Search Results

An experimental study is performed to investigate the effects of charge motion control on in-cylinder fuel-air mixture preparation and combustion inside a direct-injection spark-ignition engine with optical access to the cylinder. High-pressure production injector is used with fuel pressures of 5 and 10 MPa. Three different geometries of charge motion control (CMC) device are considered; two are expected to enhance the swirl motion inside the engine cylinder whereas the third one is expected to enhance the tumble motion. Experiments are performed at 1500 rpm engine speed with the variation in fuel injection timing, fuel pressure and the number of injections. It is found that swirl-type CMC devices significantly enhance the fuel-air mixing inside the engine cylinder with slower spray tip penetration than that of the baseline case without CMC device. Combustion images show that the flame growth is faster with CMC device compared to the similar case without CMC device.

A separator is a membrane that prevents the physical contact between the positive and negative electrodes while enabling ionic transport. The integrity of the separator is vital to the performance and reliability of a battery. This paper presents finite element stress analysis for the separator in a lithium-ion battery using a macro-scale battery cell model. In this model, the porous electrodes were treated as homogenized media and represented with the effective properties estimated using the rule of mixtures. To compute the deformation due to lithium (Li) intercalation & deintercalation and temperature variation, the Li concentration distribution and temperature change due to electrochemical reactions must be known. These parameters were computed using a multi-physics model in COMSOL and mapped to the macro-scale model in ANSYS. Numerical simulations were conducted to identify the locations and magnitudes of the maximum strain and stress of the separator in the pouch cell.

In the design of small off-highway and utility engines for compliance with increasingly stringent emissions standards, one component which can potentially reduce engine exhaust-gas emissions without necessitating changes in other, more costly parts is the spark plug. From studies carried out in automobile engines, benefits have been reported when using different spark-plug electrode shapes or when aligning the plugs in the cylinder head in preferred directions. However, these benefits, observed in automotive overhead valve engines with well-mixed charges, have generally been modest? and spark plugs of conventional shape remain the most widely used today. In the case of off-highway and utility engines, which operate at substantially higher air-fuel ratios, often with poorly-mixed charges, the potential for improving performance by changing spark-plug shape has not been explored.

This paper discusses the feasibility and issues associated with integrating a consumer off-the shelf product into a vehicle. For this evaluation, we selected a handheld personal computer (HPC), cellular telephone and modem to integrate with the vehicle audio, climate and system controls. Connectivity between the HPC and the vehicle is established by the use of the standard infrared serial data link that comes with the HPC. Connectivity outside the vehicle uses a cellular telephone for voice and a cellular digital packet data (CDPD) modem for data. This system is built into the Dodge ESX-2 hybrid powered concept vehicle for demonstration.

The rapid growth of information technology has the potential to affect many of the reasons why people drive. The Internet is arguably the most significant recent milestone in the growth of information technology. This paper examines the ways Internet communication might affect the travel experience by a) eliminating traditional reasons for personal travel, b) providing new reasons, c) changing the balance between personal and freight travel, and d) changing trip length distribution. Changes of the types listed could affect the product demand "mix" for electric, hybrid-electric and fuel cell vehicles being developed.

Many engineering systems create unwanted noise that can be reduced by the careful application of engineering noise controls. When this noise travels down tubes and pipes, a tuned resonator can be used to muffle noise escaping from the tube. The classical examples are automobile exhaust and ventilation system noise. In these cases where a narrow frequency band of noise exists, a traditional engineering control consists of adding a tuned Helmholtz resonator to reduce unwanted tonal noise by reflecting it back to the source (Temkin, 1981). As long as the frequency of the unwanted noise falls within the tuned resonator frequency range, the device is effective. However, if the frequency of the unwanted sound changes to a frequency that does not match the tuned resonator frequency, the device is no longer effective. Conventional resonators have fixed tuning and cannot effectively muffle tonal noise with time-varying frequency.

