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Hat-sections, single and double, made of steel are frequently encountered in automotive body structural components. These components play a significant role in terms of impact energy absorption during vehicle crashes thereby protecting occupants of vehicles from severe injury. However, with the need for higher fuel economy and for compliance to stringent emission norms, auto manufacturers are looking for means to continually reduce vehicle body weight either by employing lighter materials like aluminum and fiber-reinforced plastics, or by using higher strength steel with reduced gages, or by combinations of these approaches. Unlike steel hat-sections which have been extensively reported in published literature, the axial crushing behavior of hat-sections made of fiber-reinforced composites may not have been adequately probed.

An experimental fuel surrogate validation approach is proposed for a compression ignition application, and applied to validate a Jet-A POSF 4658 fuel surrogate. The approach examines the agreement of both physical and chemical properties of surrogate and target fuels during validation within a real compression-ignition engine environment during four sequential but distinct combustion phases. In-cylinder Mie Scattering measurements are applied to evaporating sprays to compare the behavior of the surrogate, its target fuel, and for reference, n-heptane. Early mixture formation and low temperature reaction behavior were investigated using 2-D broadband chemiluminescence imaging, while high temperature ignition and combustion chemistry were studied using OH chemiluminescence imaging. The optical measurements were combined with cylinder pressure-based combustion analysis, including ignition delay and premixed burn duration, to validate the global behavior of the surrogate.

The current extensive revisitation of the application of gasoline direct-injection to automotive, four-stroke, spark-ignition engines has been prompted by the availability of technological capabilities that did not exist in the late 1970s, and that can now be utilized in the engine development process. The availability of new engine hardware that permits an enhanced level of computer control and dynamic optimization has alleviated many of the system limitations that were encountered in the time period from 1976 to 1984, when the capabilities of direct-injection, stratified-charge, spark-ignition engines were thoroughly researched. This paper incorporates a critical review of the current worldwide research and development activities in the gasoline direct-injection field, and provides insight into new areas of technology that are being applied to the development of both production and prototype engines.

High-speed video of combustion processes and cylinder pressure traces were obtained from a single-cylinder optical-accessible engine with a production four-valve cylinder head to study the mixture formation and flame propagation characteristics at near-stoichiometric start condition. Laser-sheet Mie-scattering images were collected for liquid droplet distributions inside the cylinder to correlate the mixture formation process with the combustion results. A dual-stream (DS) injector and a quad-stream (QS) injector were used to study the spray dispersion effect on engine starting, under different injection timings, throttle valve positions, engine speeds, and intake temperatures. It was found that most of the fuel under open-valve injection (OVI) conditions entered the cylinder as droplet mist. A significant part of the fuel droplets hit the far end of the cylinder wall at the exhaust-valve side.

This paper investigates the use of an adaptive proportional-integral-derivative (APID) controller to reduce a combustion engine crankshaft speed pulsation. Both computer simulations and engine test rig experiments are used to validate the proposed control scheme. The starter/alternator (S/A) is used as the actuator for engine speed control. The S/A is an induction machine. It produces a supplemental torque source to cancel out the fast engine torque variation. This machine is placed on the engine crankshaft. The impact of the slowly varying changes in engine operating conditions is accounted for by adjusting the APID controller parameters on-line. The APID control scheme tunes the PID controller parameters by using the theory of adaptive interaction. The tuning algorithm determines a set of PID parameters by minimizing an error function. The error function is a weighted combination of the plant states and the required control effort.

The objective of this work is to develop a strategy to reduce the penalties in the diesel engine performance, fuel economy and HC and CO emissions, associated with the operation in the low temperature combustion regime. Experiments were conducted on a research high speed, single cylinder, 4-valve, small-bore direct injection diesel engine equipped with a common rail injection system under simulated turbocharged conditions, at IMEP = 3 bar and engine speed = 1500 rpm. EGR rates were varied over a wide range to cover engine operation from the conventional to the LTC regime, up to the misfiring point. The injection pressure was varied from 600 bar to 1200 bar. Injection timing was adjusted to cover three different LPPCs (Location of the Peak rate of heat release due to the Premixed Combustion fraction) at 10.5° aTDC, 5 aTDC and 2 aTDC. The swirl ratio was varied from 1.44 to 7.12. Four steps are taken to move from LTC to ALTC.

The objective of the research into modeling and simulation was to provide an improvement to the Wayne State EcoCAR 2 team’s math-based modeling and simulation tools for hybrid electric vehicle powertrain analysis, with a goal of improving the simulation results to be less than 10% error to experimental data. The team used the modeling and simulation tools for evaluating different outcomes based on hybrid powertrain architecture changes (hardware), and controls code development and testing (software). The first step was model validation to experimental data, as the plant models had not yet been validated. This paper includes the results of the team’s work in the U.S. Department of Energy’s EcoCAR 2 Advanced vehicle Technical Competition for university student teams to create and test a plug-in hybrid electric vehicle for reducing petroleum oil consumption, pollutant emissions, and Green House Gas (GHG) emissions.

