It's Déjà Vu all Over again for powertrain engineers who are focused on improving fuel efficiency while maintaining performance, just as they were in the aftermath of the 1970's oil crisis. Only this time they have more sophisticated tools and are building better cars.
“When you compare the ownership and operating costs of a '69 Ford Mustang Mach 1 and an '07 Mustang GT, they're almost the same-even with the price of gas at $3 per gallon today versus 25 cents,” contended Joe Funyak, Automotive, Industrial and Multimarket business group product marketing manager at Infineon Technologies North America.
“Back then you could get 5-7 mpg city and maybe 12 highway, but owners didn't care, because they wanted power,” Funyak recalled. “Now they can get 17-18 mpg city and 25-26 highway, and there's no comparison in performance. The Mach 1 was fine going straight, but stopping or cornering was a challenge, and it was difficult to find a 6-CD changer in 1969. Today, an owner gets better mileage and performance, along with stability control, disc brakes and airbags. And electronics makes all of that happen.”
Infineon is collaborating with BMW on a new engine control unit for the next BMW M series based on 32-bit flash microcontrollers from Infineon's AUDO FUTURE family. The engine is expected to offer reduced fuel consumption and to meet a range of current worldwide automotive emissions standards, including EURO5 and US-LEV2.
Infineon's AUDO FUTURE MCUs include the 180 MHz TC1797 with 4 MB of flash and integrated FlexRay controller, the 133 MHz or 80 MHz TC1767 with 2 MB of flash, and the entry level, 80 MHz TC1736 with 1 MB of flash. The MCUs are based on the firm's TriCore processor architecture, which combines the capabilities of a microprocessor, a microcontroller and a digital signal processor on a single chip.
A MultiLink interface enables developers to connect multiple AUDO MCUs for data sharing at rates of up to 37.5 Mbps. On-chip peripherals are handled by a peripheral control processor engine, allowing the TriCore core to focus on engine management, transmission control and other powertrain functions.
The AUDO family also supports AUTOSAR software and includes a FlexRay communications block.
The newest AUDO processors offer up to 66% higher performance than previous AUDO products and are suited for OBD2 self-diagnostic functions such as emissions monitoring and emission standards such as EURO6 and Tier2 Bin5 in the US, according to Jochen Hanebeck, senior vice president and general manager of Infineon's Microcontrollers business unit. New emission standards require more complex algorithms and more performance, but Hanebeck said the embedded flash in AUDO FUTURE MCUs can accommodate all of the necessary code.
“Powertrain applications are the harshest of automotive electronic environments,” said Mark Fitzgerald, an automotive electronics analyst at Strategy Analytics. “Future vehicle emissions legislation and propulsion technologies will ensure that powertrain control remains one of the most challenging applications.”
Powertrain engineers everywhere are focused on vehicle performance, fuel economy, and emission requirements, but approaches vary with geography, according to Kevin Klein, automotive microcontroller marketing manager at Freescale Semiconductor.
“Attention is focused on hybrids in North America, where emission requirements involve a dramatic increase that affects powertrain and steering,” Klein said. “Hybrid control systems are complex, requiring sophisticated control of electric motors, battery management, and power conversion. There are pretty intense bandwidth communication issues among modules for drivability and feel, and FlexRay is a means of handling that.”
Klein observed that engineers in Europe are placing less emphasis on hybrids than on common rail direct-injection diesel engine for fuel economy. “Over half the cars in Europe are diesels, and diesel fuel is subsidized,” he noted.
“In India, Asia, and Latin America, the focus is on improving emissions. Design engineers have a clean slate for developing all new systems, and they are doing a quick catch-up, leapfrogging about 15 years of technology; doing the same things as in Europe and North America, but at lower cost points.”
Freescale Semiconductor offers its MPC5500 MCU family for engine and transmission control applications. Based on the e200 Power Architecture core and built on 130 nm technology, the MPC5500 family includes the MPC5534/33, with variable-length encoding (VLE) for improved code density; the MPC5553, with Fast Ethernet for engine control and other real-time management applications; the MPC5565, with 2 MB of flash, VLE, and floating-point capabilities for midrange powertrain applications, and the MPC5566, with 3MB of flash for memory-intensive powertrain applications.
Freescale is providing 32-bit Power Architecture MCUs for the hybrid drive train used in the Chevy Tahoe Hybrid and GMC Yukon Hybrid, GM's full-size hybrid SUVs. The vehicles use the two-mode hybrid system developed by GM, Chrysler, Mercedes, and BMW Group. In the first mode, at low speed and light loads, the vehicle can operate with electric power only, engine power only, or a combination of engine and electric power. The second mode, used primarily at highway speeds, provides full eight-cylinder engine power for passing other vehicles, pulling a trailer or climbing a steep grade.
The two-mode hybrid transmission is said to boost the fuel economy of the SUVs and large luxury vehicles by up to 50% in city driving compared to traditional gasoline engines. Powertrain control units based on Freescale MCUs monitor driving conditions and select the proper transmission mode automatically.
Freescale and STMicroelectronics have produced silicon for four 90 nm automotive Power Architecture microcontroller products resulting from the companies' joint design program, initiated two years ago. Target applications for the MCUs include powertrain.
Roger Forchammer, technical marketing manager for 16- and 32-bit MCUs at STMicro, explained that the collaboration with Freescale gives ST a leg up in powertrain applications, especially in North America, and also creates opportunities for Freescale, especially in Europe. Forchammer said the trend in North America is toward larger engines, while in Europe and Asia, designers opt for turbocharging four-cylinder vehicles.
