Electricity: measuring and testing – Internal-combustion engine ignition system or device – Coil
Reexamination Certificate
1998-12-23
2001-10-23
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Internal-combustion engine ignition system or device
Coil
C324S546000, C361S154000
Reexamination Certificate
active
06307376
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control system and/or method for sensing faulty solenoids. In particular, the present invention relates to a control system and/or method for sensing faults in the solenoids of solenoid-controlled actuators for vehicular automated or semi-automated change gear transmission systems.
2. Description of the Prior Art
Change-gear mechanical transmissions are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 3,105,395; 3,335,616; 4,428,469; 4,754,665; 4,920,815; 4,944,197; 5,086,897; 5,370,013; and 5,390,561, the disclosures of which are incorporated herein by reference. Two-position and three-position, fluid-actuated, actuator piston assemblies and actuator systems associated therewith also are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,899,607; 4,928,544; 4,936,156; 5,054,591; 5,193,410; 5,263,379; 5,272,441; 5,329,826; 5,651,292; and 5,661,998, the disclosures of which are incorporated herein by reference.
Transmission systems of particular reference are disclosed in the following patent applications, the disclosures of which are incorporated herein by reference:
Ser. No. 09/178,346 filed Oct. 22, 1998 entitled “ROBUST CONTROL FOR THREE-POSITION TRANSMISSION SHIFT ACTUATOR ASSEMBLY”
Ser. No. 08/053,089 filed Apr. 1, 1998 entitled “RANGE SHIFT CONTROL”
Ser. No. 08/053,090 filed Apr. 1, 1998 entitled “ADAPTIVE NEUTRAL SENSING”
Ser. No. 08/053,091 filed Apr. 1, 1998 entitled “JAW CLUTCH ENGAGEMENT CONTROL FOR ASSISTED, MANUALLY SHIFTED, SPLITTER-TYPE TRANSMISSION SYSTEM”
Ser. No. 08/053,092 filed Apr. 1, 1998 entitled “ENGINE FUEL CONTROL FOR COMPLETING SHIFTS IN CONTROLLER-ASSISTED, MANUALLY SHIFTED TRANSMISSIONS”
Ser. No. 08/053,093 filed Apr. 1, 1998 entitled “ADAPTIVE UPSHIFT JAW CLUTCH ENGAGEMENT CONTROL”
Ser. No. 08/053,095 filed Apr. 1, 1998 entitled “DYNAMIC RANGE SHIFT ACTUATION”
Ser. No. 08/053,181 filed Apr. 1, 1998 entitled “ADAPTIVE SPLITTER ACTUATOR ENGAGEMENT FORCE CONTROL”
Ser. No. 08/902,603 filed Aug. 7, 1997 entitled “PARTIALLY AUTOMATED, LEVER-SHIFTED MECHANICAL TRANSMISSION SYSTEM”
Ser. No. 08/990,678 filed Dec. 15, 1997 entitled “ASSISTED LEVER-SHIFTED TRANSMISSION”
Controls for automated and semi-automated transmission systems, including fault detection systems and/or methods, are known in the prior art as may be seen by reference to U.S. Pat. Nos. 4,595,986; 4,702,127; 4,922,425; 4,888,577; 4,849,899; and 5,272,441, the disclosures of which are hereby incorporated by reference.
It is known that solenoid-related faults sometimes occur in the solenoid-controlled actuators used in vehicular transmission systems. If such a fault occurs, it is highly desirable to indicate such a condition to the operator of the vehicle, and to initiate some safe form of recovery logic and/or temporary mode of operation. These actions will notify the operator that correction action is required, and will minimize the possibility of the transmission suffering mechanical damage or behaving in an unintended manner.
In order to properly respond to a solenoid-related fault, a reliable fault detection system must be implemented. Although examples of fault detection systems can be found in the prior art, such systems typically are complicated, cannot detect a wide variety of solenoid-related faults, or cannot reliably be implemented in all transmission control configurations. One particular problem with the prior art fault detection systems is their inability to be reliably implemented in low side solenoid driver circuit configurations, such configurations being desirable in that they enable a less complicated and lower cost electronic control unit to be used in the transmission control.
SUMMARY OF THE INVENTION
The present invention provides an improved fault detection system and method which minimizes or overcomes the problems of the prior art.
The fault detection system of the present invention includes a solenoid driver circuit for energizing and de-energizing the solenoid, a current sense circuit for sensing the current in the solenoid, and a power supply switching circuit for selectively connecting and disconnecting a supply voltage from the solenoid driver circuit. Also included is a processing circuit that is connected to and controls the solenoid driver circuit, the current sense circuit, and the power supply switching circuit. The processing circuit implements fault detection logic wherein the processing circuit senses the current in the solenoid and, if the sensed current exceeds a predetermined current value for a predetermined time period, disconnects the supply voltage from the solenoid driver circuit and measures the rate of voltage decay in the solenoid driver circuit to determine if an open circuit fault or a short circuit fault exists.
Other objects and advantages of the present invention will become apparent from a reading of the following description of the preferred embodiment taken in connection with the attached drawings.
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Alexander Randy
Wadas David L.
Wang Yei Dei
Eaton Corporation
Gordon Howard D.
Kosinski Charles E.
Metjahic Safet
Nguyen Vincent Q.
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