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Homogeneous charge compression ignition (HCCI), combustion has the potential to be highly efficient and to produce low NOx, carbon dioxide and particulate matter emissions, but experiences problems with cold start, running at idle and producing high power density. A solution to these is to operate the engine in a ‘hybrid mode’, where the engine operates in spark ignition mode at cold start, idle and high loads and HCCI mode elsewhere during the drive cycle, demanding a seamless transition between the two modes of combustion through spark assisted controlled auto ignition. Moreover; HCCI requires considerable control to maintain consistent start of combustion and heat release rate, which has thus far limited HCCI's practical application. In order to provide a suitable control method, a feedback signal is required.

Usually, the simulation of a turbocharger included in a diesel engine model relies typically on the assumption of adiabaticity for the compressor. However experiments on a turbocharger test bench show that the heat transfers from the turbine to the compressor have a major influence on the compressor performances. So the manufacturers maps must be modified or used with a new method taking into account heat transfers. The methods proposed are a simple way to take into account heat transfers when the performance maps are used. They give results in relative good agreement with experimental measures in comparison to their easiness of use.

Experiments were performed on a single-cylinder heavy-duty Caterpillar SCOTE 3401E engine at high speed (1737 rev/min) and loads up to 60% of full load for fully Premixed Charge Compression Ignition (PCCI) combustion. The engine was equipped with a high pressure (150 MPa) Caterpillar 300B HEUI fuel injection system. The engine was run with EGR levels up to 75% and with equivalence ratios up to 0.95. These experiments resulted in compliance of NOx and PM emissions to 2010 emissions mandates levels up to the tested load. The set of experiments also demonstrated the importance of cylinder charge preparation by way of optimized start-of-combustion timing for sufficient in-cylinder mixing. It was found that increased EGR rates, even with the correspondingly increased equivalence ratios, increase mixing time and substantially decrease PM emissions.

Our previous work applied LIF measurements of in-cylinder fuel distribution to predict CO2, CO, and HC emissions from an HCCI engine under low-load stratified-charge conditions. The prediction method is based on the premise that local fuel-air packets at a given equivalence ratio (characterized using LIF imaging) burn as if in a homogeneous charge at the same equivalence ratio. Thus, emissions measured during homogeneous operation provide an emission-versus- equivalence-ratio look-up table for predicting stratified-charge emissions. The present paper extends the technique to predict engine-out NOX emissions. Because of operating-range limitations, NOX look-up data for homogeneous operation cannot adequately be determined by experiment. Instead, a CHEMKIN-based model provides this look-up table data instead.

An extensive experimental study is described whose main objective is to characterize the acoustic and flow dynamic response of turbocompressors to flow pulsation from a four cylinder high speed direct injection (HSDI) diesel engine. Four different turbochargers with centrifugal compressors of different size were considered, each one with a different turbine. Compressors were excited with pulsating flow in real engine conditions. Wave decomposition was used to obtain incident and reflected pressure perturbations upstream and downstream of the turbochargers, which allowed determining the zones of the compressor charts where they are more permeable to pressure oscillations, and to study the correlation of these magnitudes with turbocharger operating conditions.

A new family of high specific power 4-stroke outboard engines was developed. This new family of inline, supercharged and charge air cooled engines was targeted to deliver best in class torque curve for superior boat performance. Program performance targets were met by developing an outboard specific supercharger and charge air cooler, high efficiency gas exchange system, and optimized combustion process while maintaining durability targets.

The automotive industry continues to look for opportunities to reduce weight and cost while simultaneously increasing performance and durability. Since the introduction of aluminum cylinder blocks and heads, very few “innovations” have been made in powertrain design and materials. Cast crankshafts have the potential to produce significant weight savings (3-18 kg) with little or no cost penalty. With the advent of new, high strength, cast ductile iron materials, such as MADI™ (machinable austempered ductile iron), which has the highly desirable combination of good strength, good toughness, good machinability and low cost, lightweight crankshafts are posed to become a high volume production reality. An extreme demonstration of a lightweight crankshaft is the current use of a cast MADI crankshaft in the 1100 HP Darrell Cox sub-compact drag race car.

