JP2009243268A - Motor driven supercharger control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driven supercharger control device for improving drivability while minimizing the lowering of torque during the operating restriction of a motor. <P>SOLUTION: The motor driven supercharger control device includes a motor driven supercharger mounted in an intake passage for an internal combustion engine for applying pressure on intake air in the intake passage, and a determining means for determining whether there is an acceleration request from a driver or not. When the operating temperature of the supercharger is higher than a second predetermined temperature T2, even if the acceleration request is determined, the operation of the supercharger is restricted. When the acceleration request is determined again during restricting the operation of the supercharger, if the operating temperature of the supercharger is lower than a first predetermined temperature T1, the operating restriction of the motor is cancelled. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine provided with an electric supercharger that performs supercharging according to the operating state of the internal combustion engine.

2. Description of the Related Art Conventionally, a turbocharger has been provided with a compressor that supercharges intake air in an intake passage of an internal combustion engine (engine), and this compressor is operated by the energy of exhaust gas to increase the amount of intake air to improve engine torque. (Exhaust turbochargers) are widely used.
In recent years, various types of electric superchargers or electric compressors in which the compressor is driven by a motor have been proposed in addition to those utilizing the energy of the exhaust gas.

An engine equipped with such a supercharging system using an electric compressor is generally provided with an electronically controlled throttle valve as a throttle valve, and the actuator of this throttle valve and the motor of the electric compressor are integratedly controlled. Yes.
For example, when the accelerator position sensor detects the accelerator depression amount (accelerator opening) of the driver, the electronic control unit (ECU) calculates the intake air amount required for the engine based on the detected accelerator opening information. At the same time, the rotational speed of the compressor and the opening of the throttle valve are calculated so as to meet the required intake air amount. Based on these calculation results, the ECU outputs a control signal to the motor of the electric compressor and the actuator of the throttle valve to control the amount of intake air taken into the engine.

  A bypass passage that bypasses the electric compressor is provided upstream of the throttle valve. And when supercharging to the engine is necessary, the electric compressor is operated without using the bypass passage to perform supercharging, and when supercharging to the engine is not necessary (when naturally aspirating or NA), the electric compressor The natural intake from the bypass passage is performed without operating (or idling).

In addition to such an electric supercharger, for example, in Patent Document 1 below, a hybrid supercharger of an exhaust turbocharger and an electric supercharger that assists the operation of the exhaust turbocharger with a motor. Technology related to the machine is disclosed.
JP 2006-299883 A

  By the way, in the electric supercharger as described above, when the motor is continuously operated at a high speed, the temperature of the bearing that supports the motor winding and the rotating shaft of the compressor rises, and the durability may be lowered. For this reason, the ECU constantly monitors the temperature of the motor winding and the shaft bearing, and if the temperature exceeds the judgment value, it limits the operation of the motor (the compressor speed is extremely low, that is, the motor is idled). This reduces the temperature of the turbocharger.

Also in the above Patent Document 1, a technique for reducing the output of the motor when the motor temperature exceeds a limit value is disclosed, thereby protecting the motor and reducing the temperature. .
However, when the operation of such a motor is limited, the supercharging pressure is not applied even if the engine operating region is in the supercharging region, and the state becomes the non-supercharging state. Therefore, when the motor operation is restricted, there is a problem that even if the driver requests acceleration, the requested torque cannot be output and the acceleration performance is impaired.

  The present invention was devised in view of such problems, and provides a control device for an electric supercharger that suppresses torque reduction at the time of motor operation restriction as much as possible to improve drivability. With the goal.

  For this reason, the control device for the electric supercharger according to the present invention is installed in the intake passage of the internal combustion engine and detects a required load on the internal combustion engine and a motor-driven supercharger that pressurizes the intake air in the intake passage. A load sensor, a determination means for determining the degree of acceleration request of the driver based on information from the load sensor, a temperature sensor for detecting the temperature of the supercharger including the motor, and the temperature sensor Motor operation control means for restricting the operation of the motor when the temperature becomes equal to or higher than an operation restriction temperature for restricting the operation of the supercharger, and the motor operation control means includes an acceleration determined by the determination means. The operation limit temperature is made variable based on the degree of demand (claim 1).

