JP4992834B2 - Control device and control method for internal combustion engine - Google Patents

Description

  The present invention relates to control of an internal combustion engine equipped with at least a fuel injection device that injects fuel directly into a cylinder, and more particularly to fuel injection control when the internal combustion engine is cold.

  Conventionally, control for retarding the injection timing when the internal combustion engine is cold is known. For example, Japanese Patent Laying-Open No. 2000-186597 (Patent Document 1) discloses a direct injection internal combustion engine that can suppress the occurrence of a difference between a target air-fuel ratio and an actual air-fuel ratio due to fuel adhering to a cylinder wall surface or the like. This in-cylinder injection type internal combustion engine includes an injection valve that directly injects fuel into a combustion chamber formed by a cylinder head lower surface, a cylinder wall surface, and a piston upper surface that is fitted into the cylinder. Injection timing control means for controlling the injection timing, temperature detection means for detecting the temperature of the internal combustion engine, and injection timing correction means for delaying the injection end timing of the injection valve when the engine temperature detected by the temperature detection means is low And.

According to the in-cylinder injection internal combustion engine disclosed in the above-mentioned publication, when the engine temperature is low, the injection end timing is corrected to an appropriate injection end timing on the retard side so that the piston upper surface or cylinder wall surface is corrected. It is possible to suppress the adhesion of fuel and realize an accurate air-fuel ratio control to prevent deterioration of exhaust gas characteristics at the time of cold start and acceleration failure at start immediately after the start.
JP 2000-186597 A

  However, since there is a limit to the suppression of fuel adhesion due to the retard of the injection timing, there is a case where the torque cannot be generated to the same level as the normal time only by the injection timing. In particular, there is a possibility that atomized fuel that has come into contact with the valve or the like due to the delay of the injection timing adheres to the plug. Therefore, there is a possibility that sufficient torque is not generated.

  In the in-cylinder internal combustion engine disclosed in the above-mentioned publication, such problems are not taken into consideration and cannot be solved.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device and a control method for an internal combustion engine that generates an appropriate torque when the direct injection internal combustion engine is cold. It is to be.

A control device for an internal combustion engine according to a first aspect is a control device for an internal combustion engine mounted on a vehicle. An internal combustion engine includes a fuel injection device that injects fuel directly into at least a cylinder. In this control device, the temperature detection means for detecting the temperature of the internal combustion engine, the intake air amount detection means for detecting the intake air amount of the internal combustion engine, and the temperature of the internal combustion engine are equal to or lower than a predetermined temperature. And an injection control means for controlling the fuel injection device so that the fuel injection timing is delayed when the first condition is satisfied as compared with the case where the first condition is not satisfied. In addition to the first condition, the injection control means, in addition to delaying the fuel injection timing, when the second condition that the state of the internal combustion engine is a return state from the fuel cut control is satisfied, Based on the temperature of the engine and the intake air amount, the fuel injection device is controlled so that the fuel injection amount injected into the cylinder of the internal combustion engine is increased as compared with the case where the second condition is not satisfied , , Further comprising: a rotational speed detection means for detecting the rotational speed of the internal combustion engine; and a means for detecting the throttle opening of the internal combustion engine, wherein the injection control means comprises the first condition and the first In addition to two conditions, a third condition that the detected number of rotations is equal to or less than a predetermined number of rotations, and a fourth condition that the amount of change in the number of rotations is equal to or less than a predetermined amount of change And the second The fifth condition that the elapsed time from the time when the condition is satisfied is within a predetermined time and the sixth condition that the detected throttle opening is equal to or less than the predetermined opening are satisfied. In this case, the fuel injection device is controlled so that the fuel injection amount is increased as compared with the case where any one of the first condition to the sixth condition is not satisfied. An internal combustion engine control method according to an eighth invention has the same configuration as the control device for an internal combustion engine according to the first invention.

According to the first invention, in addition to the first condition, in addition to delaying the fuel injection timing when the state of the internal combustion engine becomes a return state from the fuel cut control, the temperature of the internal combustion engine and the intake air amount Based on the above, the fuel injection device is controlled so that the fuel injection amount is increased as compared with the case where the second condition is not satisfied. Thereby, in addition to suppressing fuel adhesion by delaying the fuel injection timing, the shortage of torque can be compensated by increasing the fuel injection amount. Further, by increasing the fuel injection amount based on the temperature of the internal combustion engine and the intake air amount, it is possible to increase the amount of fuel corresponding to the state of the internal combustion engine. Therefore, it is possible to provide a control device and a control method for an internal combustion engine that expresses an appropriate torque when the direct injection internal combustion engine is cold .
According to the first invention, when the first condition to the sixth condition are satisfied, the fuel injection amount is increased so that the fuel to the wall surface or the piston in the cylinder is cold when the internal combustion engine is cold. In a state where adhesion occurs, it is possible to suppress a shortage of torque generated in the internal combustion engine.

In the control apparatus for an internal combustion engine according to the second invention, in addition to the configuration of the first invention, the temperature detecting means detects the cooling water temperature of the internal combustion engine. The injection control means is a determining means for determining an increase coefficient based on the cooling water temperature of the internal combustion engine and an integrated value of the intake air amount after the internal combustion engine is started, and a fuel injection amount based on the increase coefficient. Means for controlling the fuel injection device. A control method for an internal combustion engine according to a ninth aspect of the present invention has a control device similar to configuration of an internal combustion engine according to the second invention.

  According to the second invention, the increase coefficient is determined based on the cooling water temperature of the internal combustion engine and the integrated value of the intake air amount after the internal combustion engine is started, and the fuel injection amount is based on the increase coefficient. Thus, in addition to suppressing fuel adhesion by delaying the fuel injection timing, the shortage of torque can be compensated by increasing the fuel injection amount. Further, by determining the increase coefficient based on the coolant temperature and the integrated value of the intake air amount, it is possible to increase the fuel injection amount corresponding to the operation history and state of the internal combustion engine.

In the control apparatus for an internal combustion engine according to the third aspect of the invention, in addition to the configuration of the second aspect of the invention, the determining means may increase the coefficient of increase so that the lower the coolant temperature, the greater the degree of increase compared to the higher coolant temperature And means for determining an increase coefficient such that the smaller the integrated value, the greater the degree of increase than when the integrated value is large. An internal combustion engine control method according to a tenth aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the third aspect of the invention.

