JP3922155B2 - Internal combustion engine cooled by a supercharger with electric means - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine provided with a supercharger that is also driven by electric means.
[0002]
[Prior art]
[Patent Document 1]
JP 2001-271663 A [Patent Document 2]
JP, 11-182256, A An exhaust purification catalyst provided in an exhaust system of an internal-combustion engine sometimes becomes overheated. In an internal combustion engine equipped with an electromagnetically driven intake / exhaust valve to cope with this problem, when the temperature of the exhaust purification catalyst rises above a predetermined value, either the opening / closing timing of the exhaust valve or the head Or it is proposed in said Unexamined-Japanese-Patent No. 2001-271663 to change both and to reduce exhaust temperature. On the other hand, as the operation of the internal combustion engine has been electronically controlled using a computer, electric means have been incorporated into a turbocharger that has conventionally only driven a compressor with an exhaust turbine, and the supercharging is Such correction control is known as disclosed in Japanese Patent Application Laid-Open No. 11-182256, for example.
[0003]
[Problems to be solved by the invention]
The present invention requires not only an exhaust purification catalyst but also an internal combustion engine to prevent any portion of a high-temperature working medium flow path in an internal combustion engine including a cylinder head from becoming overheated. The object is to achieve by effectively using the supercharger with electric means without hindering the output operation.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a supercharger with electric means, first control means for executing fuel cut when a predetermined operating condition is established, and the supercharger when fuel cut is executed. Second control means for operating the feeder by the electric means, and the second control means is when the temperature of the predetermined portion of the working medium flow path is equal to or higher than a predetermined threshold during fuel cut. The operation of the supercharger by the electric means is started and the operation state of the internal combustion engine, or the operation state of the vehicle when the internal combustion engine is an internal combustion engine of the vehicle, is determined by the cooling scavenging amount determined in consideration of the operation state. The portion of the working medium flow path that needs to be cooled is cooled, and the cooling scavenging amount determined in consideration of the operating state of the internal combustion engine is increased as the engine speed increases, and the vehicle operating state is taken into account. The amount of cooling and scavenging determined in accordance with the increase in vehicle speed is reduced, or the operation of the supercharger by the electric means during fuel cut by the second control means is not less than a predetermined number of revolutions of the internal combustion engine. An internal combustion engine characterized by being suppressed when the vehicle speed or the vehicle speed is not equal to or higher than a predetermined vehicle speed is provided.
[0005]
In this case, the second control means may be such performs control opening the intake throttle valve when actuated by said electric drive means the supercharger.
[0006]
Further, regarding the operation control of the supercharger by the electric means, the second control means is determined in consideration of the operation state of the internal combustion engine so that , for example, the cooling scavenging amount is increased as the engine speed increases. The supercharger may be operated by the electric means during a fuel cut by the amount of cooling scavenging, and the internal combustion engine may be configured to reduce the amount of cooling scavenging in response to an increase in vehicle speed. When the engine is an engine, the second control means may be operated by the electric means of the supercharger during a fuel cut by a cooling scavenging amount determined in consideration of the operating state of the vehicle. .
[0007]
[Action and effect of the invention]
The internal combustion engine provided with the supercharger with electric means further includes a first control means for executing fuel cut when a predetermined operating condition is satisfied, and the supercharger by the electric means when fuel cut is executed. A second control means for operating the supercharger when the temperature of a predetermined portion of the working medium flow path is equal to or higher than a predetermined threshold during the fuel cut. The working medium flow path is cooled by a cooling scavenging amount determined in consideration of the operating state of the internal combustion engine by starting the operation by means , or the operating state of the vehicle when the internal combustion engine is an internal combustion engine of a vehicle. The cooling scavenging amount that is determined in consideration of the operating state of the internal combustion engine is increased as the engine speed increases, and is determined in consideration of the vehicle operating state. Is reduced as the vehicle speed increases, or the operation of the supercharger by the electric means during fuel cut by the second control means is performed when the rotational speed of the internal combustion engine is not less than the predetermined rotational speed or when the vehicle speed is the predetermined vehicle speed. If it is suppressed when it is not above, the turbocharger is driven by electric means without interfering with the output operation required for the internal combustion engine using the period during inertial rotation of the internal combustion engine by fuel cut. In addition, portions of the working medium flow path that are sometimes superheated, such as the cylinder head and the exhaust purification catalyst, can be cooled by the air flow. In this case, the supercharger is actuated by the electric means under the control of the second control means, and cooling of a predetermined portion of the working medium flow path such as the cylinder head portion or the exhaust purification catalyst is performed. Since the temperature of the parts is started when the temperature is equal to or higher than a predetermined threshold, cooling of the parts by operating the supercharger by electric means is performed only when it is truly effective. As a result, the power consumption of the power storage device required for the operation of the electric means can be suppressed to the minimum necessary level.
