JP2007071137A - Supercharging device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the deterioration in fuel economy, and to restrain the deterioration in a battery while securing rising responsiveness of supercharging pressure in a supercharging device of an engine having a motor-driven supercharger. <P>SOLUTION: This supercharging device of the engine has a supercharging passage provided with the motor-driven supercharger, a bypass passage connected to the upstream-downstream side of the motor-driven supercharger in the supercharging passage and provided with an intake control valve, and a confluent passage extending to the downstream side from a confluent part of the supercharging passage and the bypass passage and provided with a throttle valve; and is constituted so as to supply electric power to the motor-driven supercharger when an operation state of the engine exists in a predetermined supercharging area and stop supply of the electric power to the supercharger when the operation state exists in a non-supercharging area set on the lower load side than a supercharging area; and starts the supply of the electric power to the motor-driven supercharger when a predetermined period passes after closing the intake control valve when the operation state of the engine transfers to the supercharging area from the non-supercharging area. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine supercharger having an electric supercharger, and belongs to the technical field of an engine intake system.

  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.

  And as an intake system provided with this electric supercharger, for example, in Patent Document 1, a supercharging passage in which the electric supercharger is disposed, and an electric supercharger in the supercharging passage above and downstream of the supercharger. Disclosed is an intake system provided with a bypass passage that is connected and provided with an intake control valve, and a merging passage that extends downstream from a merging portion of the supercharging passage and the bypass passage and is provided with a throttle valve. Has been. In this intake system, when the engine operating region is in a predetermined supercharging region on the high load side, the electric supercharger is operated with the intake control valve closed. The intake air amount of the engine is controlled by controlling the opening of the throttle valve as usual.

On the other hand, this type of electric supercharger has a compressor and a motor that drives the compressor, and the number of rotations of the compressor increases or decreases according to the power supplied to the motor, and the resulting supercharging pressure is determined. become. Here, Patent Document 2 discloses an invention relating to control of power supply to an electric supercharger. That is, in the invention described in Patent Document 2, normally, the power supplied to the electric supercharger is large when the pressure difference is large based on the difference between the target supercharging pressure and the actual supercharging pressure at the time of supercharging. The supercharging pressure feedback control is performed so as to increase the supply power, but at the start of supercharging, that is, only when the engine operating state enters the supercharging region, the supercharger is It is controlled to supply the maximum power. As a result, the rotational speed of the electric supercharger is quickly increased, and the responsiveness of the rise of the supercharging pressure when entering the supercharging region is ensured. In the following description, the electric power supplied to the supercharger when the engine operating region enters the supercharging region is referred to as “rush power”.
JP 2004-346910 A JP 2004-169629 A

  By the way, the electric supercharger is usually driven based on the generated power of the alternator driven by the engine. However, in order to ensure responsiveness as when the electric supercharger is started. When a large inrush power is required, the required power cannot be covered by the power supplied from the alternator, and the power is taken out from the battery. At this time, the power taken out from the battery is not small, which may promote the deterioration of the battery, and the power generation time of the alternator increases for charging the battery, resulting in a problem of deterioration in fuel consumption. Moreover, in an operating state where acceleration and deceleration are repeated, the transition from the non-supercharged region to the supercharged region of the operating state is repeated, and power is taken out from the battery at each transition, and the above-described deterioration of the battery In addition, the problem of deterioration in fuel consumption becomes prominent, and the user is forced to replace the battery frequently.

  On the other hand, in a state where the operating state is in the non-supercharging region, predetermined electric power is supplied to the electric supercharger, the rotational speed is increased in advance, and the inrush power when shifting to the supercharging region is suppressed. Although it is conceivable, the operation time of the alternator becomes longer due to the necessity of the predetermined power supply, and the deterioration of fuel consumption becomes a problem.

  Accordingly, an object of the present invention is to prevent deterioration of fuel consumption and suppress deterioration of a battery while ensuring responsiveness of rising of a supercharging pressure in an engine supercharging device having an electric supercharger. .

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

  First, the invention according to claim 1 is provided with a supercharging passage provided with an electric supercharger, and an intake control valve connected to the upstream side of the electric supercharger in the supercharging passage. A bypass passage and a joining passage that extends downstream from a joining portion of the supercharging passage and the bypass passage and is provided with a throttle valve, and the engine operating state is in a predetermined supercharging region. The power supply to the electric supercharger is performed, and the power supply to the supercharger is stopped when the electric supercharger is in a non-supercharge region set at a lower load side than the supercharge region. An engine supercharger that closes the intake control valve when the operating state of the engine shifts from the non-supercharged region to the supercharged region, and then when the predetermined period has elapsed, the electric supercharger The power supply to is started.

  In the state where the power supply to the supercharger is stopped in the non-supercharged region, the motor is rotated at a very low speed with a small amount of electric power for the purpose of recognizing the rotational phase of the supercharger motor. Including the state.