  According to the third aspect of the invention, the lower the cooling water temperature or the smaller the integrated value, the lower the degree of warm-up, and thus the greater the degree that the injected fuel adheres to the liquid level in the cylinder or the piston. . Therefore, the shortage of torque can be compensated by increasing the fuel injection amount.

In the control apparatus for an internal combustion engine according to the fourth invention, jetting control unit, when either the first condition to the fifth condition is not satisfied, the degree of increase of the fuel injection quantity time The fuel injection device is controlled so as to decrease with the passage of time. An internal combustion engine control method according to an eleventh aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the fourth aspect of the invention.

According to the fourth invention, when any one of the first condition to the fifth condition is not satisfied, the degree of increase in the fuel injection amount is decreased with the passage of time, thereby warming up the internal combustion engine. It is possible to increase the amount of fuel corresponding to the progress. Thereby, an appropriate torque can be generated in the internal combustion engine when it is cold.

In the control apparatus for an internal combustion engine according to the fifth invention, jetting control means, both the first condition to the fifth condition is a case where established, and, if the condition of the sixth is not satisfied In addition, the fuel injection device is controlled so as to stop the fuel increase. An internal combustion engine control method according to a twelfth aspect of the invention has a configuration similar to that of the control device for an internal combustion engine according to the fifth aspect of the invention.

According to the fifth aspect of the present invention, when only the sixth condition for the throttle opening is not satisfied among the first condition to the sixth condition, the increase in the fuel injection amount is stopped, so that an unnecessary fuel increase is achieved. Can be stopped to prevent emissions and fuel consumption from deteriorating.

A control device for an internal combustion engine according to a sixth aspect of the invention includes, in addition to the configuration of any one of the first to fifth aspects, means for detecting a running state of the vehicle that is an execution condition for fuel cut control of the internal combustion engine, And a means for determining that the second condition is satisfied when the execution condition is not satisfied after the execution condition is satisfied based on the detected traveling state. An internal combustion engine control method according to a thirteenth aspect of the present invention has the same configuration as the internal combustion engine control apparatus according to the sixth aspect of the present invention.

According to the sixth invention, after the execution condition of the fuel cut control is satisfied, it is determined that the execution condition is not satisfied, thereby determining that the internal combustion engine is in the return state from the fuel cut control. it can.

In the control device for an internal combustion engine according to the seventh invention, in addition to the configuration of any one of the first to sixth inventions, an automatic transmission connected to the output shaft of the internal combustion engine is mounted on the vehicle. An internal combustion engine control method according to a fourteenth aspect of the invention has a configuration similar to that of the control device for an internal combustion engine according to the seventh aspect of the invention.

According to the seventh invention, for example, when the state of the automatic transmission shifts from the power cut-off state to the traveling state, fuel cut control may be performed to protect the automatic transmission. By applying the present invention to such a case, it is possible to generate an appropriate torque in a state where fuel adhesion occurs.

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

  As shown in FIG. 1, a vehicle equipped with an internal combustion engine control apparatus according to the present embodiment includes an internal combustion engine (hereinafter referred to as an engine) 150, an intake system 152, an exhaust system 154, an ECU ( Electronic Control Unit) 100.

  The engine 150 includes a cylinder block 124, cylinders 162 formed in the cylinder block 124 corresponding to the number of cylinders, a piston 128 slidably provided in the cylinder 162, and one end connected to the piston 128. Piston rod 122, crankshaft 130 connected to the other end of piston rod 122, crankcase 132 that rotatably supports crankshaft 130, crank position sensor 156 that detects the rotational position of crankshaft 130, intake air An intake port 158 for introducing air circulated from the system 152 into the cylinder 162, an intake valve 172 provided at a connection portion between the intake port 158 and the cylinder 162, a fuel injection device 126 for directly injecting fuel into the cylinder 162, , Exhaust gas exhausted from cylinder 162 It includes an exhaust port 160 that circulates in the exhaust system 154, an exhaust valve 174 provided at the connection portion between the exhaust port 160 and the cylinder 162, an ignition plug 176 provided at the top of the cylinder 162.

  The crankshaft 130 is connected to the other end of the piston rod 122 connected to the piston 128 of each cylinder via a crank mechanism. The force to the piston 128 acting by the combustion in each cylinder is converted into the force in the rotation direction of the crankshaft 130 by the crank mechanism.

  The intake valve 172 operates in conjunction with the rotation of the crankshaft 130 to block or communicate the intake port 158 and the cylinder 162. The exhaust valve 174 operates in conjunction with the rotation of the crankshaft 130 to block or communicate the exhaust port 160 and the cylinder 162.

  The crank position sensor 156 transmits a signal indicating the detected rotational speed (hereinafter referred to as engine speed) NE of the crankshaft 130 to the ECU 100.

  The water temperature sensor 106 detects the temperature of cooling water flowing through the engine 150 (hereinafter referred to as cooling water temperature Tw). The water temperature sensor 106 transmits a signal indicating the detected cooling water temperature Tw to the ECU 100.

  The fuel injection device 126 directly injects fuel into the cylinder 162 based on a control signal received from the ECU 100. In the present embodiment, engine 150 may be an engine provided with a fuel injection device that injects at least fuel directly into the cylinder. Engine 150 may be, for example, an engine equipped with a port injector that injects fuel into intake port 158 in addition to fuel injection device 126 that directly injects fuel into cylinder 162. The engine 150 may be an engine that operates with fuel containing at least one of gasoline and alcohol.

  Further, the ECU 100 detects the traveling state of the vehicle that is the execution condition of the fuel cut control, and executes the fuel cut control when the execution condition of the fuel cut control is satisfied. That is, ECU 100 controls fuel injection device 126 to stop fuel injection when a predetermined fuel cut control execution condition is satisfied.

  In the present embodiment, the fuel cut control execution condition is that the vehicle is decelerating (in this embodiment, the opening degree of the throttle valve 112 is equal to or less than a predetermined opening degree). ) And a condition that the rotational speed of the engine 150 is equal to or higher than a predetermined rotational speed. The execution condition of the fuel cut control may further include a condition regarding the speed of the vehicle and a condition regarding the cooling water temperature.

