Delphi Automotive Systems has teamed with Orbital Engine Corp. to develop a combination spark plug/air-assist type fuel injector that will fit virtually any current size spark plug hole.

By eliminating the need to have separate access to the combustion chamber for direct fuel injection (DI), it is expected this will speed the introduction of DI technology.

Orbital CEO Kim Schlunke says, “The spark plug injector developed by Orbital will now be refined for commercial application by Delphi … it is an extension of our core fuel-injection joint venture with Siemens Automotive.”

A spokesperson for Delphi says that the spark plug/injector can be threaded for screw-in applications, like a spark plug, or can be installed through straight holes, whichever the customer prefers.

The unit illustrated by the accompanying drawing is understood to be a configuration suitable for research purposes and perhaps for some types of engines where there is space available. Delphi says it will respond to whatever needs its customers have for sizes and shapes to satisfy packaging requirements.

Aside from the implications of such a system — to simplify conversion of production engines with manifold port injection to DI (in-cylinder) fuel injection — the near-term availability of such units could speed up combustion research and field trials using current engines, whether the 2-, 3-, 4- or 5-valves per cylinder type. Premium engines with two spark plugs per cylinder might offer an opportunity to develop useful information regarding two DI points per cylinder.

A highly placed General Motors Corp. source tells WEVTU that GM already is testing engines equipped with the spark plug/injector unit.