JP4807327B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device that controls the operating state of an internal combustion engine, and more particularly, to a control device for an internal combustion engine that can operate with a fuel in which gasoline and alcohol are mixed.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2006-214415), an internal combustion engine capable of operating with a fuel in which gasoline and alcohol are mixed is known. Here, the conventional internal combustion engine includes a port injection valve that injects fuel toward the intake port of the combustion chamber, and a cylinder injection valve that directly injects fuel into the combustion chamber.

  Further, the control device for controlling the internal combustion engine, for example, in a specific region of the operation region determined according to the engine speed and the load state of the internal combustion engine, the fuel is supplied by both the port injection valve and the in-cylinder injection valve. It is set as a spraying area for injection. And in the injection division area, it is set as the structure which enlarges the injection ratio of the fuel injected from a cylinder injection valve, so that the alcohol concentration in fuel becomes high. That is, in the prior art, it is assumed that a fuel with a high alcohol concentration can quickly vaporize the fuel and obtain a good mixture even when in-cylinder injection is performed with a short time from injection to combustion. .

  Further, as another conventional technique, for example, as disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 3-61642), either a port injection valve or a cylinder injection valve is selected depending on the operating state of the internal combustion engine. An internal combustion engine configured to operate one of the injection valves is also known.

JP 2006-214415 A Japanese Patent Laid-Open No. 3-61642

  In the prior art of Patent Document 1 described above, the higher the alcohol concentration in the fuel, the higher the injection ratio of the in-cylinder injection valve. However, the fuel injected into the cylinder tends to form a heterogeneous mixture because the time until combustion is short. For this reason, as a method of fuel injection control, there is also an idea that among the entire operation regions of the internal combustion engine, the region in which the port injection valve operates is set as wide as possible to stabilize the operation performance.

  However, if the operating region of the port injection valve is simply set wide, for example, in the region where the combustion temperature is high, the tip temperature of the in-cylinder injection valve rises, and deposits and the like are induced. The in-cylinder injection valve is mainly used in a region where it is desired to increase the output of the internal combustion engine. In such a region, if the port injection valve is operated, a sufficient output may not be obtained. For this reason, in the prior art of patent document 1, there exists a problem that it is difficult to set the operating area | region of a port injection valve widely.

  On the other hand, in the prior art of Patent Document 2, one of the port injection valve and the in-cylinder injection valve is operated according to the operating state of the internal combustion engine. However, depending on the operating range of the internal combustion engine, there is a problem that even if one of the injection valves is operated, the operating performance and output requirements cannot be sufficiently satisfied.

  The present invention has been made to solve the above-described problems, and is capable of expanding the operating range of the port injection valve while satisfying the demand for the output of the internal combustion engine, etc., and driving performance such as fuel consumption and torque fluctuation. An object of the present invention is to provide a control device for an internal combustion engine capable of improving the engine.

A first invention is a port injection valve that injects fuel toward an intake port of an internal combustion engine;
An in-cylinder injection valve for injecting fuel into the cylinder of the internal combustion engine;
Alcohol concentration detection means for detecting the alcohol concentration in the fuel;
Of the operating range determined according to the engine speed and the load state of the internal combustion engine, the range of the injection divided region where both the port injection valve and the in-cylinder injection valve inject fuel is determined according to the alcohol concentration. A spray dividing region variable means for setting the variable;
It is characterized by providing.

  According to the second invention, the spray area changing means is configured to expand the spray area as the alcohol concentration increases.

  According to a third aspect of the invention, the spray region changing means is configured to provide the spray region along the fully open region of the operation region when the alcohol concentration is higher than the determination concentration.

  According to a fourth aspect of the present invention, the temperature detection means for detecting the temperature of the internal combustion engine, and the port injection area in which only the port injection valve injects fuel in the operation area is expanded as the temperature detected by the temperature detection means becomes lower. And a port injection region varying means.

A fifth aspect of the invention is a port injection valve that injects fuel toward an intake port of an internal combustion engine;
An in-cylinder injection valve for injecting fuel into the cylinder of the internal combustion engine;
Temperature detecting means for detecting the temperature of the internal combustion engine;
Port injection region variable means for expanding a port injection region in which only the port injection valve injects fuel among operating regions determined according to the engine speed and load state of the internal combustion engine as the temperature of the internal combustion engine decreases. When,
It is characterized by providing.

