JP6773545B2 - Internal combustion engine control device - Google Patents

Description

The present invention relates to a control device for an internal combustion engine.

In Patent Document 1, the combustion pressure in the combustion chamber is detected, the maximum value of the detected change rate of the combustion pressure is calculated, and the calculated maximum value is the target maximum combustion pressure set according to the operating state of the internal combustion engine. A fuel injection control device for an internal combustion engine that feedback-controls the fuel injection timing so as to match the rate of change is disclosed. Further, Patent Document 1 discloses that when the engine is idling, the basic injection timing map is searched and the basic injection timing is calculated according to the engine speed and the required torque of the engine.

Japanese Unexamined Patent Publication No. 2006-9600

By the way, some control devices for an internal combustion engine perform feedback control so that the internal combustion engine main body is in a desired combustion state based on the in-cylinder pressure of the internal combustion engine main body. A control device for an internal combustion engine that performs such feedback control may not be able to appropriately perform feedback control if the pressure rise in the cylinder pressure of the internal combustion engine body is small. For example, if the pressure rise in the internal combustion engine body pressure is small, the accuracy of the combustion state of the internal combustion engine body calculated from the internal combustion engine body becomes poor (for example, the S / N ratio becomes small), and the control device of the internal combustion engine becomes It may not be possible to properly perform feedback control based on the in-cylinder pressure.

Therefore, the internal combustion engine has a problem that if the feedback control of the combustion state based on the in-cylinder pressure is not properly performed, an engine stall or the like occurs and the internal combustion engine is not in an appropriate operating state.

It should be noted that Patent Document 1 describes that the basic injection timing map is searched and the basic injection timing is calculated in the idling operation state, but when the pressure rise in the cylinder pressure other than the idling operation state is small. There is no description about control. Therefore, the internal combustion engine of Patent Document 1 may cause an engine stall or the like in a state other than the idling operation state.

An object of the present invention is to provide a control device for an internal combustion engine that controls the internal combustion engine so as to be in an appropriate operating state.

In the internal combustion engine control device of the present invention, when the internal combustion engine main body is in a non-idle state and the pressure rise in the cylinder pressure is in the first state of a predetermined value or less, the rotation speed and the accelerator opening degree of the internal combustion engine main body are Based on the above, the combustion feed forward control unit that performs feed forward control so that the internal combustion engine main body is in a desired combustion state, and the internal combustion engine main body are in a non-idle state, and the pressure increase in the cylinder pressure is determined. It has a combustion feedback control unit that performs feedback control so that the internal combustion engine main body becomes a desired combustion state based on the in-cylinder pressure when it is in a second state larger than the value.

According to the present invention, the internal combustion engine can be controlled to be in an appropriate operating state.

It is a schematic block diagram of the internal combustion engine which concerns on embodiment of this invention. It is a figure which showed the block composition example of the combustion F / F control part. It is a figure explaining the operation example of the combustion F / B control unit. It is a figure explaining the relationship between the idle state, the idle vicinity state, and the combustion F / B enable state of the internal combustion engine main body, and the control of an ECU. It is a figure explaining the switching operation of a switching part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an internal combustion engine according to an embodiment of the present invention. As shown in FIG. 1, the internal combustion engine 1 includes an air cleaner 11, a turbocharger 12, an intercooler 13, an internal combustion engine main body 14, a fuel injection device 15, a crank angle sensor 21, an in-cylinder pressure sensor 22, and the like. It has an accelerator sensor 23, an intake passage 31, an exhaust passage 32, and an ECU (Engine Control Unit) 40. The internal combustion engine 1 has an intake throttle, an EGR (Exhaust Gas Recirculation), and the like, but is not shown in FIG.

The turbocharger 12 has a turbine 12a that rotates by the force of exhaust gas flowing in the exhaust passage 32, and a compressor 12b that rotates together with the turbine 12a and sends air in the intake passage 31 to the internal combustion engine main body 14. The air introduced from the air cleaner 11 into the intake passage 31 is pressurized by the compressor 12b and sent to the combustion chamber of the internal combustion engine main body 14 via the intercooler 13.

The fuel injection device 15 injects fuel into the internal combustion engine main body 14 in response to an instruction from the ECU 40. The fuel injection device 15 is, for example, an injector.

The crank angle sensor 21 is provided on the internal combustion engine main body 14 and detects the rotation speed of the internal combustion engine main body 14. The crank angle sensor 21 outputs the detected rotation speed of the internal combustion engine main body 14 to the ECU 40.

