JPH0567770B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine with a supercharger, and more particularly to a control device for an internal combustion engine equipped with a supercharger that is driven by the engine and forcibly feeds pressurized air to the intake system of the engine. It is something.

As is well known, a supercharger is a positive displacement air pump that is driven by the engine through a gear train, chain, or V-belt, and as the rotational speed of the engine increases, the rotational speed of the supercharger also increases, causing an increase in the intake system. The supplied air flow rate increases. In this way, the rotation of the supercharger is determined only by the rotational speed of the engine, so when the accelerator opening, that is, the opening of the throttle valve, is small, even though the amount of intake air is being throttled. Regardless, the problem arises that excessive supercharging is performed, resulting in poor fuel efficiency and reduced durability of the supercharger.

In order to solve this problem, Japanese Patent Application Laid-Open No. 58-18518
A supercharging device for an internal combustion engine has been proposed as disclosed in the publication. That is, in this supercharging device, a control valve, that is, a bypass valve, is disposed in a bypass passage that communicates the suction side and the discharge side of the air pump.
In order to control supercharging operation when the engine is under low load,
The bypass valve is directly connected to the throttle valve drive system. In other words, the control valve is rotated via the damper and the link mechanism in conjunction with the rotation of the accelerator pedal. As described above, since the above-mentioned conventional device employs a mechanical connection means using a link system, structural play is likely to occur due to vibrations received from the engine or the influence of high heat, reducing the durability of each link, and furthermore, The large number of connected parts increases manufacturing costs and reduces operational reliability.

SUMMARY OF THE INVENTION In view of the problems of the conventional device described above, an object of the present invention is to provide a structure in which a bypass valve is actuated by a signal pressure generated by a change in the opening degree of a throttle valve.

The technical means taken in the present invention to achieve the above object includes a throttle valve disposed in the middle of an intake passage of an engine, and a supercharger that supplies pressurized air to the intake passage. In an internal combustion engine, there is a bypass passage that communicates the suction side and the discharge side of the supercharger, a bypass valve disposed in the middle of the bypass passage to control opening and closing of the bypass passage, a body, and a body that partitions the inside of the body. 1st room and 2nd room
A diaphragm valve that has a diaphragm that forms a chamber, a rod that is slidably disposed to open and close the bypass valve as the diaphragm moves, and a spring that is disposed in the first chamber and biases the diaphragm in the direction in which the bypass valve closes. The actuator, a port that opens into the intake passage within the stroke range of the throttle valve and detects pressure according to the opening position of the throttle valve, and a second chamber that is constantly communicated with the port and detected by the port. The second pressure is adjusted according to the throttle valve opening position.
The pressure on the downstream side of the passage leading into the chamber and the throttle valve is detected, and if the pressure on the downstream side is less than a predetermined value, negative pressure is introduced into the first chamber, and when the pressure on the downstream side is greater than the predetermined value. and a pressure control valve for introducing atmospheric pressure into the first chamber.

According to the above technical means, a diaphragm type valve actuator is adopted for driving the bypass valve, and the actuator is operated in response to a signal pressure corresponding to the opening position of the throttle valve detected by the port. Therefore, the above-mentioned problems of the link type conventional device can be solved.

In addition, a port was provided in the intake passage within the stroke range of the throttle valve, so
At low and medium load times, that is, when the throttle valve reaches the upstream side of the port, negative pressure is detected by the port, and the negative pressure is introduced into the second chamber of the valve actuator. On the other hand, negative pressure is detected by the pressure control valve, and the negative pressure is introduced into the first chamber. As a result, the bypass valve is fully closed by the biasing force of the spring, and supercharging is performed. In this way, supercharging is possible at low and medium loads, that is, when the throttle valve is half open.

Also, the pressure on the downstream side of the throttle valve is detected, and if the pressure on the downstream side is smaller than a predetermined value, the first
We have adopted a pressure control valve that introduces negative pressure into the chamber and introduces atmospheric pressure into the first chamber when the downstream pressure is above a predetermined value, so if the boost pressure becomes excessive, the throttle valve will be activated. The pressure on the downstream side becomes positive pressure, that is, a predetermined value or more, and atmospheric pressure is introduced into the first chamber by the pressure control valve. On the other hand, positive pressure is detected by the port, and the positive pressure is introduced into the second chamber via the passage. As a result, the bypass valve opens and reduces the boost pressure. in this way,
By employing the above-mentioned pressure control valve, the valve actuator has the function of a relief valve when the boost pressure becomes excessive, and there is no need to provide a separate relief valve.

