JPH03225030A - Combined type supercharger of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent oversupercharging by transmitting supercharge intake pressure at an operation time of a mechanical type supercharger while composed pressure with atmospheric pressure at a non-operation time, to a supercharge intake pressure transmitting passage to a pressure chamber actuating a waste gate valve of a combined type supercharger. CONSTITUTION:At an internal combustion engine 1, an exhaust turbo supercharger 5 and a mechanical type supercharger 8 are provided. A bypass passage 11 which has a waste gate valve 13 normally closed is provided between an exhaust passage 9 and a exhaust pipe 10. A pressure chamber 12b which operates the waste gate valve 13 is connected to a supercharging passage 21 through a pressure transmitting passage 25. When the engine 1 is under high speed and low load, the mechanical type supercharger 8 is shut. A solenoid switching valve 29 is opened so as to activate combined pressure which is formed of supercharge intake pressure and atmospheric pressure at the pressure chamber 12b. Since the waste gate valve 13 is opened so as to prevent oversupercharging, knocking is not generated.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides supercharging for an internal combustion engine using an exhaust turbo supercharger driven by exhaust gas in the internal combustion engine, and an exhaust turbo supercharger driven by power transmission from the internal combustion engine. This invention relates to a so-called composite type supercharging device that uses both a mechanical supercharger and a mechanical supercharger in series.

[Conventional technology]

In general, a composite supercharging device that is used in series with both an exhaust turbo supercharger and a mechanical supercharger for supercharging an internal combustion engine is well known, and as a prior art, Japanese Patent Laid-Open No. 62
Publication No. 87618 discloses a mechanical supercharger that is installed in the intake path from the air cleaner to the internal combustion engine and is driven by power transmitted from the internal combustion engine only in the low speed range below the medium speed range, and a mechanical supercharger that is driven by exhaust gas. and an exhaust turbo supercharger arranged in series, and an on-off valve that is closed when the mechanical supercharger is driven to rotate is provided in an intake bypass passage that bypasses the mechanical supercharger. In the composite supercharging device, a waste gate is provided in the exhaust bypass passage that bypasses the exhaust turbine in the exhaust turbo supercharger and opens when the supercharging intake pressure for the internal combustion engine becomes higher than a predetermined set value. By providing a valve, when controlling the supercharging intake pressure so that it does not exceed the predetermined value, transmitting information to the wastegate valve when the mechanical supercharger is operating in a low speed rotation range. It is proposed to prevent the rotation speed of the exhaust turbo supercharger from decreasing in a low speed rotation range by lowering the supercharging intake pressure and preventing the waste gate valve from opening.

[Problem to be solved by the invention]

However, in this type of composite supercharging device, in the low speed range, both the exhaust turbo supercharger and the mechanical supercharger are driven, so that the intake air to the internal combustion engine is transferred to the exhaust turbo supercharger. Since the internal combustion engine is compressed by both engine and mechanical supercharging, the supercharging intake pressure for the internal combustion engine is the sum of the compression pressure in the exhaust turbo supercharger and the compression pressure in the mechanical supercharger. .

Therefore, the method of closing the waste gate valve in the exhaust bypass passage that bypasses the exhaust turbo supercharger in the low speed rotation range where the mechanical supercharger is operating, as in the prior art described above, As the rotational speed of the internal combustion engine increases, the intake pressure greatly increases beyond the predetermined set value, and then, as the rotational speed increases, the mechanical supercharger stops operating and the wastegate valve closes. The supercharging intake pressure for the internal combustion engine fluctuates greatly as the rotational speed of the internal combustion engine increases, such as when the internal combustion engine opens, the supercharging intake pressure rapidly decreases to the predetermined set value.
The output fluctuations in the internal combustion engine are large, resulting in a significant drop in drivability.Moreover, when the mechanical supercharger is in operation, the supercharging intake pressure to the internal combustion engine greatly exceeds the predetermined set value, causing supercharging. This caused problems such as knocking. ' The present invention solves this problem, namely, in the low speed range where both the exhaust turbo supercharger and the mechanical supercharger operate, the supercharging intake pressure for the internal combustion engine increases significantly beyond a predetermined set value. The object of the present invention is to provide a composite supercharging device that can reliably reduce the

