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Automobiles are a convenient and familiar means of transportation that are indispensable to various scenes in our daily lives, and their impact on the global environment is not small. Hitachi is now addressing measures to reduce the environmental burden caused by automobiles through the development of technologies for automotive products.
The reduction of CO2 emissions by automobiles poses an important issue for the prevention of global warming. Automobiles in Japan are said to emit as much as about 15% of the domestic total CO2 emissions. And recently, air pollution caused by such hazardous substances in the atmosphere as PM2.5 has become a social problem globally. Today, the environmental restrictions on automobiles raise a common issue for the entire world, and even developing countries are required to strengthen such restrictions to the level of advanced countries.
In line with those movements, such activities as the “improvement of engines” and “dissemination of electromotive vehicles (*1)” are now generally underway. Hitachi is addressing the development of technologies that support the progress being made in more efficient engines and electromotive vehicles, by taking the advantage of its ample experience, broad range of technological strengths, and rich expertise in total design and production.
Highly efficient engines are the key to reducing CO2 emissions by automobiles.
The engine is the so-called heart of any vehicle in terms of generating motive power. It generates an automobile' s motive power by taking in air and fuel and combusting the gaseous mixture. At that time, how efficiently the engine can convert the energy of combustion into kinetic energy without waste makes a big difference in fuel consumption, and becomes a key point for CO2 reduction.
In other words, CO2 emissions can be reduced by precisely controlling the air, fuel and ignition to achieve more ideal conditions for internal combustion, so as to achieve higher engine efficiency. For this purpose, a highly efficient engine management system that can coordinate the manufacturing technologies for those elements to produce an optimum effect is now being sought.
Hitachi offers a rich lineup of components that support a series of engine management system operations, and helps reduce CO2 emissions to an even greater extent by advancing the technologies for each of these components.
Because electromotive vehicles driven by electric motors are expected to significantly reduce CO2 emissions or maximize the recovery and recycling of energy, activities aiming to disseminate such vehicles are spreading worldwide. In recent years, electromotive vehicles have made remarkable progress, as evidenced by the production of such new vehicles as the plug-in hybrid electric vehicle (PHEV) that can be recharged using a domestic power source, the fuel cell electric vehicle (FCEV) that generates electric power through an oxygen-hydrogen chemical reaction, and other types.
An electromotive vehicle requires a “motor” (to convert electricity into motive power), a “battery” (to store electricity), and an “inverter” (to convert direct electric current from the battery into alternating current). Both motors and inverters have been downsized and made lighter for compact installation in the limited spaces of vehicles, are required to achieve higher efficiency, respectively.
At the same time, the energy-saving capability of electromotive vehicles (i.e. how efficiently they consume precious electric energy) is also a major issue.
In this context, a device that enables the recovery and recycling of energy is the “regenerative brake.” In fact, while the motor of an electromotive vehicle generates motive power, it also functions as a generator of electricity. When an electromotive vehicle slows down to stop, the motor converts the kinetic energy of wheels that continue spinning by inertia into electricity, which is stored in the battery.
Hitachi' s recently developed electrically-driven intelligent brake system can give the driver a natural sense of driving by controlling the balance of an engine' s friction brake and the motor' s regenerative brake at an optimum level, while deriving the maximum effect of regenerated energy. This technology leverages the reliable brake elements technology and motor control technology cultivated by Hitachi over many years, as well as its unique oil pressure generating mechanism.
Hitachi has also been endeavoring to develop a lithium-ion battery to be used primarily for electromotive vehicles, and has steadily accumulated its achievements, such as paving the way for mounting lithium-ion batteries in automobiles ahead of other companies.
In 2014, we developed a new lithium-ion battery that doubled (*2) the travel distance of electromotive vehicles as compared to that of previous ones.
Hitachi not only offers a lineup of the major components (motors, inverters and lithium-ion batteries), but also retains technologies for engines, brakes, control, etc., thereby contributing to the dissemination of electromotive vehicles.
The technology related to the environmental performance of conventional automobiles used to be optimized at the part and system levels, but along with the progress made in electromotive vehicles, optimization at the vehicle level (e.g. regenerative brake) has now become possible.
In the years to come, the computerization of automobiles is expected to further advance and collaboration between different automobiles or between automobiles and infrastructure will become possible, thereby resulting in progress toward optimization at the level of society. It can be assumed, for instance, that the alleviation of traffic congestion back to normalize flows of traffic is realized by providing traffic information to the vehicles being driven, or that electromotive vehicles play a role in the smart grid system that optimizes the power supply by utilizing IT, such as in the V2H (Vehicle to Home) system that links homes and automobiles by making it possible to use the power stored in a electromotive vehicle for household appliances.
By integrating the broad range of technologies that it retains with further advanced vehicles and infrastructure, Hitachi intends to help conserve the global environment in a manner that is more comfortable to people.