JP2986115B2 - Control device for supercharged engine - Google Patents

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 a supercharged engine, and more particularly to a control device for controlling a supercharging pressure so as to generate a torque corresponding to an accelerator pedal depression amount.

[0002]

2. Description of the Related Art Conventionally, in an engine with a supercharger for an automobile, when a supercharging pressure is lower than a set maximum supercharging pressure, a wastegate valve is fully closed as described in, for example, Japanese Patent Application Laid-Open No. 57-14623. When the supercharging pressure exceeds the set maximum supercharging pressure, the waste gate valve is controlled to be opened.

Further, as described in Japanese Patent Application Laid-Open No. 2-196129, a target supercharging pressure is set in accordance with a throttle opening and an engine speed, and the supercharging pressure is controlled so as to reach the target supercharging pressure. Techniques for doing so are also known. On the other hand, in recent fuel injection type automobile engines, the fuel injection amount is usually set based on the intake air amount and the engine speed.

[0004]

SUMMARY OF THE INVENTION The above-mentioned JP-A-2-196
As described in JP-A-129-129, setting a target supercharging pressure based on a throttle opening and the like and performing feedback control of the supercharging pressure so as to attain the target supercharging pressure is not enough for a sequential turbocharger or the like. In the case of a current turbocharged engine in which the state of the intake system and exhaust system fluctuates significantly, the torque fluctuation factor is large. Therefore, the same torque is not always generated even at the same supercharging pressure (boost pressure). There are problems such as lack of responsiveness at the time, and difficulty in generating actual torque as required by the accelerator pedal.

SUMMARY OF THE INVENTION An object of the present invention is to provide a turbocharged engine capable of generating a torque as required by a driver by controlling a boost pressure so that a fuel supply amount linearly corresponds to an accelerator depression amount. It is to provide a control device.

[0006]

Means for Solving the Problems A control device with a supercharger engine according to claim 1, the target supply <br/> to determine a target fuel supply amount according to the engine rotational speed depression amount of the accelerator pedal An amount calculating means, an actual supply amount calculating means for setting an actual fuel supply amount to be supplied to the engine according to an actual intake air amount or a physical amount correlated thereto and an engine speed, and a target fuel.
A supercharging pressure setting means supply amount and the actual fuel supply amount and the actual fuel supply amount based on the set the target boost pressure so as to approach the target fuel supply quantity, the actual supercharging detected by the supercharging pressure detection means And supercharging pressure control means for controlling the supercharging pressure so that the pressure becomes the target supercharging pressure.

According to a second aspect of the present invention, there is provided a control device for a supercharged engine, wherein the supercharging pressure setting means includes a target fuel supply amount and an actual fuel supply amount. The target boost pressure is set to be larger as the difference from the amount increases.

[0008]

[Action] The control device for an engine with a supercharger according to claim 1, the amount of depression of the accelerator pedal by the target supply amount calculating means and the target fuel supply amount corresponding to the engine speed is calculated, the actual supply amount depending on the physical quantity and the engine speed that is correlated with the actual intake air amount or a result calculation means
The actual fuel supply amount supplied to the engine is calculated. The supercharging pressure setting means sets the target supercharging pressure based on the target fuel supply amount and the actual fuel supply amount so that the actual fuel supply amount approaches the target fuel supply amount, and detects the supercharging pressure by the supercharging pressure control means. The supercharging pressure is controlled such that the actual supercharging pressure detected by the means becomes the target supercharging pressure.

In the control device for a supercharged engine according to a second aspect of the present invention, the supercharging pressure setting means increases the target supercharging pressure in accordance with the difference between the target fuel supply amount and the actual fuel supply amount. Set to be larger.

[0010]

According to the control apparatus for a supercharged engine according to the first aspect, the target supercharging pressure is not set in accordance with the accelerator depression amount, but in accordance with the accelerator depression amount and the engine speed. with obtaining the target fuel supply quantity, it obtains the actual fuel supply amount supplied to the engine based on the physical quantity and the engine speed that is correlated with the intake air amount or this, the actual fuel supply
Amount supply sets the target boost pressure so as to approach the target fuel supply quantity, and controls the boost pressure so that this target supercharging pressure, the actual fuel supply amount without being affected by the exhaust pressure accelerator The target boost pressure can be set so as to approach the target fuel supply amount required by the depression amount. Therefore, even if the exhaust pressure of the exhaust system and the conditions of the intake system fluctuate variously, the required amount of fuel can be supplied with good responsiveness by the accelerator pedal depression amount to generate the required torque and obtain a linear acceleration feeling. Can be done.