[Means to solve the problem]

In order to achieve this object, the present invention provides a mechanical supercharger that is installed in the intake path from the air cleaner to the internal combustion engine and is driven by power transmission from the internal combustion engine only in the low speed range below the medium speed range, and an exhaust An exhaust turbo supercharger driven by gas is disposed in series, and an intake bypass passage that bypasses the mechanical supercharger is closed when the mechanical supercharger is driven to rotate. While the valve is provided, a pressure-operated wastegate valve is provided in the exhaust bypass passage that bypasses the exhaust turbine in the exhaust turbocharger, and is configured to open when boosting intake pressure for the internal combustion engine acts on the pressure chamber. In the composite supercharging device, when the mechanical supercharger is not in operation, a composite pressure of the supercharging intake pressure and atmospheric pressure is applied to the pressure transmission path of the supercharging intake pressure to the pressure chamber in the wastegate valve. is transmitted to the pressure chamber,
A configuration is provided in which a switching means is provided for switching the supercharging intake pressure to be directly transmitted to the pressure chamber when the mechanical supercharger is in operation.

[For production]

In such a configuration, when the internal combustion engine is in a low speed range,
As the mechanical supercharger rotates and the on-off valve in the intake bypass passage is closed, the mechanical supercharger is activated, and supercharging of the internal combustion engine is carried out between the exhaust turbo supercharger and the mechanical supercharger. On the other hand, it is carried out by both a type supercharger and
In this low-speed rotation range, the supercharging intake pressure for the internal combustion engine is directly transmitted to the pressure chamber of the wastegate valve in the exhaust bypass passage, and the wastegate valve opens wide, greatly increasing the supercharging operation by the exhaust turbo supercharger. Therefore, it is possible to prevent the supercharging pressure for the internal combustion engine from increasing significantly beyond a predetermined set supercharging pressure as the rotational speed increases.

In addition, when the internal combustion engine is in a high-speed rotation range, the rotational drive of the mechanical supercharger stops, and the on-off valve opens, stopping supercharging by the mechanical supercharger. While this is achieved only by the exhaust turbo supercharger, in this high-speed rotation range, the pressure chamber of the wastegate valve in the exhaust bypass passage is cut so that the combined pressure of the supercharging intake pressure and atmospheric pressure for the internal combustion engine acts. As a result, the pressure acting on the pressure chamber becomes lower than in the low speed rotation range, and the opening degree of the wastegate valve becomes smaller. In this state, the supercharging intake pressure for the internal combustion engine is reduced. The intake pressure is controlled so that it does not exceed a predetermined set supercharging pressure.

〔Effect of the invention〕

As described above, when the mechanical supercharger is not operating, the supercharging is performed by applying a composite pressure of the supercharging intake pressure and atmospheric pressure to the internal combustion engine to the pressure chamber in the waste gate valve. While the intake pressure is controlled so that the supercharging intake pressure does not exceed a predetermined set supercharging pressure, when the mechanical supercharger is operating, the pressure chamber in the wastegate valve is filled with the supercharging intake pressure for the internal combustion engine. The wastegate valve is opened wide by applying atmospheric pressure as it is. This can greatly reduce the supercharging operation by the exhaust turbo supercharger, and the supercharging pressure to the internal combustion engine is Since it is possible to prevent the boost pressure from increasing significantly beyond the predetermined set boost pressure due to an increase in the number of boosters, it is possible to reduce fluctuations in the output of the internal combustion engine, improve drivability, and cause problems such as knocking due to overcharging. It has the effect of reliably preventing the occurrence of.

〔Example〕

Hereinafter, embodiments 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 port 3 to the combustion chamber 2 and an exhaust port 4 from the combustion chamber, and 5 indicates an exhaust turbine. 6 and a blower-compressor 7 are directly connected to each other, and reference numeral 8 indicates a mechanical supercharger which is rotatably driven by power transmitted from the internal combustion engine 1.

