Integration Key When Managing ECU Proliferation
By Derek Stark WardsAuto.com, Oct 21, 2008 5:51 PM

DETROIT – Today’s vehicles rely on increasingly sophisticated electronics, but auto makers say the number of electronic control units will level off and then drop in the next few years.

Gunter Reichert, vice president-driver assistance for BMW AG’s body electrical/electronics and electronic networks group, says at the Convergence Transportation Electronics Conference here the German auto maker has up to 70 ECUs in its most expensive vehicles and between 40 and 50 in other models.

The question of ECU proliferation came up during Tuesday’s “Car Makers Speak” panel, hosted by electronics expert Paul Hansen.

While 70 is approximately the maximum number of ECUs a vehicle can accommodate, Reichert says “BMW is working hard to reduce the number of ECUs.”

In powertrain applications, ECUs govern, among other things, fuel-injection systems, ignition timing, idle-speed control and the fuel pump, as well as gear-shifting.

ECUs also are becoming integral to steering, braking, safety, comfort and convenience systems.

Due to the increasing complexity of electrical-distribution systems, as well as stringent quality and cost requirements, OEMs are calling for fewer ECUs in order to streamline the design process.

Chrysler’s Andreas Schell

Chrysler LLC has between 25 and 35 ECUs per vehicle, on average, says Andreas Schell, vice president-electrical/electronics for Chrysler’s engineering core group.

“That average will increase,” he says. “A few more will be added in the next few years, but that number will stabilize. And then we’ll bring that number down.”

A General Motor Corp. executive also says he expects his company to use fewer ECUs in the future.

“We have between 30 and 40 modules now,” says Chris Thibodeau, director-global technology engineering for GM’s electrical/electronics products group. “The number of controllers we use will decrease over time.”

Likewise, at Ford Motor Co., the number of ECUs will “continue to drop as they become more powerful through integration,” says Jim Buczkowski, director-electrical and electronics systems for Ford’s Engineering Implementation organization.

Hansen asks the panelists to estimate each auto maker’s percentage of vehicle content that comes from electrical and electronic parts and software, and whether that percentage will increase or stay the same in the future.

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Tony Nakajima, senior chief engineer-Honda R&D Co. Ltd., quantifies that content for Honda-brand vehicles as between 20% and 50%. He says 50% represents the content for a hybrid-electric vehicle.

Chrysler’s Schell pegs electrical and electronic content on Chrysler vehicles at between 25% and 50%. “Expectations for electronics have significantly increased,” he says.

Thibodeau says GM averages “between 30% and 40%, but some of our vehicles are around 20%. For hybrids, there’s a lot more content. The work is in the software domain, and that’s where we are starting to focus.”

BMW averages 35% to 40%. “And in the future, we’ll have a slow increase up to 50%, but not through additional hardware,” Reichart says.

dstark@wardsauto.com