supercharging system

Abstract

The present application provides a turbocharging system capable of achieving high-efficiency driving of an engine. The turbocharging system (10) is mounted on a vehicle, which has an engine, a driving operation portion to which a driving operation is input, and a power storage portion capable of charging and discharging. The turbocharging system has an exhaust turbine (13) to generate power by receiving exhaust gas of the engine, an intake compressor (14) to operate using power, a power converter (15) capable of supplying power from the power storage portion and recovering power to the power storage portion via a power path between the exhaust turbine and the intake compressor, and a control portion (16) to control the power converter. The control portion acquires a target value of compression power of the intake compressor based on an operation of the driving operation portion (6) and an operating state of the engine, and controls the power converter (15) to supply or recover power from or to the power storage portion corresponding to a difference between the acquired target value of the compression power and power generated by the exhaust turbine.

Description

Technical Field

[0001] This invention relates to a booster system for supplying compressed air to an engine. Background Technology

[0002] Previously, there have been mechanical turbochargers that use the rotational power of an exhaust turbine to drive an intake compressor and deliver compressed air from the intake compressor to the engine. Additionally, Patent Document 1 discloses a turbocharger that uses the rotational power of an exhaust turbine to generate electricity and uses the generated electricity to drive the intake compressor.

[0003] [Existing Technical Documents]

[0004] [Patent Documents]

[0005] Patent Document 1: Japanese Patent Application Publication No. 09-32569 Summary of the Invention

[0006] Technical issues

[0007] In the aforementioned conventional mechanical superchargers, the amount of compressed air delivered depends on the exhaust velocity, thus making it difficult to control the intake air volume. On the other hand, in the supercharger of Patent Document 1, the speed of the intake compressor is controlled electrically to supply intake air at a boost pressure corresponding to the fuel injection quantity in a stable mode with a constant accelerator opening. However, in the control of Patent Document 1, there is room for improvement in the intake air supply control in order to drive the engine efficiently under various operating conditions.

[0008] The purpose of this invention is to provide a supercharging system that can drive an engine with high efficiency under various operating conditions.

[0009] Technical solution

[0010] According to one aspect of the present invention, a supercharging system is mounted on a vehicle, the vehicle having an engine as an internal combustion engine, a driving control unit for inputting driving operations, and an electrical storage unit capable of charging and discharging; the supercharging system includes:

[0011] An exhaust turbine that generates electricity by receiving exhaust gas from the engine;

[0012] An electrically powered intake compressor supplies compressed intake air to the engine;

[0013] A power converter capable of supplying power to and recovering power from the power storage unit via a power path between the exhaust turbine and the intake compressor; and

[0014] The control unit controls the power converter.

[0015] The control unit obtains a target value of the compression power of the intake compressor based on the operation of the driving control unit and the operating state of the engine, and controls the power converter to supply or recover power from the power storage unit to the power storage unit, which corresponds to the difference between the obtained target value of the compression power and the power generated by the exhaust turbine.

[0016] Technical effect

[0017] According to the present invention, a target value for the compression power (e.g., power consumption) of the intake compressor corresponding to the operation of the driving control unit (e.g., the required torque corresponding to the driving operation) and the engine operating state (e.g., engine speed) is obtained. Furthermore, the power converter is controlled to output this compression power from the intake compressor. Therefore, it is possible to efficiently supply intake air to the engine under various operating conditions with different driving control unit operations and engine operating states. Moreover, according to the present invention, power is supplied to the intake compressor corresponding to the target value of compression power by supplying power from or recovering power from the power storage unit via the power path between the exhaust turbine and the intake compressor. Therefore, most of the power generated by the exhaust turbine is not transmitted to the intake compressor via the power storage unit, thus improving power efficiency and contributing to efficient engine operation. Attached Figure Description

[0018] Figure 1 This is a block diagram showing a vehicle equipped with a supercharging system according to an embodiment of the present invention.

[0019] Figure 2 This is a diagram showing an example of boost pressure mapping data (A) and compression power mapping data (B) stored in the control data storage unit.

[0020] Figure 3 This is a diagram showing an example of the first calibration table data (A) and the second calibration table data (B) stored in the control data storage unit.

[0021] Figure 4 This is a flowchart illustrating the pressurization control process executed by the control unit.

[0022] Figure 5 These are diagrams showing the first example (A), the second example (B), the exhaust turbine, the intake compressor, the electric converter, and the electrical lines between them.

