JP2006170060A - Supercharging device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accelerating performance at low speed or with low load, to reduce black smoke, to improve startability at low temperatures, and to reduce blue-white smoke at low temperatures. <P>SOLUTION: An air supply passage 10 is provided with a displacement compressor 21 driven by an electric motor 25 and a bypass passage 11 bypassing the displacement compressor 21. A check valve 22 is arranged in the bypass passage 11 for stopping a reverse flow of supplied air from the air supply inlet port side of an engine. The check valve 22 is structured to close the bypass passage 11 while the displacement compressor 21 is operating and boosting the supplied air, and when the supplied air is no longer boosted by the displacement compressor 21, to open the bypass passage 11 to make the supplied air flow from the supplied air upstream side to the supplied air inlet port side of the engine. When the supercharging device is equipped with an exhaust air turbo supercharger 13, the displacement compressor 21 and the check valve 22 are arranged in parallel on the supplied air downstream side of a compression part 15 of the exhaust air turbo charger 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a supercharging device for an internal combustion engine provided with an electric compressor driven by an electric motor.

  In an internal combustion engine, in order to improve engine performance such as improvement in acceleration performance at low speed and low load, a conventional engine having a variable displacement exhaust turbocharger (see Patent Document 1) or an exhaust turbocharger Some have an electric compressor driven by an electric motor together with a feeder (see Patent Document 2).

  FIG. 15 shows an internal combustion engine equipped with the former variable displacement exhaust turbocharger. A turbine section 104 of an exhaust turbocharger 103 is arranged in an exhaust passage 102 of the internal combustion engine 101, and The compression unit 105 of the exhaust turbocharger 103 is arranged, the turbine unit 104 includes a variable nozzle 108, and the turbine capacity is changed by adjusting the nozzle opening according to the operating conditions. Yes.

  FIG. 16 is a diagram showing the relationship between the air flow rate and the pressure ratio of the compression part of the exhaust turbocharger, and the point A0 is an engine operating point at low speed and low load, such as idling rotation. If a fixed-capacity exhaust turbocharger is provided and if acceleration is performed from the state of the A0 point, the air flow rate and pressure ratio change from line A0 → A1 → D1, and bear the load. This line is determined by exhaust temperature limits or black smoke limits. On the other hand, when the variable displacement exhaust turbocharger 103 shown in FIG. 15 is provided, the variable nozzle 108 is reduced during acceleration to reduce the turbine capacity, and the variable nozzle 108 is opened after the engine acceleration is completed. By increasing the turbine capacity, the air flow rate and pressure ratio of the compression unit 105 change from line A0 → A1 → A2 → D2 → D1. That is, the time required for rising can be shortened, and acceleration performance during low-speed rotation can be improved.

  FIG. 17 shows an internal combustion engine to which the latter electric compressor is added. The turbine section 204 of the exhaust turbocharger 203 is disposed in the exhaust passage 202 of the internal combustion engine 201, and the exhaust turbo is disposed in the supply passage 210. A compression unit 205 of the supercharger 203 is arranged. Further, an electric compressor (supercharger) 212 driven by an electric motor 211 is disposed in the air supply passage 210, and a bypass passage 215 that bypasses the compressor 212 is provided, and the bypass passage 215 is bypassed. A valve 216 is provided. The bypass valve 216 is opened / closed by an actuator 217, and the actuator 217 is electrically connected to the engine control unit 218 and is controlled to be opened / closed by a command from the engine control unit 218. 220 is a throttle valve and 222 is an air flow meter.

In the case of the internal combustion engine of FIG. 17, the electric compressor 212 is operated when the exhaust turbocharger 203 cannot sufficiently supercharge like a region where the engine speed is low, that is, a region where a so-called turbo lag occurs. Accelerating performance at low speeds is improved.
Japanese Patent Laid-Open No. 9-329032 JP 2004-76659 A

  In the former configuration in which the turbine section 104 of the exhaust turbocharger 103 is of a variable displacement type as in the internal combustion engine of FIG. 15, when the turbine capacity is reduced in the low speed rotation range, the line A0 → A1 in FIG. → As in A2, it is possible to get up in a short time and obtain a high pressure ratio, but at the time of starting up (A2 point), it approaches the surge line of the exhaust turbocharger. Therefore, even though the latest high-pressure injection technology can move the limit of black smoke to a higher pressure side, it is subject to fuel limitation due to surging. On the other hand, if the surge line is moved to the high pressure, low flow rate side and the engine operating range is to be expanded, complicated measures for surging must be taken, the configuration becomes complicated and the cost increases. .

  The latter, like the internal combustion engine of FIG. 17, needs to include an actuator 217 for opening and closing the bypass valve 216 and an engine control unit 218 in an internal combustion engine including the electric compressor 212 and the bypass valve 216. Must include a program for controlling the opening and closing of the bypass valve, and further includes an air flow meter 222 for measuring the air flow rate as a parameter of the bypass valve control condition. That is, parts for driving and controlling the bypass valve are required, the cost is increased, and the structure is complicated.

[Object of invention]
The object of the present invention is to improve the acceleration performance in the low-speed rotation range without taking special measures against surging, suppress the generation of black smoke and blue / white smoke during acceleration, and reduce the cost of the air supply control member. It is to reduce and simplify the structure. Another object is to improve low temperature startability and reduce blue-white smoke at the start.