  According to the sixth invention, the port injection region variable means is configured to expand the port injection region as the concentration of alcohol contained in the fuel increases.

  According to the first aspect of the present invention, the spray dividing region varying means is configured to select a spray dividing region for injecting fuel from the port injection valve and the in-cylinder injection valve in the entire operation region of the internal combustion engine according to the alcohol concentration in the fuel. Can be set variable. Here, when the alcohol concentration is high, the causative component of the deposit contained in the gasoline is diluted, so that it is difficult for the in-cylinder injection valve to deposit.

  For this reason, the fuel injection for cooling the front-end | tip part of a cylinder injection valve can be reduced moderately. Then, this reduced amount can be injected from the port injection valve. In addition, since the fuel with a high alcohol concentration has a lower calorific value than gasoline, the total fuel injection amount increases to compensate for this. For this reason, it becomes possible to share a part of fuel injection amount of the cylinder injection valve with the port injection valve. In particular, the port injection valve can be operated together in a region where the fuel injection amount is insufficient with only the cylinder injection valve.

  Thus, when the alcohol concentration is high, the port injection valve can be operated together, for example, in a region where only the in-cylinder injection valve has been operated conventionally. That is, since the operating area of the port injection valve can be expanded as necessary, the range of the spraying area where both the injection valves operate can be appropriately set according to the alcohol concentration. As a result, in a wide range of the operation range, for example, the in-cylinder injection valve can satisfy the demand for the output of the internal combustion engine, etc., and a homogeneous air-fuel mixture can be formed by the port injection valve. Can be improved.

  According to the second aspect of the invention, when the alcohol concentration in the fuel is high, the fuel injection amount of the in-cylinder injection valve is reduced by an amount that makes it difficult for the deposit to accumulate, and the port injection valve is operated together by this reduction amount. Can be made. Further, since the overall fuel injection amount increases, the port injection valve can be operated together without reducing the fuel injection amount of the in-cylinder injection valve depending on the operation region. Therefore, the spray area changing means can expand the range of the spray area as the alcohol concentration increases. Thereby, fuel consumption and torque fluctuation can be improved while protecting the in-cylinder injection valve from deposits.

  According to the third invention, when the alcohol concentration in the fuel is high, the fuel injection amount increases. For this reason, in the fully open region that requires a large amount of fuel injection, for example, the variable injection region variable means can compensate for the fuel injection amount that is insufficient with only the in-cylinder injection valve, for example, by the port injection valve. An appropriate amount of fuel injection can be performed. Therefore, even when a high alcohol concentration fuel is used, the operation in the fully open region can be stably performed.

  Further, when designing the internal combustion engine, for example, it is not necessary to set the maximum injection amount or the like of each injection valve excessively large with reference to the amount of fuel required in the fully open region when the alcohol concentration is high. For this reason, it is possible to appropriately design the port injection valve and the in-cylinder injection valve, respectively, and it is possible to suppress an increase in cost.

  According to the fourth aspect of the invention, when the internal combustion engine is at a low temperature, the injected fuel is difficult to vaporize, so the air-fuel mixture becomes inhomogeneous and the combustion state tends to fluctuate. In this case, the port injection region variable means can expand the port injection region from, for example, a low rotation / low load operation region to a middle rotation / middle load operation region. Therefore, even when the internal combustion engine is operated at a low temperature, it is possible to improve driving performance such as fuel consumption and torque fluctuation in a wide range of the operating range. In addition, by expanding the port injection region, it is possible to reduce the frequency of opening and closing the in-cylinder injection valve that performs fuel injection at a high pressure. As a result, it is possible to reduce a relatively large operating noise (noise) when the cylinder injection valve operates.

  According to the fifth aspect, it is possible to obtain the same operational effects as in the case of the fourth aspect. Therefore, even when the internal combustion engine is operated at a low temperature, it is possible to improve driving performance such as fuel consumption and torque fluctuation in a wide range of the operating range. Moreover, noise during operation can be reduced.

