JP4367273B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention provides first fuel injection means (in-cylinder injector) for injecting fuel into the cylinder and second fuel injection means (intake passage injection) for injecting fuel into the intake passage or intake port. The present invention relates to a control device for an internal combustion engine provided with a fuel injector, and more particularly to control when a purge process of fuel evaporative gas is executed.

  A first fuel injection valve for injecting fuel into the engine intake passage (in the background art, an intake passage injection injector) and a second fuel injection valve for injecting fuel constantly into the engine combustion chamber (background) In the technology, an in-cylinder injector) is provided, and when the engine load is lower than a predetermined set load, the fuel injection from the first fuel injection valve (intake passage injector) is stopped and the engine load is stopped. An internal combustion engine is known in which fuel is injected from a first fuel injection valve (intake passage injector) when is higher than a set load. In this internal combustion engine, a total injection amount, which is the sum of fuels injected from both fuel injection valves, is predetermined as a function of the engine load, and this total injection amount is increased as the engine load increases.

  Japanese Patent Application Laid-Open No. 5-231221 (Patent Document 1) discloses a fuel injection type internal combustion engine that prevents fluctuations in engine output torque at the start and stop of fuel injection by an intake passage injector in such an internal combustion engine. Is disclosed. The fuel injection type internal combustion engine includes a first fuel injection valve for injecting fuel into the engine intake passage and a second fuel injection valve for injecting fuel into the engine combustion chamber. When the operating state is within a predetermined operating range, fuel injection from the first fuel injection valve is stopped, and when the operating state of the engine is outside the predetermined operating range, fuel is supplied from the first fuel injection valve. In an internal combustion engine that injects fuel, the amount of attached fuel adhering to the inner wall surface of the intake passage when fuel injection from the first fuel injection valve is started is estimated, and fuel injection from the first fuel injection valve is stopped Means for estimating the amount of adhering fuel flowing into the combustion chamber of the engine when it is When fuel injection from the first fuel injection valve is started, the amount of fuel injected from the second fuel injection valve is corrected to be increased by the amount of attached fuel, and fuel injection from the first fuel injection valve is stopped In addition, the amount of fuel injected from the second fuel injection valve is corrected to decrease by the amount of inflow.

According to this fuel injection type internal combustion engine, when the fuel injection from the first fuel injection valve is started, the amount of fuel injected from the second fuel injection valve is corrected to increase by the amount of attached fuel, thereby actually entering the engine combustion chamber. The amount of fuel supplied becomes the required fuel amount, and when the fuel injection from the first fuel injection valve is stopped, the amount of fuel injected from the second fuel injection valve is corrected to decrease by the inflow amount, so that the engine combustion chamber actually The amount of fuel supplied to is the required fuel amount. As a result, it is possible to prevent the engine output torque from changing when the fuel injection from the first fuel injection valve is started and stopped.
JP-A-5-2321221

  Generally, in a vehicle equipped with an internal combustion engine, evaporated fuel (paper) from a fuel tank or the like is temporarily adsorbed to a collection device such as a canister, and the canister or the like is collected according to the operating state of the internal combustion engine. By purging the fuel evaporative gas adsorbed by the apparatus and introducing it into the intake system of the internal combustion engine, the fuel evaporative gas is prevented from being diffused into the atmosphere.

  Thus, at the time of performing the purge process of purging the fuel evaporative gas and introducing it into the intake system of the internal combustion engine, the purge fuel amount depending on the concentration of the fuel evaporative gas to be purged, so-called purge gas concentration and its flow rate, is In addition to the amount of fuel injected from the injector, it is introduced into the engine. As a result, the air-fuel ratio fluctuates and the combustion deteriorates. Therefore, when performing such a purge process, the fuel injection amount is corrected to reduce the performance of the internal combustion engine or the emission. Is required to avoid.

  However, the above-mentioned Patent Document 1 does not describe the correction of the fuel injection amount when executing such a purge process. Therefore, according to the fuel injection type internal combustion engine disclosed in Patent Document 1, even when the engine output torque can be prevented from fluctuating at the start and stop of fuel injection from the first fuel injection valve, Problems (for example, performance deterioration due to deposit adhesion, emission deterioration due to fluctuation of air-fuel ratio) cannot be solved.

