Auto Manufacturers' Drive to Simplify

Forconsumers, hybrid powertrains mean better gas mileage. For electricalengineers, they mean more controllers, more connectors and more wires.

And moreheadaches.

"A hybridhas an inverter and the inverter needs a controller," says Robert Schumacher,general director for advanced products and business development at DelphiElectronics & Safety. "It also needs a supervisory controller to tell theinverter and the engine what to do. And it needs a controller for the dc/dcconverter and another one for monitoring the battery. Each of these(controllers) has a box and a big connector and a power harness and a signalharness. That's the way you do electrification today."

Forautomotive engineers, the challenge lies in the fact that most hybrids arebeing built atop existing vehicle platforms. That, in turn, means that all ofthose new components must be layered atop pre-existing electrical architectures.

Still,we've yet to mention the really challenging part of this electrical designtask: Many vehicles, it seems, were already reaching their limits in terms ofmicrocontrollers (MCUs) and wiring before hybrids began to proliferate. Foryears, vehicleshave used microcontrollers as the brains for virtually every major systemincluding engine, transmission, air bags, instrument clusters, radio, brakingand stability control. And that'sjust the beginning. In addition to those systems, which generally use 32-bitMCUs, today's vehicles are also employing 8-bit processors to control the powersteering, ignition, horn, headlights, seat motors, turn signals, dome lights,DVD players, window lifts, heating, cooling, compressors, pumps and tirepressure management systems, to namejust a few.

The resultis a wiring nightmare for automakers. Vehicle engineers now must contend with35 to 40 electronic control units (ECUs) on an average vehicle and up to 80 inluxury cars. Moreover, the typical mid-size contains between 45 and 70 lb ofwiring. And the numbers are expected torise as vehicles migrate toward hybrid propulsion systems.

Forengineers, the problems with all this complexity are twofold: cost andpotential failures. "We're rightup against the limit right now," says Chris Thibodeau, director of globaltechnology for electrical/electronic products at General Motors Corp. "We need tofind unique ways to integrate features and functions, and still give ourcustomers what they want without overloading our controllers."

Electronic Solutions

Tier-oneelectronics suppliers and semiconductor makers are trying to help automakers, but solving the problem isn't easy. Electronics technology ismoving so fast that it's difficult for OEM engineers to keep up with it. As aresult, automakers and suppliers need tighter cooperation than ever.

"Carmakersare more involved in terms of what they want from an electronicsstandpoint today," says Amrit Vivekanand, director of business development for Renesas Electronics America, asemiconductor supplier to the auto industry."With infotainment and safety systems, they're dealing with model yearsthat are further out, so they're looking for electronic products that haven'teven been made yet. For us, it's a matter of modifying product development thathasn't happened yet."

Semiconductor suppliers are encouraging automakers toconsolidate. In many cases, they're tellingthem to employ fewer microcontrollers. In their place, they'resuggesting more dual-core MCUs and more Flash memory. Those products, they say, could enable a vehicle'selectrical architecture to handle applications that have reached two or threemegabytes in program size.

"If you go back 10 years, 32K and 64K of Flash on the chip wasenough," Vivekanand says."Today, even an 8-bit micro needs 256K of Flash. Thirty-two bit processors needone, two and even three megabytes of Flash."

Automakers and tier-onesuppliers haven't moved toward dual-cores in a big way yet, but semiconductormakers say that time is coming. "Oftentimes, events in a vehicle require quickresponses, and you want to be able to handle more than one of those events at atime," Vivekanand says. "Youdon't want your micro to be off doing something else when a critical eventcomes in."

Consolidating Domains

The reason for moving to dual-cores and higher Flashsizes is simple: Automakers need better and faster devices that will enablethem to consolidate more functions into fewer electronic modules.

In today's architectures, modules are located all over thevehicle. Engine controls, for example, are tucked under the hood. Transmissioncontrols are on the transmission, cockpit controls are mounted on the firewalland safety modules tend to be located near sensors.

But automakers want to be able to consolidate modules, either bygeographic zones in the vehicle or by domains. Delphi, for example, hasdeveloped a Linux-based computing platform to consolidate the computing for acolor reconfigurable cluster, center console display, voice recognition system,and telematics system that uses Wi-Fi to connect to an Android-based smartphoneset-up. The company says itsLinux-based platform also offers the headroom to allow for incorporation ofactive safety systems, such as collision warning.