[0008]
In this case, in particular, if the second control means performs control to open the intake throttle valve when the supercharger is operated by the electric means, the intake system is activated by the operation of the supercharger by the electric means. Thus, the air flow from the combustion chamber to the exhaust system can be generated more reliably and effectively, and the cooling effect on the cylinder head portion and the exhaust purification catalyst by the air flow can be enhanced.
[0010]
In addition, cooling of predetermined parts such as the cylinder head part and the exhaust purification catalyst is effective to be started when the temperature exceeds a predetermined threshold in order to protect the predetermined parts from overheating. Since the temperature of these parts decreases when cooling is started, there is room for consideration as to how much cooling scavenging is performed, that is, when the cooling is stopped. In this regard, if the second control means is operated by the electric means of the supercharger during the fuel cut by a cooling scavenging amount determined taking into account the operating state of the internal combustion engine, The supercharger can be electrically operated by an appropriate amount of cooling and scavenging based on the operating state of the internal combustion engine that has reached the temperature at which the predetermined part starts cooling, and the supercharger electric operation amount is set to the optimum value. Can be controlled. The cooling scavenging amount may be controlled as an operation time as one embodiment.
[0011]
Further, when the internal combustion engine is an internal combustion engine of a vehicle, the second control means operates the electric power of the supercharger during the fuel cut by a cooling scavenging amount determined in consideration of the operation state of the vehicle. If so, the supercharger can be electrically operated by an appropriate amount of cooling and scavenging based on the operating state of the vehicle that has reached the temperature at which the predetermined portion starts to cool. Thus, the supercharger electric operation amount can be controlled to the optimum value. Such cooling scavenging amount control may also be controlled as an operation time as one embodiment thereof.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 attached herewith is a schematic view showing the configuration of the main part of one embodiment of an internal combustion engine provided with a supercharger with a rotating electric machine according to the present invention. In the figure, 10 is a cylinder chamber of the internal combustion engine, 12 is a piston that reciprocates in the cylinder chamber, and 14 is a piston rod. An intake port 16 and an exhaust port 18 are provided at the top of the cylinder chamber 10 and are controlled to be opened and closed by an electromagnetically operated intake valve 20 and an exhaust valve 22, respectively. Reference numeral 24 is a fuel injection valve, and 26 is a spark plug.
[0013]
The exhaust port 18 is connected to a cochlear chamber 32 of the turbine section of the supercharger 30 via an exhaust pipe 28. The exhaust gas of the internal combustion engine introduced into the cochlear chamber 32 is blown around the turbine rotor 34 and passes through the radial vanes 36 to the turbine outlet port 38 while exerting a circumferential force on the turbine rotor. This is driven to rotate. The exhaust gas is then discharged to the atmosphere via the catalytic converter 40.
[0014]
The turbine rotor 34 is supported by a rotor shaft 42, and the rotor shaft 42 is supported from a frame of the supercharger by a bearing (not shown). A compressor impeller 44 is carried on the other end of the rotor shaft 42. When the compressor impeller 44 is driven by the turbine rotor 34, the air sucked into the intake pipe 48 through the air cleaner 46 is sucked from the compressor intake port 50 and is urged in the radial direction to the cochlear chamber 52 of the compressor. The air is compressed by being sent in, and is supplied to the intake port 16 through the intake pipe 54 as pressurized intake air. The intake pipe 54 is provided with an intercooler 56 and an intake throttle valve 58 on the way. Reference numeral 60 denotes an exhaust gas recirculation passage, which extracts a part of the exhaust gas from the middle of the exhaust pipe 28 under the control of the exhaust gas recirculation control valve 62 and introduces it into the intake pipe 54. Yes.
