JP2006214273A - Supercharger of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of knocking by restraining a rise of intake temperature when the operating condition of an engine is within a pre-rotation region in a supercharger of the engine. <P>SOLUTION: This supercharger of an engine includes: a motor-driven supercharger provided in an intake passage; a by-pass passage for communicating the upstream and the downstream of the motor-driven supercharger with each other in the intake passage; a by-pass valve opening and closing the by-pass passage; and an intake system controller for controlling the rotational frequency of the motor-driven supercharger and the by-pass valve to obtain a predetermined supercharging pressure when the operating condition of the engine is in the supercharging region. When the operating condition of the engine is determined to be within the pre-rotation region, the intake system controller controls the rotational frequency of the motor-driven supercharger and the by-pass valve to obtain lower supercharging pressure than that when the operating condition is within the supercharging region, performs the cylinder cut-off operation to stop the fuel supply to a specified cylinder, and circulates the fresh air discharged from the cylinder where the supply of fuel is stopped to an intake passage on the upstream side of the motor-driven supercharger. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of an engine supercharging device that increases engine torque by supercharging.

  Conventionally, superchargers and turbochargers that supercharge intake air as means for increasing engine torque are well known. However, as a result of the supercharging ability being greatly affected by the engine speed, the supercharging pressure is low. There is a drawback of lacking. On the other hand, the electrically driven electric supercharger can control the rotational speed without being affected by the engine rotational speed, and therefore has an advantage that a sufficient supercharging pressure can be generated even in a low rotational speed region.

  For example, an engine supercharger described in Patent Document 1 is provided on an electric supercharger disposed on an intake passage, a bypass passage communicating with the upstream side of the supercharger, and a bypass passage. When the engine operating state is in the supercharging region, supercharging is performed by operating the supercharger and closing the bypass valve. In the engine supercharging device having such a configuration, pre-rotation control has been proposed as a method for further improving the responsiveness at the time of rapid acceleration or the like.

As this pre-rotation control, for example, the electric supercharger is operated with the bypass valve opened in advance before the engine operating state shifts to the supercharging region, and the number of rotations of the electric supercharger is increased in advance. Therefore, there is a rotation control that allows a required supercharging pressure to be quickly obtained when the supercharging region is entered. In addition, by operating the electric supercharger in a state where the bypass valve is closed and made clear before the operating state of the engine shifts to the supercharging region, the pressure on the downstream side of the electric supercharger is increased in advance. There is a preload control that allows a required supercharging pressure to be obtained quickly when shifting to a region.
JP 2003-227342 A

  However, the intake air temperature rises during the pre-rotation control, and there is a problem that high-temperature intake air is introduced into the combustion chamber and knocking is likely to occur. The cause for increasing the intake air temperature during the pre-rotation control is as follows, for example.

  That is, at the time of rotation control, since the electric supercharger is operated with the bypass valve opened, the intake air is circulated through the bypass passage, and this circulation is caused by the operation of the electric supercharger. The temperature gradually rises as it repeatedly receives heat.

  Further, at the time of preload control, the pressure difference before and after the bypass valve which is set to be closed causes the intake air temperature to rise. That is, by this pressure difference, the potential energy of the high intake air downstream of the electric supercharger is converted into kinetic energy as a flow velocity when flowing upstream of the turbocharger through the clearance of the bypass valve, and this kinetic energy is When the flow velocity is lost due to, for example, a collision with fresh air upstream of the supercharger, it is converted into thermal energy, which increases the intake air temperature.

  Accordingly, an object of the present invention is to suppress an increase in intake air temperature and prevent occurrence of knocking when an engine operating state is in a pre-rotation region in an engine supercharging device.

  In order to solve the above problems, the present invention is configured as follows.

