JP2005180255A - Power train control device provided with electric supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent or eliminate insufficient electric power supply at a time of small intake air density. <P>SOLUTION: Operation states of an engine are divided into a first zone X where natural aspiration operation of the engine 1 is performed, a second zone Y where supercharged operation (drive assist by supercharging) by an electric supercharger 5 is performed, and a third zone Z where drive assist with making a motor generator 11 function as a motor is performed in addition to supercharging operation by the electric supercharger 5 with setting engine speed and target torque as engine load as parameters. For example, the motor generator 11 functions as a generator and generated electric power is charged in a charging device 15 at a time of the operation state in the first zone X. Target charging quantity of the charging device 15 is normally set to small value, for example 80%, from a viewpoint to perform sufficient charging at a time of regenerative braking. On the other hand, the target charging quantity is changed to large value, for example 90%, at a time of traveling in an area of small intake air density such as highland. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a control device for a vehicle including an engine with an electric supercharger, more specifically, an electric supercharger for increasing the output of the engine, and a motor that functions as a power source for the vehicle, The present invention relates to a control apparatus for a power train provided with an electric supercharger configured to switch these drives in accordance with an operating state of an engine.

  Conventionally, superchargers and turbochargers have been well known as means for increasing engine output, but both have the problem of insufficient supercharging pressure in the low engine speed range as a result of the supercharging capacity being greatly affected by the engine speed. There is. In contrast, an electric supercharger that drives a compressor with a motor can control the rotation speed of the compressor without being affected by the rotation speed of the engine, so that it can generate a sufficient boost pressure even in a low rotation speed region. Have.

  On the other hand, in recent years, environmentally friendly vehicles equipped with a motor that functions as a power source of the vehicle in addition to the engine have been known. For example, Patent Document 1 discloses a combination of such a motor and the electric supercharger. An engine is disclosed. However, Patent Document 1 discloses a motor generator (motor generator) that has a function as a power source of a vehicle and a function as a generator that is driven by an engine and generates power as a motor. .

  And, in this way, in a vehicle equipped with an electric supercharger that increases engine output and a motor generator, for example, rotation-related values such as engine speed and vehicle speed, accelerator opening, etc. Each region indicating the driving state of the electric supercharger and the motor generator is set in a map according to the operating state of the engine using a torque related value such as a representative engine load as a parameter. The engine output control is performed by applying the engine speed, the engine load, etc., and switching the driving of the electric supercharger and the motor generator according to the result.

  In this regard, according to Patent Document 1, as shown in FIG. 27, the low vehicle speed (low rotation) low load region is a motor travel region in which the vehicle travels only with the output of the motor, and the medium vehicle speed (medium rotation). The medium load region is a non-supercharging region where the vehicle is driven only by the output of the natural intake of the engine, the low vehicle speed (low rotation) high load region is a supercharging region for driving the electric supercharger, and The medium vehicle speed (medium rotation) high load region to the full vehicle speed (high rotation) region are motor assist regions that drive the motor in addition to the electric supercharger.

  On the other hand, a vehicle including an electric supercharger includes a power storage device that serves as a power supply source for the motor generator to function as a drive assist motor or when the motor generator functions as a drive assist motor. When the vehicle decelerates, it is generally performed that the motor generator functions as a generator to store electric power in the power storage device (regenerative braking). Has also been done. A large battery may be used as the power storage device, but a capacitor (capacitor) type that can charge and discharge a large amount of power with high response is often used.

The power storage device as described above is generally controlled so as to achieve the target power storage amount, but considering that regenerative braking is performed when the vehicle decelerates (when the motor generator functions as a generator) The target power storage amount is set to a storage amount smaller than the fully charged (power storage) state, for example, 80% instead of 100%.
Japanese Patent Laid-Open No. 11-332015 (FIG. 2)

  As described above, in a vehicle including an electric supercharger, a motor generator, and a power storage device, a large torque can be obtained when necessary by controlling the operating state of the electric supercharger or the motor generator. As a result, the fuel consumption can be greatly improved, and the future is expected as an environmental power train.

  On the other hand, when the frequency with which the electric supercharger or the motor generator functions as drive assist increases, the amount of discharge is greater than the amount of charge to the power storage device, and the power supply from the power storage device may be insufficient. Arise. In particular, when driving on high altitudes, the intake density is small (low) and the engine output tends to decrease, so the amount of accelerator depression tends to increase. As a result, it is driven by an electric supercharger or motor generator. There are many opportunities for assistance, and power supply from the power storage device tends to be insufficient. When the power supply from the power storage device is insufficient, it is further promoted that the accelerator is depressed because the drive assist is insufficient, and the tendency to cause further power shortage becomes stronger.

  Increasing the target power storage amount of the power storage device to solve the above power shortage may be considered, but increasing the target power storage amount constantly increases the chances that regenerative braking cannot be performed sufficiently. It is difficult to adopt.

  The present invention has been made in view of the above circumstances, and prevents power supply shortage when the intake air density is small in the case where power is supplied from the power storage device to the electric supercharger and the motor generator. Another object of the present invention is to provide a powertrain control device including an electric supercharger that can be reduced.

