Exhaust gas sensor

• US 20060042946A1
• Filed: 08/25/2005
• Published: 03/02/2006
• Est. Priority Date: 08/25/2004
• Status: Active Grant

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Ozawa, Shigeyuki, Nonaka, Isao, Tsukahara, Koju
• Granted Patent: US 8,016,989 B2
• Time in Patent Office: Days
• US Class Current: 204/424
• CPC Class Codes: G01N 27/4077 Means for protecting the electrolyte or the electrodes

Abstract

An exhaust gas sensor inhibits a detecting part of an exhaust gas sensor from being exposed to water and has high detection accuracy and high durability. The exhaust gas sensor has a sensor body and a protective cover. The sensor body has an outer housing. The outer housing has a plurality of gas inlets. A gas detection element for detecting a component of the exhaust gas (e.g., oxygen) disposed within the outer housing. The protective cover has a cylindrical shape and has a plurality of protrusions at its opposing ends. The protrusions provide a tight fit with the outer housing. The protective cover is attached to the outer periphery of the outer housing without closing gas inlets formed through the outer cylinder by press-fitting the outer cylinder into the protective cover.

Claims

1. An exhaust gas sensor for an exhaust system, the exhaust sensor comprising a gas detection element configured to detect an amount of a substance in a gas, an outer housing having a plurality of gas inlets, the gas inlets providing fluid communication through the outer housing, the gas detection element positioned within the outer housing, and a protective cover covering and surrounding the outer housing.

2. The exhaust gas sensor of claim 1, wherein the protective cover is coupled to the outer housing by inserting the outer housing into the protective cover.

3. The exhaust gas sensor of claim 1, wherein the protective cover is coupled to the outer housing, and at least one gap is formed between the protective cover and the outer housing.

4. The exhaust gas sensor of claim 3, further comprising a fluid passage in which exhaust gases flow through, the fluid passage is defined between the outer housing and the protective cover and extends between the at least one gap and at least one of the plurality of gas inlets of the outer housing.

5. The exhaust gas sensor of claim 1, wherein the protective cover comprises a cylindrical body with an inner periphery on which a plurality of protrusions are formed circumferentially at substantially equal intervals, and wherein the protrusions couple the protective cover to the outer housing.

6. The exhaust gas sensor of claim 1, wherein the protective cover is made of stainless steel.

7. An exhaust system for a watercraft having an engine, the exhaust system comprising an exhaust conduit, the exhaust conduit having an exhaust gas passage through which exhaust gases discharged from the engine pass, an exhaust sensor comprising a gas detection assembly disposed in the exhaust gas passage, the gas detection assembly comprising a gas detection element configured to detect an amount of a substance in exhaust gases, an outer housing surrounding the gas detection element and having at least one gas inlet, the at least one gas inlet providing fluid communication through the outer housing, and a protective cover surrounding the outer housing.

8. The exhaust system of claim 7, further comprising a gas chamber defined by the gas detection element and the outer housing, the gas chamber being in fluid communication with the at least one gas inlet.

9. The exhaust system of claim 7, further comprising a gas passage defined between the outer housing and the protective cover and extending between the at least one gas inlet and the exhaust gas passage of the exhaust conduit.

10. The exhaust system of claim 7, further comprising at least one gap defined between the outer housing and the protective cover, the at least one gap is in fluid communication with the at least one gas inlet.

11. The exhaust system of claim 10, wherein the protective cover comprises an elongated body that has a plurality of inwardly extending spacers, the spacers are spaced circumferentially along an inner surface of the elongated body and couple the protective cover to the outer housing.

13. The exhaust system of claim 7, wherein the protective cover comprises stainless steel.

14. The exhaust system of claim 7, wherein the protective housing is disposed so as to shield the at least one gas inlet of the outer housing.

15. The exhaust system of claim 7, wherein the exhaust gas sensor is mounted to the exhaust conduit and is positioned between a water-lock and the engine.

12. The exhaust system of 11, wherein the at least one gap is positioned such that exhaust gases pass through the at least one gap before entering the at least one gas inlet, and the at least one gap is formed by the spacers and the outer housing and the protective cover.

16. An exhaust gas sensor for an exhaust system, the exhaust sensor comprising a gas detection element configured to detect an amount of a substance in a gas, an outer housing having at least one fluid passage therethrough, the gas detection element disposed within the outer housing, and a protective cover disposed so as to shield the at least one fluid passage of the outer housing.

17. The exhaust gas sensor of claim 16, wherein the outer housing is coupled to a surface of the gas detection element.

18. The exhaust gas sensor of claim 16, wherein the outer housing has at least one opening inlet defining the at least one fluid passage.

19. The exhaust gas sensor of claim 18, wherein the at least one opening inlet is positioned between opposing ends of the protective cover.

20. The exhaust gas sensor of claim 16, wherein a heater is positioned within the gas detection element, and the heater is adapted to heat the gas detection element to a target temperature for operating the detection element.

21. The exhaust gas sensor of claim 16, wherein the gas detection element is an oxygen sensor.