JPH0127855Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a filter element of a fuel filter incorporated in a liquid fuel supply system of an internal combustion engine or the like.

A liquid fuel supply system of an internal combustion engine has a fuel filter in the middle thereof, and the fuel filter is configured to trap solid foreign matter in the liquid fuel by a filter element.

Light oil, which is the fuel for diesel engines, has a high wax content, and wax precipitates at low temperatures. Therefore, in the fuel filter built into the liquid fuel supply system of a diesel engine, the wax that precipitates at low temperatures causes the filter to The element may become clogged. For this reason, in diesel engines, when the filter element is clogged with wax at low temperatures, the required amount of liquid fuel is not supplied to the diesel engine, and the cold startability and driveability of the diesel engine are significantly impaired. There is.

In view of the above-mentioned problems, the present invention aims to provide a filter element for a fuel filter that prevents the deposition of wax in liquid fuel at low temperatures and does not cause clogging due to wax.

This object is achieved according to the invention by a fuel filter element having heater conductors inside an electrically insulating ceramic having a porous structure.

In the fuel filter element according to the present invention, the heater wire inside the electrically insulating ceramic is energized to generate heat.
This directly heats the electrically insulating ceramic that acts as a filter.

As a result, even if the liquid fuel supplied to the filter element has wax deposited on it, the wax will not be heated and melted, and this will not adhere to the filter element and cause clogging of the filter element.

Since the heater lead wire is provided inside the electrically insulating ceramic, the heater lead wire is held by the ceramic, and there is no need to provide a special support for holding the heater lead wire.

In addition, even if wax deposited in the fuel adheres to the filter element when starting the engine, the filter element itself generates heat when the heater conductor is energized, which quickly dissolves the deposited wax. However, there is no delay in the supply of fuel to the internal combustion engine due to clogging of the filter element, and retarded startability of the internal combustion engine is not deteriorated due to clogging of the filter element.

In addition, as the liquid fuel is heated as it passes through the filter element, a higher temperature liquid fuel than before is supplied to the internal combustion engine.
This promotes atomization and vaporization of the liquid fuel and improves ignitability.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the figure, 1 indicates a cup-shaped filter case, and 2 indicates a cover provided to close the opening of the filter case 1. An annular filter element 3 is provided inside the filter case 1, and the filter element defines a dirty sand 4 on the outside and a clean sand 5 on the inside. The cover 2 has a fuel inlet 6 communicating with the dirty side 4 and a fuel inlet 7 communicating with the clean side 5.

The filter element 3 is entirely composed of electrically insulating ceramics 8 having a porous structure, and has a heater conductor 9 made of tungsten, molybdenum, etc. printed therein, and this heater conductor 9 is energized. This is causing fever. The ceramic 8 is made of highly electrically insulating ceramic such as alumina ceramic, and the pore diameter of its porous structure is approximately 5 to 20 microns. Annular metal end plates 10 and 11 are attached to both end surfaces of the filter element 3, and each of these serves as an electrode plate for the heater conductor 9. It is electrically conductively connected to a connecting terminal 14 attached to the spring receiving member through the spring receiving member. Note that the spring receiving member 13 and the connecting terminal 14 are connected to the insulating member 15.
It is electrically insulated from the filter case 1 by. The end plate 11 is conductively connected to the cover 2 and grounded.

Further, a temperature sensor 16 such as a thermocouple is attached to the cover 2.
The sensor senses the temperature of the fuel that has passed through the filter element 3, and thereby controls the energization of the heater conductor 9 to prevent excessive heating of the fuel.

The energization of the heater conductor 9 may be controlled according to the fuel temperature detected by the temperature sensor 16 and the temperature in the engine room, and only when the temperature in the engine room is below a predetermined value and the fuel temperature is above a predetermined value. It suffices if the heater conductive wire 9 is energized.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and those skilled in the art will recognize that various embodiments are possible within the scope of the present invention. It would be obvious to

[Brief explanation of drawings]

The accompanying drawing is a longitudinal cross-sectional view of one embodiment of a fuel filter equipped with a filter element according to the present invention. 1...Filter case, 2...Cover, 3...
Filter element, 4... Dirty side, 5
... Clean sand, 6 ... Fuel inlet, 7 ... Fuel outlet, 8 ... Porous ceramics, 9 ... Heater conductor wire, 10, 11 ... End plate, 12 ... Mounting spring, 13 ... Spring receiving member , 14... connection terminal,
15... Insulating member, 16... Temperature sensor.

Claims (1)

[Scope of utility model registration request] A fuel filter element that has a heater conductor wire inside electrically insulating ceramics with a porous structure.