In order to achieve the above object, the following solution is adopted in the present invention. That is, as described in claim 1 in the claims,
A motor generator that is connected to an engine serving as a drive source for vehicle travel, and that selectively performs a function as a travel motor that assists the driving force of the engine and a function as a generator driven by the engine;
An electric supercharger for supercharging the intake air of the engine;
A power storage device that stores power generated by the motor generator and serves as a power supply source for the motor generator and the electric supercharger;
Load detection means for detecting parameters relating to engine load;
A rotational speed detecting means for detecting a parameter relating to the engine rotational speed;
An intake air density detecting means for detecting a parameter related to the intake air density;
Control means for controlling the motor generator and the electric supercharger based on the engine load detected by the load detection means and the engine rotation detected by the rotation speed detection means;
With
The control unit controls the power storage amount of the power storage device to be a target power storage amount, and when the intake air density detected by the intake air density detection unit is small, the target power storage amount is higher than when the intake air density is large. It is set to perform control to change the amount of stored electricity to a large value,
It is like that.

  According to the above solution, when the intake density is small and the frequency (opportunity) of driving assistance by the electric supercharger or motor generator increases, the target power storage amount of the power storage device is increased to supply power to the power storage device. Since power storage is sufficiently performed, the shortage of power supplied from the power storage device is prevented or reduced.

A preferred mode based on the above solution is as described in claim 2 and the following claims. That is,
A winding road detecting means for detecting that the traveling road surface is a winding road;
The control means is set to correct the target power storage amount to a larger value when a winding path is detected by the winding path detection means than when a winding path is not detected.
(Claim 2). The winding road tends to increase the frequency of driving assistance by an electric supercharger or motor generator compared to a straight road. However, when traveling on this winding road, the target power storage amount of the power storage device is increased. Therefore, the shortage of power supplied from the power storage device is prevented or reduced.

Road type detection means for detecting whether the road is a motorway or a highway,
When the road type detection means detects that the road is an automobile-only road or an expressway, the control means sets the target storage amount to a larger value than when no automobile-only road or an expressway is detected. Set to correct,
(Claim 3). In this case, when driving on an automobile-only road or highway, the frequency of driving assistance by an electric supercharger or motor generator is higher than when driving on a general road. When traveling, the target power storage amount of the power storage device is increased, so that the shortage of power supplied from the power storage device is prevented or reduced.

  The intake density detecting means may be configured to detect the intake density based on at least one of atmospheric pressure and road altitude (corresponding to claim 4). In this case, the intake air density can be easily determined based on at least one of atmospheric pressure and road altitude.

  The target power storage amount can be set in a range not exceeding an upper limit value set to a value smaller than 100% power storage amount (corresponding to claim 5). In this case, it is possible to always leave a margin for charging the power storage device with certainty, which is preferable for reliably performing regenerative braking.

The operating region is set in advance with the engine speed and the target torque set according to the accelerator opening as parameters,
The operation region is divided into three regions: a first region where the target torque is low or high, a second region where the target torque is high and medium, and a third region where the target torque is high and low. And
The control means prohibits drive assist by the motor generator and the electric supercharger in the first region, executes drive assist only by the electric supercharger in the second region, and in the third region. It is set to control to execute the drive assist of both the motor generator and the electric supercharger,
(Corresponding to claim 6).

  In this case, problems such as knocking of the engine and surging of the electric supercharger that occur when the electric supercharger is driven in a high target torque and low rotation range are avoided. In addition, since the motor generator that assists driving is driven at a low rotation speed with a high target torque, the motor generator may be any motor generator that can be driven at a low rotation speed although it has a high torque. A small motor generator is sufficient, and the motor generator and the power storage device that supplies electric power to the motor generator can be reduced in size, so that mounting on these vehicles can be improved and the cost and size of the vehicles can be reduced. Can be planned.

  On the other hand, since the electric supercharger is driven with a high target torque and medium rotation, the torque from the low rotation region to the medium rotation region is combined with the driving of the motor generator with the high target torque and low rotation described above. The assist torque and the supercharging torque obtained by driving the motor generator and the electric supercharger can be secured. As a result, it is possible to shift the maximum torque generation speed (and the maximum output generation speed) of the engine, which can be obtained only by natural intake, to the high speed range (in other words, the torque in the high speed range is not excessive). Therefore, sufficient marginal torque (torque corresponding to the difference between engine torque and running resistance) not only in the low to medium rotation range but also in the high rotation range. Is obtained. As a result, the total gear ratio obtained from the gear ratio of the transmission and the final gear ratio can be set to a gear ratio that does not require much deceleration (a gear ratio with a small value), so that the same vehicle speed can be obtained. In this case, the engine speed can be reduced as much as the total gear ratio value is small. Therefore, the region on the lower rotation side becomes the frequently used region, and the fuel consumption is remarkably improved.

  Moreover, the shift of the maximum torque generation rotational speed (and the maximum output generation rotational speed) of the engine to a high rotational speed range can be achieved, for example, by increasing the opening time of the intake valve to increase the charging efficiency or the length of the intake passage. This is achieved by designing the engine specifications so that the inertia supercharging effect can be obtained at high revolutions. As a result, in the low-medium-rotation low-load region where the frequency of use is high, it is possible to obtain the specifications of the engine with high pumping loss, low effective compression ratio, high effective expansion ratio, and high thermal efficiency. Can improve fuel efficiency.

