JPH05179977A - Combustion control device for engine - Google Patents

Abstract

PURPOSE:To prevent abrupt decrease of an engine speed when an engine load is increased at the time of idling operation by opening or closing auxiliary air introduction passages so as to introduce combusting auxiliary air into cylinders or operation chambers during the period other than that where fuel is injected. CONSTITUTION:A combustion control device for an engine E has direct injection type fuel injection valves 51, 51 for injecting fuel to cylinders C1, C2 of the engine E or operation chambers 3 to 5 thereof. Auxiliary air introduction passages 62A, 62B are provided for supplying auxiliary air so as to atomize the fuel when the fuel is injected from the valves 51, 51. Passage opening/closing valves 70, 70 are arranged on the passages. An engine control unit ECU opens or closes the passage opening/closing valves 70 so as to introduce the combusting auxiliary air from the auxiliary air introduction passages 62A, 62B to the cylinders C1, C2 or the operation chambers 3 to 5, during the period other than that when the fuel is injected from the valves 51, 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine combustion control device, and more particularly, to an engine intake air amount that increases rapidly when the engine load increases during idle operation. The present invention relates to an engine combustion control device capable of preventing a rapid decrease in rotation speed.

[0002]

2. Description of the Related Art An engine for a vehicle provided with a rotation speed control device during idle operation is widely put into practical use. In such an engine, generally, when the automatic transmission shifts from the N (neutral) range to the D (drive) range, or when an electric load such as a headlight or an air conditioner is turned on during idle operation, the load on the engine is relatively low. A sharp increase in idle speed can result in abrupt engine rotation or misfire. Therefore, by providing a so-called ISC (idle speed control) valve that bypasses the throttle valve and adjusting the opening degree of the ISC valve, the primary air amount is increased and the rotation is increased substantially in synchronization with the increase in load. It prevents the number from dropping sharply.

Further, as a fuel injection device for an engine, there are a direct injection type fuel injection device for directly injecting fuel into a cylinder or a working chamber of the engine, and an intake passage injection type fuel injection device for injecting fuel into an intake manifold. It has been known. Further, a technique has been proposed in which these injectors are appropriately used according to the operating state of the engine (for example,
(See JP-A-1-170722). According to such a technology, in an operating state where importance is attached to improvement of fuel efficiency by improvement of combustibility, a direct injection type fuel injection device is used to promote stratification of the air-fuel mixture, and, on the other hand, identification during idle operation is performed. In this operating state, the atomization of the fuel, that is, vaporization and atomization is emphasized, and the fuel injection device of the intake passage injection type can be used.

[0004]

However, the above-mentioned I
In an engine equipped with an SC valve, the air flowing in through the ISC valve transiently increases the pressure in the intake pipe and the intake manifold. That is, as shown in FIG. 12, the required torque of the engine is increased by applying the load (see FIG.
A), when the ISC valve opening increases rapidly (Fig. 1
2B), the pressure in the intake pipe does not increase rapidly due to the relatively large intake pipe volume, although a rapid increase in intake pipe pressure (shown by the broken line in FIG. 12C) is desired (solid line in FIG. 12C). ). Therefore, a slight time delay or response delay occurs until the intake air amount of each cylinder of the engine or the working chamber corresponds to the required torque of the engine (FIG. 12D), and as a result, the engine speed at the time of load application is changed. A sudden drop, that is, a so-called rotation drop when a load is applied may occur (FIG. 12E).

In order to prevent such a decrease in engine speed, the volume of the intake passage downstream of the throttle valve is reduced, or the so-called ISC passage is directly communicated with each cylinder, whereby the responsiveness of the engine is improved. However, such a method causes complication of the intake system structure, especially in a multi-cylinder engine, or causes a need for a plurality of ISC passages, and is extremely practically adopted. It's hard to do.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a combustion control device for an engine equipped with a direct injection type fuel injection device and an intake passage injection type fuel injection device. In particular, it is an object of the present invention to provide an engine combustion control device capable of rapidly increasing the intake air amount of the engine and preventing a rapid decrease in the engine speed when the engine load increases during idle operation.

