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A round-robin low cycle fatigue test program was conducted by the SAEFDE Committee using A356-T6 cast aluminum alloy. Three different microstructures representative of three solidification rates were sought, but only two significantly different secondary dendrite arm spacings, DAS, resulted. The smaller DAS had slightly greater monotonic yieid and ultimate strengths, greater permanent deformation at fracture and better low cycle fatigue resistance. Under strain-controlled axial low cycle fatigue conditions. A356-T6 was observed to cyclicaiiy strain harden and hysteresis loops were skewed toward the compressive stress from about 1 to 10 percent. Fatigue failures usually initiated at surface or near surface porosity. About 25 percent of the 173 test specimens that were considered valid failed between the strain gage knife edges and the specimen fillet radius.

Axial strain-controlled low cycle fatigue behavior was obtained from smooth specimens machined from spokes of A356-T6 cast aluminum alloy wheels. Two different foundries cast the wheels. Three wheels were used from one production run at one foundry and two wheels were used from two different production runs at the other foundry. Specimens from the three wheels of the same production run had essentially the same monotonic tensile properties and low cycle fatigue resistance. Specimens from the two wheels of the different production runs had different monotonic tensile properties and different low cycle fatigue resistance. All these A356-T6 wheel specimens cyclic strain harden with hysteresis loops typically offset to the compression side by five percent or less. The usual log-log linear model for low cycle fatigue adequately described the low cycle fatigue behavior.

The problem of cracks in cylinder heads due to low cycle fatigue (thermal fatigue) is well known for engines with high specific power output. However it is still difficult to predict the lifetime of a new cylinder head due to the number of influencing parameters and the complexity of material behavior. Better understanding of cylinder head fatigue can improve the development process of a new engine concerning CAE as well as mechanical testing efficiency. Therefore a CAE tool which can calculate strains and stresses as a function of time for a defined operating cycle of the engine was developed. In parallel a measuring technique was developed which allows to measure strains on the surface of the combustion chamber side of the cylinder head during fired engine operation. For different Aluminum-Silicon casting alloys the material behavior was described in the Finite Element Program ABAQUS by a nonlinear kinematic / isotropic hardening model.

Experience from several car projects shows that S-N curves for spot welds generated under load control in the high cycle fatigue regime might be very conservative when used in the low cycle fatigue regime. Therefore, force and displacement controlled low cycle fatigue tests were carried out on peel and shear loaded specimens. Both constant (CA) and variable amplitude (VA) load signals were used. Finally, a method for predicting fatigue life of spot welds with increased accuracy in the low cycle fatigue regime is proposed. The method is simple, fast and accurate and can be used together with linear finite element analysis (FEA) and existing fatigue packages.

Glass mat reinforced structural polyurethane foam or low density structural reaction injection molding (LD-SRIM) has found a niche in the manufacture of high quality, light weight, automotive, interior trim substrates. Current trends in the automotive industry indicate the need for cost reductions without sacrificing quality. A high productivity LD-SRIM system has been developed which meets this need. This cost reduction is achieved by the incorporation of an internal mold release agent and a 25 % decrease in demold time compared to current LD-SRIM technology. These technological advancements give the trim component manufacturer an increase in productivity by eliminating the time and labor required to apply external mold release and a shorter demold time. These advancements also provide for a significant reduction in the volatile organic compounds and cost associated with external mold release agents.

ICI Polyurethanes has developed a series of structural reaction injection molding resins for automotive interior trim applications. These new resin systems are CFC-free polyurethane foams specifically designed for glass mat reinforcement. These light weight composites can be described as low density structural RIM, LD-SRIM. LD-SRIM can offer a weight reduction of 50% over competitive materials with similar physical properties in applications such as door panels. A LD-SRIM composite with 20% glass reinforcement and a specific gravity of 0.55 g/cm3 has a flexural modulus of 2370 MPa. The LD-SRIM process has several benefits such as the consolidation of manufacturing steps achieved through molding in fasteners or decorative materials and the design flexibility inherent to liquid molding technology.

Aluminum alloys containing cerium have excellent castability and retain a substantial fraction of their room temperature strength at temperatures of 200°C and above. High temperature strength is maintained through a thermodynamically trapped, high surface energy intermetallic. Dynamic load partitioning between the aluminum and the intermetallic increases mechanical response. Complex castings have been produced in both permanent mold and sand castings. This versatile alloy system, using an abundant and inexpensive co-product of rare earth mining, is suitable for parts that need to maintain good properties when exposed to temperatures between 200 and 315°C.