For hybrid vehicles, Delphi has also developed a product calledthe PowerBox. A self-containedhybrid propulsion system, the Power Box fits behind a vehicle's rear seat,incorporating a hybrid control unit motor controller and battery managementcontroller, along with a 120V lithium-ion battery pack, traction inverter anddc/dc converter. Shanghai Automotive Industry Corp. (SAIC) in China recentlyused the Power Box to convert a four-door, medium-sized, gasoline-burningvehicle into a hybrid.

Schemes such as the Power Box are more appealing to automakersbecause they can bunch control systems as part of a domain, rather than as partof a geographic zone. Using such strategies, suppliers say they seeopportunities for automakers to eliminate multiple processors around thevehicle. Microprocessors for motors and pumps, for example, can easily begrouped together.

"In many cases today, you've gotone micro per pump," Vivekanand says."But you can integrate those functions into one module and have one powerful micro controlling five pumps. It's not an issue to do that."

For automakers - who typicallyscrape to save pennies per vehicle - the bottom line is cost. "It can be adollar or two," says Thibodeau. "But we've seen studies that show it can be upto $10 per car."

Simulating the Changes

Integrating and testing those resulting systems, however,is no simple task.

"One of the big problems for OEMs is how do they make sure allthese modules from different tier-one suppliers will play together nicely?"Vivekanand asks. "It's a real challenge. It can push the vehicle launchesfarther out and cause a lot of finger-pointing."

Tier-one electronics suppliers, such as Delphi and Visteon, are helping by providing software models that showhow a proposed electronics architecture might work. In a door module, forexample, a software model might simulate the operation of a window lift motor,a door lamp and a door lock, thus allowing engineers to see if there are anyconflicts between them.

One such product, Delphi's eScout, allows engineers to simulatethe operation of a vehicle's entire electrical architecture. Delphi employedeScout in the design of an electrical architecture for an unnamed automaker,reducing its microcontroller count from 40 to 10, while cutting electronicscost by 35 percent and reducing the number of modules, connectors, power supplies and wires.

"It shows you where the computing centers are and identifies allthe signal wires and power wires that run between the boxes," Schumacher says."It tells you the number of wires and the number of pins on the connectors. Iteven keeps track of all the signals for the features and functions, and tellsyou what the high-level architecture looks like."

Automakers are also employing modeling software from companiessuch as The MathWorks. During the development of the Chevy Volt, GM engineeringteams employed model-based design and simulation in the prototyping of thepropulsion and battery management systems, even as the technology was barelyemerging from the research stage.

"We progressed on the Volt's development without having thebattery technology in place yet," says Karla J. Wallace, senior manager forelectronics engineering, integration and software at GM. Wallace says that GM startedmodeling with Simulink, then graduated to Real-Time Workshop Embedded Coder tocreate the C code that went into the Volt's electronic control system.

For automakers, however, an equally important set of solutionslies in common efforts shared by the entire industry. Autosar(Automotive Open System Architecture), an industry standards group, helps carmanufacturers by providing standardized hardware and software interfaces forexterior lighting, mirrors, seats, anti-theft systems, defrost controls, remotekeyless entry, parking distance control and numerous other electronic features.Members of the organization include BMW, Bosch, Continental, Daimler, Ford, GM,PSA Peugeot Citroen, Toyota, Volkswagen and dozens of suppliers.

"When you have an industrystandard such as Autosar, you can learn from others in the industry," ?Thibodeau explains. "Having standard hardware and softwareinterfaces across all the controllers allows us to partition our systems moreeffectively."

The Road to 'Up-Integration'

For automakers, the road to electrical simplicity isexpected to be a bumpy one. The reason: It's easier for them to simplify avehicle's architecture while designing from scratch. Laying new features atopold ones, they say, makes integration extremely difficult.

"Features sometimes take us bysurprise," Thibodeau says. "We try to integrate them as fast as possible inorder to be competitive, but we may not always be able to do it in the bestpossible way. We usually look to improve itin the next go-round."

The goal, however, remains. Automotive engineers know that"up-integration" is inevitable and efforts to improve electrical architectureswill continue for a long time, especially as new vehicle platforms areintroduced.

"If you ask automakers whattheir most difficult task is, they'll all say that it's wire-routing and makingconnections. ?We can all do better. The trick is doing it in an elegant andsophisticated way," Thibodeausays.