Toyota Tests Hybrid Technology For More Efficiency

Japanese carmaker Toyota is testing new technology to make its hybrid and electric cars even more efficient.

A year-long trial in Japan will evaluate the performance of new power semi-conductors, that use a silicon carbide (SiC) material, that will be fitted to a Camry hybrid saloon prototype and a hydrogen fuel cell-powered bus.

The technology

Power semiconductors are found in the power control units that govern the motor drive power in hybrids and other vehicles that use an electric powertrain.

These units manage the use of electricity, sending power from the battery to the motors when the car is being driven, and recharging the battery when the car is braking or decelerating.

The type of semiconductors used currently account for about 20 percent of a vehicle's electrical losses, so making them more efficient is potentially a good way to increase the efficiency of the complete powertrain.

Compared to the current silicon power semiconductors, the new, high-quality SiC type create less resistance when electricity flows through them.

The technology has been developed jointly by Toyota, the Denso Corporation and Toyota Central R&D Labs, as a result of a broader research and development project.

The test project

In the Camry hybrid prototype, Toyota is installing the SiC power semiconductors in the PCU's internal voltage step-up converter and the inverter that controls the motor. It will collect data, including PCU voltage and current, driving speeds, patterns, and conditions, such as outside temperature.

By comparing this information with data from the silicon semiconductors currently in use, Toyota will assess the level of efficiency improvement achieved.

The Camry road test will take place mainly in Toyota City over a period of about a year from early February.
Toyota has also recently started collecting operating data from a fuel cell bus that is in regular commercial operation in Toyota City.