  The invention according to claim 2 is the engine supercharging device according to claim 1, further comprising a supercharger rotation speed detection means for detecting the actual rotation speed of the electric supercharger, and the operation of the engine. When the state transitions from the non-supercharged region to the supercharged region and starts supplying power to the electric supercharger, the actual rotational speed immediately before the start of power supply of the electric supercharger detected by the detecting means The larger the difference from the target rotational speed at the time of supercharging, the larger the power supplied to the supercharger.

  Further, the invention according to claim 3 is the engine supercharging device according to claim 1, wherein when the operating state of the engine shifts from the supercharging region to the non-supercharging region, The power supply is stopped, and then, when a predetermined period has elapsed, the closing operation of the throttle valve is started.

  According to a fourth aspect of the present invention, in the engine supercharging device according to the third aspect, when the operating state of the engine shifts from the supercharging region to the non-supercharging region, An opening operation of the intake control valve is started when a predetermined period elapses after the power supply is stopped.

  First, according to the first aspect of the present invention, when the engine operating state shifts from the non-supercharged region to the supercharged region, the intake control valve is closed, and then when the predetermined period has elapsed, Power supply to the supercharger is started. Here, in a state where the intake control valve is closed and power is not supplied to the supercharger, the intake negative pressure generated in the combustion chamber reaches the supercharge passage through the merge passage, and upstream of the supercharge passage. An air flow is generated in the supercharging passage due to a pressure difference with the side. Then, the supercharger is rotated by the air flow in the supercharging passage.

  In addition, when the intake control valve is closed, the turbocharger is powered up with a predetermined period of time to increase the rotation of the turbocharger. Compared to the above, since the rotation can be increased with a small energy, the inrush power is suppressed. As a result, an increase in the ratio that can be covered by the generated power of the alternator prevents the power from being taken out of the battery, thereby preventing the battery from deteriorating. At this time, although the inrush power is suppressed, the rotation can be quickly increased, so that the responsiveness at the rise of the supercharging pressure is not deteriorated, and the fuel consumption is deteriorated by suppressing the inrush power. Is prevented.

  By the way, it is possible to reduce the inrush power by rotating the supercharger in this way, but assuming that the inrush power is constant, the operating state of the engine shifts from the non-supercharge region to the supercharge region, When power supply to the turbocharger is started, if there is a large difference between the actual rotation speed just before the start of power supply and the target rotation speed at the time of supercharging, there is a possibility that a response delay will occur due to insufficient power, and rotation When the number difference is small, an effect of improving fuel efficiency may not be obtained efficiently due to excessive supply of electric power.

  On the other hand, according to the invention described in claim 2, the power supplied to the supercharger increases as the difference between the actual rotational speed immediately before the start of power supply of the supercharger and the target rotational speed at the time of supercharging increases. Therefore, when the rotational speed difference is large, the supplied power is increased to ensure the responsiveness of the boost pressure rise, and when the rotational speed difference is small, the supplied power is reduced to prevent excessive supply of power. As a result, fuel efficiency is improved efficiently.

  On the other hand, when the engine operating state shifts from the supercharging region to the non-supercharging region during deceleration, etc., the throttle valve opening is simultaneously reduced and the intake control valve is opened to perform normal non-supercharging. However, when the throttle valve is closed, the influence of the negative intake pressure in the combustion chamber on the upstream side of the throttle valve is reduced, so the air flow upstream of the throttle valve becomes weaker. The air flow in the supercharging passage is also weakened. As a result, the rotation effect of the supercharger described above is lost, and the rotation of the supercharger decreases rapidly. For this reason, when the transition is made again from the non-supercharged region to the supercharged region, the rotation is increased from a small rotation state or a stopped state. As a result, the fuel efficiency is not improved efficiently. In particular, when the operating state is in the vicinity of the boundary between the supercharging region and the non-supercharging region, the rushing into the supercharging region may be repeatedly performed, and there is room for improvement.

  On the other hand, according to the invention described in claim 3, when the operating state of the engine shifts from the supercharging region to the non-supercharging region, the power supply to the supercharger is stopped, and thereafter, for a predetermined period. When the time has elapsed, the closing operation of the throttle valve is started. As a result, the loss of the air flow in the supercharging passage immediately after the transition to the non-supercharging region is avoided, so that the rotation effect of the supercharger is not lost. And when it transfers to a supercharging area | region again from a non-supercharging area | region, since required energy becomes small, inrush electric power is suppressed and a fuel consumption is improved efficiently.

  According to the fourth aspect of the present invention, the opening operation of the intake control valve is started after a predetermined period of time has elapsed since the power supply to the supercharger. As a result, air flows exclusively through the supercharging passage due to the intake negative pressure, and the rotation effect of the supercharger is maintained. Therefore, when the transition is made again from the non-supercharging region to the supercharging region, the inrush electric power is more effectively suppressed and the fuel efficiency is efficiently improved.