  According to the sixth aspect of the invention, there are few causative components of deposits in the fuel having a high alcohol concentration. For this reason, when the alcohol concentration is high, the port injection region variable means can stop the in-cylinder injection valve and operate only the port injection valve in a relatively wide operation region. Thereby, fuel consumption and torque fluctuation can be improved while protecting the in-cylinder injection valve from deposits.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
The first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram for explaining a system configuration according to the first embodiment. An internal combustion engine 10 shown in FIG. 1 is configured as a dual injection internal combustion engine for an FFV (Flexible Fuel Vehicle) operated by a fuel in which gasoline and alcohol are mixed at an arbitrary ratio.

  Here, the internal combustion engine 10 includes one or a plurality of cylinders 12 (in this embodiment, four cylinders are exemplified). An intake passage 14 including an intake manifold is connected to the intake port 12a of each cylinder 12. The intake passage 14 sucks air (intake air) into the individual cylinders 12. Further, an exhaust passage is connected to an exhaust port (not shown) of each cylinder 12.

  The intake passage 14 of each cylinder 12 is provided with a port injection valve 16 for injecting fuel toward the intake port 12a. Further, each cylinder 12 is provided with an in-cylinder injection valve 18 that directly injects fuel into the respective combustion chambers. In this case, the in-cylinder injection valve 18 often injects a relatively large amount of fuel when the internal combustion engine 10 is operated at a high rotation speed or a high load state. For this reason, the in-cylinder injection valve 18 is configured by using a large flow rate type injection valve, and the maximum fuel injection amount is set larger than that of the port injection valve 16.

  Next, a fuel supply system to each of the injection valves 16 and 18 will be described. First, the internal combustion engine 10 is provided with a fuel tank 20 in which gasoline and alcohol are supplied at an arbitrary mixing ratio. A low pressure fuel pipe 22 is connected between the fuel tank 20 and each port injection valve 16. A low pressure pump 24 is provided in the middle of the low pressure fuel pipe 22. Thereby, the low pressure pump 24 can suck the fuel stored in the fuel tank 20 and distribute it to the low pressure fuel pipe 22 and supply the pressurized fuel to the port injection valve 16.

  On the other hand, the low pressure fuel pipe 22 is provided with a high pressure fuel pipe 26 branched from the pipe 22 on the downstream side of the low pressure pump 24. The high-pressure fuel pipe 26 is connected to each in-cylinder injection valve 18 via a high-pressure pump 28 and another fuel pipe 30. As a result, the high pressure pump 28 can pressurize the fuel in two stages together with the low pressure pump 24 and distribute it to the high pressure fuel pipe 26 to supply high pressure fuel to the in-cylinder injection valve 18. The operating states of these pumps 24 and 28 are controlled by an ECU 40 described later.

  Next, a control system of the internal combustion engine 10 will be described. First, the internal combustion engine 10 includes various sensors including a rotation sensor 32, an air flow meter 34, a temperature sensor 36, and an alcohol concentration sensor 38. In this case, the rotation sensor 32 outputs a detection signal corresponding to the rotation speed of the output shaft of the internal combustion engine 10 (engine rotation speed Ne). The air flow meter 34 detects the flow rate of air flowing through the intake passage 14 as the intake air amount Ga. Further, the temperature sensor 36 constitutes the temperature detection means of the present embodiment, and detects the temperature Tw of the cooling water of the internal combustion engine 10. Further, the alcohol concentration sensor 38 constitutes the alcohol concentration detection means of the present embodiment, and detects the alcohol concentration Ma in the fuel stored in the fuel tank 20.

  In addition, the system configuration of the present embodiment includes an ECU (Electronic Control Unit) 40 that controls the operating state of the internal combustion engine 10. The ECU 40 is constituted by a microcomputer or the like, and has a storage circuit 40a composed of ROM, RAM, and the like. In the storage circuit 40a, map data shown in FIGS. 2 to 5 described later and a program shown in FIG. 6 are stored in advance.

  Various sensors including a rotation sensor 32, an air flow meter 34, and a temperature sensor 36 are connected to the input side of the ECU 40. Various actuators including the port injection valve 16 and the pumps 24, 28 are connected to the output side of the ECU 40, and a drive circuit 42 that drives the in-cylinder injection valve 18 is connected.

  The ECU 40 detects the operation state of the internal combustion engine 10 and the operation operation of the operator by the sensors, and performs various controls including fuel injection control and ignition timing control according to the detection result. In this case, in the fuel injection control, the fuel injection amount is calculated according to the operating state of the internal combustion engine 10 and the injection region variable control, port injection region variable control, etc. described later are executed.