  In order to solve the above-mentioned problem, according to the first aspect of the present invention, a positive displacement compressor driven by an electric motor is provided in the air supply passage, and a bypass passage that bypasses the positive displacement compressor is provided, and the bypass passage is provided in the bypass passage. Is provided with a check valve for preventing the backflow of the supply air from the air supply port side of the engine, and the check valve opens the bypass passage while the positive displacement compressor is operated to increase the supply air. It is closed, and when the boosting of the supply air by the positive displacement compressor disappears, the check valve is opened to supply the supply air to the intake port side of the engine.

  According to a second aspect of the present invention, in the supercharging device for an internal combustion engine according to the first aspect, the compression portion of the exhaust turbocharger is disposed in the air supply passage, and the air supply passage portion on the downstream side of the air supply from the compression portion And a bypass passage having the check valve and the positive displacement compressor is provided in a portion of the air supply passage downstream of the air supply cooling device.

According to a third aspect of the present invention, in the supercharging device for an internal combustion engine according to the first or second aspect,
Acceleration state detection means for detecting the acceleration state of the engine rotation is provided, and the positive displacement compressor is operated when the acceleration state is detected.

  According to a fourth aspect of the present invention, in the supercharging device for an internal combustion engine according to any one of the first to third aspects, the check valve is a ball type check valve in which a movable ball is seated on a valve seat. is there.

  According to a fifth aspect of the present invention, in the supercharging device for an internal combustion engine according to any one of the first to third aspects, the check valve is a check in which a rotatable plate-shaped valve body is seated on a valve seat. It is a valve.

  According to a sixth aspect of the present invention, in the supercharging device for an internal combustion engine according to any one of the first to fifth aspects, a differential pressure detection that detects a differential pressure between the upstream side and the downstream side of the supply air of the check valve. Means are disposed in the bypass passage, and the positive displacement compressor is stopped when the detected differential pressure becomes a predetermined value or less during operation of the positive displacement compressor.

  According to a seventh aspect of the present invention, in the supercharging device for an internal combustion engine according to the fifth aspect of the present invention, opening degree detecting means is provided for detecting the opening degree by the amount of rotation of the plate-like valve body, and the positive displacement compressor is operating. The electric positive displacement compressor is stopped when the opening degree of the plate-like valve element becomes a predetermined value or more.

  The invention according to claim 8 is the supercharging device for the internal combustion engine according to claim 5, wherein the valve seat and the plate-like valve body of the check valve are provided with contacts that are energized when seated and de-energized when not seated. In addition, energization detecting means for detecting energization and de-energization is provided, and when the non-energized state is detected while the positive displacement compressor is operating, the positive displacement compressor is stopped.

  According to a ninth aspect of the present invention, in the supercharging device for an internal combustion engine according to any one of the first to eighth aspects, the air capacity of the positive displacement compressor is smaller than the rated air amount of the internal combustion engine.

  According to a tenth aspect of the present invention, in the supercharging device for an internal combustion engine according to the first aspect, a compression portion of the exhaust turbocharger is disposed in the supply passage, and a supply passage portion downstream of the supply portion from the compression portion. The positive displacement compressor is disposed at the same time, a bypass passage that bypasses the positive displacement compressor is provided, and a supply air cooling device is disposed in a bypass passage portion upstream of the check valve.

  According to a eleventh aspect of the present invention, in the supercharging device for an internal combustion engine according to the tenth aspect, an engine air supply temperature detecting means is provided, and the positive displacement compressor is operated when the engine air supply temperature is a predetermined value or less. ing.

  According to a twelfth aspect of the present invention, in the supercharging device for the internal combustion engine according to the tenth aspect, the engine cooling water temperature detecting means is provided, and the positive displacement compressor is operated when the engine cooling water temperature is a predetermined value or less. Yes.

A thirteenth aspect of the present invention is the internal combustion engine supercharging device according to the eleventh or twelfth aspect,
Exhaust valve lift adjustment means is provided to reduce the exhaust valve lift when the engine supply air temperature or the engine coolant temperature is below a predetermined value.

The invention as set forth in claim 14 is the supercharging device for an internal combustion engine according to claim 11 or 12,
An exhaust valve opening / closing timing adjusting means is provided to delay the exhaust valve opening timing when the engine supply air temperature or the engine coolant temperature is below a predetermined value.

  According to a fifteenth aspect of the present invention, in the supercharging device for the internal combustion engine according to the eleventh or twelfth aspect, the exhaust turbocharger has a variable turbine capacity, and the engine supply air temperature or the engine coolant temperature is The turbine capacity of the exhaust turbocharger is reduced when the value is below a predetermined value.

  According to a sixteenth aspect of the present invention, in the supercharging device for an internal combustion engine according to the eleventh or twelfth aspect, a throttle means for making the exhaust outlet cross-sectional area variable is provided in the turbine portion of the exhaust turbocharger, and the engine air supply When the temperature or the engine cooling water temperature is equal to or lower than a predetermined value, the exhaust outlet cross-sectional area is throttled by the throttle means.

(1) Since an electric positive displacement compressor that does not use exhaust gas pressure is provided in the air supply passage, by temporarily operating the positive displacement compressor during low speed rotation, low load, or cold start It is possible to improve the acceleration performance in the low-speed rotation region and the acceleration performance at the low temperature start, reduce the generation of black smoke during acceleration, and reduce the generation of blue-white smoke.

