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Technical Paper

Variation in Corrosion Resistance of Trivalent Chromate Coating Depending on Type of Zinc Plating Bath

Trivalent chromate coating is replacing the conventional hexavalent chromate coating applied on zinc plating. Zinc plating uses one of three types of plating baths (zincate, cyanide and chloride) according to the characteristics required of subject parts. It has been recognized that trivalent chromate coating provides different corrosion resistance depending on the type of zinc plating bath used. Zinc plating with chromate coating were analyzed to clarify the cause of the corrosion resistance variation with the type of zinc plating bath. It has been revealed that the chromate coating thickness and the condition of top SiO2 layer vary with the type of zinc plating bath, resulting in corrosion resistance variation.
Journal Article

Reaction Mechanism Analysis of Di-Air-Contributions of Hydrocarbons and Intermediates

The details of Di-Air, a new NOx reduction system using continuous short pulse injections of hydrocarbons (HC) in front of a NOx storage and reduction (NSR) catalyst, have already been reported. This paper describes further studies into the deNOx mechanism, mainly from the standpoint of the contribution of HC and intermediates. In the process of a preliminary survey regarding HC oxidation behavior at the moment of injection, it was found that HC have unique advantages as a reductant. The addition of HC lead to the reduction or metallization of platinum group metals (PGM) while keeping the overall gas atmosphere in a lean state due to adsorbed HC. This causes local O₂ inhibition and generates reductive intermediate species such as R-NCO. Therefore, the specific benefits of HC were analyzed from the viewpoints of 1) the impact on the PGM state, 2) the characterization of intermediate species, and 3) Di-Air performance compared to other reductants.
Technical Paper

Oxidation Stability of Diesel/Biodiesel Blends: Impact of Fuels Physical-Chemical Properties over Ageing During Storage and Accelerated Oxidation

Current and future engine technologies and fuels are mutually dependent. The increased use of alternative fuels has been linked to deterioration in performance of injectors, fuel filters and engines as a result of insoluble deposit formation. The present work aimed to study the impact of Diesel/biodiesel blends formulation (biodiesel feedstock and content) and temperature on the oxidation stability based on total acid number (TAN). The biofuels used in the fuel matrix were: rapeseed, soy and palm methyl esters (RME, SME and PME respectively). The Diesel/biodiesel blends were made with 0%v/v, 5%v/v, 10% v/v and 20%v/v of biodiesel blended with additive-free new Diesel. The oxidation stability of Diesel/biodiesel blends was to evaluate during 6 months fuels storage, under 20°C and 40°C, and fuels severe oxidation into a reactor vessel to better understand the parameters leading to fuel oxidation on-board.
Technical Paper

Oxidation Stability of Automatic Transmission Fluids -A Study by the International Lubricants Standardization and Approval Committee (ILSAC) ATF Subcommittee

The International Lubricant Standardization and Approval Committee (ILSAC) ATF subcommittee members have compared the two oxidation bench test methods, Aluminum Beaker Oxidation Test (ABOT) and Indiana Stirring Oxidation Stability Test (ISOT), using a number of factory-fill and service-fill ATFs obtained in Japan and in the US. In many cases, the ATFs were more severely oxidized after the ABOT procedure than after the same duration of the ISOT procedure. The relative severity of these two tests was influenced by the composition of the ATFs. The bench test oxidation data were compared with the transmission and the vehicle oxidation test data.
Technical Paper

New Conceptual Lead Free Overlays Consisted of Solid Lubricant for Internal Combustion Engine Bearings

Two types of new conceptual lead free overlays are developed for automotive internal combustion(IC) engine bearings. The overlays are consisted of molybdenum disulfide(MoS2) and polyamideimide(PAI) resin for binding. One of the overlays is suitable for diesel engines with higher unit load and the other overlay is suitable for gasoline engines with higher sliding velocity. Both overlays indicate good corrosion resistance and wear resistance comparing with conventional lead base overlay. Moreover, higher fatigue resistance is obtained in combination with high performance lead free bearing alloy. These new bearings have the potential to become alternative materials to conventional copper lead bearings with lead base overlay.
Technical Paper

