DENSO Develops New Hybrid Vehicle Components

New components installed on Lexus GS450h

TOKYO, April 3 -- DENSO Corporation has developed three components for hybrid vehicles that are smaller, lighter, and deliver better performance: a DC-DC converter, a battery-monitoring unit, and a system main relay.

The Lexus GS450h, with these components installed, was launched in Japan in March. The components will be introduced worldwide on the Lexus GS450h, with the vehicle's launch in the United States in April and in Europe in May.

DC-DC Converter

The DC-DC converter converts the high voltage (288 volts) supplied by the main battery to a lower voltage to charge a 12-volt auxiliary battery and supply electric power to various accessories such as headlamps, wipers and the horn.

For its new DC-DC converter, DENSO developed a unique power conversion circuit that reduces energy loss by half compared to a conventional DC-DC converter, decreasing the amount of heat generated during power conversion, and improving fuel consumption. This enables the DC-DC converter to be cooled by air instead of the conventional method of cooling by water, allowing more flexibility in installation location.

Battery-monitoring Unit

The battery-monitoring unit monitors the voltage, current and temperature of the high-voltage battery.

Conventional battery-monitoring units place only low voltage elements on both sides of the circuit board. DENSO's new battery-monitoring unit places not only low voltage elements but also high voltage elements on both sides of the circuit board. This, along with reducing the number of elements, enables the new battery-monitoring unit to be approximately 65 percent smaller and approximately 50 percent lighter than conventional products.

System Main Relay

The system main relay connects and disconnects electric currents between the high-voltage battery and high-voltage system by controlling the contact of movable and fixed parts. It also shuts off the high electrical voltage in a collision to secure the safety of vehicle occupants.

DENSO's newly developed system main relay reduces operation noise by approximately 10 dB by using a structure that lessens the impact when a movable part comes into contact with a fixed part, without slowing the speed in shutting off the high electrical voltage in a collision. DENSO also reduced the number of components used in the product, making assembly easier.

In addition to DC-DC converters, battery monitoring units, and system main relays, DENSO has developed several other hybrid components including boost converters for inverters, electric compressors and hybrid computers.

"By their nature, hybrid vehicles require more components, resulting in an increasing demand for components that are smaller, lighter and deliver higher performance," said Mineo Hanai, managing officer responsible for DENSO's Electric Systems Business Group. "Using our experience and expertise, we will respond to these demands by continuing to develop new technology and products for hybrid vehicles."

Japan-based DENSO Corporation, a leading global supplier of advanced automotive technology, systems and components, employs 104,000 people in 31 countries with global sales totaling US$26.2 billion for the fiscal year ended March 31, 2005. In the Americas, DENSO employs more than 15,000 people at 33 companies with sales for the above fiscal year totaling US$5.4 billion. DENSO International America serves as DENSO's North American headquarters. DENSO common stock is traded on the Tokyo, Osaka and Nagoya stock exchanges. For more information, go to http://www.globaldenso.com/ or visit http://www.densomediacenter.com/ .