JP4487800B2 - Engine supercharger - Google Patents

Description

  The present invention belongs to a technical field related to an engine supercharging device configured to supercharge intake air to an engine by rotational driving of an electric supercharger disposed in an intake passage.

  Conventionally, for example, as disclosed in Patent Document 1, instead of an exhaust gas turbocharger that uses exhaust gas energy, an engine that uses an electric supercharger to supercharge intake air is known. It has been. An electric supercharger that is disposed in an intake passage and supercharges intake air to the engine by electric rotation driving, a bypass passage provided to bypass the electric supercharger, and the bypass passage And a throttle valve disposed downstream of the bypass passage connecting portion on the downstream side of the electric supercharger of the intake passage, and the electric supercharger. During the operation of the engine, the bypass passage is closed by the bypass valve and the intake air is supplied to the engine via the electric supercharger. While the operation of the electric supercharger is stopped, the bypass passage is opened and the intake air is bypassed. The engine is supplied via.

For example, as shown in Patent Document 2, an electric supercharger that assists in driving an exhaust gas turbocharger is also known. And in this patent document 2, the response characteristic of the exhaust gas turbocharger is improved by rotating the electric supercharger in advance during the engine operation state directly preceding the increase in the driver's desired torque. Yes.
Japanese Patent Laid-Open No. 10-1559577 JP 2003-227342 A

  By the way, when supercharging is performed using an electric supercharger as in Patent Document 1, when the electric supercharger is changed from an operation stop state to an operation state, the electric supercharger has a necessary rotation speed. Takes time, and there is a problem that the response of the electric supercharger is poor. Therefore, similarly to Patent Document 2, a supercharging region and a pre-rotation region are provided as the engine operating state, and the engine operating state is predicted. It is conceivable to drive the electric supercharger in advance when in the rotation region. In this case, during the pre-rotation of the electric supercharger, if the bypass valve is in a fully open state and the throttle valve is in a fully closed state, a large amount of air whose pressure has been increased by the rotation of the electric supercharger. The portion circulates so as to flow to the upstream side of the intake passage through the bypass passage and return to the electric supercharger again, and the flow rate of air supplied to the engine through the throttle valve is reduced. If the bypass valve is closed and the throttle valve is opened in the supercharging region, the intake air compressed by the electric supercharger can be quickly supplied to the engine. . As described above, when the engine operating state is in the pre-rotation region, each opening degree of the bypass valve and the throttle valve and the drive rotational speed or current of the electric supercharger are controlled as in the supercharging region. If so, it will be possible to quickly shift from the pre-rotation region to the supercharging region.

  However, when the engine operating state is in the pre-rotation region, it is a problem how to actually rotate the electric supercharger. Of course, it is possible to quickly shift from the pre-rotation region to the supercharging region. That is, it is required to keep the power consumption of the supercharger drive small.

  The present invention has been made in view of such a point, and the object of the present invention is to quickly move from the pre-rotation region to the super-charging region when the electric supercharger is pre-rotated as described above. It is to make it possible to shift and to suppress the power consumption of the supercharger drive as small as possible.

  In order to achieve the above object, according to the first aspect of the present invention, an electric supercharger which is disposed in an intake passage of an engine and supercharges intake air to the engine by electric rotation driving, and the electric supercharger A bypass passage provided to bypass the bypass passage, a bypass valve disposed in the bypass passage, and a throttle disposed downstream of the bypass passage connection portion on the downstream side of the electric supercharger of the intake passage The bypass valve and the throttle valve so that the electric supercharger is rotationally driven at a predetermined driving power or less when the valve and the operating state of the engine are in a supercharging region set to a predetermined high load side. And a pre-rotation region in which the operating state of the engine is set adjacent to the low load side of the supercharging region. When you are on When the engine operating state is in the pre-rotation region, the pre-rotation control unit is intended for an engine supercharging device including pre-rotation control means for rotating the electric supercharger in advance. The driving speed or current of the electric supercharger is calculated when the engine is rotating at the same engine speed as the current engine speed in the pre-rotation area in the supercharging area. The control of the supply control means controls the discharge speed of the electric supercharger so that it becomes the same drive rotation speed or current as when the pressure becomes the predetermined pressure, and the air flow rate of the discharge section By controlling the supercharging control means, the opening degree of the bypass valve and the throttle valve is controlled so as to be smaller than the air flow rate of the discharge part when the pressure of the discharge part becomes a predetermined pressure. Configuration was.

