JP5672930B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that includes a dual injection system that performs in-passage injection (also referred to as port injection) and in-cylinder injection (also referred to as direct injection) and a water pump.

  In general, during the cold operation of the engine, that is, during the warm-up operation, the temperature of the inner wall surface of the cylinder is low, so that if the fuel supplied into the combustion chamber adheres to the inner wall surface of the cylinder, the fuel is less likely to volatilize. Therefore, this “fuel dilution” is likely to occur, in which the fuel that has not volatilized leaks into the crank chamber from the gap between the piston and the inner wall surface of the cylinder and mixes with the oil in the crank chamber.

  Incidentally, in recent years, it is known that an internal combustion engine is provided with a dual injection system in order to improve combustion efficiency and reduce fuel consumption (see, for example, Patent Document 1).

  An internal combustion engine including such a dual injection system includes a port injector for injecting fuel into an intake port of a cylinder head and an in-cylinder injector for injecting fuel into a combustion chamber.

  In this patent document 1, considering that the amount of particulate matter (PM) generated in the exhaust gas increases when the fuel injected into the combustion chamber does not burn completely while adhering to the piston or intake valve, When the temperature is lower than the reference value and the intake valve temperature is lower than the reference value, the injection ratio in the passage is made higher than when the piston temperature is higher than the reference value and the intake valve temperature is higher than the reference value. I have to.

  In addition, for example, in Patent Document 2, in an internal combustion engine including a mechanical water pump and an electric water pump, cooling water having a flow rate corresponding to the thermal load of the cylinder head is caused by the electric water pump in the vicinity of the exhaust port of the cylinder head. It is described that the operation of the electric water pump is controlled to flow. In addition, in this patent document 2, there is no description that the fuel injection type is in-passage injection (also referred to as port injection) or in-cylinder injection (also referred to as direct injection), but see the description of FIG. 2 of this patent document 2. Since there is no injector for in-cylinder injection, it is expected that the injection is in general passage. That is, it can be said that the conventional example shown in Patent Document 2 presents an internal combustion engine that does not include a dual injection system.

JP 2009-197705 A JP 2005-36729 A

  Although the above-mentioned patent document 1 shows an internal combustion engine having a dual injection system, there is no description regarding fuel dilution accompanying an increase in the ratio of in-cylinder injection, and there is no description regarding control of the water pump.

  Moreover, although the said patent document 2 has description of controlling operation | movement of an electric water pump in an internal combustion engine provided with a mechanical water pump and an electric water pump, the internal combustion engine of this patent document 2 is a dual injection system. When the ratio of in-cylinder injection to in-cylinder injection and in-cylinder injection increases when the coolant temperature is low, such as during cold operation, the fuel is We have not found a problem that dilution is likely to occur.

  In view of such circumstances, the present invention relates to a control device for an internal combustion engine that includes a dual injection system that performs in-passage injection and in-cylinder injection, and that includes a water pump. The purpose of this is to make it possible to suppress the occurrence of fuel dilution when the ratio of in-cylinder injection increases.

The present invention relates to a fuel injection valve for in-cylinder injection that injects fuel into a combustion chamber of an internal combustion engine, a fuel injection valve for injection into a passage that injects fuel into an intake passage connected to the combustion chamber, and an internal combustion engine An internal combustion engine control device comprising an electric water pump that circulates cooling water of the engine, and when it is determined that the internal combustion engine is in cold operation, as the ratio of in-cylinder injection increases, When it is determined that the internal combustion engine is in warm operation while reducing the cooling water discharge flow rate of the water pump, the cooling water discharge flow rate of the water pump is set to the injection ratio between the in-passage injection and the in-cylinder injection. Regardless of whether the internal combustion engine load and the engine speed are parameters, the cooling water discharge flow rate of the water pump is determined according to a flow rate control map .

  In the first place, fuel dilution is relatively easy to occur when the cooling water temperature is low, such as during cold operation or warm-up operation of the internal combustion engine, and after the warm-up operation of the internal combustion engine, that is, after the warm-up operation ends. In such a situation where the coolant temperature is high, fuel dilution is relatively difficult to occur.

