Gas sensor units for engines

• US 7,168,423 B2
• Filed: 07/28/2005
• Issued: 01/30/2007
• Est. Priority Date: 10/20/2004
• Status: Expired due to Fees

• Current Assignee: Zama Japan Kabushiki Kaisha
• Original Assignee: Zama Japan Co., Ltd. (Stihl Holding AG & Company KG)
• Inventors: Nonaka, Takumi
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US11/191,085
• Publication Number:
  US 20060081227A1
• Time in Patent Office: 551 Days
• Field of Search: 123/703, 123/672
• US Class Current: 123/703
• CPC Class Codes: F01N 13/008 Mounting or arrangement of exhaust sensors in or on exhaust apparatus sensor arrangements for engine control F02D41/1439
• CPC Class Codes: F01N 13/1822 for fixing exhaust pipes or devices to vehicle body
• CPC Class Codes: G01N 27/16 caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas
• CPC Class Codes: G01N 33/0009 General constructional details of gas analysers, e.g. portable test equipment G01N1/22 takes precedence

Abstract

In a multipurpose engine with a reduced or limited displacement adapted for use in a portable work machine or the like, the engine includes a detecting element of a gas sensor for controlling an air-fuel ratio. Damage or degradation of the detecting element due to vibration from the engine is reduced or eliminated. To achieve this, a supporting device having a vibration-damping-function is provided for supporting the gas sensor or the gas sensor unit containing the gas sensor. The supporting device permits the gas sensor or the gas sensor unit to move by an amount equal to or less than a predetermined extent of movement of the engine, so that the transmission of vibration from the engine directly to the gas sensor is reduced or eliminated.

Claims

1. A gas sensor unit for an engine comprising:

a sensor chamber of said unit;

a gas sensor adapted to detect a combustible gas, said gas sensor being disposed in said sensor chamber to detect a density of a particular ingredient of said combustible gas contained in an exhaust gas exhausted from a cylinder of said engine, and to output a detection signal to a control unit; and

means for damping vibration, wherein said means for damping vibration is adapted to support at least one of said gas sensor unit or said combustible gas sensor disposed in said gas sensor unit, such that said gas sensor unit or said combustible gas sensor is movable by an amount equal to or less than a predetermined extent of movement of said engine, thereby to reduce vibration from said engine from transmitting directly to said gas sensor unit or said combustible gas sensor.

2. The gas sensor unit of claim 1, wherein means for damping vibration comprises an elastic supporting member for supporting said gas sensor unit separate from said engine, and

wherein an exhaust gas inlet pipe, which branches and extends from an exhaust pipe of said engine, is connected to said gas sensor unit to conduct said exhaust gas into said sensor chamber.

3. The gas sensor unit of claim 2, wherein said elastic supporting member comprises a ring-shaped, hanging band made of an elastic material, said hanging band hanging said gas sensor unit from said engine.

4. The gas sensor unit of claim 1, wherein said gas sensor unit is fixedly mounted onto said engine and,

wherein said means for damping vibration comprises an elastic supporting member, which supports said gas sensor separate from an inner wall of said sensor chamber.

5. The gas sensor unit of claim 4, wherein said elastic supporting member comprises a vibration-damping spring.

6. The gas sensor unit of claim 5, wherein said vibration damping spring is adapted to support at least a top side and a base side of said gas sensor in two directions from said inner wall of said sensor chamber.

7. The gas sensor unit of claim 4, wherein said gas sensor unit is fixedly attached to and integral with a carburetor of said engine and

wherein an exhaust gas return passageway adapted to return to said carburetor, at least a portion of said exhaust gas introduced into said sensor chamber.

8. The gas sensor unit of claim 5, wherein said gas sensor unit is fixedly attached to and integral with a carburetor of said engine and

wherein an exhaust gas return passageway adapted to return to said carburetor, at least a portion of said exhaust gas introduced into said sensor chamber.

9. The gas sensor unit of claim 6, wherein said gas sensor unit is fixedly attached to and integral with a carburetor of said engine and

wherein an exhaust gas return passageway adapted to return to said carburetor, at least a portion of said exhaust gas introduced into said sensor chamber.

10. The gas sensor unit of claim 1, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

11. The gas sensor unit of claim 2, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

12. The gas sensor unit of claim 3, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

13. The gas sensor unit of claim 4, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

14. The gas sensor unit of claim 5, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

15. The gas sensor unit of claim 6, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

16. The gas sensor unit of claim 7, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

17. The gas sensor unit of claim 8, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

18. The gas sensor unit of claim 9, wherein said gas sensor comprises a combustible gas sensor comprising a platinum coil as a sensing element.

19. An engine comprising a gas sensor unit for an engine, said gas sensor unit comprising:

a sensor chamber of said unit;

a gas sensor adapted to detect a combustible gas, said gas sensor being disposed in said sensor chamber to detect a density of a particular ingredient of said combustible gas contained in an exhaust gas exhausted from a cylinder of said engine, and to output a detection signal to a control unit; and

means for damping vibration, wherein said means for damping vibration is adapted to support at least one of said gas sensor unit or said combustible gas sensor disposed in said gas sensor unit, such that said gas sensor unit or said combustible gas sensor is movable by an amount equal to or less than a predetermined extent of movement of said engine, thereby to reduce vibration from said engine from transmitting directly to said gas sensor unit or said combustible gas sensor.

20. The engine of claim 19, wherein said gas sensor unit is fixedly attached to and integral with a carburetor of said engine and wherein an exhaust gas return passageway adapted to return to said carburetor, at least a portion of said exhaust gas introduced into said sensor chamber.