  With the above configuration, when the engine operating state is in the supercharging region, the degree of opening of each of the bypass valve and the throttle valve and the electric motor are controlled by the supercharging control means so that the electric supercharger is driven at a predetermined driving power or less. The driving speed or current of the supercharger is controlled. On the other hand, when the operating state of the engine is in the pre-rotation region, the pre-rotation control means controls the opening degree of the bypass valve and the throttle valve and the drive rotational speed or current of the electric supercharger. In this pre-rotation area, the drive speed or current of the electric supercharger is assumed to be the same as the current engine speed in the pre-rotation area. In the above, the control of the supercharging control means has the same driving rotational speed or current as when the pressure (discharge pressure) of the discharge portion of the electric supercharger becomes a predetermined pressure. Thus, the predetermined pressure is a pressure within a pressure range that can be generated in the discharge portion of the electric supercharger according to the control result of the supercharging control means at the engine speed, and the pre-rotation range is maintained when the engine speed is constant. If the transition to the supercharging region, the driving rotational speed or current of the electric supercharger in the pre-rotation region is the driving rotational speed of the electric supercharger when controlled by the supercharging control means in the supercharging region or There is no significant difference with respect to the current, and the change in the driving speed or current of the electric supercharger associated with the transition can be small. As a result, it becomes possible to quickly shift from the pre-rotation region to the supercharging region. Normally, the engine speed increases to the supercharging area while the engine speed increases. At this time, if the drive speed or current of the electric supercharger is changed in accordance with the increase of the engine speed, The change in the driving speed or current can sufficiently follow the increase in the engine speed, and the response hardly decreases.

  Further, in the pre-rotation region, the air flow rate at the discharge unit of the electric supercharger is smaller than the air flow rate at the discharge unit when the pressure of the discharge unit becomes a predetermined pressure in the supercharge region. The drive power of the machine can be small, so that the power consumption of the turbocharger drive can be kept small.

  According to a second aspect of the present invention, in the first aspect of the invention, the pre-rotation control means sets the air flow rate of the discharge portion of the electric supercharger to a minimum air flow rate at which surging does not occur in the electric supercharger or its It is assumed that each opening degree of the bypass valve and the throttle valve is controlled so as to be in the vicinity.

  By doing so, the driving power of the electric supercharger can be reduced to the maximum within the range where surging does not occur in the electric supercharger, and the power consumption of the supercharger drive can be suppressed as small as possible.

  According to a third aspect of the invention, in the first or second aspect of the invention, the predetermined drive power is lower than a rated drive power of the electric supercharger and is a maximum drive power that does not cause knocking in the engine. To do.

  Thus, since supercharging is performed in a range where knocking does not occur in the engine, supercharging can be performed effectively, and power consumption for driving the supercharger can be suppressed even in the supercharging region.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the alternator driven by the engine is provided, and the predetermined drive power is an output corresponding to the maximum power generation amount of the alternator.

  As a result, it is possible to cover the driving power of the electric supercharger with the amount of power generated by the alternator, and to suppress the carry-out of power from the battery. Therefore, the electric supercharger can be appropriately driven while maintaining the balance between the power generation amount of the alternator and the power consumption of the supercharger drive.

