Fuel injector with internal heater

Abstract

A fuel injector has an internal heater energized during cold starting to reduce emissions, the heater being a ceramic hollow cylinder disposed within a valve body just upstream of a valve seat where fuel is injected through an orifice into the engine. Conductors for energizing the heater extend into the valve body and are sealed against the escape of pressurized fuel. In one version, the conductors extend through an O-ring to be sealed. In another version the conductors include pins extending through the valve body sidewall with glass seals fused to the valve body and the pins. The conductors may comprise flat foil strips clamped between the O-ring and an elastomeric washer. The conductors also may be molded into the magnetic coil bobbin and sealed where the conductors emerge into the fuel cavity. The heater has metallized surfaces to create current flow through its wall thickness, and the conductors are electrically connected respectively to the inner end and outer surfaces of the hollow cylinder by metallization patterns enabling both mechanical contacts on the outside of the heater.