[0023] Figure 6 These are figures showing modified examples 1(A) and 2(B) of the exhaust turbine and intake compressor.

[0024] Symbol Explanation

[0025] 1. Vehicle, 2. Drive wheels, 3. Engine, 4. Auxiliary equipment, 6. Driver's control unit, 10. Supercharging system, 11. Exhaust piping, 12. Intake piping, 13. Exhaust turbine, 13a. Rotating body, 13b. Generator, 14. Intake compressor, 14a. Rotating body, 14b. Electric motor, A1, A2. Rotating shafts, 15. Power converter, 16. Control unit, 17. Control data storage unit, H1. Pressure gauge, L1. Power line, L2. Branch line, MD1. Supercharger pressure mapping data, MD2. Compression power mapping data, TD1. First calibration table data, TD2. Second calibration table data Detailed Implementation

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a block diagram showing a vehicle equipped with a supercharging system according to an embodiment of the present invention. Figure 1 Vehicle 1 is an engine vehicle equipped with a supercharging system 10 according to an embodiment of the present invention. Vehicle 1 includes drive wheels 2, an engine 3 as an internal combustion engine, an auxiliary machine 4 (such as a fuel injection device) for operating the engine 3, a supercharging system 10 as an auxiliary machine for the intake and exhaust system, a driving control unit 6 operated by the driver, a driving control unit 20 that receives operating signals from the driving control unit 6 and controls the auxiliary machine 4 and the supercharging system 10, and an electrical storage unit 8 connected to the supercharging system 10 for charging and discharging. The driving control unit 6 includes an accelerator control unit, a brake control unit, and a steering unit.

[0027] The driving control unit 20 consists of a single ECU (Electronic Control Unit) or multiple ECUs operating in coordination. The driving control unit 20 receives operation signals from the driving operation unit 6 (primarily the accelerator opening signal from the accelerator operation unit) and controls the auxiliary engine 4 and the supercharging system 10, thereby driving the engine 3 in accordance with the driving operation. More specifically, based on the accelerator opening signal, the driving control unit 20 calculates the required torque corresponding to the driving operation and controls the auxiliary engine 4 and the supercharging system 10 to output the required torque from the engine 3. The required torque refers to the output torque required by the engine 3 based on the driving operation.

[0028] The supercharging system 10 includes an exhaust pipe 11 of the engine 3, an intake pipe 12 of the engine 3, an exhaust turbine 13 installed on the exhaust pipe 11, an intake compressor 14 installed on the intake pipe 12, an electrical line L1 installed between the exhaust turbine 13 and the intake compressor 14, an electrical converter 15 that supplies a portion of the power to the electrical storage unit 8 or recovers a portion of the power to the electrical storage unit 8 via the electrical line L1 and a branch line L2, a control unit 16 that controls the electrical converter 15, and a pressure gauge H1 that measures the boost pressure of the intake air. The pressure gauge H1 is located on the intake pipe 12 closer to the engine 3 than the throttle valve, and measures the intake air pressure at that location.

[0029] Exhaust pipe 11 supplies exhaust flow from engine 3, and exhaust turbine 13 is disposed therein. Exhaust pipe 11 may have a bypass pipe 11a that allows exhaust to flow around exhaust turbine 13 and a control valve 11b that controls the flow of exhaust to bypass pipe 11a. Switching control of control valve 11b may be performed by control unit 16.

[0030] The intake manifold 12 supplies intake air to the engine 3, and an intake compressor 14 is disposed therein. The intake manifold 12 may have a bypass manifold 12a that allows intake air to flow around the intake compressor 14, and a control valve 12b that controls the flow of intake air to the bypass manifold 12a. The switching control of the control valve 12b can be performed by the control unit 16.

[0031] The exhaust turbine 13 has a rotating body 13a that receives exhaust gas and rotates, and a generator 13b that generates electricity using the rotational motion of the rotating body 13a. The exhaust turbine 13 is an axial-flow turbine with the rotation axis of the rotating body 13a arranged along the flow of exhaust gas. By employing an axial-flow turbine, it is easy to arrange the input-side piping and output-side piping of the exhaust turbine 13 coaxially. Furthermore, by using an axial-flow structure as the exhaust turbine 13, which enables highly efficient operation at high exhaust flow velocities, high energy recovery efficiency can be achieved even when the engine 3 is a high-speed rotating type. The exhaust turbine 13 outputs the electricity generated by the generator to the power line L1.