The in-cylinder pressure sensor 22 is provided in the internal combustion engine main body 14 and detects the in-cylinder pressure of the internal combustion engine main body 14. The in-cylinder pressure sensor 22 outputs the detected in-cylinder pressure of the internal combustion engine main body 14 to the ECU 40.

The accelerator sensor 23 is provided on the accelerator and detects the accelerator opening degree of the accelerator. The accelerator sensor 23 outputs the detected accelerator opening degree to the ECU 40.

The ECU 40 controls the entire internal combustion engine 1 and also controls the operating state of the internal combustion engine main body 14. As shown in FIG. 1, the ECU 40 includes a rotation F / B (F / B: feedback) control unit 41, a combustion F / F (F / F: feedback) control unit 42, and a combustion F / B control unit 43. , A switching unit 44, and a storage unit 45.

The functions of the rotation F / B control unit 41, the combustion F / F control unit 42, the combustion F / B control unit 43, and the switching unit 44 of the ECU 40 are realized by, for example, a CPU (Central Processing Unit). The function of the storage unit 45 is realized by, for example, a memory. A program executed by the CPU and various data are stored in the storage unit 45.

The rotation F / B control unit 41 controls the F / B so that the internal combustion engine main body 14 becomes the idle speed based on the rotation speed detected by the crank angle sensor 21 when the internal combustion engine main body 14 is in the idle state. I do. For example, the rotation F / B control unit 41 controls the idle rotation speed of the internal combustion engine main body 14 by manipulating the injection amount and injection timing of the fuel injection device 15. The idle state is a no-load state of the internal combustion engine main body 14, for example, a state in which the accelerator opening degree is “0” and the internal combustion engine main body 14 is at a preset idle speed.

The combustion F / F control unit 42 uses the crank angle sensor 21 when the internal combustion engine main body 14 is in the non-idle state and the pressure rise (width value of the pressure rise) in the cylinder of the internal combustion engine main body 14 is equal to or less than a predetermined value. Based on the detected rotation speed and the accelerator opening degree detected by the accelerator sensor 23, the F / F control is performed so that the internal combustion engine main body 14 is in a desired combustion state. For example, the combustion F / F control unit 42 controls the internal combustion engine main body 14 to be in a desired combustion state by manipulating the injection amount and injection timing of the fuel injection device 15.

The predetermined value is equal to or greater than the minimum value of the pressure increase in the in-cylinder pressure, which allows the combustion F / B control unit 43, which will be described later, to appropriately perform F / B control based on the in-cylinder pressure of the internal combustion engine main body 14. The value. The predetermined value is stored in the storage unit 45 in advance, for example. Further, the combustion state of the internal combustion engine main body 14 means, for example, the state of the combustion center of gravity and the torque of the internal combustion engine main body 14. Hereinafter, a state in which the internal combustion engine main body 14 is in a non-idle state and the pressure rise in the cylinder pressure is equal to or less than a predetermined value may be referred to as a “near idle state”.

FIG. 2 is a diagram showing a block configuration example of the combustion F / F control unit 42. As shown in FIG. 2, the combustion F / F control unit 42 includes a calculation unit 51 and a filter 52.

The calculation unit 51 refers to, for example, a combustion map based on the number of revolutions detected by the crank angle sensor 21 and the accelerator opening degree detected by the accelerator sensor 23, and sets the internal combustion engine main body 14 to a desired combustion state. The fuel injection amount indicated value (for example, the fuel injection timing and the fuel injection amount) is calculated.

The filter 52 passes the low frequency component of the fuel injection amount indicated value calculated by the calculation unit 51. The filter 52 is, for example, a first-order lag filter or a second-order lag low-pass filter. The fuel injection device 15 injects the fuel of the fuel injection amount indicated value output from the filter 52 into the internal combustion engine main body 14.

As described above, the calculation unit 51 refers to the combustion map based on the rotation speed of the internal combustion engine main body 14 and the accelerator opening degree, and the fuel injection amount indicated value for bringing the internal combustion engine main body 14 into a desired combustion state. Is calculated. Therefore, for example, when the accelerator opening degree becomes "0" from a certain value, the fuel injection amount indicated value also becomes "0" from a certain value. For example, when the fuel injection amount indicated value suddenly changes to "0", the internal combustion engine main body 14 may cause an engine stall or the like. Therefore, the filter 52 gently changes and outputs the fuel injection amount indicated value output from the calculation unit 51. As a result, the internal combustion engine main body 14 is suppressed from stalling and the like.

