JP4082486B2 - Control device for electronically controlled throttle engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electronically controlled throttle engine that eliminates a difference between a mechanical opening of a throttle valve and an opening instruction value caused by temperature characteristics of a throttle sensor.
[0002]
[Prior art]
In a conventional engine control system in which an accelerator pedal and a throttle valve are mechanically connected by a cable or the like, an intake air amount or an intake pipe pressure at a throttle opening determined according to an accelerator pedal depression amount is measured. Engine control such as fuel injection control and ignition timing control is performed by setting the fuel injection amount and ignition timing based on the intake air amount or intake pipe pressure.
[0003]
On the other hand, recently, a so-called drive-by-wire control system has been developed in which the driving operation of the vehicle is electrically detected to control traveling. In this drive-by-wire engine control system, as disclosed in, for example, Japanese Patent Laid-Open No. 11-36954, an electronically controlled throttle valve that is driven to open and close by a motor or the like is employed. Feedback control is performed to achieve the target opening. At this time, the opening degree of the throttle valve is detected based on the learned value of the throttle sensor when the throttle valve is positioned at the reference position.
[0004]
[Problems to be solved by the invention]
However, in general, since the sensor output changes depending on the temperature, even if the reference position of the throttle valve is learned, if the temperature changes, the throttle opening based on the throttle sensor output and the actual mechanical opening It will not match.
[0005]
In particular, during idle operation in which the throttle valve is controlled near the fully closed point, as shown in FIG. 5, the opening that occurs between the target opening and the actual mechanical opening is caused by the temperature characteristics of the throttle sensor. Even if trying to give the same amount of air required for idle operation with the same opening instruction value due to the degree of deviation, the actual air amount becomes excessive and the convergence to the target rotation speed deteriorates, or conversely There is a problem that the engine speed becomes unstable due to a shortage of the amount and the target rotational speed is not reached, causing a drop in rotation.
[0006]
The present invention has been made in view of the above circumstances, and eliminates the deviation between the mechanical opening of the throttle valve and the opening instruction value caused by the temperature characteristics of the throttle sensor, thereby reducing the controllability. An object of the present invention is to provide a control device for an electronically controlled throttle engine that can be prevented.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is based on a signal from a throttle sensor for detecting the opening degree of the throttle valve so that the opening degree of the throttle valve matches the opening degree instruction value. An electronically controlled throttle engine control device that controls the opening and closing of the throttle valve, and corresponds to an actual air amount passing through the throttle valve and an opening instruction value of the throttle valve in an idle operation state when a learning condition is satisfied Means for learning the amount of deviation between the calculated air amount and the actual air amount passing through the throttle valve and the throttle valve opening instruction value in an idle operation state other than the idle operation state when the learning condition is satisfied It means for calculating a deviation amount between the calculated air amount corresponding to, on the basis of the difference between the two shift amount to correct the opening degree command value of the throttle valve Characterized by comprising a means for calculating an opening degree correction value.
[0008]
The invention described in claim 2 is characterized in that, in the invention described in claim 1, the opening correction value is gradually increased or decreased so that the difference between the deviation amounts is within a set range.
[0009]
That is, the invention according to claim 1 learns a deviation amount between the actual air amount passing through the throttle valve and the calculated air amount corresponding to the opening instruction value of the throttle valve in the idle operation state when the learning condition is satisfied. In addition, in the idle operation state other than the idle operation state when the learning condition is satisfied, the amount of deviation between the actual air amount passing through the throttle valve and the calculated air amount corresponding to the opening instruction value of the throttle valve is calculated. . Then, by correcting the throttle valve opening instruction value based on the difference between the deviation amounts, the difference between the mechanical opening of the throttle valve and the opening instruction value due to the temperature characteristics of the throttle sensor is corrected. Eliminates and prevents deterioration of controllability.
[0010]
At that time, it is desirable that the opening correction value is gradually increased or decreased so that the difference between the deviation amounts is within the set range, as in the second aspect of the invention.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 relate to an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of an electronically controlled throttle system, FIG. 2 is a flowchart of an ISC learning routine, FIG. 3 is a flowchart of a throttle opening control routine, and FIG. Is a time chart showing the correction of the throttle opening.