[0032] The intake compressor 14 includes a rotating body 14a that compresses intake air and an electric motor 14b that drives the rotating body 14a to rotate. It is a centrifugal compressor that draws in intake air axially from the rotating body 14a and outputs the compressed air radially outward from the rotating body 14a. By employing a centrifugal compressor, it is easy to adopt a configuration where the piping on the input side of the intake compressor 14 crosses (e.g., orthogonally) with the piping on the output side. The intake compressor 14 is driven by receiving electricity from the power line L1.

[0033] One end of the power line L1 is connected to the generator 13b of the exhaust turbine 13, and the other end is connected to the electric motor 14b of the intake compressor 14. The power line L1 may include a relay or the like that is always connected during the operation of the boost system 10, or a rectifier element that prevents current from flowing back towards the generator 13b, between the exhaust turbine 13 and the intake compressor 14.

[0034] A power converter 15 is provided on a branch line L2 connected to the power line L1. The power converter 15 is located between the power line L1 and the power storage unit 8, and performs the functions of recovering power from the power line L1 to the power storage unit 8 and supplying power from the power storage unit 8 to the power line L1. The power converter 15 has a power semiconductor switch, and the flow of power is controlled by driving the power semiconductor switch.

[0035] The driving control unit 20 sends information indicating the operation of the driving operation unit 6 (e.g., torque request) and information indicating the operating status of the engine 3 (e.g., engine speed) to the control unit 16. Furthermore, the pressure gauge H1 sends boost pressure information to the control unit 16. The control unit 16 controls the power converter 15 based on this information. The control unit 16 consists of a single ECU or multiple ECUs operating in coordination. The control unit 16 may also be integrated with the driving control unit 20.

[0036] The control unit 16 further includes a control data storage unit 17 that stores control data for controlling the power converter 15. The control data storage unit 17 stores boost pressure mapping data MD1, compression power mapping data MD2, first calibration table data TD1, and second calibration table data TD2. Boost pressure mapping data MD1 corresponds to an example of the first mapping data of the present invention. Compression power mapping data MD2 corresponds to an example of the second mapping data of the present invention.

[0037] Figure 2 This is a diagram showing an example of boost pressure mapping data (A) and compression power mapping data MD2 (B) stored in the control data storage unit. Figure 3 This is a diagram showing an example of the first calibration table data (A) and the second calibration table data (B) stored in the control data storage unit.

[0038] The boost pressure mapping data MD1 represents the relationship between the engine 3's operating state (e.g., engine speed), quantities related to the operation of the driving control unit 6 (e.g., required torque), and the corresponding intake boost pressure. The compression power mapping data MD2 represents the relationship between the engine 3's operating state (e.g., engine speed), the intake boost pressure, and the compression power (e.g., operating electricity) of the intake compressor 14 required to output the boost pressure under that operating state.

[0039] The first calibration table data TD1 represents the relationship between a specific operation of the driving control unit 6 (e.g., a sharp accelerator operation) and the corresponding calibration value of the compression power. A sharp accelerator operation refers to an accelerator operation in which the rate of increase of the accelerator operation amount per predetermined time reaches or exceeds a preset threshold, and multiple levels of specific operation are set according to the rate of increase. The second calibration table data TD2 represents the calibration value used to reduce the error between the target boost pressure and the actual boost pressure. The calibration values ​​of the compression power (operating power) are shown in the first calibration table data TD1 and the second calibration table data TD2.

[0040] <Action Instructions>

[0041] Figure 4 This is a flowchart illustrating the boost control process executed by the control unit. The control unit 16, driven by the engine 3, repeatedly executes this process according to predetermined control cycles. Figure 4 The boost control process. When a control cycle begins, firstly, the control unit 16 obtains the target value of the intake boost pressure corresponding to the above-mentioned operation and operating state (hereinafter referred to as "target boost pressure") based on the information related to the operation of the driving operation unit 6 (required torque) and the operating state (speed) of the engine 3, referring to the boost pressure mapping data MD1 (step S1).

[0042] Next, the control unit 16 refers to the compression power mapping data MD2 to obtain the compression power (e.g., the operating power of the intake compressor 14) required to output the target boost pressure in the operating state of the engine 3 during the current control cycle (step S2). The value of the compression power obtained in step S2 is equivalent to the target value of the compression power that should be output from the intake compressor 14 under the control of the control unit 16.