Returning to the description of FIG. The combustion F / B control unit 43 is based on the in-cylinder pressure detected by the in-cylinder pressure sensor 22 when the internal combustion engine main body 14 is in the non-idle state and the pressure increase of the in-cylinder pressure of the internal combustion engine main body 14 is larger than a predetermined value. Then, F / B control is performed so that the internal combustion engine main body 14 is in a desired combustion state. That is, the combustion F / B control unit 43 operates when an appropriate calculation accuracy of the combustion state can be obtained. For example, the combustion F / B control unit 43 controls the internal combustion engine main body 14 to be in a desired combustion state by manipulating the injection amount and injection timing of the fuel injection device 15.

The desired combustion state means, for example, a combustion state according to the accelerator opening degree detected by the accelerator sensor 23. Further, the combustion state (combustion center of gravity and torque) can be calculated from, for example, the in-cylinder pressure detected by the in-cylinder pressure sensor 22 at each crank angle of the internal combustion engine main body 14. Hereinafter, a state in which the internal combustion engine main body 14 is in a non-idle state and the pressure rise in the cylinder pressure is larger than a predetermined value may be referred to as a “combustion F / B enabled state”.

FIG. 3 is a diagram illustrating an operation example of the combustion F / B control unit 43. FIG. 3 shows the internal combustion engine main body 14 and the combustion F / B control unit 43 shown in FIG. 1, and other illustrations are omitted.

As shown in FIG. 3, the combustion F / B control unit 43 calculates the combustion state (combustion center of gravity, torque) of the internal combustion engine main body 14 from the in-cylinder pressure at each crank angle of the internal combustion engine main body 14. Then, the combustion F / B control unit 43 calculates the fuel injection amount and the injection timing of the fuel injected into the internal combustion engine main body 14 so that the calculated combustion state of the internal combustion engine main body 14 becomes a desired combustion state. The crank angle of the internal combustion engine main body 14 can be obtained from the crank angle sensor 21 provided on the internal combustion engine main body 14.

Here, the idle state, the idle vicinity state, and the combustion F / B enable state of the internal combustion engine main body 14, and the rotation F / B control unit 41, the combustion F / F control unit 42, and the combustion F / B control unit 43 The relationship will be explained.

FIG. 4 is a diagram illustrating the relationship between the idle state, the idle vicinity state, and the combustion F / B enabled state of the internal combustion engine main body 14 and the control of the ECU 40. As shown in FIG. 4, the internal combustion engine main body 14 is divided into an idle state and a non-idle state. Further, as shown in FIG. 4, the non-idle state of the internal combustion engine main body 14 is a state near idle in which the pressure rise in the cylinder pressure is equal to or less than a predetermined value, and a combustion F / B enabled state in which the pressure rise in the cylinder pressure is larger than the predetermined value. It is divided into.

As shown in FIG. 4, when the internal combustion engine main body 14 is in the idle state, the rotary F / B control unit 41 operates. That is, when the internal combustion engine main body 14 is in the idle state, the rotation F / B control unit 41 controls the internal combustion engine main body 14 by F / B based on the rotation speed of the internal combustion engine main body 14.

Further, as shown in FIG. 4, when the internal combustion engine main body 14 is in the idle vicinity state, the combustion F / F control unit 42 operates. That is, when the internal combustion engine main body 14 is in the idle vicinity state, the combustion F / F control unit 42 determines the rotation speed of the internal combustion engine main body 14 detected by the crank angle sensor 21 and the accelerator of the accelerator acquired by the accelerator sensor 23. The internal combustion engine main body 14 is F / F controlled based on the opening degree.

Further, as shown in FIG. 4, when the internal combustion engine main body 14 is in the combustion F / B enabled state, the combustion F / B control unit 43 operates. That is, when the internal combustion engine main body 14 is in the combustion F / B enabled state, the combustion F / B control unit 43 presses the internal combustion engine main body 14 based on the in-cylinder pressure of the internal combustion engine main body 14 detected by the in-cylinder pressure sensor 22. F / B control.

Here, when the internal combustion engine main body 14 is in the idle state or is in the vicinity of the idle state, the pressure increase in the cylinder pressure is small. When the pressure rise of the in-cylinder pressure of the internal combustion engine main body 14 is small, the S / N ratio of the combustion state calculated from the in-cylinder pressure becomes small. Therefore, if the F / B control in the combustion state is performed using the in-cylinder pressure when the internal combustion engine main body 14 is in the idle state or the in-cylinder pressure when the internal combustion engine main body 14 is in the vicinity of the idle state, the F / B control is performed appropriately. It may not be broken.