[0012]
In FIG. 1, reference numeral 1 denotes an engine, and an injector 3 is interposed in an intake port of the engine 1, and a throttle body 4 that forms an intake passage 2 communicating with the intake port is disposed upstream of the intake port. Has been. The throttle body 4 is provided with a throttle valve 5, and the throttle valve 5 is driven and controlled by an electronic control unit (ECU) 100 through a motor 7 (DC motor in this embodiment) 6 via a gear 7. Are connected. An intake air amount sensor 8 is interposed on the upstream side of the throttle body 4.
[0013]
The throttle valve 5 is urged by a return spring 10a so as to come into contact with the opener stopper 9 when the motor 6 is not energized, and can be retracted when the throttle opening at the opener stopper 9 is in an emergency. Give limp home opening. Further, the fully closed position when the throttle valve 5 is controlled to close by the motor 6 against the biasing force of the opener spring 10 b is regulated by the fully closed stopper 11. In the figure, the position of the throttle valve 5 is schematically shown by a vertical movement.
[0014]
The ECU 100 includes two main and sub microcomputers 101 and 102 (hereinafter referred to as a main microcomputer 101 and a sub microcomputer 102). The main microcomputer 101 and the sub-microcomputer 102 can communicate with each other via a mutual communication interface. The main microcomputer 101 mainly shares engine control such as fuel injection control and ignition timing control. The drive control (throttle control) is shared.
[0015]
Therefore, the main microcomputer 101 receives signals from two systems of accelerator sensors 13 and 13 that detect the amount of depression of the accelerator pedal 12 and two systems of throttle sensors 14 and 14 that detect the opening of the throttle valve 5. At the same time, signals from the intake air amount sensor 8, the crank angle sensor 15, the coolant temperature sensor 16, and other sensors (not shown) for detecting the engine operating state are input, and the fuel injection amount and ignition from the injector 3 are input. The engine control amount such as time is calculated.
[0016]
On the other hand, the sub-microcomputer 102 receives signals from the two accelerator sensors 13 and 13 and the two throttle sensors 14 and 14 as well as data from the main microcomputer 101 to obtain the target throttle opening and Based on the deviation from the actual throttle opening, the motor drive circuit 103 calculates a duty ratio for PWM control of the motor 6.
[0017]
As for the signals from the two accelerator sensors 13, 13 and the two throttle sensors 14, 14, one system is used for normal control, and the other system is used for self-diagnosis. That is, the amount of depression of the accelerator pedal 12 is detected by the double accelerator sensors 13 and 13 and read into the ECU 100 and processed in a double system by the main microcomputer 101 and the sub microcomputer 102 inside the ECU 100, and then the motor 6 Is controlled to an optimum throttle opening, and the movement of the throttle valve 5 is detected by the double throttle sensors 14 and 14 and read into the ECU 100 to monitor whether it is operating normally.
[0018]
A duplex output from the main microcomputer 101 and the sub-microcomputer 102 in the ECU 100 is output to the motor relay 105 via the matching circuit 104. During normal operation, the motor relay 105 is driven by the output of the coincidence circuit 104, and power is supplied from the battery 106 to the motor 6 from the motor relay 105 via the motor drive circuit 103.
[0019]
Here, in the throttle control in the present embodiment, the required torque of the engine is calculated by referring to a map or the like from the accelerator opening based on the signal from the accelerator sensor 13 and the engine speed based on the signal from the crank angle sensor 15, and this required torque. Is corrected in accordance with a request from a traction control unit (not shown) and the upper limit is regulated, and then a target throttle opening for generating the required torque is calculated from the required torque and the engine speed by referring to a map or the like.
[0020]
Further, the amount of air (ISC flow rate) required for idle operation is calculated from the engine speed, cooling water temperature, etc., and this ISC flow rate is converted into a throttle opening (ISC opening) by referring to a map or the like. As is well known, the ISC flow rate compensates for the basic ISC flow rate based on the cooling water temperature, the feedback correction value based on the deviation between the target idle speed and the actual engine speed, and the load and electrical load of auxiliary equipment such as an air conditioner. It is calculated by correcting with a load correction value, a learning value, etc.
[0021]
Then, the final target throttle opening is obtained by adding the ISC opening to the target throttle opening based on the accelerator opening, and the deviation between the target throttle opening and the actual throttle opening based on the signal from the throttle sensor 14 Based on the above, the duty ratio in the PWM control of the motor drive circuit 103 is calculated, and the motor 6 is driven to perform feedback control of the throttle opening.
