Internal-combustion engines – Charge forming device – Heating of combustible mixture
Reexamination Certificate
1999-06-25
2001-01-23
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Charge forming device
Heating of combustible mixture
Reexamination Certificate
active
06176226
ABSTRACT:
BACKGROUND OF INVENTION
The invention relates in general to heated tip injectors and in particular to a method and apparatus for controlling heated tip injectors.
In general, a heated tip fuel injector comprises an electric heater in the fuel path within an injector valve body. Examples of heated tip fuel injectors are described in U.S. patent application Ser. No. 09/088,126 entitled “Method of Preheating Fuel with an Internal Heater” filed on Jun. 1, 1998; U.S. patent application Ser. No. 09/088,127 entitled “Fuel Injector with Internal Heater” filed on Jun. 1, 1998; U.S. provisional patent application serial No. 60/122,162 entitled “A Method of Using an Internally Heated Tip Injector to Reduce Hydrocarbon Emissions During Cold-Start” filed on Feb. 26, 1999; and U.S. Pat. No. 5,758,826. The aforementioned three U.S. patent applications and one U.S. patent are hereby expressly incorporated by reference.
U.S. patent application Ser. No. 09/088,126 describes an electronic circuit for driving a heated tip injector having a two-pin connector. The electronic circuit alternately drives the injector coil and heater. U.S. Pat. No. 5,758,826 discloses a heated tip injector having a connector with more than two pins, in particular, three pins. The present invention is a method and apparatus for controlling a heated tip injector having a connector with more than two pins.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method and apparatus for controlling a heated tip injector having a connector with more than two pins.
It is another object of the invention to provide a method and apparatus for controlling a heated tip injector wherein the voltage drop across the injector coil is minimized.
It is a further object of the invention to provide a method and apparatus for controlling a heated tip injector wherein the heater is switched in a time delayed or pulse-reversed manner to the injector coil pulses.
These and other objects of the invention are achieved in a first embodiment by a method of controlling heated tip injectors in an engine comprising (a) providing a plurality of heated tip injectors each having a coil and an internal heater; (b) maintaining all the internal heaters in an OFF state while the engine is cranking; (c) maintaining an internal heater in an OFF state if its respective coil is ON; and (d) maintaining an internal heater in an ON state if the engine is not cranking and the internal heater's respective coil is OFF. The first embodiment may also comprise (e) maintaining all the internal heaters in an OFF state after a predetermined time.
A first embodiment of an apparatus for controlling heated tip injectors in an engine comprises a plurality of heated tip injectors each having a coil and an internal heater; a power supply; an ignition switch connected to the power supply, one end of each coil and heater being connected together and to the ignition switch; an engine electronic control unit, another end of each coil being connected to the engine electronic control unit; means for switching each internal heater ON and OFF, another end of each internal heater being connected through a respective means for switching to ground; a crank circuit including a crank for cranking the engine; and means for isolating the crank circuit from the engine electronic control unit.
A second embodiment of a method of controlling heated tip injectors in an engine comprises (a) providing a plurality of heated tip injectors each having a coil and an internal heater; (b) maintaining all the internal heaters in an OFF state while the engine is cranking; (c) maintaining an internal heater in an OFF state if its respective coil is ON; (d) enabling a first internal heater after the engine stops cranking; (e) enabling remaining internal heaters sequentially with a time delay between enablement of each internal heater; and (f) maintaining an internal heater in an ON state if the engine is not cranking, the internal heater's respective coil is OFF and the internal heater has been enabled.
A second embodiment of an apparatus for controlling heated tip injectors in an engine comprises a plurality of heated tip injectors each having a coil and an internal heater; a power supply; an ignition switch connected to the power supply, one end of each coil and heater being connected together and to the ignition switch; an engine electronic control unit, another end of each coil being connected to the engine electronic control unit; means for switching each internal heater ON and OFF, another end of each internal heater being connected through a respective means for switching to ground; a crank for cranking the engine; and means for providing a time delay for sequentially enabling the internal heaters.
A third embodiment of a method of controlling heated tip injectors in an engine comprises (a) providing a plurality of heated tip injectors each having a coil and an internal heater; (b) maintaining all the internal heaters in an OFF state while the engine is cranking; (c) maintaining all the internal heaters in an OFF state if any coil is ON; and (d) maintaining an internal heater in an ON state if the engine is not cranking and no coil is ON.
A third embodiment of an apparatus for controlling heated tip injectors in an engine comprises a plurality of heated tip injectors each having a coil and an internal heater; a power supply; an ignition switch connected to the power supply, one end of each coil and heater being connected together and to the ignition switch; an engine electronic control unit, another end of each coil being connected to the engine electronic control unit; means for switching each internal heater ON and OFF, another end of each internal heater being connected through a respective means for switching to ground; a crank for cranking the engine; and means for maintaining all the internal heaters in an OFF state while the engine is cranking, maintaining all the internal heaters in an OFF state if any coil is ON and maintaining an internal heater in an ON state if the engine is not cranking and no coil is ON.
A fourth embodiment of a method of controlling heated tip injectors in an engine comprises (a) providing a plurality of heated tip injectors each having a coil and an internal heater; (b) maintaining all the internal heaters in an OFF state while the engine is cranking; (c) turning all internal heaters ON when current in any injector coil reaches a point at which its injector needle is completely open; and (d) turning all internal heaters OFF prior to any coil receiving a new coil pulse.
A fourth embodiment of an apparatus for controlling heated tip injectors in an engine comprises a plurality of heated tip injectors each having a coil and an internal heater; a power supply; an ignition switch connected to the power supply, one end of each coil and heater being connected together and to the ignition switch; an engine electronic control unit, another end of each coil being connected to the engine electronic control unit; means for switching each internal heater ON and OFF, another end of each internal heater being connected through a respective means for switching to ground and the electronic control unit; wherein the engine electronic control unit is programmed such that all the internal heaters are in an OFF state while the engine is cranking, all internal heaters are ON when current in any injector coil reaches a point at which its injector needle is completely open and all internal heaters are OFF prior to any coil receiving a new coil pulse.
A fifth embodiment of a method of controlling heated tip injectors in an engine comprises (a) providing a plurality of heated tip injectors each having a coil and an internal heater; and (b) turning the internal heaters ON at any time an ignition switch of the engine is closed, irrespective of a state of the coils.
A fifth embodiment of an apparatus for controlling heated tip injectors in an engine comprises a plurality of heated tip injectors each having a coil and an internal heater; a first power supply connected to t
Nines Jerry Edward
Wright Danny Orlen
Zimmerman Frank
McMahon Marguerite
Siemens Automotive Corporation
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