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This article presents basic separation mechanisms with coalescing/impinging separators studied as the add-on to current popular centrifugal designs. The coalescence and impingement of oil on wire mesh and wave-plates are visualized and tested to investigate the impact of geometry and flow conditions on oil separation efficiency. Re-entrainment phenomenon is explained based on the mass balance. Oil mist flow at the swashplate reciprocating compressor discharge is quantified by video processing method to provide detailed information of the oil droplets. The physics behind oil separator is illustrated by visualization and measurement in this study, which gives useful guidelines for oil separator design and operation. The flow visualization shows the details of oil passing through different oil separation structures. Videos are quantified to provide information like droplet size distribution and liquid volume fraction.

This paper discusses an advanced computer-based process simulation model to predict cutting forces and surface error (also referred to as the lack of cylindricity) for the cylinder boring process. The model takes into consideration several enhanced features including dual and multiple-cylinder boring, back-boring, boring in the presence of windows/cavities, etc.. The model makes use of a Finite Element product model and the cutting force process model to generate a surface error profile at any axial level in the cylinder bore. A design of experiment approach is employed to study the influence of various process variables on bore surface error. The enhanced process simulation model may be used as a valuable tool in enhancing the simultaneous engineering of products and manufacturing processes.

This paper describes the simulation model of a backhoe excavator. The model uses a prescribed motion cycle and the objective of the program is to determine the power requirements for each of the cylinders as well as the total engine power requirement. Most computer simulations are developed by expressing the differential equations of motion for the system being studied. The known force inputs to the system are applied and the time response of the system is then obtained by numerically integrating the governing differential equations. This paper on the other hand develops the reverse of this. Utilizing a prescribed geometry and trajectory cycle for a linkage system as the input, the program solves for the types of force inputs that are required to achieve that trajectory. With the time dependence of the trajectory known, the total power required and the power required of each cylinder is also evaluated. A typical excavator linkage is shown in Fig. 1.

The presence and distribution of liquid fuel within an engine cylinder at cold start may adversely affect the hydrocarbon emissions from port-injected, spark ignition engines. Therefore, high speed videos of the liquid fuel entry into the cylinder of an optical engine were recorded in order to assess the effect of various engine operating parameters on the amount of liquid fuel inducted into the cylinder, the sizes of liquid drops present and the distribution of the fuel within the cylinder. A 2.5L, V-6, port-injected, spark ignition engine was modified so that optical access is available throughout the entire volume of one of the cylinders. A fused silica cylinder is sandwiched between the separated block and head of the engine and a “Bowditch-type” piston extension is mounted to the production piston. The Bowditch piston has a fused silica crown so that visualization is possible through the top of the piston as well as through the transparent cylinder.

A geometrically accurate, three-dimensional finite element model of a Diesel engine exhaust valve and cylinder head assembly has been developed to analyze the effect of cylinder head interactions on exhaust valve stresses. Results indicate that a multi-lobed stress pattern occurs around the exhaust valve head due to cylinder head deformation, stiffness variations, and thermal asymmetry. Consequently, peak valve bending and hoop stresses from the three-dimensional model are 48% and 40% higher, respectively, than for the two-dimensional, axisymmetric model. These results indicate the degree of model complexity required for more accurate analyses of exhaust valve operating stresses.

This paper describes and discusses a computer model that can be used to predict the hydraulic pump requirements of an excavator necessary to meet the specified productivity levels for a given set of design conditions. The model predicts the hydraulic cylinder flow rates, pressures, and power necessary to sustain a given work cycle. The study compares the results from a simulation of the excavator with actual test data obtained from a test vehicle taken during a typical work cycle.

The operation of a small bore high speed direct injection (HSDI) engine with a MVCO injector is simulated by the KIVA 3V code, developed by Los Alamos National Laboratory. The MVCO injector extends the range of injection timings over conventional injectors and it extra flexibility in designing injection schemes. Combustion from very early injection is observed with MVCO injections but not with conventional injection. This improves the fuel economy of the engine in terms of lower ISFC. Even better efficiency can be achieved by using biodiesel, which may be due to extra oxygen in the fuel improving the combustion process. Biodiesel sees a longer ignition delay for the initial injection. It also exhibits a faster burning rate and shorter combustion duration. Biodiesel also lowered both NOx and soot emissions. This is consistent with the general observation for soot emissions.

