JP5116872B1 - Control device for internal combustion engine - Google Patents

Abstract

An object of the present invention is to provide a control device for an internal combustion engine having a function of suppressing the deterioration of exhaust gas even when the intake state differs between two intake ports for each cylinder of the internal combustion engine.
An intake air amount and an intake air temperature of each intake port (5, 6) are determined based on output signals of intake air amount sensors (11, 12) and intake air temperature sensors (13, 14) disposed in intake air ports (5, 6) of an internal combustion engine. The ratio that is calculated and injected from the fuel injection valves 9 and 10 of the intake ports 5 and 6 with respect to the total fuel injection amount is the ratio of the intake temperature of the intake port on the low temperature side and the intake temperature of both intake ports 5 and 6. By setting accordingly, a good air-fuel mixture with little unevaporated fuel is formed for each intake port, so that deterioration of exhaust gas can be suppressed.
[Selection] Figure 3

Description

  The present invention relates to an internal combustion engine control device having two intake ports for each cylinder.

  Generally, for example, a premixed compression self-ignition internal combustion engine is known as an internal combustion engine having two intake ports for each cylinder and having different intake states between the intake ports. In a premixed compression self-ignition internal combustion engine, a pre-mixed air / fuel mixture is compressed by a piston to reach a self-ignition temperature, and combustion is simultaneously started at a plurality of locations in the combustion chamber. In a general spark ignition internal combustion engine, it is difficult to set the temperature of the air-fuel mixture to the self-ignition temperature by adiabatic compression. Therefore, the premixed compression self-ignition internal combustion engine has a higher compression ratio than the spark ignition internal combustion engine. As a result, the temperature rise due to adiabatic compression is increased, and the intake air temperature is raised by using EGR (Exhaust Gas Recirculation) or a heater, so that the mixture temperature reaches the self-ignition temperature. In this way, premixed compression self-ignition is realized by raising the temperature of the air-fuel mixture. However, since the entire air-fuel mixture burns at once, premixed compression self-ignition has a higher combustion speed than spark ignition. In particular, at a high load where the amount of fuel increases, more fuel burns at a time, so the combustion speed is high and noise and vibration are likely to occur. As a result, there is a limit in the operation region on the high load side.

  Therefore, in order to widen the upper limit on the high load side, there is a method of forming a layer of a high temperature mixture and a low temperature mixture in the combustion chamber. The aim is to ensure reliable ignition in the high temperature mixture layer and slow down the overall combustion rate by delaying combustion in the low temperature mixture layer. For example, in the control device for a premixed compression self-ignition engine disclosed in Patent Document 1, an air-fuel mixture containing high-temperature EGR is supplied to the combustion chamber from only one of the two intake ports, and from the other intake port. By supplying a mixture of low temperature fresh air to the combustion chamber, the degree of temperature non-uniformity in the combustion chamber is increased, and noise and vibration at high loads are suppressed.

JP 2002-256925 A

  However, in the control device for the premixed compression self-ignition engine disclosed in Patent Document 1, the intake air temperature in the combustion chamber is made non-uniform by making the intake air temperatures different at the two intake ports. The ease of vaporization of the fuel between the intake ports and the difference in the mixture formation associated therewith are not taken into consideration, and the same amount of fuel is injected at both intake ports. As a result, the intake port having a low intake temperature has a problem that the fuel is less vaporized than the intake port having a high intake temperature, and a large amount of non-evaporated fuel is contained, so that exhaust gas is deteriorated.

  The present invention has been made to solve the above-described problems, and has a function of suppressing exhaust gas deterioration even when the intake state differs between two intake ports for each cylinder of an internal combustion engine. It aims at providing the control apparatus of the internal combustion engine which has this.

In order to solve the above problems, an internal combustion engine control apparatus according to the present invention includes an intake state detection function for detecting an intake state at two intake ports provided for each cylinder, and fuel injected into each intake port. A fuel injection adjustment function for adjusting an injection timing and an injection amount of the fuel, and the fuel injection adjustment function obtains a ratio of fuel injected into each intake port with respect to a total fuel injection amount by the intake state detection function. It is characterized in that it is set according to the inhaled state.

  According to the control device for an internal combustion engine of the present invention, the ratio of the fuel injected to each intake port with respect to the total fuel injection amount is set according to the intake state of each intake port, whereby unevaporated fuel is generated for each intake port. Since a small and favorable air-fuel mixture is formed, the deterioration of exhaust gas can be suppressed.