Furthermore, the supercharging state (bypass valve is fully closed)
When the engine shifts to a deceleration state, the throttle valve is suddenly closed, so the pressure on the discharge side of the supercharger increases rapidly. At this time, positive pressure is generated on the upstream side of the throttle valve, and negative pressure is generated on the downstream side of the throttle valve. Positive pressure is then immediately introduced into the second chamber of the actuator through the port and passage, and negative pressure is immediately introduced into the first chamber of the actuator by the pressure control valve.
As a result, the pressure difference between the first chamber and the second chamber becomes significantly large, and the bypass valve immediately opens. Therefore, the pressurized air on the discharge side of the supercharger is immediately released to the suction side via the bypass passage, and the excess pressure on the discharge side of the supercharger is immediately reduced, driving the supercharger. The supercharger will no longer be damaged due to excessive pressure. Thereby, there is no problem even if the supercharger is driven all the time, so there is no need to provide a switching means such as an electromagnetic clutch for switching the supercharger between operation and non-operation, which is advantageous in terms of cost.

Hereinafter, an example embodying the present invention will be described.
The explanation will be based on the attached drawings.

A supercharger 10, that is, a supercharger shown in the drawings, is driven by an engine through a gear train, chain, or belt, and its suction side is connected to an air cleaner (not shown) through a passage 11, and its discharge side is connected to an air cleaner (not shown) through a passage 12. They each communicate with the intake system of the engine 13, that is, with a carburetor (intake passage) 15 having a throttle valve 14. A bypass valve 17 is attached to a bypass passage 16 that communicates the suction side passage 11 and the discharge side passage 12 of the supercharger 10, and the bypass valve 17 is driven by a valve actuator 30.
The flow rate of passing air is controlled by controlling the opening and closing of the valve. The body 31 of the valve actuator 30 is airtightly separated into a first chamber 33 and a second chamber 34 by a diaphragm 32, and the second chamber 34 has a port 35,
The passage 36 communicates with the carburetor port 18 which opens into the carburetor 15 within the stroke range of the throttle valve 14, while the first chamber 33 is connected to the port 37 and the pressure control valve 50 through the passage 38. Receives signal pressure from.
Retainers 39 and 40 are fixed to both sides of the center of the diaphragm 32, and a driving rod 41 connected to the retainers 39 and 40 moves the diaphragm 32.
The upper end of the drive rod 41 in the drawing is attached to the above-mentioned bypass valve 1.
It is connected to 7. That is, when the drive rod 41 moves upward in the figure, the bypass valve 17 closes the bypass passage 16, and the first chamber 33
The diaphragm 32 is constantly biased upward in the drawing by a spring 42 that is stretched.

On the other hand, the body 5 of the pressure control valve 50
The inside of 1 has a diaphragm 52 and a partition wall 53,
A first chamber 54, an atmospheric chamber 55, and a second chamber 56 are formed. 55 communicates with an atmospheric source such as an air cleaner (not shown) through a port 59, and is connected to the second chamber 5.
6 communicates with the first chamber 33 of the valve actuator 30 described above through a port 60 and a passage 38, and at the same time communicates with the intake manifold 19 described above through a port 61 and a passage 62. A retainer 6 is provided on both sides of the center of the diaphragm 52.
3 and 64 are fixed, and a rod 65 connected to the retainers 63 and 64 is displaced and operated together with the diaphragm 52, and as a result of this operation, a valve 66 connected to the rod 65 opens the atmospheric chamber 55 and the second chamber 56. It is configured to control communication with the atmospheric chamber 55.
The diaphragm 52 is biased to the right in the figure by a spring 67 disposed in the valve 66 .
is constantly biased toward its closed position.

The operation of the control device for an internal combustion engine with a supercharger having the above structure will now be described.

