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Rapid Compression Machines (RCM) offer the ability to easily change the compression ratio and the pressure/mixture composition/temperature to gather ignition delay data at various engine relevant conditions. Therefore, RCMs with optical access to the combustion chamber can provide an effective way to analyze macroscopic spray characteristics needed to understand the spray injection process and for spray model development, validation and calibration at conditions that are suitable for engines. Fuel surrogates can help control fuel parameters, develop models for spray and combustion, and perform laser diagnostics with known fluorescence characteristics. This study quantifies and evaluates the macroscopic spray characteristics of multicomponent gasoline surrogates in comparison to their gasoline counterparts, under gasoline direct injection (GDI) engine conditions.

This paper presents results from experiments performed in an axisymmetric water analog model of a four-stroke IC engine using the optical velocimetry technique LIPA (Laser Induced Photochemical Anemometry). The investigation can be described as a fundamental scientific inquiry into the fluid dynamics encountered during engine operation, with the long term goal of increasing performance. An application of LIPA to a fluid dynamics problem delivers two-dimensional fields of velocity vectors which are projections of the full three-dimensional vectors in single measurement steps. From an evaluation of a velocity field vorticity information can be obtained readily. Velocity fields and vorticity distributions are, in this study, the basis for the evaluation of seven parametric quantities. Some of these may become tools that give engineers ‘rule of thumb’ indications of the mixing that is occurring.

Numerous studies have documented that lower extremity injury is second only to the head and face in automotive accidents. Such injuries are common because the lower extremity is typically the first point of contact between the occupant and the car interior. Of all lower extremity injuries, the knee is the most common site of trauma. This typically results from high speed contact with the instrument panel which can produce fracture and subfracture (contusions, lacerations, abrasions) level injuries. Current Federal safety guidelines use a bone fracture criterion which is based solely on a peak load. The criterion states that loads exceeding 10 kN will likely result in gross bone fracture. However, cadaver experiments have shown that increased contact area (via padding) over the knee can significantly increase the amount of load that can be tolerated before fracture or subfracture injury.

Camless Variable Valve Actuation (VVA) technologies have been known for improving fuel economy, reducing emissions, and enhancing engine performance. VVA can be divided into electro-magnetic, electro-hydraulic, and electro-pneumatic actuation. This paper presents an electro-hydraulic VVA design (called GD-VVA-2) that offers continuously variable timing and two discrete lifts (low lift S1 and high lift S2). The lift control is achieved through a lift control sleeve, which is hydraulically switched between two mechanically defined positions to provide accurate lifts. The low lift S1 has a wide design range, anywhere between zero and the high lift S2, i.e., 0 < S1 < S2. If S1 ≥ 0.5*S2, engine valves may operate at the low lift during most of a typical drive cycle. Operation at the low lift reduces energy consumption significantly. The GD-VVA-2 design offers compact package size and reasonable energy consumption.

Driver and passenger comfort, as related to automotive seats, is a growing issue in the automotive industry. As this trend continues, automotive seat designers and developers are generating a greater need for more anthropometrically accurate tools to aid them in their work. One tool being developed is the JOHN software program that utilizes three-dimensional solid objects to represent humans in seated postures. Contours have been developed to represent the outside skin surfaces of three different body types in a variety of postures in the sagittal plane. These body types include: the small female, the average male, and the large male.

Injuries to the lower extremities are common during car accidents because the lower extremity is typically the first point of contact between the occupant and the car interior. While injuries to the knee, ankle and hip are usually not life threatening, they can represent a large societal burden through treatment costs, lost work days and a reduced quality of life. The aim of the current study was to specifically study injuries associated with the knee and to propose a methodology which could be used to prevent future knee injuries. To understand the scope of this problem, a study was designed to identify injury trends in car crashes for the years 1979-1995. The NASS (National Accident Sampling System) showed that 10% of all injuries were to the knee, second only to head and neck injuries. Most knee injuries resulted from knee-to-instrument panel contact. Subfracture injuries were most common (contusions, abrasions, lacerations) followed by gross fracture injuries.

In an effort to create computer models to promote rapid, cost-effective prototyping while easing design changes, more information about how people interact with seats is needed. Predicting the occupant location, their geometry, and motion within a vehicle leads to a better determination of safety restraint location, controls reach, and visibility - factors that affect the overall operation of the vehicle. Based on the Michigan State University JOHN model, which provides a biomechanical simulation of the torso posture, experiments were conducted to examine the change of postures due to seat and interior package factors. The results can be incorporated into the posture prediction model of the RAMSIS program to give a more detailed prognosis of the spine curvature and refine the model-seat interactions. This paper will address findings of the experimental study with relation to model development.