It is a schematic block diagram of the internal combustion engine in the control apparatus of the internal combustion engine which concerns on this invention. It is sectional drawing of the combustion chamber part of the internal combustion engine cut | disconnected by the surface containing one of the two intake ports and exhaust ports in this invention. It is a block diagram which shows the control processing performed with the engine control unit (ECU) in this invention. 6 is a flowchart showing a processing procedure in a main control processing step in the first embodiment and the second embodiment. 4 is a flowchart showing a processing procedure in a fuel injection control processing step in the first embodiment. FIG. 3 is a diagram showing a basic fuel injection amount set based on the rotational speed and load of the internal combustion engine in the first embodiment. FIG. 3 is a diagram showing basic fuel injection timing set based on the rotational speed of the internal combustion engine in the first embodiment. 6 is a diagram showing a fuel injection amount ratio of a low-temperature side intake port set based on the intake air temperature in the first embodiment. FIG. FIG. 6 is a diagram showing a fuel injection timing advance amount of a low temperature side intake port set based on the intake air temperature in the first embodiment. 6 is a flowchart showing a processing procedure in a fuel injection control processing step in a second embodiment. 10 is a flowchart showing a processing procedure in a main control processing step in the third embodiment. 10 is a flowchart showing a processing procedure in a fuel injection control processing step in a third embodiment.

  Hereinafter, a control device for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram of an internal combustion engine in an internal combustion engine control apparatus according to the present invention, and FIG. 2 is a diagram of a combustion chamber portion of the internal combustion engine cut along a plane including one of two intake ports and an exhaust port. It is sectional drawing. A four-cycle internal combustion engine will be described as an example of the internal combustion engine. FIG. 3 is a block diagram showing a control process executed by the engine control unit (ECU).

As shown in FIGS. 1 and 2, the internal combustion engine according to the present invention includes an internal combustion engine body 1, a combustion chamber 2 of the internal combustion engine body 1, and a first intake port 5 and a second intake port in the combustion chamber 2. 6 is connected, and an intake pipe 22 is disposed upstream of both intake ports. The intake pipe 22 is provided with a throttle valve 23 for adjusting the amount of air supplied to the combustion chamber 2 and an intake pipe pressure sensor 24 for detecting the pressure of the intake pipe 22. From the pressure detection of the pressure sensor 24, the load of the internal combustion engine is calculated. The first intake port 5 and the second intake port 6 include a first intake air sensor 11 and a second intake air sensor 12 that detect the intake air amount, a first intake air temperature sensor 13 that detects the intake air temperature, and a second intake air vehicle. A temperature sensor 14 is attached to each intake port, and an atmospheric temperature sensor 27 for detecting the atmospheric temperature is attached in the vicinity of the intake pipe 22. Further, a first fuel injection valve 9 and a second fuel injection valve 10 for injecting fuel are arranged in the first intake port 5 and the second intake port 6 respectively, and the fuel injected in each intake port An air-fuel mixture is formed by the air supplied from the intake pipe 22 upstream of the intake port. The air-fuel mixture formed in each intake port is a first intake valve 3 disposed in the first intake port 5 that opens and closes both the intake ports 5 and 6 and the combustion chamber 2 and a second intake port 6 disposed in the second intake port 6. It is supplied to the combustion chamber 2 via the intake valve 4. On the other hand, two exhaust valves 7 for discharging burned burned gas are attached to the combustion chamber 2, and an exhaust pipe is connected via an exhaust port 8 disposed downstream of the exhaust valve 7 by opening the exhaust valve 7. 15 is discharged. The first intake port 5 and the second intake port 6 communicate with the exhaust pipe by the first EGR pipe 16 and the second EGR pipe 25, and the first EGR adjustment that adjusts the EGR flow rate in the first EGR pipe 16 and the second EGR pipe 25. A valve 17 and a second EGR adjustment valve 26 are arranged. ECU (engine control unit) 18 that controls actuators such as fuel injection valves 9 and 10, crank angle sensor 19 attached to the internal combustion engine body 1, cam angle sensor 20 attached to the internal combustion engine body 1, combustion The piston 21 is provided in the chamber 2 and introduces, compresses, burns, and discharges the air-fuel mixture. Although the internal combustion engine body 1 is configured as a multi-cylinder engine, only one cylinder of the internal combustion engine body 1 is shown in FIGS. 1 and 2.

Next, details of the operation of the internal combustion engine according to the present invention will be described.
First, the air whose air amount has been adjusted by the throttle valve 23 is supplied to the intake pipe 22, and is divided into two parts, the first intake port 5 and the second intake port 6, sent from the intake pipe 22. The intake air amount of the first intake port 5 and the second intake port 6 is detected by the first intake air amount sensor 11 and the second intake air amount sensor 12, and the first intake air temperature sensor 13 and the second intake air temperature sensor 14 are Intake air temperatures T1 and T2 are detected, respectively. In the first intake port 5 and the second intake port 6, the air and the fuel injected from the fuel injection valves 9 and 10 are mixed to form an air-fuel mixture. The air-fuel mixture formed by the intake ports 5 and 6 enters the combustion chamber 2 by the opening operation of the first intake valve 3 and the second intake valve 4 provided between the intake ports 5 and 6 and the combustion chamber 2. Supplied. The piston 21 reciprocates in the combustion chamber 2. When the piston 21 descends, the air-fuel mixture is introduced from the two intake valves 3 and 4 into the combustion chamber 2. The combustion pressure of the air-fuel mixture generated upon combustion is converted into kinetic energy, and the burned gas after combustion is discharged from the two exhaust valves 7.

