JP2001342840A - Control device for internal combustion engine with supercharger - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To always positively maintain a pressure ratio in the vicinity of a surging line without being affected by a change in atmospheric pressure. As a result, it is possible to obtain sufficient engine torque while preventing surging. Provided is a control device for a supercharged internal combustion engine. SOLUTION: The current operating position of the turbocharger is determined based on a pressure ratio πc and an air flow rate Q, and a plurality of surge limit pressure ratios πcs set in advance on a surging line S correspond to the current air flow rate Q. The surge limit pressure ratio πcs to be performed is determined, and the supercharging pressure of the turbocharger is controlled such that the difference Δπc between the surge limit pressure πcs and the pressure ratio πc at the operating position becomes a preset margin ε.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine (hereinafter referred to as an engine) provided with a supercharger for increasing the torque by compressing intake air by a compressor.

[0002]

2. Related Art As a turbocharger of this type, there is a turbocharger in which a turbine is rotated by using exhaust gas, and intake air is compressed by a coaxially provided compressor. 2. Description of the Related Art Variable-capacity turbochargers in which a vane provided on a turbine side is opened and closed to adjust the flow velocity of exhaust gas and thereby adjust the supercharging pressure have been put to practical use. In this variable capacity turbocharger, a target supercharging pressure is determined from a map based on, for example, an engine load and an engine rotation speed, and the vane opening is controlled so that the actual supercharging pressure becomes the target supercharging pressure. Thus, the supercharging pressure control according to the operating state of the engine is realized.

On the other hand, the characteristics of a turbocharger are represented by a compressor efficiency map. As is well known, the pressure ratio (pressure between upstream and downstream of the compressor) exceeds a surging line set on the efficiency map. If the ratio changes to a higher frequency side, so-called surging occurs in which the efficiency drops sharply due to partial backflow of the intake air. In a variable displacement turbocharger that controls the supercharging pressure (that is, the pressure at the outlet of the compressor), the pressure ratio changes according to the supercharging pressure control. The target supercharging pressure map is set so as not to exist.

However, the pressure ratio is affected not only by the supercharging pressure but also by the atmospheric pressure (that is, the pressure on the inlet side of the compressor). For example, at a high altitude where the atmospheric pressure is lower than that of a flat ground, the same supercharging pressure is achieved. The probability of crossing the surging line is increased because a higher pressure ratio is required to achieve this. Therefore, in order to prevent surging, the target supercharging pressure map is set on the premise that the atmospheric pressure is low, such as at high altitude, but in this case, the pressure ratio is suppressed more than necessary on a normal flat terrain. This causes a problem that the engine torque is reduced.

As a countermeasure for suppressing such surging, for example, a technique described in Japanese Utility Model Laid-Open No. 6-69331 can be mentioned. In this control device, the upstream side and the downstream side of the intake side of the variable displacement turbocharger are connected by a bypass passage, and a relief valve is provided in the bypass passage. Then, an upper limit value of the pressure ratio is set in the vicinity of the surging line in advance for each engine speed, and the actual pressure ratio calculated from the atmospheric pressure and the pressure of the intake manifold is:
When the upper limit value corresponding to the current engine rotation speed is exceeded, the above-mentioned relief valve is opened to return the compressed air on the downstream side to the upstream side, thereby reducing the pressure ratio to suppress surging.

[0006]

However, as is apparent from the above description, the technique disclosed in the above-mentioned publication is a fail-safe technique for suppressing surging when the pressure ratio rises abnormally for some reason. And
No consideration is given to actively increasing the pressure ratio to near the surging line. Therefore, there is a problem that the pressure ratio is suppressed on flat ground due to the influence of the atmospheric pressure change, and a sufficient engine torque cannot be obtained.

An object of the present invention is to always maintain the pressure ratio positively near the surging line without being affected by changes in the atmospheric pressure. As a result, it is possible to obtain a sufficient engine torque while preventing surging. An object of the present invention is to provide a control device for an internal combustion engine with a supercharger which can be provided.