  In the present embodiment, the vehicle is a vehicle equipped with an automatic transmission. Therefore, in the fuel cut control, when the rotational speed of the engine 150 is equal to or higher than a predetermined rotational speed, the shift position changes from the neutral position (hereinafter referred to as N position) to the forward travel position (hereinafter referred to as D position). It is also executed when the condition of changing to (described) is satisfied. In addition, you may make it further include the conditions about cooling water temperature.

  The above-mentioned conditions for the shift position are set for the purpose of protecting the automatic transmission, for example, when the N position erroneously selected by the driver at the start of the vehicle equipped with the automatic transmission is changed to the D position. Is done.

  If the driver depresses the accelerator pedal when the vehicle is erroneously in the N position when the vehicle starts, the engine speed increases. When the driver notices an error in the shift position and changes the shift position from the N position to the D position when the accelerator pedal is depressed or the engine speed is high, an excessive load is applied to the friction engagement element of the automatic transmission. May take. For this reason, the automatic transmission is protected from an excessive load by performing fuel cut control to quickly reduce the engine speed.

  Further, ECU 100 returns from fuel cut control and resumes fuel injection when it is not satisfied after a predetermined execution condition for fuel cut control is satisfied.

  The intake system 152 includes an intake pipe 110 connected to the intake port 158, an air cleaner 118 provided in the middle of the intake pipe 110, and a position in the middle of the intake pipe 110 between the air cleaner 118 and the intake port 158. A throttle valve 112 provided, a throttle motor 114 that operates the throttle valve 112, a throttle position sensor 116 that detects the opening of the throttle valve 112, and the intake pipe 110, between the air cleaner 118 and the throttle valve 112. The intake air temperature sensor 104 provided at the position of FIG. 5, the surge tank 148 provided in the middle of the intake pipe 110 between the throttle valve 112 and the intake port 158, and the air flow meter 190 for detecting the intake air amount are included.

  The throttle position sensor 116 transmits a signal indicating the detected opening of the throttle valve 112 to the ECU 100. The intake air temperature sensor 104 transmits a signal indicating the detected intake air temperature to the ECU 100. The air flow meter 190 transmits a signal indicating the detected intake air amount to the ECU 100. ECU 100 may estimate the intake air amount based on a signal received from a vacuum sensor that detects the degree of negative pressure in intake pipe 110.

  The exhaust system 154 includes an exhaust pipe (1) 108 connected to the exhaust port 160, a three-way catalyst 120 provided in the middle of the exhaust pipe (1) 108, and a middle part of the exhaust pipe (1) 108. In the middle of the air-fuel ratio sensor 200 provided at a position closer to the exhaust port 160 than the original catalyst 120, the exhaust pipe (2) 164 connected to the exhaust pipe (1) 108, and the exhaust pipe (1) 108, It includes an oxygen sensor 102 provided at a position closer to the exhaust pipe (2) 164 than the three-way catalyst 120, and a three-way catalyst 166 provided in the middle of the exhaust pipe (2) 164.

  The air-fuel ratio sensor 200 detects the oxygen concentration in the exhaust gas closer to the exhaust port 160 than the three-way catalyst 120. The air-fuel ratio sensor 200 transmits a signal indicating the detected oxygen concentration in the exhaust gas to the ECU 100. Specifically, the air-fuel ratio sensor 200 outputs an output voltage signal that changes linearly with respect to the oxygen concentration to the ECU 100. ECU 100 calculates the air-fuel ratio based on the output voltage signal received from air-fuel ratio sensor 200.

  The oxygen sensor 102 detects the oxygen concentration in the exhaust gas closer to the exhaust pipe (2) 164 than the three-way catalyst 120. The oxygen sensor 102 transmits a signal indicating the detected oxygen concentration in the exhaust gas to the ECU 100. Specifically, the oxygen sensor 102 outputs to the ECU 100 an output voltage signal that greatly changes the degree of the output voltage before and after the theoretical air-fuel ratio with respect to the oxygen concentration. Based on the output voltage signal received from the oxygen sensor 102, the ECU 100 determines whether the air-fuel ratio is a rich air-fuel ratio or a lean air-fuel ratio with respect to the stoichiometric air-fuel ratio. An air-fuel ratio sensor may be used instead of the oxygen sensor 102.

  When the engine 150 is operated, air is taken into the intake pipe 110. The air drawn into the intake pipe 110 flows toward the intake port 158 via the air cleaner 118. The flow rate of the air flowing through the intake port 158 is limited according to the opening degree of the throttle valve 112.

  The air flowing from the intake port 158 into the cylinder 162 is mixed with the fuel injected from the fuel injection device 126. The air-fuel mixture in which fuel and air are mixed is burned by the ignition plug 176 igniting the air-fuel mixture before and after the piston 128 reaches top dead center after the intake valve 172 and the exhaust valve 174 are closed. . When combustion occurs, the piston 128 is pushed down to the bottom dead center side by the combustion pressure. The linear motion between the top dead center and the bottom dead center of the piston 128 is converted into the rotational motion of the crankshaft 130 by the crank mechanism, and power is generated in the engine 150.

  Exhaust gas generated by combustion of the air-fuel mixture in the cylinder 162 flows from the exhaust port 160 to the exhaust pipe (1) 108 and flows into the three-way catalyst 120. Nitrogen oxide (NOx) contained in the inflowing exhaust gas is reduced in the three-way catalyst 120. Further, HC or CO contained in the inflowing exhaust gas is oxidized in the three-way catalyst 120. In the present embodiment, the three-way catalyst 120 is a catalyst that reduces NOx and oxidizes HC and CO, but may be any catalyst that purifies exhaust gas by at least an oxidation reaction.

  When the fuel is directly injected into the cylinder 162 by the fuel injection device 126 at the time of cold such as immediately after the engine 150 is started, the injected fuel becomes difficult to atomize. Therefore, the injected fuel may adhere to the piston 128. If the fuel adheres to the piston 128, the air-fuel ratio is lowered and an amount of fuel that produces the assumed torque is not supplied, so that an appropriate torque may not be obtained.

