consumers, hybrid powertrains mean better gas mileage. For electrical
engineers, they mean more controllers, more connectors and more wires.
has an inverter and the inverter needs a controller," says Robert Schumacher,
general director for advanced products and business development at Delphi
Electronics & Safety. "It also needs a supervisory controller to tell the
inverter and the engine what to do. And it needs a controller for the dc/dc
converter and another one for monitoring the battery. Each of these
(controllers) has a box and a big connector and a power harness and a signal
harness. That's the way you do electrification today."
automotive engineers, the challenge lies in the fact that most hybrids are
being built atop existing vehicle platforms. That, in turn, means that all of
those new components must be layered atop pre-existing electrical architectures.
we've yet to mention the really challenging part of this electrical design
task: Many vehicles, it seems, were already reaching their limits in terms of
microcontrollers (MCUs) and wiring before hybrids began to proliferate. For
have used microcontrollers as the brains for virtually every major system
including engine, transmission, air bags, instrument clusters, radio, braking
and stability control. And that's
just the beginning. In addition to those systems, which generally use 32-bit
MCUs, today's vehicles are also employing 8-bit processors to control the power
steering, ignition, horn, headlights, seat motors, turn signals, dome lights,
DVD players, window lifts, heating, cooling, compressors, pumps and tire
pressure management systems, to name
just a few.
is a wiring nightmare for automakers. Vehicle engineers now must contend with
35 to 40 electronic control units (ECUs) on an average vehicle and up to 80 in
luxury cars. Moreover, the typical mid-size contains between 45 and 70 lb of
wiring. And the numbers are expected to
rise as vehicles migrate toward hybrid propulsion systems.
engineers, the problems with all this complexity are twofold: cost and
potential failures. "We're right
up against the limit right now," says Chris Thibodeau, director of global
technology for electrical/electronic products at General Motors Corp. "We need to
find unique ways to integrate features and functions, and still give our
customers what they want without overloading our controllers."
electronics suppliers and semiconductor makers are trying to help automakers, but solving the problem isn't easy. Electronics technology is
moving so fast that it's difficult for OEM engineers to keep up with it. As a
result, automakers and suppliers need tighter cooperation than ever.
Click here for larger image.
are more involved in terms of what they want from an electronics
standpoint today," says Amrit Vivekanand, director of business development for
Renesas Electronics America
semiconductor supplier to the auto industry.
"With infotainment and safety systems, they're dealing with model years
that are further out, so they're looking for electronic products that haven't
even been made yet. For us, it's a matter of modifying product development that
hasn't happened yet."
Semiconductor suppliers are encouraging automakers to
consolidate. In many cases, they're telling
them to employ fewer microcontrollers. In their place, they're
suggesting more dual-core MCUs and more Flash memory. Those products, they say, could enable a vehicle's
electrical architecture to handle applications that have reached two or three
megabytes in program size.
"If you go back 10 years, 32K and 64K of Flash on the chip was
enough," Vivekanand says.
"Today, even an 8-bit micro needs 256K of Flash. Thirty-two bit processors need
one, two and even three megabytes of Flash."
Automakers and tier-one
suppliers haven't moved toward dual-cores in a big way yet, but semiconductor
makers say that time is coming. "Oftentimes, events in a vehicle require quick
responses, and you want to be able to handle more than one of those events at a
time," Vivekanand says. "You
don't want your micro to be off doing something else when a critical event
The reason for moving to dual-cores and higher Flash
sizes is simple: Automakers need better and faster devices that will enable
them to consolidate more functions into fewer electronic modules.
In today's architectures, modules are located all over the
vehicle. Engine controls, for example, are tucked under the hood. Transmission
controls are on the transmission, cockpit controls are mounted on the firewall
and safety modules tend to be located near sensors.