Several mechanisms are discussed to understand the formation of both regulated and unregulated emissions in a high speed, direct injection, single cylinder diesel engine using low sulphur diesel fuel. Experiments were conducted over a wide range of injection pressures, EGR rates, injection timings and swirl ratios. The regulated emissions were measured by the standard emission equipment. Unregulated emissions such as aldehydes and ketones were measured by high pressure liquid chromatography and hydrocarbon speciation by gas chromatography. Particulate mass was measured with a Tapered Element Oscillating Microbalance (TEOM). Analysis was made of the sources of different emission species and their relationship with the combustion process under the different operating conditions. Special attention is given to the low temperature combustion (LTC) regime which is known to reduce both NOx and soot. However the HC, CO and unregulated emissions increased at a higher rate.

Simultaneous measurements of the radial and the tangential components of velocity are obtained in a high-speed, direct-injection diesel engine typical of automotive applications. Results are presented for engine operation with fuel injection, but without combustion, for three different swirl ratios and four injection pressures. With the mean and fluctuating velocities, the r-θ plane shear stress and the mean flow gradients are obtained. Longitudinal and transverse length scales are also estimated via Taylor's hypothesis. The flow is shown to be sufficiently homogeneous and stationary to obtain meaningful length scale estimates. Concurrently, the flow and injection processes are simulated with KIVA-3V employing a RNG k-ε turbulence model. The measured turbulent kinetic energy k, r-θ plane mean strain rates ( 〈Srθ〉, 〈Srr〉, and 〈Sθθ〉 ), deviatoric turbulent stresses , and the r-θ plane turbulence production terms are compared directly to the simulated results.

To address the need of increasing fuel economy requirements, automotive Original Equipment Manufacturers (OEMs) are increasing the number of turbocharged engines in their powertrain line-ups. The turbine-driven technology uses a forced induction device, which increases engine performance by increasing the density of the air charge being drawn into the cylinder. Denser air allows more fuel to be introduced into the combustion chamber, thus increasing engine performance. During the inlet air compression process, the air is heated to temperatures that can result in pre-ignition resulting and reduced engine functionality. The introduction of the charge air cooler (CAC) is therefore, necessary to extract heat created during the compression process. The present research describes the physics and develops the optimized simulation method that defines the process and gives insight into the development of CACs.

Cold starting problems of diesel engines are caused mainly by the failure of the auto-ignition process or the subsequent combustion of the rest of the charge. The problems include long cranking periods and combustion instability leading to an increase in fuel consumption in addition to the emission of undesirable unburned hydrocarbons which appear in the exhaust as white smoke. The major cause of these problems is the low temperature and pressure of the charge near the end of the compression stroke and/or the poor ignition quality of the fuel. This paper presents the results of an experimental investigation of cold starting of a high speed diesel engine with ULSD (Ultra Low Sulphur Diesel) and JP8 (Jet Propulsion) fuels at ambient temperature (25°C). A detailed analysis is made of the autoignition and combustion of the two fuels in the first few cycles in the cold start transient. In addition, a comparison is made between these processes for the two fuels during idle operation.

An automotive powertrain system consists of several interactive and linked nonlinear systems. This research focuses on the coordination of Gasoline Direct Injection (GDI) engine, transmission and emission aftertreatment systems. The goal is to design an optimal control strategy for driving performance, emissions (HC, CO, NOX), fuel economy and smoothness when switching engine mode and when shifting gears, under both discrete and continuous limitations. A multivariable control strategy is used to compromise among all powertrain subsystems to achieve optimal overall performance. A nonlinear discrete dynamic programming approach is proposed for hybrid system optimization. The complex multivariable automotive control problem is then simplified into an optimization problem. The feasibility of automotive hybrid control via the discrete dynamic programming approach is demonstrated by results from many numerical simulations under different operating conditions.

Vehicle weight-driven design comes amid rising higher fuel efficiency standards and must meet the criteria—pass proving ground (PG) test events that are equivalent to customer usage. Computer-aided engineering (CAE) fatigue analysis for PG is a successful push behind to digitally simulate vehicle durability performance with high fidelity. The need for vehicle weight reduction often arises in the vehicle development final phases when CAE methods, time, and tangible cost-effective opportunities are limited or nonexistent. In this research, a new CAE methodology is developed to identify opportunities for lightweight hole placement in the chassis structure and deliver a cost-effective lightweight solution with no additional impact on fatigue life. The successful application of this new methodology exhibits the effectiveness of the truck frame, which is the key chassis structure to support the body, suspension, and powertrain.