(2) By arranging a check valve in parallel with the positive displacement compressor and opening the bypass passage by the pressure on the upstream side of the check valve when the pressure increase by the positive displacement compressor is almost eliminated As in the conventional example of FIG. 17, it is not necessary to provide an actuator for driving the bypass valve, a control mechanism, etc., and the structure is simplified and the part cost can be reduced.

(3) By opening the check valve when the boosting of the supply air by the electric positive displacement compressor disappears, the air flowing through the bypass passage is automatically used after the acceleration is completed. A normal air supply state can be maintained.

(4) In an internal combustion engine provided with an exhaust turbocharger, the electric positive displacement compressor and a check valve are provided in parallel on the supply downstream side of the compression portion of the exhaust turbocharger. Thus, when the positive displacement compressor is driven and accelerated in the low speed rotation region, the air discharged from the compression unit of the exhaust turbocharger is further boosted by the positive displacement compressor, and the entire supercharging system This makes it possible to supply air to the engine at a pressure higher than the surge line of the exhaust turbocharger without taking countermeasures for surging. Compared to the conventional example of FIG. Obtainable.

  More specifically, FIG. 9 shows the relationship (map) between the air flow rate and the pressure ratio of the compressor of the exhaust turbocharger, and the middle row shows the relationship between the air flow rate and the pressure ratio of the positive displacement compressor. (Map) is shown, and the upper part shows the relationship (map) between the air flow rate and pressure ratio of the entire turbocharging system consisting of the compression part of the exhaust turbocharger and the positive displacement compressor, and the positive displacement compressor is operated. The operating point is A point in the lower map, and B point in the middle map, and the air exiting the compression part of the exhaust turbocharger is further boosted by the positive displacement compressor. In the map of FIG. As a result, the engine can be supplied with air at a pressure higher than the surge line S0 of the exhaust turbocharger, more fuel can be supplied than in the conventional example, and a large acceleration torque can be obtained. The curve S1 is a surge line as the entire supercharging system.

(5) When the acceleration state is detected by the acceleration state detection means, by operating the electric positive displacement compressor, it is possible to automatically increase the supply air pressure during acceleration.

(6) By using a ball type check valve or a check valve that rotatably supports a plate-like valve body as the check valve, the cost of components can be reduced.

(7) In order to stop the operation of the positive displacement compressor, a differential pressure detecting means for detecting a differential pressure between the upstream and downstream of the check valve, and a check valve for detecting the rotation amount of the rotatable plate-shaped valve body Energization detection means for detecting energization / non-energization between the opening degree detection means or the plate-shaped valve body and the valve seat is provided, and the check valve is opened by these detection means, and the supply air flows in the bypass passage When the state is detected, the electric displacement type compressor is stopped, so that after the displacement type compressor is operated, when the compression action by the displacement type compressor becomes unnecessary, it is automatically performed. The positive displacement compressor can be stopped quickly and energy can be saved.

(8) By providing an electric positive displacement compressor having a capacity smaller than the rated air amount of the internal combustion engine, the supercharger can be reduced in size and cost, and at a low speed rotation region using the positive displacement compressor. It is possible to smoothly shift from the acceleration state to the high-speed rotation range using only the exhaust turbocharger.

(9) While a check valve and a charge air cooling device are arranged in a bypass passage that bypasses the positive displacement compressor arranged on the downstream side of the intake air of the exhaust turbocharger and the positive displacement compressor is used Since the check valve is closed so that the supply air does not pass through the supply air cooling device, the supply air is not cooled while the pressure is increased by the positive displacement compressor, and the blue and white smoke is reduced. be able to.

(10) In the configuration in which the supply air cooling device is arranged in the bypass passage together with the check valve, the positive displacement compressor is operated when the engine supply air temperature is lower than the predetermined value or when the engine cooling water temperature is lower than the predetermined value. By doing so, it is possible to start without automatically cooling the supply air at the time of cold start, and the cold start performance is improved.

(11) In the configuration in which the supply air cooling device is arranged in the bypass passage together with the check valve, the exhaust valve lift is reduced when the engine supply air temperature or the engine cooling water temperature is equal to or lower than a predetermined value, or the exhaust valve opening timing By suppressing the exhaust gas emission amount, the exhaust gas emission amount can be suppressed, the exhaust gas residual amount can be increased, the cylinder periphery can be heated by the heat of the residual exhaust gas, and the warm-up operation time can be shortened. it can.

(12) In the configuration in which the supply air cooling device is arranged in the bypass passage together with the check valve, an exhaust turbocharger having a variable turbine capacity is provided, and the engine supply air temperature or the engine coolant temperature is a predetermined value or less. Since the turbine capacity is sometimes reduced, the amount of exhaust gas can be suppressed, the residual amount can be increased, and the surrounding exhaust gas can be heated quickly by the heat of the residual exhaust gas, thereby shortening the warm-up operation time. The

(13) In the configuration in which the supply air cooling device is arranged in the bypass passage together with the check valve, the cross-sectional area of the exhaust passage is reduced when the engine supply air temperature or the engine cooling water temperature is a predetermined value or less. The amount of exhaust gas discharged can be suppressed to increase the residual amount, the cylinder periphery can be heated quickly by the heat of the exhaust gas, and the warm-up operation time can be shortened.

[First Embodiment of the Invention]
(Constitution)
FIG. 1 shows a first embodiment of the present invention, which is an example in which the present invention is applied to a reciprocating internal combustion engine equipped with an exhaust turbocharger 13. In the combustion chamber 1a of the internal combustion engine 1, an exhaust port 2 and an air supply port 3 are opened, and a fuel injection nozzle portion 6 faces. The exhaust port 2 is connected to an exhaust passage 12 and an exhaust valve 4 that can be opened and closed. The air supply port 3 is connected to an air supply passage 10 and an open and close air supply valve 5 is disposed. A fuel supply passage 8 is connected to the injection nozzle portion 6.

