Search Results

The traction-drive integrated drive generator (T-IDG®) has been developed since 1999 to replace current hydrostatic transmission drive generators mounted on Japanese military aircraft. The T-IDG® consists of a generator and a half-toroidal traction-drive continuously variable transmission (CVT), which maintains a constant output speed of 24000 rpm, that is, a 400 Hz AC power supply. To cope with recent trends of more electric aircraft (MEA) and the need for weight reduction, a high-speed traction-drive CVT is advantageous over other transmissions. The torque on the half-toroidal variator is transmitted through multiple power rollers. The equal load sharing among power rollers is typically controlled by a mechanical hydraulic feedback system, whose stability is one of the main issues for the high-speed traction-drive CVT. Previous studies have shown that insufficient damping and stiffness of the mechanical hydraulic feedback system cause self-induced vibration.

A half-toroidal double-cavity CVT of 340 Nm transmission capacity was put into market in 1999. Following to this success, a challenge for transmitting higher torque by smaller size has been started. The design goal is set up to transmit 430Nm torque by using 6 power rollers instead of conventional 4 rollers. This CVT has new scientific and design issues on equal torque transmission among 6 power rollers and stability of speed ratio control mechanism. This paper describes the synchronizing mechanism of these 6 power rollers and the measurement of power-roller motion and efficiency.

We have reported the innovation of “An Intelligent Catalyst” which has the function for self-regeneration of Pd realized through the solid solution and segregation of Pd in a perovskite crystal [1, 2, 3, 4 and 5]. We have looked for a design configuration for LaFePdO3 perovskite in the washcoat by comparing single and double layer washcaots as well as different loading locations for precious metals in order to maximize the Intelligent Catalyst's function in the practical conditions. The catalysts were attached to an engine exhaust system and subjected to an accelerated aging. The bed temperature of the catalysts reached to 1050 °C. The performance of the catalysts was evaluated on the engine dynamometer. Catalytic activity and long durability were improved by development of the washcoat configuration. The optimum design of the washcoat was double-layer with a tri-metal (Pt, Rh and Pd) system. The perovskite was located in the lower layer.

The catalytic performance and On-Board Diagnostics (OBD) of the manifold catalyst having high Oxygen Storage Capacity (OSC) are described in this paper. First of all, we compared the performance of three-way catalysts containing Cerium - Zirconium - Yttrium oxide with Cerium - Zirconium oxide. Three-way catalysts dispersed Pt, Rh and Pd on Cerium - Zirconium - Yttrium oxide showed excellent catalytic performance especially at cold starting and at transient states, after high temperature aging at 1050°C. The performance of these catalysts was studied using the Driving Mode Simulation Dynamometer, which was developed in-house, and oxygen storage and release responses were compared in actual gas. Then we investigated the possibility of on-board diagnostics of catalyst deactivation with high OSC in manifold and close-coupled positions, a diagnostic which is usually assumed to be difficult to attain with present conventional technology.

Cerium oxide (CeO2) is known to have good oxygen storage capacity (OSC) and is used widely in three-way catalysts for automobiles, but it has a problem of inferior heat stability. In our previous work, cerium-zirconiumyttrium (Ce Zr-Y) oxide systems were investigated with the aim of improving the heat stability of CeO2-based oxide systems, and we found an optimum composition of Ce-Zr-Y oxide with platinum (Pt) showed good OSC even after high temperature aging. In this study OSC and thermal stability of Ce-Zr-Y oxide with varying the types of precious metals were investigated to evaluate the effect of precious metals. The results show that, Palladium (Pd) and Rhodium (Rh) are also available for Ce-Zr-Y oxide with precious metal system to improve OSC after thermal aging. In particular, Rh exhibited higher improvement than others at the composition of lower Ce content.

It is necessary to mount a three-way catalyst at a place near the engine such as a close coupled converter or manifold converter to decrease cold-start emission. Naturally, in that case the catalyst of course is used under considerable A/F fluctuations at higher temperatures. We have developed a catalyst with excellent durability under such severe conditions. Three types of catalysts, made with different loading locations of precious metals, were evaluated using model gases. Durability was found to strongly depend on the loading location, and thus it should be possible to design an optimal catalyst for close coupled and manifold converters.

Cerium oxide (Ceria) is known to have good oxygen storage capacity (OSC) and is used widely in three-way catalysts for automobiles, but it has a problem of heat stability since it is less stable than aluminium oxide (Alumina). In the present work, cerium-zirconiumyttrium (Ce-Zr-Y) oxide systems were investigated with the aim of improving the heat stability of CeO2-based oxide systems, which would result in great improvement in OSC. We found an optimum composition of Ce-Zr-Y oxide with platinum (Pt) dispersed in it at a quantity of 0.1 % in weight, which showed good OSC starting from 100°C upwards even after thermal aging at 1000°C for 2 hours under variable atmospheric conditions of rich-lean fluctuations.

Increasingly stringent emissions controls have led to a greater emphasis on strategies designed to minimize emission during cold start. One strategy employed is that of close-coupling the catalyst to the exhaust manifold of the engine in an effort to minimize catalyst light-off time. In this configuration, the catalyst must exhibit a high degree of thermal stability. Further, since the catalyst is situated nearer to the engine, it is more liable to sense cylinder-to-cylinder variations in exhaust gas composition and thus needs to possess a wider operating window than a catalyst positioned further underbody. We have previously reported that Perovskite-Pd catalysts exhibit excellent heat resistance and have three-way catalyst activity comparable with or superior to that of Pt-Rh/ Al2O3 catalysts and Pd/Al2O3 catalysts [1]*. Durability at high temperatures and oxygen storage capacity under large air/fuel (A/F) ratio fluctuation conditions have now been tested.

In spring 1987 Sumitomo Electric Ind. Ltd.(SEI) started production of an electronic antilock system for a Japanese car manufacturer. Features of this system are: 1. Extremely reliable due to - separate hydraulic control circuit. - dual electronic circuit. - self diagnostic function. 2. Improved pedal feel by using cut-off valves. 3. Easy addition of traction control system. This paper contains the basic concepts and details the components that make up the system.

This paper concerns mechanical fully automatic power transmissions for buses and trucks. Their design concept offers an additional two-pedal-controlled mechanism in conjunction with any conventional gearbox. The prototype consists of a five-speed gearbox and a single-plate clutch actuated by a transistorized electropneumatic control system. The electronic unit computes the shift points according to the accelerator pedal position, the vehicle speed and the selection of shift modulation, and controls the electric and pneumatic units for both clutch engagement and gear shift.