DENSO Develops New Components for Hybrids
03 April 2006
|
| DENSO DC-DC converter. |
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. Toyota is using these components in the new GS 450h hybrid.
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 air-cooled instead of the conventional method of water-cooling, allowing more flexibility in installation location.
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% smaller and approximately 50% lighter than conventional products.
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.
DENSO has developed several other hybrid components including boost converters for inverters and electric compressors.
Although the relevant technical info isn't yet available for the GS450h, the DC-DC converter will probably now be mounted inside the battery pack enclosure, as it is for the Camry hybrid (which undoubtedly shares the same Denso converter). Freed from the converter, the up-front liquid-cooled inverter can now shrink in size, as well.
Toyota's 1996 RAV4EV had an inverter assembly that took up most of the engine bay. The latest generation Lexus/Toyota inverters are about the size of a 12V automotive battery, and Toyota promises to make the next generation smaller yet.
Posted by: Jack Rosebro | 03 April 2006 at 05:26 PM
Well stated. Also just to add, a large part of space that is taken up in terms of the hybrid system is the battery pack, which typically lowers trunk space considerably. Toyota's move to Lithium-Ion batteries will result in a dramatic reduction in size for the battery pack, not to mention higher energy density, and more efficiency compared to NiMH. Together with smaller electric motors, smaller inverters, and just about everything else on a smaller scale, Toyota's 3rd gen HSD will be a flexible system that should take up minimal space in sedans, and virtually no space at all in bigger vehicles.
Posted by: toyo | 03 April 2006 at 09:47 PM
Can't wait to see the third generation of HSD, I am banking on it being as dramatic an improvement as my 2nd gen was over the first.....I will be very suprised if it isn't plug in.........
Posted by: Bud Johns | 08 April 2006 at 10:21 AM