JPH08170549A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE: To provide the maximum charging efficiency by calculating a target valve closing timing according to the operating conditions detected by an operating condition detecting means and closing a valve at the target valve closing timing corrected by the amount of correction for the target valve closing timing to minimize the maximum air intake pipe pressure value detected by an air intake pipe pressure detecting means. CONSTITUTION: The detected signals from a throttle opening sensor 7 and a crank angle sensor 8 as operating condition detecting means are read so as to determine the optimum target air intake valve opening and closing timing for the conditions read from a map to be stored. On the other hand, air intake pipe pressure signals are read into a time series in synchronous with crank angle signals, their difference values are calculated, a change point of these values from positive to negative, i.e., a timing at which the air intake pressure becomes maximum is searched, and the pressure value at the change point is stored. Then the pressure values at the change point by the previous and this calculations are compared. When the value by this calculation is smaller, the amount of correction is increased from the previous calculation and, when the value by this calculation is larger, it is decreased, and the amount of correction is added to a target air intake valve closing timing so as to control a variable valve timing mechanism 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing adjusting device for an internal combustion engine having a variable valve timing mechanism.

[0002]

2. Description of the Related Art It is known to control a closing timing of an intake valve by using a variable valve timing mechanism so that an optimum charging efficiency can be obtained according to an operating state of an engine. Japanese Unexamined Patent Publication No. 101508 discloses that the average value of the intake negative pressure is detected and the closing timing of the intake valve is controlled so that it becomes a target value.

[0003]

By the way, the pressure in the intake pipe changes as shown in FIG. 2 depending on the closing timing of the intake valve, and the maximum pressure in the intake pipe is too early when the closing timing of the intake valve is too early. Also becomes larger due to the reflection of the intake air (C in Fig. 2
2) Moreover, even if the closing timing of the intake valve is too late, it will be increased by the blowback of the intake air (C3 in FIG. 2), and will be minimized by closing the valve at a certain optimum time (C in FIG. 2).
1) At this time, the filling efficiency becomes maximum. Conversely speaking, the charging efficiency can be maximized by adjusting the closing timing of the intake valve so that the maximum pressure in the intake pipe is minimized.

On the other hand, the pressure in the intake pipe changes as shown in FIG. 3 depending on the opening timing of the intake valve, and the minimum pressure in the intake pipe is due to exhaust blowback even if the opening timing of the intake valve is too early. 3 (O3 in FIG. 3), and even if the opening timing of the intake valve is too late, it increases due to interference with the pulsation in the intake system (O2 in FIG. 3). (O1 in FIG. 3), the filling efficiency becomes maximum at this time. Conversely speaking, the charging efficiency can be maximized by adjusting the opening timing of the intake valve so that the minimum pressure in the intake pipe is minimized. As described above, in order to maximize the filling efficiency by reducing the maximum pressure in the intake pipe or the minimum pressure in the intake pipe, the maximum pressure in the intake pipe or the minimum pressure must be accurately measured. It is necessary to catch it.

However, in the device of the above publication, the average value of the intake negative pressure is controlled as a parameter, and the maximum pressure or the minimum pressure in the intake pipe is not accurately grasped, so that the filling efficiency is maximized. I can't. In view of the above problems, the present invention provides a valve timing capable of obtaining the maximum filling efficiency by controlling the variable valve timing mechanism so that the maximum pressure or the minimum pressure in the intake pipe during the intake valve opening period is small. An object is to provide a control device.

[0006]

According to claim 1 of the present invention, as shown in FIG. 1A, a variable valve timing mechanism for changing the opening / closing timing of an intake valve and an engine operating state are detected. Operating state detecting means, a target valve closing timing calculating means for calculating a target valve closing timing of the intake valve for obtaining the maximum charging efficiency in the engine operating state detected by the operating state detecting means, and an intake pressure in the intake pipe. Intake pipe pressure detection means, an intake pipe pressure maximum value calculation means for calculating the maximum value of the intake pipe pressure detected by the intake pipe pressure detection means, and an intake pipe calculated by the intake pipe pressure maximum value calculation means A target valve closing timing correcting means for correcting the target valve closing timing so that the maximum value of the pressure is minimized, and an intake valve is closed at the target valve closing timing corrected by the target valve closing timing correcting means. Variable valve timing Valve timing control device is provided consisting of an intake valve timing adjustment means for controlling the mechanism.