  The present invention has been made to solve the above-described problems, and has as its object the first fuel injection means for injecting fuel into the cylinder and the second fuel injection means for injecting fuel into the intake passage. In the internal combustion engine that shares the injected fuel, it is possible to provide a control device for the internal combustion engine that can avoid deterioration in performance and emission of the internal combustion engine during purge processing.

  A control device according to a first aspect of the present invention comprises a first fuel injection means for injecting fuel into a cylinder and a second fuel injection means for injecting fuel into an intake passage, The internal combustion engine that executes the purge process is controlled. The control device is a control for controlling the fuel injection means so that the fuel is injected by the first fuel injection means and the second fuel injection means based on conditions required for the internal combustion engine. And the fuel injection means are controlled so that the correction of the fuel injection amount corresponding to the introduced purge fuel amount is shared by the first fuel injection means and the second fuel injection means when the purge process is executed. Purge control means. The purge control means does not change the ratio of the fuel injection amount of the first fuel injection means to the total supply fuel amount in the region where the fuel injection is shared by the first fuel injection means and the second fuel injection means. Means for controlling the fuel injection means.

  According to the first invention, when the purge process is executed by the purge control means, the ratio of the fuel injected from the first fuel injection means (for example, the in-cylinder injector) (the ratio to the total supply fuel) is The fuel injection amount corresponding to the introduced purge fuel amount is corrected so as not to change. As a result, the amount of fuel injected from the in-cylinder injector does not change if all the supplied fuel is the same before and after the purge process. As a result, when the amount of fuel injected from the in-cylinder injector is compared with, for example, a case where the fuel injection amount corresponding to the purge fuel amount is decreased corresponding to the sharing ratio, the tip temperature of the in-cylinder injector Therefore, deposit accumulation can be prevented. Further, since the in-cylinder injector injects at a high pressure, the variation in the injection amount is larger than that of the second fuel injection means (for example, an intake passage injector) that injects at a low pressure. If the fuel injection amount from the in-cylinder injector is decreased, the learning value of the air-fuel ratio control before the purge process is executed cannot be applied due to the variation. On the other hand, this learning value can be applied if the amount of fuel injected from the in-cylinder injector is not changed as in the first invention. Furthermore, if the fuel injection amount from the in-cylinder injector is reduced to near the minimum fuel injection amount, there may be a region where there is no linearity in the relationship between the actual injection amount and the fuel injection period. For this reason, if the amount of fuel injection from the in-cylinder injector is decreased, a larger problem may occur. On the other hand, such a problem can be avoided if the amount of fuel injected from the in-cylinder injector is not changed as in the first invention. In this way, when performing the purge process, the fuel injection amount corresponding to the purge fuel amount is corrected by changing the fuel injection amount from the intake manifold injector instead of the fuel injection amount from the in-cylinder injector. As a result, the overall air-fuel ratio control can be satisfied, so that the emission can be prevented from deteriorating, and the engine performance can be prevented from deteriorating due to deposit adhesion. As a result, in the internal combustion engine that shares the injected fuel with the in-cylinder injector and the intake manifold injector, control of the internal combustion engine that can avoid deterioration in performance and emission of the internal combustion engine when performing the purge process is performed. An apparatus can be provided.

  In the control device according to the second aspect of the invention, in addition to the configuration of the first aspect of the invention, the purge control means includes means for controlling the fuel injection amount from the first fuel injection means so as not to change.

  According to the second aspect of the invention, the fuel injection amount from the in-cylinder injector is not changed when the purge process is executed, so that the fuel from the intake passage injection injector is not the fuel injection amount from the in-cylinder injector. By changing the injection amount, the fuel injection amount corresponding to the purge fuel amount is corrected, and the overall air-fuel ratio control can be satisfied. For this reason, it is possible to prevent the emission from being deteriorated and to prevent the engine performance from being deteriorated due to the deposit.

  In the control device according to the third invention, in addition to the configuration of the first invention, the purge control means includes means for controlling so as to change only the fuel injection amount of the second fuel injection means.

