JP5616264B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device, and more particularly to an engine control device that controls a fuel injection amount of an engine of a moving body such as a vehicle.

  In recent years, in a moving body such as a vehicle, in order to control the fuel supply amount to the engine in a mode with a high degree of freedom in accordance with the operation of the accelerator operation member while avoiding a complicated mechanical configuration. 2. Description of the Related Art An engine control device having a fuel injection control mechanism that injects fuel from an injector while electronically controlling the amount of fuel supplied to the engine has been adopted.

  Further, in such an engine, when a moving body such as a vehicle is located at a high altitude, the amount of fuel in the air-fuel mixture becomes relatively excessive as the atmospheric pressure decreases and the intake air amount decreases. Changes to a rich state unnecessarily. In this way, when the air-fuel mixture becomes unnecessarily rich, not only changes in the drivability of such vehicles, but also unnecessary fuel consumption and unnecessary changes in the component ratio of the exhaust gas chemicals can occur. There is sex.

  Therefore, even when the atmospheric pressure decreases according to the altitude of a moving body such as a vehicle and the intake air amount decreases, the same air-fuel ratio as when the vehicle is located in a lowland is realized with a simple configuration. It is intended to provide the fuel injection amount according to the actual altitude and atmospheric pressure by using the existing pressure sensor without adding an unnecessary pressure sensor for detecting the atmospheric pressure. A configuration of the engine control apparatus has been proposed.

  Under such circumstances, Patent Document 1 relates to an electronically controlled fuel injection device, which includes an engine speed detection sensor, a throttle sensor, and a mass air amount sensor that detects an intake air amount of the engine, and the previous engine parameter and the current engine parameter. And a configuration for detecting altitude without using an atmospheric pressure sensor.

  Patent document 2 relates to an engine fuel control device, and discloses a configuration that includes a pressure sensor that detects an intake manifold pressure of the engine as an absolute value, and uses the detected pressure of the pressure sensor as an atmospheric pressure before engine rotation. .

Japanese Patent No. 02936749 Japanese Patent Publication No. 07-037773

  However, according to the study of the present inventor, according to the configuration disclosed in Patent Document 1, it is necessary to provide the mass air amount sensor itself for detecting the intake air amount of the engine, so that the configuration is complicated. It is necessary to prepare various map data in order to compare engine parameters, the amount of data to be prepared as a whole control device is greatly increased, the configuration becomes complicated, and it is difficult to realize cost reduction The tendency to become strong.

  Further, according to the configuration disclosed in Patent Document 2, since it is necessary to provide the pressure sensor itself that detects the intake manifold pressure of the engine with an absolute value, the configuration is complicated and it is difficult to realize cost reduction. There is a strong tendency to become.

  In other words, engine control that can achieve good startability and suppress fuel injection with unnecessary fuel amount while reducing the data volume required for high altitude correction of fuel injection amount without using various pressure sensors The current situation is expected to provide equipment.

  The present invention has been made through the above-described studies, and has good startability while reducing the data volume necessary for high altitude correction of the fuel injection amount without using a pressure sensor such as an atmospheric pressure sensor or an intake pressure sensor. And an engine control device capable of suppressing fuel injection with an unnecessary fuel amount.

  In order to achieve the above object, the present invention considers a predetermined first air density correction coefficient corrected for high altitude, and determines the initial fuel injection amount at the start of the engine as a basic fuel according to the engine temperature. An initial injection amount calculation unit that calculates an initial fuel injection amount that is smaller than an injection amount; a fuel increase control unit that sequentially increases the initial fuel injection amount by sequentially increasing the first air density correction coefficient; and In consideration of the air density correction coefficient sequentially increased by the fuel increase control unit after the complete explosion of the engine, which corresponds to the engine speed exceeding the complete explosion reference value after starting the engine, An engine control apparatus according to a first aspect, comprising: a post-combustion injection amount calculation unit that calculates a fuel injection amount after a complete explosion of the engine.

  In addition to the first aspect, the present invention takes into consideration the air density correction coefficient sequentially increased by the fuel increase control unit after the complete explosion of the engine, and sets the second air density correction coefficient. An air density correction coefficient calculation unit for calculating, and the post-combustion injection amount calculation unit calculates a fuel injection amount after the complete explosion of the engine in consideration of the second air density correction coefficient. The second aspect.

  Further, according to the present invention, in addition to the second aspect, the air density correction coefficient calculation unit activates an oxygen sensor attached to an exhaust system of the engine and responds to an output value from the oxygen sensor. Until the oxygen sensor feedback correction coefficient converges, a third aspect is to set the air density correction coefficient sequentially increased by the fuel increase control unit to the second air density correction coefficient.

  In addition to the third aspect of the present invention, the air density correction coefficient calculation unit is configured to detect a deviation of the oxygen sensor feedback correction coefficient after the oxygen sensor is activated and the oxygen sensor feedback correction coefficient converges. In the fourth aspect, the second air density correction coefficient is calculated in consideration of the oxygen sensor feedback correction coefficient when the air pressure becomes equal to or greater than a predetermined value.

  According to the engine control apparatus of the first aspect of the present invention, the initial fuel injection amount at the start of the engine is determined according to the engine temperature in consideration of the predetermined first air density correction coefficient corrected for the high altitude. An initial injection amount calculation unit that calculates an initial fuel injection amount that is smaller than the basic fuel injection amount, a fuel increase control unit that sequentially increases the initial fuel injection amount by sequentially increasing the first air density correction coefficient, After the engine completes the engine corresponding to the engine speed exceeding the complete explosion reference value after the engine is started, the engine complete explosion is considered in consideration of the air density correction factor that has been sequentially increased by the fuel increase control unit. The post-explosion post-combustion injection amount calculation unit for calculating the subsequent fuel injection amount, and without using a pressure sensor such as an atmospheric pressure sensor or an intake pressure sensor, the data capacity necessary for high altitude correction of the fuel injection amount While reducing, it is possible to achieve good startability, it is possible to suppress the fuel injection in unnecessary fuel amount.