  Embodiments of the present invention will be described below.

  FIG. 1 shows an intake system 1 for an engine according to the present embodiment. The intake system 1 has an intake passage 2 through which fresh air is introduced. The intake passage 2 is connected to an air cleaner 10 on the upstream side, and a supercharging passage 20 in which an electric supercharger 11 is disposed; A bypass passage 21 connected to the upstream side and the downstream side of the supercharger 11 in the supercharging passage 20 and provided with the intake control valve 12, and extends to the downstream side where the supercharging passage 20 and the bypass passage 21 merge. A merging passage 22 in which the throttle valve 13 is disposed, a surge tank 23 formed on the downstream side of the merging passage 22, and a plurality of independent intake passages branched from the surge tank 23 to the respective cylinders # 1 to # 4. 24 ... 24.

  The electric supercharger 11 is configured such that the compressor 11b rotates by supplying electric power to the motor 11a, and air sucked from the upstream side of the supercharger 11 in the supercharging passage 20 is pumped downstream. It has become. In addition, the power consumption at the time of the rated output of this supercharger 11 is 2 kW.

  In addition, an electric supercharger driver 30 that controls the supply current to the motor 11 a of the electric supercharger 11, and a battery 31 and an alternator 32 that supply electric power to the motor 11 a via the driver 30 are provided. The battery 31 is a 14V power source, and is connected to the driver 30 so as to be able to supply power as indicated by an arrow A, and can store the electric power generated by the alternator 32. The alternator 32 is configured to generate a voltage of 14 V by driving the engine. The alternator 32 directly supplies power to the driver 30 as indicated by an arrow B, while supplying power to the battery 31 as indicated by an arrow C. To charge.

  An engine control unit 100 that controls the entire engine and an intake system controller 101 that controls each device of the intake system 1 based on a control signal output from the engine control unit 100 are provided.

  The engine control unit 100 detects the engine load as a signal from an accelerator opening sensor 40 that detects the depression amount of the accelerator pedal 40a, a signal from the engine speed sensor 41 that detects an engine speed, and the battery 31. A signal from a voltage sensor 42 for detecting the charging state of the motor 11 and a motor rotational speed sensor 43 for detecting the rotational speed of the motor 11a of the electric supercharger 11 are input.

  Based on these input signals, the engine control unit 100 outputs various control signals to the throttle actuator 44 that drives the throttle valve 13 to open and close, the intake system controller 101, and the like.

  The intake system controller 101 outputs a control signal to the intake control valve actuator 45 that opens and closes the intake control valve 12, the electric supercharger driver 30, and the like.

  By the way, as shown in FIG. 2, the engine control unit 100 stores a control map in which each operation region is set according to the accelerator opening and the engine speed. In this control map, a non-supercharging region is set on the low load side and the high rotation side, and a supercharging region is set on the high load low rotation side.

  In the non-supercharging region, the engine control unit 100 fully opens the intake control valve 12 to the intake control valve actuator 45 via the signal for controlling the opening of the throttle valve 13 to the throttle actuator 44 and the intake system controller 101. The signal to be output is output. Further, the engine control unit 100 outputs a signal for supplying a minute current to the motor 11 a to the electric supercharger driver 30 via the intake system controller 101. The throttle valve 13 is of an electronic control type, and the throttle opening does not necessarily correspond to the depression amount of the accelerator pedal 40a.

In the supercharging region, the engine control unit 100 sends the intake control valve 12 to the intake control valve actuator 45 via the intake system controller 101 and the signal for controlling the opening of the throttle valve 13 to the throttle actuator 44. Outputs a signal to fully close. In this supercharging region, the engine control unit 100 supplies the supercharger 11 with a supply current represented by the following expression 1 to the electric supercharger driver 30 via the intake system controller 101. Output a signal.
Supply current = Base current + (Target speed-Actual speed) x Gain (Formula 1)

  Here, the base current is a current value required to realize the power supply of 1 kW. Further, the target rotational speed of the supercharger 11 at the time of supercharging is determined according to the accelerator opening and the engine rotational speed. Then, a value obtained by subtracting the actual rotational speed detected by the motor rotational speed sensor 43 from the target rotational speed of the supercharger 11 and a predetermined gain is added to the base current, and this is supplied as a total supply. It is current.

  By the way, the above-described control is basically performed in the supercharging region and the non-supercharging region. However, when the transition is made from the non-supercharging region to the supercharging region, and the transition is made from the supercharging region to the non-supercharging region. When the following control is performed.

  That is, when shifting from the non-supercharged region to the supercharged region, the engine control unit 100 first outputs a signal for closing the intake control valve 12 via the intake system controller 101, to the electric supercharger driver 30. When the rotation speed of the supercharger 11 is less than 15000 rpm, a minute power supply for idle rotation is performed, and when the rotation speed is 15000 rpm or more, a signal for supplying the power supply for supercharging according to the equation 1 is output. It is like that.