According to the second aspect, as shown in FIG. 1B, a variable valve timing mechanism for changing the opening / closing timing of the intake valve, an operating state detecting means for detecting an engine operating state, and the operating state. Target opening timing calculation means for calculating the target opening timing of the intake valve for obtaining the maximum charging efficiency in the engine operating state detected by the state detection means, and intake pipe pressure detection means for detecting the intake pressure in the intake pipe , An intake pipe pressure maximum value calculating means for calculating a maximum value of the intake pipe pressure detected by the intake pipe pressure detecting means, and a minimum value of the intake pipe pressure calculated by the intake pipe pressure minimum value calculating means are minimized. Target valve opening timing correction means for correcting the target valve opening timing, and an intake valve for controlling the variable valve timing mechanism so as to open the intake valve at the target valve opening timing corrected by the target valve opening timing correction means. Open Valve timing control apparatus is provided comprising a valve timing control apparatus and comprising a timing adjusting unit.

[0008]

According to the first aspect of the present invention, the target valve closing timing calculation means calculates the target valve closing timing of the intake valve for obtaining the maximum charging efficiency in the engine operating state detected by the operating state detecting means, and the intake pipe The maximum pressure value calculating means calculates the maximum value of the intake pipe pressure detected by the intake pipe pressure detecting means. The target valve closing timing correction means calculates a correction amount of the target valve closing timing for minimizing the maximum value of the intake pipe pressure, and closes the intake valve at the target valve closing timing corrected by the correction amount. Thus, the intake valve opening / closing timing adjusting means controls the variable valve timing mechanism.

According to the second aspect of the present invention, the target valve opening timing calculating means calculates the target opening timing of the intake valve for obtaining the maximum charging efficiency in the engine operating state detected by the operating state detecting means, and the intake pipe The minimum pressure value calculation means calculates the minimum value of the intake pipe pressure detected by the intake pipe pressure detection means. The target valve opening timing correction means calculates a correction amount of the target valve opening timing for minimizing the minimum value of the intake pipe pressure, and opens the intake valve at the target valve opening timing corrected by the correction amount. Thus, the intake valve opening / closing timing adjusting means controls the variable valve timing mechanism.

[0010]

Next, an embodiment of the present invention will be described. FIG. 4 is a diagram showing the configuration of the embodiment of the present invention. Engine 1
Is provided with an intake valve 2 and an exhaust valve 3, and a cam shaft (not shown) that drives the intake valve 2 rotates in synchronization with a crank shaft. A variable valve timing mechanism (hereinafter referred to as VVT) for changing the phase of the camshaft to adjust the opening / closing timing of the intake valve and optimizing the intake characteristic so that the maximum engine performance can be obtained according to the engine operating conditions.
4) is provided. The VVT 4 may be, for example, one in which a helical gear is interposed between a cam pulley (not shown) and a cam shaft (not shown) to change the phase. However, the method is not important in the present invention, and therefore the details are omitted. Reference numeral 5 is an intake pipe, 6 is an intake pipe pressure sensor, 7 is a throttle opening sensor, and 8 is a crank angle sensor. ECC
Reference numeral 100 denotes an input interface 101, an A / D converter 102, a CPU 103, a RAM 104, a ROM 105,
The output interface 106 and the like are included.

Since the intake pipe pressure sensor 6 detects the pressure in the intake pipe, it serves as intake pressure detecting means in the present invention.
The output is input through the input interface 101 and the A / D converter 102, and is stored in the RAM 104 as time-series data synchronized with the signal of the crank angle sensor 8. Throttle opening sensor 7 and crank angle sensor 8
Since the throttle opening and the engine speed, which are indicators of the driving state, are detected from the above, these two sensors serve as a driving state detecting means.

According to the first aspect of the present invention, the CPU 103 has the target valve closing timing of the intake valve for obtaining the maximum filling efficiency in accordance with the operating conditions detected by the throttle opening sensor 7 and the crank angle sensor 8 which are operating state detecting means. Is calculated, and the maximum value of the intake pipe pressure detected by the intake pipe pressure sensor 6 which is the intake pipe pressure detecting means is calculated as a difference to correct the target valve closing timing for minimizing the maximum value of the intake pipe pressure. Calculate the amount,
Since the intake valve opening / closing timing is adjusted so that the intake valve is closed by the target valve closing timing corrected by the correction amount,
It functions as the target valve closing timing calculating means, the intake pipe pressure maximum value differential calculating means, the target valve closing timing correcting means, and the intake valve opening / closing timing adjusting means.

Further, in the second aspect of the present invention, similarly, the target of the intake valve for obtaining the maximum charging efficiency in accordance with the operating conditions detected by the throttle opening sensor 7 and the crank angle sensor 8 which are operating state detecting means. The target valve opening for calculating the valve opening timing and differentiating the minimum value of the intake pipe pressure detected by the intake pipe pressure sensor 6 which is the intake pipe pressure detecting means to minimize the minimum value of the intake pipe pressure. Calculate the correction amount of the time,
Since the intake valve opening / closing timing is adjusted so that the intake valve is opened at the target valve opening timing corrected by the correction amount,
It functions as the target valve closing timing calculating means, the intake pipe pressure maximum value differential calculating means, the target valve closing timing correcting means, and the intake valve opening / closing timing adjusting means.