  Therefore, when the condition that the temperature of engine 150 is equal to or lower than a predetermined temperature is satisfied, ECU 100 has a fuel injection timing higher than the fuel injection timing when the temperature of engine 150 is higher than the predetermined temperature. The fuel injection device 126 is controlled so as to retard.

  Note that the temperature of the engine 150 is the temperature of the piston 128, and the ECU 100 may estimate the temperature of the piston 128 based on the coolant temperature, or may be a cylinder block or a cylinder head of the engine 150, for example. The temperature of the piston 128 may be estimated based on the temperature of the component.

  By retarding the fuel injection timing, the distance between the piston 128 and the fuel injection device 126 is increased, and fuel is injected at a position where the piston 128 is lower. As a result, the amount of fuel atomized increases as the amount of adhesion to the piston 128 decreases, so that a decrease in torque can be suppressed.

  However, since there is a limit to the suppression of fuel adhesion to the piston 128 due to the retard of the injection timing, there is a case where it is not possible to generate a torque equivalent to the normal time other than the cold time only by the injection timing. In particular, when the fuel atomized due to the delay of the injection timing contacts the valve, the fuel may adhere to the plug. For this reason, there is a possibility that sufficient torque is not generated.

  Accordingly, the present invention provides a condition that the ECU 100 is in a return state from the fuel cut control (hereinafter, referred to as a condition (1)) in addition to a condition regarding the temperature of the engine 150 (hereinafter referred to as a condition (1)). When the condition (2) is satisfied, the fuel injected into the cylinder of the engine 150 based on the detected coolant temperature and the detected intake air amount in addition to delaying the fuel injection timing However, it is characterized in that the fuel injection device 126 is controlled so as to be increased as compared with the case where the condition (2) is not satisfied.

  Specifically, the ECU 100 determines the fuel increase coefficient (hereinafter also referred to as an increase correction coefficient) Cf based on the coolant temperature Tw of the engine 150 and the integrated value Q of the intake air amount after the engine 150 is started. And the fuel injection device 126 is controlled so that the fuel injection amount is based on the determined increase correction coefficient Cf.

  FIG. 2 shows a functional block diagram of ECU 100 that is the control device for the internal combustion engine according to the present embodiment.

  ECU 100 includes an input interface (hereinafter referred to as an input I / F) 300, an arithmetic processing unit 400, a storage unit 500, and an output interface (hereinafter referred to as an output I / F) 600.

  The input I / F 300 receives a water temperature signal from the water temperature sensor 106, a throttle opening signal from the throttle position sensor 116, an engine speed signal from the crank position sensor 156, and an intake air amount signal from the air flow meter 190. Receiving and transmitting to the arithmetic processing unit 400.

  The arithmetic processing unit 400 includes a water temperature determination unit 402, an integrated value determination unit 404, an injection timing retardation control unit 406, an F / C return determination unit 408, a rotation speed determination unit 410, and a rotation change amount determination unit 412. A throttle opening degree determination unit 414, a correction coefficient setting unit 416, and an attenuation processing unit 418.

  Water temperature determination unit 402 determines whether or not cooling water temperature Tw based on a water temperature signal received from input I / F 300 is lower than a predetermined value A (0). Note that the water temperature determination unit (1) 402 may turn on the water temperature determination flag when the cooling water temperature Tw is equal to or less than a predetermined value A (0), for example.

  The integrated value determination unit 404 determines whether or not the integrated value Q of the intake air amount integrated every calculation cycle after the engine 150 is started is equal to or less than a predetermined value B (0). Note that the integrated value determination unit 404 may turn on the integrated value determination flag when the integrated value Q of the intake air amount is equal to or less than a predetermined value B (0).

  The injection timing retardation control unit 406 determines that the cooling water temperature Tw is equal to or less than a predetermined value A (0) and the integrated value Q of the intake air amount is equal to or less than a predetermined value B (0). Then, a map whose fuel injection timing is later than the normal map (hereinafter simply referred to as a retard side map) is selected, and the fuel injection device 126 is controlled based on the selected map. In addition, the injection timing retardation control unit 406 determines that the coolant temperature Tw is greater than a predetermined value A (0) or that the integrated value Q of the intake air amount is greater than a predetermined value B (0). If it is larger, the normal injection timing map is selected. In addition, the injection timing retard control unit 406 specifies the injection timing based on the selected map and the number of revolutions of the engine 150, and controls the fuel injection device 126 based on the specified injection timing.

  Note that the injection timing retard control unit 406 may select the retard side map when, for example, both the water temperature determination flag and the integrated value determination flag are on.

  The retard side map is a map that is set in advance so that the injection timing is retarded with respect to the same engine speed as compared to the normal injection timing map. Further, the map in which the injection timing is on the retard side and the map of the normal injection timing are adapted by experiments or the like. Note that a map in which the injection timing is on the retard side may be set based on a table or a mathematical expression instead of the map.

  The F / C return determination unit 408 determines whether or not the state of the engine 150 is a return state from the fuel cut control. The F / C return determination unit 408 determines that the state of the engine 150 is the fuel cut control when the execution condition is satisfied and is not satisfied based on the traveling state of the vehicle that is the execution condition of the fuel cut control of the engine 150. It is determined that it is a return state from.

  For example, when the F / C return determination unit 408 determines that the state of the engine 150 is a return state from the fuel cut control, the return determination flag may be turned on.

  Rotational speed determination unit 410 determines whether engine rotational speed NE based on the engine rotational speed signal received from input I / F 300 is equal to or smaller than a predetermined value C (0). Note that the rotational speed determination unit 410 may turn on the rotational speed determination flag when the engine rotational speed NE is equal to or less than a predetermined value C (0), for example.

  The rotation change amount determination unit 412 determines whether or not the change amount dNE of the engine speed NE is equal to or less than a predetermined value D (0). Note that the rotation change amount determination unit 412 may turn on the rotation change amount determination flag when the change amount dNE of the engine speed NE is equal to or less than a predetermined value D (0), for example. The change amount dNE may be a time change amount, a change amount for each calculation cycle, or a predetermined change amount for each calculation cycle.

