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An experimental study was performed to develop a more fundamental understanding of the effects of secondary air injection (SAI) on exhaust gas emissions and catalyst light-off characteristics during cold start of a modern SI engine. The effects of engine operating parameters and various secondary air injection strategies such as spark retardation, fuel enrichment, secondary air injection location and air flow rate were investigated to understand the mixing, heat loss, and thermal and catalytic oxidation processes associated with SAI. Time-resolved HC, CO and CO₂ concentrations were tracked from the cylinder exit to the catalytic converter outlet and converted to time-resolved mass emissions by applying an instantaneous exhaust mass flow rate model. A phenomenological model of exhaust heat transfer combined with the gas composition analysis was also developed to define the thermal and chemical energy state of the exhaust gas with SAI.

One of the issues in stamping of advanced high strength steels (AHSS) is the stretch bending fracture on a sharp radius (commonly referred to as shear fracture). Shear fracture typically occurs at a strain level below the conventional forming limit curve (FLC). Therefore it is difficult to predict in computer simulations using the FLC as the failure criterion. A modified Mohr-Coulomb (M-C) fracture criterion has been developed to predict shear fracture. The model parameters for several AHSS have been calibrated using various tests including the butter-fly shaped shear test. In this paper, validation simulations are conducted using the modified (M-C) fracture criterion for a dual phase (DP) 780 steel to predict fracture in the stretch forming simulator (SFS) test and the bending under tension (BUT) test. Various deformation fracture modes are analyzed, and the range of usability of the criterion is identified.

Mechanisms of NH₃ generation using LNT-like catalysts have been studied in a bench reactor over a wide range of temperatures, flow rates, reformer catalyst types and synthetic exhaust-gas compositions. The experiments showed that the on board production of sufficient quantities of ammonia on board for SCR operation appeared feasible, and the results identified the range of conditions for the efficient generation of ammonia. In addition, the effects of reformer catalysts using the water-gas-shift reaction as an in-situ source of the required hydrogen for the reactions are also illustrated. Computations of the NH₃ and NOx kinetics have also been carried out and are presented. Design and impregnation of the SCR catalyst in proximity to the ammonia source is the next logical step. A heated synthetic-exhaust gas flow bench was used for the experiments under carefully controlled simulated exhaust compositions.

A new ring pack model has been developed based on the curved beam finite element method. This paper describes the first part of this model: simulating gas pressure in different regions above piston skirt and ring dynamic behavior of two compression rings and a twin-land oil control ring. The model allows separate grid divisions to resolve ring structure dynamics, local force/pressure generation, and gas pressure distribution. Doing so enables the model to capture both global and local processes at their proper length scales. The effects of bore distortion, piston secondary motion, and groove distortion are considered. Gas flows, gas pressure distribution in the ring pack, and ring structural dynamics are coupled with ring-groove and ring-liner interactions, and an implicit scheme is employed to ensure numerical stability. The model is applied to a passenger car engine to demonstrate its ability to predict global and local effects on ring dynamics and oil transport.

This study concerns a dissimilar materials joining technique for aluminum (Al) alloys and steel for the purpose of reducing the vehicle body weight. The tough oxide layer on the Al alloy surface and the ability to control the Fe-Al intermetallic compound (IMC) thickness are issues that have so far complicated the joining of Al alloys and steel. Removing the oxide layer has required a high heat input, resulting in the formation of a thick Fe-Al IMC layer at the joint interface, making it impossible to obtain satisfactory joint strength. To avoid that problem, we propose a unique joining concept that removes the oxide layer at low temperature by using the eutectic reaction between Al in the Al alloy and zinc (Zn) in the coating on galvanized steel (GI) and galvannealed steel (GA). This makes it possible to form a thin, uniform Fe-Al IMC layer at the joint interface. Welded joints of dissimilar materials require anticorrosion performance against electrochemical corrosion.

This article reports on the potential of negative valve overlap (NVO) for improving the net indicated thermal efficiency (η NIMEP) of gasoline engines during part load. Three fixed fuel flow rates, resulting in indicated mean effective pressures of up to 6 bar, were investigated. At low load, NVO significantly reduces the pumping loses during the gas exchange loop, achieving up to 7% improvement in indicated efficiency compared to the baseline. Similar efficiency improvements are achieved by positive valve overlap (PVO), with the disadvantage of worse combustion stability from a higher residual gas fraction (xr). As the load increases, achieving the wide-open throttle limit, the benefits of NVO for reducing the pumping losses diminish, while the blowdown losses from early exhaust valve opening (EVO) increase.