[0043] Next, the control unit 16 determines whether a specific operation requiring rapid acceleration (sharp accelerator operation) has been performed (step S3). If the specific operation has been performed, the driving control unit 20 notifies the control unit 16. Then, if the determination result of step S3 is "yes", the control unit 16 calculates the correction amount of the compression power (operating power of the intake compressor 14) corresponding to the amount of the specific operation with reference to the first correction table data TD1, and applies the correction amount to the compression power (step S4).

[0044] Next, the control unit 16 compares the target boost pressure from the control cycle n times ago (one or more times ago) with the boost pressure measured by the pressure gauge H1 at the moment when the intake air is output according to the control of that control cycle, and calculates the boost pressure error (step S5). Then, the control unit 16 determines whether the boost pressure error exceeds a threshold (e.g., ±5%) (step S6). If the determination result is "yes", the control unit 16 calculates the correction amount of the compression power (operating power of the intake compressor 14) corresponding to the error with reference to the second correction table data TD2, and applies the correction amount to the compression power (step S7).

[0045] Next, the control unit 16 controls the power converter 15 to operate the intake compressor 14 with the final compression power obtained from the intake compressor 14 (step S8). Through this control, the difference between the operating power of the intake compressor 14 and the generated power of the exhaust turbine 13 is supplied from or recovered from the power storage unit 8 via the power converter 15. Through the control in step S8, power corresponding to the compression power is supplied to the intake compressor 14, and the compression power is output from the intake compressor 14. Then, one boost control process ends. When the next control cycle begins, the control unit 16 again executes the boost control process starting from step S1.

[0046] <Specific examples of the electrical configuration of a booster system>

[0047] Figure 5 These are diagrams illustrating, in detail, the exhaust turbine, the intake compressor, the electric converter, and the electrical lines connecting them, as shown in the first example (A) and the second example (B). It should be noted that... Figure 5 The diagram shows an example where the exhaust turbine 13 is a centrifugal turbine, but the exhaust turbine 13 can also be an axial flow turbine. Additionally, the intake compressor 14 can also be an axial flow turbine.

[0048] Figure 5 The first example shown in (A) is an example that uses a DC generator that generates DC power as the generator 13b of the exhaust turbine 13, and a DC motor that receives DC power and drives it as the electric motor 14b of the intake compressor 14. In this configuration, a DC two-wire power line with an anode wire P and a cathode wire N can be used as the power line L1 and the branch line L2. Moreover, the power converter 15 can be a DC / DC converter that converts the DC voltage of the power storage unit 8 into the DC voltage of the power line L1. In addition, a battery (lithium-ion secondary battery, lead battery, etc.) or a capacitor (electric double layer capacitor, etc.) can be used as the power storage unit 8, but... Figure 5 The example in (A) uses a battery.

[0049] In the configuration of the first example, the control unit 16 controls the output voltage (voltage of the power line L1) of the power converter 15 to a value corresponding to the compression power of the intake compressor 14, which is the target. It can appropriately supply power from the power storage unit 8 or recover power from the power storage unit 8 according to the power generated by the exhaust turbine 13, so as to drive the intake compressor 14 with the target compression power (e.g., operating power).

[0050] In detail, in the first example configuration, with the engine speed of 3 set to a constant, increasing the voltage of the power line L1 increases the speed of the intake compressor 14, and increases the operating power and compression force of the intake compressor 14. Therefore, the intake boost pressure increases. Conversely, decreasing the voltage of the power line L1 decreases the speed of the intake compressor 14, and decreases the operating power and compression force of the intake compressor 14. Therefore, the intake boost pressure decreases. Here, if the exhaust turbine 13 has a low speed and the generated power from the exhaust turbine 13 is small, the effect of increasing the voltage of the power line L1 by supplying generated power is reduced, and correspondingly, the power supplied from the power storage unit 8 to the power line L1 increases by controlling the output voltage of the power converter 15. On the other hand, if the exhaust turbine 13 has a high speed and the generated power from the exhaust turbine 13 is large, the effect of increasing the voltage of the power line L1 by supplying generated power increases, and correspondingly, the power supplied from the power storage unit 8 to the power line L1 decreases by controlling the output voltage of the power converter 15. Alternatively, when the power generated by the exhaust turbine 13 is greater, power can be recovered from the power line L1 to the power storage unit 8 by controlling the output voltage of the power converter 15. Through this action, the difference between the power generated by the exhaust turbine 13 and the compression power (operating power) of the intake compressor 14 can be supplied to or recovered from the power storage unit 8, enabling the intake compressor 14 to be driven with the target compression power.