  According to the third aspect of the invention, when the purge process is executed, the fuel injection amount corresponding to the purge fuel amount is corrected by changing only the fuel injection amount from the intake passage injector, and the overall air-fuel ratio control is performed. Can be satisfied. For this reason, the deterioration of the emission can be prevented. Further, since the fuel injection amount from the in-cylinder injector is not reduced, the injection port portion of the in-cylinder injector does not reach a high temperature, so that deterioration in engine performance due to deposit adhesion can be prevented.

  In the control device according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the purge control means subtracts the purge fuel amount from the basic fuel injection amount of the second fuel injection means. Means for controlling to inject the fuel injection amount calculated by the second fuel injection means.

  According to the fourth invention, the in-cylinder injector is obtained by subtracting the purge fuel amount from the fuel injection amount from the intake passage injector in the basic fuel amount determined from the rotational speed and load factor of the internal combustion engine. Do not change the fuel injection amount from. For this reason, since the air-fuel ratio control as a whole can be satisfied, the deterioration of the emission can be prevented. Further, since the fuel injection amount from the in-cylinder injector is not reduced, the injection port portion of the in-cylinder injector does not reach a high temperature, so that deterioration in engine performance due to deposit adhesion can be prevented.

  In the control device according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the first fuel injection means is an in-cylinder injector, and the second fuel injection means is An intake passage injector.

  According to a fifth aspect of the present invention, there is provided an internal combustion engine in which an in-cylinder injector that is a first fuel injection means and an intake passage injection injector that is a second fuel injection means are separately provided to share injected fuel. It is possible to provide a control device for an internal combustion engine that can avoid deterioration in performance of the internal combustion engine and deterioration in emission during processing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  FIG. 1 shows a schematic configuration diagram of an engine system controlled by an engine ECU (Electronic Control Unit) which is a control device for an internal combustion engine according to an embodiment of the present invention. Although FIG. 1 shows an in-line four-cylinder gasoline engine as the engine, the present invention is not limited to such an engine.

  As shown in FIG. 1, the engine 10 includes four cylinders 112, and each cylinder 112 is connected to a common surge tank 30 via a corresponding intake manifold 20. The surge tank 30 is connected to an air cleaner 50 via an intake duct 40, an air flow meter 42 is disposed in the intake duct 40, and a throttle valve 70 driven by an electric motor 60 is disposed. The opening degree of throttle valve 70 is controlled based on the output signal of engine ECU 300 independently of accelerator pedal 100. On the other hand, each cylinder 112 is connected to a common exhaust manifold 80, and this exhaust manifold 80 is connected to a three-way catalytic converter 90.

  For each cylinder 112, an in-cylinder injector 110 for injecting fuel into the cylinder, and an intake passage injection injector 120 for injecting fuel into the intake port or / and the intake passage. And are provided respectively. These injectors 110 and 120 are controlled based on the output signal of engine ECU 300, respectively. The in-cylinder injectors 110 are connected to a common fuel distribution pipe 130, and this fuel distribution pipe 130 is connected to the fuel distribution pipe 130 through a check valve 140, and is driven by an engine. A high-pressure fuel pump 150 is connected. In the present embodiment, an internal combustion engine in which two injectors are separately provided will be described, but the present invention is not limited to such an internal combustion engine. For example, it may be an internal combustion engine having one injector having both an in-cylinder injection function and an intake passage injection function.

  As shown in FIG. 1, the discharge side of the high-pressure fuel pump 150 is connected to the suction side of the high-pressure fuel pump 150 via an electromagnetic spill valve 152. When the amount of fuel supplied from the pump 150 into the fuel distribution pipe 130 is increased and the electromagnetic spill valve 152 is fully opened, the fuel supply from the high pressure fuel pump 150 to the fuel distribution pipe 130 is stopped. ing. Electromagnetic spill valve 152 is controlled based on the output signal of engine ECU 300.

  On the other hand, each intake passage injector 120 is connected to a common low-pressure fuel distribution pipe 160, and the fuel distribution pipe 160 and the high-pressure fuel pump 150 are connected to a common fuel pressure regulator 170 through an electric motor drive type. The low-pressure fuel pump 180 is connected. Further, the low pressure fuel pump 180 is connected to the fuel tank 200 via a fuel filter 190. The fuel pressure regulator 170 returns a part of the fuel discharged from the low-pressure fuel pump 180 to the fuel tank 200 when the fuel pressure of the fuel discharged from the low-pressure fuel pump 180 becomes higher than a predetermined set fuel pressure. Accordingly, the fuel pressure supplied to the intake manifold injector 120 and the fuel pressure supplied to the high-pressure fuel pump 150 are prevented from becoming higher than the set fuel pressure.