  When the engine control unit 100 shifts from the supercharging region to the non-supercharging region, the engine control unit 100 first supplies a small amount of power to the supercharger 11 to the electric supercharger driver 30 via the intake system controller 101. When the rotational speed of the supercharger 11 is larger than 5000 rpm, the intake control valve 12 is closed and the throttle valve 13 is output a signal for maintaining the throttle opening in the supercharging region, and the rotational speed is 5000 rpm or less. In this state, the intake control valve 12 is opened and the throttle valve 13 is decreased to the throttle opening corresponding to the target torque after shifting to the non-supercharging region, and a signal for returning to normal throttle control is output. .

  Next, the operation of the intake system 1 will be described.

  First, when the engine operating state is in the non-supercharging region, the engine control unit 100 outputs a signal for controlling the throttle valve 13 and a signal for fully opening the intake control valve 12 via the intake system controller 101. Therefore, the air introduced into the intake passage 2 reaches the merging passage 22 through the bypass passage 21 and is sucked into the engine according to the opening degree of the throttle valve 13. The opening of the throttle valve 13 controls the intake air amount so that the target torque is obtained with respect to the target torque calculated based on the parameters of the accelerator opening and the engine speed.

  Further, in this region, by supplying a small current to the electric supercharger 11, the supercharger 11 maintains an idle rotation (5000 rpm) without a rotation effect described later. By performing idle rotation in this way, the engine control unit 100 can always recognize the rotational phase of the motor 11a, so that the control response of the supercharger 11 when the operating state shifts to the supercharging region. This improves the responsiveness of the boost pressure rise.

  As a result, as shown in FIG. 3, in the non-supercharging region, engine characteristics are obtained in which high torque can be obtained on the high rotation side only by natural intake.

  When the engine operating state is in the supercharging region, the engine control unit 100 outputs a signal for controlling the throttle valve 13 and a signal for fully closing the intake control valve 12 via the intake system controller 101. Therefore, the air introduced into the intake passage 2 cannot pass through the bypass passage 21 and can pass only through the supercharging passage 20. Then, the electric supercharger 11 operates with electric power equal to or higher than the base current supply power (1 kW), and the air introduced into the supercharging passage 20 is pumped to the downstream side of the supercharger 11. Further, the pumped air is introduced into the merging passage 22 and is sucked into the engine according to the opening degree of the throttle valve 13.

  As a result, as shown in FIG. 3, in the supercharging region, a torque greater than that obtained by only natural intake is obtained mainly on the low rotation side.

  Further, when the supercharger 11 is shifted from the non-supercharge region to the supercharge region, the intake control valve 12 is closed and power is not supplied to the supercharger 11 when the rotational speed of the supercharger 11 is less than 15000 rpm. The intake negative pressure in the combustion chamber reaches the supercharging passage 20 via the merging passage 22, and the supercharger 11 rotates due to the air flow in the supercharging passage 20 generated by the negative pressure. Further, when the rotation speed increases due to this rotation and becomes 15000 rpm or more, the control is switched to the control of the supply current expressed by the above formula 1, so the control of the supercharging region is performed.

  Further, when the supercharger 11 shifts from the supercharge region to the non-supercharge region, a signal for closing the intake control valve 12 and opening the throttle valve 13 is output when the rotational speed of the supercharger 11 is greater than 5000 rpm. As shown in FIG. 4, after the air flow is generated in the supercharging passage 20 due to the negative intake pressure, and the supply current is switched to a minute one for idle rotation, the rotation of the supercharger 11 gradually decreases. It will be. In the state where the rotational speed is 5000 rpm or less, the intake control valve 12 is opened and the throttle valve 13 is decreased to the throttle opening corresponding to the target torque after shifting to the non-supercharging region. Is controlled.

  Next, control of the intake system 1 will be described based on the flowchart shown in FIG.

  First, in step S1, various signals are read. At this time, the accelerator opening detected by the accelerator opening sensor 40, the engine rotation speed detected by the engine rotation speed sensor 41, the rotation speed signal of the motor 11a detected by the motor rotation speed sensor 43, and the like are input. Next, in step S2, a target torque is determined based on the accelerator opening and engine speed parameters. This target torque is obtained by calculation or by a map.

  Then, in step S3, it is determined whether or not the engine operating state is in the supercharging region based on the control map shown in FIG.

  Here, as shown in the time chart of FIG. 6, when the accelerator pedal 40a is depressed at time t0 and an acceleration request is made, the throttle opening is increased and indicated by an arrow X in FIG. Thus, it is determined that the operating state has shifted to the supercharging region. At this time, as a result of the determination in step S3, the process proceeds to step S4. In step S4, the intake control valve 12 is closed. Next, in step S5, whether the rotational speed of the supercharger 11 is equal to or greater than a predetermined value α (= 15000 rpm). Judgment is made. When the rotational speed of the supercharger 11 is less than the predetermined value α in step S5, the process proceeds to step S6. The supercharger 11 is supplied with a small amount of power for idle rotation, and the process proceeds to step S7. Torque control is performed by controlling the throttle valve 13 in order to realize the target torque obtained in (1).