Next, the operation of the ECC 100 according to the first embodiment will be described with reference to the flow charts shown in FIGS. First, in step 101, the Ne and throttle opening TA of the engine currently in operation are read, and step 1
In 02, the optimum target intake valve closing timing IVCT for the conditions read in step 101 from the map stored in advance in the ROM is set. In step 103, the intake pipe pressure signal is synchronized with the crank angle signal and read in time series, and in step 104, the difference value is calculated. In step 105, the change point of the difference value from positive to negative, that is,
The time IVCAi at which the actual intake pressure becomes maximum is searched for. In step 106, the pressure value Pcmax (i) at the change point obtained in step 105 is stored.

In step 107, the pressure value Pcmax (i) at the change point calculated by the current calculation is compared with the pressure value Pcmax (i-1) at the change point calculated by the previous calculation. If the calculated value of this time is larger, the process proceeds to step 111. If they are equal, the process proceeds to step 114.

If the process proceeds to step 108, it means that the previous value is out of the desired value as compared with this time and the correction amount of the previous time is insufficient, and this time it is necessary to further increase the correction amount. This means that the previous correction value Di-1 is positive (including the case where it is equal) in step 108.
Whether the result is positive or negative, and if the result of determination is positive, in order to increase the value to the positive side, Di = Di-1 + d is set in step 109 and the process proceeds to step 115. If the result of determination is negative, the value is negative. Proceed to step 110 to increase to D
i = Di-1 -d is set and the operation proceeds to step 115. here,
d is a correction value for correcting the correction value and is a predetermined constant positive value.

On the other hand, when the process proceeds to step 111, this time is more deviated from the desired value than the previous time, and the correction amount of the previous time is too large. Therefore, it is necessary to reduce the correction amount of the previous time. This means that in step 111, it is determined whether Di-1 is positive (including the case where it is equal) or negative. If the determination result is positive, the process proceeds to step 112 to reduce the positive amount. If Di = Di-1 -d, the process proceeds to step 115, and if the determination result is negative, the process proceeds to step 113 and Di is set to reduce the negative amount.
= Di-1 + d and the process proceeds to step 115. Step 1
If the process proceeds to step 14, it means that the same correction amount as that of the previous time is sufficient, so that Di = Di-1 is set in step 114 and the process proceeds to step 115. Then, at step 115, the command valve closing timing IVCi = IVCT + Di is set, and the routine proceeds to step 116, where the command valve closing timing IVCi is instructed to the VVT drive unit.

As described above, in the first embodiment, step 10 is performed.
4, 105, the maximum value of the intake pressure is obtained by obtaining the change point of the difference value of the intake pipe pressure signal from positive to negative, and the closing timing of the intake valve is set so that the maximum value is obtained. Therefore, the maximum charging efficiency can be obtained without providing any detection means other than the commonly used intake pipe pressure sensor.

Next, the second embodiment will be described. The structure of the second embodiment is the same as that of the first embodiment, and only the control method is different. Hereinafter, the second shown in FIG. 7 and FIG.
A control flowchart of the embodiment will be described. First, in step 201, Ne and throttle opening TA of the engine currently in operation are read, and in step 202, ROM is read beforehand.
The optimum target intake valve opening timing IVOTi for the conditions read in step 201 is set from the map stored in step S201.

In step 203, the intake pipe pressure signal is synchronized with the crank angle signal and read in time series.
In 04, the difference value is calculated. In step 205, a changing point of the difference value from negative to positive, that is, a timing IVOAi at which the actual intake pressure becomes minimum is searched. Step 20
6, the pressure value Pcmi at the change point obtained in step 205
Save n (i). In step 207, the pressure value Pcmin (i) at the change point calculated by the current calculation is compared with the pressure value Pcmin (i-1) at the change point calculated by the previous calculation. If the calculated pressure value Pcmin (i-1) is smaller, the process proceeds to step 208. If the current calculation is larger, the process proceeds to step 211, and if they are equal, the process proceeds to step 214.

If the process proceeds to step 208, it means that the previous value is out of the desired value as compared with this time, and the correction amount of the previous time is insufficient. Therefore, it is necessary to further increase the correction amount of this time. This means that the previous correction value Di-1 is positive (including the case where it is equal) in step 208.
Whether the value is negative or negative, and if the result of determination is positive, in order to increase the value to the positive side, Di = Di-1 + d is set in step 209 and the process proceeds to step 215. If the result of determination is negative, the value is negative. Proceed to step 210 to increase to D
i = Di-1 -d is set and the process proceeds to step 215.