  First, the invention according to claim 1 of the present application is directed to an electric supercharger provided in an intake passage, a bypass passage communicating with the downstream side of the electric supercharger in the intake passage, and opening and closing the bypass passage. And a supercharging control means for controlling the rotational speed of the electric supercharger and the bypass valve so that a predetermined supercharging pressure is obtained when the operating state of the engine is in the supercharging region. And determining means for determining whether or not the engine operating state is in a pre-rotation region set on the low load side of the supercharging region, and the engine operating state is preliminarily determined by the determining unit. Pre-rotation control means for controlling the rotational speed of the electric supercharger and the bypass valve so that the supercharging pressure is lower than that in the supercharging region when it is determined that the operation state is in the supercharging region; During pre-rotation control by the rotation control means, Reduction operation means for stopping fuel supply to the engine, and recirculation means for recirculating fresh air discharged from the cylinder whose fuel supply has been stopped to the intake passage upstream of the electric supercharger during reduction operation by the reduction cylinder operation means It is characterized by having.

  Of the pre-rotation control, in the pre-pressure control, the rotation speed and bypass valve of the electric supercharger are controlled so that a supercharging pressure lower than the supercharging pressure in the supercharging region is obtained. Then, although the preload is not performed, the rotational speed of the electric supercharger is controlled so that the supercharging pressure immediately downstream of the electric supercharger is lower than the supercharging pressure in the supercharging region.

  According to a second aspect of the present invention, in the engine supercharging device according to the first aspect of the present invention, the throttle opening correction means for increasing the throttle opening is reduced during the reduced cylinder operation by the reduced cylinder operating means. It is characterized by having.

  According to a third aspect of the present invention, in the engine supercharging device according to the first aspect of the present invention, the engine has an intake air temperature detecting means for detecting an intake air temperature downstream of the electric supercharger, and the intake air temperature detecting means The reduced-cylinder operating means and the reflux means are operated only when the detected intake air temperature is equal to or higher than a predetermined value.

  First, according to the first aspect of the present invention, since the fuel supply to the specific cylinder is stopped during the pre-rotation control, fresh air is discharged from the specific cylinder. This fresh air is then returned to the intake passage upstream of the electric supercharger.

  In this case, when the air taken into the specific cylinder is heated in the compression process, heat is absorbed by the cooling water around the combustion chamber, and the temperature further decreases in the subsequent expansion stroke. It becomes lower than the temperature (atmospheric temperature) at the time. Then, since this low-temperature air is returned to the intake passage upstream of the electric supercharger, the intake air temperature is lowered or suppressed as a whole during the pre-rotation control. Is prevented from occurring.

  According to the second aspect of the present invention, since the throttle opening is increased during the reduced-cylinder operation, the amount of air introduced into each cylinder is increased and the output of the combustion cylinder is increased. As a result, it is possible to avoid a decrease in the output of the engine as a whole despite the reduction in the number of cylinders.

  At this time, by increasing the throttle opening, the pumping loss is reduced and the fuel efficiency is improved. For example, during a pre-rotation control with a 2-liter gasoline engine that performs pre-rotation at 2500 rpm or less, the rated power of the electric supercharger is 2 kW, and the rated power of the alternator is 2 kW, In order to recover the power consumed by the alternator by power generation of the alternator, it is inevitable that the fuel consumption is reduced by around 8%, but this is offset by the fuel efficiency improvement effect of 7 to 11% due to the reduction of the pumping loss. The deterioration of fuel consumption is prevented.

  According to the third aspect of the present invention, when the intake air temperature is less than the predetermined value, knocking is unlikely to occur. Therefore, reduction in engine output is avoided without performing reduced-cylinder operation, and intake air When the temperature is equal to or higher than the predetermined value, knocking is likely to occur. Therefore, the reduced-cylinder operation is performed to suppress an increase in the intake air temperature, thereby preventing the occurrence of knocking.

  Hereinafter, embodiments of the present invention will be described.

  First, a first embodiment of the present invention will be described. FIG. 1 shows an intake system 1 and an exhaust system 2 of an engine according to the present embodiment.

  In the intake system 1, an air cleaner 11, an electric supercharger 12, a throttle valve 13, and a surge tank 14 are provided in the intake passage 10 from the upstream side, and communicate from the surge tank 14 to the respective cylinders # 1 to # 4. A plurality of independent intake passages 15... 15 are branched.

