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The fuel injection equipment (FIE) has always been paramount to the performance of the Diesel engine. Increasingly stringent emissions regulations have dictated that the FIE becomes more precise and sophisticated. The latest generation FIE is therefore less tolerant to deposit formation than its less finely engineered predecessors. However, the latest emissions regulations make it increasingly difficult for engine manufacturers to comply without the use of exhaust aftertreatment. This aftertreatment often relies on catalytic processes that can be impaired by non-CHON (carbon, hydrogen, oxygen and nitrogen) components within the fuel. Fuel producers have therefore also been obliged to make major changes to try and ensure that with the latest technology engines and aftertreatment systems the fuel is still fit for purpose. However, there has recently been a significant increase in the incidence of reported problems due to deposit build-up within vehicle fuel systems.

The increased severity and prevalence of insoluble deposits formed on fuel injectors in gasoline direct injection (GDI) engines precipitates negative environmental, economic and healthcare impacts. A necessary step in mitigating deposits is to unravel the molecular compositions of these complex layered materials. But very little molecular data has been acquired. Mass spectrometry shows promise but most techniques require the use of solvents, making them unsuited for analyzing insoluble deposits. Here, we apply the high mass-resolving power and in-situ analysis capabilities of 3D OrbitrapTM secondary ion mass spectrometry (3D OrbiSIMS) to characterize deposits formed on the external tip and internal needle from a GDI injector. This is the first application of the technique to study internal GDI deposits. Polycyclic aromatic hydrocarbons (PAHs) are present up to higher maximum masses in the external deposit.

Over the last decade, there has been an impetus in the automobile industry to develop new diesel injector systems, driven by a desire to reduce fuel consumption and proscribed by the requirement to fulfil legislation emissions. The modern common-rail diesel injector system has been developed by the industry to fulfil these aspirations, designed with ever-higher tolerances and pressures, which have led to concomitant increases in fuel temperatures after compression with reports of fuel temperatures of ~150°C at 1500-2500 bar. This engineering solution in combination with the introduction of Ultra Low Sulphur diesel fuel (ULSD) has been found to be highly sensitive to deposit formation both external injector deposits (EDID) and internal (IDID). The deposits have caused concerns for customers with poor spray patterns misfiring injector malfunction and failure, producing increased fuel consumption and emissions.

Studies of diesel system deposits continue to be the subject of interest and publications worldwide. The introduction of high pressure common rail systems resulting in high fuel temperatures in the system with the concomitant use of fuels of varying solubilizing ability (e.g. ULSD and FAME blends) have seen deposits formed at the tip of the injector and on various internal injector components. Though deposit control additives (DCAs) have been successfully deployed to mitigate the deposit formation, work is still required to understand the nature and composition of these deposits. The study of both tip and internal diesel injector deposits (IDID) has seen the development of a number of bench techniques in an attempt to mimic field injector deposits in the laboratory. One of the most used of these is the Jet Fuel Thermal Oxidation Tester or JFTOT (ASTM D3241).

The recent developments in diesel fuel injection equipment coupled with the moves in the US to using ULSD and biodiesel blends has seen an increase in the number of reports from both engine manufacturers and fleet operators regarding fuel system deposit formation issues. These deposits not only form on and within the fuel injectors but they also form elsewhere in the fuel system, due to fuel recirculation. These will eventually accumulate in the fuel filters. Historically, diesel fuel system deposits have been attributed to contamination of the fuel or the degradation of the fuel with age. Such age related degradation has been attributed to oxidation of the fuel via well documented pathways, although the initiation of this process is still poorly understood. Papers at recent SAE meetings in Florence, San Antonio, Rio de Janeiro, San Diego and Kyoto have addressed many of these causes.

Traditionally, diesel fuel injection equipment (FIE) has frequently relied on the diesel fuel to lubricate the moving parts. When ultra low sulphur diesel fuel was first introduced into some European markets in the early 1980's it rapidly became apparent that the process of removing the sulphur also removed other components that had bestowed the lubricating properties of the diesel fuel. Diesel fuel pump failures became prevalent. The fuel additive industry responded quickly and diesel fuel lubricity additives were introduced to the market. The fuel, additive and FIE industries expended much time and effort to develop test methods and standards to try and ensure this problem was not repeated. Despite this, there have recently been reports of fuel reaching the end user with lubricating performance below the accepted standards.