[0007]

In order to achieve the above object, the present invention provides a combustion control device for an engine equipped with a direct injection type fuel injection device for injecting fuel into a cylinder or working chamber of the engine. An auxiliary air introduction passage for supplying auxiliary air for atomizing the injected fuel to the fuel injection device when the fuel is injected from at least the fuel injection device, and the auxiliary air introduction passage. With the passage opening / closing means provided and the passage opening / closing means for introducing the auxiliary combustion air into the cylinder or the working chamber from the auxiliary air introduction passage at a timing other than the timing of injecting fuel from the fuel injection device. A combustion control device for an engine, comprising: an opening / closing control means for controlling opening / closing of an auxiliary air introduction passage.

According to the combustion control device having the above structure, the auxiliary air introducing passage for introducing air directly into the combustion chamber is used,
Not only auxiliary air for atomizing the fuel but also combustion air is supplied to the cylinders or working chambers, whereby the intake air amount of each cylinder or working chamber can be rapidly increased.
Therefore, it is possible to increase the intake air amount without a time delay or a response delay, and to prevent a rapid decrease in the engine speed when the load changes.

The above combustion control device of the present invention can be preferably applied to a combustion control device having an intake passage injection type fuel injection device for injecting fuel into the intake passage. In a preferred embodiment of the present invention, in the idle operation region of the engine, the opening / closing control means causes the auxiliary combustion air to pass through the auxiliary air introduction passage before the timing of injecting fuel from the direct injection type fuel injection device. The auxiliary air introduction passage is opened and closed by the passage opening / closing means so that the auxiliary air introduction passage is introduced into the cylinder or the working chamber. According to this configuration, combustion air or load correction air during idle operation can be supplied to the cylinder or the working chamber through the auxiliary air introduction passage.

In one embodiment of the present invention, the opening / closing control means is arranged so that the auxiliary air for combustion is introduced into the cylinder or the working chamber immediately before the auxiliary air for atomizing fuel is introduced into the cylinder or the auxiliary air introduction passage. Alternatively, the passage opening / closing means controls the opening / closing of the auxiliary air introducing passage so that the auxiliary air introducing passage is introduced into the working chamber. According to such a configuration, it is possible to prevent the stratified mixture in the cylinder or the operation chamber from being stirred by the auxiliary air.

One embodiment of the present invention includes an intake passage having a bypass passage for bypassing a throttle valve and a bypass control means for controlling the amount of intake air passing through the bypass passage, the bypass control means being an engine. In the idle operation region, the opening / closing control of the bypass passage is performed so as to supply combustion air to the cylinder or the working chamber by the bypass passage, and the opening / closing control means supplies the auxiliary air for fuel atomization to the cylinder or the working chamber. The passage opening / closing means controls the opening / closing of the auxiliary air introducing passage so that the load correcting air is introduced into the cylinder or the working chamber via the auxiliary air introducing passage immediately before the introduction. According to this configuration, while the primary air at the time of idle operation is supplied by the ISC valve,
Load-compensating air for compensating for load fluctuations can be supplied by the auxiliary air introduction passage.

[0012] In a further preferred aspect of the present invention, the auxiliary air introducing passage has an opening opening to the cylinder or the working chamber, and the opening is arranged to close at the compression top dead center. .. This makes it possible to prevent the air-fuel mixture from flowing back or blowing back into the auxiliary air introduction passage during the compression stroke. Further, when the present invention is applied to a rotary engine, it is preferable to set the diameter of the opening to be smaller than the distance between the side outer seal and the side inner seal, and the present invention is applied to a reciprocating engine equipped with a reciprocating piston. When applying, the height of the opening is preferably set smaller than the distance between the top ring and the second ring. Thereby, generation of blow-by gas passing through the auxiliary air introducing passage can be prevented.

