JPH0478820B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a supercharged engine equipped with an exhaust turbo supercharger, and particularly to an engine equipped with a supercharger equipped with an exhaust turbo supercharger. It is about improvement.

(Prior art) In general, in an exhaust turbo supercharger installed in a supercharged engine, a rotating shaft that rotationally connects a turbine wheel and a compressor impeller is used to absorb heat from the exhaust gas that drives the turbine wheel. In order to prevent seizing due to frictional heat, etc., a large amount of oil is forcibly supplied to the bearing of the rotating shaft by an oil pump driven by the engine.
The rotating shaft is cooled while being lubricated.

However, on the other hand, when the engine is suddenly stopped immediately after high-speed, high-load operation, the oil supply is also stopped, so the oil remaining in the minute clearance of the bearing becomes carbonized by the heat of the exhaust gas. The rotating shaft became seized, and as a result, there was a risk that the supercharger would become inoperable when the engine was restarted.

Therefore, conventionally, as disclosed in Japanese Utility Model Application Publication No. 54-21708, etc., a cooling water passage for supplying engine cooling water to the exhaust turbo supercharger has been provided, and the engine stops suddenly after high-speed and high-load operation. Sometimes, the cooling water in the cooling water passage is evaporated by exhaust gas heat, and the supercharger is cooled by the heat of vaporization.
It has been proposed to prevent carbonization of oil by guiding air bubbles generated by evaporation upward to generate natural convection of cooling water and to continue cooling by the heat of vaporization.

However, in this proposal, engine cooling water is constantly supplied to the supercharger while the engine is running, so when the engine is operating at high speed and high load, the amount of cooling water flowing to the radiator is insufficient, causing the engine cooling water to drain. There was a problem in that the cooling water was not sufficiently cooled by the radiator and the temperature of the cooling water rose, resulting in engine overheating.

(Object of the Invention) The present invention has been made in view of the above points, and its purpose is to appropriately set the conditions for supplying the engine cooling water to the exhaust turbo supercharger. To prevent engine overheating without impairing cooling performance for a feeder.

(Structure of the invention) In order to achieve the above object, the structure of the present invention is as follows.
In a supercharged engine including an exhaust turbo supercharger and a cooling water passage supplying engine cooling water and an oil passage supplying oil to the exhaust turbo supercharger, the temperature of the engine cooling water is a predetermined value. A cooling water control valve is provided that reduces or stops the supply of cooling water to the cooling water passage when the temperature rises above the level above.

As a result, when the engine cooling water temperature rises above a predetermined temperature while the engine is operating, the supply of cooling water to the exhaust turbo supercharger is suppressed or stopped to ensure the amount of cooling water to the radiator and cool the engine. In addition, the exhaust turbo supercharger is mainly cooled by oil, and when the engine is stopped rapidly, the exhaust turbo supercharger is cooled by the natural convection of the engine cooling water.

(Effects of the Invention) Therefore, according to the present invention, when the temperature of engine cooling water rises above a predetermined value, the supply of cooling water to the exhaust turbo supercharger is suppressed or stopped to cool the engine. In addition, since the exhaust turbo supercharger is cooled by oil, it is possible to prevent engine overheating without impairing the cooling performance of the exhaust turbo supercharger. It is possible to improve the driving stability of the vehicle.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 schematically shows the overall configuration of an embodiment of the present invention, in which 1 is an engine, 2 is a radiator connected to the engine 1 by main cooling water passages 3 and 4, and 5 is a radiator connected to the engine 1. The water pump 5 circulates cooling water between the engine 1 and the radiator 2, and the water pump 5 circulates cooling water between the engine 1 and the radiator 2.
A cooling system is configured to guide and cool the air.

In addition, the main cooling water passage 3 through which the cooling water flows from the engine 1 to the radiator 2 is provided with a main cooling water passage 3 at its upstream end (connection part with the engine 1) when the temperature of the engine cooling water is below a predetermined value. A thermostat 6 for closing the cooling water passage 3 is provided.

In addition, in the engine 1, the main cooling water passage 3
The upstream end of a bypass passage 7 is connected to the vicinity of the upstream end of the bypass passage 7, and the downstream end of the bypass passage 7 is connected to the main cooling water passage 4 immediately upstream of the water pump 5. When the engine 1 is cold, the thermostat 6
By stopping the supply of engine cooling water to the radiator 2 and circulating the cooling water through the bypass passage 7, warm-up of the engine 1 is promoted.