On the other hand, when the process proceeds to step 211, this time is more deviated from the desired value than the last time, and the correction amount of the previous time is too large. Therefore, it is necessary to reduce the correction amount of the previous time. This means that in step 211, it is determined whether Di-1 is positive (including the case where it is equal) or negative. If the determination result is positive, the process proceeds to step 212 to reduce the positive amount. If Di = Di-1 -d, the process proceeds to step 215, and if the determination result is negative, the process proceeds to step 213, where Di is set in order to reduce the negative amount.
= Di-1 + d, the process proceeds to step 215. Step 2
In the case of advancing to 14, it means that the same correction amount as the previous time is sufficient, so that Di = Di-1 is set in step 214, and the process proceeds to step 215. Then, at step 215, the command valve opening timing IVOi = IVOT + Di is set, and the routine proceeds to step 216, where the command valve opening timing IVOi is instructed to the VVT drive unit.

As described above, in the second embodiment, step 20 is performed.
4, 205, the minimum value of the intake pressure is obtained by obtaining the change point of the difference value of the intake pipe pressure signal from negative to positive, and the intake valve opening timing is set so that the minimum value is obtained. Therefore, the maximum charging efficiency can be obtained without providing any detection means other than the commonly used intake pipe pressure sensor. In both the first and second embodiments, the difference between the intake pipe pressure signals is calculated in order to accurately determine the maximum value or the minimum value of the intake pressure together with the generation timing, but it can be accurately determined. Other methods may be used as long as they are available.

[0024]

According to the present invention, since the maximum value or the minimum value of the intake pipe pressure is obtained and controlled so as to minimize the value, the maximum filling efficiency can be obtained accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing a concept of control of each claim of the present invention, (A) is a block diagram showing a concept of control of claim 1 of the present invention, and (B) is a claim of the present invention. It is a block diagram which shows the concept of 2 control.

FIG. 2 is a diagram showing changes in the maximum value of intake pressure when the closing timing of the intake valve is changed.

FIG. 3 is a diagram showing changes in the minimum value of intake pressure when the opening timing of the intake valve is changed.

FIG. 4 is a configuration diagram of an embodiment of the present invention.

FIG. 5 is a flow chart for explaining the operation of the control circuit of the first embodiment.

FIG. 6 is a flowchart for explaining the operation of the control circuit of the first embodiment.

FIG. 7 is a flow chart for explaining the operation of the control circuit of the second embodiment.

FIG. 8 is a flow chart for explaining the operation of the control circuit of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Intake valve 3 ... Exhaust valve 4 ... Variable valve timing mechanism (VVT) 5 ... Intake pipe 6 ... Intake pipe pressure sensor 7 ... Throttle opening sensor 8 ... Crank angle sensor 100 ... Engine control computer (ECC) 101 ... Input interface 102 ... A / D converter 103 ... CPU 104 ... RAM 105 ... ROM 106 ... Output interface

Claims (2)

[Claims] 1. A variable valve timing mechanism for changing the opening / closing timing of an intake valve, an operating state detecting means for detecting an engine operating state, and a maximum filling efficiency in the engine operating state detected by the operating state detecting means. Target closing timing calculating means for calculating the target closing timing of the intake valve, intake pipe pressure detecting means for detecting the intake pressure in the intake pipe, and the maximum value of the intake pipe pressure detected by the intake pipe pressure detecting means. An intake pipe pressure maximum value calculation means for calculating; a target valve closing timing correction means for correcting the target valve closing timing so that the maximum value of the intake pipe pressure calculated by the intake pipe pressure maximum value calculation means is minimized; A valve timing control comprising an intake valve opening / closing timing adjusting means for controlling the variable valve timing mechanism so as to close the intake valve at the target valve closing timing corrected by the target valve closing timing correcting means. Control device. 2. A variable valve timing mechanism for changing the opening / closing timing of an intake valve, an operating state detecting means for detecting an engine operating state, and a maximum filling efficiency in the engine operating state detected by the operating state detecting means. Target opening timing calculation means for calculating the target opening timing of the intake valve, intake pipe pressure detecting means for detecting the intake pressure in the intake pipe, and the minimum value of the intake pipe pressure detected by the intake pipe pressure detecting means. Intake pipe pressure minimum value calculation means for calculating; target valve opening timing correction means for correcting the target valve opening timing so that the minimum value of the intake pipe pressure calculated by the intake pipe pressure minimum value calculation means is minimized; A valve timing control comprising an intake valve opening / closing timing adjusting means for controlling the variable valve timing mechanism so as to open the intake valve at the target valve opening timing corrected by the target opening timing correcting means. Control device.