  In addition, a bypass passage 16 that directly communicates the upstream and downstream sides of the electric supercharger 12 in the intake passage 10 is provided, and a bypass valve that controls the flow rate of air passing through the passage 16 is provided in the bypass passage 16. 17 is provided.

  The electric supercharger 12 includes a compressor 12a and a motor 12b. When the motor 12b is driven, the compressor 12a sucks air and pumps it to the cylinders # 1 to # 4. Increase torque.

  On the other hand, the exhaust system 2 has a plurality of independent exhaust passages 21a... 21d extending from the cylinders # 1 to # 4 and independent exhaust passages 21a and 21d extending from the first and fourth cylinders # 1 and # 4 on the downstream side. A first merged exhaust passage 22a formed by merging at the downstream side of the first and second independent exhaust passages 21b and 21c extending from the second and third cylinders # 2 and # 3; It has a collective exhaust passage 23 formed by joining the second joining passages 22a and 22b on the downstream side.

  A communication passage 30 is provided which branches from the first combined exhaust passage 22 a and communicates with the exhaust passage 10 upstream of the electric supercharger 12. Air passing through the passage 30 is provided on the communication passage 30. A circulation valve 31 is provided to control the flow rate.

  The engine control apparatus 100 for controlling the engine receives a signal from an accelerator opening sensor 40 that detects the amount of depression of the accelerator pedal 40a (engine load) by the driver, and an engine speed sensor 41 that detects the engine speed. , A signal from the intake air temperature sensor 42 for detecting the intake air temperature, and the like are input.

  The engine control apparatus 100 performs various controls on the spark plugs 43... 43, the fuel injection valves 44a... 44d, the intake system controller 101, and the like provided in the cylinders # 1 to # 4 based on those input signals. Output a signal. The intake system controller 101 controls the rotational speed of the throttle actuator 45 that opens and closes the throttle valve 13, the bypass actuator 46 that opens and closes the bypass valve 17, the circulation valve 31, and the motor 12 b of the electric supercharger 12. A control signal is output to the feeder controller 102 or the like.

  Further, the engine includes an alternator 50 that generates electric power by driving the engine, and a battery 51 that stores electric power generated by the alternator 50. Electric power is supplied from the battery 51 to the electric supercharger controller 102. It comes to be supplied.

  The intake passage 10, the electric supercharger 12, the bypass passage 16, and the bypass valve 17 correspond to the constituent elements that are the premise of the supercharging device according to claim 1. The engine control device 100 corresponds to a determination unit and a reduced-cylinder operation unit in the supercharging device according to claim 1, and an intake system controller 101 corresponds to the supercharging control device and the precharge in the supercharging device according to claim 1. The communication passage 30, the circulation valve 31, and the intake system controller 101 correspond to a rotation control unit, and correspond to a reflux unit in the supercharging device according to claim 1. Further, the intake system controller 101 corresponds to throttle opening correction means in the supercharging device according to claim 2, and the intake air temperature sensor 42 corresponds to intake air temperature detection means in the supercharging device according to claim 3. .

  On the other hand, the engine control device 100 stores a map in which the engine operating region shown in FIG. 2 is set. In this map, four areas with the engine speed and the engine load as parameters are set. In other words, the natural intake region is on the high rotation side (engine speed is N1 or higher) of the entire engine operation region, and the prerotation region (preload) is on the low load low rotation side (engine speed is N1 or lower and engine load is α1 or lower). Area), a supercharging area is set on the high load low rotation side (engine speed is N1 or less, engine load is α1 or more), and a surging area is set on the low rotation side in the supercharging area. ing.

  In the natural intake region, control is performed so that the electric supercharger 12 is not operated with the bypass valve 17 open. Then, the air introduced into the intake passage 10 flows through the bypass passage 16 in the forward direction as indicated by an arrow A in FIG. 1 and is supplied to the cylinders # 1 to # 4. In this region, the normal four-cylinder operation is performed and the circulation valve 31 is closed so that fresh air exhausted from the first and fourth cylinders # 1 and # 4 is not recirculated to the intake passage 10. Is done.

