JP2008231944A - Swirl control device for on-vehicle internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a swirl control device for an on-vehicle internal combustion engine, capable of suppressing deterioration of a combustion state regardless of the operation condition of a supercharger. <P>SOLUTION: In an electronic control device 6 including a basic target swirl ratio calculating section 61, a target supercharging pressure calculating section 62, a correction efficient calculating section 63 and a swirl opening control section 64, a basic target swirl ratio Stb is calculated based on the rotational speed Ne of the on-vehicle internal combustion engine provided with the supercharger 5 and the target amount of fuel injected Qt. Also, a correction efficient Ks is calculated based on differential pressure ΔP obtained by subtracting an actual supercharging pressure PAc detected by a supercharging pressure sensor 91 from a target supercharging pressure PAt, and an actual injection pressure Pic detected by an injection pressure sensor 93. Then, a final target swirl ratio Stn is calculated by multiplying the basis target swirl ratio Stb by the correction efficient Ks, and the opening of a swirl control valve 23 arranged in an intake passage 2 is adjusted for materializing the final target swirl ratio Stn. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention calculates a target swirl ratio based on an operating state of an in-vehicle internal combustion engine equipped with a supercharger, and adjusts the opening degree of a swirl control valve provided in an intake passage to realize the target swirl ratio. The present invention relates to a swirl control device for an internal combustion engine.

Conventionally, as a swirl control device for this type of vehicle-mounted internal combustion engine, for example, there is one described in Patent Document 1. In the swirl control device for an in-vehicle internal combustion engine that has been generally adopted as such a control device, including the device described in Patent Document 1, a target swirl ratio is calculated based on the engine speed, and the target swirl ratio should be realized. The opening degree of the swirl control valve provided in the intake passage is adjusted. Here, the target swirl ratio is a value that determines the strength of the swirl. If the other parameters such as the engine speed that govern the intake characteristics are the same, the larger the swirl ratio, the more powerful swirl can be generated. it can. More specifically, the swirl ratio is calculated as a larger value as the engine rotational speed NE is lower and the intake flow rate of the intake air introduced into the cylinder is lower, so that an appropriate value is obtained according to the engine rotational speed NE. A strong swirl can be obtained, and the combustion state can be improved by sufficiently mixing the intake air and the fuel.
JP 2002-371856 A

  By the way, in an in-vehicle internal combustion engine equipped with a supercharger, since the intake air compressed by the supercharger is introduced into the cylinder, the operation of the supercharger is performed even if the engine speed NE is the same. The inflow speed of intake air varies depending on the state. For this reason, in the conventional swirl control apparatus, the swirl of moderate intensity | strength according to the operating state of a supercharger cannot be generated. As a result, intake air and fuel cannot be properly mixed, and the combustion state may be deteriorated.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a swirl control device for an on-vehicle internal combustion engine capable of suppressing deterioration of the combustion state regardless of the operating state of the supercharger. There is to do.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
According to the first aspect of the present invention, the target swirl ratio is calculated based on the operating state of the in-vehicle internal combustion engine provided with the supercharger, and the swirl control valve provided in the intake passage is opened to realize the target swirl ratio. The gist is to calculate the target swirl ratio based on the engine speed and the actual boost pressure detected by a boost pressure sensor in a swirl control device for an on-vehicle internal combustion engine that adjusts the degree.

  According to this configuration, since the target swirl ratio is calculated based on the engine speed and the actual supercharging pressure, the actual supercharging pressure changes according to the operating state of the turbocharger, and thereby the intake air flow Even if the speed changes, it is possible to generate a swirl having an appropriate strength according to the inflow speed of the intake air. For this reason, the intake air and the fuel can be appropriately mixed regardless of the operating state of the supercharger, and the deterioration of the combustion state can be suppressed. Here, the target swirl ratio is a value that determines the strength of the swirl. If the other parameters such as the engine speed that govern the intake characteristics are the same, the larger the swirl ratio, the more powerful swirl can be generated. it can.

  Specifically, as in the invention described in claim 2, by adopting a mode in which the target swirl ratio is increased as the actual supercharging pressure is lower, it is appropriately adapted to the change in the actual supercharging pressure. A target swirl ratio can be set.

  According to the invention of claim 3, the target boost pressure is calculated based on the engine rotational speed, and the target swirl ratio increases as the value obtained by subtracting the actual boost pressure from the target boost pressure increases. It is also possible to adopt a mode of increasing the value.

  According to a fourth aspect of the present invention, in the swirl control device for an in-vehicle internal combustion engine according to any one of the first to third aspects, the target swirl ratio is further calculated using the target fuel injection amount as a parameter. The gist is to increase the target swirl ratio as the actual injection pressure detected by the injection pressure sensor is lower.