[Characteristics of Embodiment 1]
2 to 5 show map data for fuel injection control stored in advance in the storage circuit 40a of the ECU 40. FIG. The map data of FIG. 2 shows the division of the region set in the operation region of the internal combustion engine 10. In other words, the entire operation region of the internal combustion engine 10 is divided into three types of regions according to, for example, the engine speed Ne and the load factor KL, as indicated by a solid line in FIG. In this case, the load factor KL is a numerical value corresponding to the load state (intake air charging efficiency) of the internal combustion engine 10, and is calculated using the engine speed Ne, the intake air amount Ga, the cylinder volume, and the like. is there.

  These three types of regions are a port injection region P where only the port injection valve 16 performs fuel injection (port injection), and a cylinder injection region D where only the cylinder injection valve 18 performs fuel injection (in-cylinder injection). And both the injection valves 16 and 18 are comprised by the injection division area | region PD which performs fuel injection.

  Here, the port injection region P is set mainly in a low rotation / low load operation region in the entire operation region of the internal combustion engine 10. In this operating region, the amount of intake air is relatively small and its fluidity is low, so that it is difficult to form a homogeneous air-fuel mixture with in-cylinder injection. On the other hand, the fuel injected into the intake passage 14 by the port injection valve 16 is mixed with the intake air before reaching the combustion chamber, so that a relatively homogeneous mixture can be formed. For this reason, in the port injection region P, a stable combustion state can be realized by the port injection valve 16, and torque fluctuations and the like of the internal combustion engine 10 operated at a low speed can be suppressed.

  Further, the spray dividing area PD is set mainly in an operation area where the rotation is low and the load is high. In this operating region, if only port injection is performed, the tip of the in-cylinder injection valve 18 that does not inject fuel becomes hot, and deposits and the like are likely to accumulate in this region. Moreover, the output of the internal combustion engine 10 may be insufficient only by port injection. On the other hand, if only in-cylinder injection is performed, a heterogeneous mixture is likely to be formed for the reasons described above. For this reason, in the injection division area PD, fuel is injected from the injection valves 16 and 18 at an appropriate ratio.

  Further, the in-cylinder injection region D is mainly set to an operation region with high rotation and high load. In this operating region, it is required to operate the internal combustion engine 10 with a relatively large output. For this reason, in the intake stroke, it is preferable to increase the charging efficiency as much as possible without causing knocking or the like. In this case, the fuel directly injected from the in-cylinder injection valve 18 into the cylinder 12 takes the heat of vaporization from the surroundings when vaporized, so that the substantial intake air temperature can be lowered and high charging efficiency can be realized. Can do. Therefore, in the in-cylinder injection region D, a sufficient output can be obtained by the in-cylinder injection valve 18.

(Variation control of spray area)
In the present embodiment, it is configured to perform variable spray area control on the above-described spray area PD. As shown by a dotted line in FIG. 2, the variable injection region control is performed such that the higher the alcohol concentration Ma in the fuel, the higher the rotation region (in-cylinder injection region D side) of the injection region PD. It will be expanded gradually.

  Here, when the alcohol concentration Ma is high, deposit-causing components (olefin, sulfur, etc.) contained in the gasoline are diluted, and the concentration of these components in the fuel becomes low. For this reason, even if the tip temperature of the in-cylinder injection valve 18 rises to some extent, deposits are difficult to accumulate. Also, when fuel with a high alcohol concentration is burned, the amount of heat generated by the fuel is reduced as compared with the case of gasoline alone, so that the total fuel injection amount increases to compensate for this.

  As a result, for example, the port injection valve 16 can be operated together even in a region where only the in-cylinder injection valve 18 is operated conventionally. That is, in the conventional in-cylinder injection region, the fuel injection amount of the in-cylinder injection valve 18 is reduced by an amount that makes deposits difficult to accumulate, and the port injection valve 16 can be operated together by this reduced amount. Further, depending on the operation region, the port injection valve 16 can be operated together with the increase in the total fuel injection amount without reducing the fuel injection amount of the in-cylinder injection valve 18.