  The engine ECU 300 is composed of a digital computer, and is connected to each other via a bidirectional bus 310, a ROM (Read Only Memory) 320, a RAM (Random Access Memory) 330, a CPU (Central Processing Unit) 340, and an input port 350. And an output port 360.

  The air flow meter 42 generates an output voltage proportional to the amount of intake air, and the output voltage of the air flow meter 42 is input to the input port 350 via the A / D converter 370. A water temperature sensor 380 that generates an output voltage proportional to the engine cooling water temperature is attached to the engine 10, and the output voltage of the water temperature sensor 380 is input to the input port 350 via the A / D converter 390.

  A fuel pressure sensor 400 that generates an output voltage proportional to the fuel pressure in the fuel distribution pipe 130 is attached to the fuel distribution pipe 130, and the output voltage of the fuel pressure sensor 400 is input via the A / D converter 410. Input to port 350. The exhaust manifold 80 upstream of the three-way catalytic converter 90 is provided with an air-fuel ratio sensor 420 that generates an output voltage proportional to the oxygen concentration in the exhaust gas. The output voltage of the air-fuel ratio sensor 420 is converted into an A / D converter. It is input to the input port 350 via 430.

The air-fuel ratio sensor 420 in the engine system according to the present embodiment is a global air-fuel ratio sensor (linear air-fuel ratio sensor) that generates an output voltage proportional to the air-fuel ratio of the air-fuel mixture burned by the engine 10. The air-fuel ratio sensor 420 may be an O ₂ sensor that detects whether the air-fuel ratio of the air-fuel mixture burned in the engine 10 is rich or lean with respect to the stoichiometric air-fuel ratio. Good.

  The accelerator pedal 100 is connected to an accelerator opening sensor 440 that generates an output voltage proportional to the depression amount of the accelerator pedal 100, and the output voltage of the accelerator opening sensor 440 is input to the input port 350 via the A / D converter 450. Is input. The input port 350 is connected to a rotational speed sensor 460 that generates an output pulse representing the engine rotational speed. In the ROM 320 of the engine ECU 300, the value of the fuel injection amount and the engine cooling that are set according to the operating state based on the engine load factor and the engine speed obtained by the accelerator opening sensor 440 and the engine speed sensor 460 described above are stored. Correction values based on the water temperature and the like are previously mapped and stored.

  On the other hand, a canister 230, which is a collection container for collecting fuel evaporative gas generated in the fuel tank 200, is connected to the fuel tank 200 via a paper passage 260, and further, the canister 230 collects the fuel collected therein. It is connected to a purge passage 280 for supplying evaporated gas to the intake system of the engine 10. The purge passage 280 communicates with a purge port 290 opened downstream of the throttle valve 70 of the intake duct 40. As is well known, the canister 230 is filled with an adsorbent (activated carbon) that adsorbs fuel evaporative gas, and an atmospheric passage for introducing the atmosphere into the canister 230 via a check valve during purging. 270 is provided. Further, the purge passage 280 is provided with a purge control valve 250 for controlling the purge amount, and the opening degree of the purge control valve 250 is duty-controlled by the engine ECU 300 so that the purge process is performed in the canister 230. The fuel evaporative gas amount, and hence the amount of fuel introduced into the engine 10 (hereinafter referred to as purge fuel amount) is controlled.

  FIG. 2 shows a map representing the injection ratio (hereinafter also referred to as direct injection ratio, DI ratio (r)) between in-cylinder injector 110 and intake manifold injector 120 stored in ROM 320 of engine ECU 300. Will be described. As shown in FIG. 2, this map shows the engine rotation speed on the horizontal axis, the load factor on the vertical axis, and the share ratio of the in-cylinder injector 110 as a percentage as the direct injection ratio (DI ratio r). Has been.