Further, in a further preferred aspect of the present invention, the opening / closing control means supplements the auxiliary air for correcting the engine load when a single vehicle condition for varying the engine load is satisfied. The passage opening / closing means is controlled so as to be introduced into the cylinder or the working chamber through the air introduction passage, and when a plurality of vehicle conditions are satisfied, the engine load correction auxiliary air according to each vehicle condition is provided with the time difference. The passage opening / closing means is controlled so that the air is introduced into the cylinder or the working chamber from the air introduction passage. With this configuration, the engine load can be gradually applied to effectively utilize the air supply capacity or control capacity of the auxiliary air introduction passage and the passage opening / closing means, and a large amount of auxiliary air can be temporarily supplied from the auxiliary air introduction passage. It is possible to prevent the stratified air-fuel mixture from being discharged and agitated, thereby ensuring the stratification of the fuel by the direct injection type fuel injection device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic vertical sectional view showing an embodiment of a rotary engine to which the present invention is applied. Figure 1
The Wankel type rotary engine E shown in FIG.
The first cylinder C1 and the second cylinder C2 have substantially the same structure. In FIG. 1, the elements of the corresponding cylinders are given the same reference numerals.

The first and second cylinders C1 and C2 each include a rotor 2 arranged in a rotor housing 1,
The housing 1 and the rotor 2 provide three working chambers 3,
Numbers 4 and 5 are formed in the cylinders C1 and C2, respectively. The working chambers 3, 4, 5 are sealed by an outer seal 2a and an inner seal 2b provided on the side surface of the rotor 2. Each of the working chambers 3, 4, 5 is accompanied by the revolution of the rotor 2,
The process proceeds to the intake, compression, expansion and exhaust strokes, and this cycle is repeated cyclically. In the state of the first cylinder C1 shown in FIG. 1, the working chamber 3 is in the intake stroke, the working chamber 4 is located at the compression top dead center, and the working chamber 5 is in the exhaust stroke. Further, in the state of the second cylinder C2 shown in FIG. 1, the working chamber 3 is in the compression stroke, the working chamber 4 is in the expansion stroke, and the working chamber 5 is located at the exhaust bottom dead center.

Each of the cylinders C1 and C2 is provided with first to third spark plugs 6, 7 and 8 on the trochoid peripheral wall,
The first spark plug 6 is arranged on the leading side of the rotor rotation direction with respect to the trochoid minor axis, that is, on the leading side, and the second and third spark plugs 7 and 8 are delayed in the rotor rotation direction with respect to the trochoid axis. Side, that is, the trailing side.

An intake port 11 and a communication port 12 are formed in each side housing 9 of the first and second cylinders C1 and C2. Both communication ports 12, 12 communicate with each other via a communication passage 13 having an opening / closing control valve 14. Each communication port 12 is arranged at a position closed later than the intake port 11, and the communication ports 12, 1
When one of the communication ports 2 is open to the working chamber in the intake stroke, the other of the communication ports 12 and 12 is arranged to open to the working chamber in the compression stroke.

The intake ports 11 and 11 communicate with the intake passage 21 via branch intake passages 21A and 21B, respectively, and the intake passage 21 via the throttle valve 15 and the turbochargers 22 and 23, respectively. It communicates with the air cleaner 20. The supercharger 22 is configured as a primary supercharger that constantly performs supercharging, and the supercharger 23 performs supercharging under predetermined operating conditions 2
It is configured as the next supercharger. From the intake passage 21 between the air cleaner 20 and the supercharger 22 to the bypass passage 21C
The bypass passage 21C communicates with the intake passage 21 on the downstream side of the supercharger 22 via the compressor of the supercharger 23 and the opening / closing valve 24. In addition, the bypass passage 21
C includes an intake air return path 21D that bypasses the supercharger 23,
An on-off valve 25 is arranged in the intake air return passage 21D.

An exhaust port 31 is formed in each side housing 9 of the first and second cylinders C1, C2, and each exhaust port 31 communicates with an exhaust passage 32. Exhaust passage 3
2 is a catalytic converter 3 via a turbine of the supercharger 22.
It communicates with 6. The exhaust passage 32 includes a wastegate passage 32A that bypasses the supercharger 22, and a wastegate valve 33 is arranged in the wastegate passage 32A. Further, the exhaust passage 32 includes a bypass passage 32B communicating with the catalytic converter 36 via the supercharger 23, and on-off valves 34, 35 for opening the bypass passage 32B in stages are arranged in the bypass passage 32B. ing.