An exhaust passage 9 from the exhaust port 4 of the internal combustion engine 1 is connected to the inlet side of the exhaust turbine 6 in the exhaust turbo supercharger 5, and an exhaust passage 9 from the exhaust port 4 of the internal combustion engine 1 is connected to the inlet side of the exhaust turbine 6 of the exhaust turbo supercharger 5. Exhaust pipes IO are connected to each other, and between the exhaust pipe 9 and the exhaust pipe IO, there is an exhaust gas passage 11 that bypasses the exhaust turbine 6.
A wastegate valve 13 is provided in the exhaust bypass passage 11 and is normally held closed by a spring 12a within the diaphragm mechanism 12.

Furthermore, an air cleaner 14 that does not take in atmospheric air is connected to the inlet of the blower-compressor 7 in the exhaust turbo supercharger 5, and furthermore, an air cleaner 14 is connected to the inlet of the blower-compressor 7 in the exhaust turbo supercharger 5. The power transmission section is provided with an electromagnetic clutch mechanism 15 for turning on and off power transmission to the mechanical supercharger 8.

A surge tank 18 having a throttle body 17 with a built-in throttle valve 16 is connected to the intake port 3 of the internal combustion engine 1, while a surge tank 18 is connected to the intake port 3 of the internal combustion engine 1.
Intake passage 19 from the discharge port of the blower compressor 7 in
is connected to the inlet of the mechanical supercharger 8, and the outlet of the mechanical supercharger 8 is connected to the throttle body 17 of the surge tank 18 via a supercharging passage 21 provided with an intercooler 20. Further, the intake passage 1
9 and the supercharging passage 21, the mechanical supercharger 8
An intake bypass passage 22 is provided to bypass the intake air, and an on-off valve 24 that is normally kept closed by a spring 23a of a diaphragm mechanism 23 is provided in the intake bypass passage 22.

On the other hand, the diaphragm mechanism 1 of the waste gate valve 13
A pressure transmission passage 25 with a throttle orifice 26 from the supercharging passage 21 is connected to the pressure chamber 12b in 2,
When the pressure acting on the pressure chamber 12b becomes higher than a predetermined supercharging intake pressure, the wastegate valve 1
3 is configured to open, and an atmosphere communication passage 27 with a throttle orifice 28 from an atmosphere communication point such as the air crevice 14 is connected to the pressure transmission passage 25, and the atmosphere communication passage 27 is connected to the atmosphere communication passage 27. An electromagnetic switching valve 29 is provided to open and close the passage 27.

Further, in the diaphragm mechanism 23 for the on-off valve 24, a pressure transmission passage 30 from the supercharging passage 21 is connected to one pressure chamber 23c partitioned by the diaphragm 23b.
The on-off valve 24 is configured to open against the spring 23a when the supercharging intake pressure in the supercharging passage 21 increases, while the pressure transmission passage to the other pressure chamber 23d in the diaphragm mechanism 23 is connected to the 31 and a pressure transmission passage 32 from the surge tank 18 and a pressure transmission passage 33 from the supercharging passage 21, three types of first electromagnetic switching valves 34 are provided.

Furthermore, a vacuum holding tank 35 is connected to the surge tank 18 through a passage 36, and a check valve 37 is provided in the passage 36, which opens only in the direction toward the surge tank 18.
By providing a vacuum pressure lower than atmospheric pressure in the vacuum holding tank 35, a vacuum transmission passage 38 from the vacuum holding tank 35 and the first electromagnetic switching valve 3 are provided.
A second electromagnetic switching valve 39 of three types is provided between the pressure transmitting passage 33 and the pressure transmission passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33 to the pressure transmitting passage 33.

Reference numeral 40 denotes a rotation sensor 41 for the internal combustion engine 1. In response to detection signals from the opening sensor 42 for the throttle valve 16 and the pressure sensor 43 for the surge tank 18
5 and the three types of electromagnetic switching valves 29 and both of the three types of electromagnetic switching valves 34 and 39, as described below.