A first boundary characteristic line that is a boundary between the first region and the second region corresponds to a torque curve of an engine that is naturally aspirated without driving assist between the motor generator and the electric supercharger. Set to
The second boundary characteristic line that is the boundary between the second region and the third region can be set such that the target torque increases rapidly as the engine speed increases. (Corresponding to claim 7).
In this case, the setting of the first boundary characteristic line increases the frequency with which the necessary torque is obtained only by the engine that is operated by natural intake without driving assistance by the electric supercharger, that is, driving by the electric supercharger. It is preferable in terms of fuel saving by preventing the assist from being performed as much as possible. In addition, by setting the second boundary characteristic line, the drive assist in the low rotation range is performed by the motor generator as much as possible, and the problem that is likely to occur when the electric supercharger is operated in the low rotation range is more fully satisfied. This is preferable for solving the problem.

  The generation speed of the maximum torque of the engine that has been naturally aspirated without driving assist of the motor generator and the electric supercharger is set to be close to the maximum speed in the second region. (Corresponding to claim 8). In this case, it is preferable that the maximum torque generation rotation speed of the engine that is operated by natural intake operation is sufficiently shifted to the high rotation side in order to achieve sufficient fuel saving.

  As shown in FIG. 1, the vehicle according to this embodiment includes an engine 1 and a motor generator (a motor generator as a power source, a function of a motor as a power source of the vehicle, and power generation that is driven by the engine 1 to generate power). 11 which has a function as a machine) and a so-called low pollution vehicle or environment-friendly vehicle, and the crankshaft of the engine 1 and the rotating shaft of the motor generator 11 are They are interconnected by a belt or chain 12. The vehicle also has an electric supercharger 5 as means for increasing the output of the engine 1, and the supercharger 5 is disposed in the intake passage 2 of the engine 1 as a main component, for example, centrifugal. And a motor 4 that rotationally drives the compressor 3.

  Here, an intercooler 6 and an electric throttle valve 7 are arranged in this order in the intake passage 2 downstream of the compressor 3. A bypass passage (also referred to as a relief passage or a recirculation passage) 9 is provided between the upstream side of the compressor 3 and the downstream side of the intercooler 6. For example, when the flow rate of the gas passing through the compressor 3 of the electric supercharger 5 is low and the bypass passage 9 is low in rotation, in order to ensure the supercharging capability of the electric supercharger 5, the intercooler is temporarily used. For example, the gas exiting 6 is returned to the upstream side of the compressor 3 to ensure the flow rate of the gas passing through the compressor 3. The intake passage 2 is connected to the engine 1 via an intake manifold 8.

  On the other hand, the motor 4 of the electric supercharger 5 is connected to the power supply system 14 of the engine 1, the motor generator 11 is connected via an inverter 13, and a 12V lead battery 17 is connected to a DC / DC converter. The power supply system 14 is connected to the power supply system 14 through 16. When the electric supercharger 5 is driven and when the motor generator 11 is driven as a vehicle power source, power is supplied from the power storage device 15 of the power supply system 14, for example, 42V. Conversely, when the motor generator 11 is driven as a generator by the engine 1, the generated power is supplied to the power storage device 15 of the power supply system 14 via the inverter 13 and used for charging the power storage device 15. In the embodiment, the power storage device 15 is a capacitor (capacitor) type that can discharge and charge a large amount of power with high response (rapidly), but is not limited thereto. .

  In addition, power is supplied from a 12V lead battery (ordinary battery) 17 to a general electric component such as a headlight and an air conditioner, and an auxiliary starter 18 used at the time of cold start. The power of the power storage device 15 of the power supply system 14 is stepped down to 12V by the DC / DC converter 16 and is always applied.

  The control unit 50 of the engine 1 includes a signal from an accelerator opening sensor 20 that detects the opening (depression amount) of the accelerator pedal 19 by the driver, and an engine rotation sensor 21 that detects the rotation speed of the engine 1. , A signal from the navigation system 30 for setting the altitude (height) of the vehicle from the current position of the vehicle and road map information, a signal from the power supply system 14 (related to the state of the power storage device 15 such as the amount of power storage) A signal from a motor temperature sensor (for example, composed of a thermistor or the like) 22 for detecting the temperature of the motor 4 of the electric supercharger 5, an intake air temperature immediately after exiting the intercooler 6 in the intake passage 2. An intake pressure sensor 24 for detecting a signal from the intake temperature sensor 23 to be detected and an intake pressure immediately upstream of the throttle valve 7 in the intake passage 2. Et of the signal, the signal from the atmospheric pressure sensor 31 for detecting the atmospheric pressure is inputted. The control unit 50 also includes an inverter 13 for driving the motor 4 of the electric supercharger 5 and the motor generator 11 as a vehicle power source, a throttle actuator 25 for driving the throttle valve 7 and an auxiliary starter according to the result of the input signal. 18. Output various control signals to the relief valve 10 for adjusting the opening degree of the bypass passage 9 (that is, the circulation amount of the intake air passing through the compressor 3), the automatic transmission 40, etc. Then, power generation control (charge control of the power storage device 15) by the motor generator 11 is executed.