On the other hand, 8 is an exhaust turbo supercharger for supercharging intake air to the engine 1, and the exhaust turbo supercharger 8 supercharges the exhaust gas of the engine 1, as shown in enlarged detail in FIG. The turbine housing 9 includes a turbine housing 9 that forms part of an exhaust passage for discharging gas, a bearing housing 10, and a compressor housing 11 that forms part of an intake passage that supplies intake air to the engine 1. has an exhaust inlet 9a and an exhaust outlet 9b open therein, and a turbine wheel 12 inside.
is rotatably supported. Further, the compressor housing 11 has an intake inlet 11a and an intake outlet 11b opened, and
A compressor impeller 13 is rotatably supported in the interior thereof. The turbine wheel 12 and the compressed impeller 13 are mounted in bearings 14 and 1 within the bearing housing 10.
4, and are rotatably connected to each other by a rotary shaft 15 rotatably supported through the exhaust gas inlet 9a, passing through the turbine housing 9 from the exhaust inlet 9a to the exhaust outlet 9.
The gas pressure of the exhaust gas flowing to b rotates the turbine wheel 12 and the compressor impeller 13 driven by the turbine wheel 12, and the rotation of the compressor impeller 13 causes intake air to flow into the compressor housing 11 from the intake inlet 11a. After being sucked in and compressed, it is configured to be supplied to the engine 1 from the intake air outlet 11b.

Further, an oil passage 16 for supplying oil to the bearings 14, 14 is formed in the bearing housing 10 of the exhaust turbo supercharger 8, and the upstream end of the oil passage 16 is driven by the engine 1. The downstream end is connected to an oil pump (not shown) and the downstream end is connected to a reservoir (not shown), so that the oil pumped from the oil pump flows into the oil passage 16 and is forcibly supplied to the bearings 14, 14. I have to.

A cooling water passage 17 is formed in the bearing housing 10 on the turbine housing 9 side so as to surround the rotating shaft 15, and a cooling water inlet of the cooling water passage 17 supplies cooling water as shown in FIG. It is connected to the engine 1 near the upstream end of the main cooling water passage 3 via a passage 18, while the cooling water outlet is connected to the main cooling water passage 3 immediately downstream of the thermostat 6 via a cooling water recirculation passage 19. A portion of the engine cooling water is passed through the cooling water supply passage 18 to the cooling water passage 1 of the exhaust turbo supercharger 8.
7.

Furthermore, in the middle of the cooling water supply passage 18,
A temperature-sensitive cooling water control valve 20 is provided to control the supply of cooling water to the cooling water passage 17 of the exhaust turbo supercharger 8 according to the temperature of the engine cooling water. As shown in enlarged detail in FIG. 3, the cooling water control valve 20 includes a valve case 21 that is fixed to a communicating wall of the cooling water supply passage 18 so as to close it, and has a valve opening 21a. A first opening and closing valve opening 21a of the valve case 21.
Valve body 22, the first valve body 22 and valve case 21
a valve spring 23 that is compressed between the valve spring 23 and biases the first valve body 22 in the valve-closing direction;
2 and has a slidable needle 24a that engages with the valve case 21, and is filled with wax that expands due to temperature rise, and expands so as to push out the needle 24a by the expansion of the wax. A cylinder 24 that opens the first valve body 22 against the biasing force of a valve spring 23, and a cylinder 24 that is attached to the tip of the cylinder 24 (the end opposite to the needle 24a), A second valve body 25 is provided that throttles the throttle opening 18a formed in the cooling water supply passage 18 during expansion. Therefore, when the temperature of the engine coolant rises to a predetermined value (for example, 80 to 90 degrees Celsius) higher than the valve opening temperature of the thermostat 6, the cylinder 24 of the coolant control valve 20 expands and the second valve opens. When the valve body 25 throttles the throttle opening 18a of the cooling water supply passage 18, the exhaust turbo supercharger 8
The cooling water passage 17 is configured to reduce the supply of cooling water to the cooling water passage 17.

Next, the operation of the above embodiment will be explained.
During operation of the engine 1, oil is supplied to the oil passage 16 of the exhaust turbo supercharger 8 by the operation of the oil pump driven by the engine 1, and by supplying oil to the oil passage 16, the turbine wheel 12 and the Bearings 14, 14 that support the rotating shaft 15 that connects the twin impeller 13
is cooled while being forcibly lubricated, and the lubrication and cooling by this oil prevents the rotating shaft 15 from seizing.

