The ‘Electrification Factor’ in Transportation
Coolness’ and performance serve the market, and green goals
By Ali Emadi, IEEE Transportation Electrification Initiative, Director, McMaster Institute for Automotive Research and Technology
The full version of this article was originally published in EE Times
Electric vehicles (EVs) currently on the market represent a beneficial new direction in terms of sustainable, low-impact transportation. Yet the EV market today tends to obscure a much bigger picture as we pursue the “electrification of transportation.”
My colleagues and I are focused on gradually increasing what we call the “electrification factor” in all forms of transportation, which includes passenger cars, but extends to trains, boats and planes. When terms such as “electrification factor” and the “electrification of transportation” are defined, a much bigger picture emerges.
So let’s begin with definitions and their implications. Then we’ll look behind the curtain at the technological hurdles we must clear in the pursuit of these objectives.
The “electrification factor” may be defined as a percentage of the onboard electric power to a vehicle’s total power. Let’s use the familiar passenger car as an example. With no electric load onboard, a vehicle’s electrification factor is zero. When all functions are accomplished electrically, including propulsion, the electrification factor is 100 percent. Most passenger cars on the market today possess an electrification factor in the single digits. Today’s electrified vehicles might register in the low- to mid-double digits, depending on the model.
To increase the electrification factor, for instance, we might replace hydraulic power steering with electric power steering. We can electrify the air conditioner. A number of mechanical or hydraulic pumps can be replaced with electrical systems. An integrated, electric starter/generator can replace separate, discreet units and that too contributes to increasing the electrification factor.
Stepping back, an auto has four different, power transfer systems: electrical, mechanical, pneumatic and hydraulic. Electrical systems, generally, are the most efficient. And they can be monitored and communicated with more effectively than the others, which means they can be optimized and controlled for efficiency and performance.
Electrifying non-propulsion loads raises the electrification factor in modest increments up to perhaps 15-20 percent. Electrifying a vehicle’s mode of propulsion produces a much greater electrification factor, reaching as high as 50-70 percent in hybrid electric powertrains and near 100 percent in all-electric vehicles. Based on back-of-the-envelope calculations, I’d suggest that the average electrification factor for new vehicles manufactured worldwide today is only about 5-10 percent.
Our goal for what I call “Transportation 2.0,” of course, should be to increase the electrification factor as much as possible, as quickly as possible. This is because electrification takes advantage of a highly efficient form of energy transfer and because the electrification of a vehicle’s various systems increases performance, including acceleration, maneuvering, braking, safety and fuel efficiency.
The ‘coolness’ factor
Increases in efficiency and performance, in turn, provide the basis for more attractive and innovative vehicle designs, which increases what I like to call the “coolness factor.”
Arguably, the “coolness factor” is what sells cars. One could argue – and some do – that everyone should immediately buy an all-electric vehicle because it’s good for the planet. But, so far, that argument hasn’t produced significant uptake of EVs that supporters hoped to reach by this point.
That’s why I argue that incremental increases in the electrification factor will produce a strong, tide-like pull on the market, producing cooler, higher-performing, more efficient “electrified” vehicles that consumers really want to buy. That in turn will produce economies of scale and, thus, lower costs, which enable higher electrification factors across the worldwide fleet. I call the incremental approach “more-electric vehicles,” or MEVs.
This market-based approach should also increase the interest in electrification by auto manufacturers, which must produce cars that people want to buy. As we’ve seen, simply claiming that a particular car purchase is “good for the planet” has not significantly moved the proverbial needle. A dedication to incrementally and consistently raising the electrification factor in transportation will do more in the long run to reduce carbon dioxide and other greenhouse gas emissions than simply preaching about the virtue of all-electric cars.
Make no mistake about it, I very strongly believe in all-electric vehicles. However, since consumers purchase cars based primarily on emotional attachments and perception, the coolness factor in EVs is of significant importance. The good news is that electrified vehicles have tremendous opportunity to be cooler than conventional internal combustion engine (ICE) vehicles. Both engineering design and marketing to consumers must be done right. We’ll then see a far bigger uptake of EVs.
The long road ahead
Substantial increases in the electrification factor, however, will require us to travel a long road. What I call “Transportation 2.0” is a fundamental paradigm shift that will take years. The technological challenges are many and we are working on them with a broad array of stakeholders. I find it far more effective to work with OEMs (original equipment manufacturers) to increase the electrification factor over time than to berate them for not moving fast enough.