  The motor operation control means has a first predetermined temperature and a second predetermined temperature set lower than the first predetermined temperature by a predetermined temperature as the operation limit temperature, and from the temperature sensor If the operating temperature of the supercharger becomes equal to or higher than the second predetermined temperature, the supercharger operation is restricted even when the acceleration request is determined, and the supercharger is restricted when the operation temperature is limited. When the acceleration request degree is determined, it is preferable to release the motor operation restriction on condition that the operating temperature of the supercharger is lower than a first predetermined temperature.

Further, it is preferable that the motor operation control means causes the motor to perform an idle operation when the operation of the motor is limited.
In addition, a temperature region provided between the first predetermined temperature and the second predetermined temperature, that is, a limit allowance is set based on a difference between a temperature increase rate and a temperature decrease rate of the supercharger. Preferred (claim 4).

  According to the control device for the electric supercharger of the present invention, when it is determined that the operating temperature of the supercharger is higher than the second predetermined temperature, the operation of the supercharger is limited even if there is an acceleration request. The machine can be protected and the temperature can be lowered. Even in such a situation, when the acceleration request is determined again, the motor is operated under the condition that the operating temperature of the supercharger is lower than the first predetermined temperature higher than the second predetermined temperature. Since the operation restriction is released, it is possible to avoid a decrease in torque accompanying the restriction of the operation of the supercharger, and the acceleration performance is not impaired. Therefore, it is possible to improve drivability while suppressing torque reduction when the motor operation is limited as much as possible.

Hereinafter, a control device for an electric supercharger according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an overall configuration thereof.
In FIG. 1, 9 indicates an engine mounted on the vehicle. An intake passage 1 is connected to the engine 9, and an electric compressor (electric supercharger) 3 and an electronically controlled throttle valve 4 are interposed in the intake passage 1. An air cleaner 8 for removing dust in the air sucked into the engine 9 is provided upstream of the electric compressor 3.

  In addition to the above-described electric compressor 3 and the like, an ECU (electronic control unit) 20 as control means for controlling the operation of the electric compressor 3 and the throttle valve 4 and the driving power of the electric compressor 3 are provided around the engine 9. A battery 10 to be supplied, an accelerator position sensor 7 as a load sensor for detecting the depression amount of the accelerator pedal 6 by the driver, an engine speed sensor (engine speed detecting means) 13 for detecting the speed of the engine 9, and an intake passage An intake pressure sensor (referred to as an intake manifold pressure sensor or a manifold pressure sensor) 12 for detecting the actual intake pressure is provided.

  Among these, the accelerator position sensor 7 is interposed in the vicinity of the accelerator pedal 6, detects the amount of depression of the driver's accelerator pedal 6 (accelerator opening information), and outputs this detection information to the ECU 20 described later. It has become. The accelerator opening information detected by the accelerator position sensor 7 is treated as a parameter representing the output requested by the driver from the vehicle. That is, it is determined whether or not the driver is accelerating the vehicle (acceleration determination) from the time change amount (time increase amount) of the accelerator opening information. The accelerator opening information is detected as one of the parameters indicating the load state of the engine 9, and in particular, in this embodiment, the accelerator opening is used as the engine load.

  In this embodiment, a throttle position sensor 5 that detects the opening of the throttle valve 4 is provided. The valve opening information of the throttle valve 4 detected by the throttle position sensor 5 is output to the ECU 20. Further, the engine speed sensor 13 detects information on the number of revolutions of the engine 9, and this speed information is outputted to the ECU 20.

