Is a move to a 48 Volt power supply feasible?

Automotive IQ recently interviewed Professor Dr. Dieter Nazareth who is Professor of Computer Science at Landshut University of Applied Sciences and a Guest Professor at Shanghai Jiao Tong University. He is the chairman of the 3rd International Conference: Advanced Automotive Cabling. In this two part interview, we discussed the integration of more and more functionalities into vehicles as well as the feasibility of moving to a 48 volt power supply.

Part 1 of a 2 part interview:


Full Interview PDF: Part 1

"The problem is really that about 15 years ago we already had
that discussion and we invested a lot of money in that topic and it never came
and I'm not sure whether now it will be successful because it will be a huge step
to switch from 12 volt to 48 volt."

Automotive IQ: Dr. Nazareth, I'd just like to ask you if you could give a little bit of background on what you do.

Dieter Nazareth: My basic focus is automotive software engineering. I'm a computer scientist. I studied computer science and did my PhD in the area of formal software specification and then I joined BMW and that was the beginning of my passion for automotive applications and I've been basically working in that area for twenty years. Writing or working on the methodologies of how to develop software for control units. That is exactly my focus.

Automotive IQ: What do you see as the most challenging point in that particular area of the automotive industry, looking out one year then looking out ten years, if you could?

D.N.: The biggest challenge is the ever-increasing functionality of the vehicles. Every year we have more and more functions. When we look back twenty years ago, we had a few control units, maybe ten to twenty control units in a car; nowadays we have up to 100 control units in one car. The reason is that we have more and more new functions. For example, when we look at hybrid vehicles, we need an electronic control unit for the E-motor and in addition we need a vehicle control unit handling the interaction between combustion engine and E-motor. We have more and more safety or comfort functions, like automated parking, lane-keeping, drowsiness detection and so on. We are faced with a huge number of functions and the problem is it will get even worse because now we are at the point that the car is connected to the environment. So up to now the vehicle network was an isolated in-vehicle network. But nowadays we are working on car-to-infrastructure communication, car-to-car communication, in general it's called car-to-x-communication. So that means the vehicle will be part of a bigger network.

Automotive IQ: Functionalities related to remote diagnostics?

D.N.: No, not remote diagnostics. We are talking about car-to-car communication so my car can talk with the car in front of me and can exchange data because the car in front of me knows much earlier what is happening. So it can tell me the current situation of the road, for example, whether it's icy and if it tells me that, my car has this information and can react much more quickly on that.
Or car-to-infrastructure means the car communicates with a traffic management system in a city. So the traffic management system knows where all the cars are and tries to bring the cars through the city in the best way. Or traffic-light communication where the car can communicate with a traffic light and when it switches to red, it automatically stops my engine and restarts the combustion engine again before it switches to green. Why not?

Automotive IQ: Some small environmental gains are possible there.

D.N.: Yes. There are a huge number of ideas and when we look at that, everything is software.

Automotive IQ: Earlier today we talked about the potential move to 48 volts. Could you give your thoughts on that and if it's actually feasible or if we're going to have a repeat of ten or fifteen years ago where we talked about it and nothing really happened?

D.N.: The problem is really that about 15 years ago we already had that discussion and we invested a lot of money in that topic and it never came and I'm not sure whether now it will be successful because it will be a huge step to switch from 12 volt to 48 volt. There are two possibilities: either we have both voltage levels in one car, so then we have 12 and 48 volts which mean that we have to manage the isolation between 12 and ground, between 48 and ground, but also between 12 and 48. If we have different voltage levels we need a battery on both levels and a DC/DC converter to convert from 48 down to 12 volt. Everything's really, really complex. The other way would be much easier: to switch completely to 48 so there's only 48 in the car. But that requires that all electronic parts have to be switched to 48-volt level - everything in the car. So if you want to switch one car to that level then you cannot use any old parts anymore. So that means complete new development.

Automotive IQ: Everything gets replaced?

D.N.: We can start at the green field, totally from the beginning.

This is part 1 of a 2 part interview with Professor Nazareth

Read the conclusion of this interview here

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