[0015]
In this embodiment, a rotor 66 of a rotating electric machine 64 configured as a motor generator is mounted on the rotor shaft 42 of the supercharger 30, and cooperates with a stator 68 disposed around the rotor 66. It can operate as an electric motor that electrically drives the rotor shaft 42 or as a generator that generates electric power when the rotor shaft 42 is driven by the turbine rotor 34.
[0016]
Reference numeral 70 denotes an electronic control unit (ECU) incorporating a microcomputer, and a series of signals S necessary for controlling the operation of the engine, such as engine speed, accelerator pedal depression amount, vehicle speed, etc., from various sensors not shown in the figure. , A signal related to the intake pressure at the compressor outlet from the intake pressure sensor 72, a signal related to the engine temperature, particularly the temperature of the cylinder head of the engine, from the engine temperature sensor 74, and a signal related to the temperature of the exhaust purification catalyst from the catalyst temperature sensor 76. Is provided to control the overall operation of the internal combustion engine, to perform fuel cut by closing the fuel injection valve 24 according to the present invention, and to control electric operation of the rotating electrical machine 64 related thereto.
[0017]
FIG. 2 is a flowchart showing one embodiment of the control mode relating to the supercharger electric operation of the internal combustion engine shown in FIG. 1 in the case of the vehicle internal combustion engine. The control according to the flowchart is started simultaneously with the start of operation of the internal combustion engine, and is repeated in a predetermined cycle such as several tens of milliseconds.
[0018]
When control is started, it is first determined in step 1 whether or not fuel cut has started. Whether or not to perform fuel cut is determined by the electronic control unit 70 based on the above-described accelerator pedal depression amount, vehicle speed, and other information related to engine operation control. There are various ways of thinking about when to perform fuel cut, but since it is well known in the field of this technology, its details are omitted. While the answer is no, control reaches the end and one cycle of control ends. When fuel cut is started and the answer to step 1 turns from no to yes, control proceeds to step 2.
[0019]
In step 2, it is determined whether or not the rotational speed Ne of the internal combustion engine is equal to or less than a predetermined threshold value Nea. While the answer is no, that is, when the internal combustion engine is in a high speed rotation state of a certain level or higher, priority is given to an engine brake that restricts the flow of air into the cylinder and provides resistance to the rotation of the engine. It is determined that the cooling of the cylinder head and the exhaust purification catalyst by the electric operation of the feeder is unnecessary or inappropriate, and the control proceeds to the end as it is, and the control for one cycle is completed. If the answer is yes, control proceeds to step 3.
[0020]
In step 3, it is determined whether or not the vehicle speed Vs is equal to or higher than a predetermined threshold value Vsa. When the answer is no, the control reaches the end as it is, and the control for one cycle is completed. That is, when the vehicle is not in a fuel cut state and the engine speed is equal to or less than a predetermined threshold and the vehicle is not traveling at a certain speed, the engine or the exhaust purification catalyst according to the present invention is electrically operated by the supercharger. No cooling is performed. If the answer is yes, control proceeds to step 4.
[0021]
In Step 4, it is determined whether or not the engine temperature Tc1 detected by the engine temperature sensor 74 is equal to or higher than a predetermined threshold value Tm1 in the embodiment of the engine shown in FIG. The threshold value Tm1 is such a temperature that the cylinder head portion is overheated when the temperature detected by the engine temperature sensor 74 exceeds this temperature, and it is desired to lower the temperature. If the answer is yes, control proceeds directly to step 5. If the answer is no, control proceeds to step 6.
[0022]
In step 6, similarly to the embodiment of the engine shown in FIG. 1, it is determined whether or not the temperature Tc2 of the exhaust purification catalyst detected by the exhaust purification catalyst temperature sensor 76 is not less than a predetermined threshold value Tm2. To be judged. This threshold value Tm2 is such a temperature that the exhaust purification catalyst is overheated when the temperature detected by the exhaust purification catalyst temperature sensor 76 exceeds this temperature, and it is desired to lower the temperature. If the answer is yes, control proceeds to step 5; if the answer is no, control ends and the control cycle ends.