Seat factors are characteristics of seats that influence people's postures. Seat factors such as lumbar prominence and seat pan stiffnesses were defined and measured for a variety of automotive seats. Seat factors such as these serve as a basis for evaluating and comparing seats. They were useful for selecting seats and designing experiments for human subject testing in the ASPECT program. Seat factors are also candidates for independent variables in statistical posture prediction models. The Seat factors described in this paper were measured with the current J826 manikin. They will be redefined for use with the new ASPECT manikin.

To assist automotive seat development and evaluation, a technique for predicting the posture of seated occupants has been developed. The method involved modeling the torso geometry and articulation of a mid-size male, based on information presented in SAE paper number 930110 [1]. This mid-size male model, known as 2-D JOHN, was developed in a commercial kinetic modeling software and used in a comparative seat evaluation study between a current production automotive seat and a prototype articulating seat. The 2-D JOHN model was supported a greater range of postures, defined as Total Lumbar Curvature (TLC) and Torso Recline Angle (TRA), in the prototype seat than the automotive seat.

Deformations of soft tissues and seat cushion foam are significant factors in determining the interface contours between the seat and the back of the thigh. This paper describes the measurement of forces, deformations, and contours of people's thighs and seat cushion materials. The goal of this work is to represent the human interactions with seats. A two-dimensional, plane strain finite element method was used to develop a contact model between the cross section of the human mid-thigh and flat surfaces, which can be a flat, rigid surface or a flat, foam cushion of various thicknesses and densities. Results of human and seat interactions for various subjects were measured, modeled, and compared. The present work showed a good agreement between experiments and models for various subjects and foam densities. The important results showed that the stiffness of the foam does not depend on the foam thickness.

As the variable nozzle turbine(VNT) becomes an important element in engine fuel economy and engine performance, improvement of turbine efficiency over wide operation range is the main focus of research efforts for both academia and industry in the past decades. It is well known that in a VNT, the nozzle endwall clearance has a big impact on the turbine efficiency, especially at small nozzle open positions. However, the clearance at hub and shroud wall sides may contribute differently to the turbine efficiency penalty. When the total height of nozzle clearance is fixed, varying distribution of nozzle endwall clearance at the hub and shroud sides may possibly generate different patterns of clearance leakage flow at nozzle exit that has different interaction with and impact on the main flow when it enters the inducer.

Three-dimensional transient simulations using KIVA-3V were conducted on a 4-stroke high-compression ratio, methanol-fueled, direct-injection (DI) engine. The engine had two intake ports that were designed to impart a swirling motion to the intake air. In some cases, the intake system was modified, by decreasing the ports diameter in order to increase the swirl ratio. To investigate the effect of adding shrouds to the intake valves on swirl, two sets of intake valves were considered; the first set consisted of conventional valves, and the second set of valves had back shrouds to restrict airflow from the backside of the valves. In addition, the effect of using one or two intake ports on swirl generation was determined by blocking one of the ports.

Piston temperature plays a major role in determining details of fuel spray vaporization, fuel film deposition and the resulting combustion in direct-injection engines. Due to different heat transfer properties that occur in optical and all-metal engines, it becomes an inevitable requirement to verify the piston temperatures in both engine configurations before carrying out optical engine studies. A novel Spot Infrared-based Temperature (SIR-T) technique was developed to measure the piston window temperature in an optical engine. Chromium spots of 200 nm thickness were vacuum-arc deposited at different locations on a sapphire window. An infrared (IR) camera was used to record the intensity of radiation emitted by the deposited spots. From a set of calibration experiments, a relation was established between the IR camera measurements of these spots and the surface temperature measured by a thermocouple.

The fluid motion inside the engine cylinder is transient, three-dimensional and highly turbulent. It is also well known that cycle-to-cycle flow variations have a considerable influence on cycle-to-cycle combustion variations. Laser-based diagnostic techniques, for example, particle image velocimetry (PIV) or molecular tagging velocimetry, can be used to measure two or three components of the velocity field simultaneously at multiple locations over a plane. The use of proper orthogonal decomposition (POD) allows quantification of cycle-to-cycle flow variations, as demonstrated using PIV data [1]. In the present work, POD is used to explore the cycle-to-cycle flow variations utilizing molecular tagging velocimetry data. The instantaneous velocity fields were obtained over a swirl measurement plane when engine was operated at 1500 rpm and 2500 rpm.