Engine modelling aims at studying the combustion related phenomenon occurring in Internal Combustion (IC) engines. In this regard, a low dimensional mathematical model using first principles has been developed to study Spark Ignited (SI) engines. The resulting equations are Ordinary Differential Equations (ODE) (for volume, pressure, torque, speed and work done) and Partial Differential Equations (PDEs) for temperature and species conservation equations (fuel, CO, CO2, NO). This model utilizes simplified reaction kinetics for the oxidation of fuel in the combustion chamber. A two-step mechanism for the combustion of fuel and the classical Zeldovich Mechanism are used to predict the amount of NO formed during combustion. The model is solved in FORTRAN using LSODE subroutine (for stiff equations) with lumped parameters for thermal properties and diffusion, and invoking the ideal gas assumption.

1 This paper introduces and proves a novel automotive mirror base drag reduction method using passive jet flow control. The new concept is to open an inlet at the front part of the mirror, introduces the airflow via a converging duct, and ejects the jet surrounding the mirror surface at an angle toward the center of the mirror. The jet harnesses the energy from the free stream by jet mixing with the main flow via large coherent structures, entrains the main flow to energize the base flow, reduces the wake size and turbulence fluctuation, and ultimately significantly decreases the drag. Above phenomena are proved by wind tunnel testing with PIV and drag force measurement and CFD large eddy simulation (LES) calculation. Two jet mirrors with different inlet areas are studied. The jet mirror tunnel 1 has a smaller inlet area, and the jet mirror tunnel 2 has a 4.7 times larger inlet area. The wind tunnel testing is only done for the baseline and jet mirror tunnel 1.

In order to reduce particulate and NOx emission from the direct injection diesel engine, most researchers have been expecting the utilization of higher injection pressure and injection rate for improvement of diesel combustion. In the case of pump-line-nozzle system, the injection pipe line is very important with regard to the high injection pressure. Namely, the pipe line must be able to resist not only high pressure but also cavitation erosion. In this paper, the effect of high injection pressure, injection rate and sharp cutting at the end of fuel injection are discussed along with cavitation phenomena on the injection pipe line. And durability tests on the pipe line system under high injection pressure using a test rig are also described. Regarding durability tests, several measures have been taken for the injection pipe. As a result, the authors have found that the best solution for the injection pipe is a composite pipe made with SUS and steel.

The development of two low emission combustors for an automotive Rankine cycle engine is described. Emphasis has been placed on low emissions, fast response, compactness, and low parasitic power. Air atomization and rotary atomization of fuel have been incorporated, leading to two different combustor configurations. Emission characteristics of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) are described for both concepts. HC and CO emissions have been generally found to be well below 1976 federal standards for automotive emissions. Fine atomization of fuel and thorough air-fuel mixing have been found to be the keys to low NOx emissions. The use of exhaust gas recirculation reduced NOx emissions significantly. Effects of excess air and cooled primary zone are also shown.

Santa Barbara County is home to the largest offshore oil and gas production in California. The relative amount of NOx emissions from crew and supply boats servicing oil platforms compares to entire platform emissions. This, coupled with the need to reduce NOx in response to state and federal mandates, and the need for offshore operators to reduce offset liabilities, created the climate for joint effort with Detroit Diesel Corporation (DDC) to demonstrate the feasibility of on-road low emission engine technology on marine vessel engines. Two vessels were selected for a demonstration program. Specially developed DDC low emission engines were installed in a crew boat and a commercial tourist boat under this program. The program goals were to achieve a NOx emission level of 5 g/hp-hr on both the non-road 8-mode test cycle and under cruise operating conditions. In addition, a further goal was to achieve on-road emission levels for other pollutants.

A joint automotive and petroleum research program to develop prototype fuel and hardware requirements for low-emission vehicle systems is described. The relevance of the very stringent emission targets established by the Inter-Industry Emission Control (IIEC) program on the overall improvement in ambient air quality for the Los Angeles basin is illustrated. Three separate low-emission concept vehicle systems targeted to meet the very stringent emission targets of the IIEC program are described. Emission performance of these three systems on the recently published, more severe federal exhaust emission test procedures (July 15-November 10, 1970) are given. In addition, preliminary emission data are presented from a fourth low-emission concept vehicle system which combines the emission hardware features of the three earlier systems (thermal reactors with catalysts and an exhaust gas recirculation system).

Today, SULEV legislation represents the most stringent emission standard for vehicles with combustion engines, and it will be introduced starting by Model Year 2003. In order to meet such standards, even higher effort is required for the development of the exhaust gas emission concept of SI engines. Beyond a facelift of the combustion system, exhaust gas aftertreatment, and the engine management system, new approaches are striven for. The principle keys are well known: low HC feed gas, high thermal load for quick light-off, exhaust system with low heat capacity and highly effective exhaust gas aftertreatment.