[0022]
In such throttle control, the ECU 100 eliminates the discrepancy between the actual mechanical opening of the throttle valve 5 and the opening instruction value of the throttle valve 5 output from the ECU 100 due to the temperature characteristics of the throttle sensor 14. During the ISC learning, the intake air amount of the engine measured by the intake air amount sensor 8, that is, the actual air amount passing through the throttle valve 5, and the ISC air amount calculated from the engine operating state, that is, the opening instruction of the throttle valve 5 Learn the amount of deviation from the air amount that gives the value. Then, using the learned value of the deviation amount, the air amount becomes excessive by keeping the correlation between the opening instruction value and the intake air amount of the engine when the operating condition changes and the temperature condition changes. Thus, it is possible to prevent the convergence to the target rotational speed from deteriorating, or conversely, the air amount is insufficient and the target rotational speed is not reached, causing a drop in rotation and unstable engine rotation.
[0023]
Hereinafter, processing related to throttle control in the ECU 100 will be described with reference to the flowcharts of FIGS. 2 and 3.
[0024]
FIG. 2 shows an ISC learning routine executed every predetermined time. First, in steps S101 and S102, it is determined whether or not a learning condition during idling is satisfied. That is, in step S101, it is checked whether or not the coolant temperature TW based on the signal from the coolant temperature sensor 16 is equal to or higher than the set water temperature TWSET, and in step S102, the actual engine speed NE based on the signal from the crank angle sensor 15 is determined. The success or failure of the learning condition is determined by checking whether or not the absolute value NE−NSET of the deviation from the target idle speed NSET is equal to or less than the set value ΔNSET. For example, the set water temperature TWSET is a cooling water temperature value indicating the engine fully warmed-up state, and the set value ΔNSET is a value that defines a convergence control range to the target idle speed NSET.
[0025]
If TW <TWSET in step S101 and the engine temperature has not reached the set temperature, or NE-NSET> ΔNSET in step S102, the engine speed converges within the control range to the target idle speed. If not, it is determined that the learning condition is not satisfied, and the routine is exited. On the other hand, if TW ≧ TWSET in step S101 and | NE−NSET ≦ ΔNSET in step S102, it is determined that the learning condition is satisfied, and the process proceeds to step S103.
[0026]
In step S103, it is checked whether or not the ISC feedback correction value IFB based on the deviation between the target idle speed and the actual engine speed exceeds a first determination value ISET1 that defines an upper limit within the control target range. If IFB> ISET1, the process proceeds from step S103 to step S104, and the set value ΔI is added to the previous ISC learning value ILRNn−1 to be updated to the current learning value ILRNn (ILRNn ← ILRNn−1 + ΔI). The process proceeds to step S107.
[0027]
On the other hand, if IFB ≦ ISET1 in step S103, the process proceeds from step S103 to step S105, and it is checked whether or not the ISC feedback correction value IFB is smaller than a second determination value ISET2 that defines a lower limit within the control stable range. If IFB ≧ ISET2 and the ISC feedback correction value IFB has converged within the control target range, the current learning value is held and the process jumps to Step 107. If IFB <ISET2, the process proceeds to Step S106. Then, the set value ΔI is subtracted from the previous ISC learning value ILRNn−1 to be updated to the current learning value ILRn (ILRNn ← ILRNn−1−ΔI), and the process proceeds to step S107.
[0028]
In step S107, the ISC flow rate obtained by correcting the basic ISC flow rate based on the cooling water temperature with various correction terms from the intake air amount GA of the engine measured by the intake air amount sensor 8 (actual air amount passing through the throttle valve 5). ISCGA is subtracted, the difference is stored in the memory as an air amount deviation amount learning value DGA, and the routine is exited. The air amount deviation learning value DGA is a learning value for keeping the relationship between the actual mechanical opening of the throttle valve and the opening degree command value for control constant with respect to the temperature change. Referenced in the control routine.
[0029]
The air amount deviation amount learning value DGA calculated by the above processing is referred to in the throttle control routine of FIG. 3, and the mechanical opening degree and the opening degree instruction value of the throttle valve 5 caused by the temperature characteristics of the throttle sensor 14. An opening correction value QADJ for correcting the deviation between the two is obtained. Next, the throttle control routine will be described.