  The throttle opening degree determination unit 414 determines whether or not the throttle opening degree TH based on the throttle opening degree signal received from the input I / F 300 is equal to or less than a predetermined value TH (0). The throttle opening degree determination unit 414 may turn on the throttle condition establishment flag when the throttle opening degree TH is equal to or less than a predetermined value TH (0), for example.

  The correction coefficient setting unit 416 includes a condition (1) that the state of the engine 150 is a return state from the fuel cut control, and a condition (2) that the cooling water temperature Tw is equal to or less than a predetermined value A (0). The condition (3) that the engine speed NE is equal to or less than a predetermined value C (0) and the condition that the amount of change dNE of the engine speed NE is equal to or less than a predetermined value D (0) (4 ), A condition (5) that the state of the engine 150 is within a predetermined time after it is determined that the engine 150 is in a return state from the fuel cut control, and a throttle opening TH is a predetermined value TH (0). ) When both of the following conditions (6) are satisfied, the increase correction coefficient Cf is calculated based on the integrated value Q of the intake air amount and the cooling water temperature Tw.

  The correction coefficient setting unit 416 sets the increase correction coefficient Cf based on the cooling water temperature Tw and the intake air amount, for example, using the table of FIG. As shown in FIG. 3, in the integrated value of the same intake air amount, the increase correction coefficient Cf is set to be smaller as the coolant temperature Tw is higher (that is, the increase correction coefficient Cf is lower as the coolant temperature Tw is lower). Further, at the same cooling water temperature, the increase correction coefficient Cf is set to be smaller as the integrated value Q of the intake air amount becomes larger (that is, the integrated value Q of the intake air amount becomes smaller). The increase correction coefficient Cf is set to increase as the value decreases.)

  Note that the increase correction coefficient Cf corresponding to the cooling water temperature and the intake air amount not shown in the table of FIG. 3 may be calculated by linear interpolation using the values shown in the table of FIG. 3, for example. Further, a map, a mathematical expression, or the like may be used instead of the table of FIG.

  The correction coefficient setting unit 416 sets the increase correction coefficient Cf to 1.0 when both of the conditions (1) to (5) are satisfied and the condition (6) is not satisfied. The increase may be stopped. In the present embodiment, the increase correction coefficient Cf is set to a value larger than 1.0 when increasing, and the fuel injection amount calculated based on the state of the engine 150 is multiplied by the increase correction coefficient Cf. When the fuel injection amount increased in this way is calculated and the increase is stopped, it is explained that 1.0 is set as the increase correction coefficient Cf. However, it is not particularly limited to such an increase mode.

  For example, the increase correction coefficient Cf is calculated by multiplying the increase correction coefficient Cf and the basic fuel injection amount calculated based on the state of the engine 150 when increasing the fuel amount. If the fuel injection amount increased by the sum of the correction amount and the basic fuel injection amount is calculated, 0.0 may be set as the increase correction coefficient Cf when stopping the increase.

  Further, the correction coefficient setting unit 416 has, for example, all of the return determination flag, the water temperature determination flag, the rotation speed determination flag, the rotation change amount determination flag, and the throttle condition satisfaction flag, and the return determination flag is turned on. When the elapsed time from the time is within a predetermined time, the increase correction coefficient Cf may be set based on the integrated value Q of the intake air amount and the cooling water temperature Tw. Alternatively, the correction coefficient setting unit 416, for example, when all of the return determination flag, the water temperature determination flag, the rotation speed determination flag, and the rotation change amount determination flag are on and the throttle condition establishment flag is off, The increase correction coefficient Cf may be set to 1.0 to stop the increase.

  The attenuation processing unit 418 performs an attenuation process on the increase correction coefficient Cf when any one of the conditions (1) to (5) is not satisfied. The attenuation process is a process of decreasing the increase correction coefficient Cf with time. For example, the increase correction coefficient Cf may be attenuated by a predetermined value every time a predetermined time elapses.

  In the present embodiment, the water temperature determination unit 402, the integrated value determination unit 404, the injection timing retardation control unit 406, the F / C return determination unit 408, the rotation speed determination unit 410, and the rotation change amount determination The unit 412, the throttle opening degree determination unit 414, the correction coefficient setting unit 416, and the attenuation processing unit 418 are all realized by the CPU that is the arithmetic processing unit 400 executing a program stored in the storage unit 500. Although described as functioning as software, it may be realized by hardware. Such a program is recorded on a storage medium and mounted on the vehicle.

  Various information, programs, threshold values, maps, and the like are stored in the storage unit 500, and data is read or stored by the arithmetic processing unit 400 as necessary.

  Hereinafter, with reference to FIG. 4, a control structure of a program for retarding the injection timing according to the temperature of engine 150, executed by ECU 100, which is the control device for the internal combustion engine according to the present embodiment, will be described.

  In step (hereinafter, step is referred to as S) 100, ECU 100 determines whether or not coolant temperature Tw of engine 150 is equal to or lower than a predetermined value A (0). If cooling water temperature Tw is equal to or lower than predetermined value A (0) (YES in S100), the process proceeds to S102. If not (NO in S100), the process proceeds to S106.

  In S102, ECU 100 determines whether or not integrated value Q of the intake air amount is equal to or less than a predetermined value B (0). If integrated value Q of the intake air amount is equal to or smaller than a predetermined value B (0) (YES in S102), the process proceeds to S104. If not (NO in S102), the process proceeds to S106.

  In S104, ECU 100 selects the retard side map. In S106, ECU 100 selects the normal map.

  Next, a control structure of a program for calculating the increase correction coefficient Cf, which is executed by the ECU 100 that is the control device for the internal combustion engine according to the present embodiment, will be described with reference to FIG.

  In S200, ECU 100 determines whether or not the state of engine 150 is the return state from the fuel cut control. If the state of engine 150 is the return state from the fuel cut control (YES in S200), the process proceeds to S202. If not (NO in S200), the process proceeds to S216.

  In S202, ECU 100 determines whether or not cooling water temperature Tw is equal to or lower than a predetermined value A (0). If cooling water temperature Tw is equal to or lower than predetermined value A (0) (YES in S202), the process proceeds to S204. If not (NO in S202), the process proceeds to S216.

  In S204, ECU 100 determines whether engine speed NE is equal to or smaller than a predetermined value C (0). If engine speed NE is equal to or smaller than a predetermined value C (0) (YES in S204), the process proceeds to S206. If not (NO in S204), the process proceeds to S216.

