Jul 21, 2021


Achieving carbon neutrality through energy management for a mobility-centered society

Controlling cars as groups to optimize entire energy in cities

  • Thermal Management Systems R&D Div.Yu Ofune

    Yu Ofune studied mechanical systems at university and has pursued fundamental research in computational fluid dynamics (CFD). After joining DENSO in 2004, he took charge of development and design of new exhaust-system heat exchangers. He has been involved in developing thermal management systems since 2017, particularly those for electric vehicles.

  • Systems Development for Smart City Div.Mitsuharu Higashitani

    Mitsuharu Higashitani studied optimization algorithms at university and began working at DENSO in 2007. He currently develops system control architecture and standardized system simulators to facilitate implementation of energy management applications, thus helping to build the foundations for vehicle EMS.

Battery electric vehicles (BEVs) are just beginning to spread in Japan. The next decade or two is expected to bring about a revolution in transport systems, encompassing automated driving and other such advances, and in this new era people will demand different things from their cars. The core architecture of automobiles will change, transforming them from discrete products into optimizers for society as a whole. Let’s explore this new era of the automobile from the viewpoint of energy management.

Contents of this article

    From individual car optimization to society optimization

    — As automobiles evolve, so does energy management. The main focus of energy management systems (EMSs) in gasoline vehicles powered by internal combustion engines (ICEs) is the air conditioning system used to keep the cabin comfortable, but with BEVs energy management must be carried out for the entire vehicle as a whole. In other words, the job of the EMS is increasingly to ensure that the car serves the user’s needs. As we approach the era of the automated-driving car, what role do you expect energy management to play?

    Higashitani: In addition to automated driving, I expect other technologies that use information from outside of the vehicle—factors in the outside environment such as weather, road and traffic conditions—will become commonplace. This will require coordination with a wide variety of automotive-use applications.

    The EMSs we are currently developing use electronic control units (ECUs) to gather information from inside and outside of the vehicle, and as the amount of information from outside of the vehicle increases, these ECUs will have to handle more complex and massive amounts of information. At some point, it will become necessary for cloud networks to handle the information processing instead, and then give suggestions and orders to the car’s system. That’s how I envision the future of automobile operations.

    ― So EMS will do more than simply optimize operations for individual automobiles?

    Higashitani: That’s right. Energy management will focus less on individual cars and more on optimizing how society works as a whole. In any given city, we will see cars traveling on surface roads as well as expressways, and vehicles transporting both cargo and human passengers. These will include not just BEVs but also hybrid vehicles and fuel-cell vehicles.

    As automated driving technologies spread, we will have to think of cars in terms of groups rather than individual units. The challenge will then be how to operate these groups in ways that minimize CO2 emissions, in order to achieve a carbon-neutral society. So we need to consider what kinds of information should be gathered from the environment outside of the vehicle, and how to communicate with and between vehicles. We must define and solve each of these challenges one at a time.

    At DENSO, we made a video to show our vision of the near future.In this future society, users will board a vehicle and tell it their destination. During the journey, the vehicle will use artificial intelligence (AI) to optimize the in-vehicle environment based on users’ personal preferences and bodily conditions—creating the ideal environment for them to get some work done or take a nap, for example. Our ultimate goal for the future is to achieve a transportation infrastructure that tailors in-vehicle environments to user needs and preferences while optimizing energy usage for the city as a whole.

    Energy management will apply not just to individual vehicles, but also to urban areas as larger systems

    ― What kind of research are you doing to control vehicles as groups rather than just as discrete units?

    Ofune: One area is extending battery life and shortening charging times in BEVs through temperature control, vehicle speed adjustments and other such measures. There are also ways to improve fuel efficiency in hybrids, diesel vehicles, and hydrogen fuel cell vehicles by changing driving styles.

    A lot of this research centers on driver support mechanisms that extend battery life, optimize fuel efficiency and achieve other such improvements in individual vehicles. By integrating this type of energy management into transport management services, we believe that we can benefit society as a whole.

    Higashitani: Another part of our research is seeking solutions to problems faced by bus and truck operators. If you own a bus or truck company, you can’t simply replace your entire fleet of dozens or hundreds of vehicles with BEVs. Rather, you might try introducing 10 BEVs to start with, and if things go well, maybe add 20 or 30 more in the next round of replacements, gradually transforming the fleet. You could even mix in some hybrid vehicles or diesel-powered vehicles.

    In order to achieve a high operating rate of 80 percent for your fleet, you have to think about which vehicle types are suited to which tasks and assign them accordingly. For example, when operating along routes with few charging points, diesel-powered vehicles make more sense than BEVs. Also, when using BEVs, charging a large number of vehicles at once would lower your operating rate, so you’ll need to stagger charging sessions. There are so many different factors to consider.

    By integrating EMS into this type of setup, it becomes possible to expand your business. That’s what my division is pursuing, and we are currently carrying out demonstration tests as part of the development process.

    Group control of cars on public roads by 2030

    — In 2014, the Japanese government established an intelligent transportation system (ITS) initiative. However, it seems that sophisticated vehicle control technologies such as automated driving will require infrastructure improvements.