We propose a new concept on simultaneous reduction of NO and soot emissions in Diesel engine exhaust by use of the diesel fuel oil (n-Tridecane) with liquefied CO2 dissolved. The CO2 dissolved component is expected to undergo flash boiling or gas separation when being injected into the combustion chamber, and improve spray atomization and mixing process both of which are primary factors to govern soot formation. Further, the internal EGR effect caused by CO2 component injected with the fuel is expected for NO formation. In order to assess this concept, spray dynamics measurement was conducted in the constant volume vessel with a variation of ambient pressure and temperature. Further, combustion experiments were carried out by using a rapid compression and expansion machine. Here, characteristics of the evaporative mixed fuel spray were examined by shadowgraph photography.

New environmental regulations require significant reduction of fuel consumption and engine emissions. This implies improvement of the internal combustion (I.C.) process, reduction of friction, development of complex after-treatment systems, and a reduction of oil consumption. New technical challenges are related to fuel dilution problems in diesel and super-ethanol engines; new wear problems are due to fuel dilution and soot loading in the lubricant; clogging and poisoning problems of after-treatment systems are related to oil consumption, etc. Therefore, researchers and engineers need appropriate tools to better understand and solve these new problems. The paper focuses on the combination of modern engine test beds equipped with innovative radionuclide techniques for real-time oil consumption, oil aeration, fuel dilution, and for on-line wear measurement.

As emission regulations for off-road engines become more and more stringent, alternative fuel off-road engines are being developed rapidly. This paper studies a closed-loop controlled LPG system, which was developed and tested on four lawn and garden engines. The four engines studied are Kohler 18hp, Kohler 13 hp, Briggs & Stratton 6 hp, and Briggs & Stratton 5hp engines, which power Toro walk-behind commercial lawn mowers, John Deere lawn tractors, John Deere walk-behind commercial lawn mowers, and Toro walk-behind commercial lawn mowers, respectively. All engines are four-stroke, spark-ignited and air-cooled. The fuel management system is an air valve based closed-loop controlled dedicated LPG system. The emissions and durability test results are presented. It was found that all engines operating on propane had significantly lower exhaust emissions than those of gasoline baselines.

This paper reviews the current and new engine technologies that are suitable to be implemented in light-weight outdoor power equipment that is mostly powered by two-stroke engines. It gives insight in the concerns associated with the improvement of known technologies and highlights trends for future engine developments. Among others, the paper covers ways for the conventional scavenging improvement, catalyst development, low pressure mixture injection, direct fuel injection, stratified scavenging and also four-stroke technology. These concepts are assessed with respect to performance, cost, size and weight. Special emphasis is laid on the research and development of a catalyst concept for high-performance two-strokes and direct fuel injection. The catalyst is one of the easiest and most effective ways for emission reduction. However, measures have to be found to overcome the severe thermal difficulties.

The development of efficient, durable three-way catalysts with OBD facilities needs cooperation between different areas related to engine, control and catalyst technologies. High-loading Pd and Pd-Rh precatalysts with λ sensors upstream and downstream were evaluated in FTP cycle to find out the appropriate driving conditions for OBD-II. Diagnostic values were calculated by the damping of λ responses caused by the aged precatalyst. The ratio of oxygen storage capacity (OSC) and precious metals were studied to improve the correlation between calculated diagnostic values and the catalyst efficiency. In fact, the correlation from diagnostic values was better to NOx than to THC efficiency by bag 1 and 2 emissions in FTP 75. The amplitude method with two λ sensors over warm converters is commonly used for OBD but hydrocarbon emissions are mainly formed during cold-start periods. Therefore the OBD calibration and catalyst optimal compositions have conflicting demands.

Today, natural gas engines for stationary and vehicular applications are not only faced with stringent emission legislation, but also with increasing requirements for power density and efficient fuel consumption. For vehicular use, downsizing is an advantageous approach to lowering on-road fuel consumption and making gas engines more competitive with their diesel counterparts. In SI-engines, the power density at a given compression ratio is limited by knocking, or NOx emissions. A decrease in compression ratio, lowering both NOx emissions and the risk of knocking combustion, increases fuel consumption. An increase in air-fuel-ratio, required to avoid knocking at higher thermal loading, increases boost pressure, HC and CO emissions, and mechanical loading and causes the danger of misfiring. As a result, the performance of the latest production gas engines for vehicles remains at a BMEP of 18…20 bar with a NOx emission level of 2…5 g/kWh.