Device for protecting a lambda probe

• US 4,903,481 A
• Filed: 12/19/1988
• Issued: 02/27/1990
• Est. Priority Date: 12/19/1987
• Status: Expired due to Fees

• Current Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Inventors: Wollenhaupt, Gottfried, Schuster, Hans-Dieter
• Primary Examiner(s): Hart, Douglas
• Application Number:
  US07/286,164
• Time in Patent Office: 435 Days
• Field of Search: 60/276, 204/428
• US Class Current: 60/276
• CPC Class Codes: G01N 27/4077 Means for protecting the electrolyte or the electrodes

Abstract

Thermal shock reactions of a heated lambda probe owing to the impact of liquid droplets on the heated ceramic probe body during cold starting, which phenomenon can lead to a fracture of the ceramic probe body, are avoided, and a better representativeness of the signals transmitted by the lambda probe is achieved, in that a gas deflector plate is arranged before the lambda probe in the exhaust gas flow, as seen in the direction of flow of the exhaust gases, in such a way that the lambda probe lies in its Lee.

Claims

1. Device for prolonging the service life and improving the representativeness of the measurements of a heated lambda probe arranged in the exhaust gas flow of an internal combustion engine, wherein a gas deflector plate means is arranged upstream of and separated from the lambda probe in the exhaust gas flow as seen in the direction of flow of the exhaust gases, for deflecting the exhaust gas and water particles therein, and wherein the lambda probe is located in a lee of the exhaust gas deflector plate means and downstream thereof whereby the lambda probe is protected from impingement of the water particles in the exhaust gas which are deflected sufficiently to pass by the probe.

2. Device according to claim 1, wherein the gas deflector plate means has a width of 80 to 180% of a basket guard diameter of the lambda probe, and is arranged 5 to 30 nm before the lambda probe.

3. Device according to claim 1, wherein the length of the gas deflector plate means amounts to 80 to 120% of the length of the part of the lambda probe reaching into the exhaust gas flow.

4. Device according to claim 1, wherein the gas deflector plate means is formed convexly, as seen in the direction of flow of the exhaust gases.

5. Device according to claim 2, wherein the length of the gas deflector plate means amounts to 80 to 120% of the length of the part of the lambda probe reaching into the exhaust gas flow.

6. Device according to claim 2, wherein the gas deflector plate means is formed convexly, as seen in the direction of flow of the exhaust gases.

7. Device according to claim 3, wherein the gas deflector plate means is formed convexly, as seen in the direction of flow of the exhaust gases.

8. Device according to claim 5, wherein the gas deflector plate means is formed convexly, as seen in the direction of flow of the exhaust gases.