To improve the fuel economy via high EGR, combustion stability is enhanced through the addition of hydrogen, with its high flame-speed in air-fuel mixture. So, in order to realize on-board hydrogen production we developed a fuel reformer which produces hydrogen rich gas. One of the main issues of the reformer engine is the effects of reformate gas components on combustion performance. To clarify the effect of reformate gas contents on combustion stability, chemical kinetic simulations and single-cylinder engine test, in which hydrogen, CO, methane and simulated gas were added to intake air, were executed. And it is confirmed that hydrogen additive rate is dominant on high EGR combustion. The other issue to realize the fuel reformer was the catalyst deterioration. Catalyst reforming and exposure test were carried out to understand the influence of actual exhaust gas on the catalyst performance.

The windage tray effect on aeration in the engine sump was assessed by replacing much of the windage tray materials with wire meshes of various blockages. The mesh was to prevent direct impact of the oil drops spinning off the crank shaft onto the sump oil, and simultaneously, to provide sufficient drainage so that there was no significant build up of windage tray oil film that would interact with these droplets. Aeration at the oil pump inlet was measured by X-ray absorption in a production V-6 SI engine motoring at 2000 to 6000 rpm. Within experimental uncertainty, these windage tray changes had no effect on aeration. Thus activities in the sump such as the interaction of the oil drops spun from the crank shaft with the sump oil or with the windage tray, and the agitation of the sump oil by the crank case gas, were not major contributors to aeration at the pump inlet.

This paper reviews the relevant literature on the effects of sulfated ash, phosphorus, and sulfur on DPF, LNT, and SCR catalysts. Exhaust backpressure increase due to DPF ash accumulation, as well as the rate at which ash is consumed from the sump, were the most studied lubricant-derived DPF effects. Based on several studies, a doubling of backpressure can be estimated to occur within 270,000 to 490,000 km when using a 1.0% sulfated ash oil. Postmortem DPF analysis and exhaust gas measurements revealed that approximately 35% to 65% less ash was lost from the sump than was expected based on bulk oil consumption estimates. Despite significant effects from lubricant sulfur and phosphorus, loss of LNT NOX reduction efficiency is dominated by fuel sulfur effects. Phosphorus has been determined to have a mild poisoning effect on SCR catalysts. The extent of the effect that lubricant phosphorus and sulfur have on DOCs remains unclear, however, it appears to be minor.

The demands on valve seat insert materials, in terms of providing greater wear-resistance at higher temperatures, enhanced machinability and using non-environmentally hazardous materials at a reasonably low cost have intensified in recent years. Due therefore to these strong demands in the market, research was made into the possibility of producing a new valve seat insert material. As a result a high speed steel based new improved material was developed, which satisfies the necessary required demands and the evaluation trials, using actual gasoline engine endurance tests, were found to be very successful.

Application of microalloyed steel to automobile parts is becoming increasingly common in Japan. However, fatigue properties of actual automotive forged parts with slight notches on their surface have not been fully clarified. In this work, the fatigue properties of microalloyed steel were studied using test specimens and also actual automotive parts. The results indicated that microalloyed steel with an optimal microstructure showed higher notch fatigue resistance than quenched-tempered steel. The improvement of material technology and the application of microalloyed steel have not only served to bring product costs down, but have paved the way for part weight reductions. Lightweight connecting rods for the newly developed Nissan engines have been produced, contributing to improved engine performance.

Ceramic honeycombs have been used as automotive catalyst supports in US, Japan, Europe and other highly urbanized countries. Now, engine output is a great concern for automanufacturers, and reduction of the wall thickness of honeycomb substrates became indespensable for maintenance of gas flow restriction to a certain low level. To reduce wall thickness, material should be strong to maintain canning strength of substrates. Mechanical strength was improved with high density cordierite. However, isostatic strength of whole substrates was still insufficient with reduced thin walls for canning in spite of the material's high mecanical strength. Discussion is carried out on further possibility of improving canning performance of thin wall substrates as well as flow restriction, and warm up characteristics.

A new method for measuring unregulated substances in the exhaust gas is being investigated to clarify the influence of the vehicles' exhaust emissions into the environment. This paper explains our work on developing an analysis method for detecting and quantifying trace substances in the exhaust gas. A new analysis method was examined that uses thermal desorption to analyze trace amounts of polycyclic aromatic hydrocarbons (PAHs) in vehicle exhaust gas. This technique is faster than conventional methods and does not require any preconditioning of the samples before analysis. While lead and chloromethane were detected in the exhaust gas samples, it was made clear that these substances did not originate in the engine system. Accordingly, the results of this study indicate that careful attention must be paid to the test environment and the presence of measurement interfering substances in exhaust samples when measuring trace constituents in the exhaust gas from low-emission vehicles.