[0008]

In order to achieve the above object, according to the present invention, a pressure ratio determining means for determining a pressure ratio between a compressor upstream and a downstream of a supercharger provided in an internal combustion engine. Operating parameter determining means for determining an operating parameter capable of determining a surging line of the supercharger and an operating position of the supercharger in association with the pressure ratio; pressure ratio determined by the pressure ratio determining means; Based on the operating parameters determined by the parameter determining means, the operating position determining means for determining the current operating position of the turbocharger with respect to the surging line, and the operating position and the surging line determined by the operating position determining means. Pressure ratio control means for controlling the pressure ratio of the supercharger to be close to the surging line within a range not exceeding the surging line.

Therefore, based on the pressure ratio determined by the pressure ratio determining means and the operating parameter determined by the operating parameter determining means, the current operating position of the turbocharger with respect to the surging line is determined by the operating position determining means. Then, based on the surging line and the operating position, the pressure ratio of the supercharger is controlled to be in the vicinity within a range not exceeding the surging line. Then, since the supercharger is controlled based on the pressure ratio as described above, when the atmospheric pressure changes according to a level ground, a highland, or the like, the supercharging pressure is increased or decreased while maintaining the same pressure ratio accordingly. That is, the pressure ratio is always maintained near the surging line without being affected by the change in the atmospheric pressure.
Therefore, at high altitude where the atmospheric pressure is low, surging due to an increase in the pressure ratio is prevented beforehand, and in flat ground where the atmospheric pressure is high, a sufficient engine torque is secured without unnecessarily suppressing the pressure ratio.

According to the second aspect of the present invention, the operating parameter determining means determines the air flow rate passing through the compressor of the turbocharger, and the operating position determining means performs surging based on the air flow rate and the pressure ratio. It is configured to determine the operation position with respect to the line. Therefore, the current operating position of the turbocharger with respect to the surging line is determined based on the pressure ratio determined by the pressure ratio determining means and the air flow rate determined by the operating parameter determining means.

Further, according to the present invention, the operating parameter determining means determines the rotational speed of the internal combustion engine, and the operating position determining means determines the operating position with respect to the surging line based on the engine rotational speed and the pressure ratio. Was determined. Therefore, the current operating position of the turbocharger with respect to the surging line is determined based on the pressure ratio determined by the pressure ratio determining means and the engine speed determined by the operating parameter determining means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of a control device for a supercharged internal combustion engine embodying the present invention will be described below. As shown in the overall configuration diagram of FIG. 1, an air cleaner 2, a compressor 3 a of a turbocharger 3, and an intercooler 4 are provided in an intake passage of the engine 1 from an upstream side, and intake air introduced through the air cleaner 2 is: After being guided in the intake passage and compressed by the compressor 3a, it is cooled by the intercooler 4, and further, fuel is injected from a fuel injection valve (not shown) and introduced into the combustion chamber of the engine 1 as an air-fuel mixture. In the exhaust passage of the engine 1, a turbine 3b of the turbocharger 3 is provided coaxially with the compressor 3a. Exhaust gas after combustion in the combustion chamber is guided to the exhaust passage to rotate the turbine 3b. After being discharged to the outside. The turbocharger 3 is configured as a so-called variable displacement type in which the flow rate of exhaust gas colliding with the turbine 3b can be adjusted by a number of vanes (not shown) provided around the turbine 3b.