  In S206, ECU 100 determines whether or not change amount dNE of engine speed NE is equal to or smaller than a predetermined value D (0). If variation dNE of engine speed NE is equal to or smaller than a predetermined value D (0) (YES in S206), the process proceeds to S208. If not (NO in S206), the process proceeds to S216.

  In S208, ECU 100 determines whether or not a predetermined time has elapsed since it was determined that the state of engine 150 is the return state from the fuel cut control. If it is determined that the state of engine 150 is the return state from the fuel cut control and a predetermined time has elapsed (YES in S208), the process proceeds to S216. If not (NO in S208), the process proceeds to S210.

  In S210, ECU 100 determines whether throttle opening degree TH is equal to or smaller than a predetermined value TH (0). If throttle opening TH is equal to or smaller than predetermined value TH (0) (YES in S210), the process proceeds to S212. If not (NO in S210), the process proceeds to S214.

  In S212, ECU 100 calculates an increase correction coefficient Cf based on cooling water temperature Tw and intake air amount integrated value Q. In S214, ECU 100 sets 1.0 as the increase correction coefficient Cf. In S216, ECU 100 performs an attenuation process for increase correction coefficient Cf.

  The operation of ECU 100 serving as the control device for the internal combustion engine according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIGS.

<Injection timing retard control>
For example, it is assumed that the engine 150 starts when it is cold. After engine 150 is started, cooling water temperature Tw is equal to or lower than predetermined value A (0) (YES in S100), and integrated value Q of the intake air amount is equal to or lower than predetermined value B (0). If it is (YES in S102), the retard side map is selected (S104). Therefore, the fuel injection timing other than the cold time (that is, the coolant temperature Tw is greater than a predetermined value A (0) or the integrated value Q of the intake air amount is a predetermined value. The fuel injection timing is set to be retarded with respect to the same engine speed than the fuel injection timing in the case of greater than B (0).

  On the other hand, the warm-up of engine 150 proceeds and cooling water temperature Tw is greater than a predetermined value A (0) (NO in S100), or integrated value Q of the intake air amount is predetermined. If the value is larger than value B (0) (NO in S102), the normal map is selected (S106).

<Fuel increase control: Part 1>
As shown in FIG. 6, for example, when the vehicle is in a stopped state, after the engine 150 is started and the driver erroneously selects the N position when starting the vehicle, the accelerator pedal is depressed. Therefore, it is assumed that the throttle opening TH is TH (1) and the engine speed NE is NE (0).

  When the driver switches the shift position from the N position to the D position at time T (0), the fuel cut occurs when the engine speed NE is equal to or higher than a predetermined speed that satisfies the fuel cut control execution condition. The flag is turned on and fuel cut control is performed.

  In this embodiment, the case where the fuel cut control is returned from the N position to the D position will be described. However, the present embodiment is particularly limited to the case where the fuel cut control is returned from the N position to the D position. For example, the same applies when returning from fuel cut control during deceleration.

  When the driver loosens the accelerator pedal at time T (1), the throttle opening TH starts to decrease. As the throttle opening TH decreases, the engine speed NE decreases. Therefore, the amount of change dNE of the engine speed NE changes in the negative direction (decreasing direction of the speed).

  Further, at time T (2), when the throttle opening TH becomes equal to or smaller than a predetermined value TH (0), the throttle condition satisfaction flag is turned on and the fuel cut flag is turned off. Determination flag is turned on (YES in S200).

  At time T (3), cooling water temperature Tw is equal to or lower than predetermined value A (0) (YES in S202), and engine speed NE is equal to or lower than predetermined value C (0). (YES in S204), change amount dNE of engine speed NE is equal to or smaller than a predetermined value D (0) (YES in S206), and the state of engine 150 is changed from the fuel cut control. If the predetermined time has not elapsed since the return state has been reached (NO in S208) and the throttle opening TH is equal to or smaller than the predetermined value TH (0) (YES in S210), the condition ( 1)-(6) The establishment flag is turned on, and the increase correction coefficient Cf is calculated as F (0) based on the coolant temperature Tw and the integrated value Q of the intake air amount (S212).

  Since the amount of fuel supplied into the cylinder is increased by the fuel injection control based on the calculated increase correction coefficient Cf, the air-fuel ratio of the air-fuel mixture in the combustion chamber becomes rich. Therefore, a desired torque is generated.

  After the time T (3), when the degree of decrease in the engine speed NE becomes smaller, the change amount dNE of the engine speed NE approaches zero.

  For example, when change amount dNE of engine speed NE becomes greater than predetermined value D (0) at time T (4) (NO in S206), the condition (1)-(6) satisfaction flag is set. The signal is turned off and the attenuation process is started (S216). Therefore, the increase correction coefficient Cf decreases with time. That is, the degree of increase in the fuel injection amount decreases.

  At time T (5) after a predetermined time has elapsed from time T (2), the F / C return determination flag is turned off (NO in S200). In this case, the attenuation process for the increase correction coefficient Cf is continued (S216).

<Fuel increase control: Part 2>
As shown in FIG. 7, for example, when the vehicle is in a stopped state, after the engine 150 is started and the driver erroneously selects the N position when starting the vehicle, the accelerator pedal is depressed. Therefore, it is assumed that the throttle opening TH is TH (1) and the engine speed NE is NE (0).

  The operation of ECU 100 from time T (0) to time T (3) in FIG. 7 is substantially the same as the operation of ECU 100 from time T (0) to time T (3) in FIG. . Therefore, detailed description thereof will not be repeated.

  After the time T (3), when the degree of decrease in the engine speed NE becomes smaller, the change amount dNE of the engine speed NE approaches zero.

  When the driver depresses the accelerator pedal at time T (6) and the throttle opening TH rises to TH (2) greater than a predetermined value TH (0) (NO in S210), the throttle condition is satisfied. Since the flag is turned off, 1.0 is set as the increase correction coefficient Cf, and the increase is stopped (S214).

  Even when the throttle opening TH becomes equal to or less than a predetermined value TH (0) at time T (7), the condition (1) is reached before the time T (8) when the fuel cut return flag is turned off. -Since all of the conditions (6) are not satisfied, the fuel injection amount is not increased.