  FIG. 2 is a map for separating the operating states of the motor generator 11, the electric supercharger 5, and the engine 1 (only). The engine speed and the torque are set as parameters, and the torque as a parameter is set. Corresponds to the target torque according to the accelerator opening. That is, as will be described later, a target torque corresponding to the accelerator opening is set, and by determining which position in the map of FIG. 2 the target torque corresponding to the current engine speed is, the motor generator 11, the operation state of the electric supercharger 5 and the engine 1 (only) is appropriately selected and executed. The map shown in FIG. 2 is stored in advance in a ROM (storage means) of the control unit 50.

  In FIG. 2, it is divided into three regions of a first region X, a second region Y, and a third region Z. The first region X (non-supercharging region) is a region extending from the full low load (low torque-low target torque) to the full high rotation, and this first region X is driven only by the engine 1 that is operated by natural aspiration. It is time to perform (drive assist of the motor generator 11 and the electric supercharger 5 is not performed). The second region (supercharging region) Y is a high load and medium rotation region and is a time when drive assist is performed by the electric supercharger (no drive assist by the motor generator). The third region Z is a high load and low rotation region, and is a time when the drive assist by the motor generator 11 is performed in addition to the drive assist by the electric supercharger 5.

  The three regions X to Z will be described in more detail. A first boundary characteristic line serving as a boundary between the first region X and the second region Y is indicated by a symbol β1. This first boundary characteristic line β1 corresponds to the torque curve of the engine 1 that is operated by natural intake (in the embodiment, it is completely coincident with the torque curve of the engine 1, and also refer to FIG. 5 described later). The maximum torque generation rotation speed of the engine 1 that is operated by natural intake is set to be considerably shifted to the high rotation side as compared with the natural intake engine for ordinary passenger cars. The maximum torque generation rotational speed indicated by the first boundary characteristic line β1 is set to be near the maximum rotational speed in the second region Y where the drive assist by the electric supercharger 5 is performed. That is, the first boundary characteristic line β1 is set so that the torque (target torque) gradually increases as the rotational speed increases, but the torque increase accompanying the increase in the rotational speed is relatively gradual. As understood from the first boundary characteristic line β1, in a high load state (driving state in the second region Y) in which drive assist by the electric supercharger 5 is performed, the engine rotational speed is from a small state to a large state. As the engine speed increases, the drive assist by the electric supercharger 5 gradually increases and then the drive assist by the electric supercharger 5 increases as the engine speed increases. The rotational speed in the vicinity of the first region X that gradually decreases and shifts to the first region X where the drive assist by the electric supercharger 5 becomes extremely small becomes the substantially maximum torque generation rotational speed of the engine 1 in which only the natural intake operation is performed.

  A boundary characteristic line indicating a boundary between the second region Y and the third region Z is indicated by a symbol β2. The second boundary characteristic line β2 is set so that the torque increase increases rapidly as the engine speed increases. That is, in the third region Z, when the engine speed is small, the drive assist by the motor generator 11 becomes extremely large (which is more clearly understood by comparing with the first boundary characteristic line β1). In the third region Z, when the engine speed is low, the drive assist by the motor generator 11 is extremely large, while the drive assist by the electric supercharger 5 is extremely small. As the engine speed increases, the ratio of drive assist by the electric supercharger 5 gradually increases, and in the vicinity of the maximum speed in the third region Z, there is almost only drive assist by the electric supercharger 5.

  The line connecting the maximum torques of the three regions X to Z described above is the total maximum torque of the engine 1 with the electric supercharger 5 and the motor generator 11. This total maximum torque is the motor generator 11. Is substantially constant in the low rotation range where the drive assist is performed, and in the middle rotation range where the drive assist by the electric supercharger 5 is performed, it gradually decreases as the rotational speed increases, and only the natural intake operation of the engine 1 is performed. In the high rotation region, which is the region, the value decreases as the rotational speed increases, but the degree of decrease is greater than in the middle rotation region. However, the total maximum torque can be obtained in the normal and low rotation range and in the middle rotation range, with a substantially constant large torque, and is very easy to use (almost ideal) for automobiles. It has become.

  In FIG. 2, a more specific numerical example will be described. First, at point a in FIG. 2, the accelerator opening is 100%, and the engine speed is about 5000 rpm. In FIG. 2, the accelerator opening is 100%, and the engine speed is set to a speed near the minimum speed at which the maximum boost pressure is obtained and near the minimum speed at which knocking is free ( Set within the range of 2000 to 3000 rpm). The point C in FIG. 3 is the idle speed, the accelerator opening is about 80%, and the engine speed is around 650 rpm.

  Next, examples of output control of the engine 1 for switching the driving of the electric supercharger 5 and the motor 11 in accordance with the operating state of the engine 1 and the power storage control to the power storage device 15 as described above by the control unit 50 are shown in FIG. Will be described with reference to FIG.

  First, FIG. 3 shows the overall control. In step S10, various signals are input, and in step S11, the target torque To is calculated based on the accelerator opening α. At this time, the target torque To is generally calculated to be larger as the accelerator opening degree α is larger.

  Next, in step S12, whether or not it is a region where drive assist is performed, that is, referring to FIG. 2, the operating state of the engine 1 represented by the engine speed Ne and the target torque To is the supercharging region ( It is determined whether it is in the second area (Y) or the motor assist area (third area) Z. As a result, in the case of NO, that is, when in the non-supercharging region X, it is determined in step S13 whether or not the vehicle is decelerating. Whether or not the vehicle is decelerating can be determined, for example, when the accelerator opening is zero, or when the brake is operated in addition to the accelerator opening being zero.

