JPH0326266Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention is applicable to an exhaust turbo supercharger driven by exhaust gas in the intake system, or a mechanical type driven by power transmission from an internal combustion engine. The present invention relates to a device for controlling the boost pressure of an internal combustion engine equipped with a supercharger such as a supercharger.

[Conventional technology]

Generally, in this type of supercharged internal combustion engine, if the supercharging pressure to the internal combustion engine becomes higher than a certain set value, problems such as frequent knocking will occur in the internal combustion engine. .

Therefore, conventionally, as described in JP-A No. 50-87227, etc., a part of the intake air compressed by the supercharger was placed between the discharge side and the suction side of the supercharger. A blow passage that returns to the upstream side of the supercharger is connected, and the blow passage is provided with a regulating valve that opens when the supercharging pressure to the internal combustion engine becomes high, so that the supercharging pressure to the internal combustion engine reaches a certain level. When the set value is exceeded, the regulating valve opens and the excess air is recycled to the suction side of the supercharger via the blow passage, thereby controlling the supercharging pressure to the internal combustion engine so as not to exceed the set value. I have to.

[The problem that the idea attempts to solve]

In this way, when controlling the supercharging pressure, recycling the excess air from the regulating valve to the suction side of the supercharger via the blow passage increases the temperature of the supercharging air. This has the advantage of promoting fuel vaporization when the temperature of the internal combustion engine is low, preventing the occurrence of icing, and improving drivability during cold operation until the internal combustion engine warms up.

However, on the other hand, when the temperature of the internal combustion engine is high (that is, when the internal combustion engine is warmed up), the temperature of the supercharged air becomes higher due to the above recycling, and the supercharged air to the internal combustion engine increases. There is a problem in that the filling efficiency of the engine and, as a result, the output of the engine decreases.

The present invention aims to solve the above-mentioned problem when the surplus air released from the regulating valve is recycled to the suction side of the supercharger.

[Means to solve the problem]

To achieve this objective, the present invention provides a supercharger in the intake passage leading from the air cleaner to the internal combustion engine, and between the discharge side and suction side of the supercharger, the intake air compressed by the supercharger is A supercharged internal combustion type comprising a blow passage whose part returns to the upstream side of the supercharger, and a regulating valve that opens when the supercharging pressure to the internal combustion engine increases. In the engine, a discharge passage to the atmosphere is connected to the blow passage at a location downstream of the regulating valve, and a connection portion of the discharge passage to the blow passage is connected to excess air from the regulating valve. The structure includes a switching valve that allows the flow to flow into the blow passage when the temperature of the internal combustion engine is low, and to the discharge passage when the temperature of the internal combustion engine is high.

[Functions and effects of the idea]

With this configuration, surplus air from the regulating valve is recycled to the suction side of the supercharger via the blow passage when the temperature of the internal combustion engine is low, and this recycling reduces the amount of supercharging air to the internal combustion engine. Since the temperature can be raised rapidly, fuel vaporization can be promoted when the temperature is low, and icing can be prevented from occurring. On the other hand, when the temperature of the internal combustion engine is high, excess air from the regulating valve is released from the discharge passage. Since the supercharged air is not recycled to the suction side of the supercharger, it is possible to avoid an increase in the temperature of the supercharged air due to recycling.

Therefore, according to the present invention, it is possible to improve drivability during cold operation until the internal combustion engine warms up, and it is also possible to improve the charging efficiency after the internal combustion engine warms up, and as a result, the output of the internal combustion engine can be improved. .

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates an internal combustion engine equipped with an intake manifold 2 and an exhaust manifold 3, and reference numeral 4 indicates a machine rotationally driven by the internal combustion engine 1. In the intake passage 5 connecting the discharge side of the supercharger 4 and the intake manifold 2, there is a surge tank 6 for eliminating pulsation and a carburetor 7 with a throttle valve 8. A surge tank 6 is provided upstream of the carburetor, an air cleaner 9 is connected to the suction side of the supercharger 4 via a suction passage 10, and the exhaust manifold 3
An exhaust passage 11 is connected to the atmosphere.

