The move to hybrid powertrains adds a new level of complexity to powertrain development, forcing engineers to control the electric components and mesh them seamlessly with an internal-combustion engine. ICE and electric systems are now managed by dedicated controllers, and there’s little plan to integrate them in the near term.
Integration is an important cost-cutting tool for electronics engineers, who can often leverage microcontroller advances to manage more functions with a powerful chip, eliminating a microcontroller or even an entire module. But in this nascent phase of electrification, few engineers are looking at ways to use, say, an engine controller to manage some aspects of the electric system.
Dedicated controls may cost more, but they give developers a lot of freedom. That’s important today, when electric drive systems are being added to different vehicles. Most automakers want to leverage an electric powertrain system in more than one vehicle so they can recoup the high development costs more quickly.
“We’re still pushing engine technology that’s independent of hybrid technology; we want to be able to mix and match,” said Mike Grimes, General Motors’ Technical Fellow for control system architecture. “We keep the architectures separate so we can match any hybrid to any engine.”
On the electric-system side, engineers are still using far more custom devices than in conventional ICE controls systems. Developers usually try to replace custom chips with standard components, but that’s difficult in applications such as electric powertrains, where requirements are still evolving and solutions are improving more rapidly than in mature fuel-based systems. Custom chips are often better suited to new challenges such as managing huge battery packs.
“ASICs are still key parts for battery management,” said Gary Cameron, the director of Forward and Advanced Power Electronics Engineering at Delphi Automotive.
Most engineers feel that there will eventually be a drive to combine ICE and electric controls, though it’s too early to suggest much of a timeframe for this sort of up integration. However, some are already thinking about which functions will be the easiest to combine.
“In an effort to control costs, transmission controls will be up integrated into the hybrid controller as volumes increase,” said Carl Bonfiglio, Senior Marketing Manager, Powertrain & Electric at Infineon Technologies North America.