JPS633131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an internal combustion engine equipped with a supercharger driven by exhaust gas, that is, an exhaust turbo supercharger, in which the boost pressure is adjusted in response to acceleration operation in the internal combustion engine. The invention relates to a device that is controlled by

In an internal combustion engine equipped with an exhaust turbo supercharger, in order to control the boost pressure so that it does not exceed a certain value, a blower compressor is installed in the exhaust bypass passage provided for the exhaust turbine in the exhaust turbo supercharger. A wastegate valve related to the boost pressure on the downstream side is provided, and when the boost pressure reaches a preset normal setting boost pressure, the wastegate valve is opened and a part of the exhaust gas is bypassed. It is well known, for example, from Japanese Patent Laid-Open No. 52-59211, to prevent the boost pressure from increasing further.

However, with an exhaust turbo supercharger, when the internal combustion engine accelerates, the rise in rotation is delayed due to the inertia of the exhaust turbine and blower compressor, and the rise in supercharging pressure is slow, and the supercharging pressure is controlled as described above. For,
The disadvantage is that sufficient acceleration performance cannot be obtained.

Therefore, Japanese Utility Model Application Publication No. 54-37703 as a prior art discloses that when the accelerator pedal is rapidly depressed when accelerating the internal combustion engine, the waste gate valve is held in a closed state to reduce the boost pressure from the waste gate valve. It is proposed to improve acceleration performance by increasing the boost pressure above the normally set boost pressure using a gate valve.

However, this prior art, in other words, as long as the accelerator pedal is depressed rapidly.
Unless the sudden depression of the accelerator pedal is stopped, the wastegate valve will remain closed and the boost pressure will rise sharply to a greater extent than the normally set boost pressure.
This sudden increase in supercharging pressure cannot be predicted at all and may lead to extreme supercharging, so there is a great risk of damaging the exhaust turbo supercharger, etc. If the intake depression of the accelerator pedal is stopped early, the supercharging pressure will not rise above the normally set supercharging pressure, so sufficient acceleration performance will not be obtained.

The present invention solves this problem and increases the boost pressure above the normally set boost pressure for a certain period of time when accelerating the internal combustion engine, thereby improving acceleration performance without compromising safety. Another invention aims to further improve acceleration performance.

In order to achieve this object, the first invention provides a pressure-operated exhaust bypass passage that communicates the upstream side and the downstream side of the exhaust turbine, and opens the bypass passage when the supercharging pressure exceeds a set pressure. In an exhaust turbocharged internal combustion engine provided with a wastegate valve of the type shown in FIG. A first pressure transmission passage is provided which communicates through a delay means for transmitting the pressure, and the pressure chamber of the wastegate valve is further connected to a supercharging passage downstream of the blower compressor in parallel with the delay means in the first pressure transmission passage. A second pressure transmission passage is provided, which is communicated via a pressure on-off valve that opens when the boost pressure becomes higher than the set pressure.

Further, in addition to the first invention, a second invention has a configuration in which a second delay means is provided in the second pressure transmission passage on the downstream side of the pressure opening/closing valve.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the first invention,
In this figure, reference numeral 1 denotes a three-cylinder internal combustion engine having an intake manifold 2 and an exhaust manifold 3;
Reference numeral 4 indicates an exhaust turbo supercharger that directly connects an exhaust turbine 5 and a blower compressor 6, and a supercharging passage that connects the discharge side of the blower compressor 6 in the exhaust turbo supercharger 4 to the intake manifold 2. 7
is provided with a surge tank 8 for eliminating pulsation and a carburetor 10 with a throttle valve 9, an air cleaner 11 is connected to the suction side of the blower compressor 6, and an exhaust turbine in the exhaust turbo supercharger 4 is connected to the suction side of the blower compressor 6. The exhaust manifold 3 is connected to the inlet side of the exhaust turbine 5 via an exhaust passage 13, and the exhaust pipe 14 to the atmosphere is connected to the outlet side of the exhaust turbine 5.

Reference numeral 15 indicates an exhaust bypass passage provided between the exhaust passage 13 and the exhaust pipe 14, bypassing the exhaust turbine 5, and a pressure-operated waste gate valve 17 is provided in the exhaust bypass passage 15. The wastegate valve 17 is provided with a spring 19 that normally biases the valve body 18 in the closing direction, while the blower compressor 6 and the vaporizer 1 are installed in the pressure chamber 20 of the wastegate valve 17.
By introducing the supercharging pressure in the supercharging passage 7 or surge tank 8 between the , the valve body 18 resists its spring 19.
It's starting to open.