Reference numeral 12 indicates a valve box for a regulating valve connected to the surge tank 6, which is a part of the intake passage from the supercharger 4 to the carburetor 7. The valve box 12 is connected to the suction side of the supercharger 4 through a blow passage 14, such as the clean side of the air cleaner 9 or the suction passage 10. Furthermore, inside this valve box 12,
a valve body 15 that abuts the valve seat opening 13; and the valve body 1.
5 and a spring 16 for pressing the valve seat opening 13.
The valve body 15 opens against the spring 16 by the boost pressure when the boost pressure in the surge tank 6 exceeds a certain value above atmospheric pressure, and when the valve body 17 opens, By releasing excess air,
This is to control the boost pressure so that it does not exceed a certain value above the atmospheric pressure.

A regulating valve 17 is provided in the blow passage 14.
A discharge passage 18 whose one end communicates with the atmosphere via a silencer 19 is connected to a more downstream part, and the surplus discharged from the regulating valve 17 is connected to the connection part of the discharge passage 18 to the blow passage 14. Air blow passage 1
A pressure-operated switching valve 20 is provided for switching between the case where the water is allowed to flow into the discharge passage 18 and the case where the water is allowed to flow into the discharge passage 18.

This pressure-operated switching valve 20 is connected to the blow passage 1
A spring 21 is provided to close the discharge passage 18 and hold the discharge passage 18 open. When supercharging pressure acts on the pressure chamber 22, the discharge passage 18 is closed and the blow passage 14 is
A supercharging pressure transmission passage 23 that is configured to switch to open and introduce supercharging pressure downstream of the supercharger 4 into the pressure chamber 22 has a pressure related to the temperature of the internal combustion engine 1. When the temperature is low, supercharging pressure is introduced into the pressure chamber 22, and when the temperature is high, the temperature sensing valve is configured to cut off the introduction of supercharging pressure into the pressure chamber 22 and at the same time open the pressure chamber 22 to the atmosphere. 2
4 will be provided.

In this configuration, when the temperature of the internal combustion engine 1 is low, that is, when the internal combustion engine 1 is not sufficiently warmed up, the switching valve 20 is activated by the operation of the temperature sensing valve 24.
The supercharging pressure acts on the pressure chamber 22 at the switching valve 2.
0 closes the discharge passage 18 and opens the blow passage 14, the excess air released from the regulating valve 17 flows into the blow passage 14 and is recycled to the suction side of the supercharger 4. , the temperature of the supercharged air can be rapidly raised.

When the temperature of the internal combustion engine 1 is high, that is, when the internal combustion engine 1 warms up to a predetermined temperature, the pressure chamber 22 in the switching valve 20 is opened to the atmosphere by the operation of the temperature sensing valve 24. Since the spring 21 switches the blow passage 14 to close the discharge passage 18 and open the discharge passage 18, the excess air released from the regulating valve 17 is not recycled to the suction side of the supercharger 4, but flows from the discharge passage 18. This prevents the supercharged air from rising in temperature by being released into the atmosphere.

Note that by connecting the discharge passage 18 to the exhaust passage 11 as shown by the two-dot chain line in the drawing,
Excess air from the regulating valve 17 may be released to the exhaust system, and in the above embodiment, a mechanical supercharger 4 rotationally driven by the internal combustion engine 1 is used as the supercharger. However, it goes without saying that other superchargers such as an exhaust turbo supercharger may be used in place of this mechanical supercharger.

[Brief explanation of drawings]

The drawings are diagrams showing embodiments of the present invention. 1...Internal combustion engine, 2...Intake manifold, 3
...exhaust manifold, 4...supercharger, 5...intake passage, 6...surge tank, 7...carburizer, 8
...Throttle valve, 9...Air cleaner, 14...
...Blow passage, 17...Adjustment valve, 18...Discharge passage, 20...Switching valve, 23...Supercharging pressure transmission passage,
24...Temperature sensing valve.

Claims (1)

[Scope of utility model registration request] A supercharger is installed in the intake passage leading from the air cleaner to the internal combustion engine, and a part of the intake air compressed by the supercharger is transferred between the discharge side and the intake side of the supercharger to the upstream side of the supercharger. In a supercharged internal combustion engine, the blow passage is connected to a regulating valve configured to open when the supercharging pressure to the internal combustion engine increases, A discharge passage to the atmosphere is connected to a portion downstream of the regulating valve, and a connection portion of the discharge passage to the blow passage is connected to the blow passage for directing excess air from the regulating valve to the blow passage when the temperature of the internal combustion engine is low. 1. A supercharging pressure control device for a supercharging internal combustion engine, characterized in that a switching valve is provided to allow the fluid to flow to the discharge passage when the temperature of the internal combustion engine is high.