  A throttle valve 9 is rotatably disposed in the fuel supply passage 8, and acceleration state detection means 30 is provided for detecting an acceleration state by detecting a rotation position (throttle opening) of the throttle valve 9. The acceleration state detection means 30 is electrically connected to the engine control unit 33, and transmits an acceleration state detection signal to the engine control unit 33 when the throttle opening exceeds a certain value, that is, when the acceleration state is detected. It is supposed to be.

  A turbine portion 14 of an exhaust turbocharger 13 is disposed in the exhaust passage 12.

  In the air supply passage 10, a compression unit 15 of the exhaust turbo supercharger 13 is arranged, and an air supply cooling device 20 such as an intercooler is arranged downstream of the compression unit 15, and further, the air supply An electric positive displacement compressor 21 is disposed in the supply passage portion 10a on the downstream side of the cooling device 20, and a bypass passage 11 that bypasses the positive displacement compressor 21 is provided. A ball type check valve 22 is disposed in the passage 11.

  The inlet of the check valve 22 on the upstream side of the supply air is provided with a supply air flow detection means 31 for detecting the flow of the supply air. The supply air flow detection means 31 is electrically connected to the engine controller unit 33 and bypassed. A supply air flow detection signal is transmitted to the engine control unit 33 when the supply air flows through the passage 11.

  The positive displacement compressor 21 is connected to a DC electric motor 25 and is driven by the electric motor 25, and the electric motor 25 is electrically connected to the engine control unit 33. ON / OFF control is performed by the drive signal and stop signal. The positive displacement compressor 21 has a capacity smaller than the rated air amount of the internal combustion engine 1, and the drive motor 25 also has a small capacity corresponding to this.

  The check valve 22 is a ball-type check valve in which a movable ball 27 is seated on a valve seat 26, and prevents the backflow of the supply air from the supply port 3 side of the engine 1 and the supply of air. The supply air can be circulated by pushing the ball 27 open only from the air upstream side to the air supply port 3 side.

(Control content)
The air supply detection means 31 determines the presence or absence of the air supply by detecting the dynamic pressure of the supply air in the bypass passage 11. If the dynamic pressure is greater than a predetermined value, the check valve 27 is opened. It is determined that the supply air is flowing, and a supply air flow detection signal is transmitted to the engine control unit 33 as described above.

  The acceleration state detection means 30 detects the opening degree of the throttle valve 9 as described above. If the throttle opening degree is not less than a predetermined value, the acceleration state detection means 30 determines that the acceleration state is present and transmits an acceleration state detection signal to the engine control unit 33. To do.

  The electric motor 25 of the positive displacement compressor 21 can be arbitrarily driven by an operator. However, in principle, when the acceleration state detecting means 30 detects an acceleration state, the electric motor 25 is driven by a drive signal from the engine control unit 33. Further, when the air supply air flow in the bypass passage 11 is detected by the air supply air flow detecting means 31 during operation of the electric motor, the operation is stopped by a stop signal from the engine control unit 33. Yes.

(Operation)
(1) In FIG. 1, during low speed operation such as idling or during low load operation, the positive displacement compressor 21 is stopped and the air supply passage portion 10 a is blocked by the positive displacement compressor 21. The air slightly pressurized by the compression unit 15 of the exhaust turbocharger 13 pushes up the ball 27 of the check valve 22 to open the bypass passage 11 and passes through the bypass passage 11 to the air supply port 3 of the engine 1. Supplied.

(2) When the throttle valve 9 is opened to a predetermined value or more and accelerated from the state of low speed operation or the like, the acceleration state detection means 30 detects the acceleration state and transmits an acceleration state detection signal to the engine control unit 33, The electric motor 25 is driven by a drive signal from the control unit 33. Thereby, the positive displacement compressor 21 starts to rotate. Since the supply air that cannot pass through the positive displacement compressor 21 at the beginning of the operation of the positive displacement compressor 21 still passes through the bypass passage 11, the supply air passes through both the supply passage portion 10 a and the bypass passage 11. The supply air is supplied to the mouth 3.

(3) When the rotational speed of the positive displacement compressor 21 increases and the supply air pressure is increased by the positive displacement compressor 21, the check valve 22 is connected to the supply air downstream side (supply air port 3 side). By increasing the pressure, the bypass passage 11 is closed, and the supply air is supplied only from the supply passage portion 10a, so that the pressure can be further increased. At this time, the outlet pressure of the compression unit 15 of the exhaust turbo supercharger 13 is lower than when the positive displacement compressor 21 on the downstream side of the supply air is not present, and therefore the acceleration of the turbine shaft 13a is faster. .

(4) When the acceleration progresses and the rotational speed of the exhaust turbocharger 13 increases and the amount of air discharged from the compression unit 15 exceeds the capacity of the positive displacement compressor 21, the positive displacement compressor 21 Excess air that cannot resist the positive displacement compressor 21 due to the resistance to the supply air from the compression unit 15 of the exhaust turbocharger 13 pushes the check valve 22 of the bypass passage 11 and flows through the bypass passage 11. .