  Further, according to the engine control apparatus of the second aspect of the present invention, the second air density correction coefficient is taken into consideration after the complete explosion of the engine, taking into account the air density correction coefficient sequentially increased by the fuel increase control unit. The post-explosion post-combustion injection amount calculation unit further calculates the fuel injection amount after the complete explosion of the engine in consideration of the second air density correction coefficient. Thus, it is possible to realize a reliable startability and more reliably suppress fuel injection with an unnecessary fuel amount after the complete explosion of the engine.

  Moreover, according to the engine control apparatus according to the third aspect of the present invention, the air density correction coefficient calculation unit activates the oxygen sensor attached to the exhaust system of the engine and responds to the output value from the oxygen sensor. Until the oxygen sensor feedback correction coefficient converges, by setting the air density correction coefficient sequentially increased by the fuel increase control unit to the second air density correction coefficient, good startability can be realized, and the oxygen sensor The fuel injection with an unnecessary fuel amount after the complete explosion of the engine can be suppressed in accordance with the operation state.

  Further, according to the engine control apparatus of the fourth aspect of the present invention, after the air density correction coefficient calculation unit has activated the oxygen sensor and the oxygen sensor feedback correction coefficient has converged, the deviation of the oxygen sensor feedback correction coefficient is increased. When the value exceeds the predetermined value, the second air density correction coefficient is calculated in consideration of the oxygen sensor feedback correction coefficient, thereby realizing good startability and depending on the operating state of the oxygen sensor. Fuel injection with an unnecessary fuel amount after complete explosion of the engine can be suppressed more reliably.

FIG. 1 is a schematic diagram showing the configuration of an engine control device and an engine to which the engine control device according to an embodiment of the present invention is applied. FIG. 2 is a flowchart showing a control process of the engine control apparatus in the present embodiment. Specifically, FIG. 2A is a flowchart showing the overall flow of the engine control process, and FIG. 2B is a calculation of the fuel injection amount at start-up in the engine control process shown in FIG. It is a flowchart which shows the flow of a process. FIG. 3 is a flowchart showing a flow of post-combustion air density correction coefficient calculation processing in the engine control processing shown in FIG. FIG. 4 is a timing chart for explaining a specific example of the engine control process in the present embodiment. FIG. 4A is a timing chart of air density correction coefficients MAS and MA and oxygen sensor feedback correction coefficients MG and MGR. FIG. 4B shows a timing chart of the engine speed NE and the fuel injection amounts TIS, TI.

  Hereinafter, an engine control apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[Engine configuration]
First, a configuration of an engine to which an engine control device according to an embodiment of the present invention is applied will be described in detail with reference to FIG.

  FIG. 1 is a schematic diagram showing a configuration of an engine control device and an engine to which the engine control device is applied in the present embodiment.

  As shown in FIG. 1, an engine 1 is an internal combustion engine such as a gasoline engine mounted on a moving body such as a vehicle (not shown), and typically includes a cylinder block 2 having a plurality of cylinders. For convenience of explanation, only one cylinder is shown in the figure.

  In the side wall of the cylinder block 2, a cooling water passage for cooling the engine 1 flows and a cooling water passage (not shown) is formed. A water temperature sensor 3 is provided in the cooling water passage. The water temperature sensor 3 detects the temperature of the cooling water flowing through the cooling water passage, that is, the temperature of the engine 1, and outputs the detected value to the engine control device 100 as a voltage signal. When the engine 1 is air-cooled, an appropriate temperature sensor that detects the temperature of the engine 1 can be provided instead of the water temperature sensor 3.

  A piston 4 is disposed inside the cylinder block 2. The piston 4 is connected to the crank 6 via a connecting rod 5. A crank angle sensor 7 is provided in the vicinity of the crank 6. Crank angle sensor 7 detects the rotation angle of crank 6 and outputs the detected value to engine control device 100 as a voltage signal.

  A cylinder head 8 is mounted on the upper portion of the cylinder block 2. A space between the piston 4 and the cylinder head 8 defines a combustion chamber 9.

  The cylinder head 8 is provided with a spark plug 10 that ignites the air-fuel mixture in the combustion chamber 9. The ignition operation of the spark plug 10 is controlled by the engine control device 100 controlling energization to an ignition coil (not shown).

  The cylinder head 8 is provided with an intake passage 11 that communicates with the combustion chamber 9. An intake valve 12 is provided at a connection portion between the combustion chamber 9 and the intake passage 11. The intake passage 11 is provided with an injector 13 for injecting fuel therein. Further, a throttle valve 14 is provided in the intake passage 11 on the upstream side of the injector 13. A throttle opening sensor 15 is provided in the vicinity of the throttle valve 14. The throttle opening sensor 15 detects the opening of the throttle valve 14 and outputs the detected value to the engine control device 100 as a voltage signal. The injector 13 may be provided in the cylinder head 8 so as to inject fuel directly into the combustion chamber 9.

  The cylinder head 8 is provided with an exhaust passage 16 communicating with the combustion chamber 9. An exhaust valve 17 is provided at a connection portion between the combustion chamber 9 and the exhaust passage 16. The exhaust passage 16 is provided with a catalytic converter 18 for purifying the exhaust gas of the engine 1. An oxygen sensor 19 is provided upstream of the catalytic converter 18 in the exhaust passage 16. The oxygen sensor 19 detects the oxygen concentration in the exhaust gas of the engine 1 and outputs the detected value to the engine control device 100 as a voltage signal.

[Configuration of engine control unit]
Next, the configuration of the engine control apparatus according to the embodiment of the present invention will be described in detail with reference to FIG.

As shown in FIG. 1, the engine control apparatus 100 is typically configured as an electronic control unit (ECU) that includes a microcomputer and performs arithmetic processing, and is mounted on a moving body such as a vehicle. Operates with power supplied from the battery. The engine control apparatus 100 includes a crank angle signal detection unit 101, a throttle valve opening detection unit 102, an oxygen sensor output detection unit 103, an engine temperature detection unit 104, a memory 105, an engine speed calculation unit 106, and an air density correction coefficient calculation. Unit 107, fuel injection amount control unit 108 and ignition timing control unit 109. It should be noted that such a crank angle signal detection unit 101, throttle valve opening detection unit 102, oxygen sensor output detection unit 103, engine temperature detection unit 104, engine speed calculation unit 106, air density correction coefficient calculation unit 107, fuel injection The quantity control unit 108 and the ignition timing control unit 109 are respectively shown as functional blocks for arithmetic processing. In addition, the air density correction coefficient calculation unit 107 may be provided as a functional block inside the fuel injection amount control unit 108.