Therefore, when the internal combustion engine main body 14 is in the idle state, the rotary F / B control unit 41 operates as shown in FIG. As a result, the internal combustion engine main body 14 is in an appropriate operating state in the idle state without causing, for example, an engine stall.

Further, when the internal combustion engine main body 14 is in the idle vicinity state, the combustion F / F control unit 42 operates as shown in FIG. As a result, the internal combustion engine main body 14 is in an appropriate operating state without causing, for example, an engine stall even in a state near idle.

Returning to the description of FIG. The switching unit 44 switches the control of the rotation F / B control unit 41, the combustion F / F control unit 42, and the combustion F / B control unit 43. For example, in the switching unit 44, when the accelerator is depressed while the internal combustion engine main body 14 is in the idle state and the calculated value by the combustion F / F control becomes larger than the fuel injection amount by the rotation F / B control, the combustion F The control is switched so that the / F control unit 42 performs F / F control. The combustion F / F control unit 42 calculates the fuel injection amount independently of the rotation F / B control unit 41.

Further, in the switching unit 44, when the internal combustion engine main body 14 is in the idle vicinity state and the pressure rise in the cylinder pressure of the internal combustion engine main body 14 becomes larger than a predetermined value, the combustion F / B control unit 43 controls the F / B. Switch control to do. In other words, in the switching unit 44, when the pressure rise in the cylinder pressure of the internal combustion engine main body 14 becomes larger than a predetermined value while the combustion F / F control unit 42 is operating, the combustion F / B control unit 43 is F / The control is switched so as to perform the B control.

Further, in the switching unit 44, when the internal combustion engine main body 14 is in the idle vicinity state, the rotation speed detected by the crank angle sensor 21 becomes the idle rotation speed, and the fuel injection amount calculated by the rotation F / B control. When exceeds the calculated value by the combustion F / F control, the control is switched so that the rotary F / B control unit 41 performs the F / B control. In other words, in the switching unit 44, the rotation speed detected by the crank angle sensor 21 becomes the idle rotation speed when the combustion F / F control unit 42 is operating, and the rotation speed is calculated by the rotation F / B control. When the fuel injection amount is larger than the value calculated by the combustion F / F control, the control is switched so that the rotary F / B control unit 41 performs the F / B control. The rotary F / B control unit 41 calculates the fuel injection amount independently of the combustion F / F control unit 42.

Further, in the switching unit 44, when the internal combustion engine main body 14 is in the combustion F / B enabled state and the pressure rise of the in-cylinder pressure of the internal combustion engine main body 14 becomes equal to or less than a predetermined value, the combustion F / F control unit 42 F / F / F. The control is switched so as to perform F control. In other words, when the combustion F / B control unit 43 is operating and the pressure rise in the cylinder pressure of the internal combustion engine main body 14 becomes equal to or less than a predetermined value, the switching unit 44 causes the combustion F / F control unit 42 to F / The control is switched so as to perform F control.

FIG. 5 is a diagram illustrating a switching operation of the switching unit 44. As shown by arrow A1 in FIG. 5, when the rotary F / B control unit 41 is performing F / B control, the accelerator is depressed and calculated by combustion F / F control as shown by arrow A11. When the fuel injection amount is larger than the fuel injection amount calculated by the rotary F / B control, the switching unit 44 causes the combustion F / F control unit 42 to perform F / F control as shown by arrow A2. Switch control.

As shown by arrow A2 in FIG. 5, when the combustion F / F control unit 42 is performing F / F control, as shown by arrow A12, the pressure rise in the cylinder pressure of the internal combustion engine main body 14 is greater than a predetermined value. When it becomes large, the switching unit 44 switches the control so that the combustion F / B control unit 43 performs the F / B control as shown by the arrow A3.

As shown by arrow A3 in FIG. 5, when the combustion F / B control unit 43 is performing F / B control, as shown by arrow A21, the pressure rise in the cylinder pressure of the internal combustion engine main body 14 is equal to or less than a predetermined value. Then, as shown by the arrow A2, the switching unit 44 switches the control so that the combustion F / F control unit 42 performs the F / F control.

As shown by the arrow A2 in FIG. 5, when the combustion F / F control unit 42 is performing the F / F control, the rotation speed of the internal combustion engine main body 14 becomes the idle rotation speed as shown by the arrow A22. When the fuel injection amount calculated by the rotary F / B control is larger than the fuel injection amount calculated by the fuel F / F control, the switching unit 44 changes the rotary F / B control unit 41 as shown by an arrow A22. Switches the control so that F / B control is performed.

