JPH06257455A - Preventing mechanism for lubricating oil from flowing out into intake manifold from turbocharger - Google Patents

Abstract

PURPOSE:To provide a means for keeping an oil pressure in the center housing of a turbocharger at a suitable value, so as to prevent oil in a low-speed region of an engine from leaking into a compressor chamber and flowing out to an intake manifold. CONSTITUTION:Two rows of lubricating oil circuits are formed in parallel between the oil discharging port 8 of a turbocharger 10 and the lubricating oil tank 20 of an engine, and a first row is provided with only a lubricating oil pipeline 35, while a second row is provided with an oil discharging lubricating oil pump 37 in a lubricating oil pipeline 36. And lubricating oil flow to both rows is always allowed to flow into the first row. When the engine speed is less than the specified one, the flow is switched to the second row by an electromagnetic directional control valve 33. Thereby the oil discharging lubricating oil pump 37 is driven so as to discharge oil in the turbocharger 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication device for a turbocharger, and more particularly to a mechanism for preventing oil from leaking into an intake manifold in a low speed region of the turbocharger.

[0002]

2. Description of the Related Art In a conventional turbocharger, exhaust gas G from an exhaust manifold (not shown) flows into a turbine chamber 4 as shown in FIG.
Rotates, and accordingly, the compressor 2 also rotates via the shaft 3, and the intake air A is forcibly sent to the intake manifold (not shown) to perform supercharging. The turbine 1 and the compressor 2 are supported by a center housing (oil drain chamber) 6, and the center housing 6 and the turbine chamber 4 are supported.
And the compressor chamber 5 are sealed by ring-shaped oil seals 9 and 11, respectively.

In the lubrication device of the turbocharger 10, the oil pumped from the lubricating oil tank (oil pan) of the engine by the oil pump is supplied from the oil filling port 7 of the turbocharger 10 to a bearing (not shown) inside the center housing 6. After being lubricated, the oil is dropped from the oil discharge port 8 by its own weight and returned to the oil pan. Japanese Utility Model Laid-Open No. 53-37809 discloses an oil seal 9 in the conventional turbocharger lubricating device.
An oil (lubricating oil) pipe is provided between the oil discharge port 8 and the oil pan of the turbocharger 10 in order to prevent the supercharging performance from being deteriorated by the oil leaking from the turbine chamber 4 and the compressor chamber 5 from 11. Proposals have been made in which a lubricating oil pump (oil pump) is provided between the pipes by making them communicate with each other.

[0004]

In the conventional structure in which the oil is collected into the oil pan by dropping the oil from the oil discharge port 8 by its own weight, the oil supplied to the center housing 6 is If the amount becomes larger than the discharge amount and the pressure in the center housing 6 rises too much, the oil accumulated in the center housing 6 may leak from the oil seal to the turbine chamber 4 or the compressor chamber 5.

For this reason, in order to prevent this, the actual exploitation 53
In Japanese Patent Laid-Open No. 37809, it is proposed to provide an oil pump in the oil discharge pipe line. In this case, however, the oil pump needs oil in the center housing 6 because it is always operating. Due to the above suction, a problem such as seizure may occur in the bearing portion of the turbocharger due to lack of oil, and further, a problem may occur in which air is sucked from the turbine chamber 4 and the compressor chamber 5 to cause cavitation. .

In the conventional turbocharger, the pressure inside the center housing 6 becomes higher than the back pressure of the impeller of the compressor 2 in the low engine speed range (600 to 800 rpm), and particularly in this range. Since the pressure inside the housing 6 is higher than that in the compressor chamber 5, oil will pass through the oil seal 11.
As described above, the center housing 6 depends on the engine speed.
Since the balance between the internal pressure and the internal pressure of the compressor chamber 5 is different, it is necessary to control the internal pressure of the center housing 6 within an appropriate value range so as not to become excessive or excessive during engine rotation. .

In view of the above circumstances, the present invention provides means for maintaining the hydraulic pressure in the center housing at an appropriate value so that the oil does not leak into the compressor chamber, particularly in the low speed rotation range, depending on the engine speed. The purpose is to do.

[0008]

In order to achieve the above object, in the present invention, lubricating oil is fed from the lubricating oil circuit of the engine to the oil filling port of the turbocharger via the check valve. In a turbocharger lubrication device, there are two series of lubricating oil circuits connected to the oil discharge port of the turbocharger, the first series is only a lubricating oil pipeline, and the second series is a lubricating oil pipeline for lubricating oil. There is provided a lubricating oil outflow prevention mechanism for an intake manifold of a turbocharger comprising an oil pump and a directional control valve for switching a flow of the lubricating oil to the both series according to an operating state of an engine.

The directional control valve is an electromagnetic type,
When the engine speed is equal to or lower than a predetermined speed, the flow path may be switched to the second series lubricating oil pipe line and the lubricating oil pump for discharging oil may be operated.

[0010]

Operation: Normally, the lubricating oil circuit from the oil discharge port of the turbocharger to the lubricating oil tank uses the directional control valve for the first
The oil in the turbocharger is brought into series, drops by its own weight and is returned to the oil pan. When the operating state of the engine becomes a predetermined state, for example, a predetermined number of revolutions or less, the electromagnetically operated directional control valve operates to switch the lubricating oil circuit to the second series, and the lubricating oil pump for discharging oil operates to operate the turbocharger. Forcibly drain the oil in the charger. As a result, the oil pressure of the lubricating oil in the turbocharger does not drop, does not leak through the oil seal to the turbine chamber or compressor chamber, and the oil flows out into the intake manifold through the compressor chamber especially in the low speed rotation range. Is prevented.