  The crank angle sensor 19 attached to the internal combustion engine body 1 outputs a pulse signal every time the crankshaft rotates by a certain angle. From the crank angle sensor 19, for example, a rotation angle detection pulse is output every 10 ° of the crank rotation angle, and is used to calculate the rotation speed N of the internal combustion engine. Further, each time the camshaft rotates by the cam angle sensor 20 attached to the internal combustion engine body 1, a different pulse signal is output for each cylinder. The timing of the cylinder can be specified.

On the other hand, the burnt gas burned in the combustion chamber 2 is discharged to the exhaust pipe 15 through the exhaust port 8 disposed downstream of the exhaust valve 7 by the opening operation of the two exhaust valves 7. The EGR is recirculated through the first EGR pipe 16 communicated between the exhaust pipe 15 and the first intake port 5. The flow rate of EGR is adjusted by the first EGR adjustment valve 17. Similarly, the EGR is recirculated through the second EGR pipe 25 communicated between the exhaust pipe 15 and the second intake port 6. The flow rate of EGR is adjusted by the second EGR adjustment valve 26. By adjusting the flow rate of EGR flowing to the intake ports 5 and 6 by the EGR adjustment valves 17 and 26, the intake air temperatures T1 and T2 of the intake ports 5 and 6 can be adjusted. Specifically, if the opening degree of the EGR adjusting valves 17 and 26 is increased, the flow rate of EGR increases, and the intake air temperatures T1 and T2 at the intake ports 5 and 6 can be raised. By using this EGR to raise the intake air temperature, the temperature of the air-fuel mixture can reach the self-ignition temperature. Here, EGR is used as means for changing the intake air temperature, but other means such as a heater capable of changing the intake air temperature may be used.

  Here, an ECU (engine control unit) 18 provided in the passenger compartment or the like takes in the output signals of various sensors such as the intake air amount sensors 11 and 12 and the intake air temperature sensors 13 and 14, and based on the input signals, Arithmetic processing is executed, various actuator control signals are output based on the processing results, and the actuators such as the fuel injection valves 9 and 10 are controlled. The ECU 18 is a microcomputer system that executes fuel injection control for controlling the fuel injection amount and fuel injection timing.

  As shown in FIG. 3, the ECU 18 mainly includes an intake air amount detection function 30, an intake air temperature detection function 31, an intake air state detection function 34 including an atmospheric temperature detection function 32 and an intake heat quantity calculation function 33, and a fuel injection adjustment function. 35 is executed, and various arithmetic processes are executed based on the stored control program. In the intake air state detection function 34, the intake air temperature and the intake heat amount are calculated based on the output signals of the intake air sensors 11 and 12, the intake air temperature sensors 13 and 14, and the atmospheric temperature sensor 27. In the fuel injection adjustment function 35, the ratio of the fuel injected from the intake ports 5 and 6 with respect to the total fuel injection amount is set according to the intake air temperature and the intake heat amount, and the fuel injection valves 9 and 10 are controlled.

  Specifically, based on the output signals of the intake air amount sensors 11 and 12 disposed at the intake ports 5 and 6, the intake air amount detection functions 30 change the intake air amounts AQ1 and AQ2 at the intake ports 5 and 6, respectively. The intake air temperature detection function 31 calculates intake air temperatures T1 and T2 at the intake ports 5 and 6 based on the output signals of the intake air temperature sensors 13 and 14 disposed at the intake ports 5 and 6, respectively. Further, the intake heat quantity calculation function 33 takes into consideration the effects of the intake air amounts AQ1 and AQ2 at the intake ports 5 and 6, and the intake heat quantity from the intake air temperatures T1 and T2 and the intake air quantities AQ1 and AQ2 at the intake ports 5 and 6. CA1 and CA2 are calculated. In the fuel injection adjustment function 35, the ratio of the intake air temperature to the sum of the intake air temperature at the low-temperature side intake port and the intake air temperature at both intake ports 5 and 6, or the sum of the intake heat quantity at both intake ports 5 and 6 The ratio of the fuel injected from the fuel injection valves 9 and 10 of the intake ports 5 and 6 is set according to the intake heat quantity ratio.

  According to the intake state such as the intake air temperature and the intake heat quantity of each intake port 5, 6 which affects the fuel vaporization of both intake ports 5, 6, the amount of fuel injected into each intake port 5, 6 with respect to the total fuel injection amount Since the ratio is set, a good air-fuel mixture with little unevaporated fuel can be formed for each of the intake ports 5 and 6, and deterioration of exhaust gas can be suppressed.

Embodiment 1 FIG.
FIG. 4 is a flowchart showing a processing procedure in the main control processing step in the first embodiment, and FIG. 5 is a flowchart showing a processing procedure in the fuel injection control processing step. 6 is a basic fuel injection amount set based on the rotational speed and load of the internal combustion engine, FIG. 7 is a basic fuel injection timing set based on the rotational speed of the internal combustion engine, and FIG. 8 is set based on the intake air temperature. FIG. 9 shows the fuel injection timing advance amount of the low temperature side intake port set based on the intake air temperature.