  In the pre-rotation region, pre-load control is performed in the present embodiment. In the preload control, the electric supercharger 12 is controlled to operate in a state where the bypass valve 17 is closed. As a result, the pressure on the downstream side of the electric supercharger 12 in the intake passage 10 is increased in advance, and the responsiveness improvement of the supercharging pressure is realized when the engine operating state shifts to the supercharging region. . At this time, throttle control of the throttle valve 13 is performed at the same time so that the intake air amount introduced into the cylinders # 1 to # 4 is not increased more than necessary, and the intake air amount is accurately realized.

  In this region, when the intake air temperature is equal to or higher than a predetermined value, the reduced cylinder control for stopping the fuel supply of the fuel injection valves 44a and 44d for supplying fuel to the first and fourth cylinders # 1 and # 4 is performed. At the same time, the opening degree of the throttle valve 13 is controlled to be increased. At this time, the circulation valve 31 is controlled to open, and as shown by the arrow D in FIG. 1, the fresh air discharged from the first and fourth cylinders # 1 and # 4 is electrically supercharged via the communication passage 30. The air is recirculated to the intake passage 10 upstream of the machine 12.

  When the intake air temperature is equal to or lower than the predetermined value, normal four-cylinder operation is performed and the circulation valve 31 is controlled to be closed, so that fresh air is not recirculated.

  In the supercharging region, the electric supercharger 12 is controlled to operate with the bypass valve 17 closed. At this time, the air introduced from the air cleaner 11 into the intake passage 10 flows through the intake passage 10 as shown by an arrow B in FIG. In this region, normal four-cylinder operation is performed, and the circulation valve 31 is controlled to be closed, so that fresh air is not recirculated.

  In the surging region, the electric supercharger 12 is operated with the bypass valve 17 half open. This surging region is a region where the pressure on the downstream side of the electric supercharger 12 is high, the flow rate of the intake air is reduced, and the intake air may flow back through the electric supercharger 12. Here, the bypass valve 17 As shown by the arrow C in FIG. 1, a part of the intake air is circulated in the bypass passage 16 in the reverse direction. In this region, normal four-cylinder operation is performed, and the circulation valve 31 is controlled to be closed, so that fresh air is not recirculated.

  On the other hand, the map of FIG. 3 shows the characteristics of the electric supercharger 12. In this map, the pressure ratio on the upstream and downstream sides of the electric supercharger 12 is plotted on the vertical axis with the intake air amount on the horizontal axis. Is shown in And the area | region X shown to a figure is set as a use area | region of this electric supercharger 12. FIG. The region Y on the low intake air amount / high pressure ratio side of the region X is a region where the above-mentioned surging is likely to occur because the pressure on the downstream side of the electric supercharger 12 is high and the air flow rate is small.

  Further, in the area X, areas a to p corresponding to the power consumption of the electric supercharger 12 are set. These areas a to p are substantially strip-shaped areas divided by a plurality of curves in which the pressure ratio decreases as the intake air amount increases, and the region a on the low intake air amount / low pressure ratio side The power consumption increases in order.

  Further, in region X, the rotational speed characteristics of the electric supercharger 12 are shown. As for this characteristic, a curve of a rotational speed of 40000 rpm is set on the low intake air amount / low pressure ratio side of the region X, and it is shown that the rotational speed increases as it moves to the high intake air amount / high pressure ratio side.