A throttle orifice 22 and a check valve 23 that opens only in the direction toward the supercharging passage 7 are arranged in parallel in the pressure transmission passage 16 to the 17 pressure chambers 20 of the waste gate valve. 1 delay means 24 is provided, while the first pressure transmission passage 16 includes:
The supercharging passage 7 bypasses the first delay means 24.
and a second pressure transmission passage 2 that communicates with the pressure chamber 20.
5 is provided in this second pressure transmission passage 25,
A pressure on/off valve 27 is provided. This pressure on/off valve 27
connects the port 28 to the spring 30 in the atmosphere communication chamber 29.
A spring 30 closes the port 28 when the boost pressure reaches an acceleration set boost pressure (P1) that is appropriately higher than the normal set boost pressure (Po).
is configured to open against the

In this configuration, the supercharging pressure in the supercharging passage 7 or the surge tank 8 is the normal set supercharging pressure (Po).
When the pressure decreases to below, the check valve 23 in the delay means 24 in the pressure transmission passage 16 is opened, so that the drop in boost pressure is transmitted to the pressure chamber 20 of the wastegate valve 17 without any time delay, and the While immediately closing the body 18, the supercharging passage 7 or the surge tank 8
The boost pressure in the pressure chamber 20 is increased only through the throttle orifice 22 by closing the check valve 23 in the delay means 24 in the pressure transmission passage 16.
However, during normal acceleration when the throttle valve 9 is opened slowly, the increase in the engine speed and, by extension, the increase in the rotation speed of the exhaust turbocharger 4 is gradual, and therefore the supercharging pressure increases. The rise is also slow and is not subject to the delay regulation of the orifice 22, so the increase in supercharging pressure is directly transmitted to the pressure chamber 20, and the supercharging pressure becomes the normally set supercharging pressure (Po) at the wastegate valve 17. At this point, the valve body 1 of the wastegate valve 17
8 opens and bypasses part of the exhaust gas to the exhaust turbine 5, so the boost pressure is controlled so as not to exceed the normal boost pressure (Po),
The supercharging pressure characteristic with respect to the rotational speed at this time becomes a curve A shown by a solid line in FIG.

However, when the throttle valve 9 is suddenly opened and the throttle valve 9 is suddenly opened for sudden acceleration, the engine speed rises quickly, and the speed of the exhaust turbo supercharger 4 also rises quickly, and the supercharging pressure rises rapidly. Pressure chamber 20 with rapid increase in boost pressure
The transmission of the boost pressure to the engine is delayed appropriately due to the regulation at the orifice 22, and during this time the valve body 18 of the wastegate valve is held in the closed state, so that the boost pressure to the engine is equal to the normally set boost pressure (Po). When the pressure in the pressure chamber 20 rises to the normally set supercharging pressure (Po) after the delay time caused by the orifice 22 has elapsed, the waste gate valve 1
The valve body 18 of No. 7 opens and the exhaust gas is sent to the exhaust turbine 4.
Since the boost pressure is bypassed, the boost pressure is controlled to return to the normal set boost pressure (Po).

In other words, the supercharging characteristics when the engine suddenly accelerates are as follows:
The result is curve B shown by the dashed line in Figure 2, and since the boost pressure to the engine exceeds the normally set boost pressure (Po) for a certain period of time when the engine is rapidly accelerating, the engine output will decrease during this period. This increases acceleration performance.

However, the increase in boost pressure in this case depends on the acceleration state of the internal combustion engine, and depending on the acceleration state of the internal combustion engine, the boost pressure may unexpectedly increase significantly during the time regulated by the first delay means 24. In some cases, this can become an extremely dangerous situation.

In contrast, the present invention is provided with the second pressure transmission passage 25 equipped with the pressure opening/closing valve 27 as described above, so that the first delay means 24 allows supercharging to occur during the regulation time. Acceleration set boost pressure (P1) whose pressure is appropriately higher than the normal set boost pressure (Po)
At this time, the pressure on/off valve 27 opens, cancels the delay action by the first delay means 24, and opens the valve body 18 of the wastegate valve 17, so the supercharging pressure characteristics at this time are as shown in FIG. The maximum supercharging pressure during sudden acceleration can be controlled so as not to exceed the acceleration setting supercharging pressure (P1), without compromising the safety system. Acceleration performance can be improved.