  The operation of the control apparatus for the internal combustion engine of the first embodiment will be described. First, a basic fuel injection amount (total fuel injection amount) FQ supplied to the combustion chamber 2 from the rotational speed N and load L of the internal combustion engine is calculated. Ratio of fuel injected from the fuel injection valves 9 and 10 to each intake port 5 and 6 with respect to the basic fuel injection amount FQ according to the intake temperature of the low-temperature side intake port among the two intake ports 5 and 6 Is set. If the intake temperature on the low temperature side is equal to or lower than the predetermined temperature, the fuel injection to the intake port on the low temperature side is stopped. Further, the fuel injection timing at which fuel is injected from the fuel injection valve arranged in the low temperature side intake port is set according to the intake air temperature of the low temperature side intake port. The fuel injection timing is set earlier as the fuel vaporization temperature becomes lower. Since the fuel injection amounts FQ1, FQ2 and the fuel injection timings FT1, FT2 supplied to both the intake ports 5, 6 are set according to the intake temperature on the low temperature side where the fuel is hard to vaporize, the formation of the air-fuel mixture is extremely The deterioration of exhaust gas can be suppressed.

  Next, a processing procedure in the control device for the internal combustion engine executed by the ECU 18 will be described with reference to the flowcharts of FIGS. 4 and 5. In the main control processing step shown in FIG. 4, for example, when the present embodiment is applied to a four-cylinder internal combustion engine, it is executed for the cylinder corresponding to every crank angle of 180 degrees. First, the intake air temperatures T1 and T2 of the first intake port 5 and the second intake port 6 are detected (step S101). Next, a fuel injection control process corresponding to the intake air temperatures T1 and T2 is executed (step S102). The contents of the fuel injection control process are shown in the flowchart of the fuel injection control process in FIG.

  In the fuel injection control processing step shown in FIG. 5, based on the relationship between the rotational speed N of the internal combustion engine and the load L, the operating state is referred to by referring to a map (FIG. 6) of the basic fuel injection amount FQ set in advance through experiments. The basic fuel injection amount FQ according to the above is calculated (step S201). Also, based on the relationship between the rotational speed N of the internal combustion engine and the basic fuel injection timing FT, the basic fuel injection timing FTb is calculated with reference to a map (FIG. 7) of the basic fuel injection timing FT set in advance by experiments. (Step S202).

  Subsequently, the intake air temperature T1 of the first intake port 5 and the intake air temperature T2 of the second intake port 6 are compared (step S203). If the intake air temperature T1 of the first intake port 5 is lower, it is determined whether the intake air temperature T1 of the first intake port 5 is lower than a predetermined temperature TL (step S204). Here, the predetermined temperature TL has a low intake air temperature and the fuel is difficult to vaporize, and therefore, the temperature at which the formation of the air-fuel mixture is extremely bad and the exhaust gas deteriorates is obtained in advance from experimental results, and set to 0 ° C., for example. Keep it. If the intake air temperature T1 of the first intake port 5 is lower than the predetermined temperature TL, the intake air temperature T2 of the second intake port 6 is compared with the predetermined temperature TH (step S205). Here, as the predetermined temperature TH, a temperature at which the intake air temperature is high, the mixture is well formed and the exhaust gas is not deteriorated is obtained in advance from experimental results, and is set to 20 ° C., for example. If it is determined that the intake air temperature T2 of the second intake port 6 is higher than the predetermined temperature TH and the mixture formation of the second intake port 6 is good, the fuel amount FQ1 injected into the first intake port 5 is set to 0. The fuel amount FQ2 injected into the second intake port 6 is set as the total amount FQ of the basic fuel injection amount (step S206). Thereafter, the flow returns to the flowchart of the main control processing step in FIG.

On the other hand, in step S204, the intake air temperature T1 of the first intake port 5 serving as the low temperature side intake port is higher than the predetermined temperature TL, and in the intake state in which the formation of the air-fuel mixture is not extremely deteriorated, In the intake state where the intake temperature T2 of the second intake port 6 serving as the intake port is lower than the predetermined temperature TH and the fuel vaporization is not promoted so much, the intake air of the first intake port 5 which is the intake port having a low intake temperature. According to the temperature T1, the fuel injection amount ratio FR (T1) of the fuel injected into the intake ports 5 and 6 is calculated with reference to FIG. 8 (step S207). Subsequently, the fuel amount FQ1 of the first intake port 5 and the fuel amount FQ2 of the second intake port 6 are calculated from the basic fuel injection amount FQ and the fuel injection amount ratio FR (step S208). Formulas 1 and 2 show formulas for calculating the fuel amounts FQ1 and FQ2 of the intake ports 5 and 6, respectively.
First intake port fuel amount FQ1 = FQ * FR (1)
Second intake port fuel amount FQ2 = FQ * (1-FR) (2)
Therefore, as the intake air temperature T1 of the first intake port 5 is lower, the fuel amount FQ1 injected into the first intake port 5 with respect to the basic fuel injection amount FQ is the fuel injected into the second intake port 6 on the higher temperature side. It is set to be smaller than the amount FQ2. By reducing the fuel injection amount FQ1 of the first intake port 5 on the low temperature side, which makes it difficult for the fuel to vaporize and the mixture formation tends to deteriorate, the deterioration of the exhaust gas can be suppressed.

