BMW and Siemens Car2X System Transmits Data Between Traffic Lights and Vehicles to Optimize Stop-Start Function
During the AASHTO conference (American Association of State Highway and Transportation Officials) in Palm Desert, California last fall, BMW and Siemens presented a system that transmits data between traffic lights and the vehicle to optimize the automatic engine start-stop function and the recovery of braking energy when approaching a traffic light.
Current vehicles use sensors to constantly gather information about such things as speed, the environment, or the traffic ahead. Networking the cars makes it possible to warn the vehicles behind about icy roads, traffic jams, or similar situations. Intersections and multilane roads will become safer if the cars all keep an eye on one another. Energy efficiency also improves. Fuel consumption can be reduced even further if the automatic engine stop-start system from BMW EfficientDynamics knows the traffic signal cycles.
The function presently switches the engine off as soon as the car is stationary and the driver releases the clutch, with the engine restarting when the clutch is depressed. If there are only a few seconds between stopping and starting, however, it is more energy efficient to let the engine run.
At the same time, vehicles could send back information to the traffic light, e.g. position, direction and speed of the car, which can be used to optimize the traffic flow and to adapt the cycle time of the traffic light.
The improved networking of cars among themselves and with traffic lights or warning signs is expected to make road traffic more efficient. The exchange of data on traffic density, road conditions, or traffic signal cycle times enables traffic to flow more freely and also makes it safer.
This information is particularly important for optimal energy management in electric cars. With Car2X communication, vehicles communicate either with other vehicles (Car2Car) or with the traffic infrastructure (Car2Infrastructure).
Car2X communication also turns cars into mobile sensors for traffic management systems because they provide up-to-the-second data about the traffic situation.
Among the things under development by Siemens Corporate Technology (CT) are efficient communication protocols with which the data can be transmitted within just a few milliseconds to all partners in the surrounding area. The company is also working within the Car2Car Communication Consortium to develop standards that ensure that all makes of cars and the infrastructures can “talk” with one another without problems. Siemens is also developing prototypes of the communication units.
Siemens is currently the only company that can offer integrated solutions for both vehicles and traffic infrastructures.