Introduction of Durable Surface Conditioner Before E-Coat

Toyota Motor Corporation has been developing technologies for reductions on the environmental load. This paper reports the following as a part of technological development for the painting process. Prior to the application of the E-coat, vehicle bodies are pretreated with zinc phosphates. This is applied to ensure good adhesion and corrosion resistance of the E-coat film. To obtain an excellent pretreatment film, surface conditioning with titanium colloid is generally applied before pretreatment. Since colloid flocculation control was difficult in the case of a conventional titanium colloid-type surface conditioner, the surface conditioner had to be renewed at approximately two-month intervals. The liquid life, however, increased remarkably as a result of adopting fine zinc-type surface conditioners and adding an organic protective surface layer. The water supply/discharge amount was decreased significantly compared with previous amounts.
Journal Article

Influence of Bio Diesel Fuel on Engine Oil Performance

To evaluate the influence of FAME, which has poor oxidation stability, on engine oil performance, an engine test was conducted under large volumes of fuel dilution by post-injection. The test showed that detergent consumption and polymerization of FAME were accelerated in engine oil, causing a severe deterioration in piston cleanliness and sludge protection performance of engine oil.
Technical Paper

In Situ Observation of Catalysis Reactions Using Transmission Electron Microscope

Transmission electron microscope (TEM) is a powerful tool for studying catalyst materials at nano-size and/or atomic level. Conventional TEM usually needs to be observed at room temperature in high vacuum conditions. A gaseous atmosphere and high temperature condition may change the properties of catalyst materials. Recently we developed an in situ observation system in TEM for observing the oxidation and reduction under a gas atmosphere at high temperature. Using the new in situ observation system in TEM, the morphological changes of the nano particle and support were observed in the heated gaseous atmosphere at atomic level in real time.
Technical Paper

Effects of Bio-Fuels on Vehicle Performance: Degradation Mechanism Analysis of Bio-Fuels

In recent years, alternative sources of fuel are receiving a lot of attention in the automotive industry. Fuels derived from an agricultural feedstock are an attractive option. Bio-fuels based on vegetable oils offer the advantage being a sustainable, annually renewable source of automobile fuel. One of key issues in using vegetable oil based fuels is its oxidation stability. Since diesel fuels from fossil oil have good oxidation stability, automobile companies have not considered fuel degradation when developing diesel engines and vehicles as compared with gasoline engines. This paper presents the results of oxidation stability testing on bio-fuels. Oxidation stability was determined using three test methods, ASTM D525, EN14112 and ASTM D2274. The effects of storage condition, bio-fuel composition and antioxidants on the degradation of bio-fuels were all investigated. ASTM D525 is an effective test method to determine the effects of storage condition on bio-fuels stability.
Journal Article

Development of a Highly Anti-Corrosive Organic-Inorganic Hybrid Paint

A highly anti-corrosive organic-inorganic hybrid paint for automotive steel parts has been developed. The inorganic component included in the paint is silicon dioxide (SiO2), which has the capability to passivate zinc. By application of the paint on a trivalent chromatetreated zinc-plated steel sheet or a trivalent chromate-treated zinc-nickel-plated steel sheet, high anti-corrosion protection can be provided to steel materials. Particularly in the case of application over a zinc-nickel-plated steel sheet, 0 mm corrosion depth after a cyclic corrosion test (CCT) of 450 cycles was demonstrated.
Journal Article

Analysis of Influence of Snow Melting Agents and Soil Components on Corrosion of Decorative Chrome Plating

The dissolution and exfoliation of chromium plating specific to Russia was studied. Investigation and analysis of organic compounds in Russian soil revealed contents of highly concentrated fulvic acid. Additionally, it was found that fulvic acid, together with CaCl2 (a deicing agent), causes chromium plating corrosion. The fulvic acid generates a compound that prevents reformation of a passivation film and deteriorates the sacrificial corrosion effectiveness of nickel.
Technical Paper

Analysis for Relationship between Vehicle NOx Emission and Roadside NO2 Concentration

NO2 sources of roadside atmosphere at Matsubarabashi monitoring station in Tokyo were investigated analytically. The result showed that contribution of urban background is dominant from November to February and NO oxidation with O3 has large contribution from April to September. NO2 air quality standard will be achieved by reducing vehicle NOx emission to post-new long-term regulation level. The analytical method was verified by using our developed simulation system, which consists of micro traffic flow analyzer and CFD-based, unsteady-state diffusion with chemical reaction solver.