In other words, this control circuit 40 operates when the rotational speed of the (I)6 internal combustion engine 1 is 3500 to 400.
When the operating speed is low, lower than a medium rotation speed of about 0 rpm, and the operating load is high, the electromagnetic clutch mechanism 15 is turned on, the three types of electromagnetic switching valves 29 are closed, and the first electromagnetic switching valve 34 is set to pressure. A first switching state is established in which only the transmission passages 31 and 32 communicate with each other.

(■) When the load is low and the rotational speed is in a low-speed operation range lower than the medium-speed rotational speed, the electromagnetic clutch mechanism 15
is turned OFF and the three types of electromagnetic switching valves 29 are closed, while the first electromagnetic switching valve 34 is used to cut off the communication between the pressure transmission passages 31 and 32 and only between the pressure transmission passages 31 and 33. The second electromagnetic switching valve 39 is brought into a first switching state in which the pressure transmission passage 33 and the vacuum transmission passage 38 are disconnected from each other and the pressure transmission passage 33 is brought into communication.

(■) When the load is high and the rotation speed is in a high speed operation range higher than the medium speed rotation speed, the electromagnetic clutch mechanism 15
OFF and switch the three-way electromagnetic switching valve 29 to open, while keeping the first electromagnetic switching valve 34 in the second switching state, and switch the second electromagnetic switching valve 39 between the pressure transmission passage 33 and the vacuum transmission passage 38. A second switching state is established in which the two terminals are in communication with each other.

(■) When operating under low load and high speed rotation, the electromagnetic clutch mechanism 15 is turned OFF and the three-way electromagnetic switching valve 29 is switched to open, while the first electromagnetic switching valve 34 is switched to the second switching state. While keeping the switch in place, the second electromagnetic switching valve 39 is set to the first switching state.

It is configured as follows.

In this configuration, when the internal combustion engine rotates at low speed and is in a high load operating range, the electromagnetic clutch mechanism 15 is turned on and the mechanical supercharger 8 is rotationally driven, while the first electromagnetic switching valve 34 is In the switching state, the supercharging intake pressure in the surge tank 18 is transferred to the other pressure chamber 23d in the diaphragm mechanism 23 for the on-off valve 24 (at this time, the supercharging intake pressure in the surge tank 18 is
6 is substantially fully open, a supercharging intake pressure (approximately equal to the supercharging intake pressure in the supercharging passage 21) acts on the other pressure chamber 2.
3b, and one pressure chamber 2 in which the supercharging intake pressure in the supercharging passage 21 is constantly acting via the pressure transmission passage 30.
3c, the on-off valve 24 is closed by the spring 23a, so that the internal combustion engine 1 is supercharged by both the exhaust turbo supercharger 5 and the mechanical supercharger 8. It is carried out by

On the other hand, in this operating range, the three-way electromagnetic switching valve 29 is closed, so that the supercharging intake pressure in the supercharging passage 21 directly acts on the pressure chamber 12b in the diaphragm mechanism 12 for the waste gate valve 13. Therefore, the wastegate valve 13 opens widely when the supercharging intake pressure in the supercharging passage 21 exceeds the set value of the spring 12a that urges the wastegate valve 13 to close.
Control the supercharging intake pressure so that it does not increase significantly.

Next, when the internal combustion engine 1 is in a low-speed rotation and low-load operating range, the electromagnetic clutch mechanism 15 is turned off and power transmission to the mechanical supercharger 8 is cut off, while the first electromagnetic switching valve 34 is in the second switching state, and the second electromagnetic switching valve 39 is in the first switching state, and the supercharging intake pressure in the supercharging passage 21 acts on the other pressure chamber 23d in the diaphragm mechanism 23 for the on-off valve 24. The pressure difference between the other pressure chamber 23d and one pressure chamber 23c disappears, and the on-off valve 24 is closed by the spring 23a, so that the supercharged air compressed in the exhaust turbo supercharger 5 is transferred to the mechanical supercharger. Since it is sent to the charger 8, this causes the mechanical supercharger 8 to
While the follow-up rotation can be performed at an appropriate speed, the supercharging intake pressure in this operating range is also controlled so as not to increase significantly by only the supercharging intake pressure in the supercharging passage 21, as described above.