  As described above, according to the supercharging device for an engine of the present invention, when the operating state of the engine is in the pre-rotation region, the engine rotation speed or current of the electric supercharger is set in the supercharging region. When the engine speed is the same as the current engine speed in the pre-rotation region, the same as when the pressure of the discharge part of the electric supercharger becomes a predetermined pressure by the control of the supercharging control means The discharge flow rate of the discharge unit is controlled when the pressure of the discharge unit becomes a predetermined pressure by the control of the supercharging control means in the supercharging region. By controlling the opening degree of the bypass valve and throttle valve so that the air flow rate becomes smaller than the air flow rate, the supercharging region can be used to control the driving speed or current of the electric supercharger in the pre-rotation region. Control means It is possible to shift from the pre-rotation region to the super-charging region with a high response so that there is no large difference with respect to the drive rotational speed or current of the electric supercharger when The drive power of the electric supercharger can be reduced, and the power consumption of the supercharger drive can be kept small.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an engine supercharging device according to an embodiment of the present invention, and this supercharging device includes an intake passage 1 for supplying intake air to the engine. An air cleaner 2 is disposed at the upstream end of the intake passage 1, and a surge tank 3 is disposed at the downstream end, and the intake air is combusted in each cylinder 4 a of the engine 4 through the surge tank 3. Each room is supplied. 1, 5 is an exhaust passage for exhausting exhaust gas from the combustion chamber of each cylinder 4a, and 6 is a cam that rotates in synchronization with the crankshaft of the engine 4 to open and close the intake valve. A shaft 7 is a variable valve timing mechanism (VVT) that changes the opening / closing timing of the intake valve.

  An electric supercharger 11 that supercharges intake air to the engine 4 is disposed in the longitudinal direction intermediate portion 1 of the intake passage 1. The electric supercharger 11 is composed of a centrifugal compressor that is rotationally driven by the electric motor. The intake air is compressed by the rotational drive by the electric motor, and the intake air is sucked into the engine 4 (combustion chamber of each cylinder 4a). It is configured to perform supercharging. The driving rotational speed of the electric supercharger 11 is controlled by the electric supercharger controller 12. The electric supercharger controller 12 controls the drive rotational speed of the electric supercharger 11 based on a control signal from the intake system controller 13. That is, the intake system controller 13 controls the drive rotation speed of the electric supercharger 11 via the electric supercharger controller 12. Note that the drive current of the electric supercharger 11 may be controlled in place of the drive rotation speed of the electric supercharger 11.

  A bypass passage 1 a is connected to the intake passage 1. Both ends of the bypass passage 1a are respectively connected to the upstream and downstream portions of the electric supercharger 11 in the intake passage 1 so as to bypass the electric supercharger 11. A bypass valve 17 driven by a bypass valve drive actuator is disposed in the bypass passage 1a.

  A throttle valve 18 driven by a throttle valve drive actuator is disposed on the downstream side of the intake passage 1 on the downstream side of the electric supercharger 11 with respect to the connection portion of the bypass passage 1a.

  The bypass valve drive actuator and the throttle valve drive actuator are driven and controlled by the intake system controller 13, respectively, and the respective openings of the bypass valve 17 and the throttle valve 18 are set to desired values. That is, the intake system controller 13 controls the opening degree of the bypass valve 17 and the throttle valve 18 and the drive rotational speed of the electric supercharger 11, and in addition to these controls, the variable valve timing mechanism 7 and the engine control system 20 are controlled.

  The torque characteristics of the engine 4 are as shown in FIG. When the electric supercharger 11 is not operated, as shown by a two-dot chain line, the maximum torque that can be generated on the low engine speed side is relatively small. When a torque higher than the maximum torque that can be produced when the electric supercharger 11 is not operated is requested, the electric supercharger 11 is operated to perform supercharging. At the time of supercharging, the electric supercharger 11 is driven to rotate at a predetermined driving power (1 kW in this embodiment) or less. Torque as shown by the solid line in FIG. 2 is generated. Therefore, the portion between the solid line and the two-dot chain line in FIG. 2 corresponds to a supercharging region set on the predetermined high load side, and when the operating state of the engine 4 is in this supercharging region, the intake system The controller 13 controls the opening degree of the bypass valve 17 and the throttle valve 18 and the rotational speed of the electric supercharger 11 so that the electric supercharger 11 is driven with a predetermined driving power. Thus, the intake system controller 13 constitutes a supercharging control means.