“The market is very much in flux,” Forchammer said, “but we're seeing (semiconductor) sockets in all directions.” ST and Freescale are currently sampling a 32-bit Power PC MCU called Monaco that targets four-cylinder engines. It's based on an 80 MHz, e200Z3 core and comes with either 1 MB or 1.5 MB of flash memory. The part also features an engine control timer peripheral that offloads time- and angle-related calculations from the main processor. Forchammer said ST and Freescale intend to stress the reusability of code when marketing the Monaco and other processors based on the firms' collaboration.
Renesas Technology America touts the large memory capacity of its 32-bit SH72546RFCC microcontroller, which targets real-time engine and transmission control applications. Built with a 90 nm process node, the device achieves an operating speed of 200 MHz, can withstand temperatures up to 125 °C, and features up to 3.75 MB of on-chip flash plus 128 KB of on-chip flash with functions virtually equivalent to those of EEPROM. Amrit Vivekanand, marketing manager for Renesas' automotive business unit, said the chip's memory is sufficient for storing high-precision, real-time control algorithms.
The SH-2A CPU core of the SH72546RFCC is an enhanced superscalar design with a built-in double precision floating-point unit said to deliver about four times the performance of the 80 MHz Renesas SH-2E (SH-2 and single-precision FPU) core currently used in powertrain systems. A cache unit allows single-cycle access to the on-chip flash memory at 200 MHz for application processing.
The SH72546RFCC is a preproduction device optimized for control program development. It offers features tailored for software design and debugging, and forms the basis for a mass-production product family. The company promises that engineers who develop systems using the SH72546RFCC will be able to make a seamless transition to lower-cost mass-production devices.
Powertrain engineering provides ample opportunities for innovation. Continental is supplying the power electronics module that controls the flow of energy between the engine and the energy accumulator on BMW's X5-based Vision EfficientDynamics concept vehicle. Continental said the compact module is flange-mounted on the vehicle's transmission housing and added that engineers are working on an even smaller module — one that will fit in the space otherwise occupied by the alternator. Its design allows components to be used for different power categories and various installation circumstances.
Hella KGaA Hueck & Co. develops microcontroller-based throttle control actuators and fuel pump modules, and has designed an integrated chassis control module with diagnostic capabilities for a major U.S. automaker. Product marketing manager Roland Franz said Hella's products help reduce fuel consumption, lighten the electrical load within the vehicle, and eliminate components and associates costs.
BorgWarner subsidiary BERU AG has developed glow plugs that heat up in less than a second to help diesel engines start faster and more safely. Eduardo Vultorius, vice president and general manager of Beru's North American operations, said new glow plug control modules can maintain temperature more accurately and reduce cold start power requirements by two thirds. They also last longer than earlier models.
The complexity of current-generation powertrain designs demands the best available design and simulation tools. In the latest version of WAVE, its engine performance and gas dynamics simulation software, Ricardo improved the user interface and upgraded 3D functions.
“In the past, developers would put subsystems together and then go and test them on the road,” said Kregg Wiggins, vice president of Continental Automotive's Powertrain Division in North America. “Now most OEMs have migrated to lab-based and math-based modeling.” Standards like AUTOSAR are also gaining traction in the powertrain domain, Wiggins added.
Visteon used FlexRay architecture for the steer-by-wire system on the GM Sequel. Peter Lloyd, Visteon's director of powertrain electronics, said the system consists of front and rear electromechanical actuators, a torque feedback emulator for the steering wheel, and a distributed electronic control system. Redundant sensors, actuators, controllers and power provide a back-up structure that allows the system to be fault-tolerant. Control is provided by multiple electronic control units that are linked by FlexRay. “The system on the Sequel uses a steering wheel — a mechanism all drivers know — rather than a joystick,” Lloyd noted.
“Automakers are adopting advanced mathematical techniques in their engine development process so they can meet the time and cost deadlines due to aggressive standards,” said Jon Friedman, automotive industry marketing manager at The MathWorks.
“Model-based design has been heavily adopted in powertrain because the problem is so complicated and the return on investment in tools and training are easier to understand,” Friedman added. “Model-based design and analytical tools are especially critical in hybrids because the technology is moving so fast, and getting it wrong is so costly.”
Friedman said automakers have made big strides in algorithm developmen — including automatic code generation — and verification, through software in the loop and processor in the loop. “The goal is to find problems where and when they are cheapest to fix. This is especially critical in hybrid design, where hardware and algorithms come together at the same time.”
Friedman noted that the automotive industry is shifting away from the traditional process of tuning last year's prototype toward an analytical process, and the competitive advantage is not just in using analytical tools, but how much and how deeply they're used.”
“Multiple domains are being integrated,” concurred Lee Johnson, senior applications engineering manager for the Saber analysis system at Synopsys. “The next step is to account for more detailed effects through more complex models-without so many prototype iterations; to support robust design and similar techniques.”
|Continental Automotive Systems||www.conti-online.com|
|Hella KGaA Hueck & Co.||www.hella.com|
|Renesas Technology America||www.renesas.com|
John Day writes regularly about automotive electronics and other technology topics. He holds a BA degree in liberal arts from Northeastern University and an MA in journalism from Penn State. He is based in Michigan and can be reached by e-mail at