    Higashitani: For a period, various corporations and research organizations were conducting R&D on ways and ideas for improving the infrastructure. However, few people had a clear vision of how these infrastructure improvements would be implemented, or what types of services would be offered.

    In contrast to Japan, companies in China and some other countries have been very quick in their proof-of-concept (PoC) efforts, and have already implemented improvements and technologies in BEVs and other vehicles. Furthermore, they carry out over-the-air (OTA) updates and additions to fix product bugs and malfunctions. This is fast becoming the standard approach in the auto industry.

    ― Traditionally, the auto industry determines the specifications at the start, then proceeds from the upstream to downstream stages using a waterfall-type development model. Do you think this approach is starting to change?

    Higashitani: Certainly. I think we could learn from the “agile development” approaches used at Chinese companies and elsewhere, because it enables more nimble and flexible development. My team is currently pursuing R&D based on this approach.

    We start out by simply making what we want, and then evaluate it after it’s made. If we think the results could be useful to end users, we begin developing the necessary elemental technologies. Some people start with elemental technologies first, but this approach does not take user value and needs into account, so it’s ineffective.

    Creation and testing of a prototype system

    The role of DENSO engineers

    — Modern-day automobiles have countless sensors, ECUs and other such components, making software development an increasingly central part of the product creation process. Since both of you are involved in EMS development, could you tell me how it differs from software development?

    Higashitani: Put simply, I think the scope of things we have to take into account is much wider. The standard method for controlling each individual component is a proportional–integral–derivative (PID) control loop, in which input values, output values and target values are calculated using a combination of proportional, integral and derivative functions. Moreover, control must be accomplished with extremely high precision.

    There are numerous possibilities when it comes to system control: operating component A in one way may cause component B to operate in another, but operating component A in a different way may cause component C to respond. In this way, we think about how individual components and subsystems function within the entire framework based on an understanding of overall system characteristics.

    ― What were your original areas of specialization?

    Ofune: I originally studied mechanical systems. At DENSO, I spent a long time designing and developing heat exchanger devices. They then began sending me to automakers to work on thermal management systems, and through that work I began thinking about how to better control heat throughout the vehicle as a whole, and also what kinds of new value we could offer customers by gathering and using information from the outside environment.

    Higashitani: I started out in electrical systems, and at DENSO my main task was to deeply analyze how hybrid vehicles use electric power, and then apply what I had learned to optimize energy use for the vehicle as a whole.

    ― So you developed a better understanding of individual components while creating architecture that enables systems to perform more optimally?

    Higashitani: In order to achieve optimized system control, it’s important to sometimes let go of things that are not that important. One example is rounding parameters with no effect on safety performance to more easily workable numbers, thus reducing the calculation workload for the central ECU. We must not view the system as a black box whose contents are unknown; in contrast, we need to approach it as a “white box” made with components whose characteristics and workings we understand.

    By the way, because Mr. Ofune is a thermal management expert, when I worked with him on system development I had to spend a lot of time studying heat-related mechanisms in order to keep up.

    — In recent years, we’ve seen connected technologies emerge, linking together automotive systems with cloud networks and other outside elements.

    Higashitani: That’s right. It’s important these days to think about specific roles and influences within the overall optimization process. For example, even when controlling vehicles as a collective group rather than discrete units, certain things must still be left to individual vehicles. Even if you find an approach that optimizes energy use for the group, if a cat jumps out in front of one of the cars, that car must react as an individual unit and apply the brakes.

    That’s our job—to think of such factors as well as the division of functions within the whole, and then decide on system models accordingly.

    ― As software becomes an increasingly central part of automobiles, what is expected of engineers in the industry?

    Higashitani: Within the category of “software engineers,” there are all sorts of different jobs. Some people develop system control mechanisms, while others just code all day. These days, I think engineers are expected to be able to put together control mechanisms.

    As one of my coworkers said to me, a truly outstanding engineer is one who understands the bigger picture of what needs to be done, and then breaks down and organizes this in a hierarchical manner. While building the system, that engineer must also structure the software to make it easier to apply improvements in the future.

    ― So past experience in automobile-related development is not a prerequisite?

    Higashitani: It’s not, because it takes the same essential skills and knowledge to understand automobile systems that it takes to broadly grasp software architecture in general. People who have solid experience with software architecture are often able to transition easily into the automotive system development field.

    ― Many people say we are currently experiencing a once-in-a-century revolution in the auto industry.

    Ofune: Yes, and it’s like a crisis. DENSO can’t simply continue manufacturing physical products as automakers did before if they hope to survive in the industry. We have to look toward the future and evolve our products further.

    Higashitani: As BEVs increasingly become the standard, I think automakers will reposition themselves within the industry, and competition will intensify. We will probably see new startups emerge in the industry, and they will become key players. Therefore, it’s important to offer forward-looking product value first before other companies, and quickly integrate it into systems.

    Ofune: DENSO’s main business is selling products, so clearly it’s important to focus on developing truly good products to sell. We need to become a company that doesn’t just sell traditional products, but expand our business so we can offer energy management technologies and other new things. That’s what we are pushing ourselves to do right now.


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