When to Integrate or Not to Integrate - A VVA System Decision 2003-01-0031
Virtually all production engines today have some level of electronic control. As features have been added over the years, some of these Electronic Control Units (ECU's) have grown significantly in complexity, size and cost. As Variable Valve Actuation (VVA) systems evolve from simple, mechanically operated systems such as cam phasers to full VVA systems, electronic systems will also need to evolve to control them. This evolutionary path forces many system-level questions to be considered. Some global questions that will need to be considered as the industry continue on this path, are:
“What is the optimal level of electronics integration?”
“At what point should a distributed engine control system be considered?”
There are several key points that need to be considered to properly make these decisions, many of which will be addressed in this paper. A process for how these decisions might be made for a given system will be discussed. This process will then be applied to an engine control scheme for an engine utilizing a VVA system.