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This paper presents the latest results for a new high efficiency clean diesel combustion system – Adaptive PCCI Combustion (a premixed charge compression ignition mixed-mode combustion) using a micro-variable circular orifice (MVCO) fuel injector. Key characteristics of the new combustion system such as low NOx and soot emissions, high fuel efficiency, increased engine torque are presented through KIVA simulation results. While early premixed charge compression ignition (PCCI) combustion reduces engine-out NOx and soot, it's limited to partial loads by known issues such as combustion control, high HC and CO, and high pressure rise rate, etc. Conventional combustion is well controlled diffusion combustion but comes with high NOx and soot. Leveraging the key merits of PCCI and conventional combustion in a practical engine is both meaningful and challenging.

Roll bars are currently a primary source of operator protection for recreational vehicles, for certain lawn and garden tractors and for small agricultural tractors. In this paper we describe a family of nonlinear models to predict the large deflection response of a roll bar due to yielding of the material. This yielding permits the structure to absorb energy. The stress-strain relationship employs a power law model. Subsequent calculation of the complementary energy stored in the structure and application of Castigliano's second theorem yield the deflection at the point of loading. To demonstrate the feasibility of this energy method in the simulation of testing of roll bars, we present numerical results for the side, vertical, and fore-aft loading cases. Results include the load-deflection response for each load case as well as the strain energy stored in the roll bar as it deforms.

ROPS-TEST is a newly developed, interactive, graphics program that may be used to simulate testing of roll bars. Cross-sections that it currently supports include solid rectangular, rectangular tubing, and circular tubing. ROPS-TEST can be used to simulate testing for crush, rear and side loading. Output from ROPS-TEST includes load-deflection and strain energy-deflection plots. ROPS-TEST does not replace actual testing of prototype roll bars. Rather it serves as a design tool to select the best design options for a particular application prior to actual testing of the prototype roll bars.

The influence of different combustion chamber configuration, intake temperature, and coolant temperature on HCCI combustion processes were investigated in a single-cylinder optical engine. Two-dimensional images of the chemiluminescence were captured using an intensified CCD camera in order to understand the spatial distribution of the combustion. N-heptane was used as the test fuel. Three combustion chamber geometries with different squish lip, salient, orthogonal, reentrant shape, referred as V-type, H-type, and A-type respectively, were used in this study. Intake temperature was set to 65°C and 95°C, while coolant temperature was set to 85°C. The experimental data consisting of the in-cylinder pressure, heat release rate, chemiluminescence images all indicated that the different combustion chamber geometries result in different turbulence intensity in the combustion chamber, and thus affect the auto-ignition timing, chemiluminescence intensity, and combustion processes.

Laser diagnostics of fuel sprays are often hampered by multiple scattering effects. Planar laser-induced exciplex fluorescence (PLIEF) and Mie scattering images of a spray are presented, and the effects of multiple signal scattering are explored. A hollow-cone spray is cut in half with a spray cutter, and then imaged from either side. In one set, signal passes through the spray to the camera (back-cut images), and in the other set it does not (front-cut images), showing the effect of passing the signal through the spray to the camera. The cut spray is characterized with a phase Doppler anemometer (PDA) and Sauter Mean Diameter (SMD) is seen to range from 10-30 μm. Operational guidelines for using the cutter are presented. It was determined that a film forms on the cutter face 3-5 ms after the start of injection (ASOI) depending on the cutter temperature. Stripped droplets from this film increase droplet concentration and SMD in the center of the spray if the cutter is used improperly.

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.

Cavitation plays a significant role in the spray characteristics and the subsequent mixing and combustion process in engines. Cavitation has beneficial effects on the development of the fuel sprays by improving injection velocity and promoting primary break-up. On the other hand, intense pressure peaks induced by the vapor collapse may lead to erosion damage and severe degradation of the injector performance. In the present paper, the transient cavitating flow in the injector-like geometry was investigated using the modified turbulence model and cavitation criterion. A local density correction was used in the Reynolds-averaged Navier-Stokes turbulence model to reduce the turbulent viscosity, which facilitates the cavitation development. The turbulent stress was also considered in the cavitation inception stage. The modified model is capable of reproducing the cavitating flow with an affordable computational cost.

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 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.