  By the way, the rated power of the electric supercharger 12 used in the present embodiment is 2 kW, and when the power consumption of the electric supercharger 12 exceeds 1 kW, which is half of the rated power, the discharge pressure increases accordingly. It has been found that knocking is likely to occur. As shown in FIG. 4, since the ignition timing retard control is performed to suppress this knocking, the actually obtained engine torque is moderately increased. Further, since the torque consumed by the alternator 50 increases according to the power consumption of the electric supercharger 12, the actually obtained engine torque is further suppressed. As a result, in the region where the power consumption of the supercharger 12 is 1 kW or more Even if the power consumption of the supercharger 12 is further increased, the net actual torque hardly increases. Here, the electric power consumption of the electric supercharger 12 when knocking is likely to occur is 1 kW, but this value is changed according to the rating and characteristics of the electric supercharger 12.

  The intake system 1, the exhaust system 2, and the circulation valve 31 are controlled by the engine control device 100, the intake system controller 101, and the electric supercharger controller 102 according to the flowchart shown in FIG. 5.

  First, in step S1, the engine control apparatus 100 reads various signals from each sensor, and in step S2, the intake air amount is obtained based on these signals. Specifically, the intake air amount is calculated based on the engine load detected by the accelerator opening sensor 40 and the engine speed detected by the engine speed sensor 41. At this time, the intake air amount may be detected by a sensor or the like.

  Then, in step S3, it is determined whether or not the engine speed is greater than N1, and if it is greater than N1, the operating state belongs to the natural intake region shown in the map of FIG. 2, and therefore the bypass valve 17 is fully opened in step S4. In step S5, the operation of the electric supercharger 12 is stopped. Further, a 4-cylinder operation is executed in step S6, and the circulation valve 31 is controlled to be closed in step S7. Thereby, the recirculation of the air from the communication passage 30 is stopped, and the natural intake in which the air introduced from the air cleaner 11 is supplied to the cylinders # 1 to # 4 via the bypass passage 16 is executed.

  On the other hand, when the engine speed is N1 or less in step S3, the process proceeds to step S8 to determine whether or not the engine load is greater than α1. When the engine load is larger than α1, the engine operating state belongs to the supercharging region. At this time, it is further determined in step S9 whether or not the operating state belongs to the surging region.

  When the engine operating state does not belong to the surging region in step S9, the process proceeds to step S10, the bypass valve 17 is closed, and 1 kW operation control is performed in step S11. In this 1 kW operation control, the electric intake air quantity obtained in step S2 is obtained on the area h corresponding to 1 kW among the areas a to p corresponding to the power consumption of the electric supercharger 12 shown in FIG. The rotational speed of the supercharger 12 is read, and the rotational speed of the supercharger 12 is controlled to this rotational speed.

For example, in the 1 kW operation control when the intake air amount obtained in step S2 is 2 m ³ / min, the rotation speed of the electric supercharger 12 at the point Z on the region h is read in the map of FIG. The point Z is at a position where the rotational speed is slightly closer to 60000 rpm from 60000 rpm, and 62000 rpm is obtained by interpolation. Then, the engine control device 100 sends a signal to the intake system controller 101, and controls the supercharger 12 to have this rotational speed via the electric supercharger controller 102, whereby the power consumption is 1 kW and the rotational speed. The operation at 62000 rpm is realized.

  After this 1 kW operation control, the process proceeds to step S12 to execute a four-cylinder operation, and control is performed so that the circulation valve 31 is closed in step S13.

  On the other hand, when the engine operating state belongs to the surging region in step S9, the process proceeds to step S14, the bypass valve 17 is controlled to be half open, the aforementioned 1 kW operation control is performed in step S15, and the process proceeds to step S12. As a result, a part of the air discharged from the electric supercharger 12 flows back through the bypass passage 16, and as a result, the pressure downstream of the supercharger 12 is lowered and the occurrence of surging is avoided in advance. .

Further, since a part of the air is circulated through the bypass passage 16 in this way, the amount of air actually sucked is smaller than that required. On the other hand, if the amount of air circulating through the bypass passage 16 is β, it is assumed that an intake air amount increased by an amount corresponding to β is required in order to supplement the air amount β during 1 kW operation control. Will apply the map. For example, when the intake air amount calculated in step S1 is 2 m ³ / min, 2 + βm ³ / min obtained by adding the amount of air to be circulated 2 + βm ³ / min is set as the value of the intake air amount and the region h corresponding to this intake air amount The rotational speed (about 58000 rpm) at the point Z ′ is read out.