In order to advance the fuel injection timing FT1 at which fuel is injected into the first intake port 5, referring to FIG. 9, the fuel injection timing advance amount FT ( T1) is calculated (step S209). Thus, the basic fuel injection timing FTb is corrected by the fuel injection timing advance amount FT (T1), and the fuel injection timing FT1 at which fuel is injected into the first intake port 5 where the intake air temperature is low is set (step S210). ). Formula 3 shows a formula for calculating the fuel injection timing FT1 of the first intake port 5.
Fuel injection timing FT1 = Basic injection timing FTb−Fuel injection timing advance amount FT (T1) (3)
It should be noted that the fuel injection timing FT2 of the second intake port 6 at which the intake air temperature is higher is kept at the basic injection timing FTb. Advancing the fuel injection timing FT1 of the first intake port 5 at which the intake air temperature is on the low temperature side provides a time margin until the fuel is supplied to the combustion chamber 2 and allows more fuel to be vaporized, thus mixing. The formation of gas is improved and the deterioration of exhaust gas can be suppressed. Thereafter, the flow returns to the flowchart of the main control processing step in FIG.

  If it is determined in step S203 that the intake temperature T2 of the second intake port 6 is lower than the intake temperature T1 of the first intake port 5, the process in the first intake port 5 in step S204. Similarly, it is determined whether the intake temperature T2 of the second intake port 6 is lower than the predetermined temperature TL (step S211). When the intake temperature T2 of the second intake port 6 is lower than the predetermined temperature TL, the intake temperature T1 of the first intake port 5 is compared with the predetermined temperature TH (step S212). When the intake air temperature T1 of the first intake port 5 is higher than the predetermined temperature TH, the fuel amount FQ2 injected into the second intake port 6 is set to 0, and the fuel amount FQ1 injected into the first intake port 5 is set to 0. The total amount FQ of the basic fuel injection amount is set (step S213). Thereafter, the flow returns to the flowchart of the main control processing step in FIG.

In step S211, when the intake temperature T2 of the second intake port 6 serving as the low temperature side intake port is higher than the predetermined temperature TL, or in step S212, the intake air of the second intake port 6 serving as the high temperature side intake port. When the temperature T2 is lower than the predetermined temperature TH, the fuel injection amount of the fuel injected into the intake ports 5 and 6 according to the intake temperature T2 of the second intake port 6 that is an intake port having a low intake temperature. The ratio FR (T2) is calculated with reference to FIG. 8 (step S214). Subsequently, the fuel amount FQ1 of the first intake port 5 and the fuel amount FQ2 of the second intake port 6 are calculated from the basic fuel injection amount FQ and the fuel injection amount ratio FR (step S215). Equations 4 and 5 show equations for obtaining the fuel amounts FQ1 and FQ2 of the intake ports 5 and 6, respectively.
First intake port fuel amount FQ1 = FQ * (1-FR) (4)
Second intake port fuel amount FQ2 = FQ * FR (5)
Accordingly, as the intake air temperature T2 of the second intake port 6 is lower, the fuel amount FQ2 injected into the second intake port 6 with respect to the basic fuel injection amount FQ is the fuel injected into the first intake port 5 on the higher temperature side. It is set to be smaller than the amount FQ1. By reducing the fuel injection amount FQ2 of the second intake port 6 on the low temperature side, which makes it difficult for the fuel to vaporize and the mixture formation tends to deteriorate, the deterioration of the exhaust gas can be suppressed.

In order to advance the fuel injection timing FT2 at which fuel is injected into the second intake port 6, referring to FIG. 9, the fuel injection timing advance amount FT ( T2) is calculated (step S216). Thus, the basic fuel injection timing FTb is corrected by the fuel injection timing advance amount FT (T2), and the fuel injection timing FT2 at which fuel is injected into the second intake port 6 where the intake air temperature is low is set (step S210). ). Formula 6 shows a formula for calculating the fuel injection timing FT2 of the second intake port 6.
Fuel injection timing FT2 = Basic injection timing FTb−Fuel injection timing advance amount FT (T2) (6)
It should be noted that the fuel injection timing FT1 of the first intake port 5 at which the intake air temperature is higher is kept at the basic fuel injection timing FTb. Advancing the fuel injection timing FT2 of the second intake port 6 at which the intake air temperature is on the low temperature side provides a time margin until the fuel is supplied to the combustion chamber 2 and allows more fuel to be vaporized, so mixing The formation of gas is improved and the deterioration of exhaust gas can be suppressed. Thereafter, the flow returns to the flowchart of the main control processing step in FIG.

  Thus, according to the control apparatus for an internal combustion engine according to the first embodiment, the ratio of the fuel injected into each intake port is small on the low temperature side according to the low temperature side intake temperature of the two intake ports, and the high temperature Since the fuel is set to be increased, the amount of non-evaporated fuel is reduced even in the intake port on the low temperature side, so that the formation of the air-fuel mixture is not deteriorated. By setting the fuel injection timing to the advance side, it is possible to expect a remarkable effect that the deterioration of exhaust gas can be suppressed by securing the time for forming a good air-fuel mixture.