  As shown in FIG. 2, a direct injection ratio (DI ratio r) is set for each operation region determined by the engine speed and the load factor. “Direct injection 100%” means a region where fuel injection is performed only from the in-cylinder injector 110 (r = 1.0, r = 100%), and “direct injection 0-20%”. Means that the fuel injection from the in-cylinder injector 110 is a region (r = 0 to 0.2) that is 0 to 20% of the total injection amount. For example, “direct injection 40%” indicates that 40% of the total injection amount is injected from the in-cylinder injector 110 and 60% of the total injection amount is injected from the intake manifold injector 120.

  With reference to FIG. 3, a control structure of a program executed by engine ECU 300 which is a control device according to the embodiment of the present invention will be described.

  The flowchart shown in FIG. 3 shows the determination of the presence or absence of refueling by, for example, comparing and calculating the current fuel gauge value of the fuel gauge and the fuel gauge value recorded when the engine is stopped after the engine 10 is started. Alternatively, the amount of fuel evaporative gas collected in the canister 230 is estimated based on the change in temperature while the engine is stopped, etc., and it is determined whether purge processing is necessary. When the purge process is necessary and possible, the purge gas concentration detection and purge process execution control routine according to the flowchart shown in FIG. 3 is started. The case where the purge process is possible includes, for example, a low-speed and low-load operation state in which the intake negative pressure of the engine 10 is sufficiently generated.

  In step (hereinafter, step is abbreviated as S) 300, engine ECU 300 controls purge control valve 250 to be opened instantaneously in a small opening state. When the purge control valve 250 is opened at a small opening, the purge gas including the fuel evaporation gas is introduced into the engine 10 through the purge passage 280 and the purge port 290.

  In S310, engine ECU 300 detects the air-fuel ratio (A / F) of the combustion gas when purge gas is introduced by air-fuel ratio sensor 420.

  In S320, engine ECU 300 obtains the purge gas concentration based on the detected air-fuel ratio (A / F). Specifically, since the air-fuel ratio after introduction becomes richer than the air-fuel ratio before introduction of purge gas, the purge gas concentration is obtained from the degree of richness. The relationship between the two is obtained in advance through experiments and mapped and stored in the ROM 320. The obtained purge gas concentration is stored in the RAM 330.

  In S330, engine ECU 300 performs duty control on the opening of purge control valve 250 for a predetermined time so that the amount of purge fuel introduced into engine 10 is constant based on the purge gas concentration stored in RAM 330. Execute control. In S340, engine ECU 300 sets the purge control execution flag to the ON state during the process in S330.

  The purge fuel amount means the amount of fuel contained in the purge gas, and the opening degree of the purge control valve 250 is duty-controlled so as to be constant regardless of the change in the suction negative pressure accompanying the fluctuation of the operation state. The purge gas flow rate is controlled. The duty ratio at this time is also obtained in advance through experiments using the purge gas concentration and the suction negative pressure as parameters and stored in the ROM 320.

  With reference to FIG. 4, a control structure of a program for correcting the purge fuel amount when the purge control is being executed will be described. The control program shown in FIG. 4 is executed every predetermined time or every predetermined crank angle.

  In S400, engine ECU 300 determines whether or not the purge control execution flag is on. If the purge control execution flag is on (YES in S400), the process proceeds to S410. Otherwise (NO in S400), this process ends.

  In S410, engine ECU 300 calculates an injection distribution ratio (DI ratio) r. At this time, the injection ratio (DI ratio) r is calculated using the map shown in FIG.

In S420, engine ECU 300 calculates basic injection amounts of in-cylinder injector 110 (DI) and intake passage injector 120 (PFI). At this time, the basic injection amount taudb of the in-cylinder injector 110 is
taudb = r × EQMAX × klfwd × fafd × kgd × kpr (1)
Is calculated by The basic injection amount taupb of the intake passage injector 120 is:
taupb = k × (1-r) × EQMAX × klfwd × fafp × kgp (2)
Is calculated as In the above equations (1) and (2), r is the injection ratio (DI ratio), EQMAX is the maximum injection amount, klfwd is the load factor, and fafd and fafp are in the stoichiometric state. It is a feedback coefficient, kgd is a learned value of the in-cylinder injector 110, kpr is a conversion coefficient corresponding to the fuel pressure, and kgp is a learned value of the intake manifold injector 120.