The ability to categorize, compare and segregate the roll dynamical behavior of various vehicles from one another is a subject of considerable research interest. A number of comparison paradigms have been developed (static stability index, roll couple methods, etc.), but all suffer from lack of robustness: results developed on the basis of a particular comparison metric are often not able to be generalized across vehicle lines and types, etc., or they simply do not segregate vehicles at all. In addition, most models do not describe vehicle dynamics in sufficient detail, and some contain no dynamics at all (e.g., static stability index = t/2h). In the present work, static stability index, a two-degree-of-freedom roll model and a three-degree-of-freedom roll and handling model were used to locate eigenvalues for a sample of 43 vehicles consisting of (1) passenger cars, (2) light trucks, (3) sport/utility vehicles and (4) minivans.

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.

Hydrogen fuel is a future energy to solve the problems of energy crisis and environmental pollution. Hydrogen internal combustion engines can combine the advantage of hydrogen without carbon pollution and the main basic structure of the traditional engines. However, the power of the port fuel injection hydrogen engines is smaller than the same volume gasoline engine because the hydrogen occupies the volume of the cylinder and reduces the air mass flow. The turbocharger can increase the power of hydrogen engines but also increase the NOx emission. Hence, a comprehensive controlling strategy to solve the contradiction of the power, BTE and NOx emission is important to improve the performance of hydrogen engines. This paper shows the controlling strategy for a four-stroke, 2.3L hydrogen engine with a turbocharger. The controlling strategy divides the operating conditions of the hydrogen engine into six parts according to the engine speeds and loads.

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.

The transporting of live cattle involves the use of Class 8 tractors and livestock semi-trailers for transportation from farms and feedlots to processing plants. This travel may include unimproved roads, local streets, two lane highways, as well as interstate highways. Typically, cattle are compartmentalized in a “double deck” fashion as it provides utility and comports with size and weight limits for commercial Class 8 vehicles. Concern has been expressed for the effect of cattle movement upon the dynamic performance of the loaded Class 8 tractor-livestock trailer assembly. Loading guidelines exist for cattle that attempt to prevent injury or debilitation during transit, and literature exists on the orientation and some kinematics of loaded cattle. Considerable literature exists on the effect of liquid slosh in tankers and swinging beef carcasses suspended from hooks in refrigerated van trailers on the dynamic response and roll stability of those vehicles.

The detailed mechanisms by which oxygenated diesel fuels reduce engine-out soot emissions are not well understood. The literature contains conflicting results as to whether a fuel's overall oxygen content is the only important parameter in determining its soot-reduction potential, or if oxygenate molecular structure or other variables also play significant roles. To begin to resolve this controversy, experiments were conducted at a 1200-rpm, moderate-load operating condition using a modern-technology, 4-stroke, heavy-duty DI diesel engine with optical access. Images of broadband natural luminosity (i.e., light emission without spectral filtering) from the combustion chamber, coupled with heat-release and efficiency analyses, are presented for three test-fuels. One test-fuel (denoted GE80) was oxygenated with tri-propylene glycol methyl ether; the second (denoted BM88) was oxygenated with di-butyl maleate. The overall oxygen contents of these two fuels were matched at 26% by weight.

A method for making value tradeoff decisions between fuel economy and acceleration performance is demonstrated. Attribute value as defined by the S-Model Theory of Quality [1,2] is measured for the attributes of fuel economy and acceleration performance through a vehicle driving clinic. Willingness-to-pay values are found for the attributes at several different levels. The willingness-to-pay values are then used to refine the empirical and economic value curves previously determined for those attributes.

A novel framework for intelligent design of engine systems is introduced. Existing models of engine components and processes are integrated into a multi-purpose, flexible configuration framework. Fundamental thermodynamic elements, including zero-dimensional control volumes, one-dimensional pulsating fluid lines, and continuous flow machines are identified as the constituting components of engine systems. Models of the behavior of these elements, with various degrees of thermodynamic resolution, have been implemented into the framework. The task of the engine designer is, thus, reduced into selecting appropriate thermodynamic elements to model his engine system based on his design objectives. The applicability of the present framework to a wide range of simulation problems is demonstrated.

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.

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.

The use of substances other than petroleum based fuels for power sources is not a new concept. Prior to the advent of petroleum fueled vehicles numerous other substances were used to create mobile sources of power. As the world's petroleum supply dwindles, alternative fuel sources are sought after to replace petroleum fuels. Many industries are particularly interested in the development of renewable fuel sources, or biologically derived fuel sources, which includes ethanol. The use of No. 2 diesel as well as many alternative fuels in compression ignition engines result in injector coking. Injector coking can severely limit engine performance by limiting the amount of fuel delivered to the combustion chamber and altering the spray pattern. Injector tip coking is also one of the most sensitive measures of diesel fuel quality [1]. A machine vision system was implemented to quantify injector coking accumulation when a compression ignition engine was fueled with oxydiesel.