In this work, an efficient and unified combustion model is introduced to simulate the flame propagation, diffusion-controlled combustion, and chemically-driven ignition in both SI and CI engine operation. The unified model is constructed upon a G-equation model which addresses the premixed flame propagation. The concept of the Livengood-Wu integral is used with tabulated ignition delay data to account for the chemical kinetics which is responsible for the spontaneous ignition of fuel-air mixture. A set of rigorously defined operations are used to couple the evolution of the G scalar field and the Livengood-Wu integral. The diffusion-controlled combustion is simulated equivalent to applying the Burke-Schumann limit. The combined model is tested in the simulation of the premixed SI combustion in a constant volume chamber, as well as the CI combustion in a conventional small bore diesel engine.

The formation of fuel film in the combustion cylinder affects the mixing process of the air and the fuel, and the process of the combustion propagation in engines. Some models of film evaporation have been developed to predict the evaporation behavior of the film, but rarely experimental results have been produced, especially when the temperature is high. In this study, the evaporation behavior of the film of different species of oil and their blends at different temperature are observed. The 45 μL films of isooctane, 1-propanol, 1-butanol, 1-pentanol, and their blends were placed on a quartz glass substrate in the closed temperature-controlled chamber. The shape change of the film during evaporation was monitored by a high-speed camera through the window of the chamber. First, the binary blends film of isooctane and one of the other three oils were evaporated at 30 °C, 50 °C, 70 °C and 90 °C.

An efficient multi-component fuel droplet vaporization model has been developed in this work using discrete approach. The precise modeling of droplet vaporization process is divided into two parts: vapor-phase and liquid-phase sub-models. Temporal evolution of flow inside the droplet is considered to describe the transient behavior introduced by the slow diffusion process. In order to account for the internal circulation motion, surface regression and finite diffusion without actually resolving the spatial governing equations within the liquid phase, a set of ordinary differential equations is applied to describe the evolution of the non-uniform distributions of universal diffusional variables, i.e. temperature and species mass fraction. The differences between the droplet surface and bulk mean states are modeled by constructing a quasi-1D frame; the effect of the internal circulations is taken into consideration by using the effective diffusivity rather than physical diffusivity.

Single-laser-shot measurements of the fuel/air ratio in the cylinder of a motored direct-injection natural gas (DING) engine were obtained using a dual-pump coherent anti-Stokes Raman scattering (CARS) technique capable of simultaneously probing N2 and CH4. The DING engine was modified for optical access and CARS was used to probe the region near the glow plug. Measurements were acquired at eight different probe volume locations with one crank angle degree resolution for injections starting at 30° and 20° BTDC. The CARS data clearly show the arrival of the fuel jet at the probe volume and, from traversing the probe volume, the location of the centerlines of two fuel jets in the vicinity of the glow plug. The CARS measurements also show large fluctuations in fuel concentration on a shot-to-shot basis indicating the presence of large-scale mixing structures within the fuel jets.

Cylinder head combustion chamber and piston temperatures and heat fluxes were measured in a 2.2 L 4 cylinder spark ignition engine. Measurements for the combustion chamber were made at wide open throttle conditions, 1400 rpm to 5000 rpm at 600 rpm increments, additional measurements were made on the combustion chamber at part throttle conditions at 3200 RPM. Piston temperature and heat flux measurements were made at WOT conditions from 1400 to 3200 RPM in 600 RPM increments. Average combustion chamber surface temperatures ranged from 130 deg. C to 248 deg. C, while peak combustion chamber surface temperatures ranged from 142 deg. C to 258 deg. C for WOT conditions. Peak heat flus at the surface for WOT conditions in the combustion chamber ranged from 1.2 MW/m2to 5.0 MW/m2. Central region heat fluxes were 2.3 to 2.8 times greater than those in the end gas regions of the combustion chamber.

The finite volume, three-dimensional, turbulent flow code ARIS-3D is applied to the study of the complex flow field through the inlet port and within the cylinder of a uniflow-scavenged engine. The multiblock domain decomposition technique is used to accommodate this complex geometry. In this technique, the domain is decomposed into two blocks, one block being the cylinder and the other being the inlet duct. The effects of inlet duct length, geometric port swirl angle, and number of ports on swirl generating capability are explored. Trade-offs between swirl level and inherent pressure drop can thus be identified, and inlet port design can be optimized.

