JP2004270602A - Supercharging device and method of supercharging engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method of supercharging that can use energy recovered from an engine effectively and that can improve responsiveness to an acceleration request. <P>SOLUTION: This supercharging device 20 is applied to an engine 1 including a regenerative generator 30 and a rechargeable battery 31 using regenerative power that is recovered by the generator 30, and rotates and drives a compressor impeller 22 by a turbine impeller 21 turned by exhaust from the engine 1 and compresses intake air by the impeller 21, including a turbo generator 24 capable of rotating and driving the impeller 22. The turbo generator 24 is driven by regenerative power that is recovered by the generator 30 when the battery 31 is in full charge. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a supercharging device and a method for supercharging an engine.
[0002]
[Prior art]
2. Description of the Related Art As a supercharging device for an engine, a so-called motor-assisted turbocharger having an electric motor capable of driving a compressor impeller for compressing intake air has been known (for example, see Patent Document 1). In this conventional supercharging device, the electric motor is driven by using the electric power stored in the battery when the engine is rotating at a low speed or the like. Thereby, the supercharging pressure by the compressor impeller is increased, so that the engine torque can be increased. Further, in this supercharging device, at the time of braking, the electric motor is driven in a direction opposite to the case where the supercharging pressure is increased. As a result, the pressure in the exhaust manifold of the engine increases, so that the pumping loss of the piston can be increased and the braking force can be increased.
[0003]
[Patent Document 1]
JP-A-5-141254
[Problems to be solved by the invention]
However, the above-described conventional supercharger basically operates the electric motor from the stage at which an acceleration request is made, and there is still room for improvement in the response to the acceleration request. If the response to the acceleration request is not satisfactory, large electric power must be supplied to the electric motor of the supercharger when the acceleration request is made to compensate for the responsiveness. In addition, when the supercharging device is reversely operated at the time of braking as in the above-described conventional example, there is essentially no waste of energy recovered from the engine. Therefore, the conventional supercharging device has a problem in terms of energy efficiency.
[0005]
Therefore, an object of the present invention is to provide a supercharging device and a supercharging method for an engine that can effectively use energy recovered from an engine and improve responsiveness to an acceleration request.
[0006]
[Means for Solving the Problems]
The supercharging device according to the present invention is applied to an engine including a regenerative generator and a battery that can be charged using regenerative power recovered by the regenerative generator, and is compressed by a turbine element that is rotated by exhaust gas of the engine. A supercharger that rotationally drives a compressor element and compresses intake air by the compressor element, wherein the electric motor is connected to the compressor element and is capable of rotationally driving the compressor element, and a battery is in a fully charged state. Control means for driving the electric motor by the regenerative electric power collected by the regenerative generator.
[0007]
In this supercharging device, when the battery that can be charged using the regenerative power recovered by the regenerative generator is in a fully charged state, the regenerative power recovered by the regenerative generator is connected to the electric motor connected to the compressor element. Used to drive the Thereby, in this supercharging device, when the regenerative generator is operating, such as when the engine is decelerated, and the battery is in a fully charged state, the regenerative power recovered by the regenerative generator is effectively used. Thus, the pressure of the intake air of the engine can be increased. As a result, according to the present invention, it is possible to greatly improve the responsiveness of the supercharging device when an acceleration request is made to the engine.
[0008]
Further, when the regenerative power recovered by the regenerative generator exceeds the surplus power until the battery is fully charged, it is preferable that the motor be driven by the regenerative power regardless of the state of charge of the battery. .
[0009]
By employing such a configuration, it is possible to increase the pressure of the intake air of the engine by effectively using surplus regenerative power that cannot be used for charging the battery.
[0010]
Further, the control means monitors the acceleration / deceleration frequency of the engine, and when the acceleration / deceleration frequency exceeds a predetermined frequency, the motor is driven by the regenerative power regardless of the state of charge of the battery. It is preferable.
[0011]
By adopting such a configuration, when the engine is to be decelerated and the possibility of re-acceleration is high thereafter, the electric motor can be operated in advance to increase the pressure of the intake air. The responsiveness to the acceleration request of the supercharging device can be improved extremely favorably.
[0012]
The supercharging method for an engine according to the present invention is applied to an engine including a regenerative generator and a battery that can be charged using regenerative power recovered by the regenerative generator, and rotates a turbine element by exhaust of the engine. In a method for supercharging an engine, in which a compressor element is driven to rotate and a compressor element compresses intake air, an electric motor is connected to the compressor element so that when a battery is fully charged, a regenerative generator The electric motor is driven using the regenerative electric power collected by the electric motor.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a supercharging device and a supercharging method for an engine according to the present invention will be described in detail with reference to the drawings.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic configuration diagram showing an engine to which a supercharging device according to the present invention is applied. The engine 1 shown in FIG. 1 is configured as an in-cylinder injection type multi-cylinder engine for a vehicle (for example, a four-cylinder engine, but only one cylinder is shown in FIG. 1). The piston 3 is reciprocated by the combustion of the air-fuel mixture in the above, and power is obtained from the crankshaft S. Here, the engine 1 is described as a so-called in-cylinder injection type (gasoline) engine, but is not limited thereto, and the present invention can be applied to an intake pipe injection type engine, a diesel engine, and the like. Needless to say.
[0015]
As shown in FIG. 1, the piston 3 of the engine 1 is configured as a so-called deep dish top surface type, and has a concave portion on its upper surface. In addition, a plurality of injectors 4 are arranged in the cylinder head of the engine 1 so as to face each combustion chamber 2. The injector 4 is connected to a fuel tank (both not shown) for storing liquid fuel such as gasoline via a fuel supply pipe, and directly injects fuel such as gasoline into the corresponding combustion chamber 2. Further, a plurality of spark plugs 5 are arranged in the cylinder head of the engine 1 so as to face each combustion chamber 2.
[0016]
In the engine 1 configured as described above, fuel such as gasoline is directly injected from the injector 4 toward the recess of each piston 3 in a state where a large amount of air is sucked into each combustion chamber 2. Thus, a layer of a mixture of fuel and air is formed (stratified) in the vicinity of the ignition plug 5 in a state separated from the surrounding air layer. As a result, in the engine 1, it is possible to execute a stable lean burn operation using an extremely lean air-fuel mixture.
[0017]
An intake port of each combustion chamber 2 is connected to an intake manifold (intake path) 6, and an exhaust port of each combustion chamber 2 is connected to an exhaust manifold (exhaust path) 7. An intake valve Vi for opening and closing an intake port and an exhaust valve Ve for opening and closing an exhaust port are provided for each cylinder in a cylinder head of the engine 1. Each intake valve Vi and each exhaust valve Ve are opened and closed by a valve operating mechanism 8 having a variable valve timing function.
[0018]
The intake manifold 6 is connected to a surge tank 9 as shown in FIG. 1, and the surge tank 9 is connected to an air cleaner 11 via an air supply pipe 10. Dirt, dust and the like in the intake air are removed by the air cleaner 11. A throttle valve 12 for adjusting the amount of intake air is provided in the middle of the air supply pipe 10. In the present embodiment, the throttle valve 12 includes an accelerator position sensor 13 for detecting an operation amount (depressed amount) of an accelerator pedal AP, a throttle motor 14 for opening and closing the throttle valve 12, and a throttle for detecting an opening degree of the throttle valve 12. A so-called electronically controlled throttle including the opening degree sensor 15 is employed. Further, a pressure sensor 16 for detecting the pressure (intake pressure) in the air supply pipe 10 is arranged between the surge tank 9 and the throttle valve 12 in the air supply pipe 10.
[0019]
On the other hand, as shown in FIG. 1, the exhaust manifold 7 is connected to a catalyst device 17 including, for example, a NOx storage reduction catalyst. In the catalyst device 17, the exhaust gas from each combustion chamber 2 is purified. Further, the engine 1 of the present embodiment has an EGR (Exhaust Gas Recirculation) flow path 18 for recirculating exhaust gas from the exhaust manifold 7 to the surge tank 9 of the intake system. An EGR valve 19 for adjusting the amount of exhaust gas recirculated is provided in the middle of the EGR passage 18.
[0020]
Now, the in-cylinder injection type engine 1 as described above performs a lean burn operation by introducing a large amount of intake air into each combustion chamber 2 to achieve both high output and low fuel consumption. And a supercharging device (turbocharger) 20. As shown in FIG. 1, the supercharging device 20 includes a turbine impeller (turbine element) 21 and a compressor impeller (compressor element) 22. The turbine impeller 21 and the compressor impeller 22 are connected to each other by a rotating shaft 23 to be integrated.
[0021]
As shown in FIG. 1, the turbine impeller 21 is rotatably disposed inside a casing incorporated between the exhaust manifold 7 and the catalyst device 17. Further, the compressor impeller 22 is rotatably disposed inside a casing incorporated between the air cleaner 11 of the air supply pipe 10 and the throttle valve 12. Thus, the compressor impeller 22 can be driven to rotate by the turbine impeller 21 rotated by the exhaust gas from each combustion chamber 2, and the compressor impeller 22 compresses the air sucked in through the air cleaner 11. (Supercharging).
[0022]
The supercharging device 20 of the present embodiment is configured as a so-called motor-assisted turbocharger, and has a turbo motor 24 mounted on a rotating shaft 23 that connects a turbine impeller 21 and a compressor impeller 22. That is, the supercharging device 20 can not only function as a normal turbocharger that compresses intake air using only the energy of the exhaust gas of the engine 1, but also operates the turbo motor 24 to forcibly force the compressor impeller 22. By rotationally driving, the pressure of the intake air (supercharging pressure) can be further increased. As the turbo motor 24, an AC motor including a rotor fixed to the rotating shaft 23 and a stator arranged around the rotor is employed. As shown in FIG. Connected. Note that a so-called motor / generator that can function as both a motor and a generator may be employed as the turbo motor 24. This makes it possible to recover electric energy by operating the turbo motor 24 as a generator using the energy of the exhaust gas.
[0023]
Further, the supercharging device 20 includes an intercooler 26 incorporated in the air supply pipe 10 so as to be located between the compressor impeller 22 and the throttle valve 12. The intercooler 26 improves the charging efficiency by cooling the intake air that has been heated by being compressed by the compressor impeller 22. As the intercooler 26, an air-cooled or liquid-cooled heat exchanger is employed. Further, the air supply pipe 10 is provided with a bypass passage 27 that bypasses the upstream side and the downstream side of the supercharging device 20 (compressor impeller 22). The bypass passage 27 is opened and closed by an air bypass valve 28 provided on the way. As the air bypass valve 28, a valve that can be electrically controlled to open and close is preferably used, and a mechanical type valve that opens when the pressure on the downstream side of the compressor impeller 22 becomes higher than the pressure on the upstream side by a predetermined value. A directional valve may be used.
[0024]
The supercharging device 20 of the present embodiment is configured as a so-called variable nozzle turbo, and has a plurality of movable vanes disposed outside the turbine impeller 21. That is, by controlling the flow rate of the exhaust gas flowing into the turbine impeller 21 by changing the positions of the movable vanes, the supercharging pressure can be freely adjusted. Further, the supercharging device 20 may include a mechanism for variably controlling the turbine capacity (A / R variable mechanism) and the like. Further, although not shown, a flow path that bypasses the supercharging device 20 is provided for the exhaust manifold 7, and a waste gate valve is provided in the middle of this flow path. The waste gate valve opens when the supercharging pressure becomes equal to or higher than a predetermined pressure, and adjusts the supercharging pressure by reducing the flow rate of exhaust gas to the turbine impeller 21.
[0025]
Further, in addition to the above-described supercharger 20, the engine 1 has a regenerative generator 30 connected to the crankshaft S as shown in FIG. The regenerative generator 30 can function as a regenerative brake unit that cooperates with a hydraulic brake unit (not shown), and is connected via an inverter unit 25 to a battery 31 used as a power source for various auxiliary machines. That is, when the accelerator pedal AP is returned or a command to decelerate or stop the engine 1 (vehicle) is issued, the regenerative generator 30 converts and recovers the kinetic energy of the engine 1 into electric energy. Thus, a braking force is applied to the engine 1. Then, the regenerative electric power regenerated by the regenerative generator 30 is converted into a voltage by the inverter unit 25 and used for charging the battery 31.
[0026]
The braking force by the regenerative generator 30 (regenerative brake) and the braking force by the hydraulic brake unit are appropriately combined so that energy recovery is most efficiently performed. Further, as the regenerative generator 30, a so-called motor / generator that can function as both an electric motor and a generator may be employed, and a vehicle including the above-described engine 1 and the supercharging device 20 may be configured as a so-called hybrid vehicle. .
[0027]
Further, the above-described engine 1 includes an ECU 40 functioning as control means. The ECU 40 includes a CPU, a ROM, a RAM, an input / output port, a storage device, and the like, all of which are not shown. The input / output ports of the ECU 40 include the injector 4, the spark plug 5, the valve operating mechanism 8, the accelerator position sensor 13, the throttle opening sensor 15, the throttle motor 14, the pressure sensor 16, the EGR valve 19, and the inverter unit 25. , An air bypass valve 28, a crank angle sensor 29, and the like. The ECU 40 controls the injector 4, the spark plug 5, the valve train 8, the throttle valve 12, and the like based on detection values of various sensors, using various maps and the like stored in the storage device. The ECU 40 also functions as control means for the supercharging device 20 (turbo electric motor 24) during braking of the engine 1.
[0028]
Next, the operation of the supercharging device 20 at the time of braking the engine 1 described above, specifically, the control procedure of the turbo motor 24 at the time of braking of the engine 1 will be described with reference to FIG. As shown in FIG. 2, while the engine 1 is operating (while the vehicle is running), the ECU 40 constantly monitors the operation state of the accelerator pedal AP by the user and the like, and the regenerative generator 30 brakes the engine 1. Is determined (S10). If it is determined in S10 that the regenerative generator 30 is not performing regenerative operation, the ECU 40 stops the turbo motor 24 in S12 (if the electric motor 24 has been stopped until then, the ECU 40 stops the operation. Leave it alone) and return to the original standby state.
[0029]
On the other hand, if the ECU 40 determines in step S10 that the regenerative generator 30 is performing regenerative operation and the battery 31 is being charged via the inverter 25, the ECU 40 further supplies an ammeter for the battery 31 (not shown). It is determined whether the battery 31 is fully charged based on a signal from a voltmeter or the like (S14). If the ECU 40 determines in step S14 that the battery 31 is in a fully charged state, the ECU 40 further detects the rotation shaft 23 (turbine impeller) based on a detection value of a rotation speed sensor (not shown) provided in the supercharging device 20. It is determined whether the rotation speed of the compressor 21 and the compressor impeller 22) is equal to or less than a predetermined allowable value (S16). When the ECU 40 determines in S16 that the rotation speed of the rotating shaft 23 is equal to or less than the allowable value, the ECU 40 drives the turbo motor 24 of the supercharger 20 using the regenerative power collected by the regenerative generator 30. Command signal to the inverter unit 25 (S18).
[0030]
As described above, in the supercharger 20, when the battery 31 that can be charged using the regenerative power collected by the regenerative generator 30 is in the fully charged state, basically, the regenerative power collected by the regenerative generator 30 Are used to drive a turbo motor 24 connected to the compressor impeller 22. Thereby, according to the supercharging device 20, when the regenerative generator 30 is performing a regenerative operation so as to decelerate the engine 1 and the battery 31 is in a fully charged state, the regenerative generator 30 By effectively using the recovered regenerative electric power, the pressure of the intake air of the engine 1 can be increased.
[0031]
As a result, according to the present invention, it is possible to greatly improve the responsiveness of the supercharger 20 when an acceleration request is made after the engine 1 is decelerated. Also, by operating the turbo motor 24 from the time of deceleration regeneration and rotating the compressor impeller 22 (and the turbine impeller 21), the power itself required to drive the turbo motor 24 can be reduced by an acceleration request. This can be reduced compared to the case where the turbo motor 24 is quickly operated from the point in time when the operation is performed. If it is determined in S16 that the rotation speed of the rotating shaft 23 of the supercharging device 20 is higher than the allowable value, the process of the ECU 40 proceeds to S12 and drives the turbo motor 24 using the regenerative electric power. Is not executed.
[0032]
On the other hand, when it is determined in S14 that the battery is not in the fully charged state, the ECU 40 determines whether the regenerative power collected by the regenerative It is determined whether or not the surplus power before charging is exceeded, that is, whether or not the regenerative power collected by the regenerative generator 30 exceeds the specified charging power of the battery 31 (battery charging limit) (S20). If the ECU 40 determines in S20 that the regenerative power exceeds the specified charging power for the battery 31, it determines in S16 whether the rotation speed of the rotating shaft 23 of the supercharger 20 is equal to or less than a predetermined allowable value. Determine whether or not.
[0033]
When the ECU 40 determines in S16 that the rotation speed of the rotating shaft 23 is equal to or less than the allowable value, the ECU 40 drives the turbo motor 24 of the supercharger 20 using the regenerative power collected by the regenerative generator 30. Command signal to the inverter unit 25 (S18). As a result, since the charge power exceeds the specified charge power of the battery 31, it is possible to increase the pressure of the intake air of the engine 1 by effectively using the surplus regenerative power that cannot be used for charging the battery 31. It becomes. Note that the battery 31 is not in the fully charged state, the regenerative power exceeds the specified charging power of the battery 31, and in S16, the rotation speed of the rotating shaft 23 of the supercharger 20 exceeds the allowable value. When the determination is made, the process of the ECU 40 proceeds to S12, and the drive of the turbo motor 24 using the regenerative electric power is not executed.
[0034]
Here, during the operation of the engine 1, the ECU 40 monitors the frequency of rapid deceleration and rapid acceleration in the engine 1 by storing information on the opening degree of the throttle valve 12 at the time of acceleration and creating a database. . When the ECU 40 determines in S20 that the regenerative power does not exceed the specified charging power of the battery 31, the ECU 40 determines whether the acceleration / deceleration frequency in the engine 1 exceeds a predetermined frequency, that is, the engine 1 It is determined whether the frequency of the request for acceleration or rapid deceleration exceeds a predetermined frequency (S22).
[0035]
If the ECU 40 determines in S22 that the frequency of the request for rapid acceleration / deceleration in the engine 1 exceeds a predetermined frequency, that is, determines that the frequency of rapid acceleration / deceleration is high, the ECU 40 proceeds to S16. It is determined whether the rotation speed of the rotation shaft 23 is equal to or less than a predetermined allowable value. If the rotation speed of the rotation shaft 23 is determined to be equal to or less than the allowable value, the rotation speed is collected by the regenerative generator 30. A command signal is given to the inverter unit 25 to drive the turbo motor 24 of the supercharger 20 using the regenerative electric power (S18).
[0036]
Thus, in the engine 1, when the frequency of rapid acceleration / deceleration is high, the turbo motor 24 is driven by the regenerative power regardless of the state of charge of the battery 31. As a result, in the case where the engine 1 is decelerated and there is a high possibility that the engine 1 will be re-accelerated later, the turbo motor 24 can be operated in advance to increase the pressure of the intake air. Responsiveness of the supercharging device 20 can be improved extremely favorably.
[0037]
In S22, if it is determined that the frequency of the request for rapid acceleration / deceleration in the engine 1 does not exceed the predetermined frequency, that is, if it is determined that the frequency of rapid acceleration / deceleration is low, the process of the ECU 40 proceeds to S12. The driving of the turbo motor 24 using the regenerative electric power is not executed. Even if it is determined in S22 that the frequency of rapid acceleration / deceleration is high, if it is determined in S16 that the rotation speed of the rotating shaft 23 of the supercharging device 20 exceeds the allowable value, the processing of the ECU 40 is performed. Proceeds to S12, and the driving of the turbo motor 24 using the regenerative electric power is not executed.
[0038]
The regenerative generator 30 regenerates the energy that can be consumed by driving the turbo motor 24 and charging the battery 31, and it goes without saying that the insufficient braking force is generated by the hydraulic brake unit. When a slow acceleration request is made while the turbo motor 24 is operating, the ECU 40 controls the throttle valve 12 so as not to generate excessive torque according to a map or the like created in advance so that the intake is controlled. Reduce air volume. Further, when a sudden acceleration request is made in a state where the turbo motor 24 is operating, the ECU 40 controls the throttle valve 12 according to the supercharging pressure and the required torque while following a map or the like created in advance. I do.
[0039]
【The invention's effect】
As described above, according to the present invention, it is possible to improve the responsiveness to an acceleration request by effectively using the energy recovered from the engine.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an engine to which a supercharging device according to the present invention is applied.
FIG. 2 is a flowchart for explaining the operation of the supercharging device according to the present invention when braking the engine of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 20 Supercharger 21 Turbine impeller 22 Compressor impeller 23 Rotary shaft 24 Turbo motor 25 Inverter unit 30 Regenerative generator 31 Battery

Claims (4)

The present invention is applied to an engine including a regenerative generator and a battery that can be charged using regenerative power recovered by the regenerative generator, and rotationally drives a compressor element by a turbine element that is rotated by exhaust gas of the engine. A supercharger for compressing intake air by a compressor element,
An electric motor coupled to the compressor element and capable of rotationally driving the compressor element;
Control means for driving the electric motor by regenerative power collected by the regenerative generator when the battery is in a fully charged state. When the regenerative power recovered by the regenerative generator exceeds the marginal power until the battery is fully charged, the control unit drives the motor with the regenerative power regardless of the state of charge of the battery. The supercharging device according to claim 1, wherein: The control means monitors the acceleration / deceleration frequency of the engine, and when the acceleration / deceleration frequency exceeds a predetermined frequency, the electric motor is driven by the regenerative electric power regardless of the state of charge of the battery. The supercharging device according to claim 1, wherein the charging is performed. The present invention is applied to an engine including a regenerative generator and a battery that can be charged using regenerative electric power collected by the regenerative generator.The exhaust of the engine rotates a turbine element to rotationally drive a compressor element. In a method of supercharging an engine, in which intake air is compressed by a compressor element,
An electric motor is connected to the compressor element, and when the battery is in a fully charged state, the electric motor is driven by using regenerative power recovered by the regenerative generator. Method.

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