The engine E constructed as described above serves as a fuel injection device in which the first fuel injection valves 51 and 51 for injecting fuel into the branch intake passages 21A and 21B, and the first and second cylinders C1 and C2 are provided. Second fuel injection valves 52, 52 for respectively injecting fuel. First fuel injection valve 51, 5
Injecting fuel into the branch intake passages 21A and 21B promotes mixing of air and fuel to increase the output of the engine E, promotes vaporization and atomization of fuel, and ignitability of air-fuel mixture. Improve. On the other hand, the second fuel injection valve 52, 52 communicates with the working chamber 3, 4 or 5 below the compression stroke via the fuel passage 53, 53 immediately before the communication port 12 is closed, and injects fuel into the working chamber. .. This makes the second
The fuel injection valves 52, 52 locally form a rich air-fuel mixture layer in the operation chamber to improve fuel efficiency by stratified combustion.

The intake passage 2 is provided upstream of the throttle valve 15.
1 is provided with an air passage 61, which communicates with the air passage 61.
Is branched into branch air passages 61A and 61B. The respective branch air passages 61A, 61B have the first fuel injection valves 51, 5
1 is supplied to each first fuel injection valve 51 to supply auxiliary air for promoting atomization or atomization of the injected fuel.

The air passage 62 having a relatively small diameter is the air passage 61.
Is connected to the intake passage 21 on the upstream side of the
An air pump 63 is interposed in the. Air pump 6
3 is driven by the driving force of the engine E transmitted via an electromagnetic clutch (not shown). Air pump 63
Is provided with a relief passage 65 capable of communicating the air passage 62 on the downstream side of the relief passage 65 with the intake passage 21, and the relief passage 65 opens the relief passage 65 at a predetermined pressure.
Has been inserted. The air passage 62 branches into branch air passages 62A and 62B on the downstream side of the air pump 63, and the branch air passages 62A and 62B are connected to the second fuel injection valves 52 and 52, respectively. The auxiliary air fed by the air pump 63 is supplied to the second fuel injection valves 52 and 52, respectively, in order to promote vaporization and atomization of the fuel injected from the second fuel injection valves 52 and 52.

The branch air passages 62A and 62B are each provided with an electromagnetic solenoid type opening / closing valve 70 for controlling opening / closing of these passages.
An on-off valve 70 is arranged below. On-off valve 70
Is for adjusting the supply of auxiliary air to the second fuel injection valve 52, and is controlled by the engine control unit ECU. The engine control unit ECU includes an engine speed sensor 101, a water temperature sensor 102, a throttle sensor 103, and an electric load sensor 1.
04 and various sensors such as the air conditioner switch 105 and further signals from the automatic transmission control unit ATU to open and close the open / close valve 70.

FIG. 2 shows the second fuel injection valve 52 and the on-off valve 7.
FIG. 3 is a vertical cross-sectional view showing the structure of No. 0, and FIG. 3 is an explanatory view schematically showing relative dimensions of the outer seal 2a, the inner seal 2b, and the fuel passage 53. As shown in FIG.
The branch air passages 62A and 62B are respectively connected to the second fuel injection valve 5
It is connected to the second nozzle portion 52a and supplies auxiliary air to the nozzle portion 52a from the side. Branch air passage 6
The on-off valve 70 inserted in 2A and 62B includes a valve body 71 and a valve seat portion 72, and opens and closes the branch air passages 62A and 62B by the movement of the valve body 71 in the axial direction. Disc 71
Is connected to the valve rod 73, and the valve rod 73 is biased in the closing direction by a tension spring 74. On-off valve 7
0 includes an electromagnetic solenoid 75 controlled by the engine control unit ECU. The electromagnetic solenoid 75 biases the valve rod 73 in the opening direction to apply the valve element 71 when the electromagnetic solenoid 75 is applied by the engine control unit ECU. The valve seat 72 is separated from the valve seat 72, thereby opening the on-off valve 70.