[0051] Figure 5 The second example shown in (B) is an example that uses a three-phase alternator as the generator 13b of the exhaust turbine 13 and a three-phase alternating current motor as the motor 14b of the intake compressor 14. In this configuration, a three-phase three-wire power line can be used as the power line L1 and the branch line L2. Moreover, as the power converter 15, an inverter that can convert the DC voltage of the power storage unit 8 into a three-phase alternating current voltage can be used. In addition, as the power storage unit 8, a battery (lithium-ion secondary battery, lead-acid battery, etc.) or a capacitor (double-layer capacitor, etc.) can be used, but... Figure 5 In example (B), a capacitor was used.

[0052] In the second configuration, the control unit 16 controls the output voltage of the power converter 15 (the three-phase AC voltage output to the power line L1) to an AC voltage corresponding to the target value of the compression power. It can then appropriately supply power from the power storage unit 8 or recover power from the power storage unit 8 based on the power generated by the exhaust turbine 13, thereby driving the intake compressor 14 with the target compression power (e.g., operating power).

[0053] In detail, in the second configuration, the power converter 15 outputs an AC voltage that drives the intake compressor 14 to a predetermined torque and a predetermined speed, thereby driving the intake compressor 14 with a compression power (e.g., operating power) corresponding to the predetermined torque and predetermined speed. Therefore, a boost pressure corresponding to this compression power can be obtained. At this time, the electricity generated by the exhaust turbine 13 is supplied to the power line L1, but by controlling the AC voltage of the power converter 15, the power converter 15 operates in such a way that the difference between the electricity generated by the exhaust turbine 13 and the operating power of the intake compressor 14 is supplied from or recovered from the power storage unit 8.

[0054] It should be noted that when the generator 13b of the exhaust turbine 13 is a three-phase AC generator and the electric motor 14b of the intake compressor 14 is a three-phase AC electric motor, the following configuration can also be applied. That is, the configuration is as follows: the power line L1 and branch line L2 are DC two-wire type; the intake compressor 14 is connected to the power line L1 via a first inverter; the exhaust turbine 13 is connected to the power line L1 via a second inverter; and the branch line L2 is connected to the power storage unit 8. In this configuration, the control unit 16 controls the first inverter to drive the intake compressor 14 with a target compression power (e.g., operating power), and controls the second inverter to achieve efficient power recovery based on the rotational speed of the exhaust turbine 13. Even with this configuration, it is possible to supply or recover power from the power storage unit 8 via the first and second inverters, based on the difference between the generated power of the exhaust turbine 13 and the compression power (operating power) of the intake compressor 14. A rectifier element, such as a power diode, that is configured not to supply power to the exhaust turbine 13 can also be installed between the first inverter and the second inverter.

[0055] exist Figure 5 (A) and Figure 5In configuration (B), the control unit 16 does not measure the generated electricity of the exhaust turbine 13, but supplies insufficient electricity from the power storage unit 8 via the power converter 15 or recovers excess electricity to the power storage unit 8 to drive the intake compressor 14 with the target compression power. However, the booster system 10 may also have a measuring device that measures quantities related to the generated electricity of the exhaust turbine 13 (such as the rotational speed of the rotating body), and the control unit 16 uses the value of the measuring device to identify the generated electricity and calculate the excess or deficiency of electricity, thereby controlling the power converter 15 to supply the insufficient electricity or recover the excess electricity.

[0056] <Examples of variations of intake compressors and exhaust turbines>

[0057] Figure 6 These figures illustrate modified examples 1(A) and 2(B) of the intake compressor and exhaust turbine. In this embodiment, the booster system 10 temporarily converts the kinetic energy recovered by the exhaust turbine 13 into electrical energy and supplies it to the intake compressor 14. Therefore, compared to a mechanical booster that directly supplies kinetic energy from the exhaust turbine to the intake compressor, the configuration of the exhaust turbine 13 and the intake compressor 14 offers greater freedom. Because of this freedom, the booster system 10 can be configured as in modified examples 1 and 2.

