JP4080551B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine provided with an electromagnetically driven intake valve and / or an exhaust valve.
[0002]
[Prior art]
A basic configuration of an internal combustion engine in which an intake valve and / or an exhaust valve is driven by a spring and a solenoid is shown in US Pat. No. 3,882,833. Further, as a control device for an internal combustion engine adopting such a basic configuration, there has been conventionally known an apparatus in which the output timing of a drive signal supplied to a valve drive solenoid is changed according to the engine speed ( JP-A-2-112606).
[0003]
In addition, in the above basic configuration, an electromagnetic valve having an improved structure of an electromagnetic drive mechanism has been proposed (U.S. Pat. No. 5,222,714) in order to minimize the required electromagnetic force of the solenoid.
[0004]
[Problems to be solved by the invention]
However, none of the above conventional techniques has a function of determining an abnormality of the electromagnetic drive mechanism of the intake valve and / or the exhaust valve. There is a risk that contact between the piston and the piston may occur, or the fuel supplied to the combustion chamber is discharged as it is and the exhaust gas characteristics are deteriorated.
[0005]
The present invention has been made paying attention to this point, and determines abnormality of the electromagnetically driven intake valve and / or the exhaust valve. An object of the present invention is to provide a control device for an internal combustion engine that can prevent deterioration.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an electromagnetic drive means for opening and closing at least one of an intake valve and an exhaust valve of an internal combustion engine by an electromagnetic force, and an accelerator pedal for detecting a depression amount of an accelerator pedal of a vehicle on which the engine is mounted. In the control apparatus for an internal combustion engine, comprising: a depressing amount detection means; an engine operation state detection means for detecting an engine operation state including at least the engine speed; and a fuel supply means for supplying fuel to the engine. was in accordance with the accelerator pedal depression amount and the engine operating condition, said calculating said at least one opening and closing valve timing of the intake valves and exhaust valves by the electromagnetic drive means, controlling said electromagnetic driving means in accordance with the opening and closing timings of the calculated and valve control means for, as an actual closing valve timing at least one of the intake and exhaust valves by the valve opening and closing control unit, The actual closing valve timing detecting means for detecting the valve operation start timing and the valve-opening operation start timing, according to the rotation speed of the detected accelerator pedal depression amount and the engine, at least the limit of one of the opening and closing of the intake and exhaust valves Limit timing setting means for setting the valve-opening limit value and the valve-closing limit value as timing, and when the detected valve-opening operation start timing is on the advance side of the set valve-opening limit value In addition, when the electromagnetic driving means is determined to be abnormal and the detected valve closing operation start timing is on the retard side with respect to the set valve closing side limit value, the electromagnetic driving means is abnormal. And an abnormality determining means for determining that it is.
[0007]
Further, the electromagnetic drive means is configured to open and close both the intake valve and the exhaust valve, when said electromagnetic drive means is determined to be abnormal, the valve opening and closing control unit, the corresponding the intake valve and the exhaust valve of the cylinder which is closed actuation, the fuel supply means, he is desirable to stop the supply of fuel to the corresponding cylinder.
[0008]
[Action]
According to the control apparatus according to claim 1, as an actual closing valve timing of at least one of the intake and exhaust valves are driven by electromagnetic drive means, the valve opening operation start timing and the valve-opening start timing module is detected. Further, a valve opening side limit value and a valve closing side limit value are set as the limit timing of at least one of the intake valve and the exhaust valve according to the detected accelerator pedal depression amount and the engine speed. When the detected valve opening operation start timing is on the advance side of the set valve opening side limit value, it is determined that the electromagnetic drive means is abnormal, and the detected valve closing operation start timing is Is on the retard side with respect to the set valve-closing limit value, it is determined that the electromagnetic drive means is abnormal.