  In particular, in an internal combustion engine equipped with a dual injection system that performs in-passage injection and in-cylinder injection, the ratio of in-cylinder injection increases when the temperature of the inner wall surface of the cylinder is relatively low, such as during cold operation of the internal combustion engine. As a result, fuel dilution is likely to occur.

  Therefore, in the present invention, the cooling water discharge flow rate by the water pump is decreased as the ratio of in-cylinder injection increases in a situation where the cooling water temperature is in a low temperature range where fuel dilution is likely to occur, such as during cold operation of the internal combustion engine. I am doing so.

  As a result, even if the ratio of in-cylinder injection increases in the above situation, the cylinder inner wall surface is not supercooled and the temperature rise is promoted. Therefore, even if fuel adheres to the inner wall surface of the cylinder due to the in-cylinder injection, the volatilization of the fuel is promoted, and the fuel can be prevented from being mixed into the oil in the crank chamber. Can be suppressed. Therefore, it becomes possible to contribute to improvement of fuel consumption and to avoid deterioration of oil.

  In addition, if the cooling water discharge flow rate by the water pump is reduced in a situation where the cooling water temperature is in a low temperature range where the fuel dilution is likely to occur as in the cold operation, the internal combustion engine can be Although there is a high possibility of knocking, if the ratio of in-cylinder injection increases as described above, the intake air cooling effect associated with increasing the ratio of in-cylinder injection increases, so knocking may occur. It becomes possible to lower the sex. That is, the adverse effect of reducing the cooling water discharge flow rate does not occur as described above. Note that the temperature range in which knocking is likely to occur varies depending on the compression ratio of the internal combustion engine. For example, as the compression ratio increases, the temperature range where knocking is likely to occur decreases.

Further, in the control device, to identify the control mode of the water pump in the fuel is evaporated situation susceptible to coolant temperature is attached to the cylinder inner wall surface is hot zone as warm during the operation of the internal combustion engine Yes.

  Preferably, the control device determines whether or not the cooling water temperature of the internal combustion engine is in a temperature range during cold operation, and determines an injection ratio between the in-passage injection and the in-cylinder injection. A ratio determining means and a discharge flow rate determination for determining the cooling water discharge flow rate of the water pump based on a flow rate control map in which the cooling water discharge flow rate of the electric water pump is set using the load of the internal combustion engine and the engine speed as parameters. The cooling water discharge flow rate determined by the discharge flow rate determination unit is determined by the ratio determination unit when the cooling water temperature of the internal combustion engine is determined to be in a temperature range during cold operation by the determination unit. First coping means for correcting to reduce as the ratio of in-cylinder injection increases, and the discharge flow rate determining means when it is determined that the cooling water temperature of the internal combustion engine is in a temperature range during warm operation The determined cooling water discharge flow rate was, and a second addressing means is not corrected regardless injection distribution ratio is determined by the ratio determining means can be configured.

  In this configuration, the function realizing means of the control device is specified. Thereby, it becomes easy to embody the control form of the control device.

  The present invention includes a dual injection system that performs in-passage injection and in-cylinder injection, and in a control device for an internal combustion engine that includes a water pump, when the internal combustion engine is in cold operation and the ratio of in-cylinder injection increases. It becomes possible to suppress the occurrence of fuel dilution.

It is a figure showing a schematic structure of one embodiment of an internal-combustion engine to which the present invention is applied. It is a figure which shows schematic structure of the cooling system of the internal combustion engine shown in FIG. 2 is a flow rate control map in which the cooling water discharge flow rate of the electric water pump is set with the load and the rotation speed of the internal combustion engine shown in FIG. 1 as parameters. It is a flowchart regarding operation | movement control of the electric water pump by the control apparatus shown in FIG. FIG. 3 is a correction map in which a correction ratio of the cooling water discharge flow rate of the electric water pump is set with the injection ratio between in-passage injection and in-cylinder injection shown in FIG. 1 as a parameter.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  1 to 5 show an embodiment of the present invention. First, a schematic configuration of the internal combustion engine 1 will be described with reference to FIG.