[0058] like Figure 6 As shown in (A), Modification 1 is an example of a configuration in which the exhaust turbine 13 and the intake compressor 14 are centrifugal, and the rotation axis A1 of the rotating body of the exhaust turbine 13 and the rotation axis A2 of the rotating body of the intake compressor 14 are not arranged on the same axis.

[0059] like Figure 6 As shown in (B), Modification 2 is an example in which the exhaust pipe 11 is separated from the intake pipe 12, and the exhaust turbine 13 is separated from the intake compressor 14.

[0060] The form and configuration of the exhaust turbine 13 and the intake compressor 14 are not limited to Figure 1 , Figure 6 (A) and Figure 6 In example (B), various modifications are possible. For instance, the rotation axis A1 of the rotating body of the exhaust turbine 13 and the rotation axis A2 of the rotating body of the intake compressor 14 can be coaxial, and the intake compressor 14 can also be an axial flow type. Furthermore, the exhaust turbine 13 and the intake compressor 14 can be configured in any orientation in conjunction with the exhaust pipe 11 and the intake pipe 12.

[0061] When using an axial-flow exhaust turbine or an axial-flow intake compressor, high efficiency is achieved at high exhaust or intake air velocities, thus enabling a highly efficient turbocharging system for high-speed engines. Conversely, when using a centrifugal exhaust turbine or a centrifugal intake compressor, high efficiency is achieved at low exhaust or intake air velocities, enabling a highly efficient turbocharging system for low-speed engines. Therefore, by selecting the type of exhaust turbine and intake compressor, turbocharging efficiency can be improved to suit various engine characteristics.

[0062] The configuration of the exhaust turbine 13 and the intake compressor 14 can be flexibly set in accordance with the configuration space of the components during the design of the vehicle 1, so that even if the configuration space is limited, it is easy to install the supercharging system.

[0063] As described above, the supercharging system 10 according to this embodiment includes an exhaust turbine 13 that receives exhaust gas from the engine 3 and generates electricity, an intake compressor 14 that operates using electricity, and a power converter 15 that can supply electricity to or recover electricity from the power storage unit 8 via an electrical path (electric line L1) between the exhaust turbine 13 and the intake compressor 14. Furthermore, the control unit 16 determines a target value for the required compression power (e.g., operating power) of the intake compressor 14 based on the operation of the driving operation unit 6 and the operating state of the engine 3, and controls the power converter 15 to supply or recover electricity from the power storage unit 8 corresponding to the difference between the determined target value of compression power and the generated electricity of the exhaust turbine 13. Through such control, for example, from requiring various output torques at low engine speeds to requiring various output torques at high engine speeds, intake air can be delivered to the engine 3 at a boost pressure corresponding to various operating conditions. Therefore, high-efficiency driving of the engine 3 can be achieved under various operating conditions. Furthermore, the power converter 15 supplies power to the power line L1 between the exhaust turbine 13 and the intake compressor 14, or recovers power from the power line L1, so most of the power generated by the exhaust turbine 13 is not transmitted to the intake compressor 14 via the power storage unit 8. Therefore, the power efficiency is improved, which contributes to the high-efficiency driving of the engine 3.

[0064] Furthermore, according to the supercharging system 10 of this embodiment, the control unit 16 includes supercharging pressure mapping data MD1, which represents the operating state of the engine 3 (e.g., engine speed), the amount of operation of the driving control unit 6 (e.g., required torque), and the relationship between the supercharging pressure of the intake air corresponding to them. Furthermore, the control unit 16 includes compression power mapping data MD2, which represents the relationship between the operating state of the engine 3 (e.g., engine speed), the supercharging pressure, and the compression power (e.g., operating electricity) of the intake compressor 14 used to generate the supercharging pressure in that operating state. The control unit 16 uses the supercharging pressure mapping data MD1 and the compression power mapping data MD2 to determine the compression power (e.g., operating electricity) of the intake compressor 14 as the target. Therefore, the control unit 16 can appropriately determine the supercharging pressure corresponding to the operating state of the engine 3 and the operation of the driving control unit 6 with a relatively small load.