The reliability of an electronic sensor in the automotive applications is assessed using data from Fleet Test and proving ground Vehicle Endurance test. These nonfailure data are multiply censored at different mileage. Reliability analysis of data with no failure is rarely discussed in most reliability literature. This paper applies the Weibull maximum likelihood analysis based on known values of the Weibull shape parameter to extract useful reliability information. The well-known Weibayes and Weibest methods are subsets of the discussed approach. The sensitivity of the change of reliability levels over a range of Weibull shape parameter values is also examined in our case. The Huang-Porter (1991) approach of obtaining a reliability lower bound regardless of the Weibull shape parameter values is also applied and its potential of practical application is discussed. Practical limitations of all methods are discussed.

Higher horsepower per liter engines have put more demand on the crankshaft, often requiring the use of forged steel. This paper examines cost reduction opportunities to offset the penalties associated with forged steel, with raw material and machinability being the primary factors evaluated. A cost model for crankshaft processing is utilized in this paper as a design tool to select the lowest cost material grade. This model is supported by fatigue and machinability data for various steel grades. Materials considered are medium carbon, low alloy, and microalloy steels; the effects of sulfur as a machining enhancer is also studied.

A running loss test procedure has been developed which integrates a point-source collection method to measure fuel evaporative running loss from vehicles during their operation on the chassis dynamometer. The point-source method is part of a complete running loss test procedure which employs the combination of site-specific collection devices on the vehicle, and a sampling pump with sampling lines. Fugitive fuel vapor is drawn into these collectors which have been matched to characteristics of the vehicle and the test cell. The composite vapor sample is routed to a collection bag through an adaptation of the ordinary constant volume dilution system typically used for vehicle exhaust gas sampling. Analysis of the contents of such bags provides an accurate measure of the mass and species of running loss collected during each of three LA-4* driving cycles. Other running loss sampling methods were considered by the Auto-Oil Air Quality Improvement Research Program (AQIRP or Program).

The purpose of this work was to develop a fiber optic imaging system for use in flow visualization studies at the Michigan State University Engine Research Laboratory. A flexible fiber optic image carrier was coupled with a high speed rotating prism camera to create a unique imaging system which can easily reach remote location test sites. The flow visualization study was conducted on a motored 3.5 L four-valve engine test rig. A 40 watt pulsed copper vapor laser was synchronized with the camera to produce motion picture film at 5000 frames per second (fps). The image carrier which is attached to the camera contained an 80 degree field of view (FOV) tip adapter for viewing the entire cross-sectional area of the cylinder. The area imaged was a radial plane located 3 cm from the intake valves. The engine rig was motored at 850 rpm with a flow rate of 18 kg/hr. Entrained microballoon seeding particles were filmed as they traveled through the cylinder.

An OEM Natural Gas Vehicle (NGV) has been developed to address recently enacted Clean-Fuel Vehicle legislation. The NGV incorporates advanced fuel storage and fuel metering technologies to produce very low emissions and to provide superior customer value compared to aftermarket conversion units.

The mechanical behavior of a commercially available single layer polypropylene (PP) separator was investigated using a dynamic mechanical analyzer (DMA). Samples were tested along the machine direction (MD) and transverse direction (TD). The tensile stress-strain, tensile creep and viscoelastic behaviors were studied. Experiments were performed in two conditions: (1) dry and (2) wet, i.e., samples submersed in dimethyl carbonate (DMC). The experimental results revealed that the mechanical properties of the separator were much lower while being submersed in DMC. This finding suggests that the mechanical properties measured at a dry condition may not be sufficient to represent the in-situ material behavior. Therefore, it is important to conduct material characterization in an environment close to the service condition.

This work presents a method for simultaneously capturing visible and infrared images along with pressure data in an optical Diesel engine based on the International 4.5L VT275 engine. This paper seeks to illustrate the merits of each imaging technique for visualizing both in-cylinder fuel spray and combustion. The engine was operated under a part load, high simulated exhaust gas recirculation operating condition. Experiments examining fuel spray were conducted in nitrogen. Overlays of simultaneously acquired infrared and visible images are presented to illustrate the differences in imaging between the two techniques. It is seen that the infrared images spatially describe the fuel spray, especially fuel vapors, and the fuel mixing process better than the high-speed visible images.