  In S430, engine ECU 300 determines whether or not DI ratio r is zero. If DI ratio r is 0 (YES in S430), the process proceeds to S440. If not (NO in S430), the process proceeds to S460.

In S440, engine ECU 300 substitutes purge correction value fpg corresponding to the purge fuel amount described above into purge reduction calculation value fpgp on intake manifold injector 120 side. In S450, engine ECU 300 calculates final injection amount taup of intake manifold injector 120. At this time, the injection amount taup is
taup = taub-fpgp + tauv (3)
Is calculated by In the above equation (3), tauv is an invalid injection amount.

  In S460, engine ECU 300 determines whether DI ratio r is 1 or not. If DI ratio r is 1 (YES in S460), the process proceeds to S470. If not (NO in S460), the process proceeds to S480.

  In S470, engine ECU 300 substitutes fpg for purge reduction calculation value fpgd on in-cylinder injector 110 side. Also, 0 is substituted for the purge reduction calculation value fpgp of the intake manifold injector 120.

  In S480, engine ECU 300 substitutes 0 for purge reduction calculation value fpgd of in-cylinder injector 110. Further, fpg is substituted into the purge reduction amount calculation value fpgp of the intake manifold injector 120.

In S490, engine ECU 300 calculates final injection amounts taud and taup of in-cylinder injector 110 and intake passage injector 120. At this time, the final injection amount taud of the in-cylinder injector 110 is
taud = taudb−fpgd (4)
Is calculated by Further, the final injection amount taup of the intake passage injector 120 is calculated by the above equation (3).

Summarizing the purge reduction calculation value,
When DI ratio r = 1.0 fpgd = fpg (fpgp = 0) (5)
When DI ratio r ≠ 1.0 fpgd = 0, fpgp = fpg (6)
It becomes.

  Based on the above-described structure and flowchart, the spray distribution control during the purge process of engine 10 executed by engine ECU 300 that is the control apparatus according to the present embodiment will be described. In the following description, the purge process will be described.

  Based on the map shown in FIG. 2, when the injection division control between the in-cylinder injector 110 and the intake manifold injector 120 is being performed and the purge process is executed, the DI ratio r is 1.0. In this case, the purge reduction calculated value fpg (= fpgd) is subtracted from the basic injection amount taudb of the in-cylinder injector 110. This is when the DI ratio r shown in FIGS. 5A and 5B is 100%.

  When the DI ratio r is neither 100% nor 0%, the purge reduction calculation value fpg is reduced from the basic injection amount taupb of the intake passage injector 120 to the purge reduction calculation value fpg, so that the in-cylinder injection amount injector 110 The purge reduction calculation value fpg is not reflected in the basic fuel injection amount taudb. That is, as shown on the right side of FIG. 5 (B), when the in-cylinder injector 110 and the intake manifold injector 120 are performing injection division (0 <DI ratio r <1.0). In this case, the fuel correction amount associated with execution of the purge process based on the purge reduction calculation value fpg is reduced from the basic injection amount taupb of the intake manifold injector 120, and the basic fuel injection amount taudb of the in-cylinder injector 110 is not changed. .

  FIG. 6 compares the case where the purge process is being performed and the case where the purge process is not being performed. In the case where the purge process is being performed, the correction process for the fuel loss during the purge process according to the present invention is performed. And a correction process for the fuel loss when the purge process is executed by the comparative technique.

  As shown in FIG. 6, when the purge process is not executed, the final injection amounts of the in-cylinder injector 110 and the intake manifold injector 120 are respectively calculated according to the DI ratio r. In the case where the purge process is executed, for example, as shown as a comparative technique, the purge reduction calculated value fpg is set to the in-cylinder injector 110 (DI) and the intake manifold injector 120 (in accordance with the DI ratio r ′). Divided into PFI). That is, in the comparative technique, the purge reduction calculation value on the intake passage injector 120 side is calculated as fpg × (1−r ′), and the purge reduction calculation value on the in-cylinder injector 110 side is calculated as fpg × r ′. The

  On the other hand, in the present invention, the DI ratio r of the in-cylinder injector 110 is not changed regardless of whether or not the purge process is performed, and the basic fuel injection amount taupb of the intake passage injector 120 (PFI) is not changed. The fuel correction during the purge process is performed by subtracting the purge reduction amount fpg.

