JP2920220B2 - Supercharging pressure control device for internal combustion engine with supercharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging pressure control device for a supercharged internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as a supercharging pressure control device for a supercharged internal combustion engine, a supercharger as a rotary pump is arranged in an engine intake system, and the supercharger is connected to an engine rotating shaft. In a bypass control device for a supercharger of an internal combustion engine, a bypass passage is provided so as to bypass the engine, and a bypass control unit opens and closes the bypass passage according to an engine operating state. There is a known type that includes a detecting unit for detecting, and a bypass closing unit that drives a bypass control unit so that the bypass passage is fully closed when the low temperature of the engine is detected by the detecting unit (for example, Japanese Utility Model Laid-Open No. 61-17141). In this prior art, when the low temperature of the engine is detected by the detecting means at the time of starting the engine, the bypass passage is fully closed and supercharging is maximized, thereby promoting warm-up.

[0003]

However, in the above prior art, when the low temperature of the engine is detected by the detecting means at the time of starting the engine, the bypass passage is fully closed and the supercharging is performed to the maximum. Wastefully consumes more fuel and deteriorates fuel efficiency, and the catalytic converter disposed in the exhaust system has a low purification rate (reaction rate) until the inflowing exhaust gas temperature reaches a predetermined temperature. There is a problem that a large amount of exhaust gas is exhausted without being purified at the time of supply, and exhaust gas performance (E / M performance) deteriorates.

The present invention has been made in view of such conventional problems, and it is possible to increase the purification rate of a catalytic converter at an early stage without deteriorating fuel consumption during no-load operation. It is an object of the present invention to provide a supercharging pressure control device for a supercharged internal combustion engine with improved exhaust gas performance.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a supercharger disposed in an intake passage of an internal combustion engine, a supercharging pressure adjusting valve for adjusting a supercharging pressure, and a supercharging pressure adjusting valve. In a supercharging pressure control device for a supercharged internal combustion engine comprising a driving device for driving and a control device for controlling the device, a catalyst converter provided in an exhaust system of the internal combustion engine, and a temperature of the catalyst converter A temperature sensor for detecting, when the temperature of the catalytic converter detected by the temperature sensor during a no-load operation is lower than a predetermined temperature, the supercharging pressure in the intake passage increases the temperature of the catalytic converter. The opening degree of the supercharging pressure regulating valve is controlled so that the target supercharging pressure according to the above-mentioned condition is obtained.

[0006]

In the above-mentioned supercharging pressure control device, when the temperature of the catalytic converter detected by the temperature sensor is lower than a predetermined temperature during the no-load operation, the supercharging pressure is adjusted to the target supercharging pressure corresponding to the temperature of the catalytic converter. In order to control the opening of the supercharging pressure regulating valve so as to achieve the supply pressure, supercharging is performed according to the temperature of the catalytic converter, and the exhaust gas temperature rises.

[0007]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a supercharging pressure control device for a supercharged internal combustion engine according to an embodiment of the present invention. As shown in FIG. 1, the supercharging pressure control device includes a supercharger 3 disposed in an intake passage 2 of an internal combustion engine 1, a bypass passage 4 bypassing the supercharger 3, and opening and closing of the bypass passage 4. Pressure adjusting valve 5 to be controlled, a step motor (driving means) 6 for driving the adjusting valve 5, and an EC for controlling the step motor 6 and the like.
A U (control device) 7 is provided. The rotation of the crankshaft 1a of the internal combustion engine 1 is controlled by the pulley 8, the belt 9, and the pulley 1
0 is always transmitted to the rotating shaft 3a of the supercharger 3.

An air cleaner 1 is provided at an upstream end of the intake passage 2.
1 is provided. At the downstream end of the intake passage 2,
An intake manifold 12 that guides intake air to intake ports of each cylinder of the internal combustion engine 1 is provided. The supercharger 3
Is disposed upstream of the throttle valve 13. In the intake passage 2 between the supercharger 3 and the throttle valve 13, a water-cooled intercooler 14 for cooling the intake air pressurized by the supercharger 3 is arranged. The water-cooled intercooler 14
The cooling water circulating through the radiator 15 and the pipe 16 is pumped by the water pump 17.

Exhaust gas exhausted from the exhaust port of each cylinder of the internal combustion engine 1 is guided by an exhaust manifold 30 and merges. A catalytic converter 32 is provided in an exhaust pipe 31 connected to the junction.

[0011] The ECU7 the engine speed NE detected by the NE sensor (not shown), downstream of the boost pressure PB of the throttle valve 13 detected by the PB sensor 18, the throttle detected by the P ₂ sensor 19 Supercharging pressure P upstream of valve 13
_2. Throttle opening θTH of throttle valve 13, intercooler water temperature TWIC detected by water temperature sensor 20, CAT
Signals representing the temperature TCAT of the catalytic converter 32 detected by the temperature sensor (temperature sensor) 21 and the vehicle speed v detected by a vehicle speed sensor (not shown) are input. The temperature TCAT of the catalytic converter 32 used in this specification
(Hereinafter, simply referred to as CAT temperature TCAT) is the temperature of the exhaust gas flowing into the inlet of the catalytic converter 32 or the temperature of the catalyst bed in the catalytic converter 32.

The ECU 7 controls the throttle valve 1
3 of the upstream side or downstream side supercharging pressure P ₂ or PB (hereinafter, simply referred to as the boost pressure PB) when reaches the maximum supercharging pressure POBJ, the open control, the boost pressure PB is the maximum supercharging pressure POBJ To the feedback control for controlling the opening of the supercharging pressure adjusting valve 5 so that the actual opening degree of the supercharging pressure adjusting valve 5 during the feedback control (hereinafter referred to as the actual opening smoothing value). ΘREF is the target opening θOBJ according to the operating state at that time.
When the value becomes smaller, the feedback control is shifted to the open control for controlling the opening of the supercharging pressure regulating valve 5 to the target opening θOBJ.

Further, the ECU 7 controls the C
When the CAT temperature TCAT detected by the AT temperature sensor 21 is lower than a predetermined temperature (for example, 250 ° C.), the supercharging pressure P
The opening degree of the boost pressure regulating valve 5 is feedback-controlled so that B becomes the target boost pressure PMAP corresponding to the CAT temperature TCAT.

Next, the operation of the supercharging pressure control device for a supercharged internal combustion engine according to one embodiment having the above-described configuration will be described.

First, the ECU 7 executes a TDC process shown in FIG. This TDC process calculates the supercharging pressure P ₂ based on the signal representative of the upstream side of the supercharging pressure P ₂ of the throttle valve 13 detected by the P ₂ sensor 19 (step 30
1) Next, the throttle valve 1 detected by the PB sensor 18
3 based on the signal representing the supercharging pressure PB on the downstream side.
Is calculated (step 302), and the engine speed NE is calculated based on a signal representing the engine speed NE detected by an NE sensor (not shown) (step 303), and the process is terminated. Such TDC processing is repeatedly executed in synchronization with engine rotation. The calculated latest supercharging pressure P ₂ , supercharging pressure PB and engine speed NE are calculated for each TDC.
It is rewritten and stored in a memory (not shown) in the ECU 7 for each process.

After executing the TDC process, the ECU 7 executes a main routine shown in FIG. In this main routine, first, the supercharging pressures P ₂ , PB and the engine speed NE calculated and stored in the TDC process are read, and the throttle opening θTH of the throttle valve 13 and the CAT temperature sensor 21 detect the throttle opening θTH. Calculated based on signals representing the CAT temperature TCAT and the vehicle speed v, respectively.
.Theta.TH, TCAT, and v which are rewritten and stored in the internal memory are read (step 201). Next, it is determined whether the vehicle speed v is equal to or lower than a predetermined value V (step 202). When this answer is affirmative (Yes), that is, when the vehicle speed v is equal to or less than the predetermined value V, it is determined whether the engine speed Ne is equal to or less than the predetermined value ne.
If the answer in step 203 is affirmative (Yes), that is, if Ne is n
When the value is equal to or less than e, that is, during the no-load operation, the routine proceeds to step 204, where it is determined whether the CAT temperature TCAT is equal to or higher than a predetermined temperature (250 ° C.).

If the answer to step 204 is negative (No), that is, if the CAT temperature TCAT is lower than a predetermined temperature (250 ° C.),
The target boost pressure PMAP corresponding to TCAT is determined (step 20).
5) Go to step 206. In this case, in step 206, the opening degree of the boost pressure regulating valve 5 is feedback-controlled so that the boost pressure PB becomes the target boost pressure PMAP.
After the execution of step 206, the main routine ends.

When the answer to step 202 is negative (No), that is, when the vehicle speed v is greater than the predetermined value V (when the vehicle is not running under no load), when the answer to step 203 is negative (No), that is, when Ne is greater than ne. (When not in no-load operation) or when the answer to step 204 is affirmative (Yes), that is, when the CAT temperature TCAT is at the predetermined temperature (250
° C) or more, the routine proceeds to step 207, where the target opening degree θOBJ of the boost control valve 5 for open control is calculated. Next, the routine proceeds to step 208, where the maximum boost pressure POBJ for feedback control is calculated, and further, to step 209, one of the control modes of the open control and the feedback control is determined. Next, it is determined whether the control mode determined in step 209 is feedback control (step 210). When the answer to step 210 is affirmative (Yes), the routine proceeds to step 206, where feedback control is performed. In this case, this step 20
In step 6, the opening degree of the supercharging pressure regulating valve 5 is feedback-controlled so that the supercharging pressure PB read in step 201 becomes the maximum supercharging pressure POBJ calculated in step 208.
On the other hand, when the answer to step 210 is negative (No),
Proceeding to step 211, open control is performed. In this open control, the opening of the supercharging pressure regulating valve 5 is controlled to the target opening θOBJ calculated in step 207. Such a main routine is repeatedly executed at regular intervals.

In step 205, the target supercharging pressure PMAP is stored in a memory in the ECU 7 by tabulating the optimum target supercharging pressure PMAP determined by the CAT temperature TCAT as shown in FIG. Is calculated by searching the table of. That is, the target boost pressure P
MAP is the latest CA read in step 201.
It is calculated by searching a table of the target boost pressure PMAP shown in FIG. 4 based on the T temperature TCAT.

In step 207, the target opening degree θOBJ of the supercharging pressure regulating valve 5 is tabulated from the optimum target opening degree θOBJ determined by the engine speed NE and the throttle opening degree θTH as shown in FIG. It is calculated by searching a table of the target opening degree θOBJ stored in the memory inside.

In step 208, the maximum boost pressure POBJ for feedback control is calculated by executing a subroutine for determining the maximum boost pressure shown in FIG. In this subroutine, the latest engine speed NE is read again (step 701), and based on a signal representing the intercooler water temperature TWIC detected by the water temperature sensor 20, the latest engine speed calculated and stored in a background process (not shown) is stored. Is read (step 702). Next, the routine proceeds to step 703, where the engine speed N read in step 701 is read.
Based on E, as shown in FIG. 8, an optimal first maximum supercharging pressure PLMT determined by the engine rotational speed NE is mapped and stored in a memory in the ECU 7.
The PLMT is calculated by searching the table of T. Next, based on the intercooler water temperature TWIC read in step 702, the optimum second maximum supercharging pressure PIC determined by the intercooler water temperature TWIC is tabulated as shown in FIG. The PIC is calculated by searching a table of the second maximum boost pressure PIC. Further, the routine proceeds to step 705, where it is determined whether the first maximum boost pressure PLMT is equal to or lower than the second maximum boost pressure PIC. The answer is affirmative (Yes),
That is, when PLMT is less than PIC, the first maximum boost pressure PL
MT is determined as the maximum boost pressure POBJ (step 70).
6), and proceed to step 209 shown in FIG. On the other hand, when the answer to step 705 is negative (No), that is, when PIC is smaller than PLMT, the second maximum charging pressure PIC is set to the maximum charging pressure POB.
J is determined (step 707), and the process proceeds to step 209.

In step 209, the control mode is determined by executing a control mode determination subroutine shown in FIG.

In this subroutine, first, the actual opening smoothed value θREF of the supercharging pressure regulating valve 5 during the feedback control is determined (step 501). The θREF is calculated by executing a θREF calculation subroutine shown in FIG.
In the θREF calculation subroutine, first, the actual opening degree θBP is calculated from the number of pulses output from the ECU 7 to the step motor 6 (step 101). Next, ΔPB (ΔP
It is determined whether or not the sign of B = maximum supercharging pressure POBJ-supercharging pressure PB) has been reversed (step 102). When the sign of ΔPB is reversed, the routine proceeds to step 103, where the actual opening smoothing value θREF of the supercharging pressure regulating valve 5 during feedback is the current value θREF
Calculate n. On the other hand, when the sign of ΔPB is not inverted, the processing is terminated without performing the calculation in step 103.

After the actual opening smoothing value θREF of the supercharging pressure regulating valve 5 during the feedback control is determined in the subroutine of FIG. 10 in this manner, the process returns to the subroutine of FIG. It is determined whether or not the process is under feedback control, that is, whether or not the control mode determination flag F-FB is 1. If the answer to this step 502 is negative (No),
That is, when the open control is being performed, the routine proceeds to step 503, where it is determined whether the supercharging pressure PB is equal to or higher than the maximum supercharging pressure POBJ.
When the answer to this step 503 is affirmative (Yes), that is, when PB becomes equal to or larger than POBJ during the open control, the control mode determination flag F-FB is set to 1 indicating that the feedback control has been determined (step 504). ), And ends the subroutine of FIG. 5 to return to the main routine of FIG. In this case, the determination result of step 210 in FIG. 2 is affirmative (Yes), and the control shifts from open control to feedback control in step 206. On the other hand, if the answer to step 503 is negative (No),
When B is smaller than POBJ, the flag F-FB is set to 0 indicating that the open control has been determined (step 505), and the subroutine of FIG. 5 is ended to return to the main routine of FIG. In this case, step 21 in FIG.
The result of the determination in step 21 is negative (No).
At 1, the open control is continued.

On the other hand, if the answer to step 502 is affirmative (Y
es), that is, when the flag F-FB is 1 and the previous process is under feedback control, the routine proceeds to step 506, where it is determined whether the supercharging pressure PB is equal to or less than the maximum supercharging pressure POBJ-ΔPG. Here, ΔPG is set to provide hysteresis for preventing hunting. The answer to step 506 is affirmative (Yes), that is, PB is POBJ-ΔPG.
In the following cases, the process proceeds to step 505, where the flag F
-FB is set to 0 indicating that the open control has been determined, the subroutine of FIG. 5 is terminated, and the process returns to the main routine of FIG. In this case, the result of the determination in step 210 in FIG. 2 is negative (No), and in step 211, the control shifts from feedback control to open control.

If the answer to step 506 is negative (No),
That is, when PB is larger than POBJ-ΔPG, step 50 is executed.
Proceeding to 7, it is determined whether or not the θREF (θREFn) is equal to or larger than the target opening θOBJ. If the answer to this step 507 is negative (N
o), that is, when the actual opening smoothing value θREF of the supercharging pressure regulating valve 5 during feedback is smaller than the target opening θOBJ, the current operating state, ie, the engine speed NE and the throttle opening θTH
Thus, the supercharging pressure PB is in a state of being lowered, and if the feedback control is continued as it is, it is determined that the supercharging pressure PB is further increased, and the routine proceeds to step 505. In this case as well, the process proceeds to step 211 to shift from feedback control to open control.

On the other hand, when the answer to the step 507 is affirmative (Yes), that is, when the actual opening smoothed value θREF is equal to or larger than θOBJ, the current operating state, ie, the engine speed NE and the throttle opening θTH are considered. It is in a state where the supercharging pressure PB is increased, and it is determined that the feedback control should be continued as it is, and the process proceeds to step 508 to determine whether θTH is equal to or more than θFB. Here, θFB is a reference throttle opening that changes in relation to the engine speed NE. As shown in FIG. 11, the optimal reference throttle opening θFB determined by the engine speed NE is tabulated and stored in the memory in the ECU 7. Is stored in If the answer to step 508 is negative (No),
That is, when θTH changes suddenly and becomes smaller than θFB, the routine proceeds to step 505. Also in this case, step 211
To shift from feedback control to open control.

If the answer in step 508 is affirmative (Ye
s), that is, when θTH is equal to or larger than θFB, the aforementioned step 504 is executed.
Then, the control mode determination flag F-FB is set to 1 indicating that the feedback control has been determined, the subroutine of FIG. 5 is terminated, and the process returns to the main routine of FIG.
In this case, the determination result of step 210 in FIG. 2 becomes affirmative (Yes), and the process proceeds to step 206 to continue the feedback control.

As described above, in the supercharging pressure control device for the internal combustion engine with a supercharger according to the above-described embodiment, when the vehicle is not under no-load operation (when the vehicle speed v is equal to or less than the predetermined value V or v is V and the engine speed Ne is greater than a predetermined value ne), and during no-load operation (v is less than V and N
When e is equal to or less than ne) and the CAT temperature TCAT is equal to or higher than a predetermined temperature (250 ° C.), as shown in FIG. 12, feedback control is performed in a region where the supercharging pressure PB is equal to or higher than the maximum supercharging pressure POBJ. Open control is performed in a region where the supercharging pressure PB is smaller than the maximum supercharging pressure POBJ. By such control, the supercharging pressure P
B control speed and accuracy are improved. In addition, in the feedback control, the opening of the supercharging pressure adjusting valve 5 is controlled so that the supercharging pressure PB becomes the maximum supercharging pressure POBJ.
Is prevented from becoming abnormally high.

In the supercharging pressure control device for an internal combustion engine with a supercharger according to the above-described embodiment, the CA during the no-load operation is controlled.
When the T temperature TCAT is lower than a predetermined temperature (250 ° C.), CA
The target boost pressure PMAP corresponding to the T temperature TCAT is determined, and the boost pressure P is determined.
The opening degree of the boost pressure regulating valve 5 is feedback-controlled so that B becomes the target boost pressure PMAP. As a result, supercharging is performed in accordance with the CAT temperature TCAT, and the exhaust gas temperature rises. Therefore, the purification rate (reaction rate) of the catalytic converter 32 can be quickly increased without deteriorating fuel efficiency. As a result, purification of exhaust gas during traveling is improved, and exhaust gas performance (E / M performance) is improved.

In the embodiment, the internal combustion engine 1
As the supercharger 3 arranged in the intake passage 2 of the first embodiment, a mechanical supercharger (a so-called supercharger) driven by the internal combustion engine 1 is used, and as the supercharging pressure adjusting valve 5 for adjusting the supercharging pressure, A supercharging pressure control device for a supercharged internal combustion engine that controls a supercharging pressure by using a valve that opens and closes a bypass passage 4 that bypasses a supercharger 3 and controls an opening degree of the supercharging pressure adjusting valve 5. Was explained. However, the present invention is not limited to this. As a supercharger disposed in an intake passage of an internal combustion engine, a compressor (a so-called turbocharger) driven by an exhaust turbine rotating by the energy of exhaust gas is used.
A supercharged pressure is controlled by controlling the opening degree of the wastegate valve by using a wastegate valve that controls the amount of exhaust gas to the exhaust turbine as a supercharge pressure adjusting valve that adjusts the supercharge pressure. Pressure control device for an internal combustion engine with a supercharger.

[0032]

As described above, according to the present invention,
When the temperature of the catalytic converter detected by the temperature sensor during the no-load operation is lower than a predetermined temperature, the control device adjusts the supercharging pressure so that the supercharging pressure becomes a target supercharging pressure corresponding to the temperature of the catalytic converter. Since the opening degree of the valve is controlled, supercharging is performed according to the temperature of the catalytic converter, and the exhaust gas temperature rises. Therefore, during the no-load operation, the purification rate of the catalytic converter can be quickly increased without deteriorating the fuel efficiency,
Thereby, the exhaust gas performance can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a supercharging pressure control device for a supercharged internal combustion engine according to one embodiment of the present invention.

FIG. 2 is a flowchart showing a main routine of the supercharging pressure control device shown in FIG.

FIG. 3 is a flowchart illustrating TDC processing.

FIG. 4 is a map showing a temperature of a catalytic converter.

FIG. 5 is a flowchart showing a subroutine for determining a control mode.

FIG. 6 is a map showing a target opening for open control.

FIG. 7 is a flowchart showing a subroutine for determining a maximum supercharging pressure.

FIG. 8 is a map showing a first maximum boost pressure determined by an engine speed.

FIG. 9 is a map showing a second maximum supercharging pressure determined by an intercooler water temperature.

FIG. 10 is a subroutine for calculating an actual opening degree of a supercharging pressure adjusting valve during feedback control.

FIG. 11 is a map showing a reference throttle opening determined by an engine speed.

FIG. 12 is a diagram showing an open control area and a feedback control area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal-combustion engine 2 Intake passage 3 Supercharger 5 Supercharging-pressure regulating valve 6 Step motor (drive means) 7 ECU (control device) 21 CAT temperature sensor (temperature sensor) 32 Catalytic converter

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenichiro Kinoshita 1-4-1 Chuo, Wako-shi, Saitama Prefecture Honda R & D Co., Ltd. (56) References Japanese Utility Model Sho-61-17141 (JP, U) 58-163639 (JP, U) JP-A 63-136231 (JP, U) JP-A 62-47746 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02B 33/00 F02B 37/18

Claims (1)

(57) [Claims] 1. A supercharger arranged in an intake passage of an internal combustion engine, a supercharging pressure adjusting valve for adjusting a supercharging pressure, a driving means for driving the adjusting valve, and a control device for controlling the means. A supercharging pressure control device for an internal combustion engine with a supercharger, comprising: a catalytic converter provided in an exhaust system of the internal combustion engine; and a temperature sensor for detecting a temperature of the catalytic converter. When the temperature of the catalytic converter detected by the temperature sensor during operation is lower than a predetermined temperature, the supercharging is performed so that the supercharging pressure in the intake passage becomes a target supercharging pressure corresponding to the temperature of the catalytic converter. A supercharging pressure control device for an internal combustion engine with a supercharger, which is configured to control an opening of a pressure regulating valve.