An experimental setup using rapid compression machine to provide excellent optical access to visualize simulated high-speed small-bore direct injection diesel engine combustion processes is described. Typical combustion visualization results of diesel spray combustion under different EGR, swirl, and injection pressure and nozzle conditions are presented. Different swirl intensities are achieved using an air nozzle with variable orientations and a check valve to connect the compression chamber and the combustion chamber. Different EGR ratios are achieved by pre-injection of diesel fuel prior to the main observation sequence. Clear visualization of the high-pressure fuel injection, ignition, combustion and spray/wall/swirl interactions is obtained. The injection system is a high-pressure common-rail system with either a VCO or a mini-sac nozzle. High-speed movies up to 35,000 frame-per-second are taken using a framing drum camera to record the combustion events.

"The Single Fuel Forward Policy" legislation enacted in the United States mandates that deployed U.S. military ground vehicles must be operable with aviation fuel (JP-8). This substitution of JP-8 for diesel raises concerns about the compatibility of this fuel with existing reciprocating piston engine systems. This study investigates the combustion, emissions, and performance characteristics of blends of JP-8 and Ultra Low Sulfur Diesel (ULSD) fuels with similar cetane numbers (CN), 48 (JP-8) and 47(ULSD), respectively, in a direct injection (DI) compression ignition engine over the load range of 3-8 bar imep at 1400 rpm. The results showed that JP-8 blends and ULSD had ignition delays ranging from approximately 1.0-1.4 ms and an average combustion duration time in the range of 47-65 CAD. Cylinder maximum heat flux values were found to be between 2.0 and 4.4 MW/m₂, with radiation flux increasing much faster than convection flux while increasing the imep.

A multiple-injection combustion strategy has been developed for heated gasoline direct injection compression ignition (HGCI). Gasoline was injected into a 0.4L single cylinder engine at a fuel pressure of 300bar. Fuel temperature was increased from 25degC to a temperature of 280degC by means of electric injector heater. This approach has the potential of improving fuel efficiency, reducing harmful CO and UHC as well as particulate emissions, and reducing pressure rise rates. Moreover, the approach has the potential of reducing fuel system cost compared to high pressure (>500bar) gasoline direct injection fuel systems available in the market for GDI SI engines that are used to reduce particulate matter. In this study, a multiple injection strategy was developed using electric heating of the fuel prior to direct fuel injection at engine speed of 1500rpm and load of 12.3bar IMEP.

SASOL IPK is a low cetane number synthetic fuel formed from coal by the Fischer-Tropsch process which can be used as an extender to JP8, currently used in military ground vehicles. This paper presents two surrogates developed considering the following criteria: (a) availability of kinetic combustion models for each component, (b) smallest number of components to reduce computation time and cost, (c) matching the following properties of target fuel DCN, distillation curve, density, LHV, MW and H/C ratio. The autoignition and combustion characteristics of the surrogates were validated in IQT according to ASTM D6890-10a. Surrogate formulation strategy involves an equation to calculate DCN of the surrogate mixture from the DCN of each component. The linear equation commonly used for such calculations was modified to include a multiplier, based on regression analysis, for each component to produces DCN values that agree well with the measured DCN in the IQT.

Combustion instability and white smoke emissions are serious problems during cold starting of diesel engines. In this investigation, a model has been applied to predict misfiring based on an analysis of the autoignition process. The effect of injection timing on combustion instability during the cold start transient, at different ambient temperatures is investigated, both theoretically and experimentally. Maps have been developed to show the zones where misfiring would occur. The experimental work was conducted on a direct injection heavy-duty diesel engine in a cold room. The room temperature covered a range from 21 ° C to -10 ° C. The cycle-by-cycle data analysis was made and results plotted on the developed maps. The experimental results correlated fairly well with the model prediction. Based on the analysis, a new strategy for cold starting can be developed to reduce combustion instability and white smoke emissions.

Combustion instability is investigated during the cold starting of a single cylinder, direct injection, 4-stroke-cycle, air-cooled diesel engine. The experiments covered fuels of different properties at different ambient air temperatures and injection timings. The analysis showed that the pattern of misfiring (skipping) is not random but repeatable. The engine may skip once (8-stroke-cycle operation) or twice (12-stroke-cycle operation) or more times. The engine may shift from one mode of operation to another and finally run steadily on the 4-stroke cycle. All the fuels tested produced this type of operation at different degrees. The reasons for the combustion instability were analyzed and found to be related to speed, residual gas temperature and composition, accumulated fuel and ambient air temperature.

The superior fuel economy of direct injection internal combustion engines (diesel and gasoline) is related to use of a high compression ratio to auto-ignite the fuel and the overall lean combustible mixture. Two of the major problems in diesel engine emissions are the NOx and soot emissions, which are caused by the heterogeneity of the charge and the properties of the diesel fuel. Conventional Direct Injection Spark Ignition Gasoline engines don't have these problems because of the fuel properties particularly its volatility. However, its efficiency and specific power output are limited by the knock, knock produced preignition and the sporadic preignition phenomenon. The Gasoline Direct Injection Compression Ignition (GDICI) engine combines the superior features of the two engines by increasing the compression ratio and use of gasoline as a fuel.