  The opening degree of the throttle valve 4 provided in the intake passage 1 of the engine 9 is controlled based on a control signal from the ECU 20, thereby adjusting the amount of intake air taken into the engine 9. It has become so. In addition, the intake air amount sucked into the engine 9 is calculated based on accelerator opening information detected by the accelerator position sensor 7 in the ECU 20.

  The electric compressor 3 is provided upstream of the throttle valve 4 so that intake air can be supercharged as necessary. Further, whether or not supercharging is necessary is determined by a map (see FIG. 2) stored in the ECU 20. Specifically, the compressor 3 is operated depending on whether the current operation state determined by the accelerator opening and the engine speed is in a supercharging region or a non-supercharging region (NA region) set in advance on the map. Or not is determined.

Further, the electric compressor 3 includes an electric motor (electric motor) 31 and a compressor main body 32, and the compressor main body 32 rotates integrally with the motor 31 being driven to rotate. The driving power of the electric motor 31 is supplied from the battery 10 via the supercharger driver 11.
When the ECU 20 determines that the engine operating state is in the supercharging region, the ECU 20 obtains a required supercharging pressure based on the accelerator opening, and the electric motor 31 of the electric motor 31 through the supercharger driver 11 so as to obtain the required supercharging pressure. The operating rotational speed is controlled. The supercharger driver 11 controls the rotational speed of the electric motor 31 by controlling the current from the battery 10. Further, the rotational speed of the motor 31 is feedback controlled based on information from an intake pressure sensor 12 described later.

The motor 31 is provided with a motor temperature sensor 33 that detects the temperature of the motor. In this embodiment, the motor temperature sensor 31 is attached to a housing (not shown) of the motor 31 and is configured to detect the housing temperature of the motor 31. The temperature information detected by the temperature sensor 31 is output to the ECU 20.
In place of the temperature sensor 33 as described above, means for detecting or estimating the temperature of a place where the motor 31 is likely to become hot during continuous operation, such as a winding of the motor 31 and a shaft bearing (both not shown), are provided. Also good. Further, the overall operating temperature of the compressor (supercharger) 3 may be detected or estimated.

  Further, a bypass passage 14 for bypassing the electric compressor 3 is provided upstream of the throttle valve 4 in parallel with the electric compressor 3, and the reed valve 2 is interposed on the bypass passage 14. Thus, when the engine 9 needs to be supercharged, the intake air is supercharged via the electric compressor 3 described above, while when the engine 9 does not need to be supercharged (that is, during natural intake), the electric compressor Natural intake is performed through the reed valve 2 without the operation of 3. The reed valve 2 is configured as a one-way valve that allows only the flow of intake air to the engine 9 and prohibits the reverse flow.

  When supercharging is not required (during natural intake), the compressor 3 is not completely stopped, but is maintained in an idle operation state at a predetermined rotation speed (for example, about 5000 rpm). The predetermined rotational speed in the idling state is set to a rotational speed as high as possible within a range where no boost pressure is generated (0 boost), and intake air is supplied to the engine 9 at a negative pressure generated by the lowering of the piston. Then, by performing idle operation without stopping the motor 31 during operation in the non-supercharging region, the rotational speed of the compressor main body 32 is quickly increased when the engine operating state shifts to the supercharging region due to depression of the accelerator. Therefore, the delay in the rise of the supercharging pressure (turbo lag) can be greatly reduced.

  An intake pressure sensor (intake manifold pressure sensor) 12 is a sensor that detects an intake pressure in the vicinity of a surge tank (not shown) in the intake passage 1 or an intake manifold, and is a sensor that detects the pressure of the intake air actually supplied to the engine 9. is there. Therefore, since the supercharging pressure (boost pressure) of the supercharged intake air is detected when the electric compressor 3 is operating, the intake pressure sensor 12 is referred to as a supercharging pressure sensor (boost pressure sensor). You can also.

