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In a Spark-Ignited engine, there will come a point, as load is increased, where the unburned air-fuel mixture undergoes auto-ignition (knock). The onset of knock represents the upper limit of engine output, and limits the extent of engine downsizing / boosting that can be implemented for a given application. Although effective at mitigating knock, requiring high octane fuel is not an option for most markets. Retarding spark timing can extend the high load limit incrementally, but is still bounded by limits for exhaust gas temperature, and spark retard results in a notable loss of efficiency. Likewise, enriching the air-fuel mixture also decreases efficiency, and has profound negative impacts on engine out emissions. In this current work, a Direct-Injected, Boosted, Spark-Ignited engine with Variable Valve Timing was tested under steady state high load operation. Comparisons were made among three fuels; an 87 AKI, a 91 AKI, and a 110 AKI off-road only race fuel.

Rear Window Buffeting (RWB) is the low-frequency, high amplitude, sound that occurs in many 4-door vehicles when driven 30-70 mph with one rear window lowered. The goal of this paper is to demonstrate that the mechanisms of RWB are similar to that of sun roof buffeting and to describe the results of several actions suspected in contributing to the severity of RWB. Finally, the results of several experiments are discussed that may lend insight into ways to reduce the severity of this event. A detailed examination of the side airflow patterns of a small Sport Utility Vehicle (SUV) shows these criteria exist on a small SUV, and experiments to modify the SUV airflow pattern to reduce RWB are performed with varying degrees of success. Based on the results of these experiments, design actions are recommended that may result in the reduction of RWB.

Impingement of jet-to-jet has been found to give improved spray penetration characteristics and higher vaporization rates when compared to multi-hole outwardly injecting fuel injectors which are commonly used in the gasoline engine. The current work studies a non-reacting spray by using a 5-hole impinging-jet style direct-injection injector. The jet-to-jet collision induced by the inwardly opening nozzles of the multi-hole injector produces rapid and short jet breakup which is fundamentally different from how conventional fuel injectors operate. A non-reacting spray study is performed using a 5-hole impinging jet injector and a traditional 6-hole Bosch Hochdruck-Einspritzventil (HDEV)-5 gasoline direct-injection (GDI) injector with gasoline as a fuel injected at 172 bar pressure with ambient temperature of 653 K and 490 K and ambient pressure of 37.4 bar and 12.4 bar.

Spray structure has a significant effect on emissions and performance of an internal combustion engine. The main objective of this study is to investigate spray structures based on four different multiple jet impingement injectors. These four different multiple jet-to-jet impingement injectors include 1). 4-hole injector (Case 1), which has symmetric inwardly opening nozzles; 2). 5-1-hole (Case 2); 3). 6-2-hole (Case 3); and 4). 7-3-hole (Case 4) which corresponding to 1, 2, 3 numbers of adjacent holes blocked in a 5-hole, 6-hole, and 7-hole symmetrical drill pattern, respectively. All these configurations are basically 4-holes but with different post collision spray structure. Computational Fluid Dynamics (CFD) work of these sprays has been performed using an Eulerian-Lagrangian modelling approach.

Suitable and effective nutrient delivery systems will be required for both long-duration studies of plant growth and for implementation of bioregenerative life support technologies involving crop production in closed micro-gravity environments. Such environments are anticipated onboard a Space Station. The development of such systems hinges on acquiring the scientific and engineering knowledge necessary to design for micro-gravity operations. We have completed the preliminary design of a flight experiment called the Nutrient Delivery Testbed-1 (NDT-1) which will provide a substantial amount of information about the behavior of such systems in the space environment. The NDT-1 package includes a computer control subsystem, two motor-driven nutrient solution reservoirs, a nutrient solution composition monitoring subsystem, a solution sampling subsystem, three different nutrient delivery systems, and a plant surrogate.

Regenerative life support is considered a key enabling technology for the human exploration of space. Without regeneration, the cost of supplying the materials necessary to sustain human life escalates so rapidly that manned space flight becomes uneconomical for all but short, near-Earth missions. One of the methods for providing regenerative life support utilizes a Controlled Ecological Life Support System, or CELSS. To accomplish this regeneration, the CELSS must incorporate technologies for food production, food processing, atmospheric revitalization, water purification, trace contaminant control, and waste processing. Many experiments have been conducted to characterize the performance of individual CELSS subsystems (e.g., plant growth, waste processing). However, very little research has been done to define the performance and operational aspects of CELSS technology at the overall system level.

Little information exists on the responses of plants to environmental conditions which combine lower than Earth-normal atmospheric pressures with changes in the partial pressures of oxygen, carbon dioxide, and nitrogen. Data collected on the growth of plants in such environments will be valuable in the development of low-pressure plant growth facilities for use on Space Station Freedom, the moon, and Mars. Such low pressure environments have been proposed previously as a means of facilitating EVA operations. Additionally, in some planetary base applications, the use of low atmospheric pressure would allow the use of lightweight plant growth structures for food production, thus reducing both the mass and the launch cost of the life support system.