An auxiliary fueled prechamber ignition system can be used in an IC engine environment to provide lean limit extension with minimal cyclic variability and low emissions. Geometry and distribution of the prechamber orifices form an important criterion for performance of these systems since they are responsible for transferring and distributing the ignition energy into the main chamber charge. Combustion performance of nozzles with a single jet, dual diverging jets and dual converging jets for a methane fueled prechamber ignition system is evaluated and compared in a rapid compression machine (RCM). Upon entering the main chamber, the dual diverging jets penetrate the main chamber in opposite directions creating two jet tips, while the dual converging jets, after exiting the orifices, converge into a single location within the main chamber. Both these configurations minimize jet-wall impingement compared to the single jet.

Camless Variable Valve Actuation (VVA) technologies have been known for improving fuel economy, reducing emissions, and enhancing engine performance. VVA can be divided into electro-magnetic, electro-hydraulic, and electro-pneumatic actuation. A family of camless VVA designs (called LGD-VVA or Gongda-VVA) has been presented in an earlier SAE publication (SAE 2007-01-1295) that consists of a two-spring actuation, a bypass passage, and an electrohydraulic latch-release mechanism. The two-spring pendulum system is used to provide efficient conversion between the moving mass kinetic energy and the spring potential energy for reduced energy consumption and to be more robust to the operational temperature than the conventional electrohydraulic actuation; and the electrohydraulic mechanism is intended for latch-release function, energy compensation and seating velocity control.

Since the 1960's, automotive seats have been designed and evaluated with tools and procedures described in the SAE Recommended Practice J826. The SAE J826 design template and testing manikin each have a torso with a flat lower back shape and with a single joint at the H-point. The JOHN models provide a more anatomically detailed representation of human shape and movement. The articulations of the JOHN torso (pelvic, lumbar, and thoracic) segments are coupled so that their relative positions are determined by a single parameter related to spinal curvature. This paper describes the development and use of the JOHN biomechanical models for seating design.

Injury to the lower extremity during an automotive crash is a significant problem. While the introduction of safety features (i.e. seat belts, air bags) has significantly reduced fatalities, lower extremity injury now occurs more frequently, probably for a variety of reasons. Lower extremity trauma is currently based on a bone fracture criterion derived from human cadaver impact experiments. These impact experiments, conducted in the 1960's and 70's, typically used a rigid impact interface to deliver a blunt insult to the 90° flexed knee. The resulting criterion states that 10 kN is the maximum load allowed at the knee during an automotive crash when certifying new automobiles using anthropomorphic dummies. However, clinical studies suggest that subfracture loading can cause osteochondral microdamage which can progress to a chronic and debilitating joint disease.

Continuous efforts to improve thermal efficiency and reduce exhaust emissions of internal combustion engines have resulted in development of various solutions towards improved lean burn ignition systems in spark ignition engines. The Dual Mode, Turbulent Jet Ignition (DM-TJI) system is one of the leading technologies in that regard which offers higher thermal efficiency and reduced NOx emissions due to its ability to operate with very lean or highly dilute mixtures. Compared to other pre-chamber ignition technologies, the DM-TJI system has the distinct capability to work with a very high level of EGR dilution (up to ~40%). Thus, this system enables the use of a three-way catalyst (TWC). Auxiliary air supply for pre-chamber purge allows this system to work with such high EGR dilution rate. This work presents the results of experimental investigation carried out with a Dual Mode, Turbulent Jet Ignition (DM-TJI) optical engine equipped with a cooled EGR system.

This paper describes the design, implementation and testing of crankshaft-mounted pendulum absorbers used for reducing vibrations in a variable displacement engine. The engine can run in V8 and V4 modes, and without absorbers it experiences significant vibration levels, especially in V4 idle. The absorbers are tuned to address the dominant second order vibrations, and are slightly overtuned to account for nonlinear effects. The absorbers were designed to replace the large counterweights at the ends of the crankshaft, and thus serve for both balancing and vibration absorption. The engine was placed in a vehicle and tested for vibration levels at idle under various load conditions, and these results were compared with results obtained from a similar vehicle without absorbers. The tests demonstrate that these absorbers offer an effective means of vibration attenuation in variable displacement engines.