  On the other hand, as indicated by the symbol a in FIG. 6, the rotational speed of the supercharger 11 increases due to rotation from time t0 and becomes equal to or higher than the predetermined value α at time t1, and the rotational speed of the supercharger 11 is increased in step S5. When it is determined that α is greater than or equal to α, the routine proceeds to step S8, where a predetermined current for supercharging is supplied to the supercharger 11, that is, the current control to the supercharger 11 is idled as indicated by the symbol a in FIG. The control is switched from the rotation control to the supercharging control, and the process proceeds to step S7. At this time, the current supplied to the supercharger 11 is obtained by multiplying the difference between the target rotational speed of the supercharger 11 and the actual rotational speed by a predetermined gain as shown in the above-described equation 1, and the base current. It is obtained by adding to.

  Then, as a result of such control when shifting to the supercharging region, as shown in FIG. 7, the supercharger 11 is increased to a rotational speed of 15000 rpm due to the above-described autorotation effect. Then, when power supply to the supercharger 11 is started, as shown in FIG. 8, the transition from the state with rotation with a high actual rotational speed is higher than the transition from the state without rotation. Inrush current is reduced. Then, the rotation speed of the supercharger 11 increases due to the power supply, and the supply current decreases as the rotation speed increases. When the rotation speed is constantly rotating at 60000 rpm, the supply current is the base current. I 'and the power consumption is maintained at 1 kW.

  On the other hand, as shown in the time chart of FIG. 9, when the amount of depression of the accelerator pedal 40a decreases at time t2 and a deceleration request is made, the driving state is changed to the non-supercharging region as shown by the arrow Y in FIG. It is determined that the transition has occurred. At this time, as a result of the determination in step S3, the process proceeds to step S9. In step S9, the supply current to the supercharger 11 is controlled for idle rotation as indicated by the symbol C in FIG. 9, and the rotational speed of the supercharger 11 is equal to or less than a predetermined value β (= 5000 rpm) in step S10. It is determined whether or not.

  As indicated by reference numeral d in FIG. 9, as a result of switching the supply current to the supercharger 11 to idle rotation at time t2, the rotational speed of the supercharger 11 gradually decreases from time t2 to t3. Here, since the rotational speed of the supercharger 11 is greater than the predetermined value β at times t2 to t3, the process proceeds to step S11 in the determination of step S10, the intake control valve 12 is closed, and the throttle valve 13 is determined at step S12. As the control, the throttle opening is controlled to be maintained in the previous state.

  At this time, in steps S11 and S12, as shown in FIG. 4, the intake control valve 12 is closed and the throttle valve 13 is maintained in a large opening state. An air flow is generated in the supercharging passage 20 due to the negative pressure, and the supercharger 11 is rotated. As a result, as described above, the decrease in the rotational speed of the supercharger 11 becomes moderate at times t2 to t3.

  Further, when the rotational speed of the supercharger 11 decreases to the predetermined value β at time t3 in FIG. 9, the process proceeds to step 13 in the determination of step S10, and the intake control valve 12 is opened as indicated by reference symbol o. As indicated by the reference symbol, in step S14, the throttle valve 13 is controlled so that the throttle opening corresponding to the target torque after the shift to the non-supercharging region is reduced to return to the normal control.

  By the way, the time chart of FIG. 10 shows control when the operating state shifts to the non-supercharging region and then shifts to the supercharging region again. First, when the amount of depression of the accelerator pedal 40a decreases at time t2 and a deceleration request is made, the operating state shifts to the non-supercharging region, and power is supplied to the supercharger 11 at the same time as indicated by the reference sign. It can be switched to a small one for idle rotation.

  When the rotation speed of the supercharger 11 decreases as indicated by the reference symbol Q, but the acceleration pedal 40a is depressed at the time t4 before it decreases to the predetermined value β, there is a request for acceleration. The operating state shifts to the supercharging region, and at the same time, the supply current to the supercharger 11 is switched to the supercharging control, as indicated by reference symbols. As a result, the rotational speed of the supercharger 11 rises to the target speed as indicated by the reference symbol “C”. At this time, an increase in rotation from the rotation state immediately before the start of current supply to the target rotation is L1.

  As described above, after the transition to the non-supercharging region, when shifting to the supercharging region before the rotational speed of the supercharger 11 decreases to β, the opening of the throttle valve 13 is maintained in a large state. The intake control valve 12 is maintained in an open state.