A detailed study, by finite element method (FEM), was conducted on an automotive engine exhaust valve subject to various loads (i.e. spring load, combustion pressure load, temperature profile and valve impact closing velocity). The 3D nonlinear (contact element and temperature-dependent) thermal-mechanical model was constructed and implicit time integration method was employed in transient dynamics under impact velocity. The predicted temperatures and maximum valve stress under impact velocity via FEM were compared with the measured test data, which were in good agreement. In addition, this study finds that the energy transfer during valve closing in normal engine operation is mainly conservative, and a linear relation exists between valve closing velocity and maximum stem stress, that was also confirmed by both test data and analytical expression presented using elastic wave and vibration theory.

Commonly, a significant event is detected when a normally stable engine parameter (ex. sensor voltage, sensor current, air flow, pedal position, fuel level, tire pressure, engine acceleration, etc.) transiently exceeds a calibrated detection threshold. Many implementations of detection thresholds rely on multi-input lookup tables or functions and are complex and difficult to calibrate. An approach is presented to minimize threshold calibration effort and complexity, while improving detection performance, by dynamically computing thresholds on-line based on current real-time data. Determining engine synchronization without a camshaft position sensor is presented as an illustrative application.

In the feedforward part of SI engine Air/Fuel control system, the in-cylinder mass air flow rate has to be accurately estimated in order to determine the fuel amount to be injected. Generally, this evaluation is performed either with a dedicated sensor (MAF sensor) or with an indirect evaluation based on the speed-density method. In this paper we propose a soft computing mass air flow estimator for a single-cylinder gasoline engine which is able to estimate, by using the combustion pressure signal, the incoming mass air flow both in steady states and in transient conditions.

This is a fundamental analysis of an extended stroke, SI engine accomplished by comparing its performance to a typical engine with exactly the same piston data. The stroke extensions include the intake and power strokes, with longer crankshaft durations of 202 degrees, and the compression and exhaust strokes, with shorter crankshaft durations of 158 degrees. The primary focus of the analysis is to determine the impact on performance attributed solely to the mechanical differences of the two engines. This was accomplished by using an Air Standard Otto Cycle analysis which neutralized potential differences in combustion effects. The secondary focus is a qualitative discussion on potential improvements in combustion efficiency.

In the context of modern engine control, one important variable is the individual Air Fuel Ratio (AFR) which is a good representation of the produced torque. It results from various inputs such as injected quantities, boost pressure, and the exhaust gas recirculation (EGR) rate. Further, for forthcoming HCCI engines and regeneration filters (Particulate filters, DeNOx), even slight AFR unbalance between the cylinders can have dramatic consequences and induce important noise, possible stall and higher emissions. Classically, in Spark Ignition engine, overall AFR is directly controlled with the injection system. In this approach, all cylinders share the same closed-loop input signal based on the single λ-sensor (normalized Fuel-Air Ratio measurement, it can be rewritten with AFR as they have the same injection set-point.

The use of natural fibers for polymer composite materials has increased tremendously in the last few years. This type of reinforcements offers many advantages such as low density, low cost, high specific strength and low environmental impacts. The performance of the natural fiber composites are affected by the fiber loading, the individual mechanical properties of each component (fiber and matrix), and the fiber and matrix adhesion. Concerning the interfacial interaction, natural fibers present a major drawback because of poor compatibility of fibers with most hydrophobic thermoplastic and thermoset matrix. Hemp fiber/acrylic composites were manufactured with sheet molding technique recently. Although mechanical tests give promising results, they exhibit low tensile strength resulting from a poor fiber/matrix adhesion. The moisture resistance property of the sheet molded composites also needs further improvement.

Solenoid actuated Injection valves are typically driven open loop by a pre-determined voltage or current profile. There is unit-to-unit variation of the valve electromagnetic/mechanical parameters as well as electrical supply transients, flow force transients and operating conditions while the drive voltage or current profile is fixed. Hence, by definition open loop drive is sub optimal. Extensive on engine calibration is necessary to correlate the movement of the armature to the current profile in the solenoid. Valve closure (the point at which the valve hits the stop corresponding to max armature stroke) is typically detected based on detecting an inflection point in the current profile. This method of closure detection is not reliable and is fundamentally flawed because the current profiles of valves can exhibit several other inflexion points due to bouncing (several closure events), non-linearity in valve inductance, back electromotive force (BEMF) characteristics, noise etc.

