Diagnosis method for solenoid valve based on noise detection

• US 20070114481A1
• Filed: 11/17/2006
• Published: 05/24/2007
• Est. Priority Date: 11/18/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Suyama, Hironobu
• Granted Patent: US 7,877,194 B2
• Time in Patent Office: Days
• US Class Current: 251/129.150
• 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

According to the present invention, there is provided a diagnosis method for a solenoid valve which includes: energizing and deenergizing cyclically 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 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.

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:

energizing and deenergizing cyclically 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.

2. The diagnosis method as set forth in claim 1, wherein the solenoid valve is diagnosed as being in normal condition when each cycle of the energizing and deenergizing causes two of the noises.

3. The diagnosis method as set forth in claim 1, wherein the solenoid valve is diagnosed as being in semi-locked condition when each cycle of the energizing and deenergizing causes only one of the noises.

4. The diagnosis method as set forth in claim 1, further comprising diagnosing, when there is no noise caused by the energizing and deenergizing, the solenoid valve as being in fully-locked condition.

5. The diagnosis method as set forth in claim 1, further comprising energizing, when the solenoid valve is diagnosed as being in abnormal condition, the solenoid of the solenoid valve with electric power stronger than that for normally energizing the solenoid to recover the solenoid valve to normal.

6. 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.

7. The diagnosis method as set forth in claim 6, further comprising, before the energizing and deenergizing, selecting one of the plurality of solenoid valves in the fuel supply unit as a target valve to be exclusively diagnosed.

8. The diagnosis method as set forth in claim 7, wherein the target valve is to be exclusively diagnosed when the engine is stopped.

9. The diagnosis method as set forth in claim 6, 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.

10. The diagnosis method as set forth in claim 9, wherein the solenoid valves are alternately activated according to suction strokes of the respectively corresponding pumps.

11. 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.