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High pressure diesel sprays were visualized under vaporizing and combusting conditions in a constant-volume combustion vessel. Near-simultaneous visualization of vapor and liquid phase fuel distribution were acquired using a hybrid shadowgraph/Mie-scattering imaging setup. This imaging technique used two pulsed LED's operating in an alternative manner to provide proper light sources for both shadowgraph and Mie scattering. In addition, combustion cases under the same ambient conditions were visualized through high-speed combustion luminosity measurement. Two single-hole diesel injectors with same nozzle diameters (100μm) but different k-factors (k0 and k1.5) were tested in this study. Detailed analysis based on spray penetration rate curves, rate of injection measurements, combustion indicators and 1D model comparison have been performed.

Low-temperature combustion of diesel fuel was studied in a heavy-duty, single-cylinder, optical engine employing a 15-hole, dual-row, narrow-included-angle nozzle (10 holes × 70° and 5 holes × 35°) with 103-μm-diameter orifices. This nozzle configuration provided the spray targeting necessary to contain the direct-injected diesel fuel within the piston bowl for injection timings as early as 70° before top dead center. Spray-visualization movies, acquired using a high-speed camera, show that impingement of liquid fuel on the piston surface can result when the in-cylinder temperature and density at the time of injection are sufficiently low. Seven single- and two-parameter sweeps around a 4.82-bar gross indicated mean effective pressure load point were performed to map the sensitivity of the combustion and emissions to variations in injection timing, injection pressure, equivalence ratio, simulated exhaust-gas recirculation, intake temperature, intake boost pressure, and load.

An iterative learning control (ILC) algorithm has been developed for a test cell electro-hydraulic, fully flexible valve actuation system to track valve lift profile under steady-state and transient operation. A dynamic model of the plant was obtained from experimental data to design and verify the ILC algorithm. The ILC is implemented in a prototype controller. The learned control input for two different lift profiles can be used for engine transient tests. Simulation and bench test are conducted to verify the effectiveness and robustness of this approach. The simple structure of the ILC in implementation and low cost in computation are other crucial factors to recommend the ILC. It does not totally depend on the system model during the design procedure. Therefore, it has relatively higher robustness to perturbation and modeling errors than other control methods for repetitive tasks.

The objective of this study was to identify and gain an understanding of the origins of noise in a commercial excavator cab. This paper presents the results of two different tests that were used to characterize the vibration and acoustic characteristics of the excavator cab. The first test was done in an effort to characterize the vibration properties of the cab panels and their associated contribution to the noise level inside the cab. The second set, of tests, was designed to address the contribution of the external airborne noise produced by the engine and hydraulic pump to the overall interior noise. This paper describes the test procedures used to obtain the data for the signature analysis, operational deflection shapes (ODS), and sound diagnosis analysis. It also contains a discussion of the analysis results and an inside look into the possible contributors of key frequencies to the interior noise in the excavator cab.

Since the advent of P/M technology as a near net shape production process, millions of mechanical components of various shapes and sizes have been produced. Although P/M continues to be one of the fast growing shaping processes, it suffers from the inability to produce intricate geometry's such as internal tapers, threads or recesses perpendicular to pressing direction. In such cases application of machining as a secondary forming operation becomes the preferred alternative. However, machining of P/M parts due to their inherent porosity is known to decrease tool life and increase tool chatter and vibration. Consequently, several attempts have been made to improve the machinability of P/M materials by either addition of machinability enhancing elements such as sulfur, calcium, tellurium, selenium, etc., or by resin impregnation of P/M parts.

The favorable physical properties of hydrogen (H2) make it an excellent alternative fuel for internal combustion (IC) engines and hence it is widely regarded as the energy carrier of the future. Hydrogen direct injection provides multiple degrees of freedom for engine optimization and influencing the in-cylinder combustion processes. This paper compares the results in the mixture formation and combustion behavior of a hydrogen direct-injected single-cylinder research engine using two different injector locations as well as various injector nozzle designs. For this study the research engine was equipped with a specially designed cylinder head that allows accommodating a hydrogen injector in a side location between the intake valves as well as in the center location adjacent to the spark plug.

Optimal fuel injection strategies are obtained with a micro-genetic algorithm and an adaptive gradient method for a nonroad, medium-speed DI diesel engine equipped with a multi-orifice, asynchronous fuel injection system. The gradient optimization utilizes a fast-converging backtracking algorithm and an adaptive cost function which is based on the penalty method, where the penalty coefficient is increased after every line search. The micro-genetic algorithm uses parameter combinations of the best two individuals in each generation until a local convergence is achieved, and then generates a random population to continue the global search. The optimizations have been performed for a two pulse fuel injection strategy where the optimization parameters are the injection timings and the nozzle orifice diameters.

Past experiments have shown that numerous micro-hole sprays in close proximity produce drop sizes that are sensitive to the nozzle arrangement. Numerical studies have been performed to identify the interaction mechanisms between closely spaced sprays. It is shown that nozzle configurations can lower the drop-gas relative velocity and droplet Weber number, leading to reduced atomization intensity. However, the collisions involving droplets from neighboring sprays have a much greater effect on droplet size. Thus, neighboring sprays primarily interfere with each other through droplet collision.

Increasingly, the exchanges of data in complex ECM (Electronic Control Module) systems rely on multiple communication networks across various physical and network layers. This has greatly increased system flexibility and provided an excellent medium to create well-defined exchangeable interfaces between components; however this added flexibility comes with increased network complexity. A system-level approach allows for the optimization of data exchange and network configuration as well as the development of a comprehensive network failure strategy. Many current ECM systems utilize complex multi-network communication strategies to exchange and control data to components. Recently, Caterpillar implemented an HIL (Hardware-In-the-Loop) test system that provides an approach for developing and testing a comprehensive ECM network strategy.

As concerns over air pollution continue to increase, all vehicles are subject to greater scrutiny for their emissions levels. Snowmobiles and other off-road recreational vehicles are now required to meet emissions regulations enacted by the United States Environmental Protection Agency (EPA). Currently these vehicles are certified using a stationary test procedure with the engine operating attached to a dynamometer and following a five-mode test cycle. The five modes range from idle to wide open throttle and are chosen to represent the typical operation regime of a vehicle. In addition, the EPA five-mode stationary emissions test has been traditionally used for scoring competition snowmobiles at the SAE Clean Snowmobile Challenge (CSC). For the 2009 CSC, in-service emission testing was added to the competition to score the teams on actual, in-use emissions during operation of their competition snowmobile operated on a controlled test course.

The effects of an oxidation catalytic converter (OCC), an emulsified fuel, and their combined effects on particle number and volume concentrations compared to those obtained when using a basefuel were studied. Particle size and particulate emission measurements were conducted at three operating conditions; idle (850 rpm, 35 Nm), Mode 11 (1900 rpm, 277 Nm) and Mode 9 (1900 rpm, 831 Nm) of the EPA 13 mode cycle. The individual effects of the emulsified fuel and the OCC as well as their combined effects on particle number and volume concentrations were studied at two different particle size ranges; the nuclei (less than or equal to 50 nm) and accumulation (greater than 50 nm) modes. An OCC loaded with 10 g/ft3 platinum metal (OCC1) and a 20% emulsified fuel were used for this study and a notable influence on the particle size with respect to number and volume distributions was observed.

This paper summarizes the successful application of Computational Fluid Dynamics (CFD) analysis to predict and control the cavitation erosion in a hydraulic control valve. The accurate control of different vehicle operations demands very fine spool modulations in a hydraulic valve. The precise spool modulations create very high flow rates and high-pressure drops in the valve. The low local fluid pressure regions create cavitation inside the valve. Due to the explosion of bubbles there is a high erosion damage to the valve body as well as the spool surface. The CFD analysis has been used to predict the location of cavitation origination and also used to control the cavitation by redistributing the flow inside the valve.

The effectiveness of three different techniques, designed to improve the bending fatigue life in comparison to conventionally processed gas-carburized 8620 steel, were evaluated with modified Brugger bending fatigue specimens and actual ring and pinion gears. The bending fatigue samples were machined from forged gear blanks from the same lot of material used for the pinion gear tests, and all processing of laboratory samples and gears was done together. Fatigue data were obtained on standard as-carburized parts and after three special processing histories: shot-peening to increase surface residual stresses; double heat treating to refined austenite grain size; and vacuum carburizing to minimize intergranular oxidation. Standard room-temperature S-N curves and endurance limits were obtained with the laboratory samples. The pinions were run as part of a complete gear set on a laboratory dynamometer and data were obtained at two imposed torque levels.

Non-evaporating diesel sprays have been simulated utilizing the ETAB and the WAVE atomization and breakup models and have been compared with experimental data. The experimental penetrations and widths were determined from back-lit spray images and the droplet sizes have been measured by means of a Malvern particle sizer. The model evaluation criteria include the spray penetration, the spray width and the local droplet size. The comparisons have been performed for variations of the injection pressure, the gas density and the fuel viscosity. The fuel nozzle exit velocities used in the simulations have been computed with a special code that considers the effect of in-nozzle cavitation. The simulations showed good overall agreement with experimental data. However, the capabilities of the models to predict the droplet size for different fuels could be improved.