Since 2009, there has been a rise in deposits of various types found in diesel fuel injection systems. They have been identified in the filter, the injector tip and recently inside the injector. The latter internal diesel injector deposits (IDIDs) have been the subject of a number of recent publications, and are the subject of investigations by CRC (Central Research Council Diesel Performance Group-Deposit Panel Bench/ Rig Investigation sub panel) in the US and CEN (Committee European de Normalisation TC19/WG24 Injector Deposit Task Force) and CEC (Coordinating European Council TDFG-110 engine test) in Europe. In the literature one of the internal injector deposit types, amide lacquers, has been associated with a poorly characterised noncommercial low molecular weight polyisobutylene succinimide detergent which also lacked provenance.

Experimental investigations of intake and exhaust valve timing effects at part load have been carried out on a 4 cylinder, 1.6 l spark ignition engine. The effects of valve timing on charge dilution by residual gases, and on fuel consumption and emission characteristics, have been explored. The valve timings, and particularly the duration of the valve overlap period, strongly influence levels of charge dilution. The extent to which this accounts for the observed changes in specific fuel consumption and emissions with valve timings is investigated. Residuals gas fraction values have been determined at various steady operating conditions through the analysis of gas samples drawn from the cylinder near the tip of the spark plug. A gasoline direct injection fuel injector operating in reverse flow was used as a high-speed sampling valve. Brake specific values reflect a combination of changes in dilution and, at different brake loads, changes in pumping work.

This paper develops fast reduced-order models for generic aircraft electromechanical actuators (EMA). The models derivation is described in detail. It is shown that constant power load representation has its own dynamics that depend both on the principal machine parameters and upon the pulse-width modulation algorithm used. The accuracy specification cannot be met unless these dynamics are considered. The mechanism to take these dynamics into account by reduced-order models is proposed. Simulation results demonstrate the accuracy within the specified frequency bandwidth and the significant improvement in the computational time. The reported models can be used in a wide range of aircraft power system simulations.

A modern aircraft wing contains many complex pipes and ducts which, amongst other functions, form the fuel management and bleed air systems. These parts are often fabricated from thin sheet material using a combination of forming and welding and the manufacturing process is predominantly manual requiring highly skilled labor. Since each wing may only contain one or two of each part type the product volumes are very low, typically a few hundred per year. This means that conventional mass production approaches used in, for example the automotive industry, are not economically viable and the parts are thus disproportionately expensive. The current fabrication process involves splitting the component into parts that can be press formed from sheet, laser trimmed and then manually welded together in a fixture. This process requires a perfect fit between the parts whose quality is reliant on the initial forming process.

Measurement assisted assembly is one of the key emerging technologies in airframe manufacture. The use of metrology to assist with the assembly process can significantly reduce the cost and complexity of the required fixtures as well as reducing manual labor input and assembly time. Most of the existing systems use a single metrology system but this paper describes the development and deployment of a network based system that allows the deployment of multiple metrology systems to support either a single task or multiple tasks simultaneously.

Kiva-3v Release 2 has been used to investigate combustion and emissions formation processes in a direct injection diesel engine with a high pressure common rail injection system. The influence of split main ratio and separation on NO and soot emissions have been of particular interest. Model validation has been based on comparisons with experimental data for heat release and engine-out emissions. Simulations have been carried out to explore the temporal development of combustion processes under typical part-load operating conditions. The results presented are for an engine speed and BMEP of 1600 rev/min and 6.76 bar, respectively.

Deposit control additives have been added to diesel fuel for over 30 years to prevent the build-up of deposits in the fuel injection system and thereby ensure optimum engine operation. As the complexity of modern diesel fuel injection systems has increased their tolerance to deposit formation has decreased and therefore there is now an even greater need for high quality deposit control additives. The predominant and most effective chemistry for diesel deposit control additives used over the past 30 years is polyisobutylene succinimides (PIBSI). The design and manufacture of these additives is critical to their performance in the field in terms of functioning to control deposits but also from a no-harm standpoint. Recent work has identified low molecular weight PIBSI as a cause of internal diesel injector deposits (IDID) associated with injector sticking.