  The predetermined drive power is the maximum drive power that is lower than the rated drive power of the electric supercharger 11 (about 2 kW in this embodiment) and that does not cause knocking in the engine 4. That is, as shown in FIG. 3, knocking occurs when the driving power of the electric supercharger 11 exceeds 1 kW. Therefore, the ignition timing is set to MBT (Minimum Advance for the Best Torque) so that knocking does not occur. Therefore, the engine output torque is lower than MBT due to the influence. For this reason, there is no point in driving the electric supercharger 11 in a state where the driving power exceeds 1 kW, and supercharging is performed by performing supercharging below the maximum driving power (1 kW) at which knocking does not occur. While being able to carry out effectively, the power consumption of the supercharger drive at the time of supercharging can be restrained small.

  Alternatively, the predetermined drive power may be an output corresponding to the maximum power generation amount of the alternator (usually about 1 kW). If it carries out like this, while being able to cover the drive electric power of the electric supercharger 11 with the electric power generation amount of an alternator, the taking-out of the electric power from a battery can be suppressed.

  In FIG. 2, the portion on the lower torque side (the hatched portion) than the two-dot chain line corresponds to the pre-rotation region set to be adjacent to the low load side of the supercharging region, and the operating state of the engine 4 Is in the pre-rotation region, the engine 4 is not supercharged with intake air, but the electric supercharger 11 can be driven to rotate in advance to quickly shift from the pre-rotation region to the supercharging region. I am doing so. Even in this pre-rotation region, the opening degree of the bypass valve 17 and the throttle valve 18 and the driving rotational speed of the electric supercharger 11 are controlled by the intake system controller 13, whereby the intake system controller 13 In addition to the supercharging control means, a pre-rotation control means is also configured.

  Here, the supercharging control and the pre-rotation control operation in the intake system controller 13 will be described based on the flowchart of FIG.

  First, in the first step S1, various signals are read, and in the next step S2, a target surge tank pressure P (hereinafter, the pressure is a pressure ratio with respect to the atmospheric pressure), which is a target value of the pressure in the surge tank 3. In step S3, a target air flow rate Q that is a target value of the air flow rate (volume flow rate) supplied to the engine 4 through the throttle valve 18 is set.

  Specifically, as shown in FIG. 5, a required torque is obtained based on a predetermined map from the accelerator opening, the engine speed, and the gear ratio of the transmission gear, and as shown in FIG. A target surge tank pressure P and a target air flow rate Q are set based on the engine model in the engine model with a supercharger from the rotational speed. The details of this engine model are as shown in FIG. That is, the required filling efficiency CE is determined from the required torque and the engine speed based on the engine body model, and the target surge tank pressure P is determined from the required charging efficiency CE, the intake air temperature and the engine speed based on the engine intake model. The target air flow rate Q is set based on the intake manifold flow rate model from the target surge tank pressure P, the intake air temperature, and the engine speed. This intake manifold flow model has a map as shown in FIG. 8, and a straight line drawn parallel to the horizontal axis at the position of the target surge tank pressure P and an equal engine speed line corresponding to the engine speed intersect. Let the air flow rate corresponding to the position of the intersection be the target air flow rate Q.

  In the next step S4, it is determined whether the operating state of the engine 4 is in the supercharging region or the pre-rotation region based on the determination model from the actual surge tank pressure and the engine speed.

  When it is determined in step S4 that the engine is in the supercharging region, the process proceeds to step S5, where the drive rotational speed of the electric supercharger 11 is set, and in the next step S6, the opening degree of the bypass valve 17 is set, In the next step S7, the opening degree of the throttle valve 18 is set, and thereafter, the process proceeds to step S11.

  On the other hand, when it is determined in step S4 that it is in the pre-rotation region, the process proceeds to step S8, where the drive rotational speed of the electric supercharger 11 is set, and in the next step S9, the opening degree of the bypass valve 17 is set. Then, in the next step S10, the opening degree of the throttle valve 18 is set, and thereafter, the process proceeds to step S11.

  In step S11, a control signal is output to the electric supercharger 11 via the electric supercharger controller 12 so as to achieve the set drive speed, and the bypass valve drive actuator and throttle valve of the bypass valve 17 are output. A control signal is output to each of the 18 throttle valve drive actuators so that the opening degree is set as described above.