Further, when the internal combustion engine 1 is in a high-speed rotation and low-load operating range, the electromagnetic clutch mechanism 15 is turned off and power transmission to the mechanical supercharger 8 is cut off, while the first electromagnetic switching valve 34 is turned off. In the second switching state, the second electromagnetic switching valve 39 becomes the first switching state, and the on-off valve 24 is closed by the spring 23a, so that the supercharged air compressed in the exhaust turbo supercharger 5 is transferred to the mechanical supercharger. Since it is sent to feeder 8, as a result,
The mechanical supercharger 8 can follow the rotation at an appropriate speed.

On the other hand, in this operating range, the three-way electromagnetic switching valve 29 opens, so that the pressure chamber 12b in the diaphragm mechanism 12 for the wastegate valve I3 is connected to the supercharging intake pressure in the supercharging passage 21 and the atmospheric pressure. When a composite pressure is applied and this composite pressure exceeds the set value of the spring 12a that urges the wastegate valve 13 to close, the wastegate valve 13 opens and the exhaust gas is transferred to the exhaust bypass passage 11.
As a result, the supercharging passage 2
The supercharging intake pressure in the engine 1 can be controlled by the combined pressure so that it does not exceed a predetermined set supercharging intake pressure. Note that this combined pressure can be arbitrarily set by selecting the diameter ratio of both throttle orifices 26,28.

When the internal combustion engine 1 is in a high-speed rotation and high-load operating range, the electromagnetic clutch mechanism 15 is turned off and power transmission to the mechanical supercharger 8 is cut off, while the first electromagnetic switching valve 34 is turned off. In the second switching state, the second electromagnetic switching valve 39 is in the second switching state.
In the switching state, the vacuum in the vacuum holding tank 35 is transmitted to the other pressure chamber 23d in the diaphragm mechanism 23 for the on-off valve 24, and the vacuum in the vacuum holding tank 35 is transferred to the other pressure chamber 23d.
A pressure difference is created between the two pressure chambers 23c and 23c, and this pressure difference opens the on-off valve 24, so the supercharged air from the exhaust turbocharger 5 passes through the mechanical supercharger 8. Instead, air is taken into the internal combustion engine 1 via the intake bypass passage 22, and supercharging is performed only by the exhaust turbo supercharger 5, and the following rotation of the mechanical supercharger 8 is not performed. The supercharging intake pressure at this time can also be controlled by the composite pressure so as not to exceed a predetermined set supercharging intake pressure, as described above.

[Brief explanation of drawings]

The drawings are diagrams showing embodiments of the invention.

Claims (1)

[Claims] (1) In the intake path from the air cleaner to the internal combustion engine, there is a mechanical supercharger that is driven by power transmission from the internal combustion engine only in the low speed range below the medium speed range, and an exhaust that is driven by exhaust gas. A turbo supercharger is arranged in series, and an on-off valve is provided in an intake bypass passage that bypasses the mechanical supercharger and is closed when the mechanical supercharger is driven to rotate. A composite supercharging device comprising a pressure-operated wastegate valve that opens when supercharging intake pressure for an internal combustion engine acts on a pressure chamber in an exhaust bypass passage that bypasses an exhaust turbine in an exhaust turbo supercharger. In the wastegate valve, a pressure transmission passage for the supercharging intake pressure to the pressure chamber is configured to transmit a combined pressure of the supercharging intake pressure and atmospheric pressure to the pressure chamber when the mechanical supercharger is not operating. A composite supercharging device for an internal combustion engine, characterized in that a switching means is provided for switching to transmit the supercharging intake pressure as it is to the pressure chamber when the mechanical supercharger is in operation.