JPS6233069Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine equipped with an exhaust turbo supercharger that uses exhaust gas to rotate an exhaust turbine and uses the power to drive a compressor.

BACKGROUND ART Recently, internal combustion engines equipped with exhaust turbo superchargers have been put into practical use in automobiles and the like in order to improve engine output without increasing engine displacement.

In an internal combustion engine equipped with this exhaust turbocharger, the exhaust energy of the exhaust gas is effectively utilized, this exhaust gas is used to turn an exhaust turbine, and this power is used to drive a compressor to pre-pressurize the intake air (or air-fuel mixture) supplied to the engine, thereby increasing the charging efficiency of the intake air (or air-fuel mixture) supplied to the engine and improving the output of the engine.

However, in an internal combustion engine equipped with an exhaust turbocharger, due to the inertia of the exhaust turbocharger itself or friction in the friction part, the rotational speed of the compressor increases until the exhaust gas increases the rotational speed of the exhaust turbine. There is a time delay before the compressor speed rises, and the time it takes for the compressor rotation speed to rise during acceleration (several seconds) Operating performance (acceleration performance)
There was a problem that the value decreased.

Therefore, in order to improve the performance during acceleration, an internal combustion engine has been proposed in which the exhaust bypass valve or supercharging relief valve is closed during acceleration, as disclosed in, for example, Japanese Utility Model Application Publication No. 54-37703. There is.
However, in such an internal combustion engine, although the supercharging pressure can be increased from normal, this does not fundamentally solve the above-mentioned time delay when the engine speed increases. As a means to solve this time delay, for example, it is possible to reduce the diameter of the exhaust turbine and compressor to lower the inertial mass and improve the start-up of the increase in the rotational speed of the exhaust turbine and compressor. In this case, a new problem arises in that the supercharging pressure becomes excessive when the engine rotates at high speeds, resulting in a significant decrease in the durability of the engine itself.

The present invention was made in view of the above facts, and its purpose is to temporarily reduce the load applied to the compressor by opening the bypass passage that bypasses the compressor during acceleration, and thereby,
Improves the rise in the compressor rotation speed,
An object of the present invention is to provide an internal combustion engine equipped with an exhaust turbo supercharger that can significantly improve acceleration performance by shortening the time required to increase the rotational speed of a compressor.

According to the present invention, a suction passage, a compressor for an exhaust turbo supercharger disposed in the suction passage, and a throttle valve disposed in the suction passage downstream of a portion where the compressor is disposed; a bypass passage arranged to bypass the compressor; a passage opening/closing valve for opening and closing the bypass passage; a diaphragm device for operating the passage opening/closing valve;
one end of the bypass passage is connected to a portion of the suction passage upstream of the installation portion of the compressor, and the other end is connected to a portion of the suction passage upstream of the installation portion of the compressor and the throttle valve. The diaphragm device has a first chamber and a second chamber separated by a diaphragm. The chambers are communicated via an orifice, and the first chamber is further communicated with a portion of the suction passage downstream of the location where the throttle valve is disposed via a first communication passage. An internal combustion engine with features is provided.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific example of an internal combustion engine equipped with a turbocharger constructed in accordance with the present invention will be described in detail with reference to the accompanying drawings.

1 illustrating a first embodiment of an internal combustion engine having an exhaust turbocharger constructed in accordance with the present invention;
In the figure, an internal combustion engine 2 includes an intake pipe 8 in which an intake passage 6 for sucking air from an air cleaner 4 is formed, and an exhaust passage 10 for discharging exhaust gas to the outside.
The exhaust pipe 12 is connected to the exhaust pipe 12 in which the exhaust pipe 12 is formed. This engine 2 is equipped with an exhaust turbo supercharger 14, an exhaust turbine 16 of the exhaust turbo supercharger 14 is arranged in the exhaust passage 10, and a compressor 18 directly connected to the exhaust turbine 16 is connected to the intake passage 6. It is arranged.

The above-mentioned configuration is an internal combustion engine equipped with a known exhaust turbocharger, and when the exhaust turbine 16 of the exhaust turbocharger 14 is rotated by the exhaust gas of the engine 2, the compressor 18 is is rotated, and the intake air supplied to the engine 2 is pressurized by the compressor 18 and supplied to a cylinder (not shown).

In the present invention, a bypass passage is provided in the intake passage of an internal combustion engine by bypassing the compressor, and a passage opening/closing valve is provided in this bypass passage.