Measurement of internal combustion engine air flow is challenging due to the required modification of the intake system and subsequent change in the air flow pattern. In this paper, various surge tank volumes were investigated to improve the accuracy of measuring air flow rate into a 674-cm3, four-stroke, liquid-cooled, internal combustion engine. According to the experimental results, when the venturi meter is used to measure the intake air flow rate, an air surge tank is required to be installed downstream of the venturi to smoothen the air flow. Moreover, test results revealed that increasing air surge tank volume beyond a limit could have a negative effect on the engine performance parameters especially in carbureted engines where controlling AFR is difficult. Although the air flow rate into the engine changed with increasing tank volume, the air-fuel ratio was leaner for smaller tank volumes.

Diesel combustion and emissions formation is largely spray and mixing controlled and hence understanding spray parameters, specifically vaporization, is key to determine the impact of fuel injector operation and nozzle design on combustion and emissions. In this study, an eight-hole common rail piezoelectric injector was tested in an optically accessible constant volume combustion vessel at charge gas conditions typical of full load boosted engine operation. Liquid penetration of the eight sprays was determined via processing of images acquired from Mie back scattering under vaporizing conditions by injecting into a charge gas at elevated temperature with 0% oxygen. Conditions investigated included a charge temperature sweep of 800 to 1300 K and injection pressure sweep of 1034 to 2000 bar at a constant charge density of 34.8 kg/m₃.

The U.S. Renewable Fuel Standard (RFS2) requires an increase in the use of advanced biofuels up to 36 billion gallons by 2022. Longer chain alcohols, in addition to cellulosic ethanol and synthetic biofuels, could be used to meet this demand while adhering to the RFS2 corn-based ethanol limitation. Higher carbon number alcohols can be utilized to improve the energy content, knock resistance, and/or petroleum displacement of gasoline-alcohol blends compared to traditional ethanol blends such as E10 while maintaining desired and regulated fuel properties. Part I of this paper focuses on the development of scenarios by which to compare higher alcohol fuel blends to traditional ethanol blends. It also details the implementation of fuel property prediction methods adapted from literature. Possible combinations of eight alcohols mixed with a gasoline blendstock were calculated and the properties of the theoretical fuel blends were predicted.

With stringent emission regulations, aftertreatment systems with a Diesel Particulate Filter (DPF) and a Selective Catalytic Reduction (SCR) are required for diesel engines to meet PM and NOx emissions. The adoption of aftertreatment increases the back pressure on a typical diesel engine and makes engine calibration a complicated process, requiring thousands of steady state testing points to optimize engine performance. When configuring an engine to meet Tier IV final emission regulations in the USA or corresponding Stage IV emission regulations in Europe, this high back pressure dramatically impacts transient performance. The peak NOx, smoke and exhaust temperature during a diesel engine transient cycle, such as the Non-Road Transient Cycle (NRTC) defined by the US Environmental Protection Agency (EPA), will in turn affect the performance of the aftertreatment system and the tailpipe emissions level.

The effects of fuel sulfur concentration on heavy-duty diesel emissions have been studied at two EPA steady-state operating conditions, mode 9 (1900 RPM, 75% Load) and mode 11(1900 RPM, 25% Load). Data were obtained using one fuel at two sulfur levels (Low Sulfur, LS = 0.01 wt% S and Doped Low Sulfur DS = 0.29 wt% S). All tests were conducted using a Cummins LTA10-300 heavy-duty diesel engine. No significant changes were found for the nitrogen oxides (NOx), soluble organic fractions (SOF) and XAD-2 (a copolymer of styrene and divinylbenzene) organic component (XOC) due to the fuel sulfur level increase at either engine mode. The hydrocarbon (HC) levels were not significantly affected by sulfur at mode 9; however, at mode 11 the HC levels were reduced by 16%. The total particulate matter (TPM) levels increased by 17% at mode 11 and by 24% at mode 9 (both significantly different).

Punch-stretch tests to determine formability of type 304 stainless steel sheet were conducted using a hemispherical dome test. Sheets of 19.1 mm width and 177.8 mm width were stretched on a 101.6 mm diameter punch at punch rates between 0.042 to 2.12 mm/sec with three lubricant systems: a mineral seal oil, thin polytetrafluoroethelyne sheet with mineral seal oil, and silicone rubber with mineral seal oil. The resulting strain distributions were measured and the amount of martensite was determined by magnetic means. Increasing lubricity resulted in more uniform strain distributions while increased punch rates tended to decrease both strain and transformation distributions. High forming limit values were related to the formation of high and uniformly distributed martensite volume fractions during deformation. The results of this study are interpreted with an analysis of the effects of strain and temperature on strain induced martensite formation in metastable austenitic stainless steels.