In Europe and the U.S., fracture split connecting rods are used in many types of current engines. This process can eliminate the machining of crankshaft end and eliminate the dowel pin for positioning. The most important key for fracture split connecting rods is a reduction in the plastic deformation during the fracture splitting process. For this reason, sinter-forged materials and pearlitic steels (C70S6) are used for fracture split connecting rods because of their low ductility. Such types of steel, however, are inferior to the hot forged microalloyed steels typically used as connecting rod material in Japan in terms of buckling strength and machinability although they are easier to fracture split. On the other hand, the conventional microalloyed steels used for connecting rods in Japan are not suitable for fracture splitting. The reason is that these steels have too much ductility and associated plastic deformation for fracture splitting.

To reduce quenching distortion, step gas quenching has been proposed in recent years, which refers to rapid gas cooling of steel from austenitizing temperature to a point above or below Ms temperature, where it is held for a specific period of time, followed by gas cooling. In this study, by using infrared thermography combined with conventional thermocouple, a new temperature monitoring and control system was developed to realize the step gas quenching process of a hypoid ring gear after low pressure carburizing. The test production results indicate that by using the new monitoring and control system, we can control the gas quenching process and the distortion of carburized gear treated by step gas quenching can be reduced significantly compared with standard gas quenching.

This paper explores the combined effects of boosting, intake air temperature, trapped residual gas fraction, and dilution on the Maximum Pressure Rise Rate (MPRR) in a boosted single cylinder gasoline HCCI engine with combustion controlled by negative valve overlap. Dilutions by both air and by cooled EGR were used. Because of the sensitivity of MPRR to boost, the MPRR constrained maximum load (as measured by the NIMEP) did not necessarily increase with boosting. At the same intake temperature and trapped residual gas fraction, dilution by recirculated burn gas was effective in reducing the MPRR, but dilution by air increased the value of MPRR. The dependence of MPRR on the operating condition was interpreted successfully by a simple thermodynamic analysis that related the MPRR value to the volumetric heat release rate.

Gas-pressurized space suits are highly resistive to astronaut movement, and this resistance has been previously explained by volume and/or structural effects. This study proposed that an additional effect, pressure effects due to compressing/expanding the internal gas during joint articulation, also inhibits mobility. EMU elbow torque components were quantified through hypobaric testing. Structural effects dominated at low joint angles, and volume effects were found to be the primary torque component at higher angles. Pressure effects were found to be significant only at high joint angles (increased flexion), contributing up to 8.8% of the total torque. These effects are predicted to increase for larger, multi-axis joints. An active regulator system was developed to mitigate pressure effects, and was found to be capable of mitigating repeated pressure spikes caused by volume changes.

Battery packs for Hybrids, Plug-in Hybrids, and Electric Vehicles are assembled from a system of modules (sheets) with a tight sheet metal casing around them. Each module consists of an array of individual cells which vary in the composition of electrodes and separator from one manufacturer to another. In this paper a general procedure is outlined on the development of a constitutive and computational model of a cylindrical cell. Particular emphasis is placed on correct prediction of initiation and propagation of a tearing fracture of the steel can. The computational model correctly predicts rupture of the steel can which could release aggressive chemicals, fumes, or spread the ignited fire to the neighboring cells. The initiation site of skin fracture depends on many factors such as the ductility of the casing material, constitutive behavior of the system of electrodes, and type of loading.

Simultaneous crank-angle-resolved measurements of gasoline vapor concentration, gas temperature, and liquid fuel droplet scattering were made with three-color infrared absorption in a direct-injection spark-ignition engine with premium gasoline. The infrared light was coupled into and out of the cylinder using fiber optics incorporated into a modified spark plug, allowing measurement at a location adjacent to the spark plug electrode. Two mid-infrared (mid-IR) laser wavelengths were simultaneously produced by difference-frequency-generation in periodically poled lithium niobate (PPLN) using one signal and two pump lasers operating in the near-infrared (near-IR). A portion of the near-IR signal laser residual provided a simultaneous third, non-resonant, wavelength for liquid droplet detection. This non-resonant signal was used to subtract the influence of droplet scattering from the resonant mid-IR signals to obtain vapor absorption signals in the presence of droplet extinction.

Thin sandwich sheets hold a promise for widespread use in automotive industry due to their good crash and formability properties. In this paper, thin stainless steel sandwich sheets with low-density core materials are investigated with regard to their performance in crashworthiness applications. The total thickness of the sandwich materials is about 1.2mm: 0.2mm thick facings and a 0.8mm thick sandwich core. Throughout the crushing of prismatic sandwich profiles, the sandwich facings are bent and stretched while the sandwich core is crushed under shear loading. Thus, a high shear crushing strength of the sandwich core material is beneficial for the overall energy absorption of the sandwich profile. It is shown theoretically that the weight specific shear crushing strength of hexagonal metallic honeycombs is higher than the one of fiber cores - irrespective of their relative density or microstructural geometry.