  Specifically, the settings in steps S5 to S10 are performed as follows. That is, as shown in FIG. 6, based on the target surge tank pressure P, the target air flow rate Q, and the engine rotational speed, the drive rotational speed of the electric supercharger 11 based on the supercharger intake system model of the engine model with a supercharger. The opening degree of the bypass valve 17 and the opening degree of the throttle valve 18 are set. The supercharger intake system model has a map as shown in FIG. The vertical axis of this map is the pressure in the surge tank 3 or the pressure of the discharge part of the electric supercharger 11 (both are pressure ratios relative to atmospheric pressure), and the horizontal axis is the air flow rate of the surge tank 3 or the discharge part. It is. The equal engine speed line in this map is the same as the map of the intake manifold flow model in FIG. For this reason, the coordinate position at which the pressure becomes the target surge tank pressure P and the air flow rate becomes the target air flow rate Q is located on an engine speed line. In the map of FIG. 9, the line indicating the rotational speed of 40000 rpm or the like is an equal supercharger rotational speed line when the electric supercharger 11 is rotated at the rotational speed (constant).

  When the operating state of the engine 4 is in the supercharging region, the target surge tank pressure P and the target air flow rate Q are values corresponding to the point A on the engine speed line such as the engine speed N1 (target surge). Assuming that the tank pressure P = P1 and the target air flow rate Q = Q1), the electric supercharger 11 is driven with the N1 equal engine speed line of the electric supercharger 11 equal driving power line (1 kW or less, etc.) It is performed at a point that intersects with the driving power line (here, point B intersects with the 1 kW equal driving power line). The driving rotational speed of the electric supercharger 11 at this time is set to the rotational speed (here, about 55000 rpm) of the equal supercharger rotational speed line passing through the point B. The pressure at point B is the pressure (discharge pressure) at the discharge portion of the electric supercharger 11, and is P2 in FIG. Further, the air flow rate at point B is the air flow rate of the discharge section, and is Q2 in FIG. Here, as shown in FIG. 10, a part of the air in the discharge part of the electric supercharger 11 is supplied to the engine 4 through the throttle valve 18 or the surge tank 3, while the rest passes through the bypass passage 1a. It circulates so as to flow upstream of the intake passage 1 and return to the electric supercharger 11 again. Since the target air flow rate Q is Q1, the bypass valve 17 and the air flow rate Q2 in the air flow rate Q2 become the air flow rate supplied to the engine 4 through the throttle valve 18 or the surge tank 3. Each opening degree of the throttle valve 18 is set. At this time, the opening degree of the bypass valve 17 is almost fully closed, and most of the air in the discharge part of the electric supercharger 11 is supplied to the engine 4 through the throttle valve 18 or the surge tank 3.

  On the other hand, when the operating state of the engine 4 is in the pre-rotation region, the target surge tank pressure P and the target air flow rate Q are values corresponding to the point C on the engine speed line, such as the engine speed N2. Assuming that the target surge tank pressure P = P3 and the target air flow rate Q = Q3), the drive speed of the electric supercharger 11 is the engine speed ( Here, assuming that the engine rotates at the same engine speed as N2), the pressure of the discharge part of the electric supercharger 11 becomes a predetermined pressure under the control of the intake system controller 13 (supercharging control means). The same drive speed is set. In the present embodiment, the predetermined pressure is determined by the intake supercharger 11 by the intake system controller 13 (supercharging control means) when the engine 4 is rotating at the rotation speed of N2 in the supercharging region. The pressure is the same as the pressure of the discharge part of the electric supercharger 11 when driven by driving power (1 kW). That is, the predetermined pressure is the pressure P4 at the point D where the N2 equal engine speed line in FIG. 9 intersects the 1 kW equal drive power line. The air flow rate at point D is the air flow rate at the discharge portion, and is Q4. And the drive rotation speed of the electric supercharger 11 is set to the rotation speed (here about 60000 rpm) of the equal supercharger rotation speed line which passes the said D point. This point D is a point corresponding to the point B where the electric supercharger 11 is driven when the engine speed is N1 in the supercharging region, and if the engine speed is N2 in the supercharging region, Since the electric supercharger 11 is driven at the point D (or a point that is smaller than the pressure at the point D on the equal engine speed line of N2), the engine speed is N2 from the pre-rotation region. Assuming the transition to the supercharging region remains constant, the electric rotational speed of the electric supercharger 11 in the pre-rotation region is controlled by the intake system controller 13 (supercharging control means) in the supercharging region. The value is the same as or close to the driving rotational speed of the feeder 11. Note that the predetermined pressure is not necessarily the same as the pressure of the discharge portion of the electric supercharger 11 when the electric supercharger 11 is driven with the predetermined driving power as described above. If the engine 4 is rotating at the same engine speed as the engine speed in the pre-rotation area in the supply area, what is the pressure within the pressure range that can be generated by the control result in the supercharge area? Any value may be used.