  When the determination in step S13 is NO, in step S14, the power storage control is performed on the power storage device 15 as described later, and in step S15, the throttle opening TVO is calculated based on the target torque To. At this time, the throttle opening TVO is calculated to a value at which the engine output torque matches the target torque To. In step S16, the throttle valve 7 is driven and controlled so that the throttle opening TVO is obtained.

  On the other hand, if the determination in step S12 is YES, the process proceeds to step S17, and drive assist control described later is executed. Thereafter, in step S18, after the throttle opening is set to 100%, the process proceeds to step S16.

  If the determination in step S13 is YES, regenerative braking control is executed in step S19. This regenerative braking causes the motor generator 11 to function as a generator, applies a large resistance to the rotation of the engine 1 to promote deceleration, and stores power generated by the motor generator 11 in the power storage device 15. is there. The power storage control at the time of regenerative braking is performed so that the power storage amount becomes a large target power storage amount of, for example, 95% (can be a target power storage amount of 100% according to the degree of deterioration of the power storage device 15). . Of course, since it is during braking, fuel cut is performed. After step S19, the process proceeds to step S16.

  A detailed example of step S17 of FIG. 3 is shown in the flowchart of FIG. In FIG. 4, first, in step S21, the maximum engine torque Temax obtained in a non-supercharged state with only natural intake when the throttle opening is set to 100% is calculated based on the engine speed Ne. In calculating the maximum engine torque Temax at this time, for example, the torque characteristic of the engine 1 (corresponding to the boundary line defining the non-supercharging region X in FIG. 2) as illustrated in FIG. 5 is used.

  Next, in step S22, a supercharging torque Tb (torque for increasing the output of the engine 1 by driving the electric supercharger 5) is calculated by subtracting the maximum engine torque Temax from the target torque To.

  Next, in step S23, the maximum supercharging torque Tbmax within a range where surging of the electric supercharger 5 and knocking of the engine 1 does not occur is calculated based on the engine speed Ne. In calculating the maximum supercharging torque Tbmax at this time, for example, characteristics illustrated in FIG. 6 are used. That is, the maximum supercharging torque Tbmax is calculated to be a small value regardless of whether the engine speed Ne is smaller than a predetermined speed or larger than another predetermined speed. This is because, in the former case, as the engine speed Ne becomes smaller, problems such as surging of the electric supercharger 5 and knocking of the engine 1 are more likely to occur, and this is suppressed. In the latter case, as illustrated in FIG. 5, the maximum engine torque Temax increases as the engine speed Ne increases beyond the middle rotation range, and this is offset. That is, by adding the maximum supercharging torque Tbmax calculated in step S18 to the maximum engine torque Temax calculated in step S21, a boundary line that defines the upper limit torque of the supercharging region Y in FIG. 2 is obtained. .

  In this case, as indicated by a broken line in FIG. 6, the maximum supercharging torque Tbmax is calculated to be smaller as the charged amount SOC of the power storage device 15 is smaller than the predetermined charged amount. This is due to the following reasons.

  That is, referring to FIG. 7, when the storage amount SOC of the power storage device 15 that supplies power to the electric supercharger 5 and the motor 11 is sufficient, both the driving of the motor 11 and the driving of the electric supercharger 5 are sufficient. As a result, both the assist torque by the motor 11 and the maximum supercharging torque Tbmax by the electric supercharger 5 are sufficiently obtained, and as shown by the symbol a in FIG. At the time of transition between the (second region) Y and the motor assist region (third region) Z in which the motor 11 is driven, torque is smoothly connected, and uncomfortable torque shock or the like does not occur in the occupant.

  However, when the storage amount SOC of the power storage device 15 is smaller than the predetermined storage amount, the drive of the motor 11 becomes insufficient, and as shown by the chain line in the figure, the assist torque by the motor 11 decreases and the motor assist Since the total torque in the region Z becomes insufficient, the torque is not smoothly connected at the time of transition between the supercharging region Y and the motor assist region Z, and an unpleasant torque shock or the like occurs in the occupant.

  Therefore, when the storage amount SOC of the power storage device 15 is smaller than the predetermined storage amount, torque fluctuation (torque step difference) between the two regions Y and Z (in other words, when the motor 11 is switched between driving and non-driving). ), The maximum supercharging torque Tbmax by the electric supercharger 5 is set to a smaller value as the power storage amount SOC of the power storage device 15 is smaller than the predetermined power storage amount (shown by a broken line in FIG. The driving of the supercharger 5 is suppressed), so that the total torque in the supercharging region Y is reduced so that the torque is smoothly connected during the transition between the supercharging region Y and the motor assist region Z. . Thereby, the discomfort / discomfort of the passenger due to the torque shock is reduced.

  Here, it has been described that the torque step generated due to the decrease in the storage amount SOC of the power storage device 15 is caused by the decrease in the assist torque by the motor 11, but as described above, in the motor assist region Z, The torque increase by the electric supercharger 5 is relatively small and the torque support by the motor 11 is relatively large. As a result, the ratio of the torque of the motor 11 to the total torque is large (the torque of the motor 11). This is because the fluctuations of

  After step S23, in step S24, it is determined whether or not the supercharging torque Tb calculated in step S22 is less than the maximum supercharging torque Tbmax calculated in step S23. That is, it is determined whether or not the target torque To calculated in step S12 of FIG. 3 can be achieved only by driving the electric supercharger 5 within a range in which surging or knocking illustrated in FIG. 6 does not occur. .