Natural fiber reinforced polymer composites are beginning to find their way into the commercial automotive market. But, inadequate adhesion between hydrophilic natural fibers and hydrophobic matrix materials affects the performance of the resulting composites. In this study the effect of an environmental friendly fungal treatment on the adhesion characteristics of natural fibers is investigated. Firstly, changes in acid-base characteristics of the modified hemp fibers were studied using Inverse Gas Chromatography (IGC). Afterwards, composites were prepared using Resin Transfer Molding (RTM) process and the effect of modification on performance and durability of the composites was investigated.

New and exciting possibilities in vehicle control are revealed by the consideration of topography, for example through the combination of GPS and three dimensional road maps. How information about future road slopes can be utilized in a heavy truck is explored. The aim is set at reducing the fuel consumption over a route without increasing the total travel time. A model predictive control (MPC) scheme is used to control the longitudinal behavior of the vehicle, which entails determining accelerator and brake levels and also which gear to engage. The optimization is accomplished through discrete dynamic programming. A cost function that weighs fuel use, negative deviations from the reference velocity, velocity changes, gear shifts and brake use is used to define the optimization criterion. Computer simulations back and forth on 127 km of a typical highway route in Sweden, show that the fuel consumption in a heavy truck can be reduced with 2.5% with a negligible change in travel time.

In the DOE-Delphi Composite Chassis Cross-Member program, 3TEX 3Weave™ (3D woven fiberglass mat)/vinyl-ester (Dion 9800™) composites have been investigated as a candidate material. One of the most important mechanical properties for qualifying these composites for such applications is the mechanical fatigue longevity. In this work, a predictive math-based technology has been developed as a virtual engineering tool for the design of 3TEX 3Weave™/vinyl-ester composite parts by using a state-of-the-art simulator, GENOA™ (Generalized Optimization and Analysis) PFA (Progressive Failure Analysis), developed jointly by Alpha Star Corp and NASA. This math-based GENOA™ methodology effectively tracks the details of damage initiation, growth, and subsequent propagation to fracture, for composite structures subjected to cyclic fatigue, thereby predicting the fatigue life.

The paper describes a first-of-its-kind attempt of authors to develop an intake manifold - combined with - rocker cover (IMCRC) in sheet molding compound (SMC) for 3 L and 4 L direct injection diesel engines with power ratings 75 kW and 92 kW respectively. The objective was to reduce overall engine weight, noise and cost. The intake manifold is designed to withstand absolute boost pressures of more than 2 bar, temperature in the range of 160 °C. and capable of carrying load of directly attached components such as an air intake pipe. It is worth to note that the designed SMC component always remains in the vicinity of the exhaust manifold by virtue of base engine layout constraint. The development if successful can expand the horizon of SMC in diesel engine application.

Use of natural fiber and / or hybrid thermoplastic composites in the automotive industry can provide the advantages of weight reduction, cost reduction and recyclability, in addition to eco-efficiency and renewability compared to synthetic conventional materials. Besides the mechanical performance of the composites, thermal properties, durability, and recyclability of the natural fiber or hybrid composites are also to be investigated to demonstrate their potential candidacy as structural members in automotive applications. The main objective of this research work was to evaluate thermal properties, creep properties, and recyclability of the natural fiber and natural fiber hybrid composites in comparison with 30-40wt% long glass fiber filled thermoplastic composites. Composites were prepared by melt blending the thermoplastic, fiber and compatibilizer followed by granulation and injection molding of the compound into test specimens.

Recently, to enhance passenger comfort, air suspension systems with rubber tube have been replacing conventional coiled spring type suspension in automobile suspension systems. In this study, the optimum design of rubber and cord materials in rubber tube, aimed at improving the performance of the air suspension system, has been studied. To determine the optimum design, the study altered the fillers and antioxidants in CR (chloroprene rubber) compounds with good ozone-resistance properties, and changed the angles and thickness of the nylon cord. The study produced rubber tubes using cord-reinforced rubber composite materials, then analyzed and measured the resultant physical properties, microstructure, and dimensions. It also evaluated the load capacity, static and dynamic spring characteristics, outer diameter changes, and pressure changes in the loading, and determined the burst pressure of air suspension.