According to the control device for a supercharged engine according to the second aspect, basically the same effects as those of the first aspect can be obtained. In addition, the target boost pressure is set higher as the difference between the target fuel supply amount and the actual fuel supply amount increases, so that the responsiveness can be sufficiently improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. This embodiment is an embodiment in which the present invention is applied to a supercharged engine for an automobile. FIG.
As shown in the figure, an air cleaner (not shown), an air flow meter 6,
A throttle valve 8 mechanically connected to a compressor 3 and an accelerator pedal of the supercharger is provided, and a turbine 5 of the supercharger is provided in an exhaust passage 4 of the engine 1.
Further, an injector 9 for injecting fuel is provided downstream of the intake passage 2, and a bypass passage 10 for bypassing the turbine 5 in the exhaust passage 4 is provided.
Is provided with a waste gate valve 11.

The waste gate valve 11 will be described. A diaphragm 11c supporting a valve body 11a for opening and closing a waste gate 10a at an intermediate portion of a bypass passage 10 via a rod 11b divides the inside of a diaphragm casing 11d into a pressure chamber 11e and an atmosphere. And a pressure chamber 11e, and a throttle valve 8 of the intake passage 2 in the pressure chamber 11e.
A compression coil spring 11g for urging the diaphragm 11c in the normally closed direction is attached to the atmosphere chamber 11f. One end of the pressure relief passage 13 communicates with the pressure passage 12, and the other end of the pressure relief passage 13 communicates with the intake passage 2 between the compressor 3 and the air flow meter 6. A needle valve 14a for adjustment and a solenoid 14 for driving the needle valve 14a in the axial direction are provided.

The sensors will be described. In addition to the air flow meter 6, an intake air temperature sensor 15 for electrically detecting the intake air temperature upstream of the intake passage 2, and an opening for the throttle valve 8 are electrically detected. A throttle opening sensor 16;
A boost pressure sensor 17 for electrically detecting a boost pressure (boost pressure) downstream of the throttle valve 8;
Pressure sensor 18 for electrically detecting the exhaust pressure upstream of the
And a crank angle sensor 19 incorporated in the distributor to detect the rotation speed of the crankshaft. Detection signals from these sensors 6.15 to 19 are input to the control unit 20.

The control unit 20 includes an A / D converter for A / D converting an analog detection signal, a waveform shaping circuit for shaping a crank angle signal from the crank angle sensor 19, an input / output interface, a CPU and a ROM. It has a general configuration including a microcomputer including a RAM, a driving circuit for the injector 9, a driving circuit for the solenoid 14, and the like. In the ROM,
In addition to control programs for general control such as fuel control and ignition control, a control program for supercharging pressure control unique to the present application is input and stored in advance. The supercharging pressure control, in order to enhance acceleration performance by generating a torque in accordance with the depression amount of the accelerator, obtains a target fuel supply amount according to the amount of depression of the accelerator, and the target fuel supply quantity, the engine 1 The target supercharging pressure is set so as to eliminate the difference between the actual supercharging pressure and the actual fuel supply amount which is determined according to the operating state and supplied to the engine, and the solenoid 14 is operated so that the actual supercharging pressure becomes the target supercharging pressure. The supercharging pressure is controlled through the control unit.

Next, the supercharging pressure control routine will be described with reference to the flowchart of FIG. In the figure, Si
(I = 1, 2,...) Indicates each step. When the control is performed at the same time when the ignition key is turned on, necessary initial settings are executed (S1), and then the sensors 6.1 are set.
Various signals are read from 5 to 19, and necessary calculations such as calculation of the engine speed Ne are executed (S2). Next, from a map of the target fuel supply amount as shown in FIG. 3, for example, which is set in advance using the throttle opening (which corresponds to the accelerator depression amount) and the engine speed Ne as parameters, A target fuel supply amount Tpt corresponding to the throttle opening and the engine speed Ne (however, this is not for driving the injector 9) is calculated (S3). The map of FIG. 3 has a characteristic that the target fuel supply amount Tpt increases in proportion to the throttle opening when the engine speed Ne is constant.

Next, at S4, for example, as shown in FIG. 4, the engine speed Ne and the intake air amount Qa
The actual fuel supply amount Tpo corresponding to the current engine speed Ne and the intake air amount Qa is calculated from a map of the actual fuel supply amount which is set in advance using the parameters as parameters. However, in this case, the actual fuel supply amount Tpo is subjected to exhaust pressure correction based on the exhaust pressure obtained by the exhaust pressure sensor 18 and density correction based on the intake air temperature obtained by the intake air temperature sensor 15. The map in FIG. 4 is the same as a well-known map, and the vertical axis may use the intake air amount as a parameter or the boost pressure, which is a physical quantity correlated with the intake air amount Qa, as a parameter. Next, in S5, the current deviation e (n) of the fuel supply amount is e (n) = (Tpt−Tp).
Next, in step S6, the current target boost pressure Pt (n) is calculated using the PI control (proportional-integral control) formula shown in the figure. Here, Pt (n-1) is the previous target boost pressure stored while being updated in the RAM memory, KI is an integral control constant, KP is a proportional control constant, and e (n
-1) is the previous deviation stored in the RAM memory while being updated.