  Thus, according to the present embodiment, it is possible to appropriately set the range of the spraying region PD according to the alcohol concentration Ma. That is, the operating area of the port injection valve 16 can be expanded as necessary while protecting the in-cylinder injection valve 18 from deposits. As a result, a homogeneous air-fuel mixture can be formed by the port injection valve 16 while satisfying the demand for the output of the internal combustion engine 10 by the in-cylinder injection valve 18 in a wide range of the operation region. Therefore, driving performance such as fuel consumption and torque fluctuation can be improved.

  Next, FIG. 3 illustrates one-dimensional spray area map data used in the above-described spray area variable control. This map data sets the correspondence between the alcohol concentration Ma and the spray separation area PD. In FIG. 3, the specific concentration values Ma0 to Ma4 of the alcohol concentration Ma have a magnitude relationship of Ma0 <Ma1 <Ma2 <Ma3 <Ma4.

  Regions PD0 to PD4 are specific examples of the spray dividing region PD shown in FIG. 2, and the size thereof is set as PD0 <PD1 <PD2 <PD3 <PD4. In the present embodiment, in order to simplify the description, the map data in which the density values Ma0 to Ma4 and the regions PD0 to PD4 are each composed of five elements is illustrated. However, the present invention is not limited to this, and the number of elements of the map data may be set to an arbitrary number.

  Further, the data of the individual regions PD0 to PD4 are set by, for example, the engine speed Ne and the load factor KL, respectively. For example, the region PD0 is a region where the engine speed Ne is the boundary value Ne0 or less and the load factor KL is the boundary value KL0 or more. Therefore, for example, when determining whether or not the operating state of the internal combustion engine 10 belongs to the region PD0, the engine speed Ne and the load factor KL in this operating state may be compared with the boundary values Ne0 and KL0. In addition, discrimination processing for other regions can also be performed by the same comparison operation.

  For example, when the alcohol concentration Ma is the concentration value Ma1, the ECU 40 refers to the spray area map data and sets the spray area PD as the area PD1. Similarly, when the alcohol concentration Ma becomes the concentration value Ma2, the spray dividing region PD is set in the region PD2. In this way, as the alcohol concentration Ma becomes higher, the spray area PD can be sequentially expanded. On the other hand, when a fuel with a low alcohol concentration Ma is used, the spray area PD can be reduced to an appropriate range.

(Port injection range variable control)
In the present embodiment, the port injection region variable control is performed in addition to the above-described spray division region variable control. FIG. 4 is map data showing the operation of the port injection region variable control. In the port injection region variable control, as indicated by a dotted line in FIG. 4, as the temperature Tw of the cooling water of the internal combustion engine 10 becomes lower, the port injection region P is changed to the in-cylinder injection region D side (the higher rotation side of the engine speed Ne). And gradually increase toward the high load side of the load factor KL).

  Further, the port injection region variable control is configured to expand the port injection region P toward the in-cylinder injection region D even when the alcohol concentration Ma is high, as shown in FIG. 5 described later. In these processes, for example, the port injection region P is expanded from a low rotation / low load operation region to a middle rotation / middle load operation region.

  Here, when the internal combustion engine 10 is in a low temperature state (the state before warming up), the injected fuel is difficult to vaporize, and therefore the air-fuel mixture becomes inhomogeneous and burns particularly in the operation region other than the high rotation and high load. The state is likely to fluctuate. Therefore, in this case, for example, by expanding the port injection region P to a mid-range rotation / mid-range load operation region, it is possible to improve driving performance such as fuel consumption and torque fluctuation over a wide range of the driving region. Further, if the port injection region P is enlarged, the frequency of opening and closing the in-cylinder injection valve 18 that performs fuel injection at a high pressure can be reduced. As a result, it is possible to reduce a relatively large operating noise (noise) when the in-cylinder injection valve 18 operates.

  On the other hand, when the alcohol concentration Ma is high, as described above, the causative component of the deposit contained in the gasoline is diluted, so that it is difficult for the deposit to accumulate on the tip side of the in-cylinder injection valve 18. For this reason, in the comparatively wide driving | running area | region, it becomes possible to make the in-cylinder injection valve 18 stop and to operate only the port injection valve 16. FIG. Thereby, fuel consumption and torque fluctuation can be improved while protecting the in-cylinder injection valve 18 from deposits.