(5) When the supply air begins to flow into the bypass passage 11 as described above, the supply air flow detecting means 31 detects the supply air flow, whereby a stop signal is sent from the engine control unit 33 to the electric motor 25, and the electric motor 25. The power supply to is cut off, and the positive displacement compressor 21 stops operating. As a result, all the air discharged from the compression unit 15 of the exhaust turbocharger 13 is supplied to the intake port 3 through the bypass passage 11. Thus, in response to the sudden increase in load, the air amount and the fuel amount can be instantaneously increased to obtain a large torque, and good responsiveness during acceleration can be obtained.

(Effect in the embodiment)
(1) As described above, the compressor 21 arranged in the air supply passage 10 has a small capacity smaller than the rated air amount of the engine and is a positive displacement compressor driven by a DC electric motor 25. In the transition from the low speed rotation to the high speed rotation, it is possible to smoothly shift from the supercharging action in which the pressurizing action by the positive displacement compressor 21 is added to the supercharging action by only the exhaust turbocharger 13. More specifically, FIG. 10 is a diagram showing changes in voltage, torque, and rotational speed with respect to current changes in the DC electric motor 25. When the supply voltage is constant, the torque decreases as the rotational speed increases. It has become a relationship. Therefore, the pressure ratio of the positive displacement compressor 21 driven by the DC electric motor 25 decreases as the rotational speed increases, as indicated by the line X1 (B1->B2->B3-> B4) in FIG. Become. When this line X1 (B1->B2->B3-> B4) is shown on the map of the exhaust turbocharger 13, it becomes a line X1 (C1->C2->C3-> C4) as shown in FIG. 12, and is equipped with a positive displacement compressor. Compared with the output limit line X0 of the exhaust turbocharger when not, an increase in the pressure ratio in the shaded area is obtained, and the amount of increase in pressure gradually increases with increasing rotational speed (increasing air flow rate). By decreasing, the pressure is smoothly shifted from the low speed rotation range to the pressure ratio of the rated rotation speed (points A4 and C4) by only the exhaust turbocharger 13. That is, the capacity of the compressor 21 is set to be smaller than the air capacity at the rated rotation of the internal combustion engine, and a positive displacement type that functions as a shut-off valve when stopped is used. Therefore, when the transition from the low speed rotation region to the high speed rotation region is performed, the check valve 22 is automatically opened by the compressor 21 being stopped, and the check valve 22 is operated only at the low speed. Supply system can be provided.

(2) Since the bypass passage 11 is opened and closed by the check valve 22 that automatically opens and closes according to the pressure change in the bypass passage 11, the supercharging control is performed by the electric motor 25 of the positive displacement compressor 21. Only the voltage is required, and the actuator for driving the bypass valve and the control means for control are not required as in the conventional bypass valve, and the structure is simplified.

(3) When the internal combustion engine as shown in FIG. 1 is applied to an emergency power generation diesel engine, for example, a detection mechanism for detecting a power failure in a building where the engine is installed is electrically connected to the engine control unit. When an electric power failure is confirmed, the electric motor can be driven. Thereby, the starting time of the engine at the time of a power failure can be shortened.

[Second Embodiment of the Invention]
(Configuration and operation)
FIG. 2 shows a second embodiment of the present invention, which is an example applied to an internal combustion engine not equipped with an exhaust turbocharger. Except for not including an exhaust turbocharger and an air supply / cooling device, the structure is the same as that shown in FIG. 1, and the same components and parts are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 2, a positive displacement compressor 21 driven by an electric motor 25 is disposed in the air supply passage 10, and a bypass passage 11 that bypasses the positive displacement compressor 21 is provided, and a check valve 22 is provided in the bypass passage 11. Provided.

  The operation is the same as that in FIG. 1 except that the supercharging action by the exhaust turbocharger is not applied, and it is possible to improve the acceleration performance and simplify the structure.

[Modification of check valve and check valve opening / closing detection means]
(1) FIG. 3 shows an example in which a pressure check means 38 is provided in the ball check valve 22 in place of the air supply detection means 31 as shown in FIG. The differential pressure detecting means 38 has a pressure sensor 38a provided on the upstream side of the supply air with respect to the valve seat 26 and a pressure sensor 38b provided on the downstream side of the supply air, and the pressure difference between the upstream and downstream becomes almost zero. When the check valve 22 is detected, it is determined that the check valve 22 is open and the air supply is flowing through the bypass passage 11, and a check valve open detection signal is sent to the engine control unit 33 to stop the engine control unit 33 from stopping. The electric motor 25 of the positive displacement compressor 21 is stopped by the signal.

(2) FIG. 4 shows a modified example of the check valve 22, which is provided with a plate-like valve body 41 so as to be rotatable, and the plate-like valve body 41 is seated on a valve seat 42. While preventing the backflow of the air supply from the mouth side, the plate-like valve body 41 can be pushed open only from the air supply upstream side to the air supply port side to circulate the air supply.

  As the opening degree detecting means for detecting the opening / closing state of the check valve 22 (opening / closing state of the bypass passage 11), an opening degree detecting means 44 for detecting the rotation amount (lift amount) of the plate-like valve body 41 is provided. If the rotation amount (lift amount) of the valve body 41 is equal to or greater than a predetermined value, it is determined that the check valve 22 is open, and the electric motor 25 of the positive displacement compressor 21 is stopped via the engine control unit 33. It has become.