Friction data have been acquired from motored engine tests on four designs of light duty automotive diesel engines with a swept capacity around two litres (1.8l-2.2l). The data cover temperatures at the start of motoring of -20°C and above, and motoring speeds from 200 rev/min to 1000 rev/min. Most tests were carried out using SAE 10W/30 oil. The breakdowns separated piston assembly, crankshaft assembly, valve train and auxiliary component contributions to friction mean effective pressure (fmep). The empirical coefficients and functions used in the engine friction model developed by Patton, Nitschke and Heywood (SAE 890836) have been modified to fit the low speed, low temperature test data without greatly affecting predictions for fully-warm conditions. The dependence of component contributions on oil viscosity during warm-up has been taken into account.

The paper reports the design of a model and HIL system produced to support the development and testing of Electronic Control Unit/Engine Management System (ECU/EMS) software for a V6 turbo-charged automotive diesel engine. The engine model, developed in Simulink, is compiled to execute on a dSpace platform and interacts with the ECU/EMS module in real time. The main features of the engine model are outlined. The configuration of the model and HIL components are described, and the performance of the system is illustrated and discussed. Practical decisions on the inclusion of real or virtual sensors and actuators, and other implementation issues, are explained. Recent and potential future applications of the system are described.

The paper outlines experimental investigations of fuel injection strategies which are possible using high pressure common rail fuel injection systems. Strategies using a split main with a pilot injection have been explored. The strategy variables were the ratio of the first to second part of the main, the separation between these and the timing of the start of main injection. Exhaust gas recirculation rate was a fourth variable. Pilot injection quantity and timing, and rail pressure were held constant. The influence on emissions and specific fuel consumption is described and the method of optimising settings is outlined. The manipulation of fuel injection settings to best meet optimisation targets for emissions and specific fuel consumption is described. The benefits compared to results for optimised single main injection are described, as are issues of strategy robustness.

There have been reports of internal injector deposits causing problems in diesel engines in the field from 2008. Such problems manifest themselves as rough idling, power loss, high emissions, high-pressure fuel pump wear, injector sticking, internal component corrosion and engine failure. These reports coincided with the use of common rail diesel injection systems and of ultra-low sulphur fuels introduced because of emission regulation demands. The injection systems have design features that are more conducive or susceptible to deposit formation such as severe high temperature and pressure operating conditions, the tolerances of critical parts, and lower force internal component actuation. The changes to fuels have also affected the fuels ability to solubilise these deposits. The deposits formed manifest themselves in complex form in the field, often being mixtures of inorganic and organic compounds.

Diesel fuel distilled from crude oil should contain no greater than trace amounts of sodium. However, fuel specifications do not include sodium; there is a limit of five parts per million for the amount of sodium plus potassium in fatty acid methyl esters (FAME) used as biodiesel. Sodium compounds are often used as the catalyst for the esterification process for producing FAME and sodium hydroxide is now commonly used in the refining process to produce ultra-low sulphur diesel (ULSD) fuel from crude oil. Good housekeeping should ensure that sodium is not present in the finished fuel. A finished fuel should not only be free of sodium but should also contain a diesel fuel additive package to ensures the fuel meets the quality standards introduced to provide reliable operation, along with the longevity of the fuel supply infrastructure and the diesel engines that ultimately burn this fuel.

The major drivers in the development of the latest generation of engines are environmental. For diesel engines, mitigating the effects of soot contamination remains a significant factor in meeting these challenges. There is general consensus of soot impacting oil performance. Considerable efforts have been made towards a greater understanding of soot-lubricant interaction and its effects on engine performance. However, with evolution of engine designs resulting in changes to soot composition/ properties, the mechanisms of soot-lubricant interaction in the internal combustion engine continue to evolve. A variety of mechanisms have been proposed to explain soot-induced wear in engine components. Furthermore, wear is not the only topic among researchers. Studies have shown that soot contributes to oil degradation by increasing its viscosity leading to pumpability and lubricant breakdown issues.

Global Navigation Satellite Systems (GNSS) can support the development of low-cost and high performance navigation and guidance architectures for Unmanned Aircraft Systems (UAS) and, in conjunction with suitable data link technologies, the provision of Automated Dependent Surveillance (ADS) functionalities for cooperative Sense-and-Avoid (SAA). In non-cooperative SAA, the adoption of GNSS can also provide the key positioning and, in some cases, attitude data (using multiple antennas) required for automated collision avoidance. A key limitation of GNSS for both cooperative (ADS) and non-cooperative applications is represented by the achievable levels of integrity. Therefore, an Avionics Based Integrity Augmentation (ABIA) solution is proposed to support the development of an Integrity-Augmented SAA (IAS) architecture suitable for both cooperative and non-cooperative scenarios.