FIG. 5 exemplifies two-dimensional map data used for the port injection region variable control described above. This map data includes a plurality of types of region setting data En (n = 0 to 100) set in advance corresponding to different alcohol concentrations Ma. In this case, the subscript n attached to En is the alcohol concentration (%). Accordingly, FIG. 5 shows the region setting data E ₀ , E ₂₅ , E ₅₀ , E ₇₅ , E used respectively when the alcohol concentration in the fuel is 0%, 25%, 50%, 75%, 100%. ₁₀₀ is illustrated.

  Each region setting data En is configured as one-dimensional map data for setting an optimum port injection region P according to the temperature Tw. Further, specific temperature values Tw0 to Tw8 of the temperature Tw are determination temperatures for determining whether or not to expand the port injection region P, and Tw0 <Tw1 <... <Tw8 as illustrated. Has a large and small relationship. Further, regions P0 to P4 are specific examples of the port injection region P shown in FIG. 4, and the size thereof is set as P0 <P1 <P2 <P3 <P4.

Therefore, the ECU 40 selects the region setting data E ₂₅ in this map data when the alcohol concentration Ma in the fuel is 25%, for example. Then, for example, when the temperature Tw is lower than temperature value Tw3, from referring to the region setting data E _25, the port injection region P can be expanded from a region P1 to the region P2.

In the case for example an alcohol concentration Ma 50%, also when the temperature Tw is lower than temperature value Tw3, by the area setting data E ₅₀ in FIG. 5 is selected, to be referenced, the port injection region P is The area P2 is enlarged to the area P3. That is, when the temperature condition is considered to be constant, the port injection region P is expanded as the alcohol concentration Ma increases. In other words, the temperature at which the constant region expansion operation is performed on the port injection region P is shifted to a higher temperature side as the alcohol concentration Ma is higher. On the other hand, when the alcohol concentration Ma and the temperature Tw are low, the port injection region P can be reduced to an appropriate range.

[Specific Processing for Realizing Embodiment 1]
FIG. 6 is a flowchart of a routine executed by the ECU 40 during fuel injection control in order to realize the system operation of the present embodiment. The routine shown in FIG. 6 is started when the internal combustion engine 10 is started, and is repeatedly executed at regular intervals.

  In this fuel injection control, first, in step 100, the engine speed Ne, the intake air amount Ga, the temperature Tw, and the alcohol concentration Ma are detected by reading detection signals from the sensors 32, 36, and 38 and the air flow meter 34. . In step 102, the load factor KL is calculated using the engine speed Ne, the intake air amount Ga, the cylinder volume, and the like.

  Next, in step 104, a specific range of the spraying region PD is set by referring to the spraying region map data of FIG. 3 using the alcohol concentration Ma. In step 106, the specific range of the port injection region P is set by referring to the port injection region map data in FIG. 5 using the alcohol concentration Ma and the temperature Tw. In step 108, the map data of the final region classification is created by synthesizing the setting contents of steps 104 and 106.

  Next, in step 110, by referring to the final map data using the engine speed Ne and the load factor KL, the current operation state is the port injection region P, the in-cylinder injection region D, the injection division region. It is determined to which area of the PD it belongs. In step 112, fuel is injected from one or both of the injection valves 16, 18 according to the determination result.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. Here, the system of the present embodiment adopts the system configuration shown in FIG. 1 as in the first embodiment. Moreover, in this Embodiment, the same code | symbol shall be attached | subjected to the component same as Embodiment 1, and the description shall be abbreviate | omitted.

[Characteristics of Embodiment 2]
7 to 9 show map data for fuel injection control stored in advance in the storage circuit 40a of the ECU 40 in the present embodiment. In this case, FIG. 7 is low-concentration map data used when the alcohol concentration Ma is equal to or lower than the predetermined determination concentration Mx. In this map data, a case where the operation region of the internal combustion engine 10 is configured by the port injection region P and the in-cylinder injection region D is illustrated.

  FIG. 8 shows map data for high concentration used when the alcohol concentration Ma is higher than the determination concentration Mx. As can be seen from these drawings, in the present embodiment, when the alcohol concentration Ma is higher than the determination concentration Mx, the spraying region PD is provided along the fully open region F in the operation region. In this case, the fully open region F is an operating region along a characteristic line showing the relationship between the engine speed Ne and the load factor KL when the throttle valve of the internal combustion engine 10 is fully opened.