[0009]
According to the control apparatus according to claim 2, when it is determined that the abnormality of the electromagnetic drive means, with both the intake valve and the exhaust valve is electromagnetically driven corresponding cylinder is closed, the fuel to the corresponding cylinder Supply is stopped.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
FIG. 1 is a sectional view showing the structure of an electromagnetically driven intake valve 10 according to an embodiment of the present invention. The intake valve 10 includes a valve body 2 to which an armature 4 is fixed and a valve drive unit 1 that drives the valve body 2. A combustion chamber is connected via a valve guide 3 to open and close the intake port 8 of the combustion chamber of the internal combustion engine. Mounted on top. An exhaust valve (not shown) has the same structure and is mounted on the upper portion of the combustion chamber so as to open and close the exhaust port of the combustion chamber.
[0012]
The valve drive unit 1 includes two opposing solenoids (electromagnets), that is, a valve closing solenoid 5 that biases the valve body 2 in the valve closing direction, a valve opening solenoid 6 that biases the valve body 2 in the valve opening direction, and a spring. 7 is the main component. The valve closing solenoid 5 includes a coil 5a and a magnetic body 5b, and the valve opening solenoid 6 includes a coil 6a and a magnetic body 6b. When the armature 4 is in the neutral position BP, the spring 7 urges the valve body 2 in the valve opening direction when the urging force against the valve body 2 is zero, and when the arm 7 is positioned above the neutral position BP, the spring 7 When positioned below, the valve body 2 is configured to be biased in the valve closing direction.
[0013]
According to the above configuration, when the valve closing solenoid 5 or the valve opening solenoid 6 is energized, the valve body 2 is between the fully closed position where the intake port 8 is closed and the fully open position where the lift amount of the valve body is maximum. To move. When the solenoids 5 and 6 are not energized, the valve body 2 is located at a neutral position between the fully closed position and the fully open position.
[0014]
FIG. 2 is a diagram showing the configuration of the intake valve 10 and its control device. The valve drive unit 1 includes a position sensor 11 for detecting the position of the armature 4 and a temperature for detecting the coil temperature TCOIL of the valve opening solenoid 6. A sensor 12 is provided, and detection signals thereof are supplied to a CPU (central processing unit) 16 and an energization time / timing control circuit unit 14 via an input / output interface 13. Further, a sensor group (not shown) is connected to the input / output interface 13, and the engine speed NE, the accelerator pedal depression amount (hereinafter referred to as “accelerator opening”) θACC, and the engine water temperature TW of the vehicle on which the engine is mounted. , A signal indicating the intake air temperature TA, the battery voltage VB, etc., a signal indicating the rotation angle of the crankshaft, a signal indicating ON / OFF of the ignition switch, and the like are input to the CPU 16 and the energization time / timing control circuit unit 14 Is done. In this embodiment, a signal pulse indicating a predetermined crank angle position of a specific cylinder of the engine (hereinafter referred to as “CYL signal pulse”) is generated as a signal indicating the rotation angle of the crankshaft, and one pulse is generated every 720 ° of the crank angle. And a signal pulse (hereinafter referred to as “CRK signal pulse”) generated at a cycle of a crank angle of 30 ° is input.
[0015]
The CPU 16 is connected to a ROM 17 that stores programs executed by the CPU 16 and a RAM 18 that stores data in the middle of calculation, sensor detection data, and the like. The energizing time / timing control circuit unit 14 is connected to a timer counter 19 having a function as a timer. The timer counter 19 is connected to the CPU 16 and the count value is set by the CPU 16. Is called.
[0016]
The energizing time / timing control circuit unit 14 is connected to the driver circuit 15, the valve closing solenoid drive circuit 15 a of the driver circuit 15 is the coil 5 a of the valve closing solenoid 5, and the valve opening solenoid drive circuit 15 b is the coil of the valve opening solenoid 6. Each is connected to 6a. A battery 20 is connected to the driver circuit 15, and power is supplied from the battery 20. The control circuit unit 14 controls current supply (energization) to the coils 5a and 6a.
[0017]
Note that the power supply voltage is supplied from the battery 20 via a power supply circuit (not shown) to other circuits such as the CPU 16, the ROM 17, and the input / output interface 13 other than the driver circuit 15.