  As a result, when YES, that is, when the target torque To is within the supercharging region Y, the routine proceeds to step S25, and the opening degree RVO of the relief valve 10 on the bypass passage 9 is set based on the supercharging torque Tb. calculate. At this time, as illustrated in FIG. 8, the relief valve opening degree RVO is calculated as a larger value as the supercharging torque Tb is larger. As a result, the flow rate of the gas circulating in the bypass passage 9 from the downstream side of the intercooler 6 to the upstream side of the compressor 3 increases, and the supercharging effect of the electric supercharger 5 is increased in order to achieve a large supercharging torque Tb. It will be fully demonstrated. Further, as exemplified in FIG. 8, the relief valve opening degree RVO is calculated to be larger as the engine speed Ne is smaller. This also increases the flow rate of the gas circulating in the bypass passage 9 from the downstream side of the intercooler 6 to the upstream side of the compressor 3, and the flow rate of the gas passing through the compressor 3 is reduced even if the engine speed Ne is small. Thus, the supercharging effect of the electric supercharger 5 is sufficiently exhibited.

  In step S26, the relief valve 10 is driven and controlled so that the relief valve opening RVO is obtained.

  Next, in step S27, the target intake pressure Pb immediately upstream of the throttle valve 7 in the intake passage 2 is calculated based on the supercharging torque Tb. However, in this case, since the high load is determined in step S13 and the throttle opening is 100% (fully open) (see step S18 in FIG. 3), the target intake pressure Pb is downstream of the throttle valve 7. For example, the pressure in the intake manifold 8 or surge tank (not shown) on the side may be used.

  At this time, the target intake pressure Pb is calculated as a larger value as the supercharging torque Tb is larger, as illustrated in FIG. Moreover, the change is made in two stages, and when the supercharging torque Tb is larger than the predetermined torque, the increase rate of the target intake pressure Pb is made larger than when it is small. This is because, as the supercharging torque Tb increases, the ignition timing is retarded (retarded) to prevent knocking, and the output of the engine 1 decreases accordingly, so that the target intake pressure Pb is increased to compensate for this. (Supercharged more).

  In step S28, the motor 4 of the electric supercharger 5 is driven so that the actual supercharging pressure becomes the target supercharging pressure Pb, and the rotational speed of the compressor 3 is feedback-controlled.

  On the other hand, if NO in step S24, that is, if the target torque To deviates from the supercharging region Y and is in the motor assist region Z, the process proceeds to step S29 before executing step S25 and subsequent steps. By subtracting the maximum supercharging torque Tbmax from the supply torque Tb, the motor torque Tm (torque for assisting the engine 1 by driving the motor 11) is calculated. That is, the target torque To calculated in step S11 of FIG. 3 cannot be achieved simply by driving the electric supercharger 5 within the range where surging or knocking illustrated in FIG. 6 does not occur. The minute is supplemented by torque assistance from the motor 11. In step S30, the motor 11 is driven and controlled so that the motor torque Tm is obtained.

  Next, in step S31, the value of the supercharging torque Tb is set to the value of the maximum supercharging torque Tbmax illustrated in FIG. 6, and then the control in step S25 and subsequent steps is executed.

  Details of step S14 (power storage control) in FIG. 3 are shown in FIG. First, in step S41, the distribution of power consumption of the power storage device 15 is approximated to a normal distribution, and its distribution characteristic value σ (for example, a variance value) is calculated. As illustrated in FIG. 11, the statistics are obtained by classifying the power consumption frequency (number of times) of the power storage device 15 generated within a predetermined time (for example, several minutes to several tens of minutes) in the past in the past. The width of the illustrated normal distribution curve is defined as a distribution characteristic value σ. In other words, the larger the distribution characteristic value σ, the more frequently the power consumption from the power storage device 15 is performed, which is more frequent in the electric turbocharger 5 and the motor generator 11 as the vehicle power source. It means that it was driven to.

  Next, in step S42, based on the distribution characteristic value σ, a first increase correction coefficient K1 for increasing the target power storage amount of the power storage device 15 is calculated. As illustrated in FIG. 12, the first increase correction coefficient K1 is set to a larger value (that is, the degree of increase correction is increased) as the distribution characteristic value σ is larger. However, when the distribution characteristic value σ is equal to or smaller than the predetermined value, the coefficient K1 is set to zero, and the increase correction is not performed.

  In step S42, the second increase correction coefficient K2 is calculated based on the engine speed Ne. As illustrated in FIG. 13, the second increase correction coefficient K2 is set to a larger value (that is, the degree of increase correction is increased) as the engine speed Ne is lower. However, when the engine speed Ne is equal to or greater than a predetermined value, the coefficient K2 is set to zero and no increase correction is performed.

  Next, in step S43, the degree of deterioration of the power storage device 15 is detected from the internal resistance change or the like of the power storage device 15, and then in step S44, based on the degree of deterioration of the power storage device 15, the third increase correction coefficient. K3 is calculated. As illustrated in FIG. 14, the third increase correction coefficient K3 is set to a larger value (that is, the degree of increase correction is increased) as the deterioration degree is larger. However, when the degree of deterioration is equal to or less than a predetermined value, the coefficient K3 is fixed to a predetermined minimum value (“1” in the embodiment) that is not zero.

