Mura R.,Center for Automotive Research |
Mura R.,Polytechnic of Milan |
Utkin V.,Ohio State University |
Onori S.,Clemson University
IEEE Transactions on Control Systems Technology
This paper addresses the problem of finding a closed-form optimal solution for the energy management problem in charge-sustaining hybrid electric vehicles (HEVs), and proposes, for the first time, a generalized stability and optimality framework for this type of problem. The energy management problem, which by its very nature is a finite-time horizon control problem, is reformulated as a nonlinear-nonquadratic infinite-time optimization problem, leading to a family of state-feedback control laws that provide optimality with respect to an infinite time horizon performance objective, while guaranteeing asymptotic stability. The stability problem in charge-sustaining HEVs is formulated to allow the design of analytical solutions using a Lyapunov-based argument. The proposed control law is implemented on a pre-transmission parallel hybrid heavy-duty vehicle and the performance of the closed-loop system is shown in simulation and compared with the benchmark solution provided by Pontryagin's minimum principle (PMP) and the real-time adaptive controller adaptive-PMP. Results show low sensitivity to the control parameter, low-calibration effort, and reduction of computational effort, while maintaining close-to-the-optimum performance. Hardware-in-the-loop simulations were conducted to validate and verify the new strategy in a real-time simulation setup. © 2015 IEEE. Source
Deptula L.,Center for Automotive Research
SAE Technical Papers
The approaching corporate average fuel economy (CAFE) regulations will again increase with new model years (MY). The U.S. Government finalized a regulation requiring cars and light trucks average 54.5 mpg fuel economy for MY2025. Vehicle manufacturers recognize removing weight is a key feature to meeting their targets for fuel economy and emission reductions. One common OEM strategy is the implementation of incremental weight reductions to attain these goals. The automotive industry continues to look for opportunities to reduce weight and cost while continually increasing performance and safety. Lightweighting technologies enhance vehicle performance, (fuel economy, acceleration, braking and emissions). New materials are available to reduce weight; however the incremental cost for the weight reduction can be prohibitive. This study will encompass the utilization of lightweight materials, as well as current and evolving manufacturing processes. Where reducing weight while achieving performance targets for dent resistance, stiffness, and crash-worthiness are the goals; the key is to attain a lightweight assembly that assists in meeting the fuel economy targets, through optimized part design and/or material substitution. Determining the cost to meet incremental light weighting objectives should be standardized using the cost per pound saved unit of measure. Previous studies have been conducted estimating that weight reductions using higher strength steels can cost 50 cents per each pound reduced, with claims that savings from substituting aluminum can cost $1.50-2.00 per pound saved. Automotive manufacturers estimate the cost of reductions could reach as high at $7 per pound reduced, while federal regulators estimate a significantly lower cost. Our objective is to address this discrepancy between these cost estimates for lightweighting. Current methods of measuring the cost of lightweight are often done through a piece cost evaluation in $/lb, or $/Kg. Another method includes evaluating costs from a tear down know as bottom up estimation. We will also evaluate how changes in lightweighting strategies affect direct manufacturing cost (DMC). We will examine the direct manufacturing costs to determine the cost feasibility to manufacture lightweight vehicle closures (doors, hood, and decklids). We wish to determine the manufacturers' cost impact caused by rapid change in adaptation of incremental lightweighting materials and processes applied to vehicles as opposed to mature manufacturing practices. The research will focus on methods used to create automotive closures. We will evaluate closure case studies, showing the cost factors of using different materials and processes evaluating the savings in weight compared to a baseline closure. We will explain our method of cost estimation to achieve light weighting in a way to better evaluate cost to meet these regulations on fuel consumption and emissions across the auto industry; to better inform the industry and regulators of the true cost of reducing the mass of automobiles. Copyright © 2015 SAE International. Source
Crawled News Article
The emissions scandal was a public relations nightmare for Audi and its parent company, Volkswagen AG. Despite the still-undetermined loss of brand loyalty the automaker suffered as a result, Audi's craftsmanship just received huge praise from Consumer Reports when the consumer watchdog group released its 2016 rankings of automotive brands. Audi was Consumer Reports' top pick of the 30 best automakers, besting Lexus, Porsche, BMW and Subaru. And 2016 wasn't the only year Audi got things right, according to Jake Fisher, Consumer Reports director of automotive testing. "We're seeing consistency over the last several years of Audi getting it right," says Fisher. "They're combining good reliability with good performing vehicles, and that's why they're on top.'' While Audi was honored as the best brand of the bunch, regulators are still investigating several of its vehicles, such as the Audi A3 (model years 2009 through 2015), for fabricated emissions tests. It was discovered last year that Volkswagen used sophisticated defeat devices in vehicles from several of its