Use of Highly Integrated Components in the Design of Small Gasoline Engine Controllers 2012-32-0046

As small gasoline engines evolve similar to their larger automotive cousins to use more sophisticated electronic engine controls, new challenges will face the small engine manufacturers. Constraints in size and cost as well as having to meet new emission and fuel efficiency standards, driven by recent legislation, will hasten the progression from magneto and CDI (Capacitive Discharge Ignition) to TCI (Transistor Controlled Ignition), EFI (Electronic Fuel Injection) and ultimately, DFI (Direct Fuel Injection). The rapid miniaturization of electronic components, as a side benefit of the new smart phone and tablet market explosion, will help the manufacturers meet these challenges but new system and circuit topologies will also be required. This paper will discuss one of these new topologies, the Multiple Chip Module (MCM), and how the integration of analog circuits and microcomputers into a single SiP (System in Package) MCM can be a benefit. Included in the paper are the advantages and disadvantages of the SiP MCM methodology as it was implemented in a small engine laboratory and as was adopted by a major small engine manufacturer. Both the vehicle and the power tool small engine market segments will be reviewed in this paper to show how this new topology can be a benefit to both.

Some conclusions provided by this paper will include:

1. 1)
   For small gasoline engine control additional functionality and performance enhancements can be obtained through the use of software algorithms and calibration tables that are not possible with older mechanical fixed timing architectures.
2. 2)
   The Multiple Chip Module (MCM) approach reduces the size and cost of engine controllers while increasing the reliability over discrete component solutions.
3. 3)
   One single micro-programmable MCM can replace dozens of discrete components and increase design reusability.

To demonstrate these conclusions, two reference design engine control units were produced, one using discrete components, and the other, using the new SiP MCM architecture. A comparison of both approaches is provided.