One important policy factor will aid our quest: new CAFÉ (Corporate Average Fuel Economy) standards will be doubled by 2025, from today. The efficiencies enabled by increasing the electrification factor will be an attractive path for OEMs to achieve this marked increase in fuel economy.
Let’s distinguish between two distinct opportunities to raise the worldwide fleet’s electrification factor. First, after-market efforts are increasingly focused on converting internal combustion engine vehicles – the installed base on the road today, which is perhaps one billion vehicles – to hybrid and plug-in hybrid and electric vehicles.
The low-hanging fruit in this case are large vehicles – the proverbial “gas guzzlers” such as pickup trucks, SUVs, vans, delivery trucks and busses. Conversions cost roughly half that of a new electric-drive vehicle. The conversion effort is being promoted by various government programs, partnerships and NGOs such as California’s CalCars.
The other big opportunity is to shift manufacturing of new vehicles to models with ever-higher electrification factors. New manufacturing accounts for perhaps 60 million passenger cars each year; that’s nearly 75 percent of all vehicles produced each year.
Obviously, addressing the installed base, comprised of older, less efficient vehicles that produce the most emissions, would produce huge environmental gains. Conversely, new vehicles contribute to the turnover of the installed base and represent a fundamental opportunity to “get it right” from the start, before a vehicle hits the road.
In both cases, however, we can make vast improvements in performance and reduce emissions by making incremental improvements. Targeting a vehicle’s propulsion system will result in big gains, but even a step-by-step process in that area will yield significant results.
A vehicle with an internal combustion engine has one electric motor that acts as a starter, and another electric motor that acts as an alternator. The starter cranks the engine. The alternator acts as a generator that charges the battery. The two could be combined – an electric motor could behave both as a motor and a generator, since the two roles don’t occur at the same time – into an integrated starter-alternator.
This hasn’t been done at mass scale yet because the sizes of the two machines are different. One is low-speed, high-torque, the other is high-speed, low-torque and combining them has not been cost effective. As we pursue an increase in the electrification factor, the alternator gets bigger and the opportunity arises to integrate it, too. The result is an integrated starter alternator or a battery starter generator (BSG).
Now we can target propulsion. When one stops for a traffic light, say the engine shuts off. When it starts again, say the BSG cranks the engine at a higher than traditional RPM (revolutions per minute) that results in efficiencies, better mileage and reduced emissions.
That’s the low end of electrification but we’re targeting propulsion. Add a second machine that can take turns propelling the vehicle and a hybrid results. It’s not all electric but it has a significantly higher electrification factor than the typical passenger car. Auto manufacturers are more comfortable with these incremental (yet significant) changes, they produce cost-effective products and that’s why we’re seeing hybrids sold at a growing rate.
What technologies need development to help realize the potential for raising the electrification factor in passenger cars and other modes of transportation?
The answer is not simple. That’s because the endeavor requires integrated, electromechanical design in the context of the application. Electrical engineers and mechanical engineers need to work together. Also, we need to bring down the cost of power electronics and electrical systems – that’s a difficult challenge.
In general, the mass commercialization of electric vehicles, hybrid electric vehicles and plug-in hybrid electric vehicles will require the development of power electronic converters, electric propulsion motors and controls that are low in cost, rugged and reliable, light in weight, low in volume, and scalable.
Technologies with unprecedented commercialization opportunities will require interdisciplinary teams (more on that angle in a moment), and include:
- Power electronics, motor drives, electric machines
- Advanced electro-mechanical powertrains, systems integration and thermal management
- Vehicle controllers and electronic control units (ECUs)
- Batteries and energy storage systems
- Energy storage systems’ electronic controls, management and packaging
- Hybrid battery/ultra-capacitor energy storage systems, and
- Vehicle-to-grid (V2G), vehicle-to-infrastructure (V2I) and vehicle-to-home (V2H) integration.
My own interdisciplinary team works in four main areas: power electronics and electric motor drives, electric machines and electromechanical powertrains, energy storage (mainly the battery pack, not the cell) and software and embedded controls.
Let’s look at these component technologies one at a time. Battery cells have been advanced through major investments over the past few years. However, we haven’t seen as much investment in the three other areas, especially power electronics and electric machines.