[0065] Furthermore, according to the boosting system 10 of this embodiment, a pressure gauge H1 is provided to measure the boost pressure of the intake air. When there is a difference between the target boost pressure obtained using the boost pressure mapping data MD1 and the measured value of the pressure gauge H1, the control unit 16 corrects the target value of the compression power obtained using the compression power mapping data MD2. Through such correction processing, the accuracy of the boost pressure of the intake air actually supplied from the intake compressor 14 can be further improved. Furthermore, since the control unit 16 temporarily obtains the target boost pressure based on the boost pressure mapping data MD1, it is easy to perform the processing of calculating the difference between the actual boost pressure and the target boost pressure.

[0066] Furthermore, according to the supercharging system 10 of this embodiment, when a specific operation (rapid accelerator operation) is performed via the driving operation unit 6, the control unit 16 corrects the target value of the compression power (e.g., operating power) of the intake compressor 14 based on the time-varying rate of change of the accelerator operation amount. In the presence of a specific operation by the driving operation unit 6, temporarily correcting the intake boost pressure can sometimes improve the driving efficiency of the engine 3. Therefore, through the correction process described above, it is possible to control the boost pressure corresponding to the specific operation of the driving operation unit 6, thereby further improving the driving efficiency of the engine 3.

[0067] Furthermore, according to the pressurization system 10 of this embodiment, such as Figure 5As shown in (A), a configuration can be applied where the exhaust turbine 13 has a DC generator, the intake compressor 14 has a DC motor, and the power converter 15 is a DC / DC converter. With this configuration, most of the electricity generated by the exhaust turbine 13 can be supplied to the intake compressor 14 without passing through the power storage unit 8, and only the insufficient amount of electricity or only the excess amount of electricity can be supplied via the power converter 15. Therefore, the energy of the exhaust gas from the engine 3 can be used efficiently as energy to generate boost pressure, which correspondingly contributes to the efficient operation of the engine 3.

[0068] The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above. For example, in the above embodiments, the engine speed of engine 3 is shown as an example of using parameters representing the engine's operating state according to the present invention. However, the engine's operating state can also be represented by other parameters such as fuel injection quantity, ignition timing, and load. In addition, in the above embodiments, the required torque is shown as an example of using quantities representing the operation of the driving control unit according to the present invention. However, other quantities such as required power (the required value of the engine's output power) or the operation quantity of the accelerator control unit can also be used as quantities representing the operation of the driving control unit. Furthermore, in the above embodiments, the target value of the compression power is shown as an example of using the target value of the operating power of the intake compressor 14. However, for example, when the compression power is determined by the input voltage input to the electric motor of the intake compressor 14, the target value of the compression power can also be the target value of the input voltage, and the specific value can be varied. In addition, the details shown in the embodiments can be appropriately modified without departing from the spirit of the invention.

Claims

1. A booster system, characterized in that, Mounted in a vehicle, the vehicle having an engine as an internal combustion engine, a driving control unit for inputting driving operations, and an electrical storage unit capable of charging and discharging, the supercharging system having: An exhaust turbine that generates electricity by receiving exhaust gas from the engine; An electrically powered intake compressor supplies compressed intake air to the engine; A power converter capable of supplying power to and recovering power from the power storage unit via a power path between the exhaust turbine and the intake compressor; and The control unit controls the power converter. The control unit acquires a target value for the compression power of the intake compressor based on the operation of the driving control unit and the operating state of the engine, and controls the power converter to supply or recover power from the power storage unit corresponding to the difference between the acquired target value of the compression power and the power generated by the exhaust turbine. The driving control unit includes an accelerator control unit. If the increase rate of the operation amount of the accelerator operation unit exceeds a threshold, the control unit will correct the target value of the compression force to a large value.

2. The booster system according to claim 1, characterized in that, The control unit includes: The first mapping data represents the relationship between the operation, the operating state, and the boost pressure of the intake air corresponding to the operation and the operating state. as well as The second mapping data represents the relationship between the operating state, the boost pressure, and the compression force used to generate the boost pressure in the operating state. The control unit uses the first mapping data and the second mapping data to obtain the target value of the compression force.

3. The booster system according to claim 2, characterized in that, The boosting system includes a measuring device for measuring the boost pressure of the intake air. If there is a difference between the boost pressure of the intake air obtained from the first mapping data and the boost pressure measured by the measuring instrument, the control unit corrects the target value of the compression power based on the difference.

4. The booster system according to any one of claims 1 to 3, characterized in that, The exhaust turbine has a DC generator, the intake compressor has a DC motor that outputs compression power, and the power converter is a DC / DC converter.

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