[0011]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic layout diagram of a means for preventing oil from flowing out to the intake manifold according to this embodiment. In the figure, the turbocharger 10 has the same structure as that of FIG. 3 described above, and the common portions are denoted by the same reference numerals. 1
Is a turbine, 2 is a compressor, 3 is a shaft, 4 is a turbine chamber, 5 is a compressor chamber, 6 is a center housing, 7 is an oil supply port, 8 is an oil discharge port, 9 and 11 are oil seals, G is an exhaust gas, A is intake air.

As shown in the drawing, the path for supplying and recovering the lubricating oil (oil) to the turbocharger 10 is such that the oil sucked up by the first oil pump 22 from the oil pan 20 through the oil pipe 21 passes through the filter 23. After that, oil is sent to each lubricated portion 24 of the engine, and a part of the oil is sent to the oil filling port 7 of the turbocharger 10 through the check valve 25 and the oil pipe (oil feeding pipe) 26. The oil that has finished lubrication of each bearing portion in the center housing 6 of the turbocharger exits from the oil discharge port 8, passes through the oil pipe (oil feed pipe) 34, and passes through the direction control valve 33 to the oil pan 2
Recovered within 0.

The direction control valve 33 is a valve that changes the direction of the flow of oil discharged from the turbocharger 10 by an electromagnetic method, and this control is performed in the following procedure. That is, oil is normally communicated from the oil feed pipe 34 to the oil pan 20 via the direction control valve 33, the oil pipe line (oil feed pipe) 35, and the sensor 28 to the electronic control unit (ECU) 3.
According to the information of the engine speed input to 0, when this speed is equal to or lower than a predetermined low speed (600 to 800 rpm), the changeover switch 32 is actuated by the signal from the ECU 30 to move the electromagnetic directional control valve 33. The oil supply pipe 34 is disconnected from the oil supply pipe 35, communicates with the oil supply pipe 36, and communicates with a lubricating oil pump (also referred to as a second oil pump) 37 for oil discharge arranged in the oil supply pipe 36. The center housing 6 of the turbocharger 10 is operated by the operation of the pump.
The oil inside is sucked and discharged into the oil pan 20.

With the above operation, when the engine is rotating at a low speed, the oil pressure in the center housing 6 is higher than the pressure in the compressor chamber 5, so that the oil leaks into the compressor chamber 5 through the oil seal 11 and the intake air is taken. Oil is prevented from spilling into the manifold. FIG. 2 shows an example of the relationship between the pressure inside the compressor chamber 5 and the center housing (oil drain chamber) 6 and the engine speed. In the figure, when the engine speed is about 750 rpm or less, the pressure in the center housing 6 is higher than the pressure in the compressor chamber 5, so that the lubricating oil leaks through the oil seal 11.

In order to eliminate the above-mentioned condition, in this embodiment, the operation of switching the electromagnetic directional control valve 33 by the rotation speed sensor 28 and the changeover switch 32 so that the discharged oil passes through the second oil pump 37 at about 800 rpm. Thus, at the engine speed of 800 rpm or more, the conventional normal oil dropping method is used, and at 800 rpm or less, the second oil pump 37 is forcibly sucked and collected in the oil pan.

As described above, the leakage of lubricating oil from the center housing, which has occurred in the low engine speed range of the conventional engine, to the compressor chamber is eliminated. Further, the present invention is not limited to the above embodiment, and for example, the lubricating oil pump 37 for discharging oil may not be newly provided and may also serve as the first oil pump 22. In this case, one end of the oil feed pipe 36 is connected to the first oil pump 2
In addition to communicating with the negative pressure side of 2, the drive control of the second oil pump 37 based on the engine speed becomes unnecessary. The point is that negative pressure should act on the second series of lubricating oil pipelines.

[0017]

The following effects can be obtained by implementing the present invention. That is, leakage of lubricating oil from the center housing of the turbocharger to the compressor chamber, which has conventionally occurred in the low speed rotation range of the engine, is eliminated, and wasteful consumption of oil is prevented.

[Brief description of drawings]

FIG. 1 is a schematic layout view of an oil outflow prevention means from a turbocharger to an intake manifold according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a pressure in a compressor chamber and a center housing of a turbocharger and an engine speed.

FIG. 3 is a schematic view showing a cross section of a turbocharger in the related art.

[Explanation of symbols]

 4 ... Turbine chamber 5 ... Compressor chamber 6 ... Center housing (oil drain chamber) 7 ... Oil supply port 8 ... Oil discharge port 9, 11 ... Oil seal 10 ... Turbocharger 20 ... Lubricating oil tank (oil pan) 22 ... First Oil pump 25 ... Check valve 28 ... Engine speed sensor 32 ... Changeover switch 33 ... Direction control valve (electromagnetic system) 34, 35, 36 ... Lubricating oil pipe (oil feeding pipe) 37 ... Lubricating oil pump for oil discharge (second) Oil pump) 40 ... Lubricating oil circuit

Claims (2)

[Claims] 1. A turbocharger lubrication device in which lubricating oil is sent from a lubricating oil circuit of an engine to an oil supply port of a turbocharger, and the lubricating oil circuit connected to the oil discharge port of the turbocharger has two series. , The first series communicates with the lubricating oil tank through the lubricating oil line,
The second series is provided with a lubricating oil pump for discharging oil in the lubricating oil pipeline, and a directional control valve for switching the flow of the lubricating oil to the two series according to the operating state of the engine. Lubricant oil outflow prevention mechanism to the intake manifold of the charger. 2. The directional control valve uses an electromagnetic method to switch the flow path to the second series lubricating oil pipeline when the engine speed is equal to or lower than a predetermined rotational speed to operate the lubricating oil pump for discharging oil. A lubricating oil outflow prevention mechanism for an intake manifold of a turbocharger according to claim 1, wherein the mechanism is configured as described above.