JPS636442Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel heating device for a diesel engine.

As is well known, when diesel fuel consisting mainly of light oil is placed at low temperatures, wax components in the fuel may precipitate. In the case of a diesel engine, a fuel filter device for removing impurities in the fuel is installed in the fuel supply system, similar to a gasoline engine, etc., but in the fuel supply system upstream of this fuel filter device, the above-mentioned If a wax component is deposited, the deposited wax component will be trapped in the filter element of the fuel filter device and will rapidly clog the filter element. When such clogging occurs, the flow of fuel is obstructed in the fuel filter device, making normal operation of the engine impossible.

Therefore, as shown in Japanese Utility Model Application Publication No. 50-88717, for example, a fuel heating device has been conventionally provided which prevents the precipitation of wax components by heating the fuel sent to a fuel filter device.

However, conventional fuel heating devices are equipped with an electric heating element around the oil filter device, or have the fuel flow through a heat exchanger through which hot fluids such as engine cooling water and engine lubricating oil are passed. In other words, thermal fluids such as engine cooling water and engine lubricating oil are passed through a heat exchanger for heating fuel, which requires additional and troublesome electrical wiring work and piping work for thermal fluids. It was something to do.

The precipitation of wax components as described above occurs in cold regions, and as long as the diesel engine is used in a region other than a particularly cold region, a fuel heating device as described above is not necessary. Therefore, it goes without saying that it would be best if this fuel heating device could be easily installed as an option in a normal engine, and the present invention provides a fuel heating device that can be easily installed in an engine. The purpose is to provide

The diesel engine fuel heating device of the present invention is based on the fact that conventionally, engines are often equipped with an oil cooling heat exchanger through which lubricating oil and engine cooling water are circulated and the oil is cooled by the engine cooling water. This was achieved by focusing on the fact that the lubricating oil and engine cooling water that flow through the passages inside the engine receive combustion heat more easily than the fuel, so the temperature rise period is short. The present invention is characterized in that the fuel heating heat exchanger is attached to the engine integrally with the oil cooling heat exchanger in a state where at least one of oil and cooling water flows adjacent to the fuel passage. In other words, structurally, the heat exchanger is additionally installed in the place where the thermal fluid passage for the oil cooling heat exchanger was formed, so there is no need to newly install the thermal fluid supply piping. The only piping work required is to re-piping the fuel supply passage connected to the fuel filter device so that the fuel heating heat exchanger is interposed therein.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a fuel heating device for a diesel engine according to a first embodiment of the present invention, and a second embodiment shows a fuel heating device for a diesel engine according to a first embodiment of the present invention.
The figure is a sectional view thereof. In Fig. 2, the lower part of the heat exchanger is shown rotated by 90 degrees. 1st
As shown in the figure, a mounting bracket 2 is fixed to an engine body 1 such as an engine cylinder block or cylinder head with bolts or the like.
An oil filter 3, an oil cooling heat exchanger 4, and a fuel heating heat exchanger 5 are attached to the mounting bracket 2.
is installed.

The mounting bracket 2 has an oil inlet hole 6 and an oil outlet hole 7, each having one end open to the side surface 2a and the other end open to the upper surface 2b, and when the side surface 2a of the mounting bracket 2 is fixed to the engine body 1. , the oil inlet hole 6 communicates with an oil supply passage 8 that opens on the bracket mounting surface 1a of the engine body 1 and communicates with the high pressure part of the oil passage in the engine body 1, while the oil outlet hole 7 similarly opens on the bracket attachment surface 1a of the engine body 1. Side 1
The oil return passage 9 is opened to a portion a and communicates with an oil return passage 9 which is open to a low pressure part of the oil passage in the engine body 1.

As shown in Fig. 2, the oil filter 3 is constructed by housing a substantially cylindrical filter element 11 in a can-shaped filter case 10, and a hollow mounting bolt 12 with a male thread 12a on the outer periphery of the tip is fixed to the center of the bottom surface. The oil cooling heat exchanger 4 is constructed by stacking two elements in the vertical direction, with the internal space finely divided by partitions 4a, and a through hole is provided in the center. The fuel heating heat exchanger 5 is also constructed of elements having the same structure as the elements of the oil cooling heat exchanger 4, and both of these heat exchangers 4, 5 are
When the oil filter 3 is fixed to the mounting bracket 2 by screwing and fastening its mounting bolt 12 into the female thread 2c formed on the inner surface of the large-diameter opening of the oil inlet hole 6, the mounting bolt 12 is passed through the central through hole and fastened together with the oil filter 3 to the mounting bracket 2.

In this way, the oil filter 3, heat exchanger 4,
5 is integrally fixed to the mounting bracket 2,
Filter element 11 of oil filter 3
The inside communicates with the oil inflow hole 6 via a hollow mounting bolt 12 . Therefore, the engine lubricating oil supplied from the high-pressure part of the oil passage in the engine body 1 permeates from the inside to the outside of the filter element 11 as shown by the solid line arrow in FIG. The filter element 11 traps impurities.

The lubricating oil that has been purified by passing from the inside to the outside of the filter element 11 flows out of the filter case 10 from the communication hole 10a provided at the bottom of the filter case 10, and flows through the annular ring of the oil cooling heat exchanger 4. A space 14 defined between the contact portion (protrusion) 4b and the bottom surface of the filter case 10
The oil then flows into the lubricating oil passage 4d of the heat exchanger 4 through the communication hole 4c. This lubricating oil passage 4d is formed by a flat small chamber partitioned by a partition wall 4a and partially communicating with each other through a communication hole 4f, and the lubricating oil flows in a detour in this lubricating oil passage 4d. After that, it flows out of the oil cooling heat exchanger 4 from the communication hole 4g. The partition wall 4
In the portion separated from the lubricating oil passage 4d by a, the laminated small chambers are partially communicated with each other by a communication hole 4h to form a cooling water passage 4k, and one end of the cooling water passage 4k has a cooling water inlet. The hole 15 communicates with the other end, and the cooling water outlet hole 16 communicates with the other end. The cooling water inflow hole 15 and the outflow hole 16 are connected to the high pressure section and the low pressure section of the engine cooling water passage, respectively, through piping (not shown), so that the engine cooling water flows through the second
As shown by the broken line arrow in the figure, the cooling water flows into the cooling water passage 4k from the cooling water inflow hole 15, flows through the passage 4k, and flows out from the cooling water outflow hole 16. At this time, the engine lubricating oil exchanges heat with the cooling water through the partition wall 4a, and when the lubricating oil is at a higher temperature than the cooling water (eg, 80° C. or higher), it is cooled by the cooling water. This suppresses the temperature rise of the lubricating oil, prevents the oil viscosity from decreasing more than necessary and prevents oil properties from deteriorating.

As mentioned above, the lubricating oil that has flowed out of the oil cooling heat exchanger 4 from the communication hole 4g is transferred to the annular contact portion (protrusion) at the lower end of the oil cooling heat exchanger 4.
4l and an annular contact part (protrusion) 5b at the upper end of the fuel heating heat exchanger 5 that contacts the relevant contact part 4l, from the space 17 defined through the communication hole 5c. It flows into the lubricating oil passage 5d of the heat exchanger 5. This lubricating oil passage 5d is formed in the same manner as the lubricating oil passage 4d of the oil cooling heat exchanger 4, and the lubricating oil that has flowed therein passes through the communication hole 5e, takes a detour through the lubricating oil passage 5d, and reaches the lower end. It flows out of the heat exchanger 5 through a communication hole 5h formed inside the annular contact portion (protrusion) 5g. The lubricating oil that has flowed out into the space 18 defined between the corresponding contact portion 5g and the mounting bracket 2 flows into the oil outflow hole 7 opened in the annular groove 2d formed around the oil inflow hole 6, and then flows into the engine. The oil flows back into the oil passage in the main body 1. In the portion separated from the lubricating oil passage 5d by the partition wall 5a, the laminated small chambers are partially communicated with each other by a communication hole 5k to form a fuel passage 5l, and a fuel inlet hole 19 is provided at one end of the passage 5l.
A fuel outflow hole 20 is communicated with the other end.

FIG. 3 shows a fuel supply system connected to the fuel inflow hole 19 and fuel outflow hole 20.
As shown in FIG. 3, diesel fuel in a fuel tank (not shown) is sent to an electromagnetic switching valve 23 via a pipe 21. As shown in FIG. A sedimenter 22 is interposed in the pipe 21, and moisture mixed in the fuel is separated in the sedimenter 22. A solenoid 23c that drives a plunger 23b to which a valve body 23a of an electromagnetic switching valve 23 is fixed is connected to a temperature switch 24 and a key switch 2 arranged in series.
5 to a battery power supply 26.
One outflow hole 23d of the electromagnetic switching valve 23 is connected to the pipe 27.
The fuel filter 28 is connected to a fuel injection pump 30 via a pipe 29. The other outlet hole 23e of the electromagnetic switching valve 23 is communicated with the fuel inlet hole 19 of the fuel heating heat exchanger 5 via a pipe 31, and the fuel outlet hole 20 of the heat exchanger 5 is connected to a pipe 32. The pipe 32 is connected to the pipe 27.

When the solenoid 23c is not energized, the plunger 23b is in the position shown in FIG. . In this way, when flowing through the fuel heating heat exchanger 5, the fuel passes through the partition wall 5a,
Because it is heated by the lubricating oil, which is hotter than the fuel due to the influence of engine combustion heat,
If a wax component is precipitated in the fuel, that wax component is melted, and furthermore, the wax component precipitation downstream of the heat exchanger 5 is also prevented. Therefore, fuel without deposited wax components is sent to the fuel filter 28, and the filter element of the fuel filter 28 is prevented from being clogged with the deposited wax components. The temperature switch 24 is an electromagnetic switching valve 23
The device detects the temperature of the fuel sent to the device and opens and closes depending on the temperature.
40℃ or higher). Therefore, when there is no risk of wax component detection (of course, when the engine is running and the key switch 25 is closed), the solenoid 23c is energized and the plunger 23b is pulled upward in the figure. It will be done. Therefore, the fuel is sent directly to the fuel filter 28 via the pipe 27 without passing through the heat exchanger 5.

The fuel heating heat exchanger 5 can be constructed by using a type with long mounting bolts 12 as the oil filter 3, or by using a type with long mounting bolts 12.
By simply replacing the oil cooling heat exchanger 4 with a longer one, the oil cooling heat exchanger 4 is integrated with the oil filter 3 and the mounting bracket 2. Since the thermal fluid of the oil cooling heat exchanger 4 is used as the oil, there is no need to newly provide piping for the thermal fluid.

In the embodiment described above, the present invention is applied to a diesel engine in which the oil cooling heat exchanger is installed outside the engine body, but in relatively large diesel engines, the oil cooling heat exchanger is attached to the engine body. The present invention is also applicable to such types of diesel engines. 4 and 5 show a second embodiment of the present invention applied to such a diesel engine.

As shown in FIG. 4, a mounting bracket 51 is fixed to the side of a cylinder block 50 constituting the engine body, and an oil filter 52 similar to the oil filter 3 in the first embodiment is mounted on the mounting bracket 51. is supported. As shown in the plan sectional view of FIG. 5, the mounting bracket 51 has an opening 50b formed in the side wall of the cylinder block 50 so as to open into a water jacket (cooling water passage) 50a inside the cylinder block 50.
is attached so as to close it from the outside. A fuel heating heat exchanger 53 is fixed to the inner wall of the mounting bracket 51, and an oil cooling heat exchanger 54 is further integrally fixed to the fuel heating heat exchanger 53. Oil cooling heat exchanger 54
These include an oil inflow pipe 57 and an oil outflow pipe 58 that contact the water jacket inner wall 50c of the cylinder block 50 and communicate with an oil supply passage 55 and an oil return passage 56 provided in the cylinder block 50, respectively; The lubricating oil that flows from the oil inflow pipe 57 to the oil filter 52 and the lubricating oil that is purified in the oil filter 52 and then flows back through the oil outflow pipe 58 are connected to the water jet. Heat is exchanged with the engine cooling water flowing inside the bucket 50a.

Hereinafter, this heat exchange between lubricating oil and engine cooling water will be explained with reference to FIG. 6. FIG. 6 shows general temperature rise characteristics of engine cooling water, lubricating oil, and fuel in a diesel engine. Because engine cooling water flows around the combustion chamber, it is easily affected by combustion heat, and its temperature rises faster than lubricating oil. After the thermostat opens, the temperature does not rise much after the overshoot period during which the valve opens is over and the radiator begins to cool the temperature. On the other hand, lubricating oil receives the temperature of the cylinder block, cylinder head, and crank chamber as well as the sliding heat of each part, but because it receives combustion heat indirectly, its temperature rises more slowly than engine cooling water. However, the temperature of this lubricating oil increases over time, and the temperature of the lubricating oil gradually becomes higher than that of the engine cooling water. Therefore, during the transient period when the lubricating oil temperature is lower than the coolant temperature (period before time _t1 in FIG. 6), the lubricating oil is heated by the engine coolant in the heat exchanger 54 and becomes hotter. This reduces the viscosity of the oil and improves its lubrication performance. Then, when the lubricating oil temperature becomes higher than the cooling water temperature after time _t1 in FIG. Deterioration is prevented.

The fuel heating heat exchanger 53 includes a fuel passage 53a shaped like a flat small chamber, an oil inflow passage 51a of the mounting bracket 51, which extends inside the fuel passage 53a and communicates with the oil inflow pipe 57 and the oil outflow pipe 58, respectively. Oil inflow passage 53b and oil outflow passage 53 communicating with oil outflow passage 51b
c, and the fuel passage 53
A fuel inflow hole 60 and a fuel outflow hole 61 are communicated with a.

A fuel supply system as shown in FIG. 3, for example, is connected to the fuel inlet hole 60 and fuel outlet hole 61, and when the temperature of the diesel fuel is low, it passes through the fuel heating heat exchanger 53 and then passes through the fuel filter. sent to. The fuel flowing through the fuel passage 53a in the heat exchanger 53 is heated from the surroundings by the engine cooling water flowing in the water jacket 50a, and the fuel flowing through the oil inflow passage 53b and the oil outflow passage 53 in the fuel passage 53a is heated by the engine cooling water flowing in the water jacket 50a.
It is heated by the lubricating oil flowing through c. In other words, since the fuel flows through the fuel injection pump and piping installed outside the engine, it is less affected by combustion heat, and the temperature is mainly influenced by the outside air temperature. The temperature is lower than that of the engine cooling water and lubricating oil. The fuel is therefore heated by both engine cooling water and lubricating oil as described above. By heating the fuel in this way, precipitation of the wax component in the fuel is prevented, and the precipitated wax component is melted, and the heat exchanger 53
Clogging of filter elements in downstream fuel filters is prevented.

Also in this second embodiment, since the fuel heating heat exchanger 53 is integrally formed with the oil cooling heat exchanger 54, the fuel can be heated without the need to newly provide thermal fluid piping for fuel heating. It's becoming possible.

As explained above in detail, the diesel engine fuel heating device of the present invention heats the fuel using the fuel heating heat exchanger that is integrated with the oil cooling heat exchanger. There is no need to install new thermal fluid piping, and the fuel supply piping can be easily installed in the engine by making some modifications to the fuel supply piping, making it ideal as an optional fuel heating device.

[Brief explanation of drawings]

Fig. 1 is a side view showing the first embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the first embodiment, and Fig. 3 shows a fuel supply system incorporating the fuel heating device of the first embodiment. 4 is a perspective view showing a second embodiment of the present invention, FIG. 5 is a plan cross-sectional view of the second embodiment, and FIG. 6 is a diagram showing engine cooling water, lubricating oil, and fuel according to the present invention. 3 is a graph showing an example of temperature increase characteristics. 1... Engine body, 4, 54... Oil cooling heat exchanger, 4d, 5d... Lubricating oil passage, 4
k...Cooling water passage, 5, 53...Fuel heating heat exchanger, 5l, 53a...Fuel passage, 15...Cooling water inflow hole, 16...Cooling water outflow hole, 19,60...
... Fuel inflow hole, 20, 61 ... Fuel outflow hole, 50
...Cylinder block, 50a...Water jacket, 57...Oil inflow hole, 58...Oil outflow hole.

Claims (1)

[Claims for Utility Model Registration] (1) In a diesel engine in which an oil cooling heat exchanger having a lubricating oil passage is installed adjacent to the lubricating oil passage in a state in which engine cooling water flows, the fuel passage A fuel heating heat exchanger having a fuel heating heat exchanger is attached to the engine integrally with the oil cooling heat exchanger with at least one of oil and cooling water flowing adjacent to the fuel passage, and A fuel heating device for a diesel engine that forms a fuel supply passage that supplies fuel to a fuel filter via an exchanger. (2) The oil cooling heat exchanger and the fuel heating heat exchanger are integrated between a mounting bracket that has an oil inflow hole and an oil outflow hole and is attached to the engine, and a filter case of the oil filter. Utility model registration claim 1, characterized in that an oil passage is formed in which the oil flowing in from the oil inflow hole of the mounting bracket passes through an oil filter and both heat exchangers and reaches the oil outflow hole. Fuel heating device for the diesel engine described. (3) The oil cooling heat exchanger is disposed within the water jacket of the engine, and the fuel heating heat exchanger is disposed integrally with the oil cooling heat exchanger within the water jacket. A fuel heating device for a diesel engine according to claim 1, characterized in that it is a utility model.