it also contains heavier hydrocarbons and inert diluents, the levels of which vary substantially with geographical source, time of the year and treatments applied during production or transportation. To investigate the effects of NG composition on engine performance and emissions, a 3D CFD model of a heavy-duty diesel engine retrofitted to NG spark ignition simulated lean-combustion engine operation at low speed and medium load conditions. The work investigated three NG blends with similar lower heating value (i.e., similar energy density) but different Methane Number (MN). The results indicated that a lower MN increased flame propagation speed and thus increased in-cylinder pressure and indicated mean effective pressure.