(3) The check valve 22 in FIG. 5 has a structure including a rotating plate-like valve body 41 that is seated on the valve seat 42 as in FIG. As an opening degree detecting means for detecting the open / closed state of the bypass passage 11, an energization detecting means 47 is provided. Contact points 46a and 46b provided on the plate-like valve element 41 and the valve seat 42 are connected to the energization detecting means 47. The contact points 46a and 46b come into contact with each other when energized, and are energized. When the valve body 41 is open, the contacts 46a and 46b are separated from each other and are in a non-energized state.

  The energization detecting means 47 is connected to the engine control unit 33, and when the non-energized state is detected, it is determined that the check valve 22 is open, and the electric motor 25 of the positive displacement compressor 21 via the engine control unit 33. Is supposed to stop.

[Third Embodiment of the Invention]
(Constitution)
FIG. 6 shows a third embodiment of the present invention, which is an example applied to an internal combustion engine provided with an exhaust turbocharger 13 as in FIG. 1, but in comparison with the structure of FIG. The arrangement position of the cooling device 20 and the condition detection means when starting the operation of the positive displacement compressor 21 are different, and means for restricting the exhaust system is provided. Other structures are the same as those in FIG. 1, and the same parts and portions as those in FIG.

  The supply air cooling device 20 is disposed in the bypass passage 11 on the upstream side of the supply air from the check valve 22, and the supply air cooled by the supply air cooling device 20 flows while the positive displacement compressor 21 is operating. It is supposed not to.

  As condition detection means for starting the operation of the positive displacement compressor 21, an engine supply air temperature detection means 50 is provided in the supply air passage portion 10b on the supply air upstream side of the compression section 15 of the exhaust turbocharger 13, and Engine cooling water temperature detecting means 51 is provided in the cooling water jacket of the engine 1. Both temperature detecting means 50 and 51 are electrically connected to the engine control unit 33. An engine start command switch 48 is electrically connected to the engine control unit 33.

  The engine supply air temperature detecting means 50 detects the supply air temperature at the intake air inlet of the compression section 15 and if the supply air temperature is equal to or lower than a predetermined value, the engine control unit 33 is notified that “the supply air temperature is low. The “detection signal” is transmitted.

  The engine coolant temperature detection means 51 detects the engine coolant temperature, and transmits a “detection signal indicating that the coolant temperature is low” to the engine control unit 33 if the engine coolant temperature is below a predetermined value. It is like that.

  The electric motor 25 of the positive displacement compressor 21 confirms the start command by the engine start command switch 48, and then the supply air temperature or the cooling water temperature is detected by the engine supply air temperature detecting means 50 or the engine cooling water temperature detecting means 51. When it is detected that the value is equal to or less than a predetermined value, it is driven by a drive signal from the engine control unit 33. Further, when both the supply air temperature and the cooling water temperature become larger than a predetermined value, or when the supply air flow detecting means 31 detects the supply air flow state in the bypass passage 11 during operation of the electric motor, The operation is stopped by a stop signal from the control unit 33.

  An exhaust valve lift adjusting means 52 is provided as means for restricting the exhaust system, and the exhaust valve lift adjusting means 52 is electrically connected to the engine control unit 33. After confirming the start command by the start command switch 48 of the engine, when it is detected by the engine supply air temperature detecting means 50 or the engine cooling water temperature detecting means 51 that the supply air temperature or the cooling water temperature is not more than a predetermined value. The exhaust valve lift is reduced by a lift adjustment signal from the engine control unit 33.

(Operation and effect)
(1) The engine control unit 33 confirms the engine start command, and a detection signal indicating that the supply air temperature is equal to or lower than the predetermined value or the cooling water temperature is equal to or lower than the predetermined value is the supply air temperature detecting means 50 or the cooling water temperature. When input from the matter detection means 51, the electric motor 25 is driven by a drive signal from the engine control unit 33. Thereby, the positive displacement compressor 21 starts to rotate. The air heated by the pressure increase by the positive displacement compressor 21 is supplied to the air supply port 3 of the engine through the air supply passage portion 10a. At this time, the supply air pressure in the supply passage portion downstream of the positive displacement compressor 21 is higher than the internal pressure of the bypass passage 11 (pressure in the supply air upstream portion of the check valve 22). The stop valve 22 is closed. Therefore, the supply air does not pass through the supply air cooling device 20, and the supply air that is not cooled is supplied to the supply port 3.

  FIG. 13 shows a specific example of the increase in the supply air temperature by the positive displacement compressor 21. When the positive displacement compressor 21 having a pressure ratio of 1.4 and a compression efficiency of 55% is used, The temperature of the supply air at the engine supply port 3 is about 50 ° C., so that the supply air can be supplied to the engine even when the temperature is below freezing, and heating by a glow plug or the like becomes unnecessary.

  FIG. 14 shows changes in the in-cylinder air temperature and the in-cylinder air pressure with respect to the crank angle. The cases where the positive displacement compressor 21 is used are indicated by solid lines T1 and P1, respectively, and the positive displacement compressor 21 is used. The cases where there is no line are indicated by broken lines T0 and P0. At the compression top dead center (right-end crank angle 0 degree), the cylinder air temperature (T1) when the positive displacement compressor 21 is used is the cylinder internal air when the positive displacement compressor 21 is not used. The temperature rises by about 100 ° C compared to the temperature (T0), and the cylinder air pressure (P1) when the positive displacement compressor 21 is used is the same as that of the positive displacement compressor 21. Compared to the cylinder air pressure (P0) when there is no pressure, the pressure rises by about 1000 kPa or more. Due to the increase in the cylinder temperature and the cylinder pressure, the heat transfer coefficient increases by about 1.6 times, the heat input to the wall surface of the positive displacement compressor 21 increases, and the wall surface can be heated quickly.