  Specifically, the crank angle signal detection unit 101 reads the voltage signal output from the crank angle sensor 7, detects the rotation angle of the crank 6 from the voltage signal, and uses the detected value as the engine speed calculation unit 106. Output to. The throttle valve opening detection unit 102 detects the opening of the throttle valve 14 based on the voltage signal output from the throttle opening sensor 15 and outputs the detected value to the fuel injection amount control unit 108.

  The oxygen sensor output detection unit 103 reads the voltage signal output from the oxygen sensor 19, detects the oxygen sensor output voltage VG from the voltage signal, and based on each of the oxygen sensor output voltage VG, the oxygen sensor output voltage VG. Activation determination, oxygen sensor feedback correction coefficient MG calculation, oxygen sensor feedback correction coefficient MG convergence determination, and oxygen sensor feedback correction coefficient MG deviation determination are executed, and the calculated value and determination result are calculated as an air density correction coefficient. Output to the unit 107. Note that the oxygen sensor output detection unit 103 may have only a function of reading the voltage signal output from the oxygen sensor 19 and detecting the oxygen sensor output voltage VG. Activation determination, oxygen sensor feedback correction coefficient MG calculation, oxygen sensor feedback correction coefficient MG convergence determination, and oxygen sensor feedback correction coefficient MG deviation determination are executed, and the calculated value and determination result are calculated as an air density correction coefficient. A calculation determination function block to be output to the unit 107 may be provided.

  The engine temperature detection unit 104 reads the voltage signal output from the water temperature sensor 3, detects the temperature of the engine 1 from the voltage signal, and outputs the detected value to the fuel injection amount control unit 108.

  The memory 105 includes various memories such as a ROM (Read Only Memory) 105a, a RAM (Random Access Memory) 105b, and an EEPROM (Electronically Erasable and Programmable Read Only Memory) 105c. The ROM 105a stores various data such as various control programs for controlling the engine 1 and control data for controlling the engine 1. As various control data, for example, basic fuel injection amount map data corresponding to the engine speed and throttle opening, basic fuel injection amount map data corresponding to the engine temperature, and the complete explosion state of the engine 1 are determined. For example, the value of the reference rotational speed (complete explosion reference value) and the value of the air density correction coefficient MAS (first air density correction correction coefficient) corrected for high altitude. The various data stored in the RAM 105b and the EEPROM 105c include data of various calculated values calculated by the engine control device 100, values of various flags set by the engine control device 100, and the like. The memory 105 may be provided separately outside the engine control apparatus 100.

  The engine speed calculation unit 106 calculates the rotation speed of the engine 1 based on the detected value of the rotation angle of the crank 6 output from the crank angle signal detection unit 101, and uses the calculated value as the fuel injection amount control unit 108 and the ignition. Each is output to the timing control unit 109.

  The air density correction coefficient calculation unit 107 mainly uses the various output values such as the calculated value and determination result from the oxygen sensor output detection unit 103 and various data stored in the memory 105 to complete the complete explosion of the engine 1. A post-explosion post-explosion air density correction coefficient MA (second air density correction coefficient) which is a later air density correction coefficient is calculated, and the calculated values are output to the fuel injection amount control unit 108 and the ignition timing control unit 109, respectively.

The fuel injection amount control unit 108 includes an initial injection amount calculation unit 108a, a fuel increase control unit 108b, and a post-completion injection amount calculation unit 108c as functional blocks for the arithmetic processing, and the engine 1 is started and reaches a complete explosion state. The fuel injection amount of the injector 13 is controlled through the process of maintaining the complete explosion state. The initial injection amount calculation unit 108a and the fuel increase control unit 108b are configured so that the fuel injection amount control unit 108 starts the initial fuel injection amount TISI from the injector 13 and starts when the engine 1 is started and complete explosion occurs. The post-explosion post-combustion injection amount calculation unit 108c functions as a fuel injection amount TIS after the complete explosion of the engine 1, and the fuel injection amount control unit 108 performs fuel injection after the engine complete explosion from the injector 13. It functions when fuel is ejected by the amount TI.

  The ignition timing control unit 109 controls the ignition operation of the spark plug 10 by controlling the energization state of an ignition coil (not shown).

[Engine control processing]
Now, the engine control apparatus 100 having the above-described configuration performs the engine control process shown below to correct the fuel injection amount at a high altitude without using a pressure sensor such as an atmospheric pressure sensor or an intake pressure sensor. While reducing the necessary data volume, it achieves good startability and suppresses fuel injection with an unnecessary fuel amount. Hereinafter, the operation of the engine control apparatus 100 when executing the engine control process will be described in detail with reference to the flowcharts shown in FIGS.

  FIG. 2A is a flowchart showing the overall flow of the engine control process in the present embodiment.

  The engine control process shown in FIG. 2 (a) starts when the ignition switch of a moving body such as a vehicle is switched from the off state to the on state, and the engine control process proceeds to step S1. The engine control process is repeatedly started and executed every rotation of the engine 1. The engine control process is realized by the engine control device 100 reading and executing a control program stored in the ROM 105a of the memory 105.

  In the process of step S1, the engine speed calculation unit 106 is based on the detected value indicating the rotation angle of the crank 6 output from the crank angle signal detection unit 101 to which the voltage signal from the crank angle sensor 7 is input. , And an electric signal indicating the calculated engine speed NE is output to the fuel injection amount control unit 108 and the ignition timing control unit 109, respectively. Thereby, the process of step S1 is completed and an engine control process progresses to the process of step S2.

  In the process of step S2, the throttle valve opening detector 102 detects the opening TH of the throttle valve 14 based on the voltage signal output from the throttle opening sensor 15, and the detected opening TH of the throttle valve 14 is detected. Is output to the fuel injection amount control unit 108. Thereby, the process of step S2 is completed, and the engine control process proceeds to the process of step S3.