brands. That software throttling tuned the vehicles to run well within the Environmental Protection Agency's emissions standards while the automobiles were being tested, covering up the fact that they'd emit up to 40 times the acceptable amount of nitrogen oxides when not under the microscope of an emissions test. As a result of the emissions scandal, Volkswagen was sued by the U.S. Department of Justice and was forced to recall half a million Volkswagen and Audi vehicles. The top honors should be a huge help for the Audi brand, said David Cole, chairman emeritus of the Center for Automotive Research. Despite taking a hit, "Audi hasn't borne the brunt of what happened," Cole said. While the the rankings may help Audi, it could bruise a few other brands such as brands in Fiat Chrysler's fold. Here's how Consumer Reports ranked the entire field of 30 with the brands' overall score:
Crawled News Article
« City of Montreal signs a framework agreement for the purchase of Nissan LEAF EVs for municipal fleet | Main | Tesla unveils Model 3; delivery by end of 2017; already 115,000 reservations placed » A 20-kilowatt wireless charging system demonstrated at Department of Energy’s Oak Ridge National Laboratory has achieved 90 percent efficiency and at three times the rate of the plug-in systems commonly used for electric vehicles today. ORNL’s power electronics team achieved this world’s first 20 kW wireless charging system for passenger cars by developing a unique architecture that included an ORNL-built inverter, isolation transformer, vehicle-side electronics and coupling technologies—all in less than three years. For the demonstration, researchers integrated the single-converter system into an electric Toyota RAV4 equipped with an additional 10 kWh battery. Convenience and simplicity are at the heart of the ORNL system, which places a strong emphasis on radio communications in the power regulation feedback channel augmented by software control algorithms. The result is minimization of vehicle on-board complexity as ORNL and partners pursue the long-range goal of connected vehicles, wireless communications and in-motion charging. While the team’s initial focus has been static, or motionless, wireless charging, the researchers also evaluated and demonstrated the system’s dynamic charging capabilities. This ability can help accelerate the adoption and convenience of electric vehicles. Industry partners from Toyota, Cisco Systems, Evatran, and Clemson University International Center for Automotive Research contributed to the technology development demonstrated today at ORNL. The researchers are already looking ahead to their next target of 50-kilowatt wireless charging, which would match the power levels of commercially available plug-in quick chargers. Providing the same speed with the convenience of wireless charging could increase consumer acceptance of electric vehicles and is considered a key enabler for hands-free, autonomous vehicles. Higher power levels are also essential for powering larger vehicles such as trucks and buses. As the researchers advance their system to higher power levels, one of their chief considerations is safety. Energy Efficiency and Renewable Energy’s Vehicle Technologies Office provided funding for this competitively-selected project as part of a broad portfolio in support of DOE’s EV Everywhere Grand Challenge, which aims to make plug-in electric vehicles as affordable to own and operate as today’s gasoline-powered vehicles by 2022. Toyota provided several vehicles for the research, including RAV4s, a Scion and a Plug-in Prius. Other members of the ORNL project team are current staff members Steven Campbell, Paul Chambon, Omer Onar, Burak Ozpineci, Larry Seiber, Lixin Tang, Cliff White and Randy Wiles as well as retired staff members Curt Ayers, Chester Coomer and John Miller. The research and demonstration took place at ORNL’s National Transportation Research Center, a DOE User Facility.
Crawled News Article
Toyota and Clemson University recently unveiled a new all-electric concept car — dubbed the “uBox” — at the 2016 SAE World Congress, according to reports. The new electric vehicle concept was designed and handbuilt by graduate students at Clemson University’s International Center for Automotive Research — following a 2-year tour with Toyota Motor North America engineers and designers. The uBox concept — which resulted from a Clemson University and Toyota collaboration (dubbed Deep Orange) — is designed around the featured compact, dual-purpose, all-electric powertrain. The Toyota Executive Program Manager, Craig Payne, commented on the unique pultrusion technique utilized by the students (allowing composite carbon fiber rails bonded with aluminum to support a curved glass roof): “The roof pultrusion was something unexpected and very interesting when they first started talking about the concept. The fact that they were able to achieve an industry-first manufacturing technique as students speaks volumes for this program.” Toyota provides further information on the uBox: * A bold, youthful and distinctive exterior design that aligns with generation Z’s personality trait to stand out, embodying a muscular stance that looks like it’s sprung forward in motion, even when standing still. * A versatile interior that can be rearranged for various activities, from working or operating a business, to hauling bulky cargo. A low floor allows for reconfigurable, removable seats on sliding tracks that can be nested. * Vents, dashboard display bezels and door trim that can be personalized and made with 3-D printing technology, and an online community for owners where they can share design ideas. Drive an electric car? Complete one of our short surveys for our next electric car report. Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.