As described above, when the internal combustion engine main body 14 is in the idle state, the rotation F / B control unit 41 F so that the internal combustion engine main body 14 becomes the idle rotation speed based on the rotation speed of the internal combustion engine main body 14. / B control is performed. The combustion F / F control unit 42 rotates the internal combustion engine body 14 when the internal combustion engine body 14 is in a non-idle state and the pressure rise in the cylinder pressure of the internal combustion engine body 14 is near an idle value of a predetermined value or less. F / F control is performed so that the internal combustion engine main body 14 is in a desired combustion state based on the accelerator opening degree and the accelerator opening degree. When the internal combustion engine main body 14 is in the non-idle state and the pressure rise in the cylinder pressure of the internal combustion engine main body 14 is larger than a predetermined value, the combustion F / B control unit 43 is in the combustion F / B enabled state. F / B control is performed so that the internal combustion engine main body 14 is in a desired combustion state based on the in-cylinder pressure of. As a result, the ECU 40 can control the internal combustion engine main body 14 to an appropriate operating state so that the internal combustion engine main body 14 does not stall or the like even when the internal combustion engine main body 14 is in the idle state and the idle vicinity state.

Further, the calculation unit 51 of the combustion F / F control unit 42 calculates the fuel injection amount indicated value for the internal combustion engine main body 14 to be in a desired combustion state, and the filter 52 calculates the fuel injection by the calculation unit 51. Pass the low frequency component of the quantity indication value. As a result, the fuel injection amount indicated value output from the combustion F / F control unit 42 gradually changes, and the engine stall of the internal combustion engine main body 14 can be suppressed.

1 Internal combustion engine 11 Air cleaner 12 Turbocharger 13 Intercooler 14 Internal combustion engine body 21 Crank angle sensor 22 In-cylinder pressure sensor 23 Accelerator sensor 31 Intake passage 32 Exhaust passage 40 ECU
41 Rotation F / B control unit 42 Combustion F / F control unit 43 Combustion F / B control unit 44 Switching unit 45 Storage unit 51 Calculation unit 52 Filter

Claims (7)

When the internal combustion engine main body is in the non-idle state and the pressure rise in the cylinder pressure is in the first state of a predetermined value or less, the internal combustion engine main body moves based on the rotation speed of the internal combustion engine main body and the accelerator opening. A combustion feed forward control unit that performs feed forward control so as to obtain a desired combustion state,
When the internal combustion engine main body is in a non-idle state and the pressure rise of the in-cylinder pressure is in a second state larger than the predetermined value, the internal combustion engine main body is brought into a desired combustion state based on the in-cylinder pressure. Combustion feedback control unit that performs feedback control and
Internal combustion engine control device. The combustion feedforward control unit includes a calculation unit that calculates a fuel injection amount instruction value for the internal combustion engine main body to be in a desired combustion state.
A filter that passes the low frequency component of the fuel injection amount indicated value and
The control device for an internal combustion engine according to claim 1. When the internal combustion engine main body is in the first state and the pressure rise of the in-cylinder pressure becomes larger than the predetermined value, the combustion feedback control unit has a switching unit that switches the control so as to perform feedback control.
The control device for an internal combustion engine according to claim 1 or 2. When the internal combustion engine main body is in the second state and the pressure rise of the in-cylinder pressure becomes equal to or less than the predetermined value, the combustion feedforward control unit has a switching unit that switches the control so as to perform feedforward control. ,
The control device for an internal combustion engine according to any one of claims 1 to 3. It has a rotation feedback control unit that performs feedback control so that the internal combustion engine main body becomes an idle rotation speed based on the rotation speed of the internal combustion engine main body when the internal combustion engine main body is in an idle state.
The control device for an internal combustion engine according to any one of claims 1 to 4. When the accelerator is depressed when the internal combustion engine main body is in the idle state and the fuel injection amount calculated by the combustion feedforward control unit is larger than the fuel injection amount calculated by the rotation feedback control unit, the combustion It has a switching unit that switches the control so that the feedforward control unit performs feedforward control.
The control device for an internal combustion engine according to claim 5. When the internal combustion engine main body is in the first state, the rotation speed of the internal combustion engine main body becomes the idle rotation speed, and the fuel injection amount calculated by the rotation feedback control unit is calculated by the feedforward control unit. When the fuel injection amount is larger than the fuel injection amount, the rotation feedback control unit has a switching unit that switches the control so as to perform feedback control.
The control device for an internal combustion engine according to claim 5 or 6.