  A piston 5 is disposed in the cylinder 4 of the cylinder block 2 of the internal combustion engine 1 so as to be reciprocally movable. The piston 5 is connected to a crankshaft 7 via a connecting rod 6.

  A signal rotor 201 is attached to the crankshaft 7. A plurality of teeth (protrusions) are provided on the outer peripheral surface of the signal rotor 201 at equal angles (for example, 10 ° CA (crank angle)), but a predetermined number of teeth at a predetermined position on the circumference thereof are missing. A missing tooth portion is provided. A crank position sensor 202 is disposed near the side of the signal rotor 201. The crank position sensor 202 is, for example, an electromagnetic pickup, and generates a pulsed signal (voltage pulse) corresponding to the teeth of the signal rotor 201 when the crankshaft 7 rotates. Then, the control device 100 calculates the rotation angle, rotation speed, rotation speed Ne, and the like of the crankshaft 7 based on the output signal of the crank position sensor 202.

  An intake valve 8 and an exhaust valve 9 are assembled to the cylinder head 3 of the internal combustion engine 1. The intake valve 8 and the exhaust valve 9 are individually opened and closed by camshafts (not shown).

  The intake passage 11 of the internal combustion engine 1 includes an intake port 3a provided in the cylinder head 3 and an intake pipe 12 connected to the intake port 3a. An air flow meter 203 is provided in the intake passage 11. The air flow meter 203 outputs a signal corresponding to an intake air flow rate Ga which is a mass flow rate per unit time of intake air flowing through the intake pipe 12.

  An electronically controlled throttle valve 13 for adjusting the intake air flow rate Ga is provided in the intake passage 11. The throttle valve 13 is driven by a throttle motor 14. Further, the opening degree of the throttle valve 13 is detected by the throttle position sensor 204 and controlled by the control device 100. The throttle position sensor 204 inputs a signal corresponding to the rotational phase (throttle valve opening) of the throttle valve 13 to the control device 100. Normally, when the amount of depression of an accelerator pedal (not shown) becomes zero, that is, when the accelerator is off, the control device 100 sets the opening of the throttle valve 13 as the idling opening. The idling opening is an opening necessary for the internal combustion engine 1 to maintain the idling speed.

  Further, the exhaust passage 15 of the internal combustion engine 1 includes an exhaust port 3 b provided in the cylinder head 3 and an exhaust pipe 16. A catalytic converter 17 is installed in the exhaust pipe 16.

  The internal combustion engine 1 includes an in-passage fuel injection valve 18 for injecting fuel into the intake passage 11, and an in-cylinder injection fuel injection valve 19 for injecting fuel directly into the combustion chamber 1a. Is provided. In this embodiment, the fuel injection valve 18 for in-passage injection is installed so as to inject fuel into the intake port 3 a of the intake passage 11. The fuel injection operations of these fuel injection valves 18 and 19 are controlled by the control device 100.

  Since the internal combustion engine 1 is a gasoline engine in this embodiment, the control device 100 determines the ignition timing of an ignition plug (not shown) installed in the cylinder head 3 and the fuel injection timing of the fuel injection valves 18 and 19. The operation of the internal combustion engine 1 is controlled by controlling at.

  Next, a cooling system for the internal combustion engine 1 will be described with reference to FIG. Since the cooling system shown in this embodiment has a known configuration, it will be briefly described.

  The internal combustion engine 1 is equipped with an electric water pump 21. When the electric water pump 21 is operated, cooling water is circulated between the internal passage and the external passage of the internal combustion engine 1. The electric water pump 21 is controlled by the control device 100.

  Examples of the internal passage include a water jacket 2 a provided in the cylinder block 2 and a water jacket 3 c provided in the cylinder head 3. Examples of the external passage include a radiator passage 23 for sending cooling water to the radiator 22, a bypass passage 24 for bypassing the radiator 22, and a heater passage 26 for sending cooling water to the heater core 25.