As shown in FIG. 3, the fuel passage 53 opens into the working chambers 4, 5 and 6 by a circular opening 53a provided in the side housing 9. Diameter d of circular opening 53a
Is set to be smaller than the distance L between the outer seal 2a and the inner seal 2b. That is, the circular opening 53a is prevented from straddling the regions on both sides of the outer seal 2a and the inner seal 2b, and blow-by gas passing through the fuel passage 53 is prevented from being generated. When the present invention is applied to a reciprocating engine using a reciprocating piston, the height of the opening of the fuel passage is set to be equal to or less than the distance between the uppermost top ring and the second ring, and preferably equal to or less than the thickness of the top ring. Good to do.

Further, as shown in FIG. 1, a circular opening 53a is formed.
Are arranged to close at compression top dead center.
More specifically, the circular opening 53a is positioned so as not to open at a position where the in-cylinder pressure exceeds the pressure of the auxiliary air pressurized by the air pump 61, whereby the backflow to the fuel passage 53 in the compression stroke or Blowback is prevented.

FIG. 4 is a diagram illustrating the operating state of the engine E, and FIG. 5 is an engine control unit E.
It is a flow chart which shows the control method of opening-and-closing valve 70 at the time of idle operation by CU. During the idle operation of the engine E, the engine control unit ECU engages the electromagnetic clutch of the air pump 63 to drive the air pump 63 and opens the on-off valve 70 based on the operating state of the engine E detected by the various sensors. However, the amount of auxiliary air corresponding to the required torque of the engine is supplied to the air passage 61, the branch air passages 62A and 62B, and the fuel passage 5.
It is supplied to the cylinders C1 and C2 via the nozzle 3. That is, the engine control unit ECU determines the amount of auxiliary air to be supplied to the cylinders C1 and C2 based on the signals from the various sensors when the rotation speed of the engine E is in the idle rotation speed region (S2 in FIG. 5). The calculation is performed (FIG. 5, S3), the opening degree of the on-off valve 70 is set by the duty signal, and the engine speed is controlled (FIG. 5, S4). As a result, engine E
Is completely supplied to the cylinders C1 and C2 via the air supply path of the second fuel injection device 52.

As shown in FIG. 4, in such an operating condition, shift range switching, air conditioner ON operation,
Alternatively, when the engine load increases due to the lighting of the headlights, etc., and the required torque of the engine E increases (FIG. 4A;
5, S1), the engine control unit ECU calculates the amount of auxiliary air to be supplied to the cylinders C1, C2 (FIG. 5, S3), resets the duty ratio of the duty signal, and sets the opening degree of the opening / closing valve 70. Increase. Thus, the amount of air supplied to the cylinders C1, C2 via the opening / closing valve 70 is increased (FIG. 4B). The volumes of the branch air passages 61A, 61B and the fuel passage 53 are relatively small, and therefore the cylinders C1,
Since the intake air amount of C2 increases rapidly (Fig. 4C),
The engine speed does not decrease sharply, and so-called engine rotation drop is hindered (Fig. 4D).

FIG. 6 is a diagram showing the timing of supplying auxiliary air to the cylinders C1 and C2. The auxiliary air is supplied to the nozzle portion 52a of the second fuel injection valve 52 in synchronization with the fuel injection timing, and has a function of promoting atomization or vaporization atomization of the fuel injected from the second fuel injection valve 52. At the same time, as described above, it has a function as combustion air during idle operation and load correction air during load application. The second fuel injection valve 52 is originally a fuel injection that emphasizes stratification of the air-fuel mixture, and the auxiliary air as the combustion air and the load correction air should be supplied so as not to stir the air-fuel mixture. .. Therefore, in order not to impair the stratification of the fuel by the direct injection, as shown by the line (A) or the line (B) in FIG. 6, a timing slightly earlier than the atomizing air, that is,
Immediately before the atomizing air, the combustion air and the load correcting air are supplied.