  By the way, when it is determined in step S8 that the engine load is equal to or less than α1, since the operating state belongs to the pre-rotation region (pre-load region), pre-pressure control is performed in steps S16 to S22. First, in step S16, the bypass valve 17 is controlled to be substantially closed, and in step S17, the rotation speed of the electric supercharger 12 is controlled to a preset rotation speed for preload control. Note that the rotational speed of the electric supercharger 12 for preload control is set to be lower than the rotational speed in the supercharging region, for example, and the obtained supercharging pressure is also lowered.

  Next, in step S18, it is determined whether or not the intake air temperature detected by the intake air temperature sensor 42 is higher than T1. If the intake air temperature is higher than T1, the reduced-cylinder operation is executed in step S19. In this reduced-cylinder operation, the fuel injection valves 44a and 44d are controlled so as to stop the fuel supply to the first and fourth cylinders # 1 and # 4. At this time, since the number of cylinders contributing to the output is reduced by the reduced cylinder, the output of the engine is reduced. However, the opening of the throttle valve 13 is increased so that the cylinders # 1 to # 4 are supplied. The amount of introduced air is increased, thereby increasing the outputs of the combustion cylinders # 2 and # 3, thereby avoiding a decrease in the output of the entire engine. Further, in step S20, control is performed so that the circulation valve 31 is opened.

  As a result of such reduced-cylinder operation, fresh air discharged from the first and fourth cylinders # 1 and # 4 reaches the first merging passage 22a through the independent exhaust passages 21a and 21d, and is further electrically driven through the communication passage. The refrigerant is returned to the intake passage 10 upstream of the supercharger 12.

  On the other hand, when the intake air temperature is equal to or lower than T1 in step S18, the process proceeds to step S21 to execute the four-cylinder operation, and control is performed so that the circulation valve 31 is opened in step S22.

  Steps S19 and 20 correspond to the gist of the invention described in claims 1 and 2, and steps S18 to S21 correspond to the gist of the invention described in claim 3.

  Next, as a second embodiment of the present invention, a case where each operation region is set as shown in the map of FIG. 6 will be described. This map is obtained by changing the pre-rotation region set in the low-load low-rotation region of the map of FIG. 2 from the pre-load region to the rotation region.

  The rotation control performed in the pre-rotation region is performed when the electric supercharger 12 is operated with the bypass valve 17 opened and air is circulated through the bypass passage 16 so that the operation state is shifted to the supercharge region. Improves the supercharging pressure response. In this rotation region, since the bypass valve 17 is opened, no preload is performed. However, the supercharging pressure immediately downstream of the electric supercharger 12 is the supercharging pressure in the supercharging region. It is set to be smaller.

  In this embodiment, control is performed according to the flowchart shown in FIG. In this flowchart, steps S31 to S45 are the same controls as steps S18 to S22 in steps S1 to S15 and steps S48 to S52 in the flowchart shown in FIG. 5 in the first embodiment. Will be omitted, and only steps S46 and S47 related to rotation control will be described here.

  That is, after it is determined that the operating state of the engine belongs to the pre-rotation region, the bypass valve is controlled to be fully opened in step S46, and in step S47, the rotational speed of the electric supercharger 12 is set to the rotational speed for rotational control. Control.

  As described above, since the fuel supply to the first and fourth cylinders # 1 and # 4 is stopped during the pre-rotation control, fresh air is discharged from the cylinders # 1 and # 4. Become. Then, the fresh air is returned to the intake passage 10 upstream of the electric supercharger 12.

  In this case, when the air sucked into the first and fourth cylinders # 1 and # 4 is heated in the compression process, the heat is absorbed by the cooling water around the combustion chamber and the subsequent expansion stroke is performed. Since the temperature further decreases, the temperature becomes lower than the temperature when it is inhaled (atmospheric temperature). Since this low-temperature air is recirculated to the intake passage 10 upstream of the electric supercharger 12, the intake air temperature is lowered or suppressed as a whole during the pre-rotation control. This prevents knocking from occurring.