  On the other hand, FIG. 10 shows a case where the control is performed so as to close the throttle valve 13 and open the intake control valve 12 as indicated by the reference sign when the shift to the non-supercharging region is performed. . According to this, since the intake negative pressure is blocked by the throttle valve 13 by closing the throttle valve 13, the flow of air in the merging passage 22 decreases. Since the air introduced into the intake passage 2 exclusively passes through the bypass passage 21, the flow of air in the supercharging passage 20 is reduced, and the rotation effect of the supercharger 11 is lost. In addition, the rotation of the supercharger 11 rapidly decreases. When the acceleration is requested at time t4, the supercharger 11 decreases the rotational speed to idle rotation, and increases from here to the target rotation, as shown by reference numeral, but increases to the target rotation. The cost is L2 larger than L1, and as a result, the inrush current must be increased in order to ensure the rise of the supercharging pressure.

  Next, a second embodiment of the present invention will be described. This second embodiment has the same apparatus configuration as the first embodiment, but differs in the control method.

That is, when a transition from the non-supercharging region supercharging region, the engine control unit 100, and outputs a first signal for closing the intake control valve 12 via an intake system controller 101, so as to set the timer T ₁ ing. Before the timer T ₁ elapses, a small amount of electric power is supplied to the electric supercharger driver 30, and after the timer T ₁ elapses, a signal for realizing the supply current according to the equation 1 is output.

When the engine control unit 100 shifts from the supercharging region to the non-supercharging region, the engine control unit 100 first supplies a small amount of power to the supercharger 11 to the electric supercharger driver 30 via the intake system controller 101. It outputs a signal to set the timer T _2. Then, the timer T ₂ has elapsed before outputs a signal for opening the throttle valve 13 closes the intake control valve 12, the timer T ₂ after after migrating the throttle valve 13 opens the intake control valve 12 in the non-supercharging region A throttle opening corresponding to the target torque is reduced to a signal for returning to normal throttle control.

Then, the when a transition from non-supercharging region supercharging region, the timer T ₁ elapses before is not power the turbocharger 11 is closed intake control valve 12, the intake negative pressure in the combustion chamber The supercharger 11 rotates by the flow of air in the supercharging passage 20 generated by the negative pressure and reaching the supercharging passage 20 through the junction passage 22. Also, increases the rotational speed by the rotation, a timer T ₁ after the control of the current supply for supercharging, i.e. switched to the control of the supply current of the above formula 1, the control of the supercharging region Will be started.

Further, when a transition from said supercharging region in the non-supercharging region, the timer T ₂ has elapsed before closing the intake control valve 12, the signal for opening the throttle valve 13 is outputted, as shown in FIG. 4 In addition, an air flow is generated in the supercharging passage 20 due to the intake negative pressure, and the rotation of the supercharger 11 gradually decreases. The timer T ₂ after since the signal for switching the throttle valve 13 to the normal control by opening the intake control valve 12 is output, the same state as the non-supercharging zone.

  The control of the intake system 1 in this embodiment will be described based on the flowchart of FIG.

  First, in step S21, various signals are read. At this time, the accelerator position detected by the accelerator position sensor 40, the engine speed detected by the engine speed sensor 41, and the rotation speed signal of the motor 11a detected by the motor speed sensor 43 are input. Next, in step S22, a target torque is determined based on the accelerator opening and engine speed parameters. This target torque is obtained by calculation or by a map.

  In step S23, it is determined whether or not the engine operating state is in the supercharging region based on the map shown in FIG.

Here, as shown in the time chart of FIG. 12, when the amount of depression of the accelerator pedal 40a is increased at time t0 to request acceleration, the throttle opening is increased at the same time, as indicated by the arrow X in FIG. It is determined that the operating state has shifted to the supercharging region. At this time, as a result of the determination in step S23, the process proceeds to step S24 to close the intake control valve 12, and in step S25, it is determined whether or not it was in the previous non-supercharging region. When it is determined that the last is a non-supercharging region, that is, when it is immediately after the transition to the supercharging region, the process proceeds to step S26, sets the timer T _1. Next, in step S27, a small amount of electric power is supplied to the supercharger 11 to control the idle rotation, and in step S28, the opening degree of the throttle valve 13 is controlled to achieve the target torque obtained in step S22.

Also, if not the last non-supercharging region in step S25, the process proceeds to step _S29, a determination is whether _T 1 = 0, when the _{T 1} ≠ 0 after having decremented _{T 1} in step S30, step Proceed to S27.

Further, when it is determined in step S29 that T ₁ = 0, that is, at time t0 + T ₁ shown in FIG. 12, a predetermined current for supercharging is supplied to the electric supercharger 11 in step S31 as shown by reference sign S0. The process proceeds to step S28. At this time, the current supplied to the supercharger 11 is obtained by multiplying the difference between the target rotational speed of the supercharger 11 and the actual rotational speed by a predetermined gain as shown in the above-described equation 1, and the base current. It is obtained by adding to. Then, the process proceeds to step S28.

