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Technical Paper

Future Automotive Technical Trends

1988-03-01
871155
This paper provides an overview of the automotive technology and its future trends mainly focussing on Japan. The future automotive technology will basically be on the projection of current technology, although it is expected more progress to be made in advanced and precision control systems. The application of electronics and development of new materials will play a very important role in this area.
Technical Paper

International Technical Transfer of Automobile Manufacturing

1989-11-01
891264
Automobile production technology has been transferred in the order of "automobile assembly technology", "automotive parts manufacturing technology" and "production preparation technology". Transfer of our "automobile assembly technology" has already been nearly 100% completed and, as the manufacture of local parts is promoted and our experiences to undergo model changes are widened, the transfer of "automotive parts manufacturing technology" and "production preparation technology" is making a steady progress. The most critical point that makes the technical transfer difficult is the small automobile markets in developing countries where it is impossible to acquire a sufficient production volume which permits satisfactorily low cost. Various measures to secure a sufficient production volume such as exports and complementation within regions have been taken so far, but any remarkable effect has not been achieved.
Technical Paper

Poisoning Deactivations of Automotive Catalysts by Lead and Phosphorus

1985-11-11
852219
The deactivation process of automotive catalysts by lead and phosphoruos were studied. The accelerated poisoning test were performed. The activity evaluation and characterisation of poisoned pellet oxidation catalysts showed the following origin of poisoning deactivations. Lead interacts with active materials and phosphorus covers over catalysts to reduce these catalytic performance. In the case of phosphorus and lead co-existence, the activity decreases rapidly because leadphosphate plugges pores of the support. In monolithic catalysts, highly axial distributions of poisons was obserbed. This characteristic distribution is advantageous for the durability of the catalyst.
Technical Paper

Carbon Dioxide Measuring Technology in Engine Combustion Chambers

2004-03-08
2004-01-1340
The authors have developed an instrument that measures the CO2 concentration in engine combustion chambers using the infrared absorption method. The characteristics of this technology are as follows: 1 Measuring can be carried out while the engine is running at 600r/min to more than 3000r/min, full load operation. (Applicable to all EGR conditions) 2 Quick response; 2ms 3 High linearity; ±1% Full Scale and under (FS: 10%) 4 No aggravation is caused to the intake/exhaust performance of engines This technology contributes to the improvement of the in-cylinder EGR system using, for instance, a variable valve-timing mechanism that is now expanding in number of applications, and also the conventional EGR system.
Technical Paper

Development of New Hybrid System for Compact Class Vehicles

2009-04-20
2009-01-1332
Toyota has been evolving a hybrid system since introducing the first mass-production hybrid vehicle in 1997 in response to the increasing automotive-related issues of CO2 emissions, energy security, and urban air pollution. This paper describes a newly developed hybrid system design and its performance. This system was developed with the main purpose to improve fuel consumption, especially for better real world fuel consumption; and to enhance its compatibility with multiple vehicle adoption by downsizing and reducing the weight of its components. At the same time, the hybrid system achieved improved power performance while satisfying stringent emission regulations in the world.
Technical Paper

Quantitative Analysis of the Relation between Flame Structure and Turbulence in HCCI Combustion by Two-Dimensional Temperature Measurement

2008-04-14
2008-01-0061
The structure of HCCI (homogeneous charge compression ignition) combustion flames was quantitatively analyzed by measuring the two-dimensional gas temperature distribution using phosphor thermometry. It was found from the relation between a turbulent Reynolds number and Karlovitz number that, when compared with the flame propagation in an S.I. engine, HCCI combustion has a wider flame structure with respect to the turbulence scale. As a result of our experimentation for the influence of low temperature reaction (LTR) using two types of fuel, it was also confirmed that different types of fuel produce different histories of flame kernel structure.
Technical Paper

A New Method to Analyze Fuel Behavior in a Spark Ignition Engine

1995-02-01
950044
In SI engines with port injection system, fuel behavior both in the intake port and in the cylinder has significant influence on the transient A/F characteristics and HC emissions [1]. Therefore, to improve the engine performance, it is very important to understand fuel behavior in the intake port and in the cylinder [2, 3]. This paper describes the following three unique methods to analyze fuel behavior in port injected SI engines and some test results. (1) Observation of fuel behavior in the intake port, using a transparent intake air tube and a strobe synchronized TV-photographic system. (2) Observation of fuel behavior in the cylinder, using a glass cylinder and fluorescent fuel. (3) Measurement of fuel wall wetting in the intake port and in the cylinder, using the engine with electronically controlled hydraulically driven in-take/exhaust valves.
Technical Paper

New Technology for Reducing the Power Consumption of Electrically Heated Catalysts