Further, the ECU 20 performs feedback control on the supercharging pressure of the electric compressor 3 based on the supercharging pressure detected by the intake pressure 12.
Next, the configuration of the main part of the present apparatus will be described. Detection information of various sensors such as the throttle position sensor 5, the accelerator position sensor 7, the intake pressure sensor 12, the engine speed sensor 13 and the motor temperature sensor 33 described above is sent to the ECU 20. It is input and processed.

The ECU 20 includes a determination unit (determination unit) 21, a calculation unit (air-fuel ratio setting unit) 22, a motor control unit (motor operation control unit) 23, and a throttle valve control unit 24.
Among these, the determination part 21 is based on the information from the accelerator position sensor 7 as a load sensor, and the information from the engine speed sensor 13, and the operating state of the engine 9 is the supercharging area which supercharges intake air, or supercharging. A non-supercharging region that is not to be determined is determined, and is provided as a map having the accelerator opening and the engine speed as parameters as shown in FIG.

If the operating point obtained from the accelerator opening and the engine speed is above the 0 boost line (high load side) shown in the map of FIG. 2, the motor 31 is driven to operate the compressor 3. It has become. That is, in this case, since the required torque cannot be output by natural intake, the compressor 3 is operated to ensure the output torque.
Further, if the operating point obtained from the accelerator opening and the engine speed is below the 0 boost line (low load side), the natural intake region (NA region) is entered, and the compressor 3 is in idle operation. That is, in this case, since it is an operating range in which sufficient output torque can be secured without supercharging, the compressor 3 is in an operating state in which it is not supercharged as an idle operation. In this case (in the case of the non-supercharged region), naturally, no supercharging pressure is applied, so that it can be regarded as an engine without a supercharger (naturally-intake engine or NA engine).

  The calculation unit 22 calculates the target boost pressure Pt, the required intake air amount Qt, and the target rotational speed Nt of the motor 9 based on information from the accelerator position sensor 7 as a load sensor. More specifically, when the determination unit 21 determines that the engine 9 is in the supercharging region, the required intake air amount Qt is calculated based on a supercharging map (not shown), and the target supercharging is calculated from the required intake air amount Qt. The pressure Pt is obtained. Further, when the target boost pressure Pt is obtained, the target rotational speed Nt of the motor 31 is calculated based on the target boost pressure Pt. Further, feedback information from the intake pressure sensor 12 is added to the target rotational speed Nt. The setting method and calculation method of the required intake air amount Qt, the target boost pressure Pt, and the target rotation speed Nt are not particularly limited, and can be determined by various known methods.

  In addition to this, the calculation unit 22 has a function of setting a target air-fuel ratio (A / F) for the engine 9. Here, the calculation unit 22 sets the target air-fuel ratio based on the load (accelerator opening) and the engine speed. When the target air-fuel ratio is set by the calculation unit 22, the set target air-fuel ratio is set. The drive time of an injector (not shown) is set so that the air-fuel ratio is obtained.

  When the target boost pressure Pt, the required intake air amount Qt, the target rotational speed Nt of the motor 31 and the target air-fuel ratio of the engine 9 are obtained in the calculation unit 22 as described above, the motor control unit 23 of the ECU 20 calculates the above-described calculation. A current value for the motor 31 is obtained from the target rotational speed Nt calculated by the unit 22, and a control signal for the driver 11 is output so that this current value is obtained. And the operating rotational speed of the compressor 3 is controlled by such control.

Further, the throttle valve control unit 24 sets the throttle opening of the throttle valve 4 according to the depression amount of the accelerator pedal of the driver, and an actuator (not shown) of the throttle valve 4 so as to become the set throttle opening. The operation of is controlled.
Further, the ECU 20 obtains an injector drive pulse (not shown) from the intake air flow rate and the target air-fuel ratio, and outputs an operation control signal for the injector so as to execute fuel injection with this drive pulse.