Embodiment 2. FIG.
FIG. 10 is a flowchart showing a processing procedure in the fuel injection control processing step in the second embodiment. In the first embodiment, the ratio of the fuel injected into each intake port with respect to the basic fuel injection amount (total fuel injection amount) is set according to the intake air temperature of the low-temperature intake port. In form 2, the ratio of the fuel injected into each intake port is set in accordance with the ratio of the intake temperature of each intake port to the total intake temperature of both intake ports. The flowchart showing the processing procedure in the main control processing step is the same as that in FIG.

  The operation of the control apparatus for an internal combustion engine according to the second embodiment will be described with reference to a flowchart showing a processing procedure in the fuel injection control processing step of FIG. Since the contents other than the method for setting the ratio of the fuel injected into the intake ports 5 and 6 are the same as those in the first embodiment, the description thereof will be omitted.

  In the fuel injection control processing step shown in FIG. 10, based on the relationship between the rotational speed N of the internal combustion engine and the load L, the operating state is referred to by referring to a map (FIG. 6) of the basic fuel injection amount FQ set in advance by experiments. The basic fuel injection amount FQ according to the above is calculated (step S301). Also, based on the relationship between the rotational speed N of the internal combustion engine and the basic fuel injection timing FT, the basic fuel injection timing FTb is calculated with reference to a map (FIG. 7) of the basic fuel injection timing FT set in advance by experiments. (Step S302).

  Next, in steps S303 to S305 and steps S310 to S311, the intake state of each intake port is determined, the intake air temperature of the low-temperature side intake port is lower than the predetermined temperature TL (steps S304 and S310), and the high-temperature side If the intake air temperature of the intake port is higher than the predetermined temperature TH (steps S305 and S311), the fuel injection amount to the low temperature side intake port is set to 0, and the fuel amount injected to the high temperature side intake port is basically The total fuel injection amount FQ is set (steps S306 and S312) (see equations 1 and 2). Thereafter, the flow returns to the flowchart of the main control processing step in FIG.

On the other hand, when the intake states of the intake ports 5 and 6 are other than the above conditions, the fuel amounts FQ1 and FQ2 injected into the intake ports 5 and 6 with respect to the basic fuel injection amount FQ are It is set according to the ratio of the intake air temperatures T1 and T2 (steps S307 and S313). Formulas 7 and 8 show formulas for calculating the fuel amounts FQ1 and FQ2 of the intake ports 5 and 6, respectively.
First intake port fuel amount FQ1 = FQ * T1 / (T1 + T2) (7)
Second intake port fuel amount FQ2 = FQ * T2 / (T1 + T2) (8)

Further, in order to advance the timing at which the fuel of the intake port whose intake air temperature is low in the intake ports 5 and 6 is advanced, the fuel injection timing advance is made according to the intake temperatures T1 and T2 of the intake port on the low temperature side. The quantity FT (T1) or FT (T2) is calculated (steps S308 and S314). As a result, the basic fuel injection timing FTb becomes the fuel injection timing advance amount FT (T1) or FT.
The fuel injection timing FT1 or FT2 at which the fuel is injected into the intake port having a low intake temperature and corrected at (T2) is set (steps S309 and S315). The process of calculating these fuel injection timings FT1 or FT2 is the same as the processes of steps S209 and S210 and steps S215 and S217 of the first embodiment, and the fuel injection timing advance amount FT (T1) or FT ( The formula for calculating T2) is the same as Formula 3 or Formula 6. Note that the fuel injection timing of the intake port at which the intake air temperature is higher is kept at the basic fuel injection timing FTb. Thereafter, the flow returns to the flowchart of the main control processing step in FIG.

  As described above, according to the control apparatus for an internal combustion engine according to the second embodiment, the fuel injected into each intake port according to the ratio of the intake air temperature of each port to the total intake air temperature at the two intake ports. Is set so that the low-temperature side is small and the high-temperature side is large, so that, as in the first embodiment, the amount of unevaporated fuel also decreases in the intake port on the low-temperature side, which deteriorates the formation of the air-fuel mixture. In addition, the fuel injection timing on the low temperature side is set to the advance side in accordance with the intake air temperature on the low temperature side, so that the time required to form a good air-fuel mixture is secured, thereby suppressing the deterioration of exhaust gas. The remarkable effect of being able to do it can be expected.

Embodiment 3 FIG.
FIG. 11 is a flowchart showing a processing procedure in the main control process in the third embodiment, and FIG. 12 is a flowchart showing a processing procedure in the fuel injection control process. In the second embodiment, the ratio of the fuel injected into each intake port with respect to the basic fuel injection amount (total fuel injection amount) is set according to the ratio of the intake temperature of each port to the total intake air temperature at both intake ports. On the other hand, in the third embodiment, the ratio of the fuel injected into each intake port is set according to the intake heat amount of each intake port in consideration of the intake amount of each intake port.

  The operation of the control apparatus for an internal combustion engine according to the third embodiment will be described with reference to the flowchart in the main control processing step in FIG. 11 and the flowchart showing the processing procedure in the fuel injection control processing in FIG.