On the other hand, when the amount of depression of the accelerator pedal 40a decreases at time t2 and a deceleration request is made, it is determined that the driving state has shifted to the non-supercharging region as indicated by the arrow Y in FIG. At this time, as a result of the determination in step S23, the supercharger 11 is controlled to the idle rotation state in step S32, and it is determined whether or not it was the previous supercharging region in step S33. When it is determined that the last is a supercharge region, that is, when it is immediately after the transition to the non-supercharging region, the process proceeds to step S34, it sets the timer T _2. Next, in step S35, the intake control valve 12 is closed, and in step S36, the throttle valve 13 is controlled to maintain the previous throttle opening.

  At this time, in steps S33 and S34, the intake control valve 12 is closed and the throttle valve 13 is maintained in a state where the opening degree is large, so that the intake negative pressure reaches the supercharging passage 20 via the merging passage 22. The negative pressure causes an air flow in the supercharging passage 20 to rotate the supercharger 11. As a result, as described above, the decrease in the rotational speed of the supercharger 11 becomes moderate at times t2 to t3.

On the other hand, when it is determined in step S33 that it is not the previous supercharging region, the process proceeds to step S37, where it is determined whether T ₂ = 0, and when T ₂ ≠ 0, T ₂ is decremented in step S38. Above, it progresses to step S35.

Furthermore, when it is determined in step S37 that T ₂ = 0, that is, at time t2 + T ₂ shown in FIG. 13, the intake control valve 12 is opened as indicated by reference numeral in step S39, and indicated by reference numeral H in step S40. As described above, the control of the throttle valve 13 is reduced to the throttle opening corresponding to the target torque at the time of transition, and returned to the normal control.

Incidentally, the timer T ₂ are, are set to a time sufficient rotation of the supercharger 11 is to idle rotation state attenuation. Further, the time from when the rotation of the supercharger 11 is attenuated to idle rotation depends on the number of revolutions of the supercharger 11 when the supercharger region shifts to the non-supercharge region, and is shown in FIG. based on the map, it may be to increase the value speed higher timer T ₂ of the turbocharger 11.

  As described above, according to the first and second embodiments, when the engine operating state shifts from the non-supercharging region to the supercharging region, the intake control valve 12 is first closed, and the intake control is performed. After the valve 12 is closed, after a predetermined time has elapsed, or after the rotational speed of the supercharger 11 has increased to a predetermined rotational speed, power supply to the electric supercharger 11 is started. Here, in a state where the intake control valve 12 is closed and power is not supplied to the supercharger 11, the intake negative pressure generated in the combustion chamber reaches the supercharging passage 20 via the merging passage 22. Due to the pressure difference from the upstream side of the supply passage 20, an air flow occurs in the supercharging passage 20. Then, the supercharger 11 rotates by the air flow in the supercharging passage 20.

  In addition, after the intake control valve 12 is closed, the turbocharger 11 is supplied with electric power after a predetermined period of time to increase the rotation of the supercharger 11. However, the rotation of the turbocharger is stopped. Since the rotation can be increased with a small energy compared to the case of increasing, the inrush power is suppressed. As a result, the proportion of power generated by the alternator 32 can be increased, thereby preventing the power from being taken out from the battery 31 and preventing the battery 31 from deteriorating. At this time, although the inrush power is suppressed, the rotation can be quickly increased, so that the responsiveness at the rise of the supercharging pressure is not deteriorated, and the fuel consumption is deteriorated by suppressing the inrush power. Is prevented.

  By the way, the inrush power can be reduced by rotating the supercharger 11 in this way, but if the inrush power is made constant, the engine operating state shifts from the non-supercharge region to the supercharge region. When the power supply to the supercharger 11 is started, if the difference between the actual rotational speed immediately before the start of power supply and the target rotational speed at the time of supercharging is large, there is a possibility that a response delay may occur due to insufficient power. When the difference in rotational speed is small, there is a case where the effect of improving fuel efficiency cannot be obtained efficiently due to excessive supply of electric power.

  On the other hand, as shown in the formula 1, the power supplied to the supercharger 11 increases as the difference between the actual rotational speed immediately before the start of power supply to the supercharger 11 and the target rotational speed at the time of supercharging increases. Therefore, when the rotational speed difference is large, the supplied power is increased to ensure the responsiveness of the boost pressure rise, and when the rotational speed difference is small, the supplied power is reduced to prevent excessive supply of power. As a result, fuel efficiency is improved efficiently.