  In this embodiment, a cooling water temperature sensor 205 is installed in the water jacket 2a of the cylinder block 2 (see FIG. 1). The cooling water temperature sensor 205 outputs a signal corresponding to the temperature of the cooling water in the water jacket 2a.

  For example, during the cold operation of the internal combustion engine 1, that is, when the cooling water temperature is lower than an appropriate reference value, the thermostat 27 causes the cooling water to flow through the bypass passage 24 so as not to pass through the radiator 22 and then returns to the internal combustion engine 1. Put it in a state. On the other hand, during the warm operation of the internal combustion engine 1, that is, when the cooling water temperature is equal to or higher than the reference value, the thermostat 27 flows the cooling water through the radiator passage 23 so as to pass through the radiator 22 and then returns to the internal combustion engine 1. To do.

  The control device 100 is an electronic control unit (ECU), not shown in detail, but a CPU (central processing unit), ROM (program memory), RAM (data memory), backup RAM (nonvolatile memory), and the like. It is set as the well-known structure provided with.

  The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU executes arithmetic processing based on various control programs and maps stored in the ROM. The RAM is a memory that temporarily stores the calculation results of the CPU, data input from each sensor, and the like. The backup RAM is a nonvolatile memory that stores data to be saved when the internal combustion engine 1 is stopped. Memory. Examples of sensors connected to the control device 100 in this embodiment include a crank position sensor 202, an air flow meter 203, a throttle position sensor 204, and a coolant temperature sensor 205. The illustration of other various sensors is omitted.

  For example, the control device 100 performs various controls related to the operation of the internal combustion engine 1 and controls the operation of the electric water pump 21 as described below.

  In order to control the operation state of the internal combustion engine 1 to a target operation state, the control device 100 uses the load of the internal combustion engine 1 and the rotation speed of the internal combustion engine 1 as parameters to perform fuel injection valves for in-passage injection. Control is performed in accordance with a map (not shown) in which the fuel injection ratio is set by the fuel injection valve 18 for in-cylinder injection. The load of the internal combustion engine 1 is an intake air flow rate Ga specified from an output signal of the air flow meter 203 (or an accelerator opening specified from an output signal of an accelerator opening sensor not shown). The rotational speed of the internal combustion engine 1 is obtained from the output signal of the crank position sensor 202.

  Further, the control device 100 controls the operation of the electric water pump 21 based on the flow rate control map shown in FIG. This flow rate control map is a map in which the cooling water discharge flow rate of the electric water pump 21 is set with the load of the internal combustion engine 1 and the rotation speed of the internal combustion engine 1 as parameters.

  Next, operation control of the electric water pump 21 executed by the control device 100 will be described with reference to the flowchart shown in FIG. Note that when the internal combustion engine 1 is started, the control device 100 executes the processing of the flowchart shown in FIG. 4 at regular intervals.

  First, in step S1, it is determined whether or not the coolant temperature of the internal combustion engine 1 is in a temperature range during cold operation, that is, during warm-up operation. Here, the coolant temperature is recognized based on the output signal from the coolant temperature sensor 205, and this recognized coolant temperature is a temperature range during cold operation, preferably a low temperature range where fuel dilution is likely to occur (for example, It is determined whether it is 20 ° C. or less. The low temperature range where the fuel dilution is likely to occur refers to a situation such as during the cold operation of the internal combustion engine 1.

  Here, when the coolant temperature is in a high temperature range where it is difficult for fuel dilution to occur, such as during warm operation, a negative determination is made in step S1, and the process proceeds to step S2. In step S2, the cooling water discharge flow rate by the electric water pump 21 is determined according to the flow rate control map shown in FIG. 3, and the correction result is not corrected. That is, if the determination result is, for example, a value indicated by a line segment bc in FIG. 5, the determination result is set as a final cooling water discharge flow rate without considering the spray distribution ratio. After this step S2, this flowchart is ended.