Thus, the engine E of the above embodiment is
Intake passage injection type first fuel injection valves 51, 51 for injecting fuel into the branch intake passages 21A, 21B, respectively, and direct injection type second fuel for injecting fuel into the first and second cylinders C1, C2, respectively. And injection valves 52, 52. The second fuel injection valve 52 for injecting fuel into the working chamber 3, 4 or 5 below the compression stroke includes an air passage 62 and a branch air passage 62A.
62B is connected, and auxiliary air for promoting atomization or vaporization atomization of the fuel injected from the second fuel injection valves 52, 52 through the air passage 62 is the second fuel injection valve 52.
Is supplied to. In the branch air passages 62A and 62B,
An on-off valve 70 is arranged, and the opening degree of the on-off valve 70 is controlled by the engine control unit ECU. In the engine E, the air passage 62 and the branch air passages 62A and 62B are used as a means for supplying combustion air to the engine E during idle operation, and for load correction for compensating the load fluctuation of the engine E. Used as an air supply unit, the engine control unit ECU supplies auxiliary air to the cylinders C1, C2 through the branch air passages 62A, 62B and the fuel passage 53 by controlling the opening degree of the opening / closing valve 70. .. The volumes of the branch air passages 62A and 62B and the fuel passage 53 are extremely smaller than those of the branch intake passages 21A and 21B, so that the intake air amounts of the cylinders C1 and C2 increase rapidly. Thus, the engine E rapidly increases the intake air amount when the engine load increases, and does not cause a rapid decrease in the engine speed.

Further, the circular opening 53a of the fuel passage 53 is
The diameter d is set smaller than the distance L between the outer seal 2a and the inner seal 2b, and blowby gas can be prevented from passing through the circular opening 53a and the fuel passage 53. FIG. 7 is a schematic vertical sectional view of a rotary engine showing another embodiment of the present invention, and FIG. 8 is a diagram illustrating an operating state of the engine shown in FIG. Further, FIG. 9 is a flowchart showing a control method by the engine control unit ECU during idle operation.

In the engine E shown in FIG. 7, a bypass passage 80 bypassing the throttle valve 15 is provided in the intake system, and an electromagnetic solenoid type BAC is provided in the bypass passage 80.
A (bypass air control) valve 81 is provided. The opening degree of the BAC valve 81 is controlled by the engine control unit ECU to adjust the engine intake air amount during idle operation.

During idle operation of the engine E, the engine control unit ECU engages the electromagnetic clutch of the air pump 63 to drive the air pump 63 and, based on the operating state of the engine E, the BAC valve 8
The opening degree of No. 1 is controlled, and the intake air of the air amount corresponding to the required torque of the engine is supplied to the cylinders C1 and C2 through the intake passage 21, the bypass passage 80, and the branch intake passages 21A and 21B (FIG. 9, S2, S3). Further, when the required torque of the engine E increases due to switching of the shift range or application of an electric load, the engine control unit EC
U calculates the amount of intake air to be supplied to the cylinders C1 and C2 (FIG. 9, S1, S3), increases the opening degree of the BAC valve 81 (FIG. 8A), and the shortage of intake air passing through the BAC valve 81 ( 8A, the auxiliary air amount corresponding to the symbol a) is calculated, and the opening degree of the opening / closing valve 70 is increased (FIG. 9, S4,
S5; FIG. 8B, symbol b). Thus, the BAC valve 81
The intake air passing through and the auxiliary air supplied to the cylinders C1 and C2 via the opening / closing valve 70 are supplied to the cylinders C1 and C2. As a result, the intake amount of the cylinders C1 and C2 rapidly increases, and
As shown in C, a rapid decrease in engine speed is prevented.

When the engine E is not idle and the amount of auxiliary air passing through the opening / closing valve 70 is a prescribed amount determined by fuel injection (FIGS. 9, S2, S6), the fuel is atomized. The auxiliary air amount is maintained (S7 in FIG. 9).
FIG. 10 shows an operating state of the rotary engine in still another embodiment of the present invention, and FIG. 11 is a flowchart showing a control method by the engine control unit ECU for achieving the operating state of FIG.

