JPS6146208Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a fuel filter device in a diesel engine fuel supply system.

Light oil, which is the fuel for diesel engines, has a higher pour point than gasoline, so when the atmospheric temperature is low in winter or in cold regions, wax in the light oil precipitates and adheres to the filter element of the fuel filter device. There is a problem in that this causes clogging and causes the engine to stop.

In order to solve this problem, a fuel tank with a structure that allows return fuel with a higher temperature to be supplied to the engine from the feed pump as much as possible, a bypass valve that bypasses the filter element in the fuel filter device, a fuel pipe and a Measures such as attaching a heater to the filter device to heat the fuel have been taken, but
The second means cannot prevent wax from being deposited in the fuel, nor can it prevent the deposited wax from gradually adhering to the filter element at low temperatures. Furthermore, the method of attaching a heater to the fuel pipe or fuel filter device is to melt the deposited wax by heating light oil, but the capacity of the heater is limited and it is impossible to completely prevent wax deposition. It is difficult to raise the temperature of the fuel to the point where the fuel temperature reaches the desired temperature, and therefore, under severe weather conditions, there is a problem in that the filter element may become clogged due to wax precipitation.

This invention was made in view of the above-mentioned conventional problems, and it is possible to melt deposited wax adhering to the filter element using a heating member with a small heat capacity, thereby preventing clogging of the filter element. The object of the present invention is to provide a fuel filter device for a diesel engine.

This device arranges a heating member integrally with the filter element or close to its fuel inlet side, detects the fuel pressure difference between the fuel inlet side and the fuel outlet side of the filter element, and detects the fuel pressure difference when the pressure difference exceeds a certain value. The above object is achieved by providing a control device that turns on the heating member when the heating member is turned on.

Further, this invention achieves the above object by constructing the heating member in the fuel filter device for the diesel engine as a plate-shaped PTC element having a plurality of fuel passage through holes.

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, as shown in FIGS. 1 to 3, a heating member 3 is embedded integrally with a filter element 2 of a fuel filter device 1 of a diesel engine.

This heating member 3, as shown in FIG.
Plate-shaped PTC with multiple through holes 4 for fuel passage
The filter element 2 is curved to match the curved shape of the filter element 2.

The heating member 3 made of this PTC element has a fourth
As shown in the figure, the filter element 2
The fuel pressure difference between the fuel inlet pipe 5 and the fuel outlet pipe 6 is detected, and power is supplied from the battery 8 via the pressure switch 7 which is turned on when this pressure difference exceeds a certain value. I got a fever,
The filter element 2 is heated. Reference numeral 9 in the figure indicates an on/off switch for the power supply circuit of the heating member 3, reference numeral 10 in FIG. 1 indicates a collar for supporting the filter element 2, and reference numeral 11 indicates a fuel filter case.

In this embodiment, when the fuel passing through the filter element 2 of the fuel filter device causes a temperature drop and deposits wax, and when this wax adheres to the filter element 2, the fuel inlet pipe 5 on the upstream side of the filter element 2 Since the fuel pressure difference in the fuel outlet pipe 6 on the downstream side becomes large, the clogging state of the filter element 2 due to wax is detected by the pressure difference, and the pressure switch 7 is turned on. 3 is energized from a battery 8 to generate heat, and the wax adhering to the filter element 2 is directly heated and melted.

Therefore, there is no waste such as heating light oil that does not contain wax, and the battery 8 that is the power source for the heating member 3 only needs to have a small capacity. Furthermore, since the heating member 3 is automatically turned on by detecting the pressure difference between the inlet and outlet sides of the filter element 2, which increases due to wax deposition, an unexpected engine stop can be prevented.

In the above embodiment, the heating member 3 is disposed integrally embedded in the filter element 2, but the heating member 3 may be of any type as long as it can directly melt the wax adhering to the filter element 2. Therefore, the heating element may be arranged close to the entrance surface of the filter element 2, as shown in FIG. 5 or 6.

In the case of these second and third embodiments, since the heating member 3 is arranged separately from the filter element 2, there is an advantage that manufacturing is easy.

Further, in the above embodiment, the PTC element is formed into a plate shape, but the present invention is not limited to this, and includes cases where the PTC element is formed into other shapes such as a grid shape.

However, if the PTC element is formed into a plate shape as shown in FIG. 3, it has the advantage of being easy to manufacture.

Further, in the above embodiment, the heating member is formed of a PTC element, but it may be other heating means. However, the PTC element has the advantage of being easy to configure and control.

Furthermore, the heating member 3 is energized by a battery 8 that is turned on and off by a pressure switch 7, and the filter element 2
Since it can be turned on and off according to the clogging state of the fuel, it has the advantage that more effective control can be performed compared to the case where it is turned on and off at a constant temperature regardless of the wax component content of the fuel.

Since the present invention is configured as described above, it is possible to directly melt the wax deposited in the fuel that adheres to the filter element, and therefore, it is possible to reliably prevent clogging of the filter element using a small-capacity heating member. It has the excellent effect of being able to

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing an embodiment of a fuel filter device for a diesel engine according to the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. FIG. 4 is an enlarged perspective view showing the heating member; FIG. 4 is a circuit diagram including a partial piping diagram showing the circuit for the heating member of the same embodiment; FIGS. 5 and 6 are
The figure is a sectional view similar to FIG. 2 showing second and third embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Fuel filter device, 2... Filter element, 3... Heating member, 4... Fuel passage through hole, 5... Fuel inlet pipe, 6... Fuel outlet pipe, 7... Pressure switch, 8...Battery.

Claims (1)

[Claims for Utility Model Registration] (1) A heating member is disposed integrally with the filter element or close to its fuel inlet side, and
A fuel filter for a diesel engine, characterized in that a pressure switch is provided that detects a fuel pressure difference between a fuel inlet side and a fuel outlet side of the filter element and turns on the heating member when this pressure difference exceeds a certain value. Device. (2) The fuel filter device for a diesel engine according to claim 1, wherein the heating member is constituted by a plate-shaped PTC element having a plurality of fuel passage through holes.