The FAA and other Air Navigation Service Providers (ANSPs) plan to share the existing cockpit data radio for NextGen data communication applications. This radio is currently used for supporting airline operations. Sharing this radio, which operates in a relatively open network environment, with mission critical air traffic control communications creates a need to address air-ground security. Most of the data to be shared over air-ground communication is tactical and transient in nature. In addition, secure communication between the controller and the pilot provides situational awareness to all receivers listening on the voice radio channel. In this paper we provide a rationale for securing air-ground communication and explore some of the issues in implementing a secure air-ground communication channel between the controller and the pilot over the shared radio.

Today's advanced technology engines have a high content of electronic actuation requiring sophisticated real-time embedded software sensing and control. To enable research on such engines, a system with a flexible engine control unit (ECU) that can be rapidly configured and programmed is desired. Such a system is being used in the Advanced Internal Combustion Engine (AICE) Laboratories at Michigan Tech University (MTU) for research on a multi-cylinder spark-ignited gasoline, a high pressure common rail diesel and a single cylinder alternative fuels research engine. The system combines a production ECU with a software development system utilizing Mathworks Simulink/Stateflow © modeling tools. The interface in the Simulink modeling environment includes a library of modeling and interface blocks to the production Operating System (OS), Low Level Drivers (LLD) and CAN-based calibration tool.

This is the second part of a study on using port water injection to quantifiably enhance the knock performance of fuels. In the United States, the metric used to quantify the anti-knock performance of fuels is Anti Knock Index (AKI), which is the average of Research Octane Number (RON) and Motor Octane Number (MON). Fuels with higher AKI are expected to have better knock mitigating properties, enabling the engine to run closer to Maximum Brake Torque (MBT) spark timing in the knock limited region. The work done in part I of the study related increased knock tolerance due to water injection to increased fuel AKI, thus establishing an ‘effective AKI’ due to water injection. This paper builds upon the work done in part I of the study by repeating a part of the test matrix with Primary Reference Fuels (PRFs), with iso-octane (PRF100) as the reference fuel and lower PRFs used to match its performance with the help of port water injection.

High-speed spray-to-spray liquid impingement could be an effective phenomenon for the spray propagation and droplet vaporization. To achieve higher vaporization efficiency, impingement from two-hole nozzles is analyzed in this paper. This paper focuses on investigating vaporization mechanism as a function of the impingement location and the collision breakup process provided by two-hole impinging jet nozzles. CFD (Computational Fluid Dynamics) is adopted to do simulation. Lagrangian model is used to predict jet-to-jet impingement and droplet breakup conditions while KH-RT breakup and O'Rourke collision models are implemented for the simulation. The paper includes three parts: First, a single spray injected into an initially quiescent constant volume chamber using the Lagrangian approach is simulated to identify the breakup region, which will be considered as a reference to study two-hole impinging jet nozzles. Lagrangian simulation results would be validated via experimental results.

Anti-knock index (AKI) is a metric that can be used to quantify the anti-knock performance of a fuel and is the metric used in the United States. AKI is the average of Research Octane Number (RON) and Motor Octane Number (MON), which are calculated for every fuel on a Cooperative Fuel Research (CFR) engine under controlled conditions according to ASTM test procedures. Fuels with higher AKI have better knock mitigating properties and can be run with a combustion phasing closer to MBT in the knock limited operating region of a gasoline engine. However, fuels with higher AKI tend to be costlier and less environmentally friendly to produce. As an alternative, the anti-knock characteristics of lower AKI fuels can be improved with water injection. In this sense, the water injection increases the ‘effective AKI’ of the fuel.

Introducing water in a diesel engine has been known to decrease peak combustion temperatures and decrease NOx emissions. This however, has been limited to stationary and marine applications due to the requirement of a separate water supply tank in addition to the fuel tank, thereby a two-tank system. Combustion of hydrocarbon fuels produce between 1.35 (Diesel) and 2.55 times (Natural Gas) their mass in water. Techniques for extracting this water from the exhaust flow of an engine have been pursued by the United States department of defense (DOD) for quite some time, as they can potentially reduce the burden of supply of drinking water to front line troops in theater. Such a technology could also be of value to engine manufacturers as it could enable water injection for performance, efficiency and emissions benefits without the drawbacks of a two-tank system.

The application of accelerated testing theory is a difficult proposition, yet one that can result in considerable time and cost savings, as well as increasing a product's useful life. In Accelerated Testing: A Practitioner's Guide to Accelerated and Reliability Testing, readers are exposed to the latest, most practical knowledge available in this dynamic and important discipline. Authors Bryan Dodson and Harry Schwab draw on their considerable experience in the field to present comprehensive, insightful views in this book. Readers have free access to a website with numerous Excel templates and statistical tables as well as government documents and the AMSAA Reliability Growth Handbook. Development and quality assurance tests are defined in detail and are presented from a practical viewpoint. Included are testing fundamentals, plans and models, and equipment and methods most commonly used in accelerated testing.