Next, at step S7, the target boost pressure Pt
(N) and a boost pressure deviation E (n) = Pt (n) -Po between the actual boost pressure Po detected by the boost pressure sensor 17.
Then, at S8, the duty value D (n) of the drive pulse for the solenoid 14 is calculated by the I-control (integration control) calculation formula shown in the figure. However, D (n-
1) is the previous duty value stored in the RAM memory while being updated, CI is the integral control constant, and CP is the initial value of the integral control. Next, in S9, a drive pulse having a duty value D (n) is output to the solenoid 14, and thereafter, the process returns to S2, and the routine of S2 to S9 is executed at predetermined small time intervals. Since the passage area adjusted by the needle valve 14a decreases in accordance with the increase in the duty value D (n), the relief amount of the intake air which is relieved from the pressure passage 12 to the pressure relief passage 13 decreases, and the supercharging is performed. The pressure (boost pressure) increases. On the other hand, when the supercharging pressure reaches a predetermined maximum supercharging pressure, the diaphragm 11c is switched to the atmosphere chamber 11f against the spring force of the compression coil spring 11g, and the waste gate 10a is opened, thereby preventing excessive supercharging. Will be.

The operation of the supercharging pressure control will be described. As shown in the map of FIG. 3, the target fuel supply amount Tpt
Is determined by the characteristic that is linearly proportional to the throttle opening,
Since the target boost pressure Pt (n) is set by the proportional integral control using the deviation e (n) between the target fuel supply amount Tpt and the actual fuel supply amount Tpo, the deviation e (n) is quickly eliminated. Since the target boost pressure is determined and the duty value D (n) is determined by integral control using the boost pressure deviation E (n), the solenoid 14 is controlled so that the deviation E (n) is quickly eliminated. . Therefore, when the deviation e (n) is large, the target boost pressure is controlled to be large, and the intake air amount rapidly increases, thereby increasing the actual fuel supply amount Tpo.
Rapidly increases and becomes substantially equal to the target fuel supply amount Tpo. As a result, the fuel supply amount increases linearly following the accelerator depression amount, so that a linear acceleration feeling can be obtained. In addition, since the target fuel supply amount Tpt can be ideally set in proportion to the accelerator depression amount regardless of the exhaust pressure, fuel required by the accelerator depression amount can be supplied regardless of the magnitude of the exhaust pressure.

Further, at the time of deceleration, control opposite to that described above is executed, so that the deceleration performance can be greatly improved. In particular, when the present invention is applied to an engine having a sequential turbocharger, the exhaust pressure fluctuates significantly during a transition such as when the engine is switched, and control can be performed with good responsiveness even during such a transition. In addition, although the needle valve 14a and the solenoid 14 were provided to control the supercharging pressure,
The supercharging pressure may be controlled via various types of actuators for driving the wastegate valve 11.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a supercharged engine according to an embodiment of the present invention .

FIG. 2 is a flowchart of a supercharging pressure control routine.

FIG. 3 is an explanatory diagram of a map of a target fuel supply amount.

FIG. 4 is an explanatory diagram of a map of an actual fuel supply amount.

FIG. 5 is a functional block diagram of the present invention.

[Explanation of symbols]

 Reference Signs List 6 air flow meter 12 pressure passage 14 solenoid 17 boost pressure sensor 20 control unit 11 waste gate valve 13 pressure relief passage 14a needle valve 19 crank angle sensor 20 control unit

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁶ identification code FI F02D 43/00 301 F02D 45/00 301E 45/00 301 F02B 37/12 301J (58) Investigated field (Int. Cl. ⁶ , (DB name) F02D 41/14 330 F02D 41/02 301 F02D 43/00 301 F02D 45/00 301

Claims (2)

(57) [Claims] 1. A target supply amount calculating means for obtaining a target fuel supply amount according to an accelerator pedal depression amount and an engine speed, and an actual intake air amount or a physical quantity correlated thereto and an engine speed. the actual fuel supply to be supplied to the engine Te
And the actual supply amount calculating means for setting the feed quantity, the supercharging pressure setting means for the actual fuel supply amount based on the target fuel supply amount and the actual fuel supply amount is set a target supercharging pressure so as to approach the target fuel supply quantity And supercharging pressure control means for controlling the supercharging pressure so that the actual supercharging pressure detected by the supercharging pressure detecting means becomes the target supercharging pressure. Control device. 2. The method according to claim 1, wherein the supercharging pressure setting means sets the target supercharging pressure to be larger as the difference between the target fuel supply amount and the actual fuel supply amount increases. A control device for a supercharged engine according to claim 1.