Hitachi Develops Communication Technology for Large-Capacity DC Power Lines for Vehicles-Contributing to Weight Reduction and Fuel Efficiency Improvement

Hitachi and Hitachi Automotive Systems have individually installed ECUs (Electronic Control Units) in powertrain systems, which consist of devices such as engines and transmissions in vehicles, as well as multiple sensors and actuators. The company announced that it has newly developed a large-capacity DC PLC (Power Line Communication) technology for vehicles that integrates and shares the connected wire harnesses and enables network connection.

This technology can also be applied to electrified vehicles, reducing the weight of automobiles by reducing the wire harnesses of powertrain systems, and contributing to improved fuel efficiency.

Comparison of the conventional connection method modeled on the HEV (Hybrid Electric Vehicle) and the connection method using the new technology developed this time.

The power line communication technology developed by Hitachi and Hitachi Automotive Systems this time is “automatic network configuration technology” that facilitates network connection between the powertrain integrated ECU and the wire harness that connects sensors and actuators, and a large current sends a signal. It is composed of “noise avoidance technology that enables stable communication” that does not interfere.

In the former “automatic network configuration technology”, by detecting the difference in wiring resistance depending on the connection position of the sensor and actuator, the connection position on the network can be automatically grasped and each sensor or actuator can be identified. .. Therefore, the wire harness can be shared and connected to the network, and the amount of the wire harness can be reduced.

On the other hand, in the latter “noise avoidance technology that enables stable communication”, a power line communication circuit that adjusts the switching timing of the MOSFET is arranged so as to avoid a large current flowing at the timing when a signal flows through the power line. This avoids noise before and after the timing when the signal flows through the power line. As a result, the error rate of communication is reduced, and stable communication is possible even on a power line in which a steep current change occurs.

By using these technologies, the total length of the wire harness that connects the powertrain integrated ECU and each sensor and each actuator can be reduced, the weight of the wire harness can be reduced by about 40% compared to the conventional connection method, and the weight of the automobile can be reduced. Contribute to the conversion.

Furthermore, by distributing the MOSFETs not in the ECU but on the sensor and actuator side, the heat generation of the powertrain integrated ECU is reduced by about 60% compared to the conventional connection method, and natural cooling is possible. In addition, the automatic network configuration technology eliminates the need for configuration and design changes to connect sensors and actuators to the ECU, so when changing the type or number of sensors or actuators, the ECU is reconfigured or reconfigured. It also contributes to the reduction of the development process because it enables the development of vehicle models without the need for design.

The technology is scheduled to be announced at the “Autumn Convention of the Society of Automotive Engineers of Japan held at the Osaka International Convention Center” from October 11th to 13th.