FUEL PROPERTY SENSOR

• US 20100244857A1
• Filed: 03/24/2010
• Published: 09/30/2010
• Est. Priority Date: 03/24/2009
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: NAKAMURA, Hiroshi, Shikanai, Daisuke, Uchida, Akikazu
• Granted Patent: US 8,159,232 B2
• Time in Patent Office: Days
• US Class Current: 324/663
• CPC Class Codes: G01N 27/226 Construction of measuring vessels; Electrodes therefor

Abstract

In a fuel property sensor, a pair of first and second electrodes is arranged in a fuel chamber to measure an electric capacitance, thereby detecting a mixing ratio of alcohol to gasoline in a fuel of the fuel chamber. An outer wall surface of the first electrode is exposed in the fuel, and a sensing portion contacts an inner wall surface of the first electrode to detect a temperature of the fluid via the first electrode. One end portion of a lead is connected to the sensing portion and the other end portion thereof is connected to a plate portion attached to a housing. Furthermore, an elastic deformation portion is provided as a part of the lead to be elastically deformed, and to cause the sensing portion to be biased in a direction on which the sensing portion contacts the inner wall surface of the first electrode.

Claims

1. A fuel property sensor comprising:

a housing defining a fuel chamber in which a fuel passes;

a pair of first and second electrodes arranged in the fuel chamber to measure an electric capacitance therebetween so as to detect a mixing ratio of alcohol to gasoline in the fuel, the first electrode being located such that an outer wall surface of the first electrode is exposed in the fuel;

a sensing portion contacting an inner wall surface of the first electrode, to detect a temperature of the liquid fluid via the first electrode;

a lead configured to support the sensing portion, the lead having one end portion connected to the sensing portion and the other end portion connected to a plate portion attached to the housing; and

an elastic deformation portion provided as a part of the lead,

wherein the elastic deformation portion is configured to be elastically deformed and to cause the sensing portion to be biased in a direction on which the sensing portion contacts the inner wall surface of the first electrode.

2. The fuel property sensor according to claim 1, wherein

a part of the lead is bent to have a bent portion, and

the elastic deformation portion is configured by the bent portion.

3. The fuel property sensor according to claim 1, further comprising

a holder fixed to the plate member, and disposed to be engaged with the inner wall surface of the first electrode,

wherein the holder has a receiving portion in which the elastic deformation portion is held to be electrically insulated from the first electrode.

4. The fuel property sensor according to claim 3, wherein

the holder has therein a communication passage communicating with the receiving portion, and

the lead penetrates through the communication passage.

5. The fuel property sensor according to claim 1, wherein

the first electrode is provided with an approximately cylindrical wall portion with a bottom, to define therein an inner space partitioned from the fuel in the fuel chamber, and

the sensing portion is disposed in the inner space of the cylindrical wall portion of the first electrode to contact an inner surface of the cylindrical wall portion of the first electrode.

6. The fuel property sensor according to claim 1, wherein

wherein the second electrode is located to opposite to the first electrode.

7. The fuel property sensor according to claim 1, wherein

the second electrode has an approximately cylindrical shape, and

the first electrode is disposed inside of the second electrode.

8. The fuel property sensor according to claim 5, wherein

the sensing portion is disposed to contact the inner surface of the bottom of the cylindrical wall portion of the first electrode, and

the lead extends in the cylindrical wall portion of the first electrode from the sensing portion in an axial direction.

9. The fuel property sensor according to claim 1, further comprising

a circuit element portion which is configured to correct the measured electric capacitance based on the temperature detected by the sensing portion, so as to determine the mixing ratio of the alcohol to the gasoline.