As shown in FIG. 1, a throttle valve 22 that opens and closes the suction passage 6 in conjunction with the action of the accelerator pedal 20 is disposed at a downstream side of the suction passage 6 from where the compressor 18 is disposed. Ori,
Furthermore, a bypass passage 38 is provided, one end of which opens at a location upstream from the location where the compressor 18 is disposed, and the other end of which opens at a location between the location where the compressor 18 and the throttle valve 22 are disposed. It is connected to the suction passage 6, and a passage opening/closing valve 40 is disposed in this bypass passage 38. This passage opening/closing valve 4
0 is opened and closed by a diaphragm device 42 that detects negative pressure downstream of the throttle valve 22 and operates.

A diaphragm 46 is attached to this diaphragm device 42, and a support member 44 is fixed to this diaphragm 46. diaphragm 4
One end of the passage opening/closing valve 40 is fixed to a support member 44 integral with the passage opening/closing valve 6, and the passage opening/closing valve 40 is operated by operating the diaphragm 46. The diaphragm device 42 is partitioned into a first chamber 48 and a second chamber 50 by a diaphragm 46.
The first chamber 48 communicates with a portion of the suction passage 6 downstream of the throttle valve 22 via a first communication passage. The first chamber 48 and the second chamber 50 are connected to an orifice 54 formed through the diaphragm 46 and the support member 44.
communicated by. Inside the second chamber 50,
Spring member 5 that holds the passage opening/closing valve 40 in a closed state
6 is installed.

Next, to explain the effects of the internal combustion engine equipped with the above-mentioned exhaust turbo supercharger, when the engine 2 is in a low load steady state (throttle valve 22 is at a low opening), the negative pressure downstream of the throttle valve 22 is reduced. is connected to the diaphragm device 42 through the first communication path 52.
acts on the first chamber 48 of the orifice 5
4 to the second chamber 50, and the pressure in the first chamber 48 and the pressure in the second chamber 50 are kept the same. To this end, the passage opening/closing valve 40 is moved to the right in FIG. 1 by the elastic biasing force of the spring member 56 and is held in the closed state. Therefore, intake air from the air cleaner 4 is supplied to the engine 2 via the compressor 18.

Next, when the throttle valve 22 is opened from this state to shift to an acceleration state, the throttle valve 2
2, the negative pressure downstream of the throttle valve 22 temporarily decreases, and this decreased negative pressure
The first of the diaphragm device 42 via the communication path 52 of
is transmitted to chamber 48. And this first chamber 4
8 increases (the negative pressure in the first chamber 48 decreases), the pressure temporarily held in the second chamber 50 (the negative pressure downstream of the throttle valve 22 at a low opening of the throttle valve 22) increases. , the diaphragm 46 is moved to the left in FIG. 1 against the force of the spring member 56, and therefore the passage opening/closing valve 40
is moved to the left and becomes open. Thus, most of the intake air is sent to the compressor 18.
On the other hand, the compressor 18 has a smaller load on itself (the load required to feed intake air to the engine 2), and the exhaust gas is supplied to the exhaust turbine 16. Together with this, the rotational speed is suddenly increased.

When a predetermined period of time has elapsed after the transition to the above-mentioned acceleration state, the pressure in the first chamber 48 and the pressure in the second chamber 50 of the diaphragm device 42 become equal due to the action of the orifice 54, and the spring member The elastic biasing force of 56 causes the diaphragm 46 to move to the right in FIG.
0 is moved to the right and becomes blocked. In this way, the supply of intake air through the bypass passage 38 is stopped, and intake air precompressed by the compressor 18, which is maintained at a high rotational speed when the bypass passage 38 is opened, is supplied to the engine 2.

During deceleration, the negative pressure downstream of the throttle valve 22 increases, and this negative pressure passes through the first communication path 52 and the pressure in the first chamber 48 becomes lower than the pressure in the second chamber 50. Therefore, the passage opening/closing valve 40 is maintained in a closed state, and intake air is not supplied from the bypass passage 38.