<Fuel increase control: Part 3>
For example, it is assumed that the throttle opening TH is zero and the engine speed is NE (1). In this case, when the driver changes the shift position from the N position to the D position, when the engine speed NE is equal to or higher than a predetermined speed that satisfies the execution condition of the fuel cut control, the time T ′ (0 ), The fuel cut flag is turned on, and fuel cut control is performed.

  At time T ′ (1), when the engine speed NE falls below a predetermined speed that satisfies the conditions for executing the fuel cut control, the fuel cut flag is turned off and the fuel cut return determination flag is turned on. (YES at S200).

  Further, cooling water temperature Tw is equal to or lower than a predetermined value A (0) (YES at S202), and engine speed NE is equal to or lower than a predetermined value C (0) (YES at S204). Further, the amount of change dNE of engine speed NE is equal to or smaller than a predetermined value D (0) (YES in S206), and is determined in advance after the state of engine 150 has returned from the fuel cut control. If the predetermined time has not elapsed (NO in S208) and throttle opening TH is equal to or smaller than a predetermined value TH (0) (YES in S210), a condition (1)-(6) establishment flag Is turned on, and F (0) is calculated as the increase correction coefficient Cf based on the coolant temperature Tw and the integrated value Q of the intake air amount (S212).

  When the driver depresses the accelerator pedal at time T ′ (2), the throttle opening TH increases to TH (3). Therefore, when throttle opening degree TH becomes larger than a predetermined value TH (0) (NO in S210), the throttle condition establishment flag is turned off. Therefore, the fuel injection amount increase is stopped by setting 1.0 as the increase correction coefficient Cf (S214).

  When the driver relaxes the depression of the accelerator pedal at time T ′ (3) and the throttle opening TH becomes equal to or smaller than a predetermined value TH (0) at time T ′ (4), a throttle condition establishment flag is set. Is turned off.

  When both of the conditions (1) to (6) are satisfied again at the time T ′ (5), the condition (1) to (6) satisfaction flag is turned on, and the cooling water temperature Tw and the intake air amount are set. Based on the integrated value Q, F (0) is calculated as the increase correction coefficient Cf (S212).

  At time T ′ (6), when a predetermined time has elapsed since the state of engine 150 has returned from the fuel cut control (YES in S208), the condition (1)-(6) establishment flag Is turned off, attenuation processing is performed (S216).

  As described above, according to the control apparatus for an internal combustion engine according to the present embodiment, when any of the conditions (1) to (6) is satisfied, in addition to delaying the fuel injection timing, Since the fuel injection device is controlled based on the integrated value of the intake air amount so that the amount of fuel injected into the cylinders of the engine 150 is increased as compared with the case where the conditions (1) to (6) are not satisfied, Even if the fuel injection timing is delayed to suppress fuel adhesion, a further insufficient torque can be compensated for by an increase in fuel. Further, by increasing the amount of fuel based on the cooling water temperature and the intake air amount, it is possible to increase the amount of fuel corresponding to the state of the engine. Therefore, it is possible to provide a control device and a control method for an internal combustion engine that expresses an appropriate torque when the direct injection internal combustion engine is cold.

  Further, when any one of the conditions (1) to (5) is not satisfied, an increase in the fuel injection amount is decreased with time, so that an appropriate amount of fuel increase can be obtained at an appropriate time. Can be implemented. Thereby, an appropriate torque can be expressed in the engine during cold weather.

  Furthermore, when only the condition regarding the throttle opening TH is not satisfied among the conditions (1) to (6), the fuel increase is stopped, so that the unnecessary fuel increase is stopped and the emission and the fuel consumption are deteriorated. Can be prevented.

  In particular, in the case of an engine equipped with an in-cylinder fuel injection device and a port injection device that injects fuel into the intake port, the return from the fuel cut when the shift position is changed from the N position to the D position. At times, the fuel is directly injected into the cylinder by the in-cylinder fuel injection device, so that the present invention can be applied to generate an appropriate torque in a state where fuel adhesion occurs when the engine is cold. The effect that it can be obtained.

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

It is a figure which shows the structure of the engine mounted in a vehicle. It is a functional block diagram of ECU which is a control device of an internal combustion engine concerning this embodiment. It is a figure which shows the relationship between the integrated value of cooling water temperature, the amount of intake air, and an increase correction coefficient. It is a flowchart (the 1) which shows the control structure of the program performed by ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment. It is a flowchart (the 2) which shows the control structure of the program performed with ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment. It is a timing chart (the 1) which shows operation | movement of ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment. It is a timing chart (the 2) which shows operation | movement of ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment. 6 is a timing chart (No. 3) showing the operation of the ECU which is the control device for the internal combustion engine according to the present embodiment.

Explanation of symbols

  102 Oxygen sensor, 104 Intake temperature sensor, 106 Water temperature sensor, 110 Intake pipe, 112 Throttle valve, 114 Throttle motor, 116 Throttle position sensor, 118 Air cleaner, 120 Three-way catalyst, 122 Piston rod, 124 Cylinder block, 126 Fuel injection device , 128 piston, 130 crankshaft, 132 crankcase, 148 surge tank, 150 engine, 152 intake system, 154 exhaust system, 156 crank position sensor, 158 intake port, 160 exhaust port, 162 cylinder, 166 three-way catalyst, 172 intake Valve, 174 Exhaust valve, 176 Spark plug, 190 Air flow meter, 200 Air-fuel ratio sensor, 300 Input I / F, 400 Arithmetic processing unit, 40 Water temperature determination unit, 404 integrated value determination unit, 406 injection timing retardation control unit, 408 return determination unit, 410 rotation number determination unit, 412 rotation change amount determination unit, 414 throttle opening determination unit, 416 correction coefficient setting unit, 418 Attenuation processing unit, 500 storage unit, 600 output I / F.