[0023]
In step 5, the supercharger is used to cool the cylinder head and the exhaust purification catalyst on the basis of appropriate information regarding the outside air temperature and the operating state of the internal combustion engine and the vehicle inputted by the electronic control unit 70. A supercooling scavenging amount to be scavenged by the electric operation of is calculated. As one embodiment, the supercooling cooling scavenging amount is a value obtained by multiplying a certain basic amount by an assist coefficient α based on the engine speed and an assist coefficient β based on the vehicle speed as shown in FIGS. May be. The supercharging cooling scavenging amount calculated in this way is converted into the operation time of the supercharger in this embodiment, and a timer is set in step 7 based on this.
[0024]
Control then proceeds to step 8 where it is determined whether or not the time set by the timer has elapsed (timeout). If the answer is no, control proceeds to step 9 where it is determined whether fuel cut is ongoing. If the answer is yes, the control proceeds to step 10 where the intake throttle valve 58, the intake valve 20, and the exhaust valve 22 are opened, and the control for electrically operating the supercharger 30 with the rotating electrical machine 64 is started.
[0025]
Note that the opening control of the intake throttle valve 58, the intake valve 20, and the exhaust valve 22 is controlled according to the present invention depending on the mode of opening / closing control of these valves in the internal combustion engine. It is not always necessary as a part. In other words, if the intake throttle valve 58 is opened in association with the fuel cut, or if it is opened so as to open freely according to the flow of the intake during the fuel cut, the fuel cut control is performed. Therefore, control for opening the intake throttle valve 58 anew for the implementation of the present invention is unnecessary. Further, the opening of the intake valve 20 and the exhaust valve 22 may not be performed again for the implementation of the present invention as long as this is also included in the fuel cut control, and the intake valve and the exhaust valve are in accordance with the present invention. It does not necessarily have to be opened for supercharging cooling scavenging, but may be opened and closed as the engine rotates. However, in the case where the intake valve and the exhaust valve are electromagnetically operated as in the embodiment shown in FIG. 1, it is easily opened by the control of the electronic control unit 70, so that is performed as an embodiment. It is something like that.
[0026]
Control then returns to before step 8 and proceeds to step 10 until the time set by the timer elapses and the timer times out or the fuel cut is stopped before that. The valve 58, the intake valve 20, and the exhaust valve 22 are opened and the electric operation by the rotating electric machine 64 of the supercharger 30 is continued.
[0027]
Thus, while scavenging by the electric operation of the turbocharger is continued, the timer times out and the answer of step 8 turns to yes, or the fuel cut is stopped before the timer expires and the answer of step 9 is If the answer is no, the control proceeds to step 11 where the intake throttle valve 58, the intake valve 20, and the exhaust valve 22 are released, and the electric operation of the turbocharger for scavenging according to the present invention is also released.
[0028]
While the present invention has been described in detail with respect to one embodiment thereof, it will be apparent to those skilled in the art that various modifications can be made within the scope of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the configuration of the main part of an embodiment of an internal combustion engine equipped with a supercharger with a rotating electric machine according to the present invention.