  In the main control process shown in FIG. 11, the intake air temperatures T1 and T2 of the first intake port 5 and the second intake port 6 are detected (step S401). Next, the intake air amounts AQ1 and AQ2 of the first intake port 5 and the second intake port 6 are detected (step S402), and the atmospheric temperature Ta is detected (step S403). Subsequently, a fuel injection control process corresponding to the intake heat quantity is executed (step S404). The contents of the fuel injection control process are shown in the flowchart of the fuel injection control process in FIG.

Next, in the fuel injection control processing step shown in FIG. 12, as in the first embodiment, a map of the basic fuel injection amount FQ set in advance in an experiment based on the relationship between the rotational speed N and the load L of the internal combustion engine. Referring to (FIG. 6), basic fuel injection amount FQ corresponding to the operating state is calculated (step S501). Also, based on the relationship between the rotational speed N of the internal combustion engine and the basic fuel injection timing FT, the basic fuel injection timing FTb is calculated with reference to a map (FIG. 7) of the basic fuel injection timing FT set in advance by experiments. (Step S502). Further, the intake heat amounts CA1 and CA2 of the intake ports 5 and 6 are calculated from the atmospheric temperature Ta, the intake air temperatures T1 and T2 of the first intake port 5 and the second intake port 6 and the intake air amounts AQ1 and AQ2. (Step S503). Formulas 9 and 10 show formulas for calculating the intake heat amounts CA1 and CA2 of the intake ports 5 and 6, respectively.
Heat quantity CA1 of the first intake port = specific heat (0.24) * AQ1 * (T1-Ta) (9)
Heat quantity CA2 of second intake port = specific heat (0.24) * AQ2 * (T2-Ta) (10)

Subsequently, the intake heat amount CA1 of the first intake port 5 and the intake heat amount CA2 of the second intake port 6 are compared (step S504). If the intake heat amount CA1 of the first intake port 5 is lower, it is determined whether the intake heat amount CA1 of the first intake port 5 is lower than the predetermined heat amount CAL (step S505). Here, the predetermined calorie | heat amount CAL sets and calculates | requires beforehand the calorie | heat amount which exhaust gas deteriorates from an experimental result since there is much unevaporated fuel and formation of air-fuel | gaseous mixture is bad. When the intake heat amount CA1 of the first intake port 5 is lower than the predetermined heat amount CAL, the intake heat amount CA2 of the second intake port 6 and the predetermined heat amount CAH are compared (step S506). Here, the predetermined heat amount CAH is set by obtaining in advance experimental results a heat amount in which the heat amount of the intake air in the intake port on the high temperature side is high, the mixture is well formed, and the exhaust gas does not deteriorate. If the intake heat amount CA2 of the second intake port 6 is higher than the predetermined heat amount CAH and it is determined that the mixture of the second intake port 6 is well formed, the fuel amount FQ1 injected into the first intake port 5 is set to zero. The fuel amount FQ2 injected into the second intake port 6 is set as the total basic fuel injection amount FQ (step S507). Thereafter, the process returns to the flowchart of the main control processing step in FIG.

On the other hand, when the intake heat quantity state of the intake ports 5 and 6 is other than the above condition, the ratio of the fuel amounts FQ1 and FQ2 injected into the intake ports 5 and 6 with respect to the basic fuel injection amount FQ is the both intake ports. It is set according to the ratio of each intake heat quantity CA1, CA2 to the total intake heat quantity at 5, 6 (step S508). Formulas 11 and 12 show formulas for calculating the fuel amounts FQ1 and FQ2 of the intake ports 5 and 6, respectively.
First intake port fuel amount FQ1 = FQ * CA1 / (CA1 + CA2) (11)
Second intake port fuel amount FQ2 = FQ * CA2 / (CA1 + CA2) (12)

  In order to improve the formation of the air-fuel mixture, the calculation of the fuel injection timing advance amount FT (T1) (step 509) and the setting of the fuel injection timing FT1 (step S510) are described in step S209 of the first embodiment. , S210, and the description is omitted. Thereafter, the process returns to the flowchart of the main control processing step in FIG.

  If it is determined in step S504 that the intake heat amount CA2 of the second intake port 6 is lower than the intake heat amount CA1 of the first intake port 5, the process in the first intake port 5 of step S505 is performed. Similarly, it is determined whether or not the intake heat amount CA2 of the second intake port 6 is lower than the predetermined heat amount CAL (step S511). If the intake heat amount CA2 of the second intake port 6 is lower than the predetermined heat amount CAL, the intake heat amount CA1 of the first intake port 5 and the predetermined heat amount CAH are compared (step S512). When the intake heat amount CA1 of the first intake port 5 is higher than the predetermined heat amount CAH, the fuel amount FQ2 injected into the second intake port 6 is set to 0, and the fuel amount FQ1 injected into the first intake port 5 is set to 0. The total amount FQ of the basic fuel injection amount is set (step S513). Thereafter, the process returns to the flowchart of the main control processing step in FIG.