  When the alcohol concentration Ma in the fuel is high, the calorific value of the fuel is lower than that in the case of gasoline alone, so that the fuel injection amount increases to compensate for this. For this reason, even when the maximum amount of fuel that can be injected by the in-cylinder injection valve 18 is injected in the fully open region F that requires a large amount of fuel injection and in the vicinity thereof, the fuel injection may be insufficient.

  In such a case, in the present embodiment, the spray-dividing region PD can be arranged along the fully open region F. As a result, in the vicinity of the fully open region F, the fuel injection amount that is insufficient with the in-cylinder injection valve 18 alone can be compensated by the port injection valve 16, and a sufficient amount of fuel is injected by the two injection valves 16 and 18. Can do. The determination concentration Mx for determining the magnitude of the alcohol concentration Ma is set in advance as an alcohol concentration value such that the fuel injection amount in the fully open region F is equal to or less than the maximum injection amount of the in-cylinder injection valve 18, for example.

  On the other hand, in the present embodiment, as shown in FIG. 9, the port injection region variable control that is substantially the same as that in the first embodiment is performed. Therefore, the map data shown in FIG. 5 is stored in advance in the storage circuit 40a of the ECU 40. Therefore, also in the present embodiment, it is possible to obtain substantially the same operational effects as in the first embodiment by the port injection region variable control.

[Specific Processing for Realizing Embodiment 2]
FIG. 10 is a flowchart of a routine executed by the ECU 40 during the fuel injection control in order to realize the system operation of the present embodiment. Note that the routine shown in FIG. 10 is started when the internal combustion engine 10 is started, and is repeatedly executed at regular intervals.

  In this fuel injection control, first, at step 120, the engine speed Ne, the intake air amount Ga, the temperature Tw, and the alcohol concentration Ma are detected. In step 122, the load factor KL is calculated by the same method as in the first embodiment.

  Next, at step 124, the port injection region variable control similar to that of the first embodiment is performed using the map data shown in FIG. And the execution result of this control is reflected in the map data of FIG.7 and FIG.8.

  Next, in step 126, it is determined whether or not the alcohol concentration Ma is higher than the determination concentration Mx. If it is determined “YES”, the process proceeds to step 128. If “NO” is determined in the step 126, the process proceeds to a step 130.

  In step 128, the current operating state is determined to be the port injection region P, the in-cylinder injection region D, the injection by referring to the map data for high concentration shown in FIG. 8 using the engine speed Ne and the load factor KL. It is determined which of the divided areas PD belongs to. On the other hand, in step 130, it is determined whether the current operating state belongs to the port injection region P or the in-cylinder injection region D by referring to the map data for low concentration shown in FIG. In step 132, fuel injection is executed according to the determination result of either step 128 or 130.

  Thus, according to the present embodiment, a sufficient amount of fuel can be injected by the two injection valves 16 and 18 even in the fully open region F of the internal combustion engine 10 that requires a large amount of fuel injection. The operation in the region F can be performed stably. Further, when designing the internal combustion engine 10, it is necessary to set the maximum injection amount of the individual injection valves 16 and 18 forcibly large with reference to the amount of fuel required in the fully open region F when the alcohol concentration Ma is high. Absent. For this reason, it is possible to appropriately design the port injection valve 16 and the in-cylinder injection valve 18, respectively, and it is possible to suppress an increase in cost.

  In the first embodiment, the map data shown in FIGS. 2 and 3 and step 104 shown in FIG. 6 show a specific example of the spray dividing area varying means. Further, the map data shown in FIGS. 4 and 5 and step 106 shown in FIG. 6 show a specific example of the port injection region varying means. Further, in the second embodiment, the map data shown in FIGS. 7 and 8 and step 126 shown in FIG. 10 show a specific example of the spray dividing region varying means, and the map data shown in FIG. Step 124 shown in the figure shows a specific example of the port injection region varying means.

  Moreover, in Embodiment 1, it was set as the structure which expands the spraying area | region PD according to alcohol concentration Ma. On the other hand, in the second embodiment, when the alcohol concentration Ma is high, the spray area PD is provided along the fully open area F. However, the present invention is not limited to performing these configurations individually. That is, in the present invention, by combining the first and second embodiments, when the alcohol concentration Ma is high, the spray-split area PD is enlarged and another spray-split area PD is provided along the fully open area F. Also good.