As described above, in the first specific example, a bypass passage for bypassing the compressor is provided in the suction passage, and a passage opening/closing valve is provided in this bypass passage, so that during acceleration, the first chamber 48 of the diaphragm device 42 is closed. When the negative pressure decreases from the second chamber 50, this passage opening/closing valve is temporarily activated to open the bypass passage, so that at the start of acceleration, most of the intake air flows through the bypass passage to the engine. During this period, the load applied to the compressor itself decreases, causing its rotational speed to rise rapidly. Next, after a predetermined period of time has elapsed, the pressures in the first chamber 48 and the second chamber 50 become substantially equal due to the action of the orifice 54, thereby closing this bypass passage and maintaining the high rotational state. Since intake air pre-pressurized by the compressor is now supplied to the engine, the compressor rotation speed can be increased from low rotation to high rotation in a shorter time than before, resulting in a significant acceleration state. It can be made better and better.

In the first specific example, the size of the orifice that communicates the first chamber and the second chamber of the diaphragm device is appropriately selected, and this bypass passage is opened when the rotational speed of the compressor increases to a certain extent after the start of acceleration. If it is not blocked, the negative pressure downstream of the throttle valve will continue to decrease (the boost pressure by the compressor will increase) as the compressor rotational speed increases after acceleration starts, and the pressure in the first chamber and the second chamber will continue to decrease. A situation arises in which the pressure difference between the pressure in the chamber of A portion of the intake air pre-pressurized by the compressor that has increased to high rotational speed is returned to the intake passage upstream of the compressor via this bypass passage, which may cause a problem in which breathing occurs during acceleration. .

In order to reliably eliminate the above-mentioned sluggish development,
As shown in FIG. 2 or 3, when the boost pressure downstream of the throttle valve exceeds a predetermined value, this boost pressure is applied to the second chamber of the diaphragm device to cause the elastic bias of the spring member. The diaphragm may be returned to its original state by force, and the passage opening/closing valve may be moved to the closed state.

The following description will be made based on a second specific example illustrated in FIG. Hereinafter, the same members as those in the first specific example will be given the same reference numbers.

The first communication passage 52 further includes a second communication passage 58 that communicates with the second chamber 50 of the diaphragm device 42.
are connected to each other (therefore, the second chamber 5 is communicated via the second communication passage 58 and the first communication passage 52 to a portion of the suction passage 6 downstream of the location where the throttle valve 22 is disposed). An on-off valve 62 operated by a diaphragm device 60 is disposed in the second communication path 58. When the on-off valve 62 is in the open state, the boost pressure downstream of the throttle valve 22 is transferred to the first communicating path 52 and the second communicating path 5.
8 to the second chamber 50.

The diaphragm device 60 is partitioned into a third chamber 68 and a fourth chamber 70 by a diaphragm 64, and an on-off valve 62 is fixed to the surface of the diaphragm 64 on the third chamber 68 side.

A second passage 58 is connected to the third chamber 68, and an opening 7 communicating with the atmosphere is connected to the fourth chamber 70.
2 is provided. Also, within the fourth chamber 70 is a spring member 6 that holds the on-off valve 62 in a closed state.
6 is installed.

The rest of the configuration is substantially the same as the first specific example shown in FIG. 1, so the explanation thereof will be omitted.

In the second specific example of the above-described configuration, when the throttle valve 22 is opened and the engine shifts to an acceleration state, the reduced negative pressure downstream of the throttle valve 22 is transferred to the 1 room 4
The diaphragm 46 is actuated by the pressure (negative pressure) maintained in the second chamber 50, the passage opening/closing valve 40 is opened, and intake air is supplied through the bypass passage 38. Ru.

While the bypass passage 38 is open and intake air is being supplied, the rotational speed of the compressor 18 increases rapidly, and when pre-pressurized intake air begins to be supplied through the compressor 18, the turbocharging downstream of the throttle valve 22 is activated. pressure increases, and this supercharging pressure becomes the first
and the opening/closing valve 62 of the diaphragm device 60 in the second communication path 58. Then, when this boost pressure exceeds a predetermined value,
The action of this supercharging pressure causes the diaphragm 64 to operate against the force of the spring member 66, and the supercharging pressure downstream of the throttle valve 22 is transferred to the second diaphragm device 42 via the second communication path 58. is transmitted to chamber 50.

Thus, as the boost pressure increases, the first chamber 4
Although the difference between the pressure inside the valve 8 and the pressure inside the second chamber 50 was maintained approximately constant, this on-off valve 6
2, the pressure in the first chamber 48 and the pressure in the second chamber 50 become substantially the same, and the passage opening/closing valve 40 is actuated by the action of the spring member 56 and enters the closed state. Intake air precompressed by the compressor 18 is supplied to the engine 2.