Further, FIG. 3 shows an embodiment of the second invention, which is a pressure opening/closing valve 27 provided in the second pressure transmission passage 25 in the embodiment of FIG. 1.
A second delay means 34 in which an auxiliary throttle orifice 32 and a check valve 33 which opens only in the direction toward the pressure opening/closing valve 27 are arranged side by side is provided on the downstream side. Note that the second delay means 34 may include only the auxiliary throttle orifice 32.

With this configuration, even when the boost pressure reaches the acceleration setting boost pressure (P1) and the pressure opening/closing valve 27 opens during sudden acceleration of the engine, the boost pressure is immediately transmitted to the pressure chamber 20. The wastegate valve 17 remains closed until the pressure in the pressure chamber 20 rises to the normally set supercharging pressure (Po). Therefore, the boost pressure will gradually exceed the acceleration set boost pressure (P1) and then slowly return to the normal set boost pressure (Po).
The boost pressure characteristics at that time will be as shown by the dotted line D in Figure 2, and the boost pressure will change during sudden acceleration.
Since the boost pressure can be maintained near the acceleration setting boost pressure (P1) for an appropriate period of time, acceleration performance can be further improved without impairing the safety of the internal combustion engine.

In addition, in the embodiment, the second pressure transmission passage 25 is connected to the first pressure transmission passage 16,
Although the case is shown in which the first delay means 24 is provided so as to be bypassed, this second pressure transmission passage 25
As shown by the dotted lines in Figures 1 and 3,
Various forms can be adopted as long as they bypass the first delay means 24, such as connecting the supercharging passage 7 and the pressure chamber 20 completely separately from the pressure transmission passage 16 of the first delay means 24.

As described above, the first invention has the structure described in claim 1, and when the engine accelerates, the valve body of the waste gate valve is
The delay means keeps it closed for a predetermined period of time to raise the boost pressure above the normally set boost pressure, while the pressure on/off valve regulates the boost pressure during acceleration so that it does not exceed a certain value. Therefore, the acceleration performance of an internal combustion engine can be improved without compromising safety.

Further, a second invention is such that, in addition to the first invention, a second delay means is provided in the second pressure transmission passage on the downstream side of the pressure on-off valve. This invention has the effect of further promoting acceleration performance, which is the effect of the invention.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, FIG. 1 is a diagram showing the first embodiment, FIG. 2 is a diagram showing supercharging pressure characteristics with respect to rotational speed, and FIG. 3 is a diagram showing the second embodiment. It is. 1... Internal combustion engine, 4... Exhaust turbo supercharger, 5
...Exhaust turbine, 6...Blower compressor, 7...
...Supercharging passage, 15...Exhaust bypass passage, 17...
...Wastegate valve, 20...Pressure chamber, 16...
First pressure transmission passage, 24...first delay means, 2
5...Second pressure transmission passage, 27...Pressure opening/closing valve, 34...Second delay means.

Claims (1)

[Claims] 1. A pressure-operated wastegate valve that is provided with an exhaust bypass passage that communicates the upstream and downstream sides of the exhaust turbine, and that opens when boost pressure exceeds a set pressure. In an exhaust turbocharged internal combustion engine, the pressure chamber is connected between the supercharging passage downstream of the blower compressor and the pressure chamber in the wastegate valve through a delay means that delays and transmits pressure only in the direction to the pressure chamber. furthermore, in parallel with the delay means in the first pressure transmission passage, a supercharging passage downstream of the blower compressor and a pressure chamber of the wastegate valve are connected to each other at a supercharging pressure. A supercharging pressure control device for an exhaust turbocharged internal combustion engine, characterized in that a second pressure transmission passage is provided which communicates through a pressure on/off valve that opens when the pressure becomes higher than the set pressure. 2. An exhaust turbo comprising an exhaust bypass passage that communicates the upstream and downstream sides of the exhaust turbine, and a pressure-operated wastegate valve that opens when boost pressure exceeds a set pressure in the bypass passage. In the supercharged internal combustion engine, the supercharging passage downstream of the blower compressor and the pressure chamber in the wastegate valve are communicated via a first delay means that delays and transmits pressure only in the direction to the pressure chamber. 1 pressure transmission passage is provided, and the supercharging passage downstream of the blower compressor and the pressure chamber of the wastegate valve are connected in parallel with the first delay means in the first pressure transmission passage so that the supercharging pressure is The second valve is connected via a pressure on/off valve that opens when the pressure is higher than the set pressure.
supercharging pressure control in an exhaust turbocharged internal combustion engine, characterized in that a pressure transmission passage is provided, and a second delay means is provided in the second pressure transmission passage downstream of the pressure on-off valve. Device.