Basket motion of a cotton picker during the unloading cycle can produce unstable conditions that result in overturning the machine. The potential for overturning increases while operating the machine on a side slope with the basket dumping on the down-hill side. In this paper the writers investigate the influence of tire ballast, wheel weights and operator control of the hydraulic cylinder on the dynamic stability of the machine during the unloading cycle while operating on a side slope. Operator control at the beginning of the unloading cycle and near the end of the cylinder stroke promotes stable operation of the machine on a side slope.

Product engineers and product planners are routinely faced with trade-off decisions involving the cost of adding a product feature or modifying an existing feature versus its added value to the customer. The purpose of this paper is to assess the use of a personal computer (PC) for surveying respondents' willingness to pay (WTP) for four options - two-tone color, 4x4 drive, sporty trim package, and extended cab -- available on the base 1997 Ford F-150 truck. The results show that the respondents' stated WTP reflected the value of the options as determined from their prices and fraction of sales.

Service loading histories have the same general character for an individual route and the magnitudes vary from driver to driver. Both the magnitude and character of the loading history change from route to route and a linear scaling of one loading history does not characterize the variability of usage over a wide range of operating conditions. In this paper a technique for measuring and extrapolating cumulative exceedance diagrams to quantify the distribution of service loading in a vehicle is described. Monte Carlo simulations are coupled with the local stress strain approach for fatigue to obtain distributions of service loading. Fatigue life estimates based on the original loading histories are compared to those obtained from statistical descriptions of exceedance diagrams.

The blow-by phenomenon is seldom acquainted with diesel engines, but for a small bore HSDI optical diesel engine, the effects are significant. A difference in peak pressure up to 25% can be observed near top-dead-center. To account for the pressure differences, a 0-D crevice flow model with a dynamic ring pack model was incorporated into the KIVA code to determine the amount of blow-by. The ring pack model will take into account the forces acting on the piston rings, the position of the piston rings, and the pressure located at each region of the crevice volume at every time step. The crevice flow model takes into consideration the flow through the circumferential gap, ring gap, and the ring side clearance. As a result, the cylinder mass, trapped mass in the crevice regions, and the blow-by values are known. Validation of the crevice model is accomplished by comparing the in-cylinder motoring pressure trace with the experimental motoring data.

Homogeneous Charge Compression Ignition (HCCI) combustion employing single main injection strategies in an optically accessible single cylinder small-bore High-Speed Direct Injection (HSDI) diesel engine equipped with a Bosch common-rail electronic fuel injection system was investigated in this work. In-cylinder pressure was taken to analyze the heat release process for different operating parameters. The whole cycle combustion process was visualized with a high-speed digital camera by imaging natural flame luminosity. The flame images taken from both the bottom of the optical piston and the side window were taken simultaneously using one camera to show three dimensional combustion events within the combustion chamber. The engine was operated under similar Top Dead Center (TDC) conditions to metal engines. Because the optical piston has a realistic geometry, the results presented are close to real metal engine operations.

The US Army uses a light tactical High-Mobility Multi-Purpose Wheeled Vehicle (HMMWV) which, due to the amount of armor added, requires air conditioning to keep its occupants comfortable. The current system uses R134a in a dual evaporator, remote-mounted condenser, engine-driven compressor system. This vehicle has been adapted to use an environmentally friendly refrigerant (carbon dioxide) to provide performance, efficiency, comfort and logistical benefits to the Army. The unusual thermal heat management issues and the fact that the vehicle is required to operate under extreme ambient conditions have made the project extremely challenging. This paper is a continuation of work presented at the SAE Alternate Refrigerants Symposium held in Phoenix last June [1].

A multicomponent fuel film vaporization model using continuous thermodynamics is developed for multidimensional spray and wall film modeling. The vaporization rate is evaluated using the turbulent boundary-layer assumption and a quasi-steady approximation. Third-order polynomials are used to model the fuel composition profiles and the temperature within the liquid phase in order to predict accurate surface properties that are important for evaluating the mass and moment vaporization rates and heat flux. By this approach, the governing equations for the film are reduced to a set of ordinary differential equations and thus offer a significant reduction in computational cost while maintaining adequate accuracy compared to solving the governing equations for the film directly.