  In step S511, if the intake heat quantity CA2 of the second intake port 6 on the low heat quantity side is equal to or greater than the predetermined heat quantity CAL and the intake port is in an intake state where the formation of air-fuel mixture is improved, or in step S512, When the intake heat amount CA1 of the first intake port 5 on the high heat amount side is lower than the predetermined heat amount CAH, the fuel amount FQ1 of the first intake port 5 and the fuel amount FQ2 of the second intake port 6 are the basic fuel injection amount FQ. And the ratio of each intake heat quantity CA1, CA2 to the total intake heat quantity at both intake ports 5, 6 (step S514). The equations for calculating the fuel amount FQ1 of the first intake port 5 and the fuel amount FQ2 of the second intake port 6 are the same as Equations 11 and 12.

  In order to improve the formation of the air-fuel mixture, the calculation of the fuel injection timing advance amount FT (T2) (step 515) and the setting of the fuel injection timing FT2 (step S516) are described in step S216 of the first embodiment. , And the contents are the same as those in S217, and the description thereof will be omitted. Thereafter, the process returns to the flowchart of the main control processing step in FIG.

Thus, according to the control apparatus for an internal combustion engine according to the third embodiment, the intake heat quantity of each port with respect to the total intake heat quantity at each intake port in consideration of the intake temperature and intake quantity of the two intake ports. The ratio of the fuel injected into each intake port is set so that the low heat quantity side is small and the high heat quantity side is large, so the intake air in both intake ports is affected by the influence of intake air flow and intake air temperature. Even when the amount is different, the amount of unevaporated fuel is reduced, and the formation of the air-fuel mixture is not deteriorated.Furthermore, the fuel injection timing on the low heat amount side is set to the advance side according to the intake temperature on the low heat amount side. As a result, it is possible to expect a remarkable effect that the deterioration of the exhaust gas can be suppressed by securing the time for forming a good air-fuel mixture.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  Moreover, in the figure, the same code | symbol shows the same or an equivalent part.

Reference Signs List 1 internal combustion engine body 2 combustion chamber 3 first intake valve 4 second intake valve 5 first intake port 6 second intake port 9 first fuel injection valve 10 second fuel injection valve 11 first intake amount sensor 12 second intake amount Sensor 13 First intake air temperature sensor 14 Second intake air temperature sensor 18 ECU (Engine Control Unit)
24 Intake pipe pressure sensor 27 Atmospheric temperature sensor 30 Intake air amount detection function 31 Intake air temperature detection function 32 Atmospheric temperature detection function 33 Intake heat amount calculation function 34 Intake state detection function 35 Fuel injection adjustment function

Claims (10)

An intake state detection function for detecting an intake state at two intake ports provided for each cylinder, and a fuel injection adjustment function for adjusting an injection timing and an injection amount of fuel injected into each intake port,
The control device for an internal combustion engine, wherein the fuel injection adjustment function sets a ratio of fuel injected into each intake port with respect to a total fuel injection amount according to an intake state obtained by the intake state detection function .   2. The control apparatus for an internal combustion engine according to claim 1, wherein the intake air state detection function detects an intake air temperature at each intake port.   The fuel injection adjustment function is characterized in that if the intake air temperature at the low-temperature side intake port of the two intake ports is equal to or lower than a predetermined temperature, the fuel injection amount to the low-temperature side intake port is set to zero. The control device for an internal combustion engine according to claim 2.   The fuel injection adjustment function sets a ratio of fuel injected into each intake port with respect to the total fuel injection amount according to an intake air temperature at a low-temperature intake port of the two intake ports. The control device for an internal combustion engine according to claim 2.   The fuel injection adjustment function sets a ratio of fuel injected into each intake port with respect to the total fuel injection amount according to a ratio of intake temperature of each port to the total intake temperature at the two intake ports. The control apparatus for an internal combustion engine according to claim 2, wherein the control apparatus is an internal combustion engine.   The fuel injection adjustment function sets an injection timing of the fuel to the low temperature side intake port according to an intake air temperature at a low temperature side intake port of the two intake ports. The control apparatus for an internal combustion engine according to claim 4 or 5.   The intake state detection function detects an air temperature, an intake air temperature and an intake air amount at each intake port, and calculates an intake heat amount of each intake port from the detected air temperature, intake air temperature and intake air amount. The control apparatus for an internal combustion engine according to claim 1, wherein the control apparatus is an engine.   The fuel injection adjustment function sets the fuel injection amount to the low heat quantity intake port to 0 if the intake heat quantity at the low heat quantity intake port of the two intake ports is equal to or less than a predetermined heat quantity. 8. The control apparatus for an internal combustion engine according to claim 7, wherein the control apparatus is an internal combustion engine.   The fuel injection adjustment function sets a ratio of fuel injected into each intake port with respect to the total fuel injection amount according to a ratio of intake heat amount of each port with respect to a total intake heat amount at the two intake ports. 8. The control apparatus for an internal combustion engine according to claim 7, wherein the control apparatus is an internal combustion engine.   The fuel injection adjustment function sets an injection timing of the fuel to the low heat quantity intake port according to an intake heat quantity of a low temperature intake port among the two intake ports. The control apparatus for an internal combustion engine according to claim 9.

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