  In this way, the fuel injection amount in the in-cylinder injector does not change (does not decrease) in the case where there is a purge, and the injection hole temperature of the in-cylinder injector does not increase. Deposit accumulation can be prevented. Further, since the in-cylinder injector injects at a high pressure, the variation in the injection amount is larger than that of the intake passage injector that injects at a low pressure. However, the air-fuel ratio does not decrease the fuel injection amount from the in-cylinder injector. The learning value of control can be applied as it is. Further, since the fuel injection amount from the in-cylinder injector is not reduced to near the minimum fuel injection amount, it is large even in a region where there is no linearity of the relationship between the actual fuel injection amount and the fuel injection period in the vicinity of the minimum fuel injection amount. It is possible to avoid the occurrence of defects.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram of an engine system controlled by a control device according to an embodiment of the present invention. It is a figure showing the map which shows the injection division ratio of the injector for cylinder injection, and the injector for intake passage injection. It is a flowchart (the 1) which shows the control structure of the program performed by engine ECU which is a control apparatus which concerns on embodiment of this invention. It is a flowchart (the 2) which shows the control structure of the program performed by engine ECU which is a control apparatus which concerns on embodiment of this invention. It is a figure which shows the change of the fuel injection quantity at the time of purge processing execution in the case where it transfers to the injection division state from the fuel injection state by only the in-cylinder injector with the same load. It is a figure which shows the comparison of the fuel injection quantity at the time of purge processing execution.

Explanation of symbols

  10 engine, 20 intake manifold, 30 surge tank, 40 intake duct, 42 air flow meter, 50 air cleaner, 60 electric motor, 70 throttle valve, 80 exhaust manifold, 90 three-way catalytic converter, 100 accelerator pedal, 110 in-cylinder injector , 112 cylinder, 120 Injector injector, 130 Fuel distribution pipe, 140 Check valve, 150 High pressure fuel pump, 152 Electromagnetic spill valve, 160 Fuel distribution pipe (low pressure side), 170 Fuel pressure regulator, 180 Low pressure fuel pump, 190 fuel filter, 200 fuel tank, 300 engine ECU, 310 bidirectional bus, 320 ROM, 330 RAM, 340 CPU, 350 input port, 360 output port, 370, 39 , 410,430,450 A / D converter, 380 a water temperature sensor, 400 a fuel pressure sensor, 420 an air-fuel ratio sensor, 440 an accelerator opening sensor, 460 rpm sensor.

Claims (5)

Each cylinder is provided with a first fuel injection means for injecting fuel into the cylinder and a second fuel injection means for injecting fuel into the intake passage, and a purge process of fuel evaporative gas is executed A control device for an internal combustion engine,
When the rotational speed and load factor of the internal combustion engine are relatively small, the fuel injection amount of the first fuel injection means relative to the total fuel injection amount is larger than when the rotational speed and load factor are relatively large. Control means for controlling the fuel injection means so as to inject fuel in a shared manner between the first fuel injection means and the second fuel injection means so that the ratio is small ;
The fuel injection unit is controlled so that the correction of the fuel injection amount corresponding to the introduced purge fuel amount is shared between the first fuel injection unit and the second fuel injection unit when the purge process is executed. Purge control means for
In the region where the fuel injection is shared by the first fuel injection unit and the second fuel injection unit, the purge control unit determines the fuel injection amount of the first fuel injection unit relative to the total fuel supply amount. A control device for an internal combustion engine, including means for controlling the fuel injection means so as not to change the ratio.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the purge control means includes means for controlling so as not to change the fuel injection amount from the first fuel injection means.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the purge control means includes means for controlling only the fuel injection amount of the second fuel injection means.   The purge control means controls to inject the fuel injection amount calculated by subtracting the purge fuel amount from the basic fuel injection amount of the second fuel injection means from the second fuel injection means. The control apparatus for an internal combustion engine according to any one of claims 1 to 3, comprising means. The first fuel injection means is an in-cylinder injector,
The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the second fuel injection means is an intake passage injector.

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