1994-03-01
940464
A new heating strategy for electrically heated catalysts has been developed which reduces power consumption while achieving the desired hydrocarbon conversion. The relationship between catalyst volume and power consumption is presented. Observations of catalytic reactions by a thermoviewer camera and mathematical simulations are used to optimize the heating pattern. Significant reductions in power consumption, while maintaining conversion efficiency, are reported by heating only the front face of the catalyst. However, prior to mass production additional work is required to improve durability, and reliability and to resolve manufacturing issues.
Technical Paper

Development of Three-Way Catalyst with Using Only Pd as Activator

1995-02-01
950257
The Pd only three-way catalyst with Rh as an activator completely removed has been developed. The catalyst has been improved with regards to its thermal stability and its NOx reduction capability in the fuel rich region. These two factors have been known as the weak points of Pd catalyst. The thermal stability of the Pd catalyst was improved by modifying the washcoat alumina to yield a higher thermal stability. On the other hand, the NOx reduction capability was controlled by adding a combination of La and Ba. The developed Pd only three-way catalyst demonstrated the equivalent performance to a current production Pt/Rh catalyst after engine dynamometer aging up to 800°C.
Technical Paper

Development of New Concept Three-Way Catalyst for Automotive Lean-Burn Engines

1995-02-01
950809
A new 3-way catalyst with NOx conversion performance for lean-burn engines has been developed. The catalyst oxidizes NOx and stores the resulting nitrate, which is then reduced by HC and CO during engine operation around the stoichiometric air/fuel ratio. Both the composition of the storage component and the particle sizes of the noble metal were optimized. In addition, a special air fuel mixture control has been developed to make the best of the NOx storage-reduction function. The present catalyst showed 90% conversion efficiency and improved fuel economy by 4% in the Japanese 10-15 mode test cycle. The efficiency remained at 60% or more after durability test.
Technical Paper

New Light Weight 3 Liter V6 Toyota Engine with High Output Torque, Good Fuel Economy and Low Exhaust Emission Levels

1995-02-01
950805
A new generation 3.0 liter V6 engine, the 1MZ-FE, has been developed. Through improvement of the basic technical characteristics of each individual component, the 1MZ-FE has achieved compactness, weight reduction and good fuel economy without adding systems or components. This new engine makes use of an aluminum cylinder block, and compared with the previous V6 engine, significant weight reduction of the crankshaft, connecting rods and pistons was achieved while still maintaining a high level of rigidity. To improve fuel economy, friction loss was reduced substantially by reducing the weight of moving parts and improving the surface roughness of sliding parts. The combustion was also improved through better fuel atomization by the air-assisted fuel injector and modification of the combustion chamber shape. Through these improvements the 1MZ-FE has achieved a weight reduction of approximately 20% and far greater vehicle fuel economy than before.
Journal Article

Development of Exhaust and Evaporative Emissions Systems for Toyota THS II Plug-in Hybrid Electric Vehicle

2010-04-12
2010-01-0831
Exhaust and evaporative emissions systems have been developed to match the characteristics and usage of the Toyota THS II plug-in hybrid electric vehicle (PHEV). Based on the commercially available Prius, the Toyota PHEV features an additional external charging function, which allows it to be driven as an electric vehicle (EV) in urban areas, and as an hybrid electric vehicle (HEV) in high-speed/high-load and long-distance driving situations. To reduce exhaust emissions, the conventional catalyst warm up control has been enhanced to achieve emissions performance that satisfies California's Super Ultra Low Emissions Vehicle (SULEV) standards in every state of battery charge. In addition, a heat insulating fuel vapor containment system (FVS) has been developed using a plastic fuel tank based on the assumption that such a system can reduce the diffusion of vapor inside the fuel tank and the release of fuel vapor in to the atmosphere to the maximum possible extent.
Journal Article

High Concentration Ethanol Effect on SI Engine Emission

2010-04-12
2010-01-1268
From the energy security and CO2 reduction point of view, much attention has been paid to the usage of bio-fuel. Recently, highly concentrated ethanol is used in some areas (“E85”; 85% ethanol and 15% gasoline in North America and Sweden, and “ethanol”; 93% ethanol and 7% water in Brazil). In these regions, Flexible Fuel Vehicles FFVs are being introduced that are capable of using fuels with a wide range of ethanol concentrations. Advantages of highly concentrated ethanol in internal combustion engine applications are higher thermal efficiency obtained due to higher octane number, and a reduction of nitrogen oxides due to lower combustion temperatures On the other hand, the latent heat of vaporization for ethanol is greater than gasoline, causing poor cold startability and high NMOG emissions. This paper examines the effect of highly concentrated ethanol on exhaust emissions at cold start in a SI- engine.
Technical Paper