[0030]
In this throttle control routine, first, in step S201, the target throttle opening is calculated based on the accelerator opening and the engine speed, and in step S202, the basic ISC flow based on the cooling water temperature is corrected with various correction terms. An ISC flow rate ISCGA is obtained and converted into a throttle opening (ISC opening). Next, the process proceeds to step S203, and the difference between the actual intake air amount GA during idle operation measured by the intake air amount sensor 8 and the ISC flow rate ISCGA is calculated as an air amount deviation amount DGA2 (DGA2 ← GA-ISCGA).
[0031]
Next, in steps S204 and S205, whether or not the flow rate difference (DGA-DGA2) between the air amount deviation learned value DGA learned earlier and the current air amount deviation amount DGA2 is within the set range as the control target. Check out. That is, in step S204, it is checked whether or not the flow rate difference (DGA−DGA2) is greater than a first determination value QH that defines the upper limit of the setting range. If DGA−DGA2 ≦ QH, then in step S205, It is checked whether (DGA-DGA2) is smaller than a second determination value QL that defines the lower limit of the setting range.
[0032]
If DGA-DGA2> QH, the process proceeds from step S204 to step S206 to gradually correct the throttle opening instruction value in the opening direction, and the opening correction value QADJ is set to the previous value QADJn-1. The set value ΔQ is added to be updated to the current value QADJn (QADJn ← QADJn−1 + ΔQ), and when DGA−DGA2 <QL, the throttle opening instruction value is gradually corrected in the closing direction. Proceeding to S207, the set value ΔQ is subtracted from the previous value QADJn−1 of the opening correction value QADJ and updated to the current value QADJn (QADJn ← QADJn−1−ΔQ). If DGA−DGA2 ≧ QL in step S205 (that is, if QL ≦ DGA−DGA2 ≦ QH), the previous value QADJn−1 of the opening correction value ADJ is set as the current value QADJn in step S208. Hold (QADJn ← QADJn-1).
[0033]
Then, after updating / holding the opening correction value QADJ in each of the above steps, the process proceeds to step S209, and the final target throttle opening is obtained by adding the ISC opening and the opening correction value QADJ to the target throttle opening. And exit the routine. That is, as shown in FIG. 4, the difference ΔGA between the intake air amount GA of the engine and the ISC air amount ISCGA learned in advance in a stable state where the ISC learning condition is satisfied is used. Then, correction is performed so that the difference between the intake air amount GA of the engine and the ISC air amount ISCGA when the operating state changes matches the learning value DGA within the set range.
[0034]
Thereby, the deviation between the mechanical opening of the throttle valve 5 and the opening instruction value due to the temperature characteristics of the throttle sensor 14 is eliminated, and even when the temperature condition changes, the same opening instruction value is obtained. On the other hand, the same amount of air can be obtained, the convergence to the target rotational speed can be improved, and the rotational stability can be ensured.
[0035]
【The invention's effect】
As described above, according to the present invention, the deviation between the mechanical opening of the throttle valve and the opening instruction value caused by the temperature characteristic of the throttle sensor is eliminated, and deterioration of controllability is prevented. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an electronically controlled throttle system. FIG. 2 is a flowchart of an ISC learning routine. FIG. 3 is a flowchart of a throttle opening control routine. Explanatory drawing showing the deviation of the opening caused by the temperature characteristics of the sensor 【Explanation of symbols】
1 Engine 5 Throttle valve 6 Motor (actuator)
14 Throttle sensor 100 Electronic control unit DGA Air amount deviation learning value DGA2 Air amount deviation GA Intake air amount ISCGA ISC air amount QADJ Opening correction value

Claims (2)

Control of an electronically controlled throttle engine that controls the opening and closing of the throttle valve via an actuator based on a signal from a throttle sensor that detects the opening of the throttle valve so that the opening of the throttle valve coincides with the opening instruction value A device,
Means for learning a deviation amount between an actual air amount passing through the throttle valve and a calculated air amount corresponding to an opening instruction value of the throttle valve in an idle operation state when a learning condition is established ;
Means for calculating a deviation amount between an actual air amount passing through the throttle valve and a calculated air amount corresponding to the opening instruction value of the throttle valve in an idle operation state other than the idle operation state when the learning condition is satisfied When,
A control device for an electronically controlled throttle engine, comprising means for calculating an opening correction value for correcting the opening instruction value of the throttle valve based on the difference between the deviation amounts . 2. The control device for an electronically controlled throttle engine according to claim 1, wherein the opening correction value is gradually increased or decreased so that the difference between the deviation amounts falls within a set range.

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