Claims (14)

A control device for an internal combustion engine mounted on a vehicle, the internal combustion engine including a fuel injection device that injects fuel directly into at least a cylinder,
Temperature detecting means for detecting the temperature of the internal combustion engine;
An intake air amount detection means for detecting the intake air amount of the internal combustion engine;
When the first condition that the temperature of the internal combustion engine is equal to or lower than a predetermined temperature is satisfied, the fuel injection device is controlled to delay the fuel injection timing as compared with the case where the first condition is not satisfied. and a injection control means for,
In addition to the first condition, the injection control means delays the fuel injection timing when a second condition that the state of the internal combustion engine is a return state from fuel cut control is satisfied. In addition, on the basis of the temperature of the internal combustion engine and the intake air amount, the fuel injection amount is increased so that the fuel injection amount injected into the cylinder of the internal combustion engine is increased as compared with the case where the second condition is not satisfied. Control the device ,
The controller is
A rotational speed detection means for detecting the rotational speed of the internal combustion engine;
Means for detecting the throttle opening of the internal combustion engine,
In addition to the first condition and the second condition, the injection control means includes a third condition that the detected rotation speed is equal to or less than a predetermined rotation speed, and a change amount of the rotation speed. A fourth condition that the amount of change is equal to or less than a predetermined amount of change; a fifth condition that an elapsed time from when the second condition is satisfied is within a predetermined time; and the detected throttle When the sixth condition that the opening degree is equal to or less than a predetermined opening degree is satisfied, the fuel injection amount is greater than the case where any one of the first condition to the sixth condition is not satisfied. A control device for an internal combustion engine, which controls the fuel injection device so as to increase the amount of fuel . The temperature detecting means detects a cooling water temperature of the internal combustion engine,
The injection control means includes
Determining means for determining an increase coefficient based on a cooling water temperature of the internal combustion engine and an integrated value of the intake air amount after the internal combustion engine is started;
The control device for an internal combustion engine according to claim 1, further comprising means for controlling the fuel injection device so as to obtain a fuel injection amount based on the increase coefficient. The determining means includes
Means for determining the increase coefficient such that the lower the cooling water temperature is, the greater the degree of increase is than when the cooling water temperature is high;
The control device for an internal combustion engine according to claim 2, further comprising means for determining the increase coefficient such that the smaller the integrated value is, the greater the degree of increase is than when the integrated value is large. The fuel injection device is configured to reduce the degree of increase in the fuel injection amount with the passage of time when any one of the first condition to the fifth condition is not satisfied. The control device for an internal combustion engine according to any one of claims 1 to 3, which controls the engine. The injection control means stops the increase in the fuel when any of the first to fifth conditions is satisfied and when the sixth condition is not satisfied. controlling said fuel injector, the control apparatus for an internal combustion engine according to any one of claims 1 to 4. The controller is
Means for detecting a running state of the vehicle as an execution condition of fuel cut control of the internal combustion engine;
Wherein based on the detected running condition, after the execution condition is satisfied, if it becomes satisfied, and means for determining that said second condition is satisfied, according to claim 1 to 5 The control device for an internal combustion engine according to any one of the above. The control device for an internal combustion engine according to any one of claims 1 to 6 , wherein an automatic transmission coupled to an output shaft of the internal combustion engine is mounted on the vehicle. A control method for an internal combustion engine mounted on a vehicle, the internal combustion engine including a fuel injection device that injects fuel directly into at least a cylinder,
A temperature detecting step for detecting the temperature of the internal combustion engine;
An intake air amount detection step for detecting an intake air amount of the internal combustion engine;
When the first condition that the temperature of the internal combustion engine is equal to or lower than a predetermined temperature is satisfied, the fuel injection device is controlled to delay the fuel injection timing as compared with the case where the first condition is not satisfied. and a injection control step for,
In addition to the first condition, the injection control step delays the fuel injection timing when a second condition that the state of the internal combustion engine is a return state from fuel cut control is satisfied. In addition, the fuel injection device is configured to increase the fuel injection amount injected into the cylinder of the internal combustion engine based on the temperature of the internal combustion engine and the intake air amount as compared with the case where the second condition is not satisfied. controls,
The control method is:
A rotational speed detection step for detecting the rotational speed of the internal combustion engine;
Detecting the throttle opening of the internal combustion engine,
In the injection control step, in addition to the first condition and the second condition, a third condition that the detected rotational speed is equal to or less than a predetermined rotational speed, and a change amount of the rotational speed is A fourth condition that the amount of change is equal to or less than a predetermined amount of change; a fifth condition that an elapsed time from when the second condition is satisfied is within a predetermined time; and the detected throttle When the sixth condition that the opening degree is equal to or less than a predetermined opening degree is satisfied, the fuel injection amount is greater than the case where any one of the first condition to the sixth condition is not satisfied. A control method for an internal combustion engine, wherein the fuel injection device is controlled to increase the amount of fuel. The temperature detecting step detects a cooling water temperature of the internal combustion engine,
The injection control step includes
A determination step of determining an increase coefficient based on a cooling water temperature of the internal combustion engine and an integrated value of the intake air amount after the internal combustion engine is started;
The method for controlling an internal combustion engine according to claim 8 , further comprising: controlling the fuel injection device so as to obtain a fuel injection amount based on the increase coefficient. The determining step includes
Determining the increase factor such that the lower the cooling water temperature is, the greater the degree of increase than when the cooling water temperature is high;
The internal combustion engine control method according to claim 9 , further comprising a step of determining the increase coefficient such that the smaller the integrated value, the greater the degree of increase than when the integrated value is large. In the injection control step, when any one of the first condition to the fifth condition is not established, the fuel injection device is configured to decrease the degree of increase in the fuel injection amount with time. The method for controlling an internal combustion engine according to any one of claims 8 to 10, wherein the control is performed. In the injection control step, the fuel increase is stopped when any of the first condition to the fifth condition is satisfied and when the sixth condition is not satisfied. The method for controlling an internal combustion engine according to any one of claims 8 to 11 , wherein the fuel injection device is controlled. The control method is:
Detecting a running state of the vehicle that is an execution condition of fuel cut control of the internal combustion engine;
Wherein based on the detected running condition, after the execution condition is satisfied, if it becomes satisfied, further comprising a step of determining that the second condition is satisfied, any claim 8 to 12 a control method for an internal combustion engine according to any one of claims. The method for controlling an internal combustion engine according to any one of claims 8 to 13, wherein the vehicle is equipped with an automatic transmission coupled to an output shaft of the internal combustion engine.

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