  In the process of step S3, the engine temperature detection unit 104 detects the temperature TW of the engine 1 based on the voltage signal output from the water temperature sensor 3, and outputs an electric signal indicating the detected temperature TW of the engine 1 as the fuel injection amount. Output to the control unit 108. Thereby, the process of step S3 is completed and an engine control process progresses to the process of step S4.

In the process of step S4, the fuel injection amount control unit 108 determines whether or not the engine speed NE calculated by the process of step S1 is equal to or higher than a predetermined reference speed (complete explosion reference value). Here, the reference rotational speed is preset and stored in the ROM 105a as a value larger by a predetermined amount than the rotational speed at the start of the engine 1, and the fuel injection amount control unit 108 stores the value stored in the ROM 105a. Was used. As a result of the determination, if the engine speed NE is less than the predetermined reference speed, the fuel injection amount control unit 108 determines that the engine 1 is not completely detonated, and the engine control process proceeds to step S5. Proceed to processing. On the other hand, as a result of the determination, if the engine speed NE is equal to or higher than the predetermined reference speed, the fuel injection amount control unit 108 determines that the engine 1 is completely exploded, and the engine control process The process proceeds to S6.

  In the process of step S5, the fuel injection amount control unit 108 performs a start-time fuel injection amount calculation process for calculating the fuel injection amount during the engine start, specifically, the period from when the engine 1 is started to the complete explosion. Run. The details of the starting fuel injection amount calculation process will be described later with reference to the flowchart shown in FIG. Thereby, the process of step S5 is completed and a series of engine control processes are complete | finished.

  On the other hand, in the process of step S6, the oxygen sensor output detection unit 103 receives the voltage signal output from the oxygen sensor 19, and then detects the oxygen sensor output voltage VG. Thereby, the process of step S6 is completed, and the engine control process proceeds to the process of step S7.

  In the process of step S7, the oxygen sensor output detection unit 103 changes according to the oxygen concentration in the exhaust gas of the engine 1 based on the value of the oxygen sensor output voltage VG detected by the process of step S6. It is determined whether or not the oxygen sensor 19 is activated by determining whether or not the output voltage VG is detected. If the oxygen sensor output voltage VG is not detected as a result of the determination, the oxygen sensor output detection unit 103 determines that the oxygen sensor 19 is not activated, and the engine control process proceeds to step S9. move on. On the other hand, when the oxygen sensor output voltage VG is detected as a result of the determination, the oxygen sensor output detection unit 103 determines that the oxygen sensor 19 is activated, and the engine control process proceeds to step S8. Proceed to processing.

  In the process of step S8, the oxygen sensor output detection unit 103 decreases the oxygen sensor feedback correction coefficient MG, for example, if the oxygen sensor output voltage VG is equal to or higher than a predetermined value (for example, 0.45 volts or higher), and the oxygen sensor output voltage VG. Is less than a predetermined value (for example, less than 0.45 volts), the oxygen sensor feedback correction coefficient MG is increased so that the air-fuel ratio of the engine 1 becomes the stoichiometric air-fuel ratio corresponding to the oxygen concentration in the exhaust gas of the engine 1. The oxygen sensor feedback correction coefficient MG is calculated as described above, and an electric signal indicating the calculated oxygen sensor feedback correction coefficient MG is output to the air density correction coefficient calculation unit 107. Thereby, the process of step S8 is completed, and the engine control process proceeds to the process of step S9.

  In the process of step S9, the complete explosion in which the air density correction coefficient calculation unit 107 calculates an after-explosion air density correction coefficient MA (second air density correction coefficient), which is an air density correction coefficient after the complete explosion of the engine 1. A post-air density correction coefficient calculation process is executed. Details of the post-combustion air density correction coefficient calculation process will be described later with reference to the flowchart shown in FIG. Thereby, the process of step S9 is completed, and the engine control process proceeds to the process of step S10.

In the process of step S10, the post-combustion injection amount calculation unit 108c reads out map data of the basic fuel injection amount corresponding to the engine speed NE and the throttle opening TH from the ROM 105a, and from the map data, the steps S1 and A basic fuel injection amount corresponding to the engine speed NE and the throttle opening TH obtained by the process of step S2 is calculated. Next, the post-combustion injection amount calculation unit 108c multiplies the basic fuel injection amount calculated in this way by the post-completion air density correction coefficient MA calculated by the air density correction coefficient calculation unit 107 in the process of step S9. Thus, the fuel injection amount T after the complete explosion, which is the fuel injection amount after the complete explosion of the engine 1
I is calculated. Then, the fuel injection amount control unit 108 controls the fuel injection amount of the injector 13 according to the post-complete fuel injection amount TI calculated by the post-combustion injection amount calculation unit 108c, and completes the fuel to be ejected from the injector 13. Post fuel injection is performed. Thereby, the process of step S10 is completed and a series of engine control processes are complete | finished. The engine control parameter of the map data of the basic fuel injection amount includes that the engine speed NE and the throttle opening TH can realize simple and reliable control, but are not limited to these. If necessary, other engine control parameters may be appropriately selected and adopted.

[Starting fuel injection amount calculation processing]
Next, with reference to the flowchart shown in FIG. 2B, the operation of the engine control apparatus 100 when executing the start time fuel injection amount calculation process in the engine control process will be described in detail.

  FIG. 2B is a flowchart showing the flow of the starting fuel injection amount calculation process in the engine control process shown in FIG.

  The starting fuel injection amount calculation process shown in FIG. 2 (b) is started at the timing when it is determined in step S4 shown in FIG. 2 (a) that the engine 1 is not completely exploded. The calculation process proceeds to step S21.

  In the process of step S21, the fuel injection amount control unit 108 reads the value of the initial value calculated flag stored in the RAM 105b and the like, and determines whether or not the value is 1, thereby starting fuel injection at start-up. It is determined whether or not the initial value TISI of the quantity has been calculated. As a result of the determination, when the value of the initial value calculated flag is 1, the fuel injection amount control unit 108 determines that the initial value TISI of the starting fuel injection amount has been calculated, and the starting fuel injection amount. The calculation process proceeds to step S24. On the other hand, as a result of the determination, when the value of the initial value calculated flag is 0, the fuel injection amount control unit 108 determines that the initial value TISI of the start time fuel injection amount has not been calculated, and starts start fuel injection. The amount calculation process proceeds to step S22.