  As described above, in the pre-rotation region, the driving rotational speed of the electric supercharger 11 is set to the rotational speed of the equal supercharger rotational speed line passing through the point D. Instead of being driven, the air flow rate of the discharge part of the electric supercharger 11 is controlled so that the pressure of the discharge part becomes a predetermined pressure (P4) in the supercharging region while maintaining the rotation speed. It is driven at a position that is less than the air flow rate (Q4) of the discharge part at the time. In the present embodiment, each opening degree of the bypass valve 17 and the throttle valve 18 is controlled to perform surging in the electric supercharger 11 (a phenomenon in which abnormal vibration occurs due to separation of the air flow from the blades of the electric supercharger 11). Is driven at point E (pressure P5, air flow rate Q5 (<Q4)), which is the minimum air flow rate at which no airflow occurs. At this time, as shown in FIG. 11, the target valve air flow rate Q3 of the air flow rate Q5 becomes the air flow rate supplied to the engine 4 through the throttle valve 18 or the surge tank 3, and the bypass valve 17 and the throttle valve. Each opening degree of the valve 18 is set. At this time, the degree of opening of the bypass valve 17 is almost fully open, and most of the air in the discharge part of the electric supercharger 11 flows upstream of the intake passage 1 via the bypass passage 1a and again becomes the electric supercharger 11 again. It will circulate to return to. The electric supercharger 11 may be driven in the vicinity of the point E (the side where the air flow rate is higher than the point E) on the equal turbocharger speed line passing through the point D, or in the vicinity of the point D (D The air flow rate may be less than the point). However, driving near the side where the air flow rate is higher than point E or point E can reduce the power consumption of the supercharger drive considerably. In other words, the drive power of the equal drive power line passing through any point on the equal turbocharger speed line passing through point D becomes smaller as the intersection of the two approaches the E point. The electric power is the smallest and is considerably smaller than 1 kW. As a result, the power consumption of the supercharger drive can be kept small.

  When the operating state of the engine 4 is constant and the engine speed is shifted from the pre-rotation region to the supercharging region, the electric supercharger 11 is driven and rotated at, for example, point E in the pre-rotation region. For example, if driven at the point D, the drive rotation speed of the electric supercharger 11 remains 60000 rpm, the opening degree of the bypass valve 17 is reduced, and the opening degree of the throttle valve 18 is increased (the electric supercharger 11). The air flow supplied to the engine 4 through the throttle valve 18 or the surge tank 3 becomes the target air flow Q in the supercharging region. You can move quickly to the area. However, normally, the engine speed increases and the engine shifts from the pre-rotation area to the supercharging area. At this time, the drive speed of the electric supercharger 11 may be changed in accordance with the increase in the engine speed. The change in the driving speed can sufficiently follow the increase in the engine speed, and the response is hardly reduced. For example, when the engine speed increases from N2 to N1 and shifts from the E point to the B point, the opening degree of the bypass valve 17 and the throttle valve 18 and the driving speed of the electric supercharger 11 are controlled. Then, it may be changed along a path indicated by a two-dot chain line in FIG. Further, in the pre-rotation region, the air flow rate at the discharge portion of the electric supercharger 11 is set to the minimum air flow rate at which no surging occurs in the electric supercharger 11, so that in the range where surging does not occur, The driving power of the electric supercharger 11 can be made as small as possible, and the power consumption when driving the electric supercharger 11 can be suppressed as small as possible.