  In addition, since the opening of the throttle valve 13 is increased during the reduced-cylinder operation, the amount of air introduced into each of the cylinders # 1 to # 4 increases, and the second and third cylinders # 2 and # 3 (combustion cylinders) Output increases. As a result, it is possible to avoid a decrease in the output of the engine as a whole despite the reduction in the number of cylinders.

  At this time, by increasing the opening of the throttle valve 13, the pumping loss is reduced and the fuel efficiency is improved. For example, in a gasoline engine with a displacement of 2 liters, pre-rotation is performed at 2500 rpm or less, the rated power of the electric supercharger 12 is 2 kW, and the rated power of the alternator 50 is 2 kW. In order to recover the power consumed by the feeder 12 by the power generation of the alternator 50, the fuel consumption is reduced by about 8%, but this is offset by the fuel efficiency improvement effect of 7 to 11% due to the reduction of the pumping loss, and the pre-rotation control Deterioration of fuel consumption due to performing is prevented.

  When the intake air temperature is less than the predetermined value, knocking is unlikely to occur, so reduction in engine output is avoided without performing the reduced-cylinder operation, and when the intake air temperature is higher than the predetermined value, knocking does not occur. Since this is an easy-to-occur state, the reduced-cylinder operation is performed to suppress an increase in the intake air temperature, thereby preventing knocking.

  An object of the present invention is to suppress an increase in intake air temperature and prevent knocking when an engine operating state is in a pre-rotation region in an engine supercharging device. INDUSTRIAL APPLICABILITY The present invention is widely suitable for the technical field of an engine supercharging device that increases engine torque by supercharging.

1 is a system diagram of an engine according to an embodiment of the present invention. It is a map which shows the driving | operation area | region of an engine. It is a map which shows the characteristic of an electric supercharger. It is a graph which shows the engine torque characteristic according to the power consumption of an electric supercharger. It is a flowchart which concerns on control of an engine. It is a map which shows the driving | operation area | region of the engine which concerns on the 2nd Embodiment of this invention. It is a flowchart concerning control of the engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Intake passage 12 Electric supercharger 16 Bypass passage 17 Bypass valve 30 Communication passage 31 Circulation valve 42 Intake temperature sensor 100 Engine control device 101 Intake system controller # 1- # 4 cylinder

Claims (3)

An electric supercharger provided in the intake passage, a bypass passage communicating the upstream side and the downstream side of the electric supercharger in the intake passage, a bypass valve that opens and closes the bypass passage, and an engine operating state is a supercharging region And a supercharging control means for controlling the rotational speed of the electric supercharger and the bypass valve so that a predetermined supercharging pressure is obtained when
Determination means for determining whether or not the operating state of the engine is in a pre-rotation region set on the low load side of the supercharging region;
When it is determined by the determination means that the engine operating state is in the pre-rotation region, the rotational speed of the electric supercharger and the bypass valve are set so that the supercharging pressure is lower than when the operating state is in the supercharging region. Pre-rotation control means for controlling;
Reduced-cylinder operation means for stopping fuel supply to a specific cylinder during the pre-rotation control by the pre-rotation control means;
The engine supercharging further comprises recirculation means for recirculating fresh air exhausted from the cylinder whose fuel supply has been stopped to the intake passage upstream of the electric supercharger during the reduced cylinder operation by the reduced cylinder operation means. apparatus. The engine supercharging device according to claim 1,
An engine supercharging device comprising throttle opening correcting means for increasing the throttle opening during reduced cylinder operation by the reduced cylinder operating means. The engine supercharging device according to claim 1,
An intake air temperature detecting means for detecting the intake air temperature downstream of the electric supercharger;
An engine supercharging device, wherein the reduced-cylinder operating means and the reflux means are operated only when the intake air temperature detected by the intake air temperature detecting means is equal to or higher than a predetermined value.

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