[0018]
The engine of the present embodiment is a four-cylinder engine in which each cylinder is provided with two intake valves and two exhaust valves, and all 16 valves are electromagnetically driven. Therefore, the energization time / timing control circuit unit 4, the driver circuit 15, and the timer counter 19 of FIG. 2 are provided corresponding to each of the 16 valves.
[0019]
The CPU 16 determines the opening timing and closing timing of the intake valve and the exhaust valve according to input signals from various sensors, and sets the timer counter 19 corresponding to each intake / exhaust valve.
[0020]
Further, a fuel injection valve (not shown) is provided for each cylinder in the intake pipe of the engine of the present embodiment, and the valve opening control of the fuel injection valve and the ignition command signal to the ignition plug of each cylinder are provided. The output control is performed by the CPU 16.
[0021]
FIG. 3 is a flowchart of an intake valve / exhaust valve open / close control routine executed by the CPU 16, and FIG. 4 shows the valve lift amount of the intake / exhaust valve and the voltage applied to the valve opening solenoid 6 and the valve closing solenoid 5. It is a figure for demonstrating a relationship. First, the outline of energization control of each solenoid will be described with reference to FIG.
[0022]
In this embodiment, when the intake / exhaust valve is opened, energization of the valve opening solenoid 6 is started at a time (θOPENON) just before the first overlap period A from the end of energization of the valve closing solenoid 5 (θCLOSEOFF). . As a result, the valve body 2 starts the valve opening operation, and quickly and reliably moves to the fully opened position when the valve closing solenoid 5 is energized. Further, during the valve closing operation, the energization of the valve closing solenoid 5 is started at a time point (θCLOSESE) that is before the second overlap period B from the end of energization of the valve opening solenoid 6 (θOPENOFF). As a result, the valve body 2 starts the valve closing operation, and quickly and reliably moves to the fully closed position when the valve opening solenoid 5 is energized.
[0023]
Next, a specific method for calculating the energization start / end timing of each solenoid will be described with reference to FIG.
[0024]
In step S1 of FIG. 3, it is determined whether or not an abnormality determination flag FEVAFS (N) indicating that there is an abnormality in the opening / closing operation timing of the intake valve or the exhaust valve is “1”. This abnormality determination flag FEVAFS (N) is set for each cylinder in an abnormality determination routine of FIG. 9 described later, and (N) is attached to indicate that it is a flag set for each cylinder. .
[0025]
If FEVAFS (N) = 1 in step S1 and it is determined that there is an abnormality in the opening / closing timing of the intake valve or exhaust valve of the Nth cylinder, the closing command signal for the intake valve and exhaust valve of that Nth cylinder Is output (step S2), and this routine is terminated. At the same time, control for stopping the fuel supply to the cylinder is performed.
[0026]
If the answer to step S1 is negative (NO), that is, FEVAFS (N) = 0, the process proceeds to step S3, and the energization end timing θCLOSEOFF of the valve closing solenoid 5 is set according to the accelerator opening θACC and the engine speed NE. It is calculated by searching the set map. Next, the energization start timing θOPENON of the valve opening solenoid 6 is calculated by the following equation (step S4).
[0027]
θOPENON = θCLOSEOFF-A
Here, as shown in FIG. 5, the first overlap period A is set according to the engine speed NE and the coil temperature TCOIL (specifically, a map set according to the NE value and the TCOIL value). Is calculated by searching for).
[0028]
In the subsequent step S5, as in step S3, the energization end timing θOPENOFF of the valve opening solenoid 6 is calculated by searching a map set according to the accelerator opening θACC and the engine speed NE. Next, the energization start timing θCLOSEON of the valve closing solenoid 5 is calculated by the following equation.
[0029]
θCLOSEON = θOPENOFF-B
Here, as shown in FIG. 5, the second overlap period B is set according to the engine speed NE and the coil temperature TCOIL by map search, as in the first overlap period A.
[0030]
Next, an intake / exhaust valve opening / closing valve timing correction routine (step S7) and an opening / closing valve solenoid energization processing routine (step S8) are executed, and this processing is terminated.