Meanwhile, the motor control unit 23 is configured to limit the operation of the motor 31 based on the motor temperature Tm obtained from the motor temperature sensor 33. Here, the motor control unit 23 stores in advance a first predetermined temperature T1 and a second predetermined temperature T2 (<T1) as thresholds relating to the motor temperature Tm (see FIG. 3).
Among these, the first predetermined temperature T1 is a threshold value on the high temperature side, and is a temperature at which stable operation of the motor 31 such as seizure of the bearing of the motor 31 cannot be secured if the motor 31 is used at a higher temperature. Therefore, when it is determined that the motor temperature Tm is in the temperature range equal to or higher than the first predetermined temperature T1, the operation of the motor 31 is limited without exception. In this case, the motor 31 is forcibly controlled to idle operation.

The second predetermined temperature T2 is a threshold set lower than the first predetermined temperature T1 by a predetermined temperature, and is set as T2 = T1 (fixed value) −limit allowance. A specific method for obtaining the restriction fee will be described later.
Here, the second predetermined temperature T2 is provided for the purpose of reliably preventing the temperature of the motor 31 from reaching the first predetermined temperature T1. Therefore, when the motor temperature Tm becomes equal to or higher than the second predetermined temperature T2, the operation of the motor 31 is basically restricted and controlled to idle operation.

  In addition to this, a third predetermined temperature T3 (<T1) is provided as a low temperature side threshold. Here, T3 is a temperature of, for example, 0 ° C. or less, and is set assuming an operation at an extremely low temperature. It is conceivable that the motor 31 is frozen and does not operate at such a low temperature, and if a load is applied forcibly, the motor 31 may be damaged. Therefore, the motor 31 is limited in such a range that is less than the low temperature side threshold value T3.

That is, the motor controller 23 protects the motor 31 by prohibiting (stopping) the operation of the motor 31 when it is determined that the motor temperature Tm <T3. Therefore, in this case, the engine 9 functions as a naturally aspirated engine.
When the driver depresses the accelerator and the acceleration request is determined in the determination unit 21, the motor control unit 23 refers to the motor temperature Tm if the operation region is the supercharging region, and as shown in FIG. If the temperature of 31 is within the temperature range of T3 ≦ Tm <T2, since it is within the allowable operating temperature range of the motor 31, supercharging is performed without restricting the operation of the motor 31. In the present embodiment, it is determined that there is an acceleration request when the change rate of the accelerator opening detected by the accelerator position sensor 7, that is, the degree of the acceleration request is equal to or greater than a predetermined value.

Further, when it is determined that Tm ≧ T2, the operation of the motor 31 is restricted and the idling operation is forcibly performed. In this case, the motor 31 is idled to prevent further temperature rise and to reduce the motor temperature.
However, once it is determined that Tm ≧ T2, if the engine operating state enters the supercharging region again due to an acceleration request, in this case, even if the motor temperature Tm is equal to or higher than the second predetermined temperature T2, the first predetermined temperature If it is less than T1 (that is, if Tm <T1 is satisfied), the operation restriction of the motor 31 is canceled and supercharging is performed.

  As described above, the first predetermined temperature T1 is a temperature provided to reliably prevent the motor 31 from being damaged or the like, whereas the second predetermined temperature T2 is the first predetermined temperature. Since this is a threshold value that takes into account a predetermined limit for T1, even if the motor temperature Tm is equal to or higher than T2, if it is in the temperature range below T1, it is temporarily activated such as a request for acceleration again. In response to the request, the operation of the motor 31 can be allowed.

  Therefore, in this case, it is determined that there is no problem in the temporary operation of the motor 31 and the operation restriction of the motor 31 is released, so that the torque reduction at the time of motor operation restriction is suppressed as much as possible. It is trying to improve the ability. Even when the operation restriction of the motor 31 is canceled, when the temperature Tm of the motor 31 exceeds the first predetermined temperature T1, the operation immediately shifts to idle operation, and thereafter forced until it becomes less than T2. It is designed to keep idle operation.

  Next, a method for setting the limit allowance and the second predetermined temperature T2 will be described. Here, the second predetermined temperature T2 is determined based on the speed difference between the temperature increase and the temperature decrease of the supercharger 3. The temperature increase rate of the motor 31 is determined by the current, and the temperature increase rate of the bearing shaft (not shown) is determined by the rotational speed of the compressor 32. Both can be obtained from the intake air amount and the pressure ratio of the supercharger 3. Further, since the supercharger 3 is cooled by intake air, the temperature lowering speed can be obtained from the intake air flow velocity measured by an air flow sensor (not shown).

From the above, the limit allowance can be obtained using the following equation. In the following equation, k1 and k2 are both coefficients.
Second predetermined temperature T2 = first predetermined temperature T1−k1 × (motor current or compressor rotation speed) + k2 × (intake flow velocity)
That is, if the motor current or the compressor speed increases, the temperature rises faster, so it is necessary to limit the temperature early, and the second predetermined temperature T2 is set low. In addition, if the intake air flow rate is fast, the temperature drop due to the removal of the heat quantity of the intake air increases, so the predetermined temperature T2 can be set high. When the second predetermined temperature T2> the first predetermined temperature T1 is satisfied according to the above formula, it is necessary to set the second predetermined temperature T2 = the first predetermined temperature T1.

Since the control device for the electric supercharger according to one embodiment of the present invention is configured as described above, its operation will be described below with reference to the flowchart of FIG.
First, in step S1, it is determined whether or not the engine operating state has exceeded the 0 boost line (see FIG. 2) and has entered the supercharging region from the non-supercharging region based on the accelerator opening and the engine speed. Here, if the 0 boost line is not exceeded from the non-supercharged area, the process returns. If it is determined that the 0 boost line is exceeded, the process proceeds to step S2.

In step S2, it is determined whether or not the motor temperature Tm is equal to or higher than the third predetermined temperature T3 and lower than the second predetermined temperature T2 (see FIG. 3). If the motor temperature Tm is within the above range, the temperature of the motor 31 is within the allowable temperature range, so that the operation of the supercharger 3 is permitted in step S8 (that is, the operation of the motor 31 is permitted). ).
If it is determined in step S2 that the temperature of the motor 31 is not within the above range, the process proceeds to step S3, where it is determined whether the motor temperature Tm is equal to or higher than a second predetermined temperature T2. If the motor temperature Tm is equal to or higher than the second predetermined temperature T2, the process proceeds to step S4, and if not, the process proceeds to step S9.

  Here, when the process proceeds to step S9, the motor temperature Tm is an extremely low temperature lower than the third predetermined temperature T3. In this case, the supercharger is considered in consideration of freezing of the motor shaft and the like. 3 operation is limited. That is, in this case, the operation of the motor 31 is stopped. On the other hand, when the process proceeds to step S4, the motor temperature Tm is equal to or higher than the second predetermined temperature T2, and in this case, the motor 31 is limited to idle operation in step S4.

  Then, after the process of step S4, it is determined whether or not an acceleration request has been made again in step S5, and if there is no reacceleration request, the process directly returns. If there is a reacceleration request, the process proceeds to step S6, and it is determined whether or not the motor temperature Tm is lower than the first predetermined temperature T1. Here, if the motor temperature Tm is lower than the first predetermined temperature T1, the process proceeds to step S7 to permit the operation of the motor 31, that is, to release the operation restriction of the motor 31, and if the motor temperature Tm is equal to or higher than the first predetermined temperature T1, Return as is. In this case, the idle operation of the motor 31 is maintained.

  As described above, according to the control device for the electric supercharger according to the embodiment of the present invention, the limit allowance is higher than the high temperature region (the temperature region of the first predetermined temperature T1 or higher) in which the motor 31 may be damaged. In consideration of the above, the second predetermined temperature T2 is set on the low temperature side, and once the motor temperature Tm becomes equal to or higher than T2, the idling operation is performed once, so that the motor temperature Tm can be reliably set before reaching the first predetermined temperature T1. The reduction can be achieved, and the durability of the motor 31 can be improved while avoiding damage to the motor 31. Further, when the driver depresses the accelerator again (when the acceleration request is determined again), the restriction on the operation of the motor 31 is released on condition that the temperature of the motor 31 is lower than the first predetermined temperature T1. The torque required by the driver can be ensured while avoiding damage to the motor 31, and a decrease in acceleration performance can be avoided.

In addition, this device can be realized with a simple configuration in which only the control logic is changed without adding new parts or devices to the control device for the conventional electric supercharger, which may increase the cost. It also has the advantage of not.
Next, a modification of the embodiment of the present invention will be described with reference to FIG. In the above-described embodiment, as the temperature region on the high temperature side that restricts the operation of the motor 31, the first predetermined temperature T1 that restricts the operation of the motor 31 to idle operation without exception even when the engine 9 enters the supercharging region at the time of an acceleration request. Although the above temperature range and the operation of the motor 31 are basically limited to the idle operation, the operation of the motor 31 is performed on the condition that when the acceleration request is made again, the motor temperature Tm is lower than the first predetermined temperature T1. In contrast to the provision of two temperature regions, the second predetermined temperature T2 and the temperature region lower than the first predetermined temperature T1 for releasing the restriction, in this modification, the temperature is further decreased to be lower than the second predetermined temperature T2. It is characterized by the addition of a temperature region. In this modified example, as shown in FIG. 5, two temperature regions are set below the second predetermined temperature T2, but the number of such additional temperature regions may be one or three or more. .

As shown in FIG. 5, in this modification, a fourth predetermined temperature T4 (<T2) and a fifth predetermined temperature T5 (<T4) are set, and the fourth predetermined temperature T5 is equal to or higher than the fifth predetermined temperature T5. A temperature region having a temperature less than a predetermined temperature T4 and a temperature region having a temperature equal to or higher than a fourth predetermined temperature T4 and less than a second predetermined temperature T2 are provided.
Then, when the temperature of the motor 31 is in these temperature ranges, the following control is executed.

First, when the driver depresses the accelerator and makes an acceleration request to enter the supercharging region, the motor control unit 23 takes in the motor temperature Tm. If the motor temperature Tm is in the temperature range of T3 ≦ Tm <T5, the calculation unit 22 The operation of the motor 31 is controlled so that the calculated target rotation speed Nt of the motor 31 is obtained. That is, in this case, the operation of the motor 31 is not limited.
If the motor temperature Tm is in the temperature range of T5 ≦ Tm <T4, the motor 31 is limited by a predetermined ratio (for example, 30%) with respect to the target rotational speed Nt calculated by the calculation unit 22. Reduces temperature rise. That is, in this case, in the motor control 23, a value obtained by multiplying the target rotational speed Nt of the motor 31 calculated by the calculation unit 22 by the coefficient 0.7 is newly set as the target rotational speed, and is output to the motor 31. It is like that.

Further, when the driver further requests acceleration and enters the supercharging region, if Tm <T4, the operation restriction of the motor 31 is released and the compressor 3 is operated. As a result, the driver's required torque is output to maintain acceleration performance.
On the other hand, if the driver requests acceleration and enters the supercharging range, and the temperature Tm of the motor 31 at this time is within the temperature range of T4 ≦ Tm <T2, the target rotational speed of the motor 31 calculated by the calculation unit 22 By further restricting Nt (for example, 50%), the temperature increase of the motor 31 is suppressed.

In this case, in the motor control 23, a value obtained by multiplying the target rotational speed Nt of the motor 31 calculated by the arithmetic unit 22 by a coefficient 0.5 is newly set as the target rotational speed, and is output to the motor 31. It has become.
Further, when a re-acceleration request is received from the driver and the engine enters the supercharging region, if Tm <T2, the operation restriction of the motor 31 is canceled and the compressor 3 is operated, thereby outputting the driver's required torque. The acceleration performance is maintained.

As described above, by further adding a temperature region that restricts the operation of the motor 31 and further restricting the operation of the motor 31, appropriate temperature management of the motor 31 and prevention of a decrease in output torque can be achieved.
In the above-described embodiment, when the degree of the predetermined acceleration request is determined while the turbocharger is restricted by the second predetermined temperature T2, the release is performed within the range of the restriction by the first predetermined temperature T1. The limit temperature may be varied from the beginning according to the degree of acceleration request. For example, the operation of the motor may be limited at a first predetermined temperature T1 or higher when the degree of acceleration request is large, and the motor operation may be limited at a second predetermined temperature T2 or higher when the degree of acceleration request is small. . Moreover, you may make it change continuously the temperature which restrict | limits the action | operation of a motor according to the acceleration request | requirement degree.

  As mentioned above, although embodiment of this invention and its modification were demonstrated, this invention is not limited to the above-mentioned embodiment and modification, A various deformation | transformation is possible in the range which does not deviate from the meaning of this invention. . For example, the type of the electric compressor 3 is not particularly limited as long as the electric compressor 3 compresses and supercharges intake air by the motor 31.

It is a schematic diagram which shows the whole structure of the control apparatus of the electric supercharger concerning one Embodiment of this invention. It is a figure for demonstrating the supercharging characteristic of the control apparatus of the electric supercharger concerning one Embodiment of this invention. It is a figure for demonstrating the operation characteristic regarding the supercharger temperature in the control apparatus of the electric supercharger concerning one Embodiment of this invention. It is a flowchart for demonstrating an effect | action of the control apparatus of the electric supercharger concerning one Embodiment of this invention. It is a figure explaining the modification of the control apparatus of the electric supercharger concerning one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intake passage 2 Reed valve 3 Supercharger 4 Throttle valve 5 Throttle position sensor 6 Accelerator pedal 7 Accelerator opening sensor (load sensor) constituting actual intake air amount detecting means
9 Engine (Internal combustion engine)
12 Intake Pressure Sensor Constructing Actual Intake Amount Detection Unit 13 Engine Speed Sensor 21 Determination Unit (Determination Unit)
22 Calculation unit (air-fuel ratio setting means)
23 Motor controller (motor operation control means)
24 Throttle valve control unit (Throttle valve operation control means)
31 Motor 32 Compressor body 33 Motor temperature sensor (temperature sensor)

Claims (4)

A motor-driven supercharger interposed in the intake passage of the internal combustion engine and pressurizing the intake air in the intake passage;
A load sensor for detecting a required load on the internal combustion engine;
Determining means for determining the degree of acceleration request of the driver based on information from the load sensor;
A temperature sensor for detecting a temperature of the supercharger including the motor;
Motor operation control means for limiting the operation of the motor when the temperature detected by the temperature sensor becomes equal to or higher than the operation limit temperature for limiting the operation of the supercharger;
The motor operation control means includes:
A control device for an electric supercharger, characterized in that the operating limit temperature is variable based on the degree of acceleration request determined by the determination means. The motor operation control means includes:
A first predetermined temperature as the operation limit temperature and a second predetermined temperature set to a lower temperature side by a predetermined temperature than the first predetermined temperature;
Based on the information from the temperature sensor, when the operating temperature of the supercharger is equal to or higher than a second predetermined temperature, the operation of the supercharger is limited even if the acceleration request is determined,
When a predetermined acceleration request level is determined when the supercharger is limited, the motor operation limit is canceled on the condition that the operating temperature of the supercharger is lower than a first predetermined temperature. A control device for an electric supercharger. The control device for an electric supercharger according to claim 1 or 2, wherein the motor operation control means causes the motor to perform an idle operation when the operation of the motor is limited. The temperature region provided between the first predetermined temperature and the second predetermined temperature is set based on a difference between a temperature increase rate and a temperature decrease rate of the supercharger. The control apparatus of the electric supercharger of any one of 1-3.

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