(2) As described above, when the supply air temperature or the cooling water temperature in FIG. 6 becomes equal to or lower than the predetermined value and the electric motor 25 is driven, the exhaust valve lift adjusting means 52 is operated at the same time. Reduce lift. This increases the pumping loss during the exhaust stroke, keeps the cylinder pressure and temperature high, and quickly raises the cylinder wall temperature.

  More specifically, when the positive displacement compressor 21 of FIG. 6 is operated and air is pumped, the compression work (blower work) of the positive displacement compressor 21 becomes a part of the piston work in the cylinder, and at the time of idling. The fuel flow rate is reduced as compared with the case where the positive displacement compressor 21 is not provided, and the heating action of the cylinder wall surface is reduced. On the other hand, in order to heat the cylinder wall surface quickly, it is effective to prevent a decrease in the fuel flow rate during idling. As one countermeasure, as described above, by reducing the exhaust valve lift, It is possible to increase the residual amount of exhaust gas, increase the pumping loss in the exhaust stroke, keep the cylinder pressure and temperature high, increase the heat input to the cylinder wall surface, and increase the wall surface temperature more quickly.

(3) When a certain time has elapsed after the engine is started and the supply air temperature or the cooling water temperature exceeds a predetermined value, the positive displacement compressor 21 is stopped and the exhaust valve lift adjustment means 52 Return the lift to the original state and complete the cold start.

[Fourth Embodiment of the Invention]
FIG. 7 shows a fourth embodiment of the present invention. Compared with the structure of FIG. 6, as a means for restricting the exhaust system, a turbine portion of the exhaust turbocharger 13 is used instead of the exhaust valve lift adjusting means. An exhaust throttle valve 54 is provided at the inlet 14. The other structures are the same as those in FIG. 6, and the same parts and portions are denoted by the same reference numerals and detailed description thereof is omitted.

  The operation and effects are basically the same as those in FIG. 6 and will not be described in detail. However, when the electric motor 25 is driven when the supply air temperature or the cooling water temperature falls below a predetermined value, The throttle valve 54 is throttled, thereby increasing the pumping loss during the exhaust stroke, keeping the cylinder pressure and temperature high, and increasing the cylinder wall temperature quickly.

[Fifth Embodiment of the Invention]
FIG. 8 shows a fifth embodiment of the present invention, which is a modification of FIG. 6, and an exhaust throttle valve 55 is provided at the outlet of the turbine section 14 of the exhaust turbocharger 13 as means for restricting the exhaust system. ing. The other structures are the same as those in FIG. 6, and the same parts and portions are denoted by the same reference numerals and detailed description thereof is omitted.

[Other embodiments]
(1) As a means for detecting the operation start condition of the positive displacement compressor, an acceleration state detection means 30 as shown in FIG. 1 is provided, and the operation is started in the acceleration state, as shown in FIG. It is also possible to use a configuration in which means 50 and 51 for detecting the engine coolant temperature are provided and the operation is started when one of the temperatures is equal to or lower than a predetermined value. In this case, the throttle of the exhaust system is not operated.

(2) As means for detecting the operation start condition of the positive displacement compressor, instead of providing both means for detecting the engine supply air temperature and the engine cooling water temperature as shown in FIG. 6, only one temperature detection means is provided. A structure is also possible.

1 is a piping diagram of a first embodiment of a supercharging device for an internal combustion engine to which the present invention is applied. It is a piping diagram of 2nd Embodiment of the supercharging device of the internal combustion engine to which this invention is applied. It is an expanded sectional view of a check valve provided with differential pressure detection means. It is an expanded sectional view of the modification of a non-return valve and its opening degree detection means. It is an expanded sectional view of the modification of a non-return valve and its energization state detection means. It is a piping diagram of a 3rd embodiment of a supercharging device of an internal-combustion engine to which the present invention is applied. It is a piping diagram of a 4th embodiment of a supercharging device of an internal-combustion engine to which the present invention is applied. It is a piping diagram of a 5th embodiment of a supercharging device of an internal-combustion engine to which the present invention is applied. It is a figure which shows the relationship between the air flow rate in each of the compression part of a turbocharger, a positive displacement compressor, and the whole supercharging system, and a pressure ratio. It is a figure which shows the relationship between the rotational speed with respect to the electric current of the electric motor for positive displacement compressors, a voltage, and a torque. It is a figure which shows the relationship between the rotational speed of a positive displacement compressor, and a pressure ratio. It is a figure which shows the relationship between the air flow rate of the whole supercharging system, and a pressure ratio. It is a figure which shows the supply air temperature rise by a positive displacement compressor. It is a figure which shows the relationship between the air temperature in a cylinder and the air pressure in a cylinder with respect to a crank angle. It is a piping schematic diagram of a conventional example. It is a figure which shows the relationship between the air flow rate and pressure ratio of the compression part of the exhaust turbo supercharger of FIG. It is a piping schematic diagram of another conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Exhaust port 3 Supply port 4 Exhaust valve 5 Supply valve 6 Fuel injection nozzle part 8 Fuel supply passage 9 Throttle valve 10 Supply passage 10a Supply passage portion 11 Bypass passage 12 Exhaust passage 13 Exhaust turbo supercharger 14 Turbine part 15 Compression part 22 Check valve 26 Valve seat 27 Ball 30 Acceleration state detection means (throttle opening degree detection means)
Reference Signs List 31 Supply air flow detection means 33 Engine control unit 38 Differential pressure detection means 44 Check valve opening detection means 47 Check valve energization detection means 50 Engine supply air temperature detection means 51 Engine cooling water temperature detection means 52 Exhaust valve lift adjustment Means 54 Exhaust throttle valve (an example of exhaust throttle means)
55 Exhaust throttle valve (an example of exhaust throttle means)