[0031]
FIG. 6 is a flowchart of the intake / exhaust valve opening / closing valve timing correction routine. First, in step S11, the coil temperature TCOIL and the battery voltage VB are read, and then the energization start / end timing of the valve closing solenoid 5 and the valve opening solenoid 6 is read. Is corrected according to the coil temperature TCOIL and the battery voltage VB (step S12). Specifically, as shown in FIG. 7, the energization start / end timing of each solenoid is corrected so as to be on the advance side as the coil temperature TCOIL increases or the battery voltage VB decreases.
[0032]
FIG. 8 is a flowchart of the on-off valve solenoid energization processing routine in step S8 of FIG. 3. This routine performs actual energization processing according to the calculated energization start / end timing of each solenoid. At this time, the intake valve and the exhaust valve to be opened are the intake valves of the cylinders in the intake stroke and the exhaust valves of the cylinders in the exhaust stroke, respectively.
[0033]
First, it is determined whether or not the energization start timing θOPENON of the valve opening solenoid 6 is reached (step S21). When the answer is affirmative (YES), the energization of the valve opening solenoid 6 is started (step S23) and then the valve is closed. It is determined whether the energization end timing θCLOSEOFF of the solenoid 5 (step S23). If the answer is affirmative (YES), the energization of the valve closing solenoid 5 is terminated (step S24), and then the valve closing solenoid 5 It is determined whether or not the energization start timing is θCLOSES (step S25). When the answer is affirmative (YES), energization of the valve closing solenoid 5 is started (step S26), and then the energization end timing of the valve opening solenoid 6 is reached. It is determined whether or not θOPENOFF (step S27). When the answer is affirmative (YES), energization of the valve opening solenoid 6 is terminated (step S27). Flop S28).
[0034]
When it does not correspond to each energization start / end time, this processing is immediately ended.
[0035]
FIG. 9 is a flowchart of a routine for determining an abnormality in the opening / closing operation timing of the intake / exhaust valve.
[0036]
First, in step S31, a map set according to the accelerator opening degree θACC and the engine speed NE is searched to determine the valve opening side limit value θLMTOPEN and the valve closing side limit value θLMTCLOSE. Next, the actual valve opening operation start timing θACTOPEN and the valve closing operation start timing θACTCLOSE (see FIG. 4A) of the valve element 2 are detected from the output of the position sensor 11 (step S32). In the subsequent step S33, limit checks of the detection times θACTOPEN and θACTCLOSE are performed.
[0037]
Specifically, the valve-opening start timing θACTOPEN and closing valve operation start timing ShitaACTCLOSE, respectively compared to the valve-opening limit value θLMTOPEN and the closing-side limit value ShitaLMTCLOSE, when θACTOPEN value is on the advance side of θLMTOPEN value When the θACTCLOSE value is on the retard side of the θLMTCLOSE value, it is determined that the limit check is NG (see the broken line in FIG. 4A).
[0038]
When the limit check is OK, this routine is immediately terminated. When it is NG, the abnormality determination flag FEVAFS (N) is set to “1” (step S34), and this routine is terminated.
[0039]
According to this routine, it is possible to accurately determine the deviation in the opening / closing timing of the intake / exhaust valves caused by the deterioration or failure of the intake / exhaust valves and their drive systems.
[0040]
Further, in this embodiment, when the intake / exhaust valve opening / closing timing is determined to be abnormal, the intake / exhaust valve of the corresponding cylinder is closed and the fuel supply to the corresponding cylinder is stopped. It is possible to prevent damage due to contact between the valve and the piston, etc., and further prevent unburned gas from being blown out, thereby suppressing deterioration of exhaust gas characteristics.
[0041]
In the above-described embodiment, the flag FEVAFS (N) = 1 is determined in step S1 of FIG. 3 and the intake / exhaust valve of only the corresponding cylinder is controlled to close, and the fuel supply to the corresponding cylinder is stopped. The flag FEVAFS (N) = 1 for any cylinder is determined, or the flag FEVAFS (N) = 1 for a predetermined number of cylinders (for example, two) or more, and the intake / exhaust valves of all cylinders are closed. Control may be performed so that fuel supply to all cylinders is stopped.