FIG. 2 is a flowchart showing one embodiment in the case of an internal combustion engine for a vehicle of a control mode related to a supercharger electric operation according to the present invention of the internal combustion engine shown in FIG. 1;
FIG. 3 is a graph showing an example of one coefficient in calculation of a supercharging cooling scavenging amount;
FIG. 4 is a graph showing an example of another coefficient in the calculation of the supercharging cooling scavenging amount.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Cylinder chamber, 12 ... Piston, 14 ... Piston rod, 16 ... Intake port, 18 ... Exhaust port, 20 ... Intake valve, 22 ... Exhaust valve, 24 ... Fuel injection valve, 26 ... Spark plug, 28 ... Exhaust pipe, DESCRIPTION OF SYMBOLS 30 ... Supercharger, 32 ... Cochlear chamber of turbine part, 34 ... Turbine rotor, 36 ... Radial vane, 38 ... Turbine outlet port, 40 ... Catalytic converter, 42 ... Rotor shaft, 44 ... Compressor impeller, 46 ... Air cleaner , 48 ... Intake pipe, 50 ... Compressor intake port, 52 ... Compressor cochlear chamber, 54 ... Intake pipe, 56 ... Intercooler, 58 ... Intake throttle valve, 60 ... Exhaust gas recirculation passage, 62 ... Exhaust gas Recirculation control valve, 64 ... rotating electric machine, 66 ... rotor, 68 ... stator, 70 ... electronic control unit, 72 ... intake pressure sensor, 74 ... engine temperature sensor, 76 ... catalyst temperature sensor

Claims (9)

  A supercharger with electric means, first control means for executing fuel cut when a predetermined operating condition is satisfied, and second control for operating the supercharger with the electric means when fuel cut is executed And the second control means starts the operation of the supercharger by the electric means when the temperature of a predetermined portion of the working medium flow path is equal to or higher than a predetermined threshold during fuel cut. The cooling scavenging amount determined by taking into account the operating state of the internal combustion engine by cooling the portion that requires cooling of the working medium flow path by the cooling scavenging amount determined taking into account the operating state of the internal combustion engine Is an internal combustion engine that is adapted to increase with an increase in engine speed.   An internal combustion engine for a vehicle, wherein a supercharger with electric means, first control means for executing fuel cut when a predetermined operating condition is satisfied, and the supercharger when the fuel cut is executed Second control means operated by the means, and the second control means is configured to control the supercharger when the temperature of a predetermined portion of the working medium flow path is equal to or higher than a predetermined threshold during fuel cut. The operation by the electric means is started to cool the portion that requires cooling of the working medium flow path by a predetermined amount of cooling scavenging taking into consideration the driving state of the vehicle, and taking into account the driving state of the vehicle. An internal combustion engine characterized in that the cooling and scavenging amount determined in accordance with the vehicle speed is reduced as the vehicle speed increases.   An internal combustion engine for a vehicle, wherein a supercharger with electric means, first control means for executing fuel cut when a predetermined operating condition is satisfied, and the supercharger when the fuel cut is executed Second control means operated by the means, and the second control means is configured to control the supercharger when the temperature of a predetermined portion of the working medium flow path is equal to or higher than a predetermined threshold during fuel cut. The operation by the electric means is started to cool a portion requiring cooling of the working medium flow path, and the operation of the supercharger by the electric means during the fuel cut by the second control means is the rotation of the internal combustion engine. An internal combustion engine that is suppressed when the number is not less than a predetermined number of revolutions or when the vehicle speed is not more than a predetermined vehicle speed.   4. The internal combustion engine according to claim 1, wherein the second control means performs control to open an intake throttle valve when the supercharger is operated by the electric means. 5.   The second control means performs the operation by the electric means of the supercharger during a fuel cut by a cooling scavenging amount determined in consideration of the operating state of the internal combustion engine. 3. The internal combustion engine according to 3.   6. The internal combustion engine according to claim 5, wherein the amount of cooling scavenging determined in consideration of the operating state of the internal combustion engine is increased in accordance with an increase in engine speed.   The said 2nd control means performs the action | operation by the said electric means of the said supercharger during a fuel cut only by the cooling scavenging amount determined in consideration of the driving | running state of this internal combustion engine. The internal combustion engine described.   The internal combustion engine is an internal combustion engine of a vehicle, and the operation of the supercharger by the electric means during fuel cut by the second control means is performed when the rotational speed of the internal combustion engine is not less than a predetermined rotational speed or when the vehicle speed is a predetermined vehicle speed. The internal combustion engine according to any one of claims 2 to 7, wherein the internal combustion engine is suppressed when it is not above.   The internal combustion engine is an internal combustion engine of a vehicle, and the second control means operates the electric power of the supercharger during a fuel cut by a cooling scavenging amount determined in consideration of the operation state of the vehicle. The internal combustion engine according to claim 4, wherein the internal combustion engine is performed.

Images