Claims (16)

In the air supply passage, a positive displacement compressor driven by an electric motor is provided, and a bypass passage that bypasses the positive displacement compressor is provided,
In the bypass passage, a check valve for preventing a back flow of the supply air from the intake port side of the engine is arranged,
The check valve closes the bypass passage while the positive displacement compressor is operating and boosts the supply air. When the increase of the supply air by the positive displacement compressor stops, the check valve is opened. A supercharging device for an internal combustion engine, characterized in that the air can be supplied to an air supply port side of the engine. The supercharging device for an internal combustion engine according to claim 1,
Arrange the compression part of the exhaust turbocharger in the supply passage,
A supply air cooling device is disposed in the supply air passage portion on the downstream side of the supply air from the compression unit,
A supercharging device for an internal combustion engine, characterized in that the positive displacement compressor is disposed and a bypass passage having the check valve is provided in a supply air passage portion downstream of the air supply cooling device. The supercharging device for an internal combustion engine according to claim 1 or 2,
Acceleration state detection means for detecting the acceleration state of the engine rotation is provided,
A supercharging device for an internal combustion engine, wherein the positive displacement compressor is operated when an acceleration state is detected. The supercharging device for an internal combustion engine according to any one of claims 1 to 3,
The supercharging device for an internal combustion engine, wherein the check valve is a ball check valve in which a movable ball is seated on a valve seat. The supercharging device for an internal combustion engine according to any one of claims 1 to 3,
The check valve is a supercharging device for an internal combustion engine, which is a check valve in which a rotatable plate-like valve body is seated on a valve seat. The supercharging device for an internal combustion engine according to any one of claims 1 to 5,
A differential pressure detection means for detecting a differential pressure between the supply air upstream side and the supply air downstream side of the check valve is disposed in the bypass passage;
An internal combustion engine supercharging device configured to stop a positive displacement compressor when a detected differential pressure becomes a predetermined value or less while the positive displacement compressor is in operation. The supercharging device for an internal combustion engine according to claim 5,
An opening degree detecting means for detecting a check valve opening degree by the amount of rotation of the plate-like valve body is provided,
A supercharging device for an internal combustion engine configured to stop a positive displacement compressor when a check valve opening becomes a predetermined value or more during operation of the positive displacement compressor. The supercharging device for an internal combustion engine according to claim 5,
The valve seat and the plate-shaped valve body of the check valve are provided with a contact point that is energized when seated and de-energized when not seated, and is provided with a power-on detection means that detects the energization and de-energization,
A supercharging device for an internal combustion engine configured to stop a positive displacement compressor when a non-energized state is detected while the positive displacement compressor is operating. The supercharging device for an internal combustion engine according to any one of claims 1 to 8,
A supercharging device for an internal combustion engine, wherein an air capacity of the positive displacement compressor is smaller than a rated air amount of the internal combustion engine. The supercharging device for an internal combustion engine according to claim 1,
Arrange the compression part of the exhaust turbocharger in the supply passage,
The bypass compressor is provided in the supply passage portion on the downstream side of supply air from the compression section, and a bypass passage is provided to bypass the displacement compressor,
A supercharging device for an internal combustion engine, characterized in that a charge air cooling device is arranged in a bypass passage portion upstream of the check valve. The supercharging device for an internal combustion engine according to claim 10,
An engine supply air temperature detection means is provided,
A supercharging device for an internal combustion engine, wherein the positive displacement compressor is operated when an engine supply air temperature is equal to or lower than a predetermined value. The supercharging device for an internal combustion engine according to claim 10,
Provide engine coolant temperature detection means,
A supercharging device for an internal combustion engine, wherein a positive displacement compressor is operated when an engine coolant temperature is below a predetermined value. The supercharging device for an internal combustion engine according to claim 11 or 12,
Exhaust valve lift adjustment means is provided,
A supercharging device for an internal combustion engine, characterized in that the exhaust valve lift is made small when the engine supply air temperature or the engine coolant temperature is below a predetermined value. The supercharging device for an internal combustion engine according to claim 11 or 12,
Exhaust valve opening / closing timing adjustment means is provided,
A supercharging device for an internal combustion engine, characterized in that the exhaust valve opening timing is delayed when the engine supply air temperature or the engine coolant temperature is below a predetermined value. The supercharging device for an internal combustion engine according to claim 11 or 12,
The exhaust turbocharger has a variable turbine capacity,
A turbocharger for an internal combustion engine, characterized in that a turbine capacity of an exhaust turbocharger is reduced when an engine supply air temperature or an engine coolant temperature is equal to or lower than a predetermined value. The supercharging device for an internal combustion engine according to claim 11 or 12,
In the turbine portion of the exhaust turbocharger, a throttle means for making the exhaust outlet cross-sectional area variable is provided,
A supercharging device for an internal combustion engine, characterized in that an exhaust outlet sectional area is throttled by the throttle means when an engine supply air temperature or an engine cooling water temperature is a predetermined value or less.

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