[0042]
【The invention's effect】
As described above in detail, according to the control device of the first aspect, the actual opening / closing valve timing of at least one of the intake valve and the exhaust valve driven by the electromagnetic drive means is detected, and the detected opening / closing valve timing is set to a predetermined value. Since the abnormality of the electromagnetic driving means is determined according to the comparison result with the limit timing, it is possible to accurately determine the deviation of the opening / closing valve timing of the intake valve and / or the exhaust valve due to the abnormality of the electromagnetic driving means.
[0043]
According to the control device of the second aspect, when it is determined that the electromagnetic driving means is abnormal, at least one of the electromagnetically driven intake valve and the exhaust valve is regulated to be closed, and the fuel supply is stopped. Therefore, it is possible to prevent damage due to contact between the intake valve and / or the exhaust valve and the piston, etc., and further prevent unburned gas from being blown out, thereby suppressing deterioration of exhaust gas characteristics.
[Brief description of the drawings]
FIG. 1 is a view showing the structure of an electromagnetically driven intake valve according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of an intake valve and a control device thereof in FIG.
FIG. 3 is a flowchart of an intake / exhaust valve opening / closing control routine;
FIG. 4 is a diagram for explaining the relationship between an intake / exhaust valve drive signal and a valve lift amount;
FIG. 5 is a diagram for explaining a setting tendency of an overlap period (A, B) calculation map;
FIG. 6 is a flowchart of an intake / exhaust valve opening / closing valve timing correction routine.
FIG. 7 is a diagram showing a tendency of correction of on-off valve timing.
FIG. 8 is a flowchart of an on-off valve solenoid energization processing routine.
FIG. 9 is a flowchart of an abnormality determination routine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Valve drive part 5 Valve closing solenoid 6 Valve opening solenoid 7 Spring 10 Intake valve 11 Position sensor 12 Coil temperature sensor 16 CPU

Claims (2)

An electromagnetic drive means for opening and closing at least one of an intake valve and an exhaust valve of the internal combustion engine by electromagnetic force; an accelerator pedal depression amount detection means for detecting an accelerator pedal depression amount of a vehicle in which the engine is mounted; and at least the engine In a control device for an internal combustion engine, comprising: an engine operating state detecting unit that detects an engine operating state including a rotational speed; and a fuel supply unit that supplies fuel to the engine.
According to the accelerator pedal depression amount and the engine operating state and the detection, said calculating said at least one opening and closing valve timing of the intake valves and exhaust valves by the electromagnetic driving means, said electromagnetic driving means in accordance with the opening and closing timings of the calculated Valve opening / closing control means for controlling
As a practical opening and closing valve timing of said at least one of the intake and exhaust valves by the valve opening and closing control unit, the actual closing valve timing detecting means for detecting the valve opening operation start timing and the valve-opening operation start timing,
Limit timing setting means for setting a valve-opening side limit value and a valve-closing side limit value as the limit timing of opening and closing of the at least one of the intake valve and the exhaust valve according to the detected accelerator pedal depression amount and engine speed When,
When the detected valve opening operation start timing is on the advance side with respect to the set valve opening side limit value, it is determined that the electromagnetic drive means is abnormal, and the detected valve closing operation start is started. An internal combustion engine control apparatus , comprising: an abnormality determining unit that determines that the electromagnetic driving unit is abnormal when the timing is on the retard side of the set valve closing side limit value . Cylinder said electromagnetic drive means, the is configured to open and close both the intake valve and the exhaust valve, when said electromagnetic drive means is determined to be abnormal, the valve opening control means, the appropriate is closed actuating the intake valve and the exhaust valve, said fuel supply means, the control apparatus for an internal combustion engine according to claim 1, wherein the stopping the supply of fuel to the corresponding cylinder.

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