  When calculating the target swirl ratio using the target fuel injection amount as a parameter in addition to the engine speed and the actual supercharging pressure, the target swirl ratio is set lower as the target fuel injection amount increases. However, when the actual injection pressure is lower than the assumed injection pressure, the actually injected fuel becomes smaller than the target fuel injection amount. For this reason, intake air and fuel cannot be mixed sufficiently, and the combustion state may be deteriorated.

  In this regard, according to the above configuration, the target swirl ratio is increased as the actual injection pressure is lower. For example, when the actual injection pressure is lower than the assumed injection pressure and less fuel is actually injected, the target swirl ratio is stronger. A swirl will be generated. Thereby, intake air and fuel can be sufficiently mixed, and deterioration of the combustion state can be suppressed.

  Hereinafter, an embodiment of a swirl control device for an in-vehicle internal combustion engine according to the present invention will be described in detail with reference to FIGS. In this embodiment, a diesel engine (hereinafter simply referred to as an engine) provided with an exhaust-driven supercharger will be described as an example.

  FIG. 1 is a schematic diagram showing the overall configuration of the engine and its control device of this embodiment. The engine is provided with a plurality of cylinders. In FIG. 1, only one of these cylinders is representatively illustrated.

  As shown in FIG. 1, the engine includes a cylinder head 1A, a cylinder block 1B, and an intake passage 2 and an exhaust passage 3 connected to the cylinder head 1A. Among these, the cylinder head 1 </ b> A is provided with a fuel injection valve 4 for directly injecting and supplying fuel into the combustion chamber. The electronic control device 6 controls the valve opening timing and the valve opening period.

  In the cylinder head 1A, two intake ports 21A and 21B connecting the intake passage 2 and the combustion chamber, and two exhaust ports 31A and 31B connecting the exhaust passage 3 and the combustion chamber are formed for each cylinder. Yes.

  Of these intake ports 21A and 21B, the first intake port 21A is provided with a swirl control valve 22 capable of adjusting the strength of the swirl according to the opening thereof. Be controlled. An intake pipe 23 provided with a compressor 51 for compressing intake air is connected to the intake upstream side of the intake ports 21A and 21B.

  On the other hand, an exhaust pipe 32 for exhausting the exhaust generated in the combustion chamber to the outside is connected to the exhaust downstream side of the exhaust ports 31A and 31B. The exhaust pipe 32 is provided with a turbine 52 that is rotationally driven by exhaust energy, and the rotation of the turbine 52 is transmitted to the compressor 51 via a shaft 53. The compressor 51, the turbine 52, and the shaft 53 constitute an exhaust drive type supercharger 5.

  Further, the engine and the vehicle on which the engine is mounted are provided with various sensors for detecting the engine operating state and the vehicle traveling state. The engine is provided with a supercharging pressure sensor 91 for detecting the actual supercharging pressure PAc. Further, a crank angle sensor 92 for detecting the engine speed NE and an injection pressure sensor 93 for detecting the pressure of the fuel supplied to the fuel injection valve 4, that is, the actual injection pressure Pic are provided.

  On the other hand, the vehicle is provided with an accelerator sensor 94 for detecting the amount of depression of the accelerator pedal, that is, the accelerator opening ACCP. The detection signals of these various sensors are taken into the electronic control device 6.

  The electronic control unit 6 performs various controls of the engine based on detection signals from various sensors, and specifically includes a basic target swirl ratio calculation unit 61, a target boost pressure calculation unit 62, and a correction coefficient calculation unit. 63, and the swirl opening degree control part 64 is comprised.

  Of these, the basic target swirl ratio calculation unit 61 calculates the basic target swirl ratio Stb based on the engine speed NE and the target fuel injection amount Qt at that time. Here, the basic target swirl ratio Stb is a value that determines the strength of the swirl. If other parameters such as the engine speed NE that govern the intake characteristics are the same, the larger the basic target swirl ratio Stb, the stronger the swirl ratio. Can be generated. The target fuel injection amount Qt is calculated based on the accelerator opening ACCP and the engine speed NE.

Further, the target boost pressure calculation unit 62 calculates the target boost pressure PAt based on the engine speed NE and the target fuel injection amount Qt at that time.
Further, the correction coefficient calculation unit 63 calculates the correction coefficient Ks based on the differential pressure ΔP obtained by subtracting the actual boost pressure PAc from the target boost pressure PAt at that time and the actual injection pressure Pic.

  Further, the swirl opening degree control unit 64 calculates the final target swirl ratio Stn by multiplying the basic target swirl ratio Stb by the correction coefficient Ks. Then, the opening degree of the swirl control valve 22 is adjusted so as to realize the final target swirl ratio Stn.

  FIG. 2 is a flowchart showing a specific processing procedure when performing the above-described swirl control executed through the electronic control unit 6. This series of processing is repeatedly executed by the electronic control device 6 with a predetermined period.

  As shown in FIG. 2, in this series of processes, first, as the process of step S101, the engine speed NE, the accelerator opening ACCP, the actual boost pressure PAc, and the actual injection pressure Pic at that time are read. Next, as a process of step S102, the basic target swirl ratio Stb is calculated based on the engine speed NE and the target fuel injection amount Qt. In a process different from this process, the target fuel injection amount Qt is calculated based on the engine speed NE and the accelerator opening ACCP. Next, as a process of step S103, the target boost pressure PAt is calculated based on the engine speed NE and the target fuel injection amount Qt. Then, as a process of step S104, a correction coefficient Ks is calculated based on the differential pressure ΔP obtained by subtracting the actual boost pressure PAc from the target boost pressure PAt and the actual injection pressure Pic. Then, as the process of step S105, the final target swirl ratio Stn is calculated by multiplying the basic target swirl ratio Stb by the correction coefficient Ks, and this process is temporarily terminated.

Next, characteristics of the calculation map for calculating the basic target swirl ratio Stb, the target boost pressure PAt, and the correction coefficient Ks will be described with reference to FIGS.
FIG. 3 is a graph showing the relationship between the engine speed NE and the target fuel injection amount Qt and the basic target swirl ratio Stb. As shown in FIG. 3, the basic target swirl ratio Stb decreases as the engine speed NE increases, and the basic target swirl ratio Stb decreases as the target fuel injection amount Qt increases.

  FIG. 4 is a graph showing the relationship between the engine speed NE and the target fuel injection amount Qt and the target boost pressure PAt. As shown in FIG. 4, the target boost pressure PAt increases as the engine speed NE increases, and the target boost pressure PAt increases as the target fuel injection amount Qt increases.

  FIG. 5 is a graph showing the relationship between the differential pressure ΔP obtained by subtracting the actual boost pressure PAc from the target boost pressure PAt, the actual injection pressure Pic, and the correction coefficient Ks. As shown in FIG. 5, the correction coefficient Ks increases as the differential pressure ΔP increases, and the correction coefficient Ks increases as the actual injection pressure Pic decreases.

According to the on-vehicle internal combustion engine control apparatus according to this embodiment described above, the effects listed below can be obtained.
(1) A correction calculated based on a differential pressure ΔP obtained by calculating a basic target swirl ratio Stb based on the engine rotational speed NE and the target fuel injection amount Qt and subtracting the actual boost pressure PAc from the target boost pressure PAt. The final target swirl ratio Stn is calculated by multiplying the basic target swirl ratio Stb by the coefficient Ks. That is, the final target swirl ratio Stn is calculated based on the engine rotational speed NE and the actual boost pressure PAc detected by the boost pressure sensor 91. Thereby, even if the actual supercharging pressure PAc changes according to the operating state of the supercharger 5 and the inflow speed of the intake air changes accordingly, a swirl having an appropriate strength according to the inflow speed of the intake air is generated. be able to. For this reason, regardless of the operating state of the supercharger 5, intake air and fuel can be mixed appropriately, and deterioration of the combustion state can be suppressed.

  (2) Since the correction coefficient Ks calculated based on the differential pressure ΔP obtained by subtracting the actual boost pressure PAc from the target boost pressure PAt increases as the differential pressure ΔP increases, the final value decreases as the actual boost pressure PAc decreases. The target swirl ratio Stn will be increased. For this reason, the target swirl ratio St can be appropriately set according to the change in the actual supercharging pressure PAc.

  (3) When calculating the final target swirl ratio Stn using the target fuel injection amount Qt as a parameter, the basic target swirl ratio Stb is set lower as the target fuel injection amount Qt increases. However, when the actual injection pressure Pic is lower than the assumed injection pressure Pit, the actually injected fuel is less than the target fuel injection amount Qt. For this reason, intake air and fuel cannot be mixed sufficiently, and the combustion state may be deteriorated.

  In this respect, in this embodiment, the final target swirl ratio Stn is increased by increasing the correction coefficient Ks multiplied by the basic target swirl ratio Stb as the actual injection pressure Pic is lower. For this reason, for example, when the actual injection pressure Pic is lower than the assumed injection pressure Pit and the amount of fuel actually injected is small, a stronger swirl is generated. Thereby, intake air and fuel can be mixed sufficiently, and deterioration of the combustion state can be suppressed.

  In addition, the swirl control device for the in-vehicle internal combustion engine according to the present invention is not limited to the configuration exemplified in the above-described embodiment, and may be implemented as, for example, the following form in which the embodiment is appropriately changed. You can also.

  In the above embodiment, the exhaust drive type supercharger 5 is illustrated, but the supercharger is not limited to this, and may be a mechanical drive type supercharger, a so-called supercharger. In this case, the swirl control may be executed only when the supercharger is operating. That is, when the supercharger is not in operation, the supercharging pressure is not controlled. Therefore, the opening degree of the swirl control valve 22 may be adjusted so as to realize the basic target swirl ratio Stb. Further, the present invention can be applied to an internal combustion engine that is not provided with a supercharger. That is, in this case, the target swirl ratio may be calculated based on the intake pressure and the engine speed NE instead of the actual supercharging pressure.

  In the above embodiment, the correction coefficient Ks is calculated based on the differential pressure ΔP obtained by subtracting the actual boost pressure PAc from the target boost pressure PAt and the actual injection pressure Pic, but the actual injection pressure Pic is In the case of an engine that does not vary greatly, the actual injection pressure Pic can be omitted as a parameter for calculating the correction coefficient Ks.

  In the above embodiment, the final target swirl ratio Stn is calculated by multiplying the basic target swirl ratio Stb by the correction coefficient Ks. However, the final target swirl ratio Stn is calculated based on the engine speed NE and the actual boost pressure PAc. The swirl ratio Stn may be directly calculated.

  -Although the diesel engine was illustrated in the said embodiment, an internal combustion engine is not restricted to this, This invention can also be applied with respect to the gasoline engine provided with the fuel injection valve which can be directly injected in a cylinder. However, the present invention can also be applied to a gasoline engine having a fuel injection valve capable of injecting and supplying fuel from the downstream of the swirl control valve at the intake port. In that case, it is desirable to add the opening of the throttle valve that adjusts the flow rate of the air flowing through the intake passage as one of the parameters for calculating the target swirl ratio.

The schematic diagram which showed the whole structure about one Embodiment of the swirl control apparatus of the vehicle-mounted internal combustion engine concerning this invention. The flowchart which showed the specific process sequence at the time of performing the swirl control performed through the control apparatus concerning the embodiment. The graph which showed the relationship between the engine speed NE and the target fuel injection amount Qt, and the basic target swirl ratio Stb. The graph which showed the relationship between the engine speed NE, the target fuel injection amount Qt, and the target boost pressure PAt. The graph which showed the relationship between the differential pressure (DELTA) P of supercharging pressure, the actual injection pressure Pic, and the correction coefficient Ks.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A ... Cylinder head, 1B ... Cylinder block, 2 ... Intake passage, 3 ... Exhaust passage, 4 ... Fuel injection valve, 5 ... Supercharger, 6 ... Electronic control unit, 21 ... Intake pipe, 22A ... First intake port, 22B ... Intake port, 23 ... Swirl control valve, 31 ... Exhaust pipe, 32A, 32B ... Exhaust port, 51 ... Compressor, 52 ... Turbine, 53 ... Shaft, 91 ... Supercharging pressure sensor, 92 ... Crank angle sensor, 93 ... Injection pressure sensor, 94 ... Accelerator sensor.

Claims (4)

A swirl for an in-vehicle internal combustion engine that calculates a target swirl ratio based on the operating state of the in-vehicle internal combustion engine equipped with a supercharger and adjusts the opening degree of a swirl control valve provided in the intake passage in order to realize the target swirl ratio In the control device,
A swirl control device for an on-vehicle internal combustion engine, characterized in that the target swirl ratio is calculated based on an engine rotation speed and an actual boost pressure detected by a boost pressure sensor. The swirl control device for an in-vehicle internal combustion engine according to claim 1,
The target swirl ratio is increased as the actual supercharging pressure is lowered. The swirl control device for the on-vehicle internal combustion engine according to claim 1 or 2,
A target boost pressure is calculated based on the engine rotational speed, and the target swirl ratio is increased as the value obtained by subtracting the actual boost pressure from the target boost pressure is increased. Control device. In the swirl control apparatus of the vehicle-mounted internal combustion engine as described in any one of Claims 1-3,
The target swirl ratio is further calculated using the target fuel injection amount as a parameter,
The swirl control device for an on-vehicle internal combustion engine, wherein the target swirl ratio is increased as the actual injection pressure detected by the injection pressure sensor is lower.

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