  On the other hand, when the cooling water temperature is in a low temperature range where fuel dilution is likely to occur, such as during cold operation, an affirmative determination is made in step S1 and the process proceeds to step S3. In step S3, it is determined whether or not the ratio of in-cylinder injection is zero. Here, the control apparatus 100 recognizes the ratio of in-cylinder injection based on the determined value of the injection ratio determined by the separate control using the load and the rotational speed of the internal combustion engine 1 as parameters.

  When the ratio of in-cylinder injection is zero, in other words, when the ratio of in-cylinder injection is 100%, an affirmative determination is made in step S3, and the process proceeds to step S2. In step S2, as described above, the cooling water discharge flow rate by the electric water pump 21 is determined according to the flow rate control map shown in FIG. 3, and the correction result is not corrected. That is, if the determination result is, for example, a value indicated by a point b in FIG. 5, the determination result is set as a final cooling water discharge flow rate without considering the spray distribution ratio.

  On the other hand, when the ratio of in-cylinder injection is not zero, in other words, when performing in-passage injection and in-cylinder injection at an appropriate ratio, a negative determination is made in step S3, and the process proceeds to step S4. In this step S4, the cooling water discharge flow rate by the electric water pump 21 is determined according to the flow rate control map shown in FIG. 3, and the determination result is corrected so as to be reduced according to the spray distribution ratio. This correction is performed, for example, so as to reduce the coolant discharge flow rate by the electric water pump 21 as the ratio of in-cylinder injection increases, as indicated by the line ab in FIG. After this step S4, this flowchart is ended.

  As described above, in the embodiment to which the present invention is applied, the ratio of in-cylinder injection increases in a situation where the cooling water temperature is in a low temperature range where fuel dilution is likely to occur, such as during the cold operation of the internal combustion engine 1. Accordingly, the cooling water discharge flow rate by the electric water pump 21 is reduced.

  As a result, even if the ratio of in-cylinder injection increases in the above situation, the cylinder inner wall surface is not supercooled and the temperature rise is promoted. Therefore, even if fuel adheres to the inner wall surface of the cylinder due to the in-cylinder injection, the volatilization of the fuel is promoted, and the fuel can be prevented from being mixed into the oil in the crank chamber. Can be suppressed. Therefore, it becomes possible to contribute to improvement of fuel consumption and to avoid deterioration of oil.

  In addition, when the cooling water discharge flow rate by the electric water pump 21 is reduced in the situation where the cooling water temperature is in the low temperature range as in the cold operation, the internal combustion engine 1 is knocked in the situation where only the in-passage injection is performed. As described above, if the ratio of in-cylinder injection is large, the intake air cooling effect associated with increasing the ratio of in-cylinder injection is increased. It can be lowered. That is, the adverse effect of reducing the cooling water discharge flow rate does not occur as described above.

  As described above, the present invention is used as a control device for an internal combustion engine having a dual injection system that performs in-passage injection and in-cylinder injection and a water pump.

1 Internal combustion engine
1a Combustion chamber
2 Cylinder block
2a water jacket
3 Cylinder head
3a Intake port
3c water jacket
4 cylinders
7 Crankshaft 11 Intake Passage 18 Fuel Injection Valve for In-Cylinder Injection 19 Fuel Injection Valve for In-Cylinder Injection 21 Electric Water Pump 100 Controller 205 Cooling Water Temperature Sensor

Claims (1)

A fuel injection valve for in-cylinder injection that injects fuel into a combustion chamber of the internal combustion engine, a fuel injection valve for in-passage injection that injects fuel into an intake passage connected to the combustion chamber, and cooling water for the internal combustion engine A control device for an internal combustion engine comprising an electric water pump for circulating
When it is determined that the internal combustion engine is in cold operation, the cooling water discharge flow rate of the water pump is reduced as the ratio of in-cylinder injection increases ,
When it is determined that the internal combustion engine is in warm operation, the cooling water discharge flow rate of the water pump is determined regardless of the injection ratio between the in-passage injection and the in-cylinder injection. A control apparatus for an internal combustion engine, characterized in that it is determined according to a flow rate control map in which the cooling water discharge flow rate of the water pump is set as a parameter .

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