  Next, in step S45, the first altitude change (height change) da1 is detected based on the information from the navigation system 30. The first altitude change da1 is a height change from 0 m above sea level, and da1 is set to a larger value as the mountain travels higher. The first altitude change da1 is for use as a parameter for detecting the intake air density described later.

  Next, in step S46, the second altitude change da2 is detected by looking at the atmospheric pressure change using the atmospheric pressure sensor 31. This second altitude change da2 is also used as a parameter for detecting the intake density, and for example, a change in atmospheric pressure from the atmospheric pressure in the standard state as a reference value is detected. Of course, if the outside air temperature is the same, the second altitude change da2 increases as the mountain travels higher.

  In step S47, the fourth increase correction coefficient K4 is set based on the added value of the two altitude changes da1 and da2. As illustrated in FIG. 15, the fourth increase correction coefficient K4 increases as the added value of da1 and da2 increases. However, when the added value is equal to or smaller than a predetermined value, a predetermined value other than 0 is set. Is set to the minimum value (“1” in the embodiment). As described above, the fourth increase correction coefficient K4 is set to a larger value as the altitude change is larger (as the altitude is higher and the intake density is smaller).

  The next step S48 is a step for obtaining a parameter for calculating the fifth increase correction coefficient K5 in step S49, that is, a driver's acceleration request level. For example, the following method is used to determine the accelerated melting degree. First, based on information from the navigation system 30 or the like, travel environment information ahead of the planned travel path of the vehicle is obtained. If the road ahead is a slope road (especially an ascending slope road) or an expressway entrance ramp, as shown in FIG. 16, the acceleration request is set to a maximum value of 1 (uphill or merging) This is because it is judged that the acceleration demand is high).

  On the other hand, if the road ahead is not a slope road (especially an uphill road) or an expressway entrance ramp, and the road ahead is in a traffic jam, it is determined that the acceleration request is low and the minimum value is Set to zero (because it is determined that the acceleration request is low due to deceleration or stopping).

  If none of the above is true (if the road ahead is not a ramp (especially climbing slope) or an expressway entrance ramp, and the road ahead is not busy), A value obtained by dividing the average acceleration by the maximum acceleration of the host vehicle is set as the acceleration request level. In this case, as the average acceleration of the vehicle in front of the planned travel path, the average acceleration (current value) of other vehicles that are currently traveling in front of the planned travel path may be adopted. You may employ | adopt the average acceleration (actual value of the own vehicle) when a vehicle drive | works ahead of the driving planned road which it is going to drive | work now.

  The fifth increase correction coefficient K5 based on the acceleration request degree determined in the above-described manner (acceleration request degree in the near future) is set to a larger value as the acceleration request degree increases (that is, the degree of increase correction is increased). ) However, even if the acceleration request degree is zero, the coefficient K5 is not set to zero.

  After step S49, in step S50, the target power storage amount is calculated by multiplying the base (basic) target power storage amount by “(1 + K1 × K2 × K3 × K4 × K5)”. In step S51, the power storage control for power storage device 15 is feedback-controlled so as to be the target power storage amount calculated in step S50.

  Here, when calculating (determining) the target charged amount in step S50, an upper limit value can be set so that the calculated target charged amount does not exceed a preset upper limit value. For example, by setting the upper limit value of the target power storage amount to 90%, for example (the base target power storage amount is 80%, for example), a margin for performing regenerative braking can always be ensured.

  As described above, when the intake air density is small, the frequency of operating the electric supercharger 5 increases to compensate for the decrease in the output of the engine 1, and the frequency of the motor generator 11 functioning as a motor is also high. However, when the intake air density is small, the amount of electricity stored in the power storage device 15 is increased compared to when the intake air density is high, so that the occurrence of a power shortage is prevented or reduced.

  Although the embodiment has been described above, the present invention is not limited to this, and includes the following cases, for example. Since the intake air density is largely governed by two parameters, the atmospheric pressure and the outside air temperature, the intake air density can be accurately known by detecting these two parameters. However, while there are many vehicles equipped with sensors that detect the outside air temperature, there are very few vehicles equipped with sensors that detect the atmospheric pressure, so instead of this atmospheric pressure, the altitude detected by the navigation system is used to know the intake air density. It is preferable to use it simply as a parameter. In short, it is possible to detect the intake air density using any one of the three parameters of altitude, outside air temperature, and atmospheric pressure, any two combinations, or all three, and other parameters. May be used to detect the intake air density (for example, the intake air density is indirectly detected from the relationship between the accelerator opening and the vehicle speed when traveling on a flat road in the non-supercharging region X). If the vehicle speed is the same, the accelerator opening increases as the intake air density decreases).

  The electric supercharger 5 is not limited to the case where the compressor 3 is driven only by a motor (electric motor), and the compressor 3 is compressed in an exhaust turbocharger connected to a turbine driven by exhaust energy. This includes the case where the machine is driven by a motor as appropriate (especially when the compressor is driven by the motor at low rotation and high load, and the motor is stopped in the high load range from medium to high rotation to exhaust energy. Etc. to drive the compressor). In other words, in the present invention, the non-supercharging state refers to a state where the motor 4 that drives the supercharging compressor 3 is not energized for driving.