  In step S4, it may be determined that neither the supercharging region nor the pre-rotation region is present. In this case, although omitted in the flowchart, the electric supercharger 11 is in an operation stopped state. In addition, the bypass valve 17 is fully opened, and the opening degree of the throttle valve 18 is controlled in the same manner as the control of natural intake (no supercharging) that is generally performed. In this case, the intake air that has passed through the air cleaner 2 cannot pass through the portion of the intake passage 1 where the electric supercharger 11 is disposed, and therefore flows into the throttle valve 18 through the bypass passage 1a.

  INDUSTRIAL APPLICABILITY The present invention is useful for an engine supercharging device that performs supercharging of intake air to an engine by rotational driving of an electric supercharger, and in particular, supercharging that supercharges intake air to the engine as an engine operating state. This is useful in the case where a supply region and a pre-rotation region in which the electric supercharger is driven to rotate in advance without supercharging intake air to the engine are provided.

It is the schematic which shows the supercharging apparatus of the engine which concerns on embodiment of this invention. It is a figure which shows the torque characteristic of an engine. It is a figure which shows the relationship between the drive electric power of an electric supercharger when an engine speed is 1500 rpm, and an engine torque. It is a flowchart which shows the supercharging control and pre-rotation control operation | movement in an intake system controller. It is a block diagram which shows the flow of the signal for setting the drive rotation speed of an electric supercharger, the opening degree of a bypass valve, and the opening degree of a throttle valve from an accelerator opening degree, an engine speed, and the gear ratio of a transmission gear. It is a block diagram which shows the detail of the engine model with a supercharger in the block diagram of FIG. It is a block diagram which shows the detail of the engine model in the block diagram of FIG. It is a figure which shows the detail of the intake manifold flow model in the block diagram of FIG. It is a figure which shows the detail of the supercharger intake system model in the block diagram of FIG. It is a figure which shows the flow of air when the driving | running state of an engine exists in a supercharging area | region. It is a figure which shows the flow of air when the driving | running state of an engine exists in a pre-rotation area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intake passage 1a Bypass passage 4 Engine 11 Electric supercharger 13 Intake system controller (supercharging control means) (pre-rotation control means)
17 Bypass valve 18 Throttle valve

Claims (4)

An electric supercharger that is disposed in the intake passage of the engine and supercharges the intake air by electric rotation driving, a bypass passage that is provided to bypass the electric supercharger, and a bypass passage A bypass valve disposed; a throttle valve disposed downstream of the bypass passage connection portion on the downstream side of the electric supercharger of the intake passage; and an operating state of the engine on a predetermined high load side. When in the set supercharging region, the opening degree of the bypass valve and the throttle valve and the driving rotational speed or current of the electric supercharger are set so that the electric supercharger is rotationally driven at a predetermined driving power or less. When the supercharging control means to be controlled and the operating state of the engine are in a pre-rotation region set so as to be adjacent to the low load side of the supercharging region, the electric supercharger is rotationally driven in advance. Pre-rotation for A supercharging device for an engine provided with a control means,
When the operating state of the engine is in the pre-rotation region, the pre-rotation control means is configured to calculate the drive rotational speed or current of the electric supercharger in the super-charging region. When the engine speed is the same as the engine speed, the same drive speed or current as when the pressure of the discharge part of the electric supercharger becomes a predetermined pressure under the control of the supercharging control means. And the air flow rate of the discharge unit is higher than the air flow rate of the discharge unit when the pressure of the discharge unit becomes a predetermined pressure by the control of the supercharging control means in the supercharging region. A supercharging device for an engine, characterized in that each opening degree of the bypass valve and the throttle valve is controlled so as to be reduced. The engine supercharging device according to claim 1,
The pre-rotation control means is configured so that each of the bypass valve and the throttle valve has an air flow rate at a discharge portion of the electric supercharger that is at or near a minimum air flow rate at which surging does not occur in the electric supercharger. An engine supercharging device configured to control an opening degree. The engine supercharging device according to claim 1 or 2,
The engine supercharging device, wherein the predetermined driving power is a maximum driving power that is lower than a rated driving power of the electric supercharger and does not cause knocking in the engine. The engine supercharging device according to claim 1 or 2,
An alternator driven by the engine,
The engine supercharging device, wherein the predetermined drive power is an output corresponding to a maximum power generation amount of the alternator.

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