In the area of power electronics, our focus is on an integrated approach that considers electrical, mechanical, thermal and manufacturing aspects right from the initial design stage. It’s simply not enough to have a power electronics circuit design with power semiconductor devices. Mechanical aspects of packaging and components placement as well as cooling and thermal management systems must be considered simultaneously. We are also fortunate to have manufacturing experts embedded with the design and development team to guide low-cost manufacturability. The goal is to develop cost-effective, reliable, lightweight and compact DC/AC inverters, DC/DC converters and AC/DC chargers that are scalable for a specific range of products. We’re taking the same approach to electric propulsion motors and electromechanical hybrid and electric powertrains.
In addition, design in the context of the application and optimization at different levels (not just components and subsystems, but at the system level as well) is of significant importance. For example, in a hybrid electric powertrain with two electric machines, two power electronic converters, an ICE, a transmission, a battery pack and multiple control units with embedded software, system optimization is exceptionally complex. But it will result in superior cost-effectiveness, system efficiency and performance.
My team also works on the battery pack, which contains the cells. Battery packs include battery management systems (BMS), electronics, balancing, protections, thermal management and packaging. Hybridizing battery packs with ultra-capacitors to improve performance and increase the life of the battery pack is of great interest, especially in heavy-duty vehicles.
Developing reliable and fault-tolerant software and embedded controls is also critically important. In addition to the overall powertrain controller, software is critical in powertrain components including motor controls, power electronics controls and energy storage systems controls. Charger controls and interfaces with the grid also need embedded software.
Knowledge, Skills and Abilities
Beyond the technology challenges, the education, training and professional development of multidisciplinary engineers is just as critical to advancing the technology for the electrification of transportation. We need electrical engineers, mechanical engineers, software engineers, controls engineers, power electronics engineers, electric machine designers and battery specialists. All of these specialists must have an aptitude for working across other disciplines.
We simply aren’t educating enough students in these various disciplines in general and, thus, it’s not surprising we have a shortage of all of them in the automotive industry, in particular.
Core technologies, across platforms
For simplicity’s sake, we have used the passenger car as our example. But land vehicles run the gamut from e-bikes to three-wheelers to passenger cars, busses, trucks, heavy equipment, trains and more. In fact, the electrification of transportation has implications for transportation modes across land, sea, air and even space.
These are not wholly discreet and disparate markets, from the point of view of technology development. Technologies initiated for aerospace applications have been driven down into land vehicles, for instance. The applications and specific technologies may differ, but many of the fundamental principles are shared across land, sea and air transportation platforms. A coordinated approach to the challenges will contribute to reducing costs through economies of scale.
For instance, efforts might be segmented by application, so that electric motors might be developed in the 5 to 10 kilowatt range, from 10 to hundreds of kilowatts, etc. Energy storage systems present similar cross-platform opportunities and our efforts should be segmented by scale and application.
Many readers might be tempted to view the electrification of transportation as a niche pursuit, but thousands of people around the world are working today on defining and meeting the technology challenges.
Related technologies and their applications are the focus, for instance, of the IEEE Transportation Electrification Conference and Expo (ITEC), which will be held in Detroit, June 15-18, 2014, and in Beijing, Aug. 31-Sept. 3, 2014. Everyone from engineers, managers and researchers to OEM and suppliers to interested consumers attend these annual events to keep abreast of developments and collaborate with colleagues. The events even hold educational boot camps for mechanical engineers interested in electromechanical topics, for electrical engineers interested in mechanical engineering and for software engineers interested in transportation electrification.
In sum, the electrification of transportation is coming of age. Increasing the electrification factor in our various modes of transportation should move markets. Consumers will be attracted to cool designs and performance and the value proposition of improved efficiency and performance in more utilitarian applications across larger vehicles as well as trains, boats and planes will draw institutional purchases.
The undertaking is enormous and will require entrepreneurs, academia, large corporations, small and medium sized enterprises (SMEs) and government involvement to succeed. The market will respond and, as a result, we’ll vastly reduce the emissions associated with internal combustion engines.
In addition to his duties at the McMaster Institute, Dr. Ali Emadi is the Canada Excellence Research Chair in Hybrid Powertrain and also a guest editor-in-chief for the IEEE Transportation Electrification Initiative, specifically aimed at accelerating the development and implementation of new technologies for the electrification of transportation.
Before joining McMaster University, Dr. Emadi was the Harris Perlstein Endowed Chair Professor of Engineering and director of the Electric Power and Power Electronics Centre and Grainger Laboratories at the Illinois Institute of Technology. Dr. Emadi is internationally recognized for his in-depth research on hybrid electric vehicle powertrains and electric drives having authored over 250 publications and conference papers, as well as several books.