This study analyzes the vibration characteristics of the valve train of a 2.0L SOHC Chrysler Corp. Neon engine over a range of operating speeds to investigate and demonstrate the advantages and limitations of various dynamic measurements such as displacement, velocity, and acceleration in this application. The valve train was tested in a motoring fixture at speeds of 500 to 3500 camshaft rpm. The advantages of analyzing both time and frequency domain measurements are described. Both frequency and order analysis were done on the data. The theoretical order spectra of cam displacement and acceleration were computed and compared to the experimental data. Deconvolution was used to uncover characteristic frequencies of vibration in the system. The theoretical cam acceleration spectrum was deconvolved from measured acceleration spectra to reveal the frequency response function of the follower system.

A Methanol Concentration Smart Sensor has been developed to support the demand for alternately fueled vehicles operating on blends of methanol and gasoline in any mixture up to 85% methanol. The sensor measures concentration by exploiting the difference in dielectric properties between methanol and gasoline. The measurement is made based on the distributed capacitance of a coil of wire, contained in a reservoir through which the fuel passes. This signal, along with temperature compensation inputs, is then fed to an integral microprocessor, which provides a voltage output proportional to the methanol concentration of the fuel. The Powertrain Controller uses this information to modify injector pulse width and provide proper spark advance. This paper will explain the sensor's development methodology and function.

Typical sand-casting techniques have been shown to be inappropriate in pouring particulate reinforced aluminum metal matrix composite (Al-MMC) castings. New gating/risering configurations were necessary to produce castings of acceptable soundness. Several automotive components, including brake rotors, cylinder liners and camshaft thrust plates, were prepared using special techniques. Initial durability test results of several Al-MMC prototype components are presented.

In-cylinder flows in four-valve SI engines were examined by high frame rate flow visualization and two-component LDV measurement. It is believed that the tumble and swirl motion generated during intake breaks down into small-scale turbulence later in the cycle. The exact nature of this relationship is not well known. However, control of the turbulence offers control of the combustion process. To develop a better physical understanding of the in-cylinder flow, the effects of the cylinder head intake port configuration and the piston geometry were examined. For the present study, a 3.5L, four-valve engine was modified to be mounted on an AVL single cylinder research engine type 520. A quartz cylinder was fabricated for optical access to the in-cylinder flow. Piston rings were replaced by Rulon-LD rings. A Rulon-LD ring is advantageous for the optical access as it requires no lubrication.

Ring wear may not be a problem in most current automotive engines. However, a small alteration in the ring face geometry can significantly affect the hydrodynamic lubrication characteristics of the ring. This in turn can cause excessive frictional losses and blowby in an engine. As engines become more compact and highly loaded, ring wear is likely to be more severe than in current engines. In order to assess the effect of ring loading, a piston ring wear model has been developed through the use of ring dynamics analysis with the assumption of a linear relationship between ring wear and the friction work applied on the surface of the ring. This ring wear analysis clearly shows that the higher the engine speed, the lower the wear rates at the same power output. This finding is consistent with the limited experimental data available.

Chrysler Corporation has developed an 8.0-liter engine for light truck applications. Numerous features combine to produce the highest power and torque ratings of any gasoline-fueled light truck engine currently available while also providing commensurate durability. These features include: a deep-skirt ten-cylinder 90° “V” block, a Helmholtz resonator intake manifold that enhances both low and mid-range torque, light die cast all-aluminum pistons for low vibration, a unique firing order for smooth operation, a “Y” block configuration for strength and durability, a heavy duty truck-type thermostat to control warm up, and a direct ignition system.

This paper presents the development of a test procedure for evaluation of inadvertent deployment of air bags. The methodology and early development of the procedure is discussed along with additional criteria thought to be required for trucks and sport utility vehicles. Tests conducted address severe off-road use in relation to air bag sensing systems. Data is collected from accelerometers. After worst case test conditions are identified (examples include rough road, snow plowing and jerk towing events), the data is analyzed and comparisons for design decisions can be made.