Development of High-Strength Aluminum Piston Material

2010-04-12
2010-01-0220
Mass reduction of parts is growing in importance as a means for reducing CO2 emissions from vehicles.The aim of the present research was to contribute to further mass reduction of pistons by developing a new aluminum casting material with highest level of fatigue strength. This goal was achieved using a development concept of creating a homogeneous structure in which Ti was added to create a fine structure and appropriate quantities of Fe and Mn were added to form a compound that is stable at high temperatures. Stand-alone tests of prototype pistons fabricated using the developed material show that the material is 14% stronger than the conventional material, thereby enabling increases in power and mass reduction.
Technical Paper

Research on Improving Thermal Efficiency through Variable Super-High Expansion Ratio Cycle

2010-04-12
2010-01-0174
The compression ratio and expansion ratio are fundamental parameters that determine the thermal efficiency of an SI engine, and the potential of setting these ratios to arbitrary values was studied as a way of improving engine efficiency. First, the efficiency resulting from different compression and expansion ratios was calculated from a theoretical formula. As a result, it was verified that a 20% improvement in thermal efficiency could be expected by adopting a super-high expansion ratio of 20 or higher, which is an extremely large value for an SI engine, while keeping the compression ratio within a range that can ensure appropriate combustion. Subsequently, this research calculated the possibility of improving engine efficiency under a condition that constrains the swept volume to a constant value in consideration of practicability.
Journal Article

Development of Clean Diesel NOx After-treatment System with Sulfur Trap Catalyst

2010-04-12
2010-01-0303
Diesel engines with relatively good fuel economy are known as an effective means of reducing CO₂ emissions. It is expected that diesel engines will continue to expand as efforts to slow global warming are intensified. Diesel particulate and NOx reduction system (DPNR), which was first developed in 2003 for introduction in the Japanese and European markets, shows high purification performance which can meet more stringent regulations in the future. However, it is poisoned by sulfur components in exhaust gas derived from fuel and lubricant. We then developed the sulfur trap DPNR with a sulfur trap catalyst that traps sulfur components in the exhaust gas. High purification performance could be achieved with a small amount of platinum group metal (PGM) due to prevention of sulfur poisoning and thermal deterioration.
Journal Article

Simultaneous Reduction of NOx and PM in Diesel Exhaust Based on Electrochemical Reaction

2010-04-12
2010-01-0306
The emission regulations for diesel engines are continually becoming stricter to reduce pollution and conserve energy. To meet these increasingly stringent regulations, a new exhaust after-treatment device is needed. Recently, the authors proposed the simultaneous electrochemical reduction (ECR) system for diesel particulate matter (PM) and NOx. In this method, a gas-permeable electrochemical cell with a porous solid oxide electrolyte is used for PM filtering on the anode. Alkaline earth metal is coated on the cathode for NOx storage. Application of voltage to both electrodes enables the simultaneous reduction of PM and NOx by the forced flow of oxygen ions from the cathode to the anode (oxygen pumping). In this study, the basic characteristics of the ECR system were investigated, and a disk-shaped electrochemical cell was evaluated.
Technical Paper

Development of an Emergency Stop Assist System

2019-04-02
2019-01-1025
Social concern with traffic accidents caused by driver’s medical emergencies has been growing for the last several years. In Japan, the government issued technical guidelines in June 2016 to promote systems that deal with such accidents. Based on those guidelines, the Emergency Stop Assist system was manufactured in October 2017 to help reduce such accidents. This article first describes its purpose and core design, then presents an overview of the system, and finally discusses its effectiveness.
Technical Paper

Development of High Accuracy NOx Sensor

2019-04-02
2019-01-0749
This paper presents an improvement in the accuracy of NOx sensors at high NOx concentration regions by optimizing the manufacturing process, sensor electrode materials and structure, in order to suppress the deterioration mechanism of sensor electrodes. Though NOx sensors generally consist of Pt/Au alloy based oxygen pump electrodes and Pt/Rh alloy based sensor electrodes, detailed experimental analysis of aged NOx sensors showed changes in the surface composition and morphology of the sensor electrode. The surface of the sensor electrode was covered with Au, which is not originally contained in the electrode, resulting in a diminished active site for NOx detection on the sensor electrode and a decrease in sensor output. Theoretical analysis using CAE with molecular dynamics supported that Au tends to be concentrated on the surface of the sensor electrode.
Technical Paper

Application of Dynamic Mode Decomposition to Influence the Driving Stability of Road Vehicles

2019-04-02
2019-01-0653
The recent growth of available computational resources has enabled the automotive industry to utilize unsteady Computational Fluid Dynamics (CFD) for their product development on a regular basis. Over the past years, it has been confirmed that unsteady CFD can accurately simulate the transient flow field around complex geometries. Concerning the aerodynamic properties of road vehicles, the detailed analysis of the transient flow field can help to improve the driving stability. Until now, however, there haven’t been many investigations that successfully identified a specific transient phenomenon from a simulated flow field corresponding to driving stability. This is because the unsteady flow field around a vehicle consists of various time and length scales and is therefore too complex to be analyzed with the same strategies as for steady state results.
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