First, when the load on the engine 13 is small and the throttle valve 14 is located downstream (low opening side) from the carburetor port 18, negative pressure is generated in the intake manifold 19, and this negative pressure is transferred to the passage 5.
8 and port 57 to the first chamber 54, and via passage 62 and port 61 to the second chamber 56. Therefore, the diaphragm 52 is displaced to the right in the figure and the valve 66 is held in the closed position, so that the port 6 of the pressure control valve 50 is closed.
Negative pressure is generated at 0. As a result, negative pressure is supplied to the first chamber 33 from the port 60 via the passage 38. On the other hand, since substantially atmospheric pressure acts on the carburetor port 18, atmospheric pressure is supplied to the second chamber 34 of the valve actuator 30. Therefore, the drive rod 41 moves downward in the figure against the biasing force of the spring 42, so the bypass valve 17 opens the bypass passage 16, and the supercharging action is no longer performed. In this way, a supercharging effect at low engine loads is prevented.

Next, when the throttle valve 14 opens and is held at a position beyond the carburetor port 18, negative pressure also acts on the port 18, so the negative pressure is applied to the passage 3.
6 to the second chamber 34 of the actuator 30, and both the first chamber 33 and the second chamber 34 have the same pressure. As a result, the drive rod 41 is moved upward by the spring 42, and the bypass valve 17 closes the bypass passage 16, so that supercharging is performed. When the supercharging pressure increases and exceeds the set pressure, that is, the set pressure of the pressure control valve 50, the pressure in the first chamber 54 of the control valve 50 moves the valve 66 to the left in the figure, and the atmospheric chamber 55
Since the first chamber 56 and the first chamber 56 communicate with each other, atmospheric pressure is supplied to the first chamber 33 of the actuator 30 through the port 60 and the passage 60 . At this time, pressure is generated in the carburetor port 18 due to supercharging, so
The drive rod 41 of the actuator 30 moves downward against the urging force of the spring 42, so that the bypass valve 17 opens the bypass passage 16 and lowers the supercharging pressure. In this way, the valve actuator 30 has a function as a relief valve when the boost pressure reaches the maximum.

Also, when the engine decelerates, the throttle valve 1
4 is suddenly closed, positive pressure is applied to the carburetor port 18 and intake manifold 19
A negative pressure is generated in the actuator 30, and a negative pressure and a positive pressure are rapidly supplied to the first chamber 33 and the second chamber 34 of the actuator 30, respectively, so that the bypass valve rapidly opens and the supercharging action is stopped.

[Brief explanation of the drawing]

The drawing is a sectional view showing an embodiment of a control device for a supercharged internal combustion engine according to the present invention. 10...Supercharger, 11...Suction side passage, 12...Discharge side passage, 13...Engine,
14... Throttle valve, 15... Carburetor (intake passage), 16... Bypass passage, 17... Bypass valve, 18... Carburetor port (port), 20... Intake manifold, 30...
... Valve actuator, 32 ... Diaphragm, 50 ... Pressure control valve, 52 ...
diaphragm.

Claims (1)

[Scope of Claims] 1. In an internal combustion engine comprising a throttle valve disposed in the middle of an intake passage of the engine and a supercharger that supplies pressurized air to the intake passage, the supercharging a bypass passage that communicates the suction side and the discharge side of the machine; a bypass valve disposed in the middle of the bypass passage to control opening and closing of the bypass passage; a body; and a first chamber and a first chamber that partition the inside of the body. a diaphragm that forms a second chamber; a rod that is slidably disposed to open and close the bypass valve as the diaphragm is displaced; and a rod that is disposed within the first chamber and moves the diaphragm in the direction in which the bypass valve closes. a diaphragm valve actuator having a biasing spring; a port that opens into the intake passage within a stroke range of the throttle valve and detects pressure according to the opening position of the throttle valve; a passage that constantly communicates the second chamber with the port and introduces pressure into the second chamber according to the opening position of the throttle valve detected by the port; a pressure control valve that detects the pressure and introduces negative pressure into the first chamber when the pressure on the downstream side is smaller than a predetermined value, and introduces atmospheric pressure into the first chamber when the pressure on the downstream side is equal to or higher than the predetermined value; A control device for a supercharged internal combustion engine, characterized by comprising: