JP2018080634A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an internal combustion engine mounted with an exhaust turbine type supercharger to curb a reduction in energy efficiency.SOLUTION: An internal combustion engine 1 comprises a turbocharger 4 which performs supercharging of air in an intake passage 3 using a flow of exhaust in an exhaust passage 9. The intake passage 3 has an impeller 6 connected to a motor generator 5. When actual supercharging pressure of the internal combustion engine 1 is higher than target supercharging pressure determined on the basis of output torque required for the internal combustion engine 1, the motor generator 5 is controlled through an electronic control device 16 so that the same generates power by functioning as a generator and thereby reducing pressure in the intake passage at a downstream side of the generator. When the motor generator 5 functions as the generator, the pressure of the air in the intake passage 3 at the downstream side of the impeller 6 is reduced as the impeller 6 is rotated with the air in the intake passage 3 passed therethrough. Also, electric energy can be recovered.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an internal combustion engine.

  As an internal combustion engine, an engine having an exhaust turbine supercharger that supercharges air in an intake passage using exhaust gas is known (see Patent Document 1). In such an internal combustion engine, the energy efficiency of the engine can be increased as much as the energy of the exhaust is recovered by being used for supercharging the air in the intake passage.

  Further, in an internal combustion engine having an exhaust turbine-type supercharging pressure, in order to suppress an excessive increase in the supercharging pressure, a bypass passage for flowing exhaust to bypass the turbine wheel of the supercharger, and the bypass passage are provided. A wastegate valve that opens and closes. When the supercharging pressure becomes too high, the waste gate valve is opened and a part of the exhaust gas of the internal combustion engine is caused to flow through the bypass passage so that the exhaust gas bypasses the turbocharger turbine wheel. . In this case, since the supercharging of the air in the intake passage of the internal combustion engine by the supercharger is suppressed, the excessive increase in the supercharging pressure is suppressed.

Japanese Patent No. 4168925

  In the internal combustion engine, by opening the waste gate valve, the supercharging of the air in the intake passage due to the supercharging pressure is suppressed, and the supercharging pressure is prevented from excessively rising. However, by opening the waste gate valve, the energy of the exhaust gas passing through the bypass passage cannot be recovered for supercharging by the supercharger, and the energy efficiency of the internal combustion engine is reduced accordingly. Become.

  The objective of this invention is providing the control apparatus of the internal combustion engine which can suppress the fall of energy efficiency in the internal combustion engine provided with the exhaust-turbine supercharger.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A control device for an internal combustion engine that solves the above-described problems is applied to an internal combustion engine that includes an exhaust turbine supercharger that supercharges air in an intake passage using exhaust gas. The apparatus also includes a generator that can generate power by being driven through the flow of air in the intake passage of the internal combustion engine. Further, the apparatus is configured to generate power by the generator when the actual supercharging pressure of the internal combustion engine is higher than a target supercharging pressure determined based on an output torque required for the engine. The control part which controls is also provided.

  According to this configuration, when the actual supercharging pressure of the internal combustion engine is higher than the target supercharging pressure, the generator is controlled so that power generation is performed using the air flow in the intake passage, and accordingly, the intake passage The pressure in the downstream portion of the generator in the interior decreases. Therefore, it is possible to suppress the actual supercharging pressure of the internal combustion engine from becoming too high, and it is possible to suppress a decrease in the energy efficiency of the internal combustion engine from the recovery of electric energy through the power generation.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of energy efficiency can be suppressed in the internal combustion engine provided with the exhaust-turbine supercharger.

1 is a schematic diagram showing an internal combustion engine to which a control device of the present embodiment is applied. The flowchart which shows the execution procedure of the drive control of a motor generator.

Hereinafter, an embodiment of a control device for an internal combustion engine will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, a compressor wheel 4 a of an exhaust turbine supercharger (turbocharger) 4 is provided in an intake passage 3 connected to a combustion chamber 2 of an internal combustion engine 1. An impeller 6 connected to the motor generator 5 is provided in a portion upstream of the compressor wheel 4 a in the intake passage 3. The motor generator 5 functions as a generator or functions as an electric motor.

  An intercooler 7 and a throttle valve 8 are provided in order from the upstream in a portion on the downstream side of the compressor wheel 4 a in the intake passage 3. Then, air is supplied to the combustion chamber 2 of the internal combustion engine 1 through the intake passage 3, and an amount of fuel corresponding to the amount of the air is supplied. The engine 1 is driven. The exhaust gas after the combustion of the fuel in the combustion chamber 2 is sent out to an exhaust passage 9 connected to the combustion chamber 2.

  A turbine wheel 4 b of the turbocharger 4 is provided in the exhaust passage 9. When the exhaust gas flowing through the exhaust passage 9 passes through the turbine wheel 4b, the turbine wheel 4b rotates and the compressor wheel 4a also rotates. Through the rotation of the compressor wheel 4a, the inside of the intake passage 3 with respect to the combustion chamber 2 is rotated. The air is supercharged.

  The turbocharger 4 includes a bypass passage 10 for flowing the exhaust gas so as to bypass the turbine wheel 4b by connecting the upstream portion and the downstream portion of the turbine wheel 4b in the exhaust passage 9 and the bypass passage 10. A waste gate valve 11 for opening and closing is provided. The waste gate valve 11 includes a valve body 12 that is provided in the bypass passage 10 and is displaced so as to make the gas flow area of the passage 10 variable, and a diaphragm 13 connected to the valve body 12. The diaphragm 13 defines an air chamber 14 that is open to the atmosphere and a pressure chamber 15 that is connected to a portion of the intake passage 3 between the compressor wheel 4 a and the throttle valve 8.

  The waste gate valve 11 is normally closed, and normally the valve body 12 is in a position where the gas flow area of the bypass passage 10 is set to “0”. However, if the pressure (supercharging pressure) between the compressor wheel 4a and the throttle valve 8 in the intake passage 3 becomes too high, the diaphragm 13 is elastically deformed based on the pressure difference between the pressure and the atmospheric pressure, and accordingly. The valve body 12 is displaced to a position where the gas flow area of the bypass passage 10 is larger than “0”. As a result, the bypass passage 10 is in a state where gas can flow (open state), and the exhaust gas passing through the turbine wheel 4b decreases as the exhaust gas passes through the bypass passage 10. Thereby, since the rotational speed of the turbocharger 4 (compressor wheel 4a) can be suppressed low, the supercharging pressure of the internal combustion engine 1 can be lowered.

Next, the electrical configuration of the control device for the internal combustion engine 1 will be described.
The apparatus includes an electronic control device 16 that controls various devices related to driving of the internal combustion engine 1. The electronic control device 16 receives a detection signal from an accelerator position sensor 18 that detects the depression amount of an accelerator pedal 17 operated by a user, and between the compressor wheel 4 a and the throttle valve 8 in the intake passage 3. A detection signal from a pressure sensor 19 for detecting the pressure (supercharging pressure) is input. In addition, the electronic control unit 16 outputs a command signal to each drive circuit of the inverter 21 and the converter 22 that controls input / output of electric power between the motor generator 5 and the battery 20, thereby causing the motor generator 5 to operate. It functions as a generator or as an electric motor.

  When the motor generator 5 functions as a generator, the impeller 6 is rotated by the flow of air in the intake passage 3 to drive the motor generator 5, thereby generating electric power. At this time, the inverter 21 and the converter 22 supply the battery 20 with electric power obtained by the power generation by the motor generator 5 to charge the battery 20. When the motor generator 5 functions as a generator, the air in the intake passage 3 passes through the impeller 6 and rotates the impeller 6, so that the downstream side of the impeller 6 in the intake passage 3 is rotated. The pressure of the air in the portion decreases, and as a result, the supercharging pressure of the internal combustion engine 1 also decreases. The electronic control unit 16 can adjust the power generation amount when the motor generator 5 generates power. Then, as the power generation amount of the motor generator 5 is increased, the decreasing tendency of the supercharging pressure in the internal combustion engine 1 increases.

  When the motor generator 5 functions as an electric motor, the impeller 6 is rotated by driving the motor generator 5, thereby assisting in supercharging the air in the intake passage 3. At this time, the inverter 21 and the converter 22 supply power from the battery 20 to the motor generator 5. When the motor generator 5 functions as an electric motor, the air in the intake passage 3 is supercharged to the combustion chamber 2 through the rotation of the impeller 6, thereby increasing the supercharging pressure of the internal combustion engine 1. The electronic control unit 16 can adjust the energization amount of the motor generator 5 when the motor generator 5 is driven as an electric motor. Then, as the energization amount of the motor generator 5 is increased, the rotational speed of the motor generator 5 (the impeller 6) is increased, and the increasing pressure of the supercharging pressure in the internal combustion engine 1 is increased.

Next, the operation of the control device for the internal combustion engine 1 will be described.
FIG. 2 is a flowchart showing an execution procedure of drive control of the motor generator 5 when the motor generator 5 is operated as a generator or an electric motor. The drive control of the motor generator 5 is executed through the electronic control device 16.

  The electronic control unit 16 calculates the output torque (requested output torque Tr) required for the internal combustion engine 1 based on the depression amount of the accelerator pedal 17 as the process of step 101 (S101) in FIG. Furthermore, the electronic control unit 16 refers to a target boost pressure that is a target value of the boost pressure of the internal combustion engine 1 with reference to a map that is determined in advance through experiments or the like based on the required output torque Tr in the subsequent processing of S102. Tq is calculated. The target boost pressure Tq calculated in this way becomes a value lower than the boost pressure when the waste gate valve 11 is opened. The electronic control unit 16 takes in the actual supercharging pressure (actual supercharging pressure Rq) of the internal combustion engine 1 obtained based on the subsequent processing of S103 and the detection signal from the pressure sensor 19. Thereafter, the process proceeds to S104.

  The electronic control unit 16 calculates the pressure difference Ep between the target boost pressure Tq and the actual boost pressure Rq using the following expression “Ep = Tq−Rq” as the process of S104, and the actual excess as the process of S105. It is determined whether or not the supply pressure Rq is higher than the target boost pressure Tq. If it is determined in S105 that the actual boost pressure Rq is higher than the target boost pressure Tq, the process proceeds to S106. The processes of S106 and S107 are for causing the motor generator 5 to function as a generator.

  The electronic control unit 16 calculates a power generation amount command value A as a power generation amount command value in the motor generator 5 based on the pressure difference Ep (<0) as a process of S106. The power generation amount command value A calculated in this way becomes larger as the pressure difference Ep is farther to the minus side with respect to “0”, in other words, as the actual boost pressure Rq is higher than the target boost pressure Tq. Is calculated. In step S107, the electronic control unit 16 drives the motor generator 5 as a generator based on the power generation amount command value A so that the power generation amount of the motor generator 5 is a value corresponding to the power generation amount command value A. To be. Thereafter, the electronic control unit 16 once ends this series of processing.

  On the other hand, if it is determined in S105 that the actual boost pressure Rq is equal to or lower than the target boost pressure Tq, the process proceeds to S108. The processing of S108 and S109 is for causing the motor generator 5 to function as an electric motor.

  The electronic control unit 16 calculates the energization amount command value B as the energization amount command value in the motor generator 5 based on the pressure difference Ep (≧ 0) as the process of S108. The energization amount command value B calculated in this way becomes larger as the pressure difference Ep is farther to the plus side with respect to “0”, in other words, as the actual boost pressure Rq is lower than the target boost pressure Tq. Is calculated. In step S109, the electronic control unit 16 drives the motor generator 5 as an electric motor based on the energization amount command value B, so that the energization amount of the motor generator 5 becomes a value corresponding to the energization amount command value B. Like that. Thereafter, the electronic control unit 16 once ends this series of processing.

According to the embodiment described in detail above, the following effects can be obtained.
(1) When the actual boost pressure Rq is higher than the target boost pressure Tq, the motor generator 5 is caused to function as a generator so that the motor generator 5 generates power using the air flow in the intake passage 3. . Thus, when the motor generator 5 functions as a generator, the air in the intake passage 3 passes through the impeller 6 and rotates the impeller 6, so that the downstream side of the impeller 6 in the intake passage 3. The air pressure in the part decreases. Therefore, the actual supercharging pressure Rq of the internal combustion engine 1, that is, the pressure (supercharging pressure) at the portion between the compressor wheel 4a and the throttle valve 8 in the intake passage 3 can be suppressed from becoming too high. Moreover, since the supercharging pressure of the internal combustion engine 1 does not become too high as described above, the waste gate valve 11 can be prevented from being opened, or can be quickly closed even if it is temporarily opened. This means that instead of opening the waste gate valve 11 and throwing away exhaust energy, the exhaust energy is used for supercharging by the turbocharger 4 and then recovered as electric energy through power generation by the motor generator 5. Means that. Since electric energy can be recovered through power generation by the motor generator 5 in this way, it is possible to suppress a reduction in energy efficiency of the internal combustion engine 1 as in the case where the waste gate valve 11 is opened.

  (2) When the motor generator 5 is caused to function as a generator as described above, the amount of power generated by the motor generator 5 is increased as the actual boost pressure Rq is higher than the target boost pressure Tq. As a result, the pressure in the portion of the intake passage 3 on the downstream side of the motor generator 5, in other words, the actual supercharging pressure Rq of the internal combustion engine 1 can be easily reduced, and the electric energy through the power generation by the motor generator 5 can be reduced. Recovery can be performed effectively.

  (3) When the actual supercharging pressure Rq is equal to or lower than the target supercharging pressure Tq, the motor generator 5 (impeller 6) assists supercharging of the air in the intake passage 3 by causing the motor generator 5 to function as an electric motor. Therefore, the actual boost pressure Rq can be raised to the target boost pressure Tq.

  (4) When the motor generator 5 is caused to function as an electric motor as described above, as the actual boost pressure Rq is lower than the target boost pressure Tq, the energization amount of the motor generator 5 is increased to increase the motor generator 5 (impeller). By increasing the rotational speed of 6), the actual boost pressure Rq can be quickly increased to the target boost pressure Tq.

  (5) Compared with the case where the generator and the motor are provided separately by making the motor generator 5 function as a generator or as an electric motor, parts are shared by the motor generator 5. The score can be reduced.

  (6) When the motor generator 5 is functioning as an electric motor, the air pressure in the downstream portion of the impeller 6 in the intake passage 3 is reduced as the air in the intake passage 3 passes through the impeller 6. Since the temperature decreases, the temperature of the air can be decreased. As a result, since the temperature of the air supplied to the combustion chamber 2 can be lowered, it becomes easier to improve the output of the internal combustion engine 1 and improve the fuel consumption.

In addition, the said embodiment can also be changed as follows, for example.
An electric actuator for opening and closing the waste gate valve 11 instead of opening and closing the waste gate valve 11 based on the pressure (supercharging pressure) at the portion between the compressor wheel 4a and the throttle valve 8 in the intake passage 3 Etc. may be provided. In this case, when the actual supercharging pressure Rq becomes higher than the target supercharging pressure Tq, the waste gate valve 11 is opened and the motor generator 5 is controlled so that the motor generator 5 generates power, and then the waste gate valve. 11 can be gradually closed.

  If the waste gate valve 11 and the motor generator 5 are operated as described above, when the actual boost pressure Rq becomes higher than the target boost pressure Tq, the waste gate valve 11 is opened and the motor generator 5 generates power. As a result, the actual boost pressure Rq can be quickly reduced to the target boost pressure Tq. Thereafter, by gradually closing the waste gate valve 11, the amount of power generated by the motor generator 5 can be gradually increased, whereby the electric energy can be recovered.

  The power generation amount command value A is calculated so as to increase as the actual supercharging pressure Rq increases with respect to the target supercharging pressure Tq. However, an optimal constant value obtained in advance through experiments or the like can be used. is there.

  The energization amount command value B is calculated so as to increase as the actual supercharging pressure Rq decreases with respect to the target supercharging pressure Tq. However, it is also possible to use an optimum constant value obtained in advance through experiments or the like. is there.

The motor generator 5 may function only as a generator.
Instead of providing the motor generator 5, a generator and an electric motor may be provided separately, and an impeller connected to the generator and an impeller connected to the electric motor may be provided in the intake passage 3, respectively.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Combustion chamber, 3 ... Intake passage, 4 ... Turbocharger, 4a ... Compressor wheel, 4b ... Turbine wheel, 5 ... Motor generator, 6 ... Impeller, 7 ... Intercooler, 8 ... Throttle valve, DESCRIPTION OF SYMBOLS 9 ... Exhaust passage, 10 ... Bypass passage, 11 ... Waste gate valve, 12 ... Valve body, 13 ... Diaphragm, 14 ... Atmosphere chamber, 15 ... Pressure chamber, 16 ... Electronic control unit, 17 ... Accelerator pedal, 18 ... Accelerator position Sensor, 19 ... Pressure sensor, 20 ... Battery, 21 ... Inverter, 22 ... Converter.

Claims (5)

In a control device for an internal combustion engine comprising an exhaust turbine supercharger that supercharges air in an intake passage using exhaust gas of the internal combustion engine,
A generator capable of generating electricity by being driven through the flow of air in the intake passage;
A control unit for controlling the generator so that power is generated by the generator when an actual supercharging pressure of the internal combustion engine is higher than a target supercharging pressure determined based on an output torque required for the engine; ,
A control device for an internal combustion engine, comprising:   When the actual supercharging pressure of the internal combustion engine is higher than the target supercharging pressure, the control unit increases the amount of power generated by the generator as the difference between the actual supercharging pressure and the target supercharging pressure increases. 2. The control device for an internal combustion engine according to claim 1, wherein the generator is controlled so as to increase. The exhaust turbine supercharger includes a bypass passage for flowing exhaust so as to bypass the turbine wheel of the turbocharger, and a waste gate valve for opening and closing the bypass passage,
When the actual boost pressure of the internal combustion engine becomes higher than the target boost pressure, the control unit opens the waste gate valve and controls the generator so that power is generated by the generator. 3. The control device for an internal combustion engine according to claim 2, wherein the waste gate valve is gradually closed. The generator is a motor generator that also functions as an electric motor that assists supercharging of air in the intake passage,
The control unit causes the motor generator to function as an electric motor to assist supercharging of air in the intake passage when an actual supercharging pressure of the internal combustion engine is equal to or less than the target supercharging pressure. The control apparatus for an internal combustion engine according to any one of claims 1 to 3.   When the actual boost pressure of the internal combustion engine is equal to or lower than the target boost pressure, the control unit increases the difference between the actual boost pressure and the target boost pressure. The control apparatus for an internal combustion engine according to claim 4, wherein the energization amount of the motor generator is controlled so that the rotation speed becomes high.

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