Further, when the temperature of the engine cooling water is lower than a predetermined temperature, the thermostat 6 is closed, the cooling water control valve 20 is closed by closing its first valve body 22, and the engine cooling water is diverted to the bypass passage 7.
warm-up of the engine 1 is promoted. After this, the temperature of the cooling water rises and the engine 1
When warm-up is completed, the thermostat 6 is opened and cooling water is circulated between the engine 1 and the radiator 2, and the cooling water in the radiator 2 cools the engine 1. Simultaneously with the opening of the thermostat 6, the cooling water control valve 20 is opened by opening its first valve body 22, and a portion of the engine cooling water circulating between the engine 1 and the radiator 2 is released. The cooling water is supplied to the cooling water passage 17 of the exhaust turbo supercharger 8 through the cooling water supply passage 18, thereby cooling the exhaust turbo supercharger 8 supplementary to the cooling by the oil.

When the temperature of the engine cooling water further increases due to high-speed, high-load operation of the engine 1 and reaches a predetermined value or more, the second valve body 25 of the cooling water control valve 20 opens the throttle opening of the cooling water supply passage 18. 18a
By narrowing down the passage area of the cooling water supply passage 18, the passage area of the cooling water supply passage 18 is reduced, and the supply of engine cooling water to the cooling water passage 17 of the exhaust turbo supercharger 8 is suppressed.

Therefore, the engine cooling water mainly circulates between the engine 1 and the radiator 2, and almost all of the cooling water cooled by the radiator 2 is supplied to the engine 1. Capacity can be ensured well and overheating can be prevented.

At that time, by suppressing the supply of engine cooling water to the cooling water passage 17 of the supercharger 8, the supercharger 8 becomes difficult to be cooled by the engine cooling water. As oil from the oil pump is supplied to the supercharger 8,
There is no shortage of cooling performance for the supercharger 8.

Further, when the engine 1 is abruptly stopped from a high-speed, high-load operating state, the exhaust turbo supercharger 8 is no longer cooled by oil due to the oil pump stopping operation, but instead, the exhaust turbo supercharger 8 is no longer cooled by oil. The engine cooling water in the cooling water passage 17 evaporates due to the heat of the high-temperature exhaust gas, absorbing the heat of vaporization from the surroundings, and the supercharger 8 is cooled by the heat of vaporization, and the bubbles generated by the evaporation flow upward. Since the convection of the cooling water is promoted and the cooling of the supercharger 8 is continued by the heat of vaporization, the cooling performance for the supercharger 8 can be ensured, and the rotation of the bearings 14, 14 of the supercharger 8 can be ensured. It is possible to prevent oil remaining in the clearance with the shaft 15 from carbonizing, thereby preventing seizure of the rotating shaft 15. As a result, the supercharger 8 can be operated smoothly when the engine 1 is restarted.

In the above embodiment, when the engine coolant temperature rises to a predetermined temperature or higher, the coolant control valve 20 throttles the coolant supply passage 18 and the exhaust turbo supercharger 8
The supply of engine cooling water to the cooling water passage 17 is suppressed, but when the temperature of the engine cooling water rises above a predetermined temperature, the cooling water supply passage 18 is closed by the cooling water control valve 20 to stop the engine cooling. The supply of water to the exhaust turbo supercharger 8 may be stopped, and the same effects as in the above embodiment can be achieved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall schematic diagram, FIG. 2 is an enlarged vertical sectional view of a supercharger, and FIG. 3 is an enlarged longitudinal sectional view of a cooling water control valve. 1...Engine, 2...Radiator, 6...Thermostat, 8...Exhaust turbo supercharger, 12...
...Turbine wheel, 13...Complex impeller, 14...Bearing, 15...Rotating shaft, 1
6...Oil passage, 17...Cooling water passage, 18...
...Cooling water supply passage, 18a...Aperture opening, 20
...Cooling water control valve.

Claims (1)

[Claims] 1. In a supercharged engine that is equipped with an exhaust turbo supercharger and has a cooling water passage that supplies engine cooling water to the exhaust turbo supercharger and an oil passage that supplies oil, the temperature of the engine cooling water is A supercharged engine characterized by being provided with a cooling water control valve that reduces or stops supply of cooling water to the cooling water passage when the temperature rises above a predetermined value.