JPH0584808B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil supply system for improving the starting performance of an internal combustion engine, particularly a diesel engine, at low temperatures.

[Conventional technology and its problems]

Conventional diesel engines have poor starting characteristics at low temperatures, and it takes a considerable amount of time to reach a stable rotational speed. One of the reasons for this is thought to be that the viscosity of engine oil increases significantly at low temperatures, which significantly increases the driving resistance of the oil pump.

[Means for Solving the Problems] The present invention aims to solve the problems in the prior art, and the present invention improves the efficiency of the oil pump by keeping the viscosity of the oil sucked into the oil pump low during cold startup. This reduces driving resistance, thereby shortening the time it takes for the engine to reach stable rotation.

That is, this object is to provide an oil for an internal combustion engine, which is characterized in that a means for restricting the flow rate of oil and a means for heating the oil are provided on the suction side of an oil pump in a circulation system that supplies oil to the internal combustion engine. This is achieved through a feeding system.

This system will be explained based on a typical pipe diagram of the present invention shown in FIG.

Oil for engine lubrication is stored in an oil tank 1, and by the action of an oil pump 4, it passes through a strainer 2 and a strainer pipe 3 to lubricate each engine part 5, and then returns to the oil tank 1 again, repeating the circulation cycle. ing. Note that 20 is a relief valve for bypassing oil when the pressure on the discharge side of the oil pump 4 increases excessively.

As mentioned above, when the engine is started at a low temperature, the viscosity of the oil is high, so the load on the oil pump 4 increases, the engine is not sufficiently lubricated, and it takes a considerable amount of time to reach a predetermined stable engine speed. was. In order to solve this problem, in the present invention, an oil flow rate restricting means such as a shut valve 6 is provided in the suction side (upstream side) pipe of the oil pump 4, and a A heater 7 is incorporated in the pipe line.

As shown in the figure, the shutter valve 6 is interlocked with a lever 12 connected to the output side of a diaphragm chamber 8, while the diaphragm chamber 8 is connected to a VSV valve 9, which will be described later, which is controlled by a controller 11.
The valve is operated by negative pressure supplied from a vacuum tank 10 under the control of the vacuum tank 10, and is configured to move the shut valve 6 via a lever 12 to shut off the pipe 3.

As shown in FIG. 2, the structure of the VSV valve 9 includes an E port 51 communicating with the diaphragm chamber 8;
It has three openings: an F port 52 that communicates with the vacuum tank 10 and a G port 53 that communicates with the atmosphere. In the illustrated state, the E port 51 communicates with the internal opening of the G port 53 inside the valve 9 through the gap at the lower end of the plunger 54, but the internal opening of the F port 52 communicates with the internal opening of the G port 53.
It is closed off by the upper end of the This makes the diaphragm chamber 8 equal to atmospheric pressure.

A coil 56 is provided surrounding the plunger 54, and when energized, the plunger 54 is connected to the spring 5.
It is configured to be pulled down against a force of 5.
Therefore, when the coil 56 is energized, the plunger 54
descends away from the internal opening of the F port 52, and the G
At the same time as closing the internal opening of the port 53, the internal opening of the F port 52 is opened and communicated with the E port 51. This makes the diaphragm chamber 8 equal to the negative pressure within the vacuum tank 10.

With the above configuration, the pressure within the diaphragm chamber 8 can be switched between negative pressure and atmospheric pressure depending on whether or not the coil 56 is energized.

Next, the operation of the system shown in FIG. 1 will be explained. When the temperature of the cooling water detected by the water temperature sensor S is below a predetermined temperature (for example, -20°C), when a key signal is input to the controller 11 by inserting the engine key, a command from the controller 11 is sent. As a result, the coil 56 of the VSV valve 9 is energized, a negative pressure is applied to the diaphragm chamber 8 by the mechanism described above, and the shut valve 6 shuts off the pipe 3. At the same time, the heater 7 is also energized and the oil near it is heated. During cranking by the starter,
Only a small amount of oil blocked by the shut valve 6 is efficiently heated and sucked into the oil pump 4 in a state where the viscosity is reduced, and the oil pump can be operated with less driving resistance. When the engine starts and the starter is stopped, the stop signal is input to the controller 11, and the VSV valve 9 and heater 8
energization is stopped, the shut valve 6 is opened,
Oil is sucked into the oil pump 4 from the oil tank 1 through the pipe 3 as usual, and begins to circulate to each part 5 of the engine. The relationship between these signals is shown in the diagram of FIG.

In addition, from the standpoint of safety, it is desirable that the heater 7 be made of a PTC element that has low electrical resistance at low temperatures and instantly raises the temperature, and as the temperature rises, the resistance value increases and the amount of current decreases. . Further, power for operating this system is supplied by a battery 13.