In general, various loads are imposed on the engine at arbitrary timing by switching the shift range, electric load, and the like. When multiple engine loads are turned on at the same time,
A situation in which the auxiliary air supply passage or the air supply capacity or control capacity of the opening / closing valve 70 is exceeded may transiently occur. Also,
As described above, the second fuel injection valve 52 is intended to locally form a rich air-fuel mixture layer in the operation chamber to improve fuel efficiency by stratified combustion, but a large amount of auxiliary air is supplied from the fuel passage 53. When discharged, the stratification of fuel may be impaired. 10 and 11 show an embodiment equipped with means for coping with such a situation.

Engine control unit EC of this example
When the vehicle is operated or controlled to change the engine load, U sets the opening of the BAC valve (FIGS. 11, S1 and S3), and when the engine load changes,
It is determined whether the supply capacity or control capacity of the auxiliary intake air can correspond (S4). If auxiliary intake is possible, the engine load is allowed to be input (S5), the amount of auxiliary air corresponding to the shortage of intake air that passes through the BAC valve is calculated, and the opening / closing valve is opened to supply auxiliary air to each cylinder. Increase (S6,
S7).

However, the supply capacity or control capacity of the auxiliary intake air cannot cope with changes in engine load, and
When the application of the engine load is requested by more than one kind of vehicle operation or control (FIG. 10A; FIG. 11, S4, S8), only the engine load to be applied with priority is applied (S).
9). For example, as shown in FIG. 10A, the load signals of the loads 1 and 2 are transmitted to the engine control unit EC at time t1.
When a plurality of vehicle conditions input to U and varying the engine load are satisfied, at time t1, the load a with high priority a
Then, only the auxiliary air amount b1 (c1) for obtaining the required engine torque a1 corresponding to the load 1 is supplied to each cylinder. Then, at time t2 when a short time has passed, the second
Load 2 is supplied, and the auxiliary air amount b2 (c2) for obtaining the required torque a2 of the engine corresponding to the load 2 is supplied to each cylinder. Thus, since the engine load is gradually input, the air supply capacity or control capacity of the auxiliary air supply passage and the on-off valve can be efficiently used, and as shown in FIG. The drop is avoided. Further, it is possible to prevent a large amount of auxiliary air from being discharged from the fuel passage at one time, and it is possible to ensure stratification of the fuel.

Although the preferred embodiment of the present invention has been described above, it is needless to say that the present invention is not limited to the above embodiment and various modifications and changes can be made. For example, although the above embodiments relate to a rotary engine, the present invention may be applied to a reciprocating engine equipped with a reciprocating piston. Also, the on-off valve 7
0 is not limited to the illustrated structure, and may have another structure.

[0039]

As described above, according to the present invention,
In a combustion control device for an engine including a direct injection type fuel injection device and an intake passage injection type fuel injection device,
In particular, when the engine load increases during idle operation, it is possible to provide an engine combustion control device that can rapidly increase the intake air amount of the engine and prevent a sudden decrease in engine speed.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing an embodiment of a rotary engine to which the present invention is applied.

FIG. 2 is a vertical cross-sectional view showing structures of a second fuel injection valve and an opening / closing valve shown in FIG.

FIG. 3 is an explanatory view schematically showing relative dimensions of an outer seal and an inner seal of the rotor shown in FIG. 1 and a fuel passage of a second fuel injection valve.

4 is a diagram exemplarily showing an operating state of the engine shown in FIG. 1. FIG.

FIG. 5 is a flowchart showing a method of controlling an on-off valve during idle operation by an engine control unit.

FIG. 6 is a diagram showing the timing of supplying auxiliary air to each cylinder.

FIG. 7 is a schematic vertical sectional view of a rotary engine showing another embodiment of the present invention.

FIG. 8 is a diagram illustrating an operating state of the engine shown in FIG. 7.

9 is a flowchart showing a control method at the time of idling operation by the engine control unit shown in FIG.