But automakers want to be able to consolidate modules, either by
geographic zones in the vehicle or by domains. Delphi, for example, has
developed a Linux-based computing platform to consolidate the computing for a
color reconfigurable cluster, center console display, voice recognition system,
and telematics system that uses Wi-Fi to connect to an Android-based smartphone
set-up. The company says its
Linux-based platform also offers the headroom to allow for incorporation of
active safety systems, such as collision warning.
For hybrid vehicles, Delphi has also developed a product called
. A self-contained
hybrid propulsion system, the Power Box fits behind a vehicle's rear seat,
incorporating a hybrid control unit motor controller and battery management
controller, along with a 120V lithium-ion battery pack, traction inverter and
dc/dc converter. Shanghai Automotive Industry Corp. (SAIC) in China recently
used the Power Box to convert a four-door, medium-sized, gasoline-burning
vehicle into a hybrid.
Schemes such as the Power Box are more appealing to automakers
because they can bunch control systems as part of a domain, rather than as part
of a geographic zone. Using such strategies, suppliers say they see
opportunities for automakers to eliminate multiple processors around the
vehicle. Microprocessors for motors and pumps, for example, can easily be
"In many cases today, you've got
one 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 typically
scrape to save pennies per vehicle - the bottom line is cost. "It can be a
dollar or two," says Thibodeau. "But we've seen studies that show it can be up
to $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 all
these modules from different tier-one suppliers will play together nicely?"
Vivekanand asks. "It's a real challenge. It can push the vehicle launches
farther out and cause a lot of finger-pointing."
Tier-one electronics suppliers, such as Delphi and Visteon, are helping by providing software models that show
how a proposed electronics architecture might work. In a door module, for
example, 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 any
conflicts between them.
One such product, Delphi's eScout, allows engineers to simulate
the operation of a vehicle's entire electrical architecture. Delphi employed
eScout in the design of an electrical architecture for an unnamed automaker,
reducing its microcontroller count from 40 to 10, while cutting electronics
cost by 35 percent and reducing the number of modules, connectors, power supplies and wires.
"It shows you where the computing centers are and identifies all
the 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. It
even keeps track of all the signals for the features and functions, and tells
you what the high-level architecture looks like."
Automakers are also employing modeling software from companies
such as The MathWorks. During the development of the Chevy Volt, GM engineering
teams employed model-based design and simulation in the prototyping of the
propulsion and battery management systems, even as the technology was barely
emerging from the research stage.
"We progressed on the Volt's development without having the
battery technology in place yet," says Karla J. Wallace, senior manager for
electronics engineering, integration and software at GM. Wallace says that GM started
modeling with Simulink, then graduated to Real-Time Workshop Embedded Coder to
create the C code that went into the Volt's electronic control system.
For automakers, however, an equally important set of solutions
lies in common efforts shared by the entire industry. Autosar
(Automotive Open System Architecture), an industry standards group, helps car
manufacturers by providing standardized hardware and software interfaces for
exterior lighting, mirrors, seats, anti-theft systems, defrost controls, remote
keyless 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 industry
standard such as Autosar, you can learn from others in the industry," ?Thibodeau explains. "Having standard hardware and software
interfaces across all the controllers allows us to partition our systems more
The Road to ‘Up-Integration'
For automakers, the road to electrical simplicity is
expected to be a bumpy one. The reason: It's easier for them to simplify a
vehicle's architecture while designing from scratch. Laying new features atop
old ones, they say, makes integration extremely difficult.
"Features sometimes take us by
surprise," Thibodeau says. "We try to integrate them as fast as possible in
order to be competitive, but we may not always be able to do it in the best
possible way. We usually look to improve it
in the next go-round."
The goal, however, remains. Automotive engineers know that
"up-integration" is inevitable and efforts to improve electrical architectures
will continue for a long time, especially as new vehicle platforms are
"If you ask automakers what
their most difficult task is, they'll all say that it's wire-routing and making
connections. ?We can all do better. The trick is doing it in an elegant and
sophisticated way," Thibodeau