As described above, in the second specific example, when the boost pressure downstream of the throttle valve exceeds a predetermined value, the on-off valve of the second communication passage is opened and the second
In order to transmit this supercharging pressure to the first chamber and to make the pressure in the first chamber substantially the same as the pressure in the second chamber and to close the passage opening/closing valve, a compressor applies prepressurization during acceleration. This prevents the intake air from being returned to the intake passage upstream of the compressor via the bypass passage, thereby preventing the boost pressure of the intake air supplied to the engine from temporarily decreasing. This makes it possible to prevent the phenomenon of breathing during acceleration.

In the second specific example described above, an on-off valve operated by the diaphragm device is disposed in the second communication path that communicates the second chamber of the diaphragm device with the downstream side of the throttle valve. A solenoid valve operated by a signal from a pressure sensor may be provided to do so.

In FIG. 3, an electromagnetic on-off valve 74 is provided as an on-off valve in the second communication passage 58, and a pressure detector 76 is provided in the suction passage 6 downstream of the throttle valve 22. The signal from this pressure detector 76 is passed through a pressure-to-voltage converter 78 to a comparator 8.
0, and if the output voltage from the pressure-voltage converter 78 is higher than a predetermined voltage (voltage set by the variable resistor R), a signal is output from the comparator 80 and transmitted to the base of the transistor 82. Ru. As a result, the transistor 82 becomes conductive, the electromagnetic on-off valve 74 operates and becomes open, and the pressure downstream of the throttle valve 22 is transmitted to the second chamber 50 via the second communication path 58.

The effect of the third specific example described above is that the suction passage 6
When the boost pressure downstream of the throttle valve 22 exceeds a predetermined value, the signal from the pressure detector 76 becomes
The second specific example shown in FIG. 2 is the same as the one shown in FIG. 2, except that the signal is transmitted to the comparator 80 via the voltage converter 78, and the output signal from the comparator 80 is transmitted to the transistor 82, so that the electromagnetic on-off valve 74 is in the open state. Since it is substantially the same as , its explanation will be omitted.

As described above, in the third specific example as well, when the boost pressure downstream of the throttle valve exceeds a predetermined value, the electromagnetic on-off valve is operated to open the second communication path, and the inside of the first chamber is In order to make the pressure substantially the same as the pressure in the second chamber and close the passage opening/closing valve, the intake air pre-pressurized by the compressor during acceleration passes through the bypass passage and enters the intake passage upstream of the compressor. It is not reversed, and therefore, it is possible to prevent the supercharging pressure of the intake air supplied to the engine from decreasing temporarily.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating one embodiment of an internal combustion engine equipped with an exhaust turbocharger constructed in accordance with the present invention. FIG. 2 is a schematic diagram illustrating a second embodiment of an internal combustion engine with an exhaust turbocharger constructed in accordance with the present invention. FIG. 3 is a schematic diagram illustrating a third embodiment of an internal combustion engine with an exhaust turbocharger constructed in accordance with the present invention. 2... Engine, 6... Intake passage, 10... Exhaust passage, 14... Exhaust turbo supercharger, 16... Exhaust turbine, 18... Compressor, 38... Bypass passage, 40... Passage opening/closing valve, 42...Diaphragm device, 46...Diaphragm, 48...First
chamber, 50... second chamber, 54... orifice.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A suction passage, a compressor for an exhaust turbo supercharger disposed in the suction passage, and a throttle disposed in the suction passage downstream of the location where the compressor is disposed. comprising a valve, a bypass passage arranged to bypass the compressor, a passage opening/closing valve for opening and closing the bypass passage, and a diaphragm device for operating the passage opening/closing valve, one end of the bypass passage. is connected to a part of the suction passage upstream from the installation part of the compressor, and the other end is connected to a part of the suction passage between the installation part of the compressor and the throttle valve. The diaphragm device has a first chamber and a second chamber separated by a diaphragm, and the first chamber and the second chamber communicate with each other via an orifice, The internal combustion engine is further characterized in that the first chamber is in communication with a portion of the suction passage downstream of the placement portion of the throttle valve via a first communication passage. 2. The second chamber communicates with a portion of the suction passage downstream of the throttle valve via a second communication passage in which an on-off valve is provided, and the on-off valve is connected to the intake passage. The internal combustion engine according to claim 1, wherein the second communication passage is opened when the boost pressure on the downstream side of the throttle valve exceeds a predetermined value.