FIG. 10 is a diagram showing an operating state of a rotary engine according to still another embodiment of the present invention.

11 is a flowchart showing a control method by an engine control unit for achieving the operating state of FIG.

FIG. 12 is a diagram showing an operating state of a conventional rotary engine.

[Explanation of symbols]

 E Engine C1, C2 Cylinder ECU Engine control unit 1 Rotor housing 2 Rotor 2a Outer seal 2b Inner seal 3, 4, 5 Working chamber 6, 7, 8 Spark plug 11 Intake port 21 Intake passage 21A, 21B Branch intake passage 51 First fuel Injection valve 52 Second fuel injection valve 53 Fuel passage 62 Air passage 62A, 62B Branch air passage 63 Air pump 70 Open / close valve 80 Bypass passage 81 BAC (Bypass air control) valve

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Haruo Okimoto 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (9)

[Claims] 1. A combustion control device for an engine, comprising a direct injection type fuel injection device for injecting fuel into a cylinder or a working chamber of an engine, wherein the fuel injection is performed at least when the fuel is injected from the fuel injection device. Auxiliary air introducing passage for supplying auxiliary air for atomizing the injected fuel to the device, passage opening / closing means arranged in the auxiliary air introducing passage, and fuel injection from the fuel injection device An opening / closing control unit that controls opening / closing of the auxiliary air introduction passage by the passage opening / closing unit to introduce the auxiliary combustion air from the auxiliary air introduction passage into the cylinder or the working chamber at a time other than the time Combustion control device for the engine. 2. The combustion control device for an engine according to claim 1, wherein an intake passage fuel injection device for injecting fuel into the intake passage is provided in the intake passage. 3. In an engine idle operation region,
The opening / closing control means is configured to introduce the auxiliary combustion air into the cylinder or the working chamber through the auxiliary air introduction passage before the time of injecting fuel from the direct injection type fuel injection device. The combustion control device for an engine according to claim 1 or 2, wherein the auxiliary air introduction passage is controlled to be opened and closed by means of. 4. The opening / closing control means introduces auxiliary combustion air into the cylinder or the working chamber via the auxiliary air introduction passage immediately before introducing the auxiliary air for atomizing the fuel into the cylinder or the working chamber. The combustion control device for the engine according to claim 1, wherein the passage opening / closing means controls opening / closing of the auxiliary air introduction passage. 5. An intake passage including a bypass passage for bypassing a throttle valve and a bypass control means for controlling an intake air amount passing through the bypass passage, the bypass control means comprising the bypass passage in an idle operation region of an engine. The bypass passage is controlled to be opened and closed so as to supply combustion air to the cylinder or the working chamber by a passage, and the opening / closing control means is for correcting the load immediately before introducing the auxiliary air for atomizing the fuel into the cylinder or the working chamber. The combustion control apparatus for the engine according to claim 3, wherein the passage opening / closing means controls opening / closing of the auxiliary air introducing passage so that air is introduced into the cylinder or the working chamber through the auxiliary air introducing passage. .. 6. The auxiliary air introducing passage has an opening that opens to the cylinder or the working chamber, and the opening is arranged so as to close at the compression top dead center. 6. The combustion control device for the engine according to any one of items 1 to 5. 7. The engine combustion according to claim 6, wherein the engine is a rotary engine, and a diameter of the opening is set to be smaller than a distance between the side outer seal and the side inner seal. Control device. 8. The reciprocating engine having a reciprocating piston, wherein the height of the opening is set smaller than the distance between the top ring and the second ring. Engine combustion control device. 9. The opening / closing control means, when a single vehicle condition for varying the engine load is satisfied, supplies the auxiliary air for correcting the engine load to the cylinder or the working chamber through the auxiliary air introduction passage. The passage opening / closing means is controlled so as to be introduced into the vehicle, and when a plurality of vehicle conditions are satisfied, auxiliary air for engine load correction according to each vehicle condition,
4. The combustion control device for an engine according to claim 3, wherein the passage opening / closing means is controlled so as to introduce the auxiliary air into the cylinder or the working chamber with a time lag.