[Embodiment] FIG. 4 shows a system according to a second embodiment of the present invention. In this example as well, a heater and flow rate limiting means are provided in the pipe line just before the suction side of the oil pump, but in order to simplify the structure, the shut valve 6 as the flow rate limiting unit in the system shown in Fig. 1 is replaced. A metal mesh 16 is used. Other corresponding parts are designated by the same reference numerals as in FIG. This principle is basically the same as the former, and the viscosity of oil changes greatly depending on temperature, that is, at low temperatures, the viscosity is high and the resistance to passage through the metal mesh 16 is large, so the flow rate decreases. This method takes advantage of the fact that as the temperature rises, the viscosity gradually decreases, the passage resistance decreases, and the flow rate increases.

To explain this effect, when both a key signal and a water temperature signal below a predetermined temperature are input to the controller 11 at the same time, power from the battery 13 is applied to the heater 7 (preferably consisting of a PTC element), Raise the temperature of the oil nearby. When the starter starts, the oil whose viscosity has been reduced by heating is easily sucked into the oil pump 4 and circulates through the pipe with low driving resistance. Since the flow rate passing through the metal mesh 16 is limited while the oil temperature is low, it can be efficiently heated by the heater 7, and as the oil temperature rises, the passage resistance decreases. Therefore, the flow rate gradually increases and the desired lubrication effect can be achieved.

FIG. 5 shows a third embodiment of the system of the present invention. In this example, a metal mesh is used as the flow rate restricting means as in the case of the second embodiment, but the structure in combination with the heater has been further devised. That is, the metal mesh 26 is installed in the strainer pipe 3 on the suction side of the oil pump, and a bypass passage 14 equipped with a heater 7 (preferably a PTC element) is installed surrounding the metal mesh 26.

To explain the operation of this system, when a key signal and a water temperature signal lower than a predetermined temperature are simultaneously input to the controller 11 during startup, the heater 7
Power from the battery 13 is applied to the battery 13. When the starter starts, the oil has a high viscosity due to the low temperature, so it is difficult to pass through the metal mesh 26 in the pipe, and the oil mainly bypasses the bypass passage 14 and is heated by the heater 7. The heated oil is sucked into the oil pump 4. Therefore, at the time of starting the engine, oil whose viscosity has been reduced due to heating is circulated through the pipes, reducing the driving resistance of the oil pump and making it possible to start the engine smoothly. When the engine rotation becomes stable and the oil temperature rises, the resistance to passage through the metal mesh 26 decreases, so the amount of oil passing through the metal mesh 26 rather than through the bypass passage 14 increases, resulting in a steady state. becomes. At this point, power supply to the heater 7 is stopped.

According to the third embodiment, compared to the second embodiment, it is possible to prevent troubles due to oil shortage immediately after starting when the oil temperature is low, and the reliability of the system is improved.

〔Effect of the invention〕

As described in detail above, according to the present invention, the oil flow rate limiting means and the oil heating means are provided on the suction side of the oil pump of the oil circulation system for the internal combustion engine, and the oil flow rate limiting means and the oil heating means are provided on the suction side of the oil pump of the oil circulation system for the internal combustion engine, and the By activating the means, a small amount of oil is efficiently heated to lower its viscosity and then supplied to the oil pump, thereby reducing the driving resistance of the pump and making it possible to start the engine smoothly.
If a PTC element is used as a heating means, rapid heating is possible and overheating of the heater can be prevented, improving safety. Further, if a fixed metal mesh is used as the oil flow rate restricting means, the structure becomes simple and there is an advantage that the flow rate can be self-controlled in accordance with the oil temperature.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a typical oil circulation system of the present invention, Fig. 2 is a diagram showing the relationship of each signal in the system of Fig. 1, and Fig. 3 is a VSV valve used in the system of Fig. 1. FIG. 4 is a schematic diagram of a system according to a second embodiment of the present invention, and FIG. 5 is a schematic diagram of a system according to a third embodiment of the present invention. 1...Oil tank, 2...Strainer, 3...
...Strainer pipe, 4...Oil pump, 5...
... Engine parts, 6 ... Shut valve, 7 ... Heater, 8 ... Relief valve, 9 ... VSV valve, 1
0...Vacuum tank, 11...Controller, 12...Lever, 13...Battery, 14...Bypass passage, 16, 26...Metal mesh, 51...E port, 52...F port, 53... ...G port, 5
4... Plunger, 55... Spring, 56...
…coil.

Claims (1)

[Scope of Claims] 1. An internal combustion engine characterized in that, in a circulation system that supplies oil to the internal combustion engine, means for restricting the flow rate of oil and means for heating the oil are provided on the suction side of an oil pump. oil supply system. 2. The oil supply system for an internal combustion engine according to claim 1, wherein the oil heating means is provided between the oil flow rate limiting means and the oil pump. 3. The oil supply system for an internal combustion engine according to claim 1, wherein the oil heating means is provided in an oil circulation system in parallel with the oil flow rate limiting means. 4. The oil supply system for an internal combustion engine according to any one of claims 1 to 3, wherein the oil flow rate restricting means is variable. 5. The oil supply system for an internal combustion engine according to any one of claims 1 to 3, wherein the oil flow rate restricting means is of a fixed type. 6. The oil supply system for an internal combustion engine according to any one of claims 1 to 5, wherein the oil heating means is a PTC heater.