  Moreover, in Embodiment 1, 2, it was set as the structure which performs injection division area | region variable control and port injection area | region variable control. However, the present invention is not limited to this, and for example, only the spray area variable control may be executed alone. Moreover, it is good also as a structure which performs only a port injection area | region variable control independently, without performing an injection division area | region variable control.

  In each of the above embodiments, the temperature Tw of the cooling water is detected as the substantial temperature of the internal combustion engine 10. However, the present invention is not limited to this, and for example, the temperature of the cylinder block, cylinder head, exhaust gas, etc. of the internal combustion engine 10 is detected, and the injection region variable control and the port injection region variable control are performed according to the detection result. It is good also as a structure.

  Further, in each of the above embodiments, the load factor KL is used as a parameter representing the load state of the internal combustion engine 10. However, the present invention is not limited to this, and as a parameter representing the load state, for example, a parameter such as a throttle opening of the internal combustion engine 10 or an intake air amount, or a parameter such as torque calculated by these parameters is used. Also good.

It is a whole block diagram which shows the control apparatus of the internal combustion engine by Embodiment 1 and Embodiment 2 of this invention. It is explanatory drawing which shows the map data for expanding the injection division area | region in the driving | operation area | region of an internal combustion engine. It is explanatory drawing which shows the map data for setting a spray division area | region according to the alcohol concentration in a fuel. It is explanatory drawing which shows the map data for expanding a port injection area | region in the driving | operation area | region of an internal combustion engine. It is explanatory drawing which shows the map data for setting a port injection area | region according to the alcohol concentration in a fuel, and the cooling water temperature of an internal combustion engine. It is a flowchart of the routine performed in Embodiment 1 of the present invention. In Embodiment 2 of this invention, it is explanatory drawing which shows the map data of the driving | operation area | region at the time of using the fuel with low alcohol concentration. FIG. 8 is an explanatory diagram showing map data of an operation region when a fuel having a high alcohol concentration is used with respect to FIG. 7. It is explanatory drawing which shows the map data for expanding a port injection area | region in the driving | operation area | region of an internal combustion engine. It is a flowchart of the routine performed in Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 12 Cylinder 12a Intake port 14 Intake passage 16 Port injection valve 18 In-cylinder injection valve 20 Fuel tank 22 Low pressure fuel piping 24 Low pressure pump 26 High pressure fuel piping 28 High pressure pump 30 Fuel piping 32 Rotation sensor 34 Air flow meter 36 Temperature sensor ( Temperature detection means)
38 Alcohol concentration sensor (alcohol concentration detection means)
40 ECU
P Port injection region D In-cylinder injection region PD Injection region Ne Engine speed Ga Intake air amount Tw Temperature Ma Alcohol concentration
KL load factor Mx judgment concentration

Claims (5)

A port injection valve for injecting fuel toward the intake port of the internal combustion engine;
An in-cylinder injection valve for injecting fuel into the cylinder of the internal combustion engine;
Alcohol concentration detection means for detecting the alcohol concentration in the fuel;
Of the operating range determined according to the engine speed and the load state of the internal combustion engine, the range of the injection divided region where both the port injection valve and the in-cylinder injection valve inject fuel is determined according to the alcohol concentration. A spray dividing region variable means for setting the variable;
A control device for an internal combustion engine, comprising:   2. The control device for an internal combustion engine according to claim 1, wherein the spray distribution region varying means is configured to expand the spray distribution region as the alcohol concentration increases.   3. The internal combustion engine according to claim 1, wherein the spray region changing unit is configured to provide the spray region along a fully open region of the operation region when the alcohol concentration is higher than a determination concentration. Control device.   Temperature detection means for detecting the temperature of the internal combustion engine, and port injection area variable means for expanding a port injection area in which only the port injection valve injects fuel in the operating area as the temperature detected by the temperature detection means becomes lower The control apparatus for an internal combustion engine according to claim 1, 2 or 3. The control apparatus for an internal combustion engine according to claim 4 , wherein the port injection region variable means is configured to expand the port injection region as the concentration of alcohol contained in the fuel increases.

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