Toyota Technical Review

We publish "Toyota Technical Review (TTR)" with the aim of fostering partnerships through technology introductions to stakeholders and recording Toyota's technical assets. From 2023 (Vol.69), we changed the publication frequency from once a year to twice a year.

Contents

Special Feature: Multi-Pathway Approach toward Carbon Neutrality

• The Toyota Crown
  The spirit of innovation and challenge is at the heart of the DNA of the Crown, which was forged during Toyota's first independent development project shortly after the end of the Second World War by overcoming the difficulties involved in building a luxury vehicle. This DNA has since been inherited by every succeeding generation of the Crown. Developed to remain one step ahead of the times and deliver new value, the Crown is a cherished nameplate loved by many people. At the same time, the Crown has continued to change with the times to meet the constantly diversifying lifestyles and life stages of its customers. For the 16th generation, the development team carried out a thorough reexamination of what the Crown is about, resulting in a completely new lineup of models representing a Crown for a new era. This article outlines the details of the Crown and its technologies.
• The Evolution and Future Outlook of Automotive Power Semiconductors
  As part of its efforts to achieve carbon neutrality, Toyota offers a full lineup of electrified vehicles to its customers around the world, including battery electric (BEVs), hybrid electric (HEVs), plug-in hybrid electric (PHEVs), and fuel cell electric (FCEVs) vehicles. All these vehicles use power semiconductors to switch large currents on and off at high speeds. For this reason, power semiconductor performance has a major impact on vehicle power consumption efficiency, as well as the size and weight of powertrain components. Using the power control unit (PCU) as a reference case study, this article describes the historical evolution of power semiconductors, how power semiconductors have contributed to the advancement and greater practical application of electrified vehicles, and how power semiconductors have helped to popularize and increase the number of electrified vehicle options available to the customer.
• Powertrain Lubrication Technology Contributing to Electrification
  Toyota is working to develop a wide range of powertrains under a multi-pathway approach toward achieving carbon neutrality. Modifying and reducing the viscosity of lubricants are regarded as extremely effective measures for increasing the efficiency of these powertrain components. As an example of these measures, this article describes the development of a lubricant with dramatically reduced viscosity for use in transaxles, which is a common component used by all electrified vehicles. It also discusses the development status of a next-generation engine oil that is aiming to reduce viscosity based on a completely unconventional approach.
• Development of Low Conductivity Coolant for BEVs
  Toyota is aiming to help reduce CO2 emissions as part of measures to address global warming by preparing a wide range of product options in line with local conditions and customer needs around the world. Battery electric vehicles (BEVs) equipped with lithium-ion batteries have been attracting attention as one method to achieve this objective. However, coolant intrusion into these batteries can cause a short circuit, which may result in abnormal heat generation from the battery. Therefore, Toyota developed a low conductivity coolant specifically for BEVs to prevent abnormal heat generation in the battery due to short circuits caused by coolant intrusion. This coolant was adopted on the bZ4X, the first model in the bZ series, to reassure customers that BEVs can be driven safely and with peace of mind.
• Green Carbon, Blue Carbon
  As part of its efforts to achieve carbon neutrality by 2050, Toyota is engaged in a wide range of activities to reduce CO2 emissions while, at the same time, working to develop technologies capable of capturing and storing any CO2 that cannot be eliminated entirely. In addition to technologies that capture and store CO2 via artificial means, Toyota is also developing technologies to maximize the amount of carbon absorbed naturally by terrestrial or marine ecosystems, called green carbon and blue carbon, respectively. These development projects focused on the natural environment must also show careful consideration for the conservation of biodiversity. This article describes Toyota's activities related to green carbon, blue carbon, and biodiversity conservation in the context of real-world conditions and global trends.
• Saving the Japan of the Future! Planning and Development of the Mothership Aerial Platform Project
  Showing firm determination to help provide solutions for future social issues in Japan, Toyota has begun planning and development work on the Mothership project, which was named to reflect the idea of using a large wing-shaped high-performance kite as a high-altitude aerial platform. This article describes the vision and development strategy of this project. Inaugurated in 2018, the project started by carefully considering which main component technologies would be required, while designing and building small preliminary kites. Realized thanks to the passion and dedication of the development team, the kite systems and component technologies developed in this project have a wide range of potential applications in various industries. Toyota intends to continue development toward fulfilling the vision of the Mothership project with the aim of enhancing the performance of the kite to enable it to fly longer and higher, and to achieve its practical application.

Technical Papers/Technical Articles

• Development of Metallic Nanoparticles Contributing to Advancements in Mobility and the Adoption of the Internet of Things (IoT)
  Toyota is pursuing a number of mobility-based initiatives towards the realization of the Society 5.0 concept (also known as the "super smart society"), which has the potential to help resolve a wide range of social issues. One of the fundamental technologies with the potential to help achieve this goal is printed electronics, which involves the printing of nanoparticles on various substrates. Taking advantage of the assets nurtured through its long history of automotive materials development, Toyota has developed nanoparticles compatible with low-temperature sintering that can be used to realize printed electronics. This article describes an outline of this development. By popularizing this technology throughout society as well as for automotive applications, Toyota is aiming to help resolve social issues through the introduction of the systems envisioned by the Society 5.0 concept, encourage the growth of all types of related industries, and contribute to the realization of its mission to mass produce happiness.

Technical Award News

• Bipolar Type Nickel-Metal Hydride Battery
• Development of Automatic System for Vehicle Driveability Evaluations Using Machine Learning

List of Externally Published Papers

• List of Externally Published Papers for the first half of FY2023