Fuel-aspect sensor

• US 8,593,162 B2
• Filed: 12/14/2009
• Issued: 11/26/2013
• Est. Priority Date: 12/19/2008
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Nakamura, Hiroshi, Uchida, Akikazu
• Primary Examiner(s): Vazquez, Arleen M
• Assistant Examiner(s): BROWN, LAMARR A
• Application Number:
  US12/637,237
• Publication Number:
  US 20100156443A1
• Time in Patent Office: 1,443 Days
• Field of Search: 324/663, 324/698, 324/665, 324/670, 324/684, 324/685, 324/686, 324/690, 73/500.1, 73/530.5, 731/144.3, 731/144.1
• US Class Current: 324/663
• CPC Class Codes: F02D 19/0628 Determining the fuel pressure, temperature or flow, the fuel tank fill level or a valve position
• CPC Class Codes: F02D 19/0634 Determining a density, viscosity, composition or concentration F02D19/087 takes precedence
• CPC Class Codes: F02D 19/084 Blends of gasoline and alcohols, e.g. E85
• CPC Class Codes: F02D 2200/0606 Fuel temperature
• CPC Class Codes: F02D 2200/0611 Fuel type, fuel composition or fuel quality
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: G01N 33/2852 Alcohol in fuels
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

An object of the invention is to provide a fuel-aspect sensor having higher detection accuracy. A first electrode is inserted into a hole formed in a first housing member. A cylindrical second electrode is inserted into and firmly fixed to the first electrode by a cylindrical insulating member. A first elastic member, for example, made of rubber, is arranged between the first electrode and a second housing member. The first electrode has a large-diameter portion, which is biased by the first elastic member toward a sealing surface formed on an inner wall of the hole, so as to fluid-tightly seal a space between the first electrode and the second housing member.

Claims

1. A fuel-aspect sensor for detecting aspects of mixed fuel, which is mixture of different fuels respectively having different specific inductive capacities, comprising:

a first housing member having a fuel chamber through which the mixed fuel flows and an insertion hole for communicating the fuel chamber with outside of the first housing member, the insertion hole having an open end at which a stepped portion is formed;

a first electrode inserted into the insertion hole from the open end of the insertion hole, the first electrode having an inside space being in communication with the fuel chamber, the first electrode having a flanged portion extending in a radial direction of the first electrode so that the flanged portion is inserted into the stepped portion of the insertion hole;

a second electrode having a closed bottom portion, a lower part of the second electrode being accommodated in the inside space of the first electrode, so that an outer surface of the second electrode is exposed to the mixed fuel introduced into the inside space of the first electrode;

an insulating member for electrically insulating the first and second electrodes from each other and for firmly fixing the first and second electrodes to each other;

a temperature sensor accommodated in the second electrode and fixed to an inside surface of the closed bottom portion thereof for detecting temperature of the mixed fuel;

a second housing member firmly attached to the first housing member for closing the open end of the insertion hole of the first housing member;

an electronic control unit accommodated in the second housing member and electrically connected to the first electrode, the second electrode, and the temperature sensor, for detecting electrostatic capacity between the first and second electrodes, to thereby detect the aspects of the mixed fuel based on the electrostatic capacity and the temperature of the mixed fuel; and

an elastic member disposed between the second housing member and the first electrode for biasing the flanged portion of the first electrode toward a sealing surface of the first housing member, which is formed at an inner wall of the insertion hole , so that the flanged portion is in contact with the sealing surface,

wherein a diameter of the elastic member is larger than that of the flanged portion of the first electrode,

wherein the stepped portion comprises a first vertical surface, a first stepped surface, a second vertical surface, and a second stepped surface, and

wherein the flanged portion comprises a first diameter portion and a second diameter portion, in which the second diameter portion is larger than the first diameter portion.

2. The fuel-aspect sensor according to the claim 1, wherein

the elastic member is made of such material having coefficient of thermal conductivity smaller than those of the second housing member and the first electrode.

3. The fuel-aspect sensor according to the claim 1, wherein

the sealing surface of the first housing member is formed as a stepped surface at the inner wall of the insertion hole, which is perpendicular to a direction in which the first electrode is biased by the elastic member.

4. The fuel-aspect sensor according to the claim 1, wherein

the elastic member is accommodated in a recess formed at an outer bottom surface of the second housing member, and

a circular hole is formed in the elastic member, through which an open-end side of the second electrode is inserted, so that an inner surface of the circular hole is fluid-tightly in contact with a radially-outward wall of the open-end side of the second electrode.

5. The fuel-aspect sensor according to the claim 1, wherein

the insulating member is formed in a cylindrical shape, and

a ring-shaped elastic member is arranged at a position, which is away from the insulating member in a radially-outward direction thereof, and the ring-shaped elastic member being arranged between the first electrode and the first housing member.

6. The fuel-aspect sensor according to the claim 1, further comprising:

fuel pipes for supplying the fuel into the fuel chamber and discharging the fuel from the fuel chamber.

7. A fuel-aspect sensor for detecting aspects of mixed fuel, which is mixture of different fuels respectively having different specific inductive capacities, comprising:

a first housing member having a fuel chamber through which the mixed fuel flows and an insertion hole for communicating the fuel chamber with outside of the first housing member, the first housing member having a first axial end connected to a first fuel pipe to be connected to a fuel tank and a second axial end connected to a second fuel pipe to be connected to an engine;

a first electrode inserted into the insertion hole from an open end of the insertion hole, the first electrode having an inside space being in communication with the fuel chamber;

a second electrode having a closed bottom portion, a lower part of the second electrode being accommodated in the inside space of the first electrode, so that an outer surface of the second electrode is exposed to the mixed fuel introduced into the inside space of the first electrode;

an insulating member for electrically insulating the first and second electrodes from each other and for firmly fixing the first and second electrodes to each other;

a temperature sensor accommodated in the second electrode and fixed to an inside surface of the closed bottom portion thereof for detecting temperature of the mixed fuel;

a second housing member firmly attached to the first housing member for closing the open end of the insertion hole of the first housing member;

an electronic control unit accommodated in the second housing member and electrically connected to the first electrode, the second electrode, and the temperature sensor, for detecting electrostatic capacity between the first and second electrodes, to thereby detect the aspects of the mixed fuel based on the electrostatic capacity and the temperature of the mixed fuel; and

an elastic member disposed between the second housing member and the first electrode for biasing the first electrode toward a sealing surface of the first housing member, which is formed at an inner wall of the insertion hole so as to oppose to the open end of the hole.