  On the other hand, when the engine operating state shifts from the supercharging region to the non-supercharging region during deceleration or the like, at the same time, the opening degree of the throttle valve 13 is reduced and the intake control valve 12 is opened to perform normal non-charging. Although the control is switched to the control in the supercharging region, when the throttle valve 13 is closed, the influence of the intake negative pressure in the combustion chamber on the upstream side of the throttle valve 13 is reduced, and the air on the upstream side of the throttle valve 13 is reduced. The flow is weakened, and the air flow in the supercharging passage 20 is also weakened. As a result, the rotation effect of the supercharger 11 is lost, and the rotation of the supercharger 11 is rapidly reduced. For this reason, when the transition is made again from the non-supercharged region to the supercharged region, the rotation is increased from a small rotation state or a stopped state. As a result, the fuel efficiency is not improved efficiently. In particular, when the operating state is in the vicinity of the boundary between the supercharging region and the non-supercharging region, the rushing into the supercharging region may be repeatedly performed, and there is room for improvement.

  On the other hand, when the engine operating state shifts from the supercharging region to the non-supercharging region, the power supply to the supercharger 11 is stopped, and the throttle valve 13 is not immediately closed and a predetermined time has elapsed. After or after the rotation is naturally attenuated and the rotational speed of the supercharger 11 is reduced to a predetermined rotational speed, the throttle valve 13 is closed, so that the merging passage 22 and the supercharging passage 20 as described above. The pressure of the turbocharger 11 is prevented from increasing, and the rotation effect of the supercharger 11 is not lost, and the energy required when the transition from the non-supercharging region to the supercharging region is reduced again. Is suppressed, and fuel efficiency is efficiently improved.

  Further, by delaying the closing operation of the throttle valve 13 and also delaying the opening operation of the intake control valve 12 in this manner, a state in which negative pressure is generated in the merging passage 22 and the supercharging passage 20 is maintained. When the rotation effect of the charger 11 is maintained and the transition from the non-supercharging region to the supercharging region is made again, the inrush electric power is more effectively suppressed and the fuel efficiency is efficiently improved.

  FIG. 15 shows the case where the intake control valve 12 is simultaneously controlled to be opened and only the closing operation of the throttle valve 13 is delayed when power is supplied to the supercharger 11. As described above, an effect of preventing a loss of the rotation effect due to a part of the air passing through the supercharging passage 20 can be obtained.

  The present invention relates to an engine supercharger having an electric supercharger and is widely suitable for the automobile industry.

1 is an overall view of an intake system according to an embodiment of the present invention. It is a control map which shows the operation area | region of an engine. It is explanatory drawing of the output characteristic of an engine. It is explanatory drawing of the flow of the air which rotates a supercharger. It is a flowchart which concerns on control of an intake system. It is a time chart when transfering to a supercharging area | region. It is explanatory drawing of the rotation speed of the supercharger at the time of an electric power supply start. It is explanatory drawing of the inrush current of the supercharger at the time of an electric power supply start. It is a time chart when shifting to a non-supercharging region. It is a time chart when changing to a supercharging area | region again after a non-supercharging area | region transfer. It is a flowchart which concerns on control of the intake system of the 2nd Embodiment of this invention. It is a time chart when transfering to a supercharging area | region. It is a time chart when shifting to a non-supercharging region. Is a map of the values of T ₂ corresponding to the rotational speed of the supercharger. It is explanatory drawing of the flow of the air which rotates a supercharger.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intake system 11 Electric supercharger 12 Intake control valve 13 Throttle valve 20 Supercharging passage 21 Bypass passage 22 Merge passage 43 Motor rotation speed sensor

Claims (4)

A supercharging passage provided with an electric supercharger; a bypass passage connected to an upstream side of the electric supercharger in the supercharging passage and provided with an intake control valve; and the supercharging passage and the bypass A junction passage extending downstream from a junction with the passage and provided with a throttle valve, and supplying electric power to the electric supercharger when the engine is in a predetermined supercharging region. An engine supercharging device configured to stop power supply to the supercharger when in a non-supercharging region set on a lower load side than the supercharging region,
Closing the intake control valve when the operating state of the engine shifts from the non-supercharged region to the supercharged region, and then starting to supply power to the electric supercharger when a predetermined period has elapsed. The engine supercharger. The engine supercharging device according to claim 1,
Having a supercharger rotational speed detection means for detecting the actual rotational speed of the electric supercharger
When the operating state of the engine shifts from the non-supercharged region to the supercharged region and power supply to the electric supercharger is started, the actual state immediately before the start of power supply to the electric supercharger detected by the detection means is detected. A supercharging device for an engine, characterized in that the larger the difference between the rotational speed and the target rotational speed at the time of supercharging, the larger the electric power supplied to the supercharger. The engine supercharging device according to claim 1,
When the engine operating state shifts from the supercharged region to the non-supercharged region, the power supply to the electric supercharger is stopped, and then the closing operation of the throttle valve is started when a predetermined period has elapsed. An engine supercharger characterized by the above. The engine supercharging device according to claim 3,
When the engine operating state transitions from the supercharged region to the non-supercharged region, the power supply to the electric supercharger is stopped, and then the opening operation of the intake control valve is started when a predetermined period has elapsed. An engine supercharger characterized by being made to cause.

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