German carmakers agree on 48V on-board supply, charging plug
At the 15th Automobil Elektronik Kongress in Ludwigsburg, the companies announced to establish a 48 V supply network supplementing the current 12 V supply. They also said they agreed upon measures supporting CAN bus network segmentation and a common charging plug as a joint de-facto standard.
"At a growing extend, high-current loads are utilized in the vehicles," said Volker Wilhelmi, Head of Electrical/Electronic on-board networks for Daimler. "It becomes increasingly difficult under technological and cost aspects to implement these functions and devices in a 12 V supply network." For this reason, E/E engineering managers of the five OEMs agreed to implement a supplementary 48 V supply in future car generations. Both subnets will be connected through a bidirectional DC/DC converter. "This enables us to integrate high-current devices into our cars at lower cost, better quality and more easily", Wilhelmi said. In particular, the 48V option will improve power recuperation in electric and hybrid electric vehicles and thus reduce CO2 emissions. In addition, powerful actuators can be implemented at smaller form factors. Also heating and air conditioning could benefit from the higher operating voltage.
In their statement the OEMs made clear that they all are developing 48V components and requested the semiconductor providers and control unit manufacturers to actively join the development process for serial production. However, no timeline was provided.
The implementation of an additional 48 V supply network in the vehicles translates in major design challenges for suppliers across the value chain. In particular, providers of semiconductors and ECUs will be affected – they need to adjust their product range to the higher voltage and in part re-design their products. However, no semiconductor manufacturer contacted by eeNews Europe was able to comment.
The second part of the announcement referred to the CAN data bus. The OEMs agreed that in specific situations it should be possible that only parts of the data bus are activated. The OEMs — for this part of the announcement they were joined by Burkhard Milke, top E/E manager for GM subsidiary Opel — said they will make arrangements to support partial bus operation. "This is about saving energy", said Rick Hudi who oversees E/E development at Audi. "We estimate that thus we can reduce current by about 10 A which will translate into fuel savings of some 0.1 liter per 100 km".
On behalf of the group, Volkswagen E/E top dog Volkmar Tanneberger introduced a common power plug for electric vehicles. This so called Combo plug aims at DC charging and is backwards compatible with the earlier Type 1 and Type 2 designs. These designs have already been introduced in the industry; Type 1 originated in Japan while Type 2 is a European development. Tanneberger said that the proposal has been coordinated with U.S: OEMs as well as the SAE. According to Tanneberger, the OEMs agreed to include powerline communications schemes into their new standards proposal. "Data communication is a very important aspect in this context," Tanneberger said.
According to the VW manager, the new plug is scheduled for roll-out already in first quarter of 2013. In this context Tanneberger appealed to China’s automotive OEMs to join the standardization process.
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