  The setting of the drive region shown in FIG. 2 is merely an example, and the setting of the drive region of the electric supercharger 5 and the region in which the motor generator 11 functions as a motor can be changed as appropriate. As control by the control unit 50, shift control of an automatic transmission (which can be either a multi-stage transmission or a continuously variable transmission), change control of a shift characteristic, and the like can be performed together. For example, when the power storage amount of the power storage device 15 is small, control such as shifting the speed change characteristic to the low speed side (the gear ratio large side) can be performed together. Further, only immediately after the transition from the non-supercharging region X to the supercharging region Y, for example, the shift characteristic can be temporarily shifted to the low speed side for a predetermined time (for example, 1 second). Furthermore, although it is currently in the non-supercharging region X, when it is in the vicinity of the supercharging region Y, it is predicted that the supercharging region will be entered by an acceleration request, and the electric supercharger 5 is pre-rotated in advance, It is also possible to shift the speed change characteristic to the low speed side in advance. In particular, when the automatic transmission is a continuously variable transmission, it is possible to delicately perform a change ratio (shift for correction) width in a small range.

1 is a vehicle control system diagram for carrying out the present invention. A map showing the control area of the engine. The flowchart which shows the example of control of this invention. The flowchart which shows an example of the drive assist control shown by FIG. The characteristic view for demonstrating control of drive assist. The characteristic view for demonstrating control of drive assist. The characteristic view for demonstrating control of drive assist. The characteristic view for demonstrating control of drive assist. The characteristic view for demonstrating control of drive assist. Other than the above engine The flowchart which shows an example of the electrical storage control shown by FIG. The characteristic view for demonstrating electrical storage control. The characteristic view for demonstrating electrical storage control. The characteristic view for demonstrating electrical storage control. The characteristic view for demonstrating electrical storage control. . The characteristic view for demonstrating electrical storage control. The characteristic view for demonstrating electrical storage control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Engine 4: Motor 5: Electric supercharger 11: Motor generator 15: Power storage device 20: Accelerator opening sensor 21: Engine rotation sensor 30: Navigation system (for detecting altitude change related to intake air density)
31: Atmospheric pressure sensor (for detecting changes in air pressure related to intake air density)
40: Automatic transmission 50: Control unit

Claims (8)

A motor generator that is connected to an engine serving as a drive source for vehicle travel, and that selectively performs a function as a travel motor that assists the driving force of the engine and a function as a generator driven by the engine;
An electric supercharger for supercharging the intake air of the engine;
A power storage device that stores power generated by the motor generator and serves as a power supply source for the motor generator and the electric supercharger;
Load detection means for detecting parameters relating to engine load;
A rotational speed detecting means for detecting a parameter relating to the engine rotational speed;
An intake air density detecting means for detecting a parameter related to the intake air density;
Control means for controlling the motor generator and the electric supercharger based on the engine load detected by the load detection means and the engine rotation detected by the rotation speed detection means;
With
The control unit controls the power storage amount of the power storage device to be a target power storage amount, and when the intake air density detected by the intake air density detection unit is small, the target power storage amount is higher than when the intake air density is large. It is set to perform control to change the amount of stored electricity to a large value,
A control apparatus for a power train provided with an electric supercharger. In claim 1,
Winding road detection means for detecting that the traveling road surface is a winding road,
The control means is set to correct the target power storage amount to a larger value when a winding path is detected by the winding path detection means than when a winding path is not detected.
A control apparatus for a power train provided with an electric supercharger. Road type detection means for detecting whether the road is a motorway or a highway,
When the road type detection means detects that the road is an automobile-only road or an expressway, the control means sets the target storage amount to a larger value than when no automobile-only road or an expressway is detected. Set to correct,
A control apparatus for a power train provided with an electric supercharger. In any one of Claims 1 thru | or 3,
A control apparatus for a power train provided with an electric supercharger, wherein the intake air density detection means detects the intake air density based on at least one of atmospheric pressure and road altitude. In any one of Claims 1 thru | or 4,
A control apparatus for a power train comprising an electric supercharger, wherein the target charged amount is set in a range not exceeding an upper limit value set to a value smaller than 100% charged amount. In any one of Claims 1 thru | or 5,
The operating region is set in advance with the engine speed and the target torque set according to the accelerator opening as parameters,
The operation region is divided into three regions: a first region where the target torque is low or high, a second region where the target torque is high and medium, and a third region where the target torque is high and low. And
The control means prohibits drive assist by the motor generator and the electric supercharger in the first region, executes drive assist only by the electric supercharger in the second region, and in the third region. It is set to control to execute the drive assist of both the motor generator and the electric supercharger,
A control apparatus for a power train provided with an electric supercharger. In claim 6,
A first boundary characteristic line that is a boundary between the first region and the second region corresponds to a torque curve of an engine that is naturally aspirated without driving assist between the motor generator and the electric supercharger. Set to
The second boundary characteristic line that is the boundary between the second region and the third region is set so that the target torque increases rapidly as the engine speed increases.
A control apparatus for a power train provided with an electric supercharger. In claim 7,
The maximum rotational speed of the engine that has been naturally aspirated without driving assist of the motor generator and the electric supercharger is set to be close to the maximum rotational speed in the second region,
A control apparatus for a power train provided with an electric supercharger.

Images