Diagnosis method for solenoid valve based on noise detection

• US 7,877,194 B2
• Filed: 11/17/2006
• Issued: 01/25/2011
• Est. Priority Date: 11/18/2005
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Suyama, Hironobu
• Primary Examiner(s): Cronin, Stephen K
• Assistant Examiner(s): VILAKAZI, SIZO BINDA
• Application Number:
  US11/600,842
• Publication Number:
  US 20070114481A1
• Time in Patent Office: 1,530 Days
• Field of Search: 123/299, 123/295, 123/301, 123/90.11, 123/490, 123/568.16, 701/111, 701/114, 73/351.1, 731/143.8, 731/145.8, 731/147.4, 702/183, 702/185
• US Class Current: 701/114
• CPC Class Codes: F02D 2041/2058 using information of the actual current value
• CPC Class Codes: F02D 2041/2089 detecting open circuits
• CPC Class Codes: F02D 2200/025 Engine noise, e.g. determined by using an acoustic sensor
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: F02D 41/3845 by controlling the flow into the common rail, e.g. the amount of fuel pumped
• CPC Class Codes: F02M 37/043 Arrangements for driving reciprocating piston-type pumps
• CPC Class Codes: F02M 37/06 mechanically driven
• CPC Class Codes: F16K 31/06 using a magnet , e.g. diaphragm valves, cutting off by means of a liquid
• CPC Class Codes: F16K 37/0091 by measuring fluid parameters

Abstract

A solenoid valve includes cyclically energizing and deenergizing a solenoid of the solenoid valve to repeatedly fully open and fully close the solenoid valve. When the energizing and deenergizing causes collisions of a moving member of the solenoid valve against at least one of a first and a second seat formed in a housing of the solenoid valve, noises are thus generated by the collisions and occurrence intervals of the noises are detected. Whether the solenoid valve is in normal or abnormal condition is diagnosed based on the detected occurrence intervals of the noises.

Claims

1. A diagnosis method for a solenoid valve, wherein the solenoid valve includes a housing with a first and a second seat formed therein, a moving member configured to be moved in the housing, and a solenoid, and wherein the solenoid valve is configured to fully open with the moving member resting on the first seat when the solenoid is energized and fully close with the moving member resting on the second seat when the solenoid is deenergized, the diagnosis method comprising:

cyclically energizing and deenergizing the solenoid of the solenoid valve to repeatedly fully open and fully close the solenoid valve;

when the energizing and deenergizing causes collisions of the moving member against at least one of the first and second seats in the solenoid valve and noises are thus generated by the collisions, detecting occurrence intervals of the noises; and

diagnosing whether the solenoid valve is in normal or abnormal condition based on the detected occurrence intervals of the noises,

wherein the solenoid valve is diagnosed;

as being in normal condition when each cycle of the energizing and deenergizing causes two noises;

as being in semi-locked condition when each cycle of the energizing and deenergizing causes only one noise; and

as being in fully-locked condition when there is no noise caused by the energizing and deenergizing.

2. The diagnosis method as set forth in claim 1, further comprising:

when the solenoid valve is diagnosed as being in abnormal condition, energizing the solenoid of the solenoid valve with electric power stronger than that used for normally energizing the solenoid to thus attempt return of the solenoid valve to a normal condition.

3. The diagnosis method as set forth in claim 1,

wherein the diagnosis method is for diagnosing a plurality of solenoid valves that are included in a fuel supply unit of a common rail fuel injection system for a diesel engine to control an amount of pressurized fuel supplied from the fuel supply unit to a common rail of the system;

and

the diagnosis method further comprises, before the step of energizing and deenergizing, selecting one of the plurality of solenoid valves in the fuel supply unit as a target valve to be exclusively diagnosed; and

the target valve is diagnosed only when the engine is stopped.

4. The diagnosis method as set forth in claim 3, wherein the fuel supply unit includes a plurality of pumps working to pressurize fuel, and each of the solenoid valves is mounted to a corresponding one of the pumps to control an amount of fuel sucked into the corresponding pump.

5. The diagnosis method as set forth in claim 4, wherein the solenoid valves are alternately activated according to suction strokes of the respectively corresponding pumps.

6. The diagnosis method as set forth in claim 1, wherein the solenoid valve is a pressure reducing valve mounted to a common rail of a common rail fuel injection system for a diesel engine to regulate fuel pressure in the common rail.

12. The diagnosis method as set forth in claim 1, wherein the solenoid valve is included in a fuel supply unit of a common rail fuel injection system for a diesel engine to control an amount of pressurized fuel supplied from the fuel supply unit to a common rail of the system,

the engine is stopped during the steps of cyclically energizing and deenergizing, detecting and diagnosing, and

the step of diagnosing is performed by relying on the acoustic sense of a diagnostician.

13. The diagnosis method as set forth in claim 6, wherein the engine is stopped during the steps of cyclically energizing and deenergizing, detecting and diagnosing, and

the step of diagnosing is performed by relying on the acoustic sense of a diagnostician.

7. A method for diagnosing the condition of a solenoid-controlled valve which, in use, is electrically driven to control fluid flow therethrough, said valve having a moving member which can move between first and second seated positions corresponding to fully-open and fully-closed valve operating positions, said method comprising:

driving said solenoid-controlled valve with an isolated electrical drive signal of predetermined frequency between its fully-open and fully-closed positions;

detecting expected acoustic noise occurrences normally generated when said moving member is caused to engage its seated positions; and

diagnosing valve condition, as being (a) normal if the frequency of said acoustic noise occurrences is twice said predetermined frequency, (b) semi-locked if the frequency of said acoustic noise occurrences is equal to said predetermined frequency, and (c) locked if no acoustic noise occurrences are detected.

8. A method as in claim 7, wherein plural of said solenoid-controlled valves are present but only one is tested at any given time.

9. A method as in claim 7, wherein said solenoid-controlled valve is part of a pressurized fuel delivery system for a diesel engine, said valve being used to maintain a predetermined fuel pressure in a fuel injection system common rail supplying pressurized fuel for injection into each of plural diesel engine cylinders.

10. A method as in claim 9, wherein said diesel engine is not operating during the steps of driving, detecting and diagnosing.

11. A method as in claim 9, wherein plural of said solenoid-controlled valves are present and wherein said driving, detecting and diagnosing steps are automatically performed by a computer-implemented diagnostic system connected to drive only one solenoid-controlled valve at a time.