In the passenger compartment, an input / output device (not shown), storage devices (ROM, RAM, BURAM, etc.) for storing control programs and control maps, and a central processing unit (C)
An ECU (engine control unit) 11 having a PU, a timer counter, and the like is provided. On the input side of the ECU 11, an air flow meter 12 as a hot wire type operation parameter determining means for detecting the intake air amount Ga as a weight flow rate, and a compressor 3a of the turbocharger 3
Temperature sensor 13 for detecting an inlet temperature Tin of the compressor, an inlet pressure sensor 14 for detecting an inlet pressure Pin of the compressor 3a,
Various sensors such as an outlet pressure sensor 15 for detecting the outlet pressure Pout of the compressor 3a are connected. E
An actuator 16 that drives the vanes of the turbocharger 3 to open and close is connected to the output side of the CU 11.
A fuel injection valve or a spark plug (not shown) provided in the engine 1 is connected.

The ECU 11 executes fuel injection control by a fuel injection valve or ignition timing control by a spark plug based on detection information from each sensor. Also, the ECU 11
Controls the supercharging pressure by opening and closing the vane of the turbocharger 3 by the actuator 16. Next, this ECU
The details of the control of the turbocharger 3 executed by 11 will be described.

The characteristics of the turbocharger 3 of the present embodiment are represented by a compressor efficiency map shown in FIG.
As is well known, in this map, the vertical axis represents the pressure ratio πc between the upstream side and the downstream side of the compressor, and the horizontal axis represents the compressor 3a.
The surging line S, which is the upper limit of the pressure ratio πc at which the turbocharger 3 can operate normally, is shown as the air flow rate Q (volume flow rate) passing through the turbine, together with the turbine rotation speed Nt and the compressor efficiency ηc. In the present embodiment, during full load operation, the vane is operated such that the turbocharger 3 is operated at a pressure ratio πc on a target control line Stgt (shown by a broken line) set slightly lower than the surging line S. Execute the opening control.

The ECU 11 executes a vane opening control routine shown in FIGS. 3 and 4 at predetermined control intervals. First, at step S2, the intake air amount Ga detected by the air flow meter 12 and the temperature sensor 13 detect the intake air amount Ga. Compressor inlet temperature Tin, compressor inlet pressure Pin detected by inlet pressure sensor 14 (converted to absolute value), compressor outlet pressure P detected by outlet pressure sensor 15
Read detection information such as out (converted to absolute value). Then
In step S4, the intake air amount Ga, which is a weight flow rate, is converted into a volume flow air flow rate Q according to the following equation (1).

Q = Ga / γ = Ga / (Pin / R / Tin) (1) where γ is a specific weight and R is a gas constant. Thereafter, in step S6, a current air flow rate Q0 at a reference temperature (for example, 25 ° C.) assumed by the map is calculated according to the following equation (2). Q0 = Q√ (Tin0 / Tin) (2) where Tin0 is the compressor inlet temperature Ti at the reference temperature.
n.

The above equation (2) was derived as follows. Since the air flow rate Q corresponds to the dimensionless quantity G√T / P of the compressible fluid, the relationship between the intake air quantity Ga and the air flow rate Q can be expressed by the following equation (3). G = γ · Q = (Pin / R · Tin) Q (3) Therefore, G√T / P is given by G√T / P = Q / √T / RＲQ / √T. 4) can be expressed. And if T is the reference temperature,
G√T / P〜Q.

Here, since Q / で あ T is a dimensionless equivalent amount, when each value at the reference temperature is represented by a suffix,
0 / √T0 = Q / √T, and the above equation is transformed into the above equation.
(2) can be derived. On the other hand, the ECU 11 determines in step S8 that the pressure ratio πc can be realized in the current operation state.
Set the surge limit pressure πcs which is the upper limit of. FIG. 5 is a partially enlarged explanatory view of the efficiency map of FIG. 2. As shown in FIG. 5, a plurality of different air flow rates Q (Q 1 to Q 3 are shown as representatives in the figure) on the surging line S in advance.
Corresponding to the surge limit pressure πcs (in the figure, πc1
To πc3) are set. In step S8,
According to the characteristics in this figure, the air flow rate Q and the surge limit pressure πcs
The surge limit pressure πcs is obtained from the air flow rate Q while performing the supplementary processing based on a map (not shown) defining the following.
Thereafter, in step S10, the current pressure ratio πc is calculated according to the following equation (5) (pressure ratio determining means).

Πc = Pout / Pin (5) In the following step S12, it is determined whether the operating condition is full load. This determination process is performed based on, for example, the accelerator pedal depression amount, and when the accelerator pedal depression amount is equal to or more than a predetermined value, it is considered that the load is full. If the determination in step S12 is NO (negative), the routine is terminated once after executing the vane opening control according to the operating conditions in step S14. In this case, the vane opening control is performed based on the engine rotation speed Ne and the like when EGR is not introduced, and when the EGR is introduced.
Set the target boost pressure or target burn opening from the GR amount, etc.
The vane opening is controlled to achieve the target boost pressure or the target vane opening.

If the determination in step S12 is YES (Yes), the process proceeds to step S16, and the difference Δ between the current surge limit pressure πcs and the pressure ratio πc is calculated according to the following equation (6).
πc is determined, and it is determined in step S18 whether or not the condition of the following equation (7) is satisfied, in other words, whether or not the current operating position is within the control range δ (position determining means). Δπc = πcs−πc (6) | Δπc−ε | <δ (7) Here, as shown in FIG. 5, ε corresponds to the difference between the surging line S and the target control line Stgt. The margin, δ, is a control range around the target control line Stgt. If the determination in step S18 is YES, that is, if the current operating position is within the control range δ, in order to prevent the target value from hunting near the target control line Stgt, the current vane is set in step S20. After maintaining the opening, the routine ends.

When the determination in step S18 is NO,
That is, if the current operating position is outside the control range δ, it is determined in step S22 whether the condition of the following equation (8) is satisfied, in other words, whether the current operating position is lower than the target control line Stgt. Is determined. Δπc−ε> 0 (8) If the determination in step S22 is YES, that is, if the current operating position is lower than the target control line Stgt, the flow shifts to step S24 to correct the correction amount according to the following equation (9). Find ΔPout.

ΔPout = (Δπc−ε) Pin (9) Thereafter, in step S26, a target supercharging pressure Pout (= compressor outlet pressure) is set according to the following equation (10), and in step S28, the vane is closed. After the control, the routine is terminated. Pout = Pout + ΔPout (10) When the determination in step S22 is NO, that is, when the current operating position is higher than the target control line Stgt, the process proceeds to step S30 and the correction amount is calculated according to the following equation (11). ΔPou
Find t.

.DELTA.Pout = (. Epsilon .-. DELTA..pi.c) Pin (11) Thereafter, in step S32, a target boost pressure Pout is set in accordance with the following equation (12). finish. Pout = Pout−ΔPout (12) Accordingly, the actual pressure ratio πc converges on the target control line Stgt, particularly within the range of Stgt ± δ by the above processing.

As described above, in the embodiment, the supercharging pressure control is performed based on the pressure ratio πc. Therefore, if the compressor inlet pressure Pin changes together with the atmospheric pressure in accordance with the level ground, highland, etc., the same pressure is applied. The supercharging pressure is increased or decreased while maintaining the pressure ratio πc (as described above, a value lower by the margin ε than the surge limit pressure ratio πcs). Therefore,
The pressure ratio πc is always held at the target control line Stgt without being affected by the atmospheric pressure change, and in a high altitude where the atmospheric pressure is low, surging due to an increase in the pressure ratio is prevented beforehand, and in a flat ground where the atmospheric pressure is high, Sufficient engine torque is secured without unnecessarily suppressing the pressure ratio.

That is, the compressed air flowing downstream of the compressor is returned to the upstream side through the bypass passage.
As in the technique of 69331, not only the abnormal increase of the pressure ratio πc can be prevented, but also the pressure ratio πc can be positively increased to just before the surging line S.
Sufficient engine torque can be secured while preventing surging, and the characteristics of the variable displacement turbocharger capable of arbitrarily controlling the supercharging pressure can be maximized.

Further, the supercharging pressure is affected not only by a change in the atmospheric pressure but also by a change in the outside air temperature. For example, when the outside air temperature becomes low, the air density becomes high. The possibility of increasing and exceeding the surging line S increases. In the present embodiment, as is apparent from the above equations (1) and (2), the compressor inlet temperature Tin (that is, the outside air temperature) is taken into account when calculating the air flow rate Q, which is the volume flow rate. There is also an advantage that the influence of the temperature change can be eliminated, and the pressure ratio πc can be always maintained immediately before the surging line S regardless of the outside air temperature.

On the other hand, the configuration of the turbocharger 3 itself is already existing including the actuator 16 for opening the vane, and only changes the content of the supercharging pressure control from the conventional general one. The various effects described above can be obtained without complicating the configuration as compared with the technique disclosed in Japanese Utility Model Laid-Open No. 6-69331, which requires a bypass passage and a relief valve.

[Second Embodiment] A second embodiment of a control device for a supercharged internal combustion engine embodying the present invention will be described below. The control device of the present embodiment has the same basic configuration as that of the control device of the first embodiment, the air flow meter 12 for detecting the intake air amount Ga is omitted, and the intake air amount Ga (weight flow rate) is calculated. ) Is different. Therefore, this difference will be mainly described.

FIG. 6 shows a vane opening control routine executed by the ECU 11 of the second embodiment. In this figure, different points from the routine of the first embodiment shown in FIGS. 3 and 4 are shown. After reading the detection information in step S2 as in the first embodiment, the ECU 11 first calculates the volume efficiency ηv according to the following equation (13) in step S102.

Ηv = ηv0 · (Tmani / Tmani0) ^m (13) Here, Tmani is the temperature at the intake manifold portion (hereinafter, referred to as the intake manifold temperature), Tmani0 is the reference intake manifold temperature, ηv0 is the reference volumetric efficiency, m is the intake manifold temperature Tmani
Is a volume efficiency index that represents a change in volume efficiency ηv due to the influence of. That is, since the volumetric efficiency ηv is affected by not only the engine speed Ne and the engine load but also the intake manifold temperature Tmani as shown in FIG. 7, it is necessary to consider the intake manifold temperature Tmani when obtaining the volumetric efficiency ηv. The volume efficiency ηv at an arbitrary intake manifold temperature Tmani can be defined by the above equation (13) regardless of the fuel injection timing and the vane opening of the turbocharger 3.

In the following step S104, the ECU 11 calculates
The intake air amount Ga (weight flow rate) is calculated according to (14).

[0033]

(Equation 1)

Where Vh is the stroke volume of the engine 1 and γm
ani is a specific weight of the intake air at the intake manifold portion (hereinafter, referred to as an intake manifold specific weight). In addition, the above formula (1
4) was derived as follows. First, the above volume efficiency ηv can be defined by the following equation (15).

[0035]

(Equation 2)

Here, Pa is the atmospheric pressure, and Pmani is the pressure at the intake manifold (detected as a gauge pressure, hereinafter referred to as the intake manifold pressure). The intake manifold specific weight γmani can be defined by the following equation (16).

[0037]

(Equation 3)

Therefore, when equation (15) is transformed, the above equation (14) is obtained.
Can be derived. Equation (16) represents the intake manifold pressure P
Although the case where mani is detected as a gauge pressure is shown, when the intake manifold pressure Pmani is an absolute pressure, the term of the atmospheric pressure Pa becomes unnecessary. After that, it is the same as the first embodiment, and the air flow rate Q at the reference temperature and the pressure ratio πc
, The current operating position on the map is determined, and the setting process of the target supercharging pressure Pout is executed according to FIG. 5 to be reflected in the supercharging pressure control.

Therefore, similarly to the first embodiment, the pressure ratio πc can be positively increased up to just before the surging line S without being affected by the change in the atmospheric pressure. Can be secured. Furthermore, since the intake manifold pressure Pmani, intake manifold temperature Tmani, and atmospheric pressure Pa used for calculating the intake air amount Ga are used in fuel injection control or ignition timing control on the engine side, these detection information is obtained from existing sensors. Obtained and there is no need to add new sensors. Since the intake air amount Ga is obtained by the arithmetic processing in this manner, when a fuel injection system that does not require the intake air amount Ga as a control parameter for fuel injection, such as D JETRONIC, is used, By omitting the air flow meter 12, the configuration of the entire control device can be simplified, which can contribute to a reduction in manufacturing cost.

[Third Embodiment] Hereinafter, a third embodiment of a control device for an internal combustion engine with a supercharger embodying the present invention will be described. The control device of the present embodiment has the same basic configuration as those of the first and second embodiments, and the inlet pressure sensor 14 and the outlet pressure sensor 15 are omitted, and the suction device is inhaled as in the second embodiment. The difference is that not only the air amount Ga but also the compressor inlet pressure Pin and the compressor outlet pressure Pout are calculated by a calculation process. Therefore, this difference will be mainly described.

FIG. 8 shows a vane opening control routine executed by the ECU 11 of the third embodiment, and FIG. 8 shows different points from the routine of the second embodiment of FIG. The ECU 11 performs step S as in the second embodiment.
2, the detection information is read, and in step S102, the volumetric efficiency η
After calculating v and calculating the intake air amount Ga in step S104, first, in step S202, the compressor inlet pressure Pin is calculated.

The process for calculating the compressor inlet pressure Pin is performed in the following procedure. As shown in the overall configuration diagram of FIG.
The compressor inlet pressure Pin is controlled by the compressor 3a of the turbocharger 3 from the air cleaner 2 with respect to the atmospheric pressure Pa.
Since the pressure loss ΔPac can be regarded as a value obtained by subtracting
The pressure loss ΔPac is calculated according to the following equation (17). The intake air amount Ga is calculated from the above equation (14) as in the second embodiment.

[0043]

(Equation 4)

Here, Kac is a constant determined in the present intake system (corresponding to the slope of the characteristic in FIG. 10), γac is the specific weight of the intake air in the air cleaner 2, and the specific weight γac is given by the following equation (18). Can be calculated.

[0045]

(Equation 5)

Here, Ta is the atmospheric temperature. Using the pressure loss ΔPac thus obtained, the compressor inlet pressure Pin is calculated according to the following equation (19). Pin = Pa−ΔPac (19) In the following step S204, the compressor outlet pressure Pout is similarly calculated in the following procedure. Since the compressor outlet pressure Pout can be regarded as a value obtained by adding the pressure loss ΔPic in the intercooler 4 to the intake manifold pressure Pmani, first, the pressure loss ΔPic is calculated according to the following equation (20).

[0047]

(Equation 6)

Here, Kic is a constant (corresponding to the slope of the characteristic in FIG. 11) determined in the main intake system. Note that the intake manifold specific weight γmani is determined by the above equation (16). Using the pressure loss ΔPic thus obtained, the compressor outlet pressure Pout is calculated according to the following equation (21). Pout = Pmani + ΔPic (21) The above equations (17) and (20) were derived as follows. The pressure loss ΔP can be represented by the well-known pressure loss equation (22). That is,

[0049]

(Equation 7)

Where ξ is the pressure loss coefficient, V is the flow velocity in the pipe, g
Is the gravitational acceleration. Assuming that the pipe cross-sectional area is A, the pipe flow velocity V is

[0051]

(Equation 8)

When the pipeline system is determined, since the pressure loss coefficient ξ, the gravitational acceleration g, and the pipeline cross-sectional area A are constant values, when equation (23) is substituted into equation (22),

[0053]

(Equation 9)

Thus, the above equations (17) and (20) hold.
Note that the relationship of equation (17) is expressed as the characteristic of FIG.
Is expressed as a characteristic shown in FIG. After that
As in the first and second embodiments, the current operating position on the map is determined based on the air flow rate Q at the reference temperature and the pressure ratio πc obtained from the above values, and the target supercharging is performed according to FIG. The setting process of the pressure Pout is executed and reflected in the supercharging pressure control.

Therefore, similarly to the first and second embodiments,
The pressure ratio πc can be positively increased to just before the surging line S without being affected by changes in the atmospheric pressure, and sufficient engine torque can be secured while preventing surging. Further, an intake manifold pressure Pmani, an intake manifold temperature Tmani, an atmospheric pressure Pa, and an atmospheric temperature Ta applied to the calculation of the compressor inlet pressure Pin and the compressor outlet pressure Pout.
Is used in fuel injection control or ignition timing control on the engine side, such detection information is obtained from existing sensors, and there is no need to add new sensors. And
As described above, since the compressor inlet pressure Pin and the compressor outlet pressure Pout are obtained by the arithmetic processing, the inlet pressure sensor 14 and the outlet pressure sensor 15 are further omitted from the configuration of the second embodiment to simplify the configuration of the entire control device. This can contribute to a reduction in manufacturing cost.

[Fourth Embodiment] Hereinafter, a fourth embodiment of a control device for an internal combustion engine with a supercharger according to the present invention will be described. The control device of the present embodiment has the same basic configuration as that of the control device of the first embodiment, and differs from the control device of the first embodiment in the process of setting the target supercharging pressure Pout. Therefore, this difference will be mainly described.

FIG. 12 shows a vane opening control routine executed by the ECU 11 of the fourth embodiment.
FIG. 5 shows different points from the routine of the first embodiment shown in FIGS. 3 and 4. After reading the detection information in step S2 as in the first embodiment, the ECU 11 first reads the pressure ratio π that can be realized in the current operation state in step S302.
Set the surge limit pressure πcs, which is the upper limit of c.

As shown in FIG. 13, in this embodiment, instead of the air flow rate Q, the surge limit pressure πcs corresponding to the engine rotation speed Ne (Ne1 to Ne3 is shown in the figure as a representative).
(In the figure, πc1 to πc3 are shown as representatives) are set in advance. In step S302, based on a map (not shown) defining the engine speed Ne and the surge limit pressure πcs according to this figure, the surge limit pressure πcs is obtained from the engine speed Ne while performing a supplementary process. The engine rotation speed Ne at this time is detected by an engine rotation speed sensor 21 (shown in FIG. 1) as operating parameter determination means.

After that, as in the first embodiment, the current operating position on the map is determined based on the air flow rate Q at the reference temperature and the pressure ratio πc obtained from the above values, and FIG.
The setting process of the target supercharging pressure Pout is executed according to No. 3 and reflected in the supercharging pressure control. Therefore, as in the first embodiment,
The actual pressure ratio πc is a margin ε from the surge limit pressure ratio πcs.
And converges on the target control line Stgt, which is lower than the target control line Stgt. Since the supercharging pressure control is performed based on the pressure ratio πc in this manner, the pressure ratio πc is not affected by a change in the atmospheric pressure. It is possible to positively increase the level immediately before, and it is possible to secure a sufficient engine torque while preventing surging.

The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, in the above-described embodiment, the control device for the turbocharger 3 that is driven to rotate by using the exhaust gas is embodied. In short, the upper limit of the pressure ratio is determined by the surging line S as shown in FIG. As long as the centrifugal supercharger has characteristics, the type of the supercharger is not limited to this.
Therefore, for example, a control device for a supercharger of a type in which the compressor 3a is rotationally driven by using the driving force of the engine 1 may be embodied. Regarding the supercharging pressure control type, instead of opening and closing a large number of vanes as in the embodiment, the supercharging pressure is controlled by adjusting the opening area of the turbine inlet with a single flap, or May be used to adjust the supercharging pressure.

In the above embodiment, the intake air flow rate Ga is detected as a weight flow rate by the hot wire air flow meter 12 and the intake air flow rate Ga is converted into an air flow rate Q which is a volume flow rate. Is not limited to this, and the intake air amount Ga may be directly detected as a volume flow rate using, for example, a Karman vortex sensor.

[0062]

As described above, according to the control apparatus for an internal combustion engine with a supercharger of the present invention, since the supercharger is controlled based on the pressure ratio, it is not affected by changes in the atmospheric pressure. Therefore, the pressure ratio can be positively maintained near the surging line, and as a result, sufficient engine torque can be secured while preventing surging.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a control device for an internal combustion engine with a supercharger according to a first embodiment.

FIG. 2 is an explanatory diagram showing an efficiency map of a compressor.

FIG. 3 is a flowchart showing a vane opening control routine executed by an ECU.

FIG. 4 is a flowchart illustrating a vane opening control routine executed by an ECU.

FIG. 5 is an explanatory diagram showing a procedure for setting a target supercharging pressure Pout.

FIG. 6 is a flowchart illustrating a vane opening control routine executed by an ECU according to a second embodiment.

FIG. 7 is an explanatory diagram showing a correlation between a volume efficiency ηv and an intake manifold temperature Tmani.

FIG. 8 is a flowchart illustrating a vane opening control routine executed by an ECU according to a third embodiment.

FIG. 9 is an overall configuration diagram illustrating a control device for an internal combustion engine with a supercharger according to a third embodiment.

FIG. 10 is an explanatory diagram showing characteristics of a pressure loss ΔPac.

FIG. 11 is an explanatory diagram showing characteristics of a pressure loss ΔPic.

FIG. 12 is a flowchart illustrating a vane opening control routine executed by an ECU according to a fourth embodiment.

FIG. 13 is an explanatory diagram showing a procedure for setting a target supercharging pressure Pout.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine (internal combustion engine) 3 Turbocharger (supercharger) 3a Compressor 11 ECU (pressure ratio determination means, operating position determination means,
Pressure ratio control means) 12 air flow meter (operation parameter judgment means) 21 engine rotation speed sensor (operation parameter judgment means) S surging line πc pressure ratio

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G005 EA04 EA16 GA04 GE01 GE09 JA13 JA23 JA24 JA39 JA45 JB02 JB04 JB05 3G092 AA01 AA05 AA18 DB03 EA01 EA02 EC01 EC09 FA02 HA01Z HA04Z HA05Z HA11Z HF08Z HG07Z HG08Z

Claims (3)

[Claims] 1. A pressure ratio determining means for determining a pressure ratio between an upstream side and a downstream side of a compressor of a supercharger provided in an internal combustion engine, and a surging line of the supercharger and a supercharger associated with the pressure ratio. Operating parameter determining means for determining an operating parameter capable of determining the operating position of the feeder; a pressure ratio determined by the pressure ratio determining means; and an operating parameter determined by the operating parameter determining means. Operating position determining means for determining the current operating position of the turbocharger with respect to the surging line; and, based on the operating position determined by the operating position determining means and the surging line, a range not exceeding the surging line. A control device for an internal combustion engine with a supercharger, comprising: a pressure ratio control means for controlling a pressure ratio of the supercharger near a surging line. 2. The operating parameter determining means determines an air flow rate passing through a compressor of the supercharger, and the operating position determining means determines an operating position with respect to a surging line based on the air flow rate and the pressure ratio. 2. The control device for an internal combustion engine with a supercharger according to claim 1, wherein: 3. The operating parameter determining means determines a rotational speed of the internal combustion engine, and the operating position determining means includes:
The control device for an internal combustion engine with a supercharger according to claim 1, wherein an operation position with respect to a surging line is determined based on the engine rotation speed and the pressure ratio.