  In the process of step S22, the initial injection amount calculation unit 108a reads the map data of the basic fuel injection amount corresponding to the engine temperature TW from the ROM 105a, and uses the map data to obtain the engine temperature TW obtained by the process of step S3. The corresponding basic fuel injection amount is calculated, and the altitude corrected air density correction coefficient MAS (first air density correction correction coefficient) value is read from the ROM 105a, and the high altitude correction is performed on the calculated basic fuel injection amount. The initial value TISI of the starting fuel injection amount is calculated by multiplying the value of the air density correction coefficient MAS. The initial injection amount calculation unit 108a stores the calculated initial value TISI of the starting fuel injection amount in the RAM 105b or the like. With this process, the initial fuel injection amount when the engine 1 is started is simply set to a fuel injection amount that is smaller than the basic fuel injection amount according to the engine temperature TW. Note that the engine control parameter of the map data of the basic fuel injection amount includes that the engine temperature TW can realize simple and reliable control, but is not limited to these, and may be changed according to need. The engine control parameters may be selected and adopted as appropriate.

Here, the reason why the basic fuel injection amount is multiplied by the air density correction coefficient MAS corrected for the high altitude is that the engine 1 is started in consideration of the case where the engine 1 is started with a moving body such as a vehicle positioned at the high altitude. The initial fuel injection amount at the time of starting the engine, which is suitable for causing the engine 1 to completely explode when a moving body such as a vehicle is located in a low ground and the engine 1 is started, That is, by setting a value smaller than the basic fuel injection amount corresponding to the engine temperature TW, it is possible to reliably obtain an optimal fuel injection amount for complete explosion when the engine 1 is actually started at high altitude. In other words, if the initial fuel injection amount at the time of starting the engine in the high altitude is set excessively, the engine 1 easily completes explosion, but the air-fuel mixture continues to be kept in a rich state unnecessarily. Therefore, a configuration is adopted in which such a situation does not occur because a proper fuel injection amount cannot be obtained. Thereby, the process of step S22 is completed, and the start time fuel injection amount calculation process proceeds to the process of step S23. Here, specifically, as the air density correction coefficient MAS corrected for the high altitude, it is necessary to completely explode the engine 1 when the engine 1 is started at an altitude of 2000 m assuming that the altitude is about 2000 m. A value capable of giving initial fuel injection at the time of starting the engine is employed, and in such a case, the value is set to 0.8, for example.

  In the process of step S23, the fuel injection amount control unit 108 sets the value of the initial value calculated flag indicating that the initial value TISI of the starting fuel injection amount has been calculated to 1 and stores it in the RAM 105b or the like. Thereby, the process of step S23 is completed, and the start time fuel injection amount calculation process proceeds to the process of step S28.

  On the other hand, in the process of step S24, the fuel injection amount control unit 108 reads the value of the air density correction coefficient MAS corrected for the high altitude from the ROM 105a, or has been stored in the RAM 105b or the like in the previous process of step S26. The value of the air density correction coefficient MAS is read out, and it is determined whether or not the read value is equal to or greater than a predetermined value. As a result of the determination, if the read value is equal to or greater than the predetermined value, the start time fuel injection amount calculation process proceeds to step S25. On the other hand, as a result of the determination, if the read value is less than the predetermined value, the start time fuel injection amount calculation process proceeds to step S26. Here, the determined predetermined value is an air density correction coefficient MAS in which the air-fuel mixture does not unnecessarily become rich because the fuel injection amount at the start is unnecessarily increased in the process from the start of the engine 1 to the complete explosion. Is set to 1, which is the value of.

  In the process of step S25, the fuel injection amount control unit 108 sets the value of the air density correction coefficient MAS corrected for high altitude to 1, and the value of the set air density correction coefficient MAS corrected for high altitude is stored in the RAM 105b or the like. Remember. By setting the value of the air density correction coefficient MAS to 1 in this processing, it is possible to suppress the air-fuel mixture from becoming unnecessarily rich in the process from the start of the engine 1 to the complete explosion. Thereby, the process of step S25 is completed, and the start time fuel injection amount calculation process proceeds to the process of step S27.

  In the process of step S26, the fuel increase control unit 108b reads the value of the air density correction coefficient MAS corrected for the high altitude from the ROM 105a, or the increased air density correction stored in the RAM 105b or the like in the previous process of step S26. The value of the coefficient MAS is read, and a predetermined value smaller than 1 is added to the value to increase the value of the air density correction coefficient MAS corrected for high altitude, and the increased value of the air density correction coefficient MAS is stored in the RAM 105b. And so on. With this process, the air density correction coefficient MAS corrected for the high altitude is successively increased and updated by a predetermined value for each rotation of the engine 1. Thereby, the process of step S26 is completed, and the start time fuel injection amount calculation process proceeds to the process of step S27. Here, the predetermined value smaller than 1 used for the addition is determined in consideration of how many times it should be increased depending on the time from when the engine 1 is started until the complete explosion is reached. The value may be set to a sufficiently small value of 0.03.

In the process of step S27, the initial injection amount calculating unit 108a reads the increased air density correction coefficient MAS value stored in the RAM 105b or the like in the process of step S25 or the process of step S26, and the RAM 105b in the process of step S22. The initial fuel injection amount TIS, which is sequentially increased from the initial fuel injection amount TISI, is calculated by reading the initial fuel injection amount initial value TISI stored in The calculated starting fuel injection amount TIS is stored in the RAM 105b or the like. By this process, the starting fuel injection amount TIS is sequentially increased and updated every rotation of the engine 1 in accordance with the air density correction coefficient MAS that is sequentially increased in the process of step S26. Thereby, the process of step S27 is completed, and the start time fuel injection amount calculation process proceeds to the process of step S28.

  In the process of step S28, the fuel injection amount control unit 108 reads the initial fuel injection amount initial value TISI stored in the RAM 105b or the like in the process of step S22, or is stored in the RAM 105b or the like in the process of step S27. The value of the starting fuel injection amount TIS is read, the fuel injection amount of the injector 13 is controlled according to the value, and the starting fuel injection for injecting fuel from the injector 13 is performed. Thereby, the process of step S28 is completed, a series of start time fuel injection amount calculation processes are completed, and a series of engine control processes shown in FIG.

[Air density correction coefficient calculation after complete explosion]
Next, with reference to the flowchart shown in FIG. 3, the operation of the engine control apparatus 100 when executing the post-combustion air density correction coefficient calculation process in the engine control process shown in FIG. 2A will be described in detail. .

  FIG. 3 is a flowchart showing a flow of post-combustion air density correction coefficient calculation processing in the engine control processing shown in FIG.

  The flowchart shown in FIG. 3 starts at the timing when it is determined that the oxygen sensor 19 is not activated in the process of step S7 shown in FIG. 2A or when the process of step S8 shown in FIG. 2A is completed. Thus, the post-explosion air density correction coefficient calculation process proceeds to the process of step S31.

  In the process of step S31, the fuel injection amount control unit 108 reads the value of the after-explosion post-explosion air density correction coefficient calculated flag stored in the RAM 105b or the like, and determines whether the value is 1 or not. Then, it is determined whether or not a post-explosion air density correction coefficient MA (second air density correction coefficient) that is an air density correction coefficient after the complete explosion of the engine 1 has been calculated. As a result of the determination, if the value of the post-explosion air density correction coefficient calculated flag is 1, the fuel injection amount control unit 108 determines that the post-explosion air density correction coefficient MA has been calculated, and the completion is completed. The post-explosion air density correction coefficient calculation process proceeds to step S34. On the other hand, as a result of the determination, when the value of the after-explosion air density correction coefficient calculated flag is 0, the fuel injection amount control unit 108 determines that the after-explosion air density correction coefficient MA has not been calculated, The post-combustion air density correction coefficient calculation process proceeds to step S32.

  In the process of step S32, the air density correction coefficient calculation unit 107 reads the value of the increased air density correction coefficient MAS stored in the RAM 105b or the like in the process of step S26 shown in FIG. After the complete explosion, the air density correction coefficient MA is set, and the set value is stored in the RAM 105b or the like. Thereby, the process of step S32 is completed and the post-explosion air density correction coefficient calculation process proceeds to the process of step S33.

  In the process of step S33, the fuel injection amount control unit 108 sets the post-explosion post-explosion air density correction coefficient calculated flag value to 1, and stores the value in the RAM 105b or the like. Thereby, the process of step S33 is completed, and the post-explosion air density correction coefficient calculation process proceeds to the process of step S38.

On the other hand, in the process of step S34, the oxygen sensor output detection unit 103 calculates a moving average value between the maximum and minimum peak values of the oxygen sensor feedback correction coefficient MG, and the fluctuation amount of the moving average value is within a predetermined range. It is determined whether or not the oxygen sensor feedback correction coefficient MG has converged. If the variation amount of the oxygen sensor feedback correction coefficient MG is not within the predetermined range as a result of the determination, the oxygen sensor output detection unit 103 determines that the oxygen sensor feedback correction coefficient MG has not converged, and a series of complete explosions The rear air density correction coefficient calculation process ends, and a series of engine control processes shown in FIG. On the other hand, if the variation amount of the oxygen sensor feedback correction coefficient MG is within the predetermined range as a result of the determination, the oxygen sensor output detection unit 103 determines that the oxygen sensor feedback correction coefficient MG has converged, and the air after complete explosion The density correction coefficient calculation process proceeds to step S35. The predetermined range, that is, the upper limit value and the lower limit value thereof are appropriately set in consideration of the type of the oxygen sensor 19 and the resolution of the oxygen sensor output detection unit 103 and stored in advance in the ROM 105a. Used by reading from the ROM 105a.

  In the process of step S35, the oxygen sensor output detection unit 103 sets the converged oxygen sensor feedback correction coefficient MG as the converged oxygen sensor feedback correction coefficient MGR, the converged oxygen sensor feedback correction coefficient MGR, and the post-explosion air density. When the value of the correction coefficient MA is appropriate, a deviation is calculated from 1.0 times that is the value that the post-convergence oxygen sensor feedback correction coefficient MGR should take, and is the calculated deviation value equal to or greater than a predetermined value? Determine whether or not. As a result of the determination, if the deviation value is less than the predetermined value, the series of post-combustion air density correction coefficient calculation processing ends, and the series of engine control processing shown in FIG. . On the other hand, as a result of the determination, if the deviation value is equal to or greater than the predetermined value, the oxygen sensor output detection unit 103 sends an electric signal indicating the value of the post-convergence oxygen sensor feedback correction coefficient MGR to the air density correction coefficient calculation unit 107. Then, the post-explosion post-explosion air density correction coefficient calculation process proceeds to the process of step S36. Here, the predetermined value for comparing the deviation values is that the value of the post-explosion air density correction coefficient MA set in the process of step S32 or the process of step S36 increases the fuel injection amount unnecessarily, and the air-fuel mixture. What is necessary is just to set as a necessary and sufficient value in order to correct the state used as the value which makes it unnecessarily rich, and is set to 0.07 here.

  In the process of step S36, the air density correction coefficient calculation unit 107 reads the value of the post-explosion air density correction coefficient MA stored in the RAM 105b or the like in the process of step S32 or the previous process of step S36, and sets the value. A value obtained by multiplying the value of the post-convergence oxygen sensor feedback correction coefficient MGR output in the process of step S35 is set as the value of the post-explosion air density correction coefficient MA, and an electric signal indicating the set value is set as the fuel injection amount control unit. 108, more specifically, the set value is output to the post-combustion injection amount calculation unit 108c and stored in the RAM 105b or the like. By this processing, the value of the air density correction coefficient MA after the complete explosion is a value that does not unnecessarily increase the fuel injection amount and unnecessarily make the air-fuel mixture rich. In other words, the current vehicle or the like moves It is corrected and updated to a value suitable for the altitude at which the body is located. Thereby, the process of step S36 is completed, and the post-explosion air density correction coefficient calculation process proceeds to the process of step S37.

  In the process of step S37, the oxygen sensor output detection unit 103 resets the values of the oxygen sensor feedback correction coefficient MG and the post-convergence oxygen sensor feedback correction coefficient MGR held by itself to 1 for the next process. Thereby, the process of step S37 is completed, and the post-explosion air density correction coefficient calculation process proceeds to the process of step S38.

  In the process of step S38, the air density correction coefficient calculating unit 107 calculates the value of the atmospheric pressure PA based on the value of the post-explosion air density correction coefficient MA obtained in the process of step S36, and the calculated value is stored in the RAM 105b or the like. To remember. The value of the atmospheric pressure PA stored in the memory 105 is used for display on a display device provided in a moving body such as a vehicle and various controls. Thereby, the process of step S38 is completed, and a series of post-combustion air density correction coefficient calculation processes ends.

〔Concrete example〕
Finally, a specific example of the above engine control process will be described in detail with reference to FIG.

  FIG. 4 is a timing chart for explaining a specific example of the engine control process in the present embodiment. FIG. 4A is a timing chart of air density correction coefficients MAS and MA and oxygen sensor feedback correction coefficients MG and MGR. FIG. 4B shows a timing chart of the engine speed NE and the fuel injection amounts TIS, TI. In this specific example, for convenience of explanation, it is assumed that the opening degree of the throttle valve 14 after the engine is started is constant.

(1) Time T = T0
At time T = T0 shown in FIG. 4, when the ignition switch is switched from the off state to the on state and the engine is started, the engine control process is repeatedly started for each rotation of the engine 1. As described above, at the timing when the engine control process is started, the initial injection amount calculation unit 108a has the basic fuel injection amount corresponding to the engine temperature TW corrected to the high altitude corresponding to the altitude equivalent to 2000m above sea level. The initial value TISI of the starting fuel injection amount is calculated by multiplying by MAS (the value in this specific example is 0.8). Then, the fuel injection amount control unit 108 controls the fuel injection amount of the injector 13 according to the initial value TISI of the starting fuel injection amount calculated by the initial injection amount calculation unit 108a, and starts to inject fuel from the injector 13.

(2) Period T = T0 to T1
Next, in the period T = T0 to T1, the fuel increase control unit 108b sequentially increases the value of the air density correction coefficient MAS corrected for the high altitude for each rotation of the engine 1, and the initial injection amount calculation unit 108a By multiplying the increased air density correction coefficient MAS by the initial value TISI of the starting fuel injection amount, the starting fuel injection amount TIS is sequentially increased and calculated. Then, the fuel injection amount control unit 108 controls the fuel injection amount of the injector 13 in accordance with the starting fuel injection amount TIS calculated by the initial injection amount calculation unit 108a, and ejects fuel from the injector 13.

(3) Period T = T1-T2
Next, when it is determined that the engine 1 has completely exploded at time T = T1, the air density correction coefficient calculation unit 107 determines the time of the increased air density correction coefficient MAS that has been sequentially increased up to time T = T1. The value at the time T = T1 (0.87 in this specific example) is set as the value of the after-explosion air density correction coefficient MA, and the after-explosion injection amount calculation unit 108c sets the engine speed NE, the throttle opening TH, The post-combustion fuel injection amount TI is calculated by multiplying the basic fuel injection amount corresponding to 1 by the post-explosion air density correction coefficient MA. Then, the fuel injection amount control unit 108 controls the fuel injection amount of the injector 13 according to the post-complete-explosion fuel injection amount TI calculated by the post-complete-explosion injection amount calculation unit 108c, and ejects fuel from the injector 13. The control of the fuel injection amount itself is maintained until time T = T3 after time T = T2.

(4) Period T = T2-T3
Next, when a voltage signal corresponding to the rotation of the engine 1 starts to be output from the oxygen sensor 19 at time T = T2, the oxygen sensor output detection unit 103 activates the oxygen sensor 19 until time T = T3. Is calculated, a moving average value between the maximum and minimum peak values of the oxygen sensor feedback correction coefficient MG is calculated, and by determining whether or not the fluctuation amount of the moving average value is within a predetermined range, It is determined whether or not the oxygen sensor feedback correction coefficient MG has converged, and after the oxygen sensor feedback correction coefficient MG has converged, a deviation Δx between the post-convergence oxygen sensor feedback correction coefficient MGR and a predetermined value 10 times is calculated. Deviation Δx
Is determined to be greater than or equal to a predetermined value of 0.07.

(5) After time T = T3 Next, when it is determined at time T = T3 whether the deviation Δx is equal to or greater than the predetermined value 0.07, the air density correction coefficient calculation unit 107 performs the current post-explosion post-explosion air density correction. A value obtained by multiplying the value of the coefficient MA by the value of the post-convergence oxygen sensor feedback correction coefficient MGR is set and updated as the value of the air density correction coefficient MA after the complete explosion, and the post-combustion injection amount calculation unit 108c performs basic fuel injection. The post-explosion fuel injection amount TI is calculated by multiplying the amount by the post-explosion post-explosion air density correction coefficient MA. At this time, the value of the post-explosion air density correction coefficient MA is corrected to a value suitable for the altitude at which the moving body such as a vehicle is currently located. Specifically, in the period T = T2 to T3, the value of the after-explosion air density correction coefficient MA is 0.87, and the value of the post-convergence oxygen sensor feedback correction coefficient MGR is 0.92. Multiplied by approximately 0.8, it can be seen that the moving object such as a vehicle is currently located at a high altitude equivalent to an altitude of 2000 m, and the value of the air density correction coefficient MA after the complete explosion is an altitude equivalent to an altitude of 2000 m It can be seen that it has been corrected to a value suitable for. Then, after time T = T3, the fuel injection amount control unit 108 controls the fuel injection amount of the injector 13 according to the post-combustion fuel injection amount TI calculated by the post-combustion injection amount calculation unit 108c. Blow out the fuel. At this time, the engine speed NE is stabilized at a predetermined idle speed.

  As is apparent from the above description, in the engine control process in the present embodiment, the initial injection amount calculation unit 108a takes into account the high-altitude corrected air density correction coefficient MAS, and the initial fuel injection amount at the start of the engine 1 The value TISI is calculated as a fuel injection amount that is smaller than the basic fuel injection amount according to the engine temperature TW, and the fuel increase control unit 108b sequentially increases the air density correction coefficient MAS so that the fuel injection amount at the start of the engine 1 is increased. The TIS is sequentially increased from the initial value TISI of the starting fuel injection amount, and the post-combustion injection amount calculation unit 108c sets the air density correction coefficient MAS sequentially increased by the fuel increase control unit 108b after the complete explosion of the engine 1. In view of this, since the fuel injection amount TI after the complete explosion of the engine 1 is calculated, the fuel is not used without using a pressure sensor such as an atmospheric pressure sensor or an intake pressure sensor. While reducing the data capacity required in the highlands correction amount morphism, it is possible to achieve good startability, it is possible to suppress the fuel injection in unnecessary fuel amount.

  Further, in the engine control process according to the present embodiment, the air density correction coefficient calculation unit 107 takes into account the air density correction coefficient MAS sequentially increased by the fuel increase control unit 108b after the engine 1 has completed the complete explosion. The post-combustion post-combustion injection amount calculation unit 108c calculates the post-explosion post-explosion injection amount calculation unit 108c in consideration of the post-completion post-explosion air density correction coefficient MA, and calculates the post-combustion fuel injection amount TI. Thus, it is possible to realize a reliable startability and to more reliably suppress fuel injection with an unnecessary fuel amount after the complete explosion of the engine 1.

  Further, in the engine control process in the present embodiment, the air density correction coefficient calculation unit 107 activates the oxygen sensor 19 attached to the exhaust system of the engine 1, and oxygen sensor feedback according to the output value from the oxygen sensor 19. Until the correction coefficient MG converges, the air density correction coefficient MAS, which is sequentially increased by the fuel increase control unit 108b, is set as the air density correction coefficient MA after the complete explosion, so that good startability can be realized and the oxygen sensor 19 According to the operation state, fuel injection with an unnecessary fuel amount after the complete explosion of the engine 1 can be suppressed.

Further, in the engine control process in the present embodiment, after the oxygen sensor 19 is activated and the oxygen sensor feedback correction coefficient MG converges, the air density correction coefficient calculation unit 107 detects the deviation of the post-convergence oxygen sensor feedback correction coefficient MGR. When the value exceeds the predetermined value, the post-convergence oxygen sensor feedback correction coefficient MGR is further taken into consideration to calculate the post-explosion air density correction coefficient MA, so that good startability can be realized and the operation of the oxygen sensor 19 is performed. According to the state, fuel injection with an unnecessary fuel amount after the complete explosion of the engine 1 can be more reliably suppressed.

  In the present invention, the type, arrangement, number, and the like of the members are not limited to the above-described embodiments, and the components depart from the gist of the invention, such as appropriately replacing the constituent elements with those having the same operational effects. Of course, it can be appropriately changed within the range not to be.

  As described above, in the present invention, good startability can be realized while reducing the data volume necessary for high altitude correction of the fuel injection amount without using a pressure sensor such as an atmospheric pressure sensor or an intake pressure sensor. An engine control device capable of suppressing fuel injection at an unnecessary fuel amount can be provided, and can be widely applied to an engine of a moving body such as a vehicle because of its universality. Expected.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Cylinder block 3 ... Water temperature sensor 4 ... Piston 5 ... Connecting rod 6 ... Crank 7 ... Crank angle sensor 8 ... Cylinder head 9 ... Combustion chamber 10 ... Spark plug 11 ... Intake passage 12 ... Intake valve 13 ... Injector 14 ... Throttle valve 15 ... Throttle opening sensor 16 ... Exhaust passage 17 ... Exhaust valve 18 ... Catalyst converter 19 ... Oxygen sensor 100 ... Engine control device 101 ... Crank angle signal detector 102 ... Throttle valve opening detector 103 ... Oxygen sensor output detection Unit 104 ... Engine temperature detection unit 105 ... Memory 105a ... ROM
105b ... RAM
105c… EEPROM
106 ... engine speed calculation unit 107 ... air density correction coefficient calculation unit 108 ... fuel injection amount control unit 108a ... initial injection amount calculation unit 108b ... fuel increase control unit 108c ... post-explosion injection amount calculation unit 109 ... ignition timing control unit

Claims (4)

The initial fuel injection amount at engine startup is calculated as an initial fuel injection amount that is smaller than the basic fuel injection amount according to the engine temperature, taking into account the predetermined first air density correction coefficient corrected for high altitude. An initial injection amount calculation unit;
A fuel increase control unit that sequentially increases the initial fuel injection amount by sequentially increasing the first air density correction coefficient;
In consideration of the air density correction coefficient sequentially increased by the fuel increase control unit after the complete explosion of the engine corresponding to the engine rotation speed exceeding the complete explosion reference value after starting the engine, A post-combustion injection amount calculation unit for calculating a fuel injection amount after the complete explosion of the engine;
An engine control device comprising: An air density correction coefficient calculating unit that calculates a second air density correction coefficient in consideration of the air density correction coefficient sequentially increased by the fuel increase control unit after the complete explosion of the engine;
2. The engine control device according to claim 1, wherein the post-combustion injection amount calculation unit calculates a fuel injection amount after the complete explosion of the engine in consideration of the second air density correction coefficient. .   The air density correction coefficient calculation unit controls the fuel increase until the oxygen sensor attached to the exhaust system of the engine is activated and the oxygen sensor feedback correction coefficient corresponding to the output value from the oxygen sensor converges. The engine control device according to claim 2, wherein an air density correction coefficient that is sequentially increased by the unit is set as the second air density correction coefficient.   When the deviation of the oxygen sensor feedback correction coefficient becomes equal to or larger than a predetermined value after the oxygen sensor is activated and the oxygen sensor feedback correction coefficient converges, the air density correction coefficient calculation unit further includes the oxygen